2021 IWC Preliminary Technical Program
– (all times local and subject to change)
Talking Stick Resort, Scottsdale, AZ, USA
Monday, 11/8/2021; 8:00 AM
M1-Business of Water
IWC Rep: Scott Quinlan P.E., GAI Consultants, Inc., Cranberry Township, PA
Session Chair: John Yen, Graver Water Systems, Warren, NJ
Discussion Leader: Juvencio Casanova, Evoqua,
At the heart of every decision is the business case to justify a purchase or rental of a water treatment system combined with construction, engineering and installation. Ultimately all of these factors are linked to the impact on capital and operating expenses combined with socio-economic and regulatory drivers. This session explores several business cases and lessons learned in the microelectronics, po-table water and wastewater markets.
8:10am IWC 21-01: Stakeholder Engagement during Impaired Water Treatment Construction Projects
Brian Petty, P.E., and Hamid Amini, Ph.D., Geosyntec Consultants, Huntington Beach, CA
Water source vulnerability assessments, environmental justice, climate change, and public scrutiny are driving significant demand for delivery of sustainable water projects. At the same time, funding for these projects may be difficult to secure and traditional technologies and project delivery methods are often not well-suited for implementing them rapidly and at large scale. Consequently, there has been an evolution in the depth and breadth of projects being delivered under public-private partnership (P3), design-build (DB), construction management at risk (CMAR), and by creating linkages between public and private owners, communities, and regulatory agencies.
This paper focuses on important observations and lessons learned by describing case studies that include:
- Large-scale green infrastructure implemented under a P3 framework to benefit disadvantaged communities and improve water quality and reliability.
- Accelerated construction of wastewater treatment infrastructure after flooding and landslides, even under pandemic restrictions and supply chain interruptions.
- Designer-led CMAR projects that facilitate construction of innovative and novel technologies requiring close contractor, designer, and owner coordination to realize the full potential of custom approaches to challenging environmental issues.
- Supplemental environmental projects (SEPs) that link together private parties and utilities to share resources and risk for new multi-benefit water supply elements.
Allocating risk and responsibility among team members was a key consideration for each of these projects, as was proactive stakeholder engagement to identify and address concerns cost-effectively and without schedule delays. Detailed review and allocation of risk was especially important for the novel projects because of the one-of-a-kind nature of the technologies or the project settings. These elements will be described, and results will be provided to demonstrate how water quality was improved and water reliability issues were addressed.
9:00am IWC 21-02: Improving Disinfection Performance in an Urban Drinking Water System
Darrin Lowe and Michael Soller, P.E., CPC, DBIA, Bowen Engineering Corporation, Indianapolis, IN; Grady Stout, Tennessee American Water, Chattanooga, TN
Water treatment systems serve populations which are remote and urban alike and assuring a disinfection residual in the distribution system is critical to public health. Using Flocculation and Sedimentation has been time tested to assure treatment and decrease turbidity prior to filtration. The use of lamella clarifiers or inclined plate settlers has shown to increase plant capacity in the same footprint as traditional sedimentation basins. This change causes plants to implement new waste and control systems.
In addition, owners want definitive project delivery solutions to meet their spending limits and regulatory completion timeframes. Because their internal engineering staffs are shrinking, some owners are using alternative project delivery methods to quickly collaborate on the best technical solution while simultaneously agreeing on the implementation plan thereby reducing capital and life cycle costs.
This case study paper describes the design development and lessons learned from a collaborative project that involved replacement of a flocculation and sedimentation basin for a 65 MGD drinking water plant while the plant remained in operation. Further complicating the project was another existing basin adjacent to the proposed new basin. The case study describes the recommended changes which were implemented prior and during construction. The case study describes the business case for the process change and the construction challenges with implementing the project on a 10 month construction schedule after the design was revised.
The paper also describes the lean construction control processes used to assure field production, quality and safety despite an accelerated schedule. This case study paper concludes with lessons learned for implementing treatment solutions, assure a definitive schedule outcome, while decommissioning and building in a limited access area.
10:10am IWC 21-03: First Stage Design & Start-up of a Zero-Liquid Discharge (ZLD) Facility to Produce
Ryan Sullivan, Americus Mitchell, and Sahil Azeez, Sundt Construction, Tempe, AZ
Access to water is a critical factor in the production of microelectronics, with manufacturing often located in stable climates to take advantage of consistent weather and atmospheric conditions. However, these locations can be arid and water scarce, making clean water relatively expensive and often requiring users to consider options for recycle and reuse. This paper highlights the design and startup of the first portion of a facility’s efforts to renew their used plant wastewater back to an advanced water quality utilizing a zero-liquid discharge (ZLD) design. The plant will have a capacity of 13 MGD, with 95% recovery and a salt discharge largely made up of sodium sulfates.
The first stage of the design is focused on the removal of total suspended solids (TSS), COD/BOD, ammonia, nitrogen, peroxide and tetra-methyl ammonium hydroxide (TMAH), a common chemical in microelectronics. The process begins with the introduction of a catalase to reduce peroxide to oxygen and water. This is followed by an anoxic zone, an aerobic zone and a final anoxic zone. Suspended solids separation is achieved through hollow fiber membranes with pore sizes of up to 0.1 microns operated under vacuum. The overall design and expected reactions are further detailed in this paper.
There were numerous process hurdles not uncommon to the start-up and operations of this sort of plant, but this paper will cover some of the more unique items relating to flow demand, biology and optimization of the plant’s start-up. This includes operation of the plant in a continuous low flow state, operating the membrane bioreactors with compromised fibers, issues resulting in unwanted hydrogen sulfide gas formation and the impacts of controlling outfall total nitrogen while optimizing the total dissolved solids (TDS) treatment systems.
Monday, 11/8/2021; 8:00
M2-Removal of Trace Contaminant – Potable / Ground Water
IWC Rep: Patricia Scroggin-Wicker, P.E., Burns & McDonnell, Kansas City, MO
Session Chair: Ajit Dighe, Thermax, Houston, TX
Discussion Leader: Sam Fackrell, Bowen Engineering Corp., Glen Burnie, MD
The regulated contaminants such as Radium, Barium, Arsenic, Manganese & Oxidation, is driving research and product development for ways to remove trace contaminants to ever lower limits. This session features paper explores research on using Ion Exchange resin & Oxidation process cases studies for removal of various trace contaminants from potable / ground water.
8:10am IWC 21-04: Radium Removal from otherwise Potable Water. Lessons learned with a Radium Selective Hybrid Ion Exchanger
Peter Meyers and Kaitlyn Clark, ResinTech Inc, Camden, NJ
The radium selective hybrid ion exchanger has been around for quite a while now, the original patents were issued to Dow back in the middle 1980’s. This hybrid is a strong acid cation exchange resin with barium sulfate deliberately precipitated inside the polymer, adjacent to the ion exchange sites. In use, radium first exchanges into the cation resin, according to the laws of ion exchange selectivity, then replaces barium in the barium sulfate precipitant (principal of least soluble compound).
Removal of radium is virtually complete, at least in waters with TDS in the potable water range. Because the daughter products of radium decay are significantly more radioactive than radium itself, radium can in some cases collect on the hybrid at a high enough concentration to make disposal of the spent media problematic. One of these daughter products is radon, which can significantly increase in the effluent. Adoption of this technology has been slow. Aside from issues about spent media disposal, use of the radium selective hybrid has been hindered by the media’s disturbing tendency to sometimes leach barium well above the federal MCL of 2 mg/L.
Although Dow recommended adding supplemental sulfate to the feedwater as a way to mitigate barium leaching, feeding supplemental sulfate was not always successful. Although Dupont no longer makes this product, ResinTech makes a similar hybrid and has experienced similar problems with barium leaching. In this paper we take up the question of why barium leaches from the hybrid, at what concentrations, and how the various bulk ions in the feedwater affect this leaching. Data from several commercial installations is presented as well as the results of ResinTech’s research.
9:00am IWC 21-05: Trace Arsenic and Manganese Removal from Complex Influent Groundwater
Shira Colsky, James Deitsch, and Hariprasad Parthasarathy, Geosyntec Consultants, Kennesaw, GA; Balaji Seshasayee, Geosyntec Consultants, Chicago, IL
At a large industrial site in the Mid-Atlantic US, groundwater containing over forty different contaminants of concern is extracted and conveyed to a treatment system and discharged into a municipal storm drain. The 100 gpm-capacity treatment system is designed to treat metals, pesticides, and chlorinated compounds to meet exceptionally low effluent water quality criteria. The extremely low arsenic discharge limit is 25 times below the drinking water maximum contaminant level (MCL), while the manganese discharge limit is roughly a factor of five lower than the most stringent criterion applied at the 23 sites regulated in the vicinity of the site. These ultra-low limits are the driving forces in the treatment system design and, although rare at present, are likely to become more widespread in industrial water treatment due to regulatory changes and increased public awareness of water quality. Therefore, the design approaches used for this project are anticipated to be increasingly important for the regulated community.
This case study describes the rationale and sizing for each treatment unit. The primary process for removal of trace metals is an aeration/oxidation system to oxidize trace metals to precipitable solids then solids removal via a downstream crossflow filter. Due to the complexity of the influent water quality and the stringent discharge criteria for both organic and inorganic contaminants, the treatment system also includes media filtration/adsorption for metals polishing, granular activated carbon for trace organics removal, and sludge dewatering to manage residuals. The media filtration vessel contains either adsorptive or catalytic media, the selection of which is based on the governing trace metal discharge limit (i.e., manganese or arsenic). The catalytic media will be the appropriate technology if the manganese discharge limits are governing, while adsorptive media will be the appropriate technology if arsenic discharge limits are governing. This presentation will discuss regulatory drivers and resulting design components and modifications.
10:10am IWC 21-06: Ultraviolet Advanced Oxidation Processes and Onsite Chemical Generation
Ben Satterfield, Simon Dukes, and Josh Griffis, Evoqua Water Technologies, Lowell, MA
UV mediated Advanced Oxidation Processes (AOPs) use hydrogen peroxide, persulfate and, more recently, the hypochlorite anion to oxidize organic micropollutants in a wide range of water matrices ranging from reuse applications to ultrapure process waters. With stricter environmental regulations for contaminants of emerging concern and vastly improved technology, the use of AOP has grown considerably since first being employed in the 1980s.
Recently, Evoqua has advanced AOP technology by reducing operational cost and reliance on vast chemical storage through an improved process scheme. This breakthrough uses efficient onsite generation of multiple oxidants to result in a scalable, cost-effective, and potentially chemical-free method for destroying organic contaminants in a wide range of applications.
In this paper, we will outline the uses for UV activated AOPs, compare oxidants for different applications, review the costs and benefits of onsite chemical generation when compared to bulk chemical, and explore some of the challenges that are experienced when destroying low levels of micropollutants in various feed waters.
Monday, 11/8/2021; 8:00
IWC Rep: Brandon Delis, P.E., Electric Power Research Institute, Charlotte, NC
Session Chair: Joshua Pendergrass, P.E., Stantec, Nashville, TN
Discussion Leader: Rebecca Osteen, Southern Company Services, Birmingham, AL
Poor cooling water quality can result in equipment fouling, reduced heat exchange rates, and damage to critical process equipment that can lead to unplanned downtime. This session will explore several operational and process control approaches to prevent cooling water degradation and treat systems effected by fouling
8:10am IWC 21-07: The Art and Science of Treating Once-Through Cooling Water
Jasbir Gill, Ph.D., Water Energy Solutions Inc., Naperville, IL
Once-through cooling requires a large quantity of the water, however, the consumption is very low as only a very limited amount of water is lost either to evaporation or seeping through ground. Most of the once-through cooling is used in the power generation where either rivers or impounded lakes are the source of water. An impaired water, produced water or sea water can also be used without pre or post treatment. Optimization of chemical treatment is very important because of the large quantity of the water and also to prevent overfeeding, which may take away the lake’s ability to self-soften.The paper discusses various technologies and models for inhibitor optimization, such as taking advantage of self-softening of lakes, treating the water only for the duration in the heat exchanger, automation and control, and predicting the on-set of precipitation event for better management. The on-set of precipitation deploys simple on-site laboratory test “Cooling Lake Inhibitor Optimization” (CLIO) to determinate real time potential for precipitation of the supersaturated mineral. This test is also helpful to tae advantage of any natural inhibitor or residual treatment inhibitor present in the lake.
9:00am IWC 21-08: Non-Phosphorous Passivating Chemistries for Heat Exchangers
Mary Jane Felipe, William Watson, and Swamy Margan, Baker Hughes, Sugar Land, TX
The maintenance of the reliability and heat transfer efficiency of heat exchangers are key factors in optimizing refinery operations. To maximize the service life of the heat exchange equipment, pretreatment is typically done. During turnarounds, operators clean heat exchangers by removing the accumulated scale and thick metal oxide layer. After the cleaning, these heat exchangers are passivated by introducing a prefilmer that forms a protective film rapidly on the heat exchanger surface. Passivation of cooling water systems after a turnaround is a recognized best practice that extends the life and performance of mild steel heat exchangers. Without proper passivation, corrosion products quickly develop on mild steel tube surface creating deposits and increasing the potential for under deposit corrosion.
A common prefilming or passivating agent for mild steel heat exchanger metallurgies during turnaround is phosphate-based chemistries. To achieve rapid film formation, the phosphate chemistries are dosed in very high level. After the passivation procedure, it is often required that the phosphate passivating solutions be blown down before heat load is applied to the tower. This is to minimize the chance of phosphate fouling. In addition to possible phosphate fouling when using phosphate-based chemistries, releasing the phosphate on discharge streams is also a concern.
This paper presents an effective and reliable non-phosphorous passivation chemistry for heat exchangers. Field data shows very low corrosion rate was achieved during passivation and no further corrosion nor fouling was observed during heat load. Formation of the non-phosphorous containing film on the mild steel metallurgies was confirmed using X-ray photoelectron microscopy and electrochemical studies.
10:10am IWC 21-09: Wrong Selection of Antiscalant and Consequences at Sulfate Removal Facility
Hussain Alramadhan, Saudi Aramco, Al-Andalus, Al-Hassa Saudi Arabia
This paper shares the experienced encountered during the initial start-up of a Sulfate Removal Faciltiy. This facility is design to reduce the sulfate contact in sea water from 4,400 ppm to less than 200 ppm. As a result, the reject water is highly concentrated with Sulfate (more than 17,000 ppm), so, proper selection of antiscalant is required. However, the antiscalant selection was not correct causing the plant to trip due to heavy scaling buildup on the NF Membrane and all downstream piping and valves which required massive cleanup efforts to bring the facility back to service.
The paper will also discuss the engineering and experiments effort to troubleshoot this sudden plant trip and the raise in differential pressure across the NF Membrane as it was not clear at first what cause these issues. This effort required the involvement from multiple engineering parties from within the company, NF package supplier, NF Membrane manufacturer and Antiscalant vendor.
Monday, 11/8/2021; 8:00
M4-Process: Innovations and Optimizations in Water Use and Recovery
IWC Rep: Jim Summerfield, Dupont Water Solutions, Saginaw, MI
Session Chair: Donna Murphy, Dupont Water Solutions, Spring House, PA
Discussion Leader: Dan Cicero, Nalco ,
This session’s papers will discuss ways to reduce and or recover water starting with a case study audit on water usage from source through discharge, a paper on optimization of a solids dewatering system and a paper on an innovative low energy thermal evaporations system to recover water from high TDS streams such as MLD/ZLD for reuse.
8:10am IWC 21-10: Case History: Efforts to Minimize Raw Water Usage and Wastewater Discharge at a Large Industrial Facility
Daniel Sampson and Cristina Piekarz, HDR, Walnut Creek, CA; Josh Prusakiewicz, HDR, Ann Arbor, MI; Ben Stanley and Dave Engelman, DGC Operations, LLC, Middletown, NY
CPV Valley Energy Center is a 2×1 combined-cycle electrical generating facility with an Air-Cooled Condenser (ACC). While the ACC contributes to a significant reduction in overall water use at a combined cycle facility, Valley was struggling with high usage and discharge rates. Critical water management issues included higher greywater intake and discharge costs, higher chemical usage, heat losses in the HRSG’s (which led to lower thermal efficiency) and higher operator demand to maintain plant chemistry and tank levels.
The O&M team collaborated to develop the following key action items:
- Perform a comprehensive review of chemistry logs with the plant’s water systems consultants.
- Modify and optimize the plant’s cycle chemistry control strategy (intermittent and continuous blowdown rates) to maintain chemistry within acceptable limits while dramatically reducing blowdown and quench water rates.
- Meet monthly with the O&M team and the plant’s chemistry consultants to address water issues and concerns.
- Perform a detailed survey to find leaking drain valves in the system.
- Replace or rework leaking valves in the steam cycle to minimize water loss.
- Review and optimize water treatment system self-cleaning and backwash rates to reduce waste further.
- Update operator process screens to show daily costs of intake and discharge rates to raise awareness of the impacts to budget.
- Create a conceptual design and test a low-TDS wastewater reclamation system.
This paper will describe the plant’s actions and results, what did and did not work well. The net impact of this work included:
- Significant reduction in monthly water use, discharge rates and chemical use and costs over previous months.
- Overall net plant efficiency (heat rate) improvement.
- Reduced wear and tear on water treatment system components (less operation, cleanings, and filter replacements).
The plant’s experience clearly shows that little things matter and that good ideas may carry unintended consequences. The O&M team addressed issues undoubtedly experienced by many, if not most, industrial facilities endeavoring to reduce their water footprint. Valley’s experience will benefit other facilities with similar goals.
9:00am IWC 21-11: Beyond the Filter Press Leachate Dewatering Design Alternatives
Ron Ruocco, Stantec, Charlotte, NC; Philip Pedros, Stantec, Burlington, MA; Peter Daniels, Stantec, Golden Valley, MN; Mayra Giraldo, Stantec, Atlanta, GA
Typically physical/chemical treatment system utilizing flocculation/clarification and thickeners and filter presses for dewatering. The physical/chemical treatment is typically designed to co-precipitate heavy metals such as zinc to prevent inhibition of subsequent activated sludge biological process. The solids loading based on the original treatability tests was anticipated to be in the 3,000 mg/L TSS range.
Upon further investigation the calcium content exceeded that of the original treatability tests so the design incorporated soda ash to precipitate the excessive calcium as calcium carbonate. The calcium content and the precipitation of calcium carbonate in the influent solids loading after primary physical/chemical treatment suggested TSS as high as 14,500 mg/L was possible.
A Mode 1 operation that uses a rotary drum thickener as the primary solids separation device was incorporated. The rotary drum thickener is designed to receive between 1% and 2% influent suspended solids. A Mode 2 operation can also be used during periods of low influent solids with the flocculation/clarification used as the primary separation device rather than the rotary drum.
The two modes are advantageous due to the potential of fluctuations in flow and concentration over and above the sampling and evaluation period used to size the equipment. Basically Mode 2 uses the “Flocculation/Clarification” step as the primary separator device where as Mode 1 uses the “Rotary Thickener(s)” step as the primary separator device.
Optimization as usual proves to be the key to sustainable operation and requires periodic lab treatability testing to confirm polymer and coagulant doses.
This paper presents the design and operational details intricate to this design and contrasts other dewatering equipment alternatives such as centrifuges, belt presses and rotating screens that are all operator friendly, but water use intensive to one degree or another. Filter Presses can be operator intensive unless fully automated.
10:10am IWC 21-12: Low Energy Ejector Desalination System (LEEDS)
Jorge Aguinaldo and Joseph Kanzleiter, Bechtel Oil, Gas & Chemical, Inc., Houston, TX
LEEDS is a newly developed innovative thermal desalination process that uses water driven highly efficient multi-phase ejector (MPE) instead of mechanical vapor compressor or blower in a mechanical vapor compression evaporator system to recover water or distillate high saline water. The advantages of LEEDS is its lower energy consumption compared to conventional mechanical vapor compression (MVC) evaporators and other thermal desalination processes. Like the mechanical vapor compressor the multi-phase ejector (MPE) compresses the steam and resulting heat is used to heat the high salinity stream. The advantage of the LEEDS is lower CAPEX and OPEX. The use of MPE ejectors and off-the-shelf motive pumps significantly reduces the CAPEX and reduces delivery period. Applications of LEEDS are Minimal Liquid Discharge (MLD), Zero Liquid Discharge (ZLD) facilities, power plants, chemical process industries and manufacturing plants where MVCs are currently used. This presentation describes the pilot test results when treating actual produced water from Permian Basin.
IWC 21-M4R: Removal of Microplastics from Water with a Magnetic Ferrofluid
Ahmad Pourmovahed, Zachary McKay, Alexander Speer, and Kyle Alburtus, Kettering University, Flint, MI
From large fishing nets to microscopic pieces originating from synthetic clothing fibers, plastics have been polluting the environment and our drinking water for decades. This article serves to provide further awareness of the dangers of plastic pollution and presents the results of a student design project which investigated and replicated an experimental method for removing microplastics from water by using an energy efficient apparatus. Once scaled, this design may serve as an addition to water treatment plants and remove microplastics from drinking water. The method, previously documented by a young inventor, mixes water containing microplastics, oil, and a ferrofluid invented by NASA. Since plastics and oil are non-polar, they are attracted to each other and coagulate with the ferrofluid after which a strong magnet is used to extract the coagulated mixture, leaving behind purified water. The designed system has three stages and depends on gravity for water flow until the process is complete. A small DC motor powers a mixing device inside the top section mixing prescribed amounts of water, microplastics, olive oil, and ferrofluid during which the coagulant forms, trapping the microplastics. The coagulant and impurities will then settle to the bottom of the top container where they will rest until a valve is opened to release the fluid into the second stage. Stage two includes a 3-D-printed magnetic filter. The magnetic filter housing is made up of an outer housing and a magnetic roller driven by another motor. The outer housing acts as a funnel for the fluid flowing from the top container. The fluid is directed towards the middle of the housing where a spinning magnetic roller uses magnetic attraction to collect the coagulant. The remaining fluid runs over the roller and out of the bottom of the magnetic filter into the middle container. A hole in the bottom of the middle container allows the purified water to flow into the final stage. The purified water is then tested using a spectrometer for light absorbance rates. The light absorbance recorded from water samples is compared to the known concentrations also tested to establish a baseline. The results are used to determine the exact amount of microplastics that remained in the water after flowing through the system. The design is efficient and environmentally friendly as no pumps are used. This system can remove around 65% of the microplastics at an estimated cost of 25 US₵/L of water.
Monday, 11/8/2021; 1:15 PM
M5-Full Spectrum Mine Wastewater
IWC Rep: Paul Pigeon, Golder Associates Inc., Lakewood, CO
Session Chair: Evan Claytor, SUEZ Water Technologies & Solutions, Richmond, VA
Discussion Leader: Don Downey, Purolite Corporation, Paris, ON, Canada
Process water plays a critical role in mining operations, but it can also lead to costly waste treatment solutions for owners. The mining industry faces many challenges from the rising and falling of commodity prices, to environmental regulations and even governmental policies. The four papers presented in this session look to not only solve environmental issues but also demonstrate that water companies can bring solutions which help stabilize operations and increase profitability.
1:25pm IWC 21-13: Pilot Study of HDS Process treating concentrated mine water
John Schubert, HDR, Sarasota, FL; Sriram Ananthanarayan, BHP; Mark Owens, HDR
The closure of inactive mine sites requires the disposition of water that has over time accumulated onsite. This involves the treatment of a potentially large volume of water to meet discharge criteria. In one specific case, a large volume of water had accumulated from mining operations. The water is characterized as being highly acidic, with a high sulfate and TDS concentration, and large concentrations of a variety of metals and metalloids. It is expected that treatment of the accumulated water and groundwater flowing into the pit will continue long term. Several processes are currently under consideration for removal of the bulk of the major wastewater constituents, including sulfate, fluoride, aluminum, copper, iron and host of metals and metalloids at lower concentrations including arsenic, selenium and molybdenum. As an initial evaluation, the High Density Sludge (HDS) process was selected for lab scale pilot study. The study was conducted in HDR’s process research lab in February and March, 2021. The pilot system operated at a flowrate of nominally 100 ml/min, under a variety of operating conditions. A critical concern was the high strength of the wastewater and the resulting high solids formed in neutralization. This paper will describe the wastewater characteristics, pilot system configuration, effluent concentrations of critical parameters, and the general interpretation of results.
2:15pm IWC 21-14: Arsenic Removal Pilot for Waste Liquor from Metal Refining Roaster
John Van Gehuchten and Katherine Van Sice, McKim & Creed Inc., Sewickley, PA
A metal refining roaster in Pennsylvania generates a weak acid waste stream from the system’s scrubbing system. This low-pH waste liquor also contains trace metals that must be removed before the water can be discharged from a permitted outfall.
A pilot was conducted to evaluate the optimum conditions for removing the arsenic concentration from just approximately 500 parts per billion to less than 100 parts per billion. However, this process was not straight forward due to the complex nature of the wastewater and the associated matrix effects that impacted sampling. The number of other trace materials in the water also influenced the ability to co-precipitate arsenic.
This pilot, which took place over a 30-day period, evaluated the combination of optimum pH and iron dose to remove arsenic to the required level. This pilot had to overcome variable influent flow quality, existing process control variability, a constrained operating environment, equipment complications, and other obstacles. This paper will present data with respect to the water quality trends, treatment conditions applied, optimizations made during the process, and other relevant field obtained data.
3:20pm IWC 21-15: Troubleshooting Hollow Fiber UF System at Operating Acid Mine Drainage Water
Louise Murphy and Victor Wirick, Golder, Lakewood, CO
This paper examines troubleshooting methodology for a hollow fiber ultrafiltration (UF) system used as a polishing step in treating acid mine drainage at an operational water treatment plant. Pretreatment steps include iron co-precipitation and lime low density solids precipitation. The UF was not operating properly, resulting in excessive operator intervention and effort maintaining and troubleshooting the system. The UF was unable to maintain required process flow rates, running at pressure differentials near the system maximum, and could not complete a clean in place (CIP) clean due to precipitate plugging the pre-filters and valve and heater failures. UF membrane replacement was thought to be the best solution by the site, despite the membranes having only operated for three years.
Following a site visit and discussions with the operators, a troubleshooting plan including immediate and long-term fixes was proposed. The vendor was contacted for further understanding of the issues. Two membrane autopsies were performed to provide additional insight into the issues observed with the membranes and further troubleshooting. Based on the information gathered, possible solutions were prioritized based on risk and implementation effort. Solutions provided have allowed the system to run without major issues with the current membranes. Cleans in place are run as a matter of routine when normalized flux reaches an agreed upon value, not as an emergency effort to regain process flow.
Priorities and considerations made when proposing and implementing solutions will be discussed, as well as lessons learned throughout the troubleshooting process.
4:10pm IWC 21-16: Pilot Study of Solvent Extraction/Electrowinning for Copper Recovery
John Schubert, HDR, Sarasota, FL; Sriram Ananthanarayan, BHP; Chloe Grabowski, HDR, Missoula, MT
A mine owner is undertaking closure studies of its inactive mine sites in the southwestern United States. As part of the closure studies, large inventories of pit water at its closed sites will require treatment prior to discharge. The water is characterized as being highly acidic, with significant concentrations of sulfate and Total Dissolved Solids. Several metals including aluminum, copper, iron, manganese and magnesium are present in high concentrations ranging from high hundreds to thousands of mg/L. A variety of other metals and a number of rare earth elements are present at lower concentrations ranging from 5 to 50 mg/L. An initial evaluation, which considered potential economics and process viability, indicated a sufficient concentration of copper is present in the pit water to consider recovery of copper as a byproduct prior to further treatment of the water for discharge. The study further indicated that the highest return on investment is expected to be from the solvent extraction /electrowinning process (SX/EW). A lab scale flow through pilot study was conducted to evaluate the performance of the process. This paper describes the lab study, the results of the study, and conclusions related to the product quality and economic viability of the process.
Monday, 11/8/2021; 1:15 PM
M6-Trace Contaminant Treatment
IWC Rep: Jay Harwood, SUEZ Water Technologies & Solutions, Oakville, ON, Canada
Session Chair: Peter Meyers, Resintech,
Mass limits for wastewater discharges containing contaminants such as selenium and arsenic often result in concentration limits well below the MCL’s established for potable water. These (sometimes seemingly impossible) limits drive research and product development for passive ways to remove these contaminants that don’t require constant vigilance. This session features papers that explore common attributes of trace contaminants as well as recent innovations in passive treatment technologies being used for their removal.
1:25pm IWC 21-17: Fundamentals of Trace Contaminant Removal and Long Life Medias
Kaitlyn Clark, ResinTech Inc., Camden, NJ
The removal of trace contaminants in water depends as much or more on the concentrations of the bulk ions in the water as the concentration of the trace contaminant. Often, trace contaminants are presents at the parts per billion (ppb) or parts per trillion (ppt) level in a see of harmless bulks ions on the order of 100-1000 parts per million (ppm).
Since the trace contaminants are present at such low concentrations, meaningful throughputs may be achieved with ion exchange resin even if the trace contaminant is not a preferred ion. When the trace is preferred, very long throughputs may be achieved. In cases where the resin has a high affinity for a trace contaminant it may be operated on a single use basis with no regeneration.
This paper focuses on the fundamentals of trace contaminant removal. The principle of concentration difference in trace contaminant removal, the importance of the water analysis in designing treatment plans, cases where regenerable or single use are preferred, and common pitfalls of single use systems will be discussed.”
2:15pm IWC 21-18: Biological Removal of Soluble Arsenic
Thomas Higgins, Worley, St Augustine, FL; Michael Finneran, American Electric Power, Columbus, OH; Heyward Suber, Worley, Atlanta, GA
In October 2020, the United States Environmental Protection Agency (EPA) issued final revisions to the final 2015 Steam Electric Power Generating Effluent Guidelines (ELGs), with regulatory changes for flue gas desulfurization (FGD) wastewater with stringent limits for arsenic.
The ELG limit for arsenic is for Total Arsenic. Treatment strategies for removing arsenic from wastewater are typically tailored to remove the predominant form of arsenic in the wastewater. Arsenic in FGD wastewater is primarily present in its particulate forms due to presence of high concentrations of iron solids in FGD wastewater and the acidic operating pH used in scrubbers. The typical physical /chemical wastewater treatment methodology used for FGD wastewater treatment is very effective at removal of particulate arsenic. These treatment systems are focused on settling of suspended particles and often include chemical addition systems to promote the removal of suspended solids.
The ELG limit for arsenic are based on limited data, however, the severity of the limit indicates that simply removing the particulate forms of arsenic present in FGD wastewater may be insufficient to consistently maintain compliance. It will likely be necessary to remove a significant portion of the soluble arsenic present in the FGD wastewater to achieve and maintain compliance with the ELG limit.
Soluble arsenic can be coprecipitated with iron hydroxide or absorption (substitution for hydroxide) on ferric hydroxide particulate media. This removal is optimum at neutral to acidic pH. Removal effectiveness is reduced at alkaline pH. Most physical/chemical treatment systems for FGD wastewater are not equipped to perform this type treatment.
Selenium, like arsenic is not consistently removed using typical FGD wastewater physical/chemical treatment methods. As a result, ELG limits for selenium are based on biological treatment followed by ultrafiltration. Studies have shown that this combination is effective at removal of selenium. There have been no reports on removal of soluble arsenic; however, these methods may also provide the desired level of arsenic treatment to achieve compliance.
In this paper, we will demonstrate that soluble arsenic is not removed using standard physical and chemical treatment systems in place for treating FGD wastewater using data from multiple treatment plants. We will also present data from an active FGD biological treatment system where there is significant removal of soluble arsenic, sufficient to achieve the ELG limit.
3:20pm IWC 21-19: The Long Game – Passive Selenium Removal for Long-term Water Management
Andrew Holmes, Kevin Dufresne, Silvia Mancini, and Janet Goodfellow, Geosyntec Consultants, Guelph, ON, Canada
Regulation of selenium continues to be a primary focus of Canadian and US regulators, imposing stringent water quality guidelines which introduce added challenges for mines, power generating facilities, refineries and other natural resource processing facilities faced with the need to invest in expensive active water treatment plants. These water quality guidelines are especially sensitive for mines nearing closure which are facing costly post-closure treatment obligations. In addition, the power industry continues to face the same selenium regulations which drive treatment planning for selenium management on-site for flue gas desulphurization wastewater and ash pond closure activities. Over the past five years, there has been a significant shift towards the development of passive and semi-passive water treatment options to replace or supplement active water treatment plants in an effort to sustainably manage selenium issues in the long term. Microbially-mediated passive or semi-passive reduction of selenium in impacted water can provide cost-effective water management solutions.
Our presentation will review a number of case studies for a variety of water sources in which passive and semi-passive treatment was successfully applied to reduce effluent selenium concentrations to meet stringent effluent limits (< 5 μg/L). A range of passive and semi-passive treatment configurations have been applied to selenium treatment challenges, including Gravel Bed Reactors (GBRs), and these generally consist of an engineered bed of gravel/media through which impacted water is passed and treated using biological processes. For biological processes, amendments such as electron donors and nutrients are added to the water at the inlet of the treatment system to promote the growth and activity of naturally occurring microbes. These microbes are capable of reducing the inorganics and sequentially immobilizing the metals in the media bed. Denitrification and selenium reduction are microbially mediated mechanisms by which nitrate and selenate in impacted water are reduced to nitrogen gas and elemental selenium.
4:10pm IWC 21-20: Sequester Technology Provides Selenium Removal as a Straightforward Extension of Current FGD Wastewater Treatment
Brad Buecker, ChemTreat, Inc., Lawrence, KS; Vladimir Djukanovic, ChemTreat, Inc., Ashland, VA
In 2015 the US EPA finalized the most recent effluent limitation guidelines (ELG), whose revisions placed significant restrictions on discharge of toxic wastewater pollutants from coal-fired power plants. A primary focus was on metals discharge, but the new guidelines also included some non-metals, notably selenium in wet flue gas desulfurization (WFGD) wastewater streams. At that time, biological methods were considered “best available treatment (BAT)” technology for selenium removal. However, management at City Water Light and Power (CWLP) in Springfield, Illinois concluded that they could not justify the capital, operational, and maintenance costs for a biological treatment system to lower selenium concentrations to the ELG limits.
In the summer of 2020, CWLP personnel conducted a field trial of the physical/chemical selenium treatment technology SeQuesterTM developed by ChemTreat. The trial was performed on a side-stream of the existing FGD wastewater treatment influent, with the slipstream being routed through a series of reaction vessels to remove the selenium oxyanions, selenite and selenate, produced during the WFGD process. The results of the trial proved not only the potential for CWLP to meet and stay below the new proposed selenium discharge limit, but offers the utility a more viable option to biological treatment methods. This paper will provide a discussion of selenium and its speciation in the FGD process; the reasons why CWLP chose to test this technology; and the results of the trial, including data about removal of other impurities besides selenium. It concludes with CWLP’s plans to move forward in meeting the new ELG.
Monday, 11/8/2021; 1:15 PM
M7- MLD, ZLD, and Brine Management
IWC Rep: Lyndsey Wiles, Microdyn-Nadir (on sabbatical), Goleta, CA
Session Chair: Elke Peirtsegaele, Microdyn-Nadir, Goleta, CA
Discussion Leader: Matthew Flannigan, Nalco Water, an Ecolab Company, Naperville, IL
Wastewater treatment using membrane technology is becoming more and more prevalent across the globe as fresh water sources continue to dwindle. In attempt to treat and reuse water and wastewater as a means of protecting fresh water sources, industrial and municipal facilities are requiring creative approaches using membranes for sustainable and cost-effective solutions. In this session, we will examine how innovations in material science have led to a new generation of RO elements that use thin-membrane technology to offer more surface area, realizing lower capital and operating costs. We will also learn how various wastewater treatment systems around the world were updated from conventional treatment schemes to more sustainable treatment solutions, allowing these systems to treat difficult wastewater streams while meeting tightening discharge and reuse limits without the need for excessive chemical use, thermal equipment, or extensive brine management.
1:25pm IWC 21-21: Benefits of Operating the First Membrane Systems Utilizing New Thin-Membrane
Rich Franks, Myles Davis, and Craig Bartles, Hydranautics, Oceanside, CA; Lance Thibodeaux and Sam Pallares, LA Sanitation and Environment, San Pedro, CA
In the past year, several membrane systems were started using new, Thin-Membrane Technology which allows the highest active membrane area to be manufactured into the standard spiral wound element. These new membrane systems, which include RO for municipal wastewater reclamation and NF operating on offshore oil platforms, are the first of their kind in utilizing the new technology and demonstrate how wide range of applications can benefit from this innovation.
The spiral wound element was developed in the 1970s to package RO and NF membrane material into a compact, efficient and usable unit. Since that time, incremental improvements in element design and materials of construction have led to enhanced efficiencies and productivity. However, the overall element design has remained largely unchanged. Most notably, in recent years, efforts to fit more material into the present spiral element configuration reached an optimal plateau. Advances in automated manufacturing resulted in either increasing element surface area or increasing thickness of the feed/brine spacer. Either enhancement could be selected depending on the quality of the feedwater or the efficiency of the pre-treatment. However, it was not possible for the system designer to capitalize on the benefits associated with both enhancements. For this reason, when treating high quality source water, system designers prefer to use spiral elements that contain higher surface area to realize lower capital cost or lower operating cost. When treating high fouling source water such as municipal wastewater, RO designers have utilized the thicker feed/brine spacer to reduce differential pressure losses, minimize fouling and improve cleaning effectiveness. Designers selecting elements with thicker spacer forfiet the benefits associated with higher area elements. In recent years, thanks to innovations in material science, a new generation of RO elements are now being operated in full scale plants. These elements offer both a larger surface area and thicker feed/brine spacer.
This paper will detail the innovation in the construction of the new membrane material and compare its effects on element performance with previous generation membranes. The paper will analyze the operation of these new elements in at least two different applications including municipal wastewater reclamation and treatment of seawater on an offshore oil platform. Based on the operation of these new elements, a capital and operation cost comparison will be made with similar plants operating with the older generation of membranes.
2:15pm IWC 21-22: Extracting Lessons Learned from a Coal Mine Impoundment Desalination Water
Tom Imbornone and Ken Robinson, Avista Technologies, San Marcos, CA
Wastewater treatment is becoming more prevalent across the globe. The complexity of the water treatment systems are also increasing as a result. When the wastewater to be treated is sent to an impoundment first, there is higher variability to the organics and solids level. It is especially challenging when this impoundment is also composed of seawater, as in the case discussed in this paper. Typically, the goal of a water treatment system is to achieve the desired product water quality at the minimum total cost. Sometimes this mistakenly results in a lower capital system cost at the expense of increased operating costs for the final water treatment system.
This paper will discuss a water treatment system in the Midwest where the capital system’s robustness was sacrificed to the point where operational costs became much higher than desired. The main components of the system were originally a settling basin, multimedia filters (MMF), and two stage seawater RO’s. Membrane life was short resulting in an upgrade of the MMF’s to an Ultra-Filtration (UF) system. The system also struggled with scaling of the RO’s. We will dive into the critical aspects of where this system was/is deficient and cover alternatives to the choices made.
Specific topics the paper will discuss are as follows:
- Particle count requirements ahead of an RO
- MMF performance issues
- Break tank considerations
- The importance of purified water during UF clean in place
- Impact of water temperature on scaling and antiscalant dosage
The goal of this paper is to help guide a future owner or operator of a water treatment system so that they have a better understanding of some of the problems and risks in treating impoundment water.
3:20pm IWC 21-23: Advanced Wastewater Treatment in Textile – An Overview of Bangladesh Region
Harkirat Kaur and Thentral N., SUEZ Water Technologies & Solutions, Bangalore, Karnataka India; Craig Van Dyke and Joshua Dewanaga, SUEZ Water Technologies & Solutions, Bellevue, WA
The Textile Industry is among the most water consuming industries. It takes about 20,000 liters of fresh water to make one pair of jeans and a t-shirt. Consequently, significant quantities of wastewater containing a variety of harmful chemicals is generated. Bangladesh, which is one of the world’s largest apparel exporter, generated approximately 280 million cubic-meters of wastewater in year 2019. The majority of the existing water treating plants in Bangladesh have used conventional treatment schemes which involved physical-chemical conditioning (occasionally) followed by biological processes. But increasing space constraints coupled with soaring demands for textile units expansion called for a compact and robust water treatment solution. Moreover, following the zero discharge of hazardous chemicals (ZDHC) guidelines, textile units pivoted to operate more sustainably by reducing their chemical consumption for pre-treatment while meeting the stringent discharge limits.
Membrane Bioreactor (MBR) processes, which combines biological treatment with submerged Ultrafiltration membranes, provides significant advantages over the conventional treatment process. It avoids the use of hazardous chemicals and is an ideal technology for generating water quality suitable for further treatment using reverse osmosis (RO) to enable wastewater recycling and reuse, which is the next key focus of Bangladesh region. This paper will discuss how MBR achieves improved water quality (in terms of COD, BOD, TSS and Color) for the treated water being discharged from different textile processing applications such as (i) Knit Dyeing, (ii) Yarn Dyeing, (iii) Denim/Woven Dyeing, and (iv) Denim Washing.
The development process for designing MBR solutions starting from lab studies to site operations will be presented along with operational data to validate performance over conventional water treatment schemes. In addition, key learnings will be discussed which resulted in equipment design improvements (i.e. size reduction) and to improve processes for removal of threads/fibers, and to reduce dye coloring the final effluent stream for discharge.
4:10pm IWC 21-24: 99% Recovery RO Membrane System Demo Plant Results: Cooling Tower
Derek Mandel, Dayle Gill, and Geer Qile, Saltworks Technologies, Richmond, BC, Canada
Results and performance data of a 60-day on-site pilot treating cooling tower blowdown (CTB) at up to 99% recovery with a membrane system are presented. The ultra high recovery reverse osmosis system alleviates the need for a thermal evaporator or wastewater trucking to a discharge facility, leaving a 1% brine by volume to be managed by a small legacy evaporation pond. This work builds on past IWC papers that originally presented the high recovery technology. The focus of the paper is to share knowledge and lessons learned with water treatment plant designers and operators to enable successful high recovery membrane systems on highly scaling waters.
The pilot project was completed in 2020 at Nutrien’s ammonia fertilizer production facility in Alberta, Canada. The CTB feedwater contained membrane fouling surfactants, calcium sulfate and silica scaling ions. The project technology included scaling ion removal via precision controlled chemical softening without using coagulants. Chemical softening solid by-products were filtered using self cleaning ceramic ultrafiltration. Desalination was accomplished by two stages of reverse osmosis rated for 1200 psi (SWRO) and 1800 psi (UHPRO). The plant achieved continuous, reliable, and automated operation reaching 99% recovery, including unattended overnight operations and automated membrane health protective actions.
Ultra high recovery reverse osmosis systems are becoming increasingly important to industry, with a range of applications. Specific to this project, the US Department Energy estimates that cooling towers consume 54% of America’s freshwater resources – more than agriculture. Treating CTB is becoming increasingly important as legacy evaporation ponds fill, water volumes become harder to manage, limits become tighter on CTB used for land application or sewer discharge, regulations evolve to increase water re-use, and global corporations aim to reduce their water footprints. This work focuses on the next generation of CTB water recovery, for example taking a membrane system from a typical 80% recovery to 98-99% recovery – a twenty-fold decrease in brine volume without need for a thermal system. The results translate to other applications including mining and factory wastewater, flue gas desulfurization (FGD), lithium extraction, indoor faming, bio-energy wastewaters, and oil and gas.
This paper shares the system process flow and mass-energy balance data, including water chemistries for feed, permeate, and concentrated brine. The data is currently being used to design a first full scale plant. The reader should gain a solid understanding of ultra high recovery membrane system design and performance expectations for scaling industrial wastewaters.
Monday, 11/8/2021; 1:15 PM
M8-ASME Boiler Guideline Revisions and Related Topics
IWC Rep: Wayne Bernahl, W. Bernahl Enterprises Ltd., Elmhurst, IL
Session Chair: Ken Kuruc, Hach, Perrysville, OH
Discussion Leader: Jerry Jones, Ecolab, Sugar Land, TX
ASME feedwater and boiler water guideline revisions will be presented and discussed by a panel of ASME committee members along with several other boiler operating topics. Discussions will focus on improving the efficiency of and minimizing combined water and energy consumption in the steam/water cycle, silica deposition and fouling with corresponding methodologies to assure steam purity, and a secondary additive to enhance the performance of traditional film-forming amines.
1:25pm IWC 21-25: Amine-based Filmer Chemistry for Boilers with Improved Water Solubility and
Mahesh Budhathoki, Donald Meskers, Jr., Claudia Pierce, and Gregoire Poirier Richer, SUEZ Water Technologies & Solutions, Trevose, PA
Film forming chemistries have increasingly found use in steam generating systems over the past years. The system operator is often challenged to select between a non-amine filming material with limited corrosion protection and an amine-based material with stronger protection but some potentially undesirable properties and/or effects such as poor water solubility, steam condensate deposit formation, increased cation conductivity contribution, and so forth. In this work, a secondary additive was evaluated as a method to mitigate the challenges of an existing amine-based filming chemistry. Laboratory evaluation of a target formulation using a combination of custom research boilers, pressure vessels, and standard electrochemical techniques revealed that the added component not only affects the filmers’ steam partitioning properties but also minimizes both system fouling propensity and cation conductivity contribution while enhancing overall corrosion performance. X-ray photoelectron spectroscopy (XPS) was utilized on laboratory filmer coated passivated steel test specimens to evaluate the impact of the secondary additive on the composition and nature of the protective film. Initial results of field applications of the modified filming chemistry are discussed and correlated with the results of laboratory testing.
2:15pm IWC 21-26: Doing More with Less: Optimizing the Industrial Boiler Steam/Water Cycle
Colleen Scholl, P.E., HDR, Whitewater, WI
Steam remains essential to operation in most industrial facilities today accounting for nearly 30% of the process energy consumption utilized in the US manufacturing sectors. Some industries are larger steam users than others; for instance, based on the latest Manufacturing Energy Consumption Survey (MECS) released at the end of 2017, the amount of steam, as a percentage of the total energy consumed, utilized by the pulp and paper industry is 83%, by the chemical manufacturing industry is 57%, and by the petroleum refining industry is 42%. In many instances, this steam is injected directly into plant processes, loss via leakage, vented to atmosphere, or discarded via blowdown. Given this data, opportunity exists to optimize operations and address sustainability initiatives by combining goals for energy and water efficiency.
This paper will describe the water and energy balance that exists in typical industrial steam/water cycles. It will discuss and assess various opportunities for improving efficiency and minimizing combined water and energy consumption through the implementation of chemical control options, water quality improvements, water recovery and reuse, system upgrades or retrofits, and modification of operational practices. Tradeoffs and payback period for several sample cases will be detailed and presented.
3:20pm IWC 21-27: Overview and Panel Discussion on Consensus on Operating Practices for the Control of Feedwater and Boiler Water Chemistry in Industrial and Institutional Boilers
Robert Bartholomew, P.E., sheppard t. powell associates llc, Baltimore, MD; Tony Banweg,
A Virtual panel discussion is proposed by members of the ASME Research & Technology Committee on Water and Steam in Thermal Systems to discuss the Consensus on Operating Practices for the Control of Feedwater and Boiler Water Chemistry in Industrial and Institutional Boilers. Significant revisions of this consensus document are nearing completion in the committee. These presentations and the associated panel discussion is designed to explain the new consensus, what has changed and why those changes were implemented.
Presentation 1: Introducing the Revised Consensus on Operating Practices for the Control of Feedwater and Boiler Water Chemsitry, Robert Bartholomew
This presentation will provide a general overview of the consensus document by the Committee Chair and will include the following:
- Introduce the Consensus Guidelines and the Process for Their Development
- Outline the Current Consensus
- Discuss what it contains and what is new
- Discuss what it does not contain.
Presentation 2: Understanding Carryover Estimates and Boiler Water Conductivities, Anton Banweg
This presentation will focus on correcting misleading or incorrect information in prior published guidelines from the perspective of a former boiler manufacturer previously involved with setting boiler guarantees, ABMA limits and ASME consensus limits. This will explain how boiler water limits were calculated based on previously agreed boiler manufacturer guarantees and selected steam total dissolved solids (TDS) targets.
Presentation 3: Understanding Silica and Alkalinity Consensus, Edward Beardwood
This presentation will explain the streamlined process in the new Consensus document for setting boiler water silica limits to achieve common steam silica limits. The presentation also will discuss silica limits designed to prevent silica deposits in boilers and the basis for alkalinity guidance included in the Consensus document.
Presentation 4: Understanding Steam Purity Limits, James Robinson.
This presentation will discuss the rationale for the range of steam purity values included in the document from the perspective the Chair for A Practical Guide to Avoiding Steam Purity Problems in the Industrial Plant published in 1995 (and one of the two remaining members of the Committee that worked on the very first ASME Consensus document published in 1979).
4:10pm IWC 21-28: Understanding Silica and Alkalinity ASME Consensus for Industrial Steam
Edward Beardwood, Beardwood Consulting & Technologies Inc. (BC&T Inc), London, ON Canada
[Presentation 3] Silica present as an impurity in waters used for the production of steam have resulted in both water side deposition in steam generators and steam/condensate fouling within turbines. A brief review of the history of silica deposition/fouling and its control will be provided. The suggested boiler water silica limits in the new ASME booklet; “Consensus on Operating Practices for the Control of Feedwater and Boiler Water Chemistry in Modern Industrial Boilers” , and their derivation will be discussed. The elements comprising total steam purity as well as a procedure for estimating the silica contribution will be disclosed. The effects of silica volatility and prediction methods will be provided. This then allows one to determine the steam generation system operational control range set points required to meet the silica steam purity specification associated with a particular turbine and its duty. Emphasis on the methodology used to avoid silica deposits within steam generators and fouling of steam turbines will be outlined. To illustrate the process; an example calculation is provided in the paper.
Tuesday, 11/9/2021; 8:00 AM
T1-Industrial Wastewater Treatment
IWC Rep: Tom Lawry, McKim & Creed, Inc., Sewickley, PA
Session Chair: Ed Greenwood, Wood, Chantilly, VA
Discussion Leader: Christine Piekarz, HDR,
For industrial wastewater, treatment challenges continue to be wide ranging and multifaceted. For many industries with complex waste streams treatment can be especially challenging. As well, the ELG discharge requirements are evolving; becoming more site specific and more practical which will drive the need for specialized treatment solutions. In this session, we will explore these growing trends and discuss several new innovative treatment strategies rising to the challenge. Papers will examine the obstacles facing industry and some new approaches when treating complex high strength wastewaters.
8:10am IWC 21-29: Developing Reasonable Best Available Technology Discharge Limits for Bottom Ash Transport Water Purge Allowances for Operational Coal-Fired Electric Generating Units
Lindy Johnson, Stantec, Chattanooga, TN; Adam Sutherland, Stantec, Nashville, TN; Bill Kennedy, Stantec, Charlotte, NC
EPA declined to promulgate national Best Available Technology (BAT) discharge limitations for bottom ash transport water (BATW) purges from high-recycle systems in the 2020 Steam Electric Effluent Limitations Guidelines (ELGs). Instead, EPA determined that each site’s ELGs for BATW purge discharges at coal fired plants that continue to operate would be established on a site-specific basis using Best Professional Judgement (BPJ). BAT established by BPJ should follow the same statutory factors that EPA uses in a national ELG rulemaking, only this time the factors should be applied at each site. Many sites may have to either prepare, review, or support their regulators in establishing the ELGs by BPJ in order to achieve reasonable limits on discharges of BATW.
Purge discharges of up to ten percent of the wetted surface of primary BATW components are allowed on a 30-day rolling average in high-recycle BATW systems. These purge streams may be needed in order to prevent corrosion, scaling, water imbalances from excessive inflows, or fines buildup in high-recycle systems. This paper describes steps to establish technically defensible BAT discharge limits by BPJ that result in reasonable treatment approaches and costs, including the possibility of required process modifications.
EPA’s regulatory guidance for permit writers indicates that a series of steps should occur to establish BAT by BPJ. These steps include wastewater characterization to establish constituents of concern and potential use of indicator pollutants, appropriate statistical analyses, descriptions of the age of equipment and the process employed, engineering aspects of various types of pollutant control techniques, costs or affordability of achieving limits, and non-water quality environmental impacts including energy requirements. This paper describes these steps and offers recommendations on how to proceed for an example case study.
Diane Martini, Burns & McDonnell, Chicago, IL
9:00am IWC 21-30: FGD Scrubber Ferrous Injection and Sulfite Control to Achieve ELG Limits
Thomas Higgins, Worley, St. Augustine, FL; Michael Rogero and Troy Patton, Seminole Electric Cooperative, Inc., Palatka, FL; Mary McCloud, Worley, Ft. Lauderdale, FL
In October 2020, the United States Environmental Protection Agency (EPA) issued final revisions to the 2015 Steam Electric Power Generating Effluent Guidelines (ELGs), with regulatory changes for flue gas desulfurization (FGD) wastewater with stringent limits for mercury, selenium, nitrate and arsenic.
Modern forced oxidation FGD scrubbers operate with excess air to fully oxidize sulfite to sulfate and achieve SO2 removal requirements. This results in a scrubber slurry with a high oxidation reduction potential (ORP), which results in selenium being oxidized from selenite to selenate and causes mercury re-emission.
Selenite (but not selenate) can be removed from FGD wastewater through co-precipitation with ferric hydroxide in a typical physical and chemical treatment system. BAT achievement of FGD ELG limits is based on phys chem treatment with biological treatment and ultrafiltration for selenium removal.
The principal author of this paper found that soluble arsenic, selenium and mercury in FGD wastewater was related to particulate iron, and postulated that the addition of ferric iron solutions to a scrubber would result in precipitation of these metals before they can be oxidized in the scrubber. This led to a lab scale test followed by two full scale tests on scrubbers that showed that ferric injection reduced these soluble metal concentrations in the scrubber blowdown.
Seminole Electric installed sulfite monitors in their Palatka plant to control oxidation air which has resulted in reducing concentrations of soluble selenium and mercury in their scrubber purge which is treated via ferrous reduction of selenium and iron co-precipitation. Ferrous addition also was found to be effective at reducing nitrite and nitrate concentrations to achieve ELG limits.
Seminole’s sulfite control is limited by ability to turn down oxidizing air to the scrubbers. Worley suggested that Seminole consider injecting ferrous iron salts directly into the scrubber modules, to assist with sulfite control, to tie up selenium, mercury and arsenic, and to reduce nitrite and nitrate, producing a purge that could achieve ELG limits with just TSS removal.
Seminole initiated a partial scale test which showed promising performance removing arsenic and selenium. Since 1 of 8 modules was treated, recycle flows from the other untreated modules allowed oxidized selenium to return to the treated module. As a result, Seminole initiated a test where ferrous iron was injected into all modules, which improved performance on treatment of arsenic, selenium, mercury, nitrate and nitrate. Our paper will present the results of testing to date.
10:20am IWC 21-31: Sulfolane Treatment: Adaptive Approach using a Moving Bed Bioreactor
Srinivasa Varadhan and Janet Goodfellow, Geosyntec Consultants International, Guelph, ON, Canada; Scott Forbess and Richard Hodges, Geosyntec Consultants, Inc., Rancho Cordova, CA
Moving bed bioreactor (MBBR) technology was adapted for a unique groundwater treatment application to treat sulfolane, a currently used petrochemical and manufacturing industry solvent, and a contaminant of emerging concern in groundwater at several industrial facilities. This paper presents a case study on the comparison of sulfolane treatment technologies and testing, scale-up, and performance of a sulfolane treatment MBBR system to manage the complexity and cost to operate an existing fixed bed bioreactor at the facility.
Microcosm, bench-scale, and field pilot testing data were used to scale-up the MBBR design for a typical groundwater profile with low organic and nutrient loading rates. The microcosm and bench-scale studies successfully demonstrated sulfolane degradation using inoculum obtained from an existing fixed bed bioreactor. The completely mixed flow-through pilot system showed that more effective sulfolane removal is achieved by fixed-biofilm microorganisms on inert MBBR media as opposed to suspended growth microorganisms. Pilot system performance was optimized by balancing the quantity of MBBR media with hydraulic retention time (HRT) to optimize the size and cost of the full-scale system. Sensitivity analysis of the pilot system was performed to assess potential operational limitations during scale-up. The pilot system demonstrated low sensitivity to nutrient requirements due to relatively low carbon loading. However, decreased sulfolane degradation kinetics resulting from low microbial activity were observed at temperatures below 60F, with rapid recovery at 70F or higher. DO concentration ranging from 6 to 10 mg/L was determined to be optimal for sustained performance. The pilot system was able to consistently and reliably degrade sulfolane concentrations of more than 2,000 micrograms per liter (ug/L) to less than the 3 ug/L laboratory detection limit using an HRT ranging from 6-8 hours. The pilot system was scaled up to a successfully operating MBBR system utilizing 30% MBBR media by volume and an overall HRT of 8 hours operating at a peak flow rate of 600 gpm for up to 2,000 ug/L sulfolane. The need for a fixed-biofilm substrate, sufficient HRT, and an optimal operating temperature range and DO concentrations were determined to be the key parameters for this system.
11:10am IWC 21-32: Detecting Ammonia-Ammonium Accurately in Produced Waters
Kishor Nayar, Ph.D., Holly Churman, P.E., and Chris Benjamin, GHD Inc., Houston, TX
Produced waters in several oilfields in the USA regularly encounter total ammoniacal nitrogen (TAN) levels (100-1000 mg/L) much higher than EPA’s surface water quality chronic criteria for TAN (1.9 mg/L). When waters from different oil fields mix, pH and salinity fluctuations can lead to ammonium converting to ammonia and strong ammonia odors evolving from produced water. Managing ammonia-ammonium in produced water requires first answering a few key questions: What analytical methods (EPA 350.1 vs. Standard Method 4500-NH3) could be used for detecting ammonia-ammonium in produced water and what are their limitations? How can ammonia-ammonium be detected in the field? How do you obtain concentrations of ammonia or ammonium after testing for the other? Which ammonia-ammonium relationships could be accurate for produced water? The latter question is particularly difficult given equilibrium data in the literature for ammonia-ammonium (i.e. pKa data) in saline waters is limited to seawater salinity of 45 g/kg . In this paper we report our answers to these questions, highlight sources for operational errors and present a simple framework for oil and gas operators to use. Results reported are expected to help both oil and gas operators and water treatment companies around the world to better detect and manage ammonia concentrations in produced water.
Tuesday, 11/9/2021; 8:00 AM
T2-ZLD & Brine Management
IWC Rep: Jane Kucera, Nalco Water, an Ecolab Company, Naperville, IL
Session Chair: Wayne Bates, Hydranautics, Rockton, IL
Discussion Leader: Jordan Pearce, P.E., OLI Systems, Houston, TX
Minimum Liquid Discharge (MLD) and Zero Liquid Discharge (ZLD) systems are becoming more popular as industry drivers incentivize maximizing water recovery and minimizing disposal volumes of liquid concentrate (brine). This session reviews current concentration and disposal methods, with an emphasis on the use of RO membrane technologies upstream of evaporators, crystallizers, centrifuges, ponds, and other evaporation methods. We consider these upstream membrane processes to be MLD processes, since recovery can be limited to 90-97% of the feed, and not ZLD processes, which require 100% recovery.
8:10am IWC 21-33: Xcel Cherokee near ZLD Wastewater Treatment System Design Considerations
Paul Brandt, Burns & McDonnell, Kansas City, MO; Bryan Hansen, Burns & McDonnell, Denver, CO; Adam Kortan and Jason Miller, Xcel Energy, Denver, CO
The Xcel Cherokee Generating Station in Denver, Colorado was recently given new NPDES permit limits for chlorides, sulfates, total inorganic nitrogen (TIN) and other constituents for the plant’s common outfall. Meeting the new chloride and sulfate concentrations became the limiting factor for technology selection and compliance. Wastewater produced at the plant includes cooling tower blowdown, reverse osmosis (RO) system reject, stormwater, and other miscellaneous plant wastewaters. Due to the new NPDES limits, Xcel Energy, with the assistance of Burns & McDonnell, determined that a near-ZLD wastewater treatment system was the best option for the plant to replace an existing conventional clarification system. Treated water from the new system is returned to the plant for reuse and concentrated brine is routed to new evaporation ponds. Various options were evaluated in the study phase to help select the most economical treatment configuration including: Makeup water softening, High efficiency reverse osmosis, Nanofiltration, Closed-circuit reverse osmosis, Forward osmosis, Ultra-high pressure reverse osmosis, Membrane electrodialysis, Osmotically enhanced reverse osmosis, Mechanical vapor recompression evaporator, Forced circulation crystallizer, Alternative thermal evaporator designs, Evaporation ponds, Waste heat cooling tower, Bypass evaporator spray dryer, Operational changes, Discharge to a nearby POTW facility
The wastewater system ultimately selected and designed includes:
Equalization ponds, High rate softening clarification, Multimedia filtration, Closed circuit reverse osmosis with 98% recovery of wastewater for reuse, Evaporation ponds for concentrated brine wastewater, Filter press for sludge dewatering, Required startup in Fall of 2021
The WWT project is currently under construction and is planned to complete startup at the end of 2021. This paper will cover the following aspects of the study and detailed design phases of the wastewater treatment system:
- Study phase options considered and drivers for the near ZLD system selected.
- Process description and design considerations/limitations of equipment selected.
- Operational changes to reduce wastewater flow requiring treatment.
- Challenges of elevated TOC in wastewater, effects on selected wastewater equipment, and TOC removal methods evaluated.
- Challenges and recommendations of locating new equipment in existing water treatment building
- Methodical approach to evaporation pond selection/sizing.
9:00am IWC 21-34: Power Plant Water Balance Tool Optimizes Load Leveling and Achieves ZLD
Dan Carey, Ph.D., P.E., Worley, Charlotte, NC; Tom Higgins, Ph.D., P.E., Worley, St. Augustine, FL; Eric Costello, Tom Gaboian, and Nate Parker, Orlando Utilities Commission, Orlando, FL
Orlando Utilities Commission (OUC) operates two coal fired boilers in the Stanton Energy Center. OUC has recently announced they will repower both units with natural gas in 2025 and 2027. The plant is a zero-liquid discharge (ZLD) facility. The repowering will bring its own challenges to the ZLD operation. During periods of high net rainfall (particularly the summer) water levels in wastewater storage ponds are limited by evaporating water in the FGD scrubbers and disposal of gypsum. If the plant’s units are not operated at sufficient capacity factors, FGD scrubber evaporation and gypsum disposal are limited.
OUC had a need for a water balance model that could be operated by onsite personnel. There were several goals for the model including:
- Forecasting future conditions to guide dispatch and maintain ZLD;
- Understanding the effects to the salt balance on ability to reuse water;
- Predicting flue gas stack evaporation and salt balance for coal firing and future transition to gas firing of boilers at varying capacity factors and combinations of coal and gas;
- Ability to update data with actual date for past operation to improve accuracy of future operations;
- A non-proprietary model that plant personnel can use without outside support;
- Simple inputs and operation.
A Microsoft Excel model was created to predict pond storage volumes, chloride and TDS concentrations. FGD evaporation is correlated to capacity factors, temperature, humidity, barometric pressure, and fuel properties. Evaporation rates for mixtures of coal and natural gas were calculated using an inhouse model and graphed for the non-proprietary model. The model includes use of reverse osmosis and evaporation for disposal of water and salts. Inputs include capacity factors, process flows, and constituents, rainfall, and environmental conditions. Several examples of model runs will be provided.
The model was calibrated with historical data; results confirm monthly flows and pond volumes are accurate to +/- 5% over a year. The user inputs 12 months of operating data to predict future conditions. The model offers monthly outputs and finer adjustments on operation. For example, FGD purge rate, gypsum cake solids water content, pond level control, and RO system operation may be adjusted for each month.
OUC has found the model useful in optimizing dispatch decisions and maintaining ZLD requirements. Methods used in this interactive water balance tool may be helpful for other facilities to maintain water balance across a system, track water quality for reuse applications, and test new operating conditions.
10:20am IWC 21-35: Increasing Productivity of an Existing RO Plant BY Reducing the Rejected Brine
Boris Liberman, Gal Greenberg, and Lior Eshed, IDE Water Technologies, Kadima, Israel
The approach to the design of Brackish Water RO (BWRO) plants is changing radically throughout the world. Until now, the design of RO recovery was based on reaching the limit of permissible scale formation by dosing antiscalant in steady state operation. The new approach allows significantly increasing the recovery of BWRO by the implementation of two elements – induction time and fast and frequent online membrane cleaning.
Induction Time – is defined as the time between the formation of an appreciable amount of the solid phase and the initial moment of supersaturation of the solution. In Batch or semi Batch RO processes the raw solution may be quickly concentrated to high supersaturation and discharged from the membrane before Induction Time ends for this batch of raw solution. An RO process that can concentrate the solution more quickly, and remove it from the membrane, can achieve higher recovery without scaling. The new Pulse Flow RO (PFRO) technology, which will be described in the paper, is completely contrary to conventional RO operation – the flow is not stable, the osmotic and gauge pressure change frequently and rapidly. The Production-Flushing cycle, where the raw solution is squeezed and discharged, is extremely short, which allows reaching the highest recovery.
Fast And Frequent Online Membrane Cleaning – Induction time is not a fixed value, but a Gaussian distribution. This means that some crystals will be formed in significantly less time than the “mean account” Induction time. A tiny amount of scaling might form on the membrane, and this should be removed using fast and frequent online membrane cleaning. This cleaning procedure will be described in the paper.
This paper will present a case study describing the performance of a pre-commercial unit installed to demonstrate the increase in productivity of the existing Abilene BWRO plant in Texas, USA, by reducing the rejected brine stream by a further 80%. The source is surface water originating in a lake. After three stages of RO and 80% recovery, the brine is accumulated in ponds. Because the volume of the ponds is limited, the brine is sprayed to increase evaporation.
11:10am IWC 21-36: Design & Operational Considerations for a ZLD RO Brine Treatment System
Sean Forsberg and Americus Mitchell, Sundt, Tempe, AZ
A zero liquid discharge brine treatment system was constructed to treat RO reject at an industrial wastewater plant in Arizona. The primary product of the system is a sodium sulfate salt. The system is composed of a falling film evaporator, forced recirculation crystallizer and pusher centrifuge for salt dewatering. During commissioning & start up issues related to the design of the plant became apparent, remedies to these issues are discussed in this paper and should be considered for future design of similar facilities. One of the major issues was the disposal of fine particles accumulating in the crystallizer system, which led to issues with the dewatering of the salt downstream. Other design issues discussed are boiler sizing, salt handling, locations for flush ports, distillate system design and valve choices. Feedwater characteristics & operational parameters such as flow rates, sump pH, antifoam dosing, by-pass operation, and operational data will be discussed in the paper.
IWC 21-T2R: Maximizing the Value of ZLD Technology
Lindsay Buhl, Aquatech ICD, Hartland, WI; Simone Callioni, Aquatech International, Canonsburg, PA
It’s been said that zero liquid discharge is the Holy Grail of water recovery and reuse in an industrial plant. Insomuch as it is a treasure to be sought after, this is true. Zero liquid discharge systems can provide environmental compliance for projects with challenging wastewaters, they recycle water for plants where water is scarce, and can reduce the overall carbon footprint of a plant. However, unlike the Holy Grail, these projects are no longer elusive and are being implemented in more and more applications. Each effluent stream in each application presents its own challenge and a successful ZLD design requires a careful assessment of several groups of technologies to deliver the optimal recovery strategy: the integration of complementary membrane and evaporative technologies being chief among them. These processes hold the key to optimizing capital and operating costs and, at the same time, to make ZLD both viable and valuable. This paper covers these concepts in theoretical detail with each concept supported by a real-world case-study. We discuss how: (i) the wastewater chemistry drives the selection of the best process, (ii) each Zero Liquid Discharge design is unique which leads to a contextualized diversity of solutions, (iii) achieving technical and commercial value simultaneously often involves a well-crafted solution from a suite of technologies.
Tuesday, 11/9/2021; 8:00 AM
T3-State of the Science: PFAS Treatability Review
IWC Rep: Mike Gottlieb, ResinTech, West Berlin, NJ
Session Chair: Kristen Jenkins, GHD, Duluth, GA
Discussion Leader: Eric Klinker, DuPont,
This session focuses on recent advances in PFAS treatment in water for a range of applications from drinking water to leachate. Conventional technologies (GAC and IX) are covered as well as research on the capability of over 10,000 organisms to biodegrade PFAS
8:10am IWC 21-37: Per- and Polyfluoroalkyl Substances (PFAS) in Landfill Leachate: Assessment, Forensics, Treatment and Management
Angus McGrath, Stantec, Walnut Creek, CA; Krista Barfoot, Stantec, Waterloo, ON, Canada; Janice Stonebridge, Stantec, Waterloo, ON, Canada; Ron Ruocco, Stantec, Charlotte, NC; Peter Daniels, Stantec, Golden Valley, MN
PFAS, a group of more than 3,000 human-made chemicals, are ubiquitous at very low levels in the environment, and have been measured in water supplies across the US. PFAS investigative efforts have historically been focused on the release of aqueous film forming foam; however, growing concerns regarding the potential for PFAS releases from other sites are prompting the expansion of that focus. On March 20, 2019, California’s State Water Resources Control Board released an order requiring PFAS investigations at landfills, identifying 196 sites for assessment. While, internationally, standards for allowable concentrations of various PFAS in different environmental media continue to evolve, guidance and regulation specific to the assessment of PFAS at landfill sites continues to lag.
Landfill leachate poses a significant challenge for PFAS removal because the other constituents in the matrix have a greater affinity for adsorptive surfaces of granular activated carbon (GAC) or ion exchange (IX) and inorganic species will also tend foul treatment systems. Emerging technologies have been shown to be effective at removing PFAS from landfill leachate that are compatible with GAC and IX, allowing post treatment polishing to achieve effluent standards by both. The resultant concentrated PFAS waste reduces the overall mass of solids requiring incineration.
This talk will explore the current status of developing standard industry practices for sampling PFAS at landfills, interpreting the results to identify potential sources, assessing potential risks, evaluating leachate treatment technologies, and identifying management options.
9:00am IWC 21-38: City of Issaquah, WA’s Experiences with PFAS Removal for the Past Six Years
Pierre Kwan, P.E., HDR, Seattle, WA; Robert York, P.E., City of Issaquah, Washington, Issaquah, Washington; Beth Mende, P.E., HDR, Bellevue, WA
This presentation shares details of how a water system implemented a treatment response after detecting per- and polyfluoroalkyl substances (PFAS). The City of Issaquah, Washington provides drinking water to its customers from groundwater wells. As part of federal mandated monitoring in 2015, the City detected PFAS in its 250 GPM Well No. 4. PFOS was detected at concentrations as high as 600 ng/L, 8.5-times higher than the USEPA Lifetime Advisory Level of 70 ng/L for PFOS+PFOA and 40-times higher than the pending State action level of 15 ng/L. The City immediately reviewed the situation and selected wellhead treatment to handle the situation. The entire system was designed, permitted, constructed, and started up in 77 days. The facility started operations in June 2016. At the time of this presentation, the system has been in continuous use for nearly six years and is one of the longest continuously operating PFAS removal systems in the world. This presentation discusses the operational surprises, challenges, and unintended consequences that the operators has dealt with over this time.
Two vertical granular activated carbon (GAC) vessels were installed in lead/lag configuration, with more vessels planned in future expansions. Given the project implementation speed, the project took the unusual step of installing one type of GAC media in the lead vessel and a second type of GAC in the lag vessel. The intent was to exhaust the lead vessel to determine the amount of PFOS removal, then switch to the lag vessel to quantify the second vessel’s performance. This operation allowed determination of which media provided the best dollars per gallon treated that the owner would use for future GAC replacement.
Operational insights that the City has gained include large differences between predicted and actual performance and operating costs, the media becoming radioactive despite the water having non-detectable radiation, frequent bouts of biological fouling, and ongoing regulatory issues with media disposal. In addition, while the full-scale GAC system was operating, we pilot tested ion exchange (IX) resins to determine if switching to IX would provide lower operational costs. The IX testing showed great promise in terms of quality but failed due to biological fouling. Potential solutions to allow IX to operate successfully were deemed financially infeasible and operationally complex versus continuing with GAC. The intent of this presentation is to share the City’s lessons learned so that other users can be more successful in addressing PFAS treatment challenges.
10:20am IWC 21-39: Estimating Ion Exchange Capacities for PFAS/PFOS Compounds Using Isotherm and Mass Transfer Data
Dirk Steinhilber, Lanxess, Koeln, Germany
Estimating Ion Exchange Capacities for PFAS/PFOS Compounds Using Isotherm and Mass Transfer Data
Ion exchange has been shown to be a highly effective method for the removal of PFAS/PFOS compounds down to concentrations that meet even the most stringent current regulatory levels. In addition, excellent kinetics and capacity for these compounds, using specially developed ion exchange resins, results in a process design that uses a very low empty bed contact time (EBCT) for the effective removal of these compounds. This kinetic efficiency combined with high-capacity results in both capital and process economies over alternative removal methods such as granular activated carbon.
One challenge in assessing ion exchange resin types for these family of compounds is the very low concentration of the contaminants which, along with the high capacity of selective resins, results in extremely high throughputs making laboratory or field column testing very time consuming.
This paper describes laboratory studies using industry accepted methodologies that experimentally derive isotherm rate kinetics and mass transfer coefficient for a particular contaminant and resin which may then be used to predict breakthrough curves and operating throughput.
Using these with well documented adsorption models, such as Langmuir & Freundlich, we are now able to provide a good estimate of operating capacities of ion exchange resins for various PFAS / PFOS compounds
The paper also compares, using the aforementioned methodology, a number of industry available selective resins promoted for the removal of PFAS/PFOS compounds .
11:10am IWC 21-40: Approach to Identify Optimal Enzymes for PFAS Biodegradation
Dayal Saran and Kent Sorenson, Allonnia, Boston, MA ; Micah Shepherd and Dave Young, Ginkgo Bioworks, Boston, MA; Michael Warady, Allonnia, Boston, MA
Per- and Polyfluoroalkyl substances (PFAS) are a family of persistent, toxic compounds commonly found in consumer products like cookware, food packaging, and firefighting foams. PFAS manufacturing facilities and airports, and military installations that use firefighting foams include some of the main sources of PFAS found in air, soil, and water and particularly sources of drinking water. Studies indicate that PFAS compounds can cause reproductive and developmental, liver and kidney, and other immunological diseases.
The EPA is leading the national effort to reduce PFAS risks to the public through implementation of its PFAS Action Plan and through active engagement and partnership with states, industry groups and local communities. Current solutions for PFAS remediation are focused on sequestration techniques via adsorption media and then transfer to a landfill or incineration facility. However, such solutions are insufficient in that they are merely transferring PFAS compounds to other media, of have emissions risks, instead of permanently destroying PFAS with no emissions.
Currently, various technologies are under development that are focused on complete destruction (defluorination) of PFAS compounds. Some of those technologies such as plasma-based destruction, sonolysis, electrochemical oxidation, and supercritical water oxidation are shown to be promising but tend to be energy intensive, expensive or impractical at desired scale.
Biological remediation could represent a simple, environmentally safe and cost-effective technology to treat PFAS-contaminated sources. While to date there are no examples of successful PFAS bioremediation, there are several publications from research labs showing degradation and defluorination of PFAS from bacterial and fungal microbes isolated from contaminated sites. We are expanding the search into microbes capable of degrading PFAS compounds. After a review of current literature and discussions with experts in the field of bioremediation, we are focusing on two family of enzymes, “ligninolytic oxidoreductases” and “reductive dehalogenases,” for their potential towards development of PFAS degrading enzymes.
In this presentation we will describe our approach to screen a total of around 10000 natural variants of Ligninolytic Oxidoreductases and Reductive Dehalogenases in a High Throughput (HTP) format to identify the most optimal enzymes capable of degrading PFAS. The next step will be to engineer the best strains for optimal activity under environmental conditions. We will also discuss the development of a novel HTP fluorine monitoring assay which is an improvement on current standard methods (IC or LC-MS) that are expensive and time-intensive and not HTP.
Tuesday, 11/9/2021; 8:00 AM
T4-Modeling & Measurement
IWC Rep: Colleen Scholl, HDR, Whitewater, WI
Session Chair: Brad Buecker, ChemTreat, Lawrence, KS
Discussion Leader: Chip Westaby, Turner Designs Hydrocarbons, Fresno, CA
Critical to proper chemistry control of industrial water and steam systems is accurate measurement and data analysis of process conditions. This session, from four industry experts, offers a broad overview of measurement and modeling techniques for cooling water, high-purity makeup water, and wastewater effluent to optimize internal plant processes and to ensure that plant wastewater discharge streams meet environmental guidelines.
8:10am IWC 21-41: Hardness and Alkalinity Revisited: A Novel Solution for Control Utilizing the Langelier Saturation Index
Ken Kuruc, Hach, Perrysville, OH
The presence of calcium and magnesium, along with other ions such as iron, strontium, aluminum, zinc and manganese, have caused issues in industrial water loops for decades. Not only are these cations responsible for scaling and restrictions in piping, they can diminish heat transfer capacities so critical to many of these loops. In the past, while sites have relied on laboratory testing and/or on-line monitors/analyzers for hardness and alkalinity, control could still be somewhat elusive.
The Langelier Saturation Index (LSI) is another tool available to water treaters to help in managing hardness and alkalinity, yet it is often not fully utilized or understood. In this review, the LSI will be discussed in terms of hardness, alkalinity, pH and total dissolved solids (TDS). A general overview of the more common methods of softening in the industrial setting will be given in order to demonstrate the necessary techniques for controlling this parameter. The brief coverage will be limited to the more common methods of precipitation, ion exchange and reverse osmosis (RO), and will assume some prior knowledge of this area of water treatment.
Finally, a solution will be offered which will permit automation and control of hardness and alkalinity based on the LSI. Two different technologies will be discussed: colorimetric and titration. Advantages, concentration ranges and limitations for each will likewise be considered.
9:00am IWC 21-42: Predicting the Future: Forecasting Industrial Wastewater Characteristics and Optimum Treatment
Edward G. Helmig, Susan E. Ambler, Mary Beth Miller, and Patrick J. Cyr, Woodard & Curran, Wayne, PA
This paper describes the process developed for a predictive model and simulation of complex biopharmaceutical manufacturing processes used to produce monoclonal antibody (mAb) type therapeutic proteins (drug substance AKA “DS”). The focus of this work is forecasting both the untreated wastewater characteristics, compliance risks, resulting treatment requirements, and the final treated wastewater characteristics for the effluent that is generated by the manufacturing process. The model development involves using the bill of materials (BOM) for each DS, creating mass balances around the BOM and step by step manufacturing processes, and converting raw materials to pollutant equivalents (e.g. Perfusion media components to ThOD→COD→BOD). Pollutant masses are then fractionated into components (soluble vs particulate, biodegradable vs non-biodegradable, etc.). Since multiple processes can occur simultaneously or staggered in parallel, the production schedules are evaluated, probabilities are assigned, and the data is run through a Monte Carlo Simulation (MCS) software package. Compliance risks are then assessed, and treatment, whether using existing or recommended
technologies, is then evaluated using a standard Activated Sludge Model (ASM) with kinetic and stoichiometric parameters adjusted for biopharmaceutical wastewater characteristics. The result is a highly advanced MBR treatment system with RO and evaporators that is now (early to mid 2021) entering service. Design data is provide along with stoichometry and kinetics.
10:20am IWC 21-43: RO Membrane Protection Facilitated by Direct, Accurate, and Automatic Measurement of ULR Chlorine Residual
Vadim Malkov, Hach, Loveland, CO; Collin VanderZanden, Maxim Integrated, Beaverton, OR
Multiple studies showed that prolonged exposure of RO membranes to chlorine exceeding 38 ppb (based on 1000 ppm-hr over 3 years) is detrimental to the membrane structure and integrity, while absence of the disinfectant promotes biofouling and causes loss of recovery. To maintain this delicate balance, the membrane operators must be able to accurately monitor oxidant concentration and addition of dechlorinating agents, especially in the RO feedwater. It is also important to monitor cumulative exposure of the membranes to the oxidizing disinfectant to understand the membrane efficiency and lifespan. Currently, such monitoring and proportional addition of sulfite-based agents is mostly done with either grab sample analysis based on DPD, or in combination with continuous ORP measurement. It is well known that intermittent grab sample analysis leaves significant gaps in the monitoring and may suffer from the user technique, while the relative nature of ORP does not make it the method of choice.
Some facilities use process instrumentation for chlorine monitoring, which cannot deliver the desired result based on the current state of technology. There is a demand for a simple and reliable instrument able to measure chlorine residual at the lower end of the range in a substantially continuous manner with adequate accuracy. The method should be accurate below 30 ppb to ensure sufficient concentration of disinfectant to control biofouling and avoid under- or overfeeding the dechlorinating agent. Such kind of instrumentation would allow maintaining the health and longevity of the membranes at lower cost associated with additional cleaning and dechlorination.
An online analyzer using DPD technology, able to accurately detecting and quantifying chlorine concentrations in RO feed at below 30 ppb, was developed and tested at several facilities using membrane filtration. The new instrument that can be connected to the cloud service, automatically reporting the results every 150 seconds and calculating cumulative chlorine exposure, was exposed to RO applications ranging from drinking water, to reuse, to power and oil refining, to desalination and beverage production. One study was conducted at an industrial facility utilizing several RO racks and over 200 individual cartridges with GAC pretreatment and addition of metabisulfite to destroy extra chlorine residual in RO feedwater. This case demonstrated highly accurate results at minimal maintenance efforts and supported chemical and labor cost savings elucidated by the instrument with ROI in two years.
11:10am IWC 21-44: Predictive Modeling of FGD Wastewater Characterization to Plan for Future Fuel Flexibility
Adam Sutherland, and Josh Pendergrass, Stantec Consulting Services Inc., Nashville, TN; Mayra Giraldo, Stantec Consulting Services Inc., Atlanta, GA
When designing a wet FGD wastewater treatment facility at a coal-fired power plant, it is critical to consider the effect of coal variability on the composition of the wastewater produced by the scrubber. Plants typically require fuel flexibility to remain competitive. That potential variability in coal can have a tremendous impact on treatment equipment size, feed rates, materials of construction, and ability to meet regulatory limits. By modelling the combustion process, including emission control devices, it is possible to develop bracketed data for future FGD wastewater volume and characteristics. This consideration can help minimize future capital and O&M expenditures to meet the challenges of ever-changing coal sources and regulatory requirements.
This paper will examine the key coal characteristics which affect wastewater in a coal plant. It will focus on determining the fate of chlorides and trace metals regulated by the EPA’s 2020 Effluent Limitation Guidelines, which can affect treatment chemical selection and dosing system sizing. The discussion will also include performance and operational impacts of the various air emission control devices, including scrubber additives, the selective catalytic reduction (SCR) equipment, and electrostatic precipitators on FGD wastewater.
A chlorides and trace element model has been developed using partition coefficients published in the literature. Several case studies using the model are presented. This paper will compare model estimates with measured concentrations (chlorides, selenium, arsenic, and mercury) in key wastewater streams to demonstrate the utility of the model for developing bench and pilot scale testing regimens that address the anticipated future range of fuel blends at a power plant.
IWC 21-T4R: Holistic Approach to Sustainability and Resilience at WEGD Facilities
Ron Ruocco, Stantec, Charlotte, NC; Suzette Puski, Stantec, Providence, RI; Mayra Giraldo and Adam Sutherland, Stantec, Atlanta, GA; Lindy Johnson, Stantec, Chattanooga, TN
Wet flue gas desulfurization facilities are being challenged as never before, and are tasked by stakeholders with identifying and implementing projects that enhance sustainability and resilience of current processes and operations.
This paper will discuss a holistic approach to identify projects to promote costs savings and overall stakeholder peace of mind confirming sustainability and resilience of existing internal approaches currently implemented at a given WFGD facility and well as setting the stage for future beneficial projects.
- Predictive modeling of FGD wastewater to plan for future fuel flexibility
- Combining landfill leachate and WFGD wastewater treatment
- Optimizing DBA in FGD and impacts to FGD wastewater treatment
- Development and implementation of BAT limits for a manageable bottom ash transport water purge allowance
- Creating chloride sinks for high recycle FGD and use of EPA’s BAT
- Optimizing dust control while minimizing FGD wastewater
- Chloride wash techniques to enhance marketability of beneficially used materials
A “third eye” by seasoned practitioners within the coal steam station industry can provide stakeholder peace of mind and establish cost saving projects for sustainability and resilience.
Tuesday, 11/9/2021; 1:15 PM
T5-CCR Water Management – New Approaches and Recent Experiences
IWC Rep: Jonathan Shimko, McKim & Creed, Sewickley, PA
Session Chair: Riley Flowers Ph.D., Southern Company, Birmingham, AL
Discussion Leader: Kirk Ellison, ,
As environmental regulations have evolved, the coal power generation industry and those who serve to maintain the nation’s energy balance have been inspired with a new focus on power plant wastewater and coal combustion product management. Utilities are rethinking their wastewater management strategies. This session will present new approaches to coal combustion product landfill leachate and valuable case studies in handling bottom ash transport water and equipment wash water in the new regulatory environment.
1:25pm IWC 21-45: Considerations for Landfill Leachate Treatment in Existing FGD Wastewater
Matt Newhart, Stantec, Alpharetta, GA; Adam Sutherland, Stantec, Nashville, TN; Bill Kennedy, Stantec, Charlotte, NC; Lindy Johnson, Stantec, Chattanooga, TN
With a tightening regulatory environment regarding discharge of coal combustion residual (CCR) landfill leachate, it may be advantageous for owners to evaluate the use of onsite existing wastewater treatment infrastructure for landfill leachate treatment prior to discharge. Existing phys/chem wastewater treatment systems may have increased available capacity with coal-fired generation facing reduced demand.
This paper will examine the feasibility of the option of using existing FGD or other wastewater treatment facilities for treatment of landfill leachate and other additional wastewaters. Evaluations will be made in the context of CCR landfill post-closure requirements. Regulatory challenges and considerations will be explored including application of EPA’s combined wastestream formula. The paper will also review keys to developing a robust leachate wastewater design basis including predicting flow and leachate water quality. Appropriate collection, storage, and conveyance recommendations will be developed. Calculating combined influent quality while maintaining fuel flexibility is also explored. Finally, a comprehensive approach for evaluating capacity at existing wastewater treatment facilities will be provided, with emphasis on evaluating potential obstacles while maintaining wastewater treatment system redundancy.
2:15pm IWC 21-46: A Comparison of Measured Landfill Leachate Generation to Predictive Modeling
Cedric Ruhl and See Hoon Lee, Wood, Chantilly, VA; Kirk Ellison, EPRI, Palo Alto, CA; Ken Daly, Wood, Charlotte, NC
Changes in the US energy system and environmental regulations have led to the increasing use of dry landfills for management of excess coal combustion products. As a result, landfill water management and leachate treatment have been increasing in prominence. One of the first steps to understanding the effectiveness of landfill management practices and to designing leachate treatment systems is estimating the range of potential leachate volumes produced during operation. Precipitation as well as landfill design and management practices can dramatically change the volume of water that needs to be managed. The selected leachate treatment approach and operational costs will be influenced by the estimated quantity and quality of leachate generated; therefore, accurately estimating leachate generation rates and volumes will help utilities evaluate cost effective leachate treatment approaches for their site.
The authors developed a method for estimating leachate generation volume for the landfill life cycle based on design leachate generation rates, landfill geometry, and landfill filling rate. This method was used to estimate leachate generation volume over time for four CCR landfills; two of which receive CCR from energy production and two of which receive CCR from ash basin closures. The estimated leachate generation volumes were compared to actual measured leachate generation volumes to evaluate efficacy of the predictive method, effect of precipitation on leachate generation, and effect of operational practices including rain covers on leachate generation.
3:20pm IWC 21-47: Lessons Learned in Implementing Treatment of Bottom Ash Sluice from Conceptual Design through Start-up and Commissioning in 7 months
Chloe Grabowski, HDR, Missoula, MT; Julie Horan, HDR; Dan Sampson, HDR, Walnut Creek, CA
In response to the Coal Combustion Residual (CCR) Rules, coal fired power plants have closed or are in the process of closing their CCR-related surface impoundments. The impoundments provide for flow equalization and treatment (solids settling) of the bottom ash transport water and often various other plant wastewater streams prior to discharge. These impoundment also provide for storage of bottom ash and other settled solids. The impoundment closure date for many of these facilities is rapidly approaching promoting the need for creative solutions and an effective team work to achieve tight compliance timelines.
This paper will present a case study of a project at a large coal fired power plant in North America (approval is pending to disclose the facility name). The facility is required to cease sending bottom ash transport water and other plant wastewater flows to their CCR impoundment by April of 2021. The facilities best shot at achieving this very tight timeline was to implement a rental treatment system. This paper will cover the approach taken to pursue this timeline and discuss numerous hurdles encountered and lesson learned from conceptual design through start-up and commissioning.
4:10pm IWC 21-48: Lessons Learned Treating Outage Wash Wastewater for Coal Fired Utilities
David Donkin, UCC, Waukegan, IL
The coal-fired electrical utility sector is faced with the regulatory requirement to retire their coal ash sluicing ponds under the finalized Coal Combustion Residuals (CCR) regulation. Wet-to-dry ash handling solutions are being implemented throughout the fleet to allow ponds to come out of service. One area of wastewater treatment need that still remains, once the ponds are retired, is the management and treatment of boiler, air pre-heater, economizer and precipitator wash wastewater. Historically these washwaters were simply directed to the CCR pond along with other ash materials and basically diluted with other materials prior to discharge. This option soon will no longer be available. The primary constituents of concern are total suspended solids, iron, copper and other heavy metals, and pH control. In addition, outage wash wastewater presents unique challenges with respect to wide flow variations and contaminant loading changes throughout a wash. A variety of new solutions are being implemented throughout the fleet, including mobile systems, sedimentation basins, and retro-fit of existing ash handling wet-to-dry infrastructure. Lessons learned from approximately 2 years of managing wastewater from outage washes will be reviewed.
Tuesday, 11/9/2021; 1:15 PM
T6-Sustainability & Optimization
IWC Rep: Michele Funk, P.E., Bechtel Corporation, Reston, VA
Session Chair: Pat Randall, Aquatech International, Tampa , FL
Discussion Leader: Robert McCandless, P.E., Brown and Caldwell, Phoenix, AZ
Sustainability is the science of wisely utilizing resources today to improve their availability for future generations. Now more than ever, industry has both societal and corporate responsibility to improve their water footprint and optimize its use. This session will demonstrate smart ideas using innovative technology to improve the sustainable use of water while protecting this critical resource.
1:25pm IWC 21-49: Data Center Cooling and Water Management – A Holistic Approach
George Hollerbach, Geosyntec Consultants, Lyndhurst, NJ; Philip Benson, Jr., Geosyntec Consultants, Washington, DC
The digital footprint in the US is expected to double every two years. Water is a critical component of data center (DC) cooling – the Water Usage Effectiveness (WUE) is a metric that divides the annual water usage by IT power. Using an average WUE of 1.8 L/kWh, a 100-megawatt DC would have a water demand of about 1.1 million gallons per day. Simultaneous to DC growth, planners must anticipate that climate change, water scarcity and the growing population demand for water in different regions of the country will adversely affect water supplies and lead to water shortages. DC’s can improve water supply resiliency through diversification of supplies, water conservation, and water reuse. DC’s require a large cooling infrastructure. This water demand, evaporative consumption and wastewater generation — all of which can be millions of gallons per day is why water availability rights and security are critical factors in siting and operating large data centers. Water scarcity challenges and pricing risks require water resiliency programs to secure long-term uninterrupted water supply. These resiliency programs address reuse and resource sustainability, along with balancing energy consumption with water use. Very few DC’s report on total water discharge, recycling rates; or waters affected by discharge, runoff or withdrawal, and associated biodiversity impacts. Reporting will have to increase and be communicated more widely for a better understanding of not only data center water efficiency, but their overall environmental footprint and sustainability. This paper will focus on the optimization of the data center water footprint – a useful sustainability measurement of the quantity of freshwater consumed and polluted. The WF is divided into blue, green, and grey water footprint. Blue footprint covers the volume of freshwater (surface or groundwater) consumed. Green footprint covers the volume of rainwater captured, treated and diverted to the process to offset the blue footprint. The grey footprint is an indicator of water pollution and is defined as the volume of freshwater that is required to assimilate the load of pollutants given natural background concentrations and existing ambient water quality standards. Emphasis is placed on finding sources of grey water that can be treated and reused in DC cooling. Holistically, a sustainable solution would require more emphasis on increasing the green footprint through rainwater harvesting and other measures and treating and reusing the grey footprint, while offsetting the blue footprint.
2:15pm IWC 21-50: Central Valley California Utility Removes Cr(VI) with Insitu Stannous Generator
Vladimir Dozortsev and Rick Bacon, Aqua Metrology Systems, Sunnyvale, CA
Traditional treatment systems that address trace metal contaminants, such as hexavalent chromium and more, are historically associated with high capital and operating costs. As a result, technology innovations and forward-thinking solutions are needed to advance the clean and safe drinking water goals.
One such solution is a novel stannous generator that harnesses the power of tin, a highly effective chemical reagent. Tin, generally considered non-toxic, is an attractive reagent for trace metal remediation because of its reductive power and the insoluble nature of the reduced tin species, tin oxide (SnO2). This insoluble byproduct can simply be filtered out after treatment.
This system has been evaluated at a community in the Central Valley of California during a full-scale pilot demonstration that studied the efficacy of the technology to continuously reduce Cr(VI) to below 2 ppb. The well site has elevated Cr(VI) levels of 40 ppb and extremely challenging water composition due to the presence of uranium, selenium, sulfates, high TDS, conductivity, alkalinity and hardness. This type of water composition is particularly problematic for traditional Cr(VI) treatment systems based on ion exchange or reduction/coagulation/filtration (RCF) Cr(VI) remediation.
The operation of the stannous generator system is based on a proprietary approach that generates on demand a stannous ion reagent in-situ via an electrolytic process. Generating a stannous reagent onsite is a far more cost-effective treatment solution compared to traditional alternatives because tin and electricity are the only consumables with this novel approach. Additionally, the freshly generated stannous reagent poses no environmental and health risks unlike traditional tin reagents, such as unstable stannous chloride (SnCl2) solution, which is an acidic material requiring specialized handling.
The stannous generator system features automatic dosing and incorporates proprietary continuous, real-time monitoring of contaminant levels at the influent and effluent to ensure optimal treatment and compliance with regulatory and operational targets 24/7/365. Because the system can be fully controlled, monitored and optimized remotely, the presence of personnel on site for supervision is not required, further reducing operating costs compared with traditional treatment systems.
The pilot demonstrated the capability of novel technology to address Cr (VI) remediation down to non-detect levels by converting toxic Cr (VI) to insoluble nontoxic Cr (III), which then can be removed by filtration along with tin dioxide — the product of the conversion. The technology was operated remotely and through its onboard online analyzer the system’s ability to effectively reduce Cr(VI) was seen immediately. Results
3:20pm IWC 21-51: Ammonia Nitrogen Conversion in Struvite Using a Novel Sustainable Electrocoagulation Process
Eric Bergeron, Golder Associates, Sherbrooke, QC, Canada
Treatment of ammonia nitrogen in groundwater, surface water, domestic and industrial wastewaters for various clients in the oil and gas, mining, food, slaughtering house and waste management (including landfill)) industries is challenging with conventional treatment technologies due to several limitation factors. Such factors, when biological treatment systems are used, include the presence of toxic contaminants in the water that can affect the performance of the ammonia and nitrite oxidizing bacteria or the limited footprint available on site. Other challenges can be associated with the high operating cost in chemicals and energy of physico-chemical treatment technologies such as air stripping or chemical oxidation processes. Golder has used a novel process to remove ammonia nitrogen based on the struvite (an agricultural fertilizer) formation using electrocoagulation to release in situ magnesium in order to combine with orthophosphate in water. The process developed is an alternative to conventional ammonia nitrogen removal technologies. The technology has the potential of reclaiming ammonia from water to make fertilizer. The EC technology using magnesium electrodes is a sustainable technology. EO uses one of the cleanest and safest reagents: “the electron.” The theory, two case studies and estimated operating and capital cost of this novel process will be presented. The struvite formation process will be discussed as well as observed theory deviations in practice. The first case study is a retrofit of this novel process to an existing mine water treatment for a water having an average of 35 mg/L of ammonia nitrogen to be reduced to less than 10 mg/L and a maximum flowrate of 400 m3/d. The second case study is a landfill impacted groundwater treatment (pump and treat system) incorporating the novel process as the upstream treatment unit for a maximum flowrate of 166 m3/d in order to reduce the ammonia nitrogen from an average of 5 mg/L to less than 0.49 mg/L. The process also removed other contaminants: metals, hydrogen sulfide, suspended matter (colloidal form), mineral oil and grease, phosphor and surfactants.
4:10pm IWC 21-52: Sustainable Cooling Water Systems – Opportunities and Novel Solutions
Walt Kozlowski, Evoqua Water Technologies, Schaumburg, IL; Jon McClean, Evoqua Water Technologies, Pittsburgh, PA; Ben Sparrow, Saltworks Technologies, Richmond, BC, Canada
Open-evaporative cooling water systems present multiple opportunities to improve a site’s sustainability position by reducing water, energy, waste, and chemical use. Sustainability of a cooling system can be impacted by proper selection and application of equipment and chemistry; however, this paper will focus on equipment with the following objectives:
- Identify areas where water treatment equipment can have the most impact on sustainability
- Discuss innovative solutions to common challenges
- Present a case study supporting an example of a novel solution
Traditional methods of cooling tower water treatment usually involve feed of scale and corrosion inhibitors and limiting cycles of concentration based on LSI calculations. Biological growth is often controlled with biocides such as bleach or bromine. However, cycles of concentration are limited when using chemical programs alone, bleach feed can cause increased system corrosion, and cooling efficiency can be reduced by fouling from suspended solids. These conditions can have a negative impact on sustainability.
Water treatment equipment can positively impact sustainability in cooling systems in multiple areas. The most common areas are:
- Makeup or sidestream filtration to remove suspended solids and reduce fouling
- Non-chemical methods to control biological growth
- Removal of scaling ions to increase cycles
Data centers usually have extremely high heat loading, maintaining a clean system is critical for operations and to minimize energy use. Maintaining effective and continuous cooling is critical. Recently, a large organization which operates multiple data centers across North America had a goal of maximizing heat exchanger efficiency by limiting fouling combined with reducing chemical feed and waste. The solution was to utilize a high-efficiency sand filter for particulate removal in combination with UV for biological control. This combination has proven to minimize particulate loading while significantly reducing the need for biocide feed by over 75%.
In many cooling systems, calcium and/or silica are scaling species that limit cycles of concentration. Scale-control chemistries have limitations and operators are sensitive to increasing cycles by increased chemical feed as this can be challenging to control and is often cost prohibitive. Electrodialysis reversal (EDR) provides the ability to increase cooling tower cycles and reduce water use by selective removal of these ions. EDR is a proven technology that acts as a kidney loop when installed in cooling systems. This paper will review the pros and cons of EDR and where it is the best fit to support water reduction goals.
Tuesday, 11/9/2021; 1:15 PM
T7-RO & Membranes #2
IWC Rep: Dennis McBride, Burns and McDonnell, Kansas City, MO
Session Chair: Tom Imbornone, Avista Technologies, Inc., San Marcos, CA
Discussion Leader: Tony Fuhrman, LG Chem, Torrence, CA
Membrane systems are becoming increasingly prevalent across the globe due to their reliability, performance, and efficiency. All membrane systems have waste streams that must be addressed. Many RO systems are also prone to bio-fouling. This session discusses alternative approaches to cope with bio-fouling of RO membranes, a revisit of cellulose acetate membranes, and an approach to purifying complex waste streams from membrane plants.
1:25pm IWC 21-53: Be Free of Biofouling in your RO System
Marc Slagt, DuPont Water Solutions, Zealan Netherlands; Guillem Gilabert Oriol, DuPont Water Solutions, Tarragona South, Tarragona, Spain; Denise Haukkala, DuPont Water Solutions; Donna Murphy, DuPont Water Solutions, Spring House, PA
Biofouling is identified as one of the most common and severe operational issues plant operators face in today’s RO operation. The detrimental effects of biofouling in RO systems can decrease water supply reliability significantly while at the same time increase the total cost of water by additional energy, chemical consumption and reduced membrane lifetime. This presentation will discuss a novel vessel-based multimedia technology that effectively and efficiently mitigates the negative effects of biofouling in downstream RO systems by its ability to instantly create and sustain reliably a biostatic environment. Data will be presented that demonstrates over 1.5 years of zero biofouling and trouble-free RO operation in an industrial scale pilot trial conducted in a desalination plant in Spain suffering from the negative effects of biofouling. This novel treatment system has the potential to significantly improve the stability of plant operations and reduction of plant downtime thanks to the reductions in CIP frequency up to 75% and in membrane replacement rates.
2:15pm IWC 21-54: Cellulose Acetate Membrane is Not Dead
Nik Mehta, MICRODYN-NADIR, Goleta, CA; Elke Peirtsegaele, MANN+HUMMEL Water & Fluid Solutions, Goleta, CA
For many years now, spiral-wound reverse osmosis (RO) and nanofiltration (NF) elements have proven very successful in alleviating freshwater shortages by treating various waters and wastewaters. In fact, spiral-wound RO and NF membrane elements are the most used desalination technology available on the market. Although RO and NF membranes are a relatively new technology, there have been many developments and changes in the membrane materials that have paved the way to the increasingly robust technology in use today. Today, RO and NF membranes are commercially available in either cellulose acetate (CA) or polyamide membrane chemistries. While newer thin-film polyamide chemistry largely dominates the current reverse osmosis membrane market, there are still applications where CA membrane is favored due to its specific properties and performance.
This paper dives into the history behind how CA membranes were developed, improvements made to the membrane chemistry over time, and how its chemistry differs from polyamide-based membranes. It also discusses the benefits that CA membranes offer, including the fact that these membranes can handle residual chlorine and why they are less susceptible to fouling. Lastly, this paper looks at the different applications and case studies that CA membranes are used in and why they are preferred over polyamide-based membranes, proving that CA membranes are here to stay.
3:20pm IWC 21-55: Enzymatic Cleaning Restores the Performance of Biofouled Membranes at Mild Conditions
Xingpeng Zhang, Suez Water Technologies & Solutions Singapore Pte Ltd, Singapore; Jeffrey Melzer and Nicholas Popolizio, SUEZ Water Technologies & Solutions, Trevose, PA; Agata Zarebska, Novozymes, Denmark; Henrik Bangsø Nielsen, Novozymes, Denmark
Reverse osmosis, nanofiltration, and ultra-filtration membranes are used to purify different sources of water including surface, sea, and mine waters for potable applications, irrigation, industrial water production, and to reduce fresh water demand via reuse of wastewater to address the increasing demand for clean water around the world. However, membrane fouling is a critical factor impacting reverse osmosis operations. In a majority of membrane autopsies conducted by SUEZ, biofouling is the major foulant that causes membrane failure. Organic debris including Extracellular polymer substances (EPS) can build a layer on membrane surfaces and brine spacers. Organic material build up can increase the hydraulic resistance to the free flow of water across the membrane, reducing permeate flow and causing a negative impact reducing productivity, decreasing permeate quality, and increasing energy consumption.
Efficient cleaning of biofouled RO membranes often requires harsh chemicals, including biocides and/or strong alkaline cleaners, that can damage the membrane. In contrast, enzymes can be powerful targeted catalysts to break down organic macromolecules into smaller molecules during normal clean in place (CIP) operations. While enzymes have been used in the Food & Beverage industry for daily maintenance (cleaning process membranes to remove proteins, grease, fat, and sugars), they have not been used extensively during water systems CIP operations due to the nature of the biofouling and operating conditions in these applications.
SUEZ – Water Technologies & Solutions and Novozymes investigated the nature of biofoulings on membranes and enzymes/chemical combinations that could address breaking through the polymeric layer for water filtration systems. We discovered that a proprietary combination of enzymes and cleaner formulations can effectively clean biofouled membranes. Consequently, CIP’s can be conducted with milder pH and reduced chemical usage.
This paper covers the discovery from laboratory, to piloting, to field application, demonstrating the efficiency of enzyme-enhanced cleaners compared with harsh alkaline cleanings in restoring the performance of biofouled membranes.
4:10pm IWC 21-56: Converting Highly Complex Municipal UF/RO Reject Waste Water to OTSG Boiler Feed Water in the Middle East
Prasad Kaniampal, Aquatech, Canonsburg, PA; M. N. RAO, Aquatech, Canonsburg, PA
In recent years, a prestigious Oil Company in the Middle East has intensified its efforts to extract heavy oil for which water is a critical component for steam generation. Deviating from the conventional way of treating ground water or sea water to produce Once-Through Steam Generator (OTSG) Boiler feed water, the Oil Company decided to investigate using the Ultrafiltration (UF) / Reverse Osmosis (RO) Reject Waste Water from nearby Municipal Waste Water Treatment Plant. They were looking for an environmentally sound and economically viable solution to achieve their ‘best out of waste’ sustainability goal.
The major challenge was the waste water itself, due to it being a highly complex waste water with high levels of Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Hardness and Total Dissolved Solids (TDS). The original Front End Engineering Design (FEED) process scheme intended for treating this waste water was found unreliable in meeting required OTSG Boiler feed water production and quality.
Aquatech developed a solution-oriented alternate scheme, which not only guaranteed required OTSG Boiler feed water production and quality but also resulted in significant capital and operating cost savings. The alternate scheme consisted of similar unit processes as in the original scheme but in a different configuration.
This paper discusses the benefits of alternate scheme over the original FEED scheme thereby providing insight into developing a solution-oriented approach for Oil & Gas customers.
Tuesday, 11/9/2021; 1:15 PM
T8-Proven Strategies for Water Reuse
IWC Rep: Ivan Morales, Integrated Sustainability, Inc., Houston, TX
Session Chair: Mike Preston, P.E., Kiewit, Lenexa, KS
Discussion Leader: Alan Daza, Safbon, Tampa, FL
Water recycle and reuse continue to be the foundational principles for good water management and sustainability practices. The goal is to reduce industrial impact to local water resources and improve the quality of life in local communities. These admirable goals are often met with the hard reality and challenges that are exposed in actual practice. Our four papers discuss successes and challenges that were encountered in different reuse and recycle scenarios across varied industries from high purity water to produced water recovery.
1:25pm IWC 21-57: Swirltex: A Novel Spin on Membrane Treatment for Oily Wastewater
Melanie McClare, P.E., and Peter Christou, Swirltex, Calgary, AB, Canada
Swirltex uses ultrafiltration tubular membranes in a unique manner to remove suspended solids, oil and bacteria from wastewater. The novelty of the innovation is centered around the injection of microbubbles of gas and induction of a spiral flow pattern within the tubular membranes. This effect results in an increase in production rates through the membranes while reducing fouling rates at the membrane surface, a common shortfall of membranes.
This technology therefore unlocks the opportunity to employ the benefits of membranes in wastewater chemistries where they were previously uneconomical. Swirltex has tested its technology on industrial wastewater containing high levels of solids and oil. In this presentation, Swirltex will provide various case studies including airport glycol stormwater, produced and flowback water, and dairy wastewater to show the flux and energy performance of the Swirltex system as compared to conventional tubular membrane systems. Lessons learned and pre-treatment recommendations for each type of wastewater will also be presented.
2:15pm IWC 21-58: Implementation of Ultrafiltration and Reverse Osmosis to Increase Demineralization Capacity at Consolidated Edison East River Steam Generation Facility, New York
Brandon Coombs, Wigen Water Technologies, Chaska, MN; William Sellerberg, Consolidated Edison Company, New York, NY; Michael Bourke, Wigen Water Technologies, Centennial, CO
Consolidated Edison Company of New York (Con Edison) has five steam generating plants in New York City that provide steam for heating residential and commercial buildings. The water used to generate the steam requires demineralization treatment to prevent scaling in the boilers and the steam distribution network.
Con Edison’s East River steam generating facility is located alongside the East River on the Lower East Side of New York City. This facility has two existing systems to treat boiler feed water, one is a mixed bed cation and anion demineralization system and the other utilizes Reverse Osmosis and Electrodeionization. The original mixed bed demin system was designed to handle low conductivity feed water from the Delaware/Catskill Reservoir System but in recent times the city was providing Con Edison with higher conductivity water from the Croton Reservoir system, resulting in decreased demin capacity and frequent regeneration of the mixed bed demineralizers. The initial solution was to use rental Ultrafiltration (UF) and RO systems to make up the extra capacity. Due to limited space in Manhattan, and high costs for rental equipment, Con Edison decided to install a permanent UF and RO system to replace the rental trailers.
The selected location for the UF and RO equipment was on the ground level of the East River facility. The project was to provide 8 MGD of RO permeate capacity with UF pretreatment that could fit within the very constrained basement floor area. Wigen Water Technologies was selected to provide this equipment. Key to fitting all of the equipment in the available space was an innovative stacked RO train configuration, where two sets of 2 MGD RO trains were stacked on top of each other to provide 8 MGD capacity in a footprint where less than 4 MGD capacity would normally be possible. The ultrafiltration trains were also designed to minimize footprint. Design of this equipment required precise 3D modelling to ensure it would fit within very tight tolerances when delivered to site.
The new UF and RO systems have provided reliable operations through two full winters and Con Edison operations and the quality of water delivered to the demin system is consistently well below the target of 50 µS.
This presentation will discuss how the project was implemented and provide data on improvements to the demin system feed water quality with UF and RO pretreatment and the impact on the subsequent regeneration frequency.
3:20pm IWC 21-59: Non-phosphorous Corrosion Inhibition in High Total Dissolved Solids Reuse Water
Mary Jane Felipe, Ph.D., and William Mansfield, Baker Hughes, Sugar Land, TX; Greg Davis, Bartholomew Ramplin, and Jeffrey Miller, Baker Hughes, Huntington Beach, CA
Water reclamation and reuse offer an effective means of conserving freshwater supplies. Along with the continued global warming and increase in pricing, the use of fresh water as a makeup water for cooling towers is becoming more cost prohibitive. To alleviate, refinery operators are implementing the use of reuse water.
It is known that reuse water contains a high amount of total dissolved solids. As the water’s dissolved solids level increases, corrosion and deposition tendencies also increase. When the water conductivity increases, treating mild steel corrosion becomes more difficult and the traditional chemical solutions becomes limited. This paper details the effective corrosion inhibition of up to 8000 micromhos allowing water cycling of reuse makeup water from 2-3 to 5-6 cycles of concentration. Very low corrosion rates (<0.5 mpy) were achieved with no discernible etching, pitting, or other corrosion mechanism observed. The non-phosphorous corrosion inhibition solution also mitigated the formation of calcium phosphate scale.
4:10pm IWC 21-60: Industrial Wastewater Reclamation Case Histories and Lessons Learned
Daniel Sampson and Cristina Piekarz, HDR, Walnut Creek, CA
On-site reclamation of high of low TDS waste streams is a common feature of most modern industrial facilities. The design of these facilities generally assumes plant operation under steady-state conditions at various levels of production. Most designers do not, unfortunately, anticipate the impact of non-steady-state or off-design operation, the impact these operating periods might have on the plant’s water systems, or the impact likely contaminants may have on reclamation systems.
Industrial wastewater reclamation systems typically include provisions for removal and/or sequestration of suspended and dissolved solids, but may assume that these contaminants enter the plant only via the normal makeup water supply and that, once removed, these contaminants do not re-enter the system. Other sources of suspended and dissolved solids may include normal chemical feed, corrosion products from plant piping, dust and debris from the surrounding environment, and washdown water.
In addition to suspended and dissolved solids, temperature and organic contamination have created problems at several facilities. On-site reclamation equipment seldom includes treatment steps to address these issues.
This paper examines the on-site industrial wastewater reclamation systems at several industrial facilities including the original system design and intent, what was missed, what problems the plants experienced, and what the plants did to address these problems. Common problems observed included:
- Temperature control in service and wastewater reclamation tanks
- High suspended solids loading and increased fouling of membrane systems, valves, and other equipment
- High purity water treatment concerns and chemistry impacts
- Contamination of high purity steam systems
- Increased corrosion and corrosion product transport
- Specific contaminant recirculation and concentration
These problems demonstrate the impact of unintended consequences. Industrial wastewater recovery may seem relatively straightforward, but this paper will demonstrate that attention to detail is critical. Real-world experience clearly shows that non-steady-state and off-design operation, far from being infrequent and negligible, actually create the most significant issues with regard to reclamation systems and the facility water balance. The paper contains observations, recommendations, and lessons learned that may be of use to others with similar systems.
Wednesday, 11/10/2021; 8:00 AM
W1- Power & FGD (Water Chemistry to Power Success)
IWC Rep: Derek Henderson, Duke Energy Corporation, Raleigh, NC
Session Chair: Jason Monnell, Electric Power Research Institute (EPRI), Charlotte, NC
Discussion Leader: Dave Guinta, Burns & McDonnell, Kansas City, MO
In this session, we will splash into process design, chemical treatment, and their operational impact to the treatment and management of high-volume water streams in the electric power industry. We will explore biofouling control for cooling water systems, wet FGD Scrubbers additives, and innovative FGD wastewater treatment designs. It will be sure to provide engaging discussions, idea generation, and in-depth details regarding these solutions.
8:10am IWC 21-61: Halogen Stable Azole: Effectiveness and Mechanism of Action in Cooling Water
Mary Jane Felipe, Chelsea Eaton, Swamy Margan, and Steven Lee, and William Watson, Baker Hughes, Sugar Land, TX
Copper alloys are used in cooling systems because of their excellent heat transfer properties. In the advent of copper alloy corrosion though, releasing the copper ions to the water not only raises an ecotoxicity concern in the effluent discharge but also induces galvanic corrosion to mild steel metallurgies leading to a bigger corrosion problem in the cooling systems. The use of triazole has been the go to chemistry since the 1970’s. Triazoles such as tolyltriazole and benzotriazole are known to effectively form a film on copper metallurgies. The presence of nitrogen and the ring structure enhance film formation at the solid-liquid interface.
In a cooling water system, one of the basic problems to combat is the possible growth of microorganisms. These microorganisms can induce a type of corrosion that is often harder to treat than general corrosion. To mitigate, it is typical to feed halogen-containing biocides like chlorine and bromine. These oxidizing biocides are maintained at a fairly low parts per million level, however, it is very common to feed higher biocide level when the pump is not maintained properly. During biocide upsets, corrosion rates of the copper alloy metallurgies also increases because of the tolyltriazole’s interaction with the halogen containing biocide.
This paper presents a halogen stable azole that forms a film on copper alloy metallurgies even in the advent of halogen-containing biocide upsets in cooling water systems. Corrosion inhibition is investigated using linear polarization resistance monitoring. Further mechanistic studies was done using Tafel polarization and impedance studies. Field data confirmed a 50-85% reaction of chlorine-containing biocide when a typical tolyltriazole inhibitor is used to prevent copper metallurgy corrosion. This data corroborates the data shown in the laboratory.
9:00am IWC 21-62: Design Innovations for the Largest FGD Plant in North America
Evan Claytor and Precious Ukonu, SUEZ Water Technologies & Solutions, Glen Allen, VA; Charles Chappell, TVA, Knoxville, TN; Mark Owens, HDR, Mosely, VA
Tennessee Valley Authority (TVA) and SUEZ were faced with the challenging engineering task of designing the largest FGD wastewater treatment plant to date in North America with a flow capacity of 4,400 gpm. In addition, the plant had a requirement for complete system redundancy. Several engineering design innovations occurred which allowed the project to maintain the budget, schedule, and the required operational flexibility. These design innovations are as follows:
- The dual reactor tanks associated with each clarifier.
- A very high rate synthetic media gravity filter
- The elimination of acid feed prior to filtration
- Duplex stainless steel was chosen as the material of construction for the tanks as a less expensive alternative to typical FGD coatings.
This paper will discuss how the wastewater treatment system was developed and designed to meet TVA’s needs. The dual reactors allow for system turndown to 25% of the design flow without sedimentation in unwanted parts of the clarifier due to low velocities. This design eliminated the need to stop and start the clarifier frequently. The very high rate media filter allowed the system to achieve the required effluent concentrations while reducing the footprint of the filtration equipment by roughly 90%. By using a synthetic media which is not prone to scaling by calcium carbonate and calcium sulfate, this design eliminated the need for hydrochloric acid feed. This is typically required in for sand media applications treating FGD wastewater. Lastly, we will present the startup and initial operational data to demonstrate that the design changes not only have theoretical benefits but also perform in the real world by meeting the effluent requirements.
10:20am IWC 21-63: Effects of WFGD Additives such as DBA on Wastewater Treatment
Suzette Puski, Stantec, Providence, RI; Bill Kennedy, Stantec, Charlotte, NC
Many Wet Flue Gas Desulfurization (WFGD) systems use additives regularly to meet emission limits that were enacted after the scrubber system was designed, when firing higher-sulfur/lower-cost fuels, or when there is a system upset such as a loss of a recirculation pump or scaling/buildup inside the reactor. These additives maximize the operating flexibility of the WFGD system and reduce capital expenditure.
Organic acids such as DBA can provide additional benefits beyond the WFGD system by decreasing the load on the bioreactor in wastewater treatment and improving selenium removal.
It is also important to understand the flexibility of the wastewater treatment system to handle variability in WFGD effluent discharge with reduced load and on/off operation when balancing against renewable energy sources. Decoupling wastewater discharge from WFGD dewatering operations provides benefits of a maintaining a steady, concentrated flow to the treatment system.
This presentation will describe the different additives commonly used in WFGD systems, the benefits the additives provide, and how to monitor scrubber performance to reduce wastewater discharge. It will also review the impact of additives and WFGD operation on different Wastewater Treatment systems in terms of design and performance.
11:10am IWC 21-64: Enrichments of Anaerobic Selenium Oxyanion Reducers from FDG Wastewater
Preom Sarkar, Meghan Brandi, Nicholas Means, and Djuna Gulliver, NETL-DOE, Pittsburgh, PA
While flue gas desulfurization systems are an important technology in mitigating air pollutants, such as sulfur oxide gases, from coal fired power plants, much of the wastewater produced when using this technology contains other pollutants that must be remediated before release back into the environment. Selenium is one of these pollutants of interest because it can cause detrimental ecological consequences even in small amounts. Currently it is known that biological treatment can be utilized to treat FGD wastewater in order to remove selenium, but the microorganisms involved in this process in this relatively extreme environment has not been studied. This project seeks to enrich, identify, and characterize the anaerobic microorganisms in FGD systems that have the capability to reduce selenium oxyanions (selenate and selenite) to elemental selenium and characterize the selenium nanospheres they produce. Presently, we have found a microbial community within the FGD effluent capable of reducing up to 99% dissolved selenate. The community was found to be composed primarily of bacteria from the genera anaerosolibacter and bacillus. This work begins to characterize a little understood microbial system, giving operators an opportunity to optimize FGD effluent treatment technologies.
Wednesday, 11/10/2021; 8:00 AM
W2-Water’s New Flex
IWC Rep: Max Brefeld, TOYOTA MOTOR NORTH AMERICA, Georgetown, KY
Session Chair: John Van Gehuchten, McKim & Creed, Sewickley, PA
Discussion Leader: HG Sanjay, Bechtel, Reston, VA
The water world has been busy over the last year. Technology in the industry keeps improving and, in this session, we will take a look at a few of those innovations. In this catch all session there are new instruments, more uses found for brewery wastes, old water plants finding a new life, and investigating new nonfilter materials. Everyone can find something to like with this talented group of authors.
8:10am IWC 21-65: The Value and Challenges of Chlorination/Dechlorination Process Optimization in
Vadim Malkov, Ph.D., Hach, Loveland, CO; Mark Flynn, Heorot Power Management, Vernon, CA
Monitoring the quality of water used for power generation, even before the steam cycle, is extremely important, especially if the source water is reclaimed. Such water must undergo rigorous treatment involving multiple filtration steps, including reverse osmosis (RO), as well as chemical treatment. Besides anti-scalant addition and pH adjustment, chemical treatment usually involves disinfection to control biocontamination, followed by dechlorination to preserve RO membrane integrity. Maintaining the delicate balance between having enough chlorine in the water to control membrane fouling, but not too much to prevent it from destroying the polymer fibers, is an ongoing and difficult task for utilities. To control chlorine residual, utilities use available methods and instrumentation, which may not be able to provide adequate results because of infrequent, indirect, or inaccurate measurement.
A Heorot Power generation station monitors chlorine after the microfiltration phase with a process analyzer, which controls sodium bisulfite (SBS) feed. Personnel rely on grab sample analysis for monitoring chlorine residual after SBS addition in the first-pass RO feed. Arranged in four alternating vessels, the RO membranes are routinely cleaned in a clean-in-place (CIP) process, the frequency of which varies based on season and the consistency of chlorine presence in the water. The utility targets 0.02–0.08 ppm chlorine residual in this phase of water preparation, but it is challenging to achieve this goal while minimizing CIP frequency. As a result, chlorine excess in the RO feed sometimes leads to unscheduled and costly membrane replacements. Losses comprise the direct cost of the membranes themselves as well as the indirect cost of lost energy production. In search of a better way to maintain their assets, the utility decided to try a new analyzer directly measuring ultra-low chlorine concentrations in the RO feed and automatically reporting the results every 150 seconds.
The trial lasted several months, and the analyzer was exposed to challenging conditions. Once the operators realized the benefits of automatic chlorine measurements vs. grab sample analysis, they connected the analyzer to the distributed control system (DCS) and used it to advise SBS feed control. Improved management of the chlorination/dechlorination process resulted in a more than 30% reduction in SBS usage and halved the frequency of CIP. This process optimization is also projected to reduce losses in power production and increase the useful life of RO membranes, which will provide further cost savings for the utility.
9:00am IWC 21-66: Using Brewery Waste to Optimize Nitrogen Removal in a Biological Nutrient Removal
Coralynn Revis, HDR Engineering, Missoula, MT; William Buxton, HDR Engineering; Tom Radcliffe, City of Bozeman, Bozeman, Montana; Theodore Grover, HDR Engineering; Josh French
This presentation will discuss the results from a nutrient removal augmentation process that was piloted by HDR Engineering and the City of Bozeman Water Reclamation Facility (WRF). The pilot involved dosing brewery waste in the WRF bioreactors to improve nitrogen removal. The results of this brewery waste pilot project will be pertinent to nutrient standard compliance efforts across the country, and offer wide applicability in their potential to be replicated elsewhere.
Communities throughout the United States are facing increasingly stringent nitrogen effluent limits, leading many to invest in costly nitrogen removal infrastructure upgrades at their treatment facilities. One of the limiting factors within a nitrogen removal process is the availability of carbon. In these situations, communities must often inject alternative carbon sources such as MicroC or methanol. These products can be both expensive and hazardous to handle.
There has been a proliferation of new microbreweries in recent years, but breweries create high strength waste streams that must be disposed of in some fashion. Disposal of this waste can negatively impact the environment and significantly impact the economic and financial viability of the microbrewery industry. However, if used properly, this brewery waste offers an alternative carbon source that is both safe to handle and is relatively inexpensive.
The HDR pilot study involved using a vactor truck to collect and transport brewery waste to the WRF. During the pilot, brewery waste was dosed over a three-week period in a single bioreactor train for 12-hour periods. A nitrate probe was installed at the end of the train to measure any performance changes. During the dosing periods of the study, the test bioreactor was able to achieve total nitrogen concentrations of 0.5 – 2.0 mg/L lower than those achieved in the control bioreactor. This equates to a 25-40% reduction of the total nitrogen entering the discharge stream. The results of the study validated the theory that injecting brewery waste to the right stage of the wastewater treatment process would lower nitrogen levels.
10:20am IWC 21-67: Repurposing Existing Paper Mill Wastewater Treatment Plant For Future Flow
Mayra Giraldo, Stantec, Atlanta, GA; Nicole Stephens, Stantec, Raleigh, NC
Industrial wastewater treatment systems are designed to accommodate maximum flow and load conditions and a common design challenge is maximizing throughput in a limited footprint. It is rare, however, to encounter the question of how to adequately treat flows that are 25 times lower than the existing system’s treatment capacity. This paper will document treatment considerations and recommendations for a pulp and paper mill system following decommissioning of paper machines resulting in a significant flow reduction and shift in wastewater strength.
The original unit processes were designed to treat a maximum flow of 25 million gallons per day (MGD) and have since been modified several times to manage minor flow reductions. The anticipated decommissioning of paper machines will reduce the total wastewater flow to 1 MGD, which exceeds the turndown capacity of existing processes. This presents several operational challenges such as managing flow through aeration basins while maintaining an adequate food to mass ratio (F/M) and operation of filter presses for sludge dewatering. A material balance was developed to model existing and future plant conditions and validation of the future conditions via sampling. The addition of supplemental BOD was evaluated to sustain the secondary treatment against decommissioning of the system. Conversion of the existing primary clarifiers to a physical chemical (phys/chem) treatment system for metals removal was also considered. Additional alternatives considered include repurposing existing infrastructure to meet existing effluent discharge standards and continue discharging through the existing outfall and meet revised water quality standards for direct discharge into the public wastewater collection system.
11:10am IWC 21-68: Innovative Low Fouling, Chlorine Tolerant Hollow Fiber Nanofiltration Membranes for Micropollutant and Organic Removal
Erik Roesink, Robert Gerard, and Umang Yagnik, NX Filtration, Enschede, Netherlands
We see in our environment, specifically in our surface waters, more and more persistent chemicals like polyfluoroalkyl substances (PFAS), medical residues, insecticides, pesticides, nano-plastics, anti-biotic resistant bacteria, viruses; in general, micropollutants. This is caused by the fact that traditional wastewater treatment plants do not remove most micropollutants. Common technologies applied for removal of micropollutants include adsorption (activated carbon), advanced oxidation (O3, UV/H2O2) or multi-stage membrane processes, to re-use the effluent or to improve the effluent quality before disposal to surface water bodies. In this paper, an innovative solution for removing micropollutants using hollow fiber nanofiltration (NF) membranes, is presented.
These next-generation hollow fiber NF membranes are found to be suitable for direct treatment of surface water sources and (biologically treated) wastewater. These hollow fiber NF membranes remove color (via natural organic matter [NOM]), low molecular weight organics, micropollutants, and partial hardness, while allowing most monovalent salts to pass through the membrane. The membrane chemistry is based upon poly-ether-sulfone (PES), while the selective nanolayers are created from water-based electrolytes (layer-by-layer). The robust PES membrane in combination with layer-by-layer chemistry allows severe cleaning, e.g., with hypochlorite concentrations up to 200 ppm and a pH in the range of 1-14.
The main benefits of these innovative hollow fiber NF membranes include superior micropollutant and organics removal, fouling resistance, chlorine tolerance, minimal pretreatment, reduced chemical usage, and cleanability at a wide pH range. There is data to substantiate that these benefits translate to significantly low operating costs and lead to considerable CO2 footprint reduction.
The permeate from these hollow fiber NF membranes can be reused directly for a wide range of industrial process, agricultural applications. In combination with advanced oxidation as a post-treatment, the NF permeate can be used for more critical applications including drinking water.
Wednesday, 11/10/2021; 8:00 AM
IWC Rep: Bradley D. Wolf, P.E., Berkeley Research Group, LLC, Pittsburgh, PA
Session Chair: Russ Huffmyer, McKim & Creed, Sewickley, PA
Discussion Leader: Nicole Bolea, ECT2,
For this session on Perfluoridated Alkyl Substances (PFAS), the featured papers will cover the following topics; PFAS destruction by novel physical and chemical methods, solutions that have been implemented to address “low hanging fruit” and the sustainability of those solutions at a manufacturing site in North Carolina, a case study that will demonstrate the effective removal of high levels of PFAS compounds at a facility in Australia, and lastly, the development of a technology evaluation for PFAS treatment.
8:10am IWC 21-69: PFAS Destruction by novel physical and chemical methods
Hamid Amini and Brian Petty, P.E., Geosyntec Consultants, Huntington Beach, CA
Currently, aqueous PFAS treatment is primarily based on adsorption or ion exchange which does not destroy PFAS. Because PFAS compounds are extremely recalcitrant in the environment and bioaccumulate, transferring them from the aqueous phase to solid phase alone without destructive treatment does not solve the PFAS problem. PFAS destructive technologies are needed to avoid significant costs such as waste disposal for adsorptive media or brines.
Plasma technologies have been proven to degrade both PFCAs and PFSAs at ambient conditions without the need for addition of chemicals at relatively high energy efficiency and without known byproducts. Liquid film plasma is even more advantageous and has the potential to overtake them as the leading PFAS destruction technology. First, it utilizes a more advanced form of the plasma technology which is more scalable and improves the plasma-liquid contact and mass transfer that is required for efficient contaminant treatment. This will be translated to smaller reactor volume, lower equipment cost, and higher energy efficiency. Second, it also has a higher technology readiness level and existing commercial and manufacturing experience that will allow it to compete with the two better known plasma technologies and deliver a commercial PFAS solution to the market sooner. More detailed analysis of the advantages of liquid film plasma over the two other plasma processes and other destructive technologies will be provided. Bench-scale results for synthetic and site waters show promising results and will be described along with an economic analysis of the technology.
Another novel method in development involves sequential chemical additions, mixing, and manageable reaction times. The applications for this technology will be myriad given the relative simplicity, cost-effectiveness, and small footprint. Bench-scale results for synthetic and site waters show promising results and will be described along with an economic analysis of the technology.
9:00am IWC 21-70: PFAS Mitigation in Chemours – A Different Kind of Challenge
Steven Grise, The Chemours Company, Wilmington, DE
Traditional treatment technologies have been challenged to handle the unique nature of PFAS compounds in the environment. Many older technologies are ineffective due to the physical and chemical properties of the compounds.
The Chemours Company is committed to being a leader in environmental stewardship and responsible manufacturing, abating air and water emissions of fluorinated organic compounds by at least 99% at its manufacturing sites globally. Our Fayetteville Works manufacturing site in North Carolina has been at the forefront of that effort. We have focused on finding ways to get PFAS air and water emissions from our operations as low as possible, to both meet our commitments and address community concerns. While additional work remains to be done, we believe we have some of the answers to achieving our goals.
This paper will discuss some of the solutions we have implemented. These solutions include the “low hanging fruit” of water minimization, the more challenging aspects of water internalization and thermal oxidation, and the path ahead. The discussion will over the solutions and the sustainability of our decisions.
10:20am IWC 21-71: A Multi-Barrier Ion Exchange Process for the Removal of Short and Long Chain PFAS/PFOS Compounds
Rajeev Bhavaraju, LANXESS Pty Ltd., Granville, Australia; Dirk Steinhilber, LANXESS Deutschland GmbH, Koeln, Germany
Australia published “ The Intergovernmental Agreement on a National Framework for Responding to PFAS Contamination” in February 2018. This policy agreement provided for a consistent approach to PFAS contamination between the Commonwealth and the Australian States. Australia had recognized the risk of PFAS contamination early on, phasing out fire foams and other materials made with these compounds as far back as 2003. Consequently there are many installations already in place for the removal of these compounds.
This case study will demonstrate the effective removal of high levels of PFAS compounds in impounded waste water waters from the Fiskville County Fire Authority (CFA) Training College in regional Victoria , Australia. The college was closed in early 2015 due to the detection of contaminated water on the site and indications of regional health concerns. Remediation steps were put in place and it is considered the first time in Australia that high levels of PFAS compounds have been removed to the lowest limit of reporting for PFAS .
Multiple stages of water treatment for a 125,000 gallon per day system were required due to the presence of dissolved organics, metals and suspended solids, in addition to the PFAS contamination. Major challenges at this site/project were high levels of PFAS compounds with variable feed composition, that had to be removed to the lowest limit of reporting for PFAS for both short and long chain compounds. On top of this, treated water quality had to meet stringent EPA standards for continuous discharge.
Perfluorobutyrate (PFBA), one of the “short chain” versions of these “forever chemicals” was the most prevalent and was the basis of breakthrough criteria. Short chain PFAS compounds are considered more difficult to remove.
Removal of the PFAS compounds was largely achieved using a robust multi-barrier ion exchange process (IX) in combination with conventional pre-treatment technologies. The IX configuration included a regenerable industry standard macroporous weak base resin followed by a single use highly selective anion resin designed specifically for the removal of these compounds in a lead lag configuration.
This paper will illustrate the use of both regenerable IX technology and highly selective single use resins for the removal of PFAS chemicals to non-detectable and/or very low regulatory limits
11:10am IWC 21-72: Developing Technology Evaluation for PFAS Treatment
Kristen Jenkins, Beth Landale, and Ryan Thomas, GHD, Duluth, GA
Revitalizing Auto Communities Environmental Response (RACER) Trust manages the environmental remediation and facilitates redevelopment of the former General Motors (GM) Powertrain manufacturing facility site at Willow Run in Ypsilanti, Michigan. Currently the water generated from a groundwater collection system is sent to the local Publicly Owned Treatment Works (POTW). The groundwater contains per and polyfluoroalkyl substances (PFAS), and Perfluorooctane sulfonate (PFOS) in particular was present above the Michigan water quality standard. Conventional alternative treatment technologies for the detected PFAS were evaluated in order to develop a cost-effective treatment process, which included granular activated carbon (GAC) and ion exchange (IX). Results of bench testing and alternatives evaluation for these conventional technologies were presented in a 2019 IWC paper and presentation.
Both GAC and IX technologies result in a PFAS containing residual which may require regeneration, including PFAS destruction through incineration, or careful management in a landfill to prevent re-release to the environment. Therefore, since 2019, developing technologies have been evaluated with the objective of identifying a treatment alternative that results in destruction or complete mineralization of the PFAS. The paper will present the following developing technologies, including the results of bench and/or pilot testing completed during 2020:
- Cyclopure’s Dexsorb® adsorbent with PFAS destruction by ball milling
- Wet air oxidation
- Alkaline ozonation
For each of the technologies, the treatment technology and results of treatment will be presented, as well as any testing performed to determine whether PFAS has been mineralized or lost through physical transfer.
In addition, during 2020, a pilot was conducted to oxidize iron and settle the precipitated iron along with any other precipitated solids. The objective of this pilot was to collect a sufficient quantity of solids to perform PFAS analysis on the solids. Lab testing results were inconclusive regarding whether PFAS were adsorbing to solids. Therefore, the pilot was performed to determine the fate of PFAS. Adsorption of PFAS to solids may result in restrictions on locations/landfills accepting it for disposal and may increase the disposal cost.
Wednesday, 11/10/2021; 8:00 AM
IWC Rep: Bill Kennedy, Stantec, Charlotte, NC
Session Chair: Jeff Easton, WesTech Engineering, Salt Lake City, UT
Discussion Leader: Ramesh Kalluri, KALLURI GROUP, INC., Houston, TX
8:10am IWC 21-73: In Hot Water: Heat Balance Modeling in Two Industrial Waste Water Treatment
Shannon Brown and Eduardo Casanova, Bayer Crop Science, Saint Louis, MO; Karen Budgell, Golder Associates, Lakewood, CO; Elaina Mason, Bayer Crop Science, Muscatine, IA; Erin Milligan, Bayer Crop Science, Kansas City, MO
High temperatures in biological waste water treatment (WWT) systems can jeopardize treatment. Microbial breakdown of biochemical oxygen demand (BOD) is accomplished by enzyme catalysis. The predominant reactions occurring within this breakdown are exothermic. While they vary among species, each microbe and associated enzyme has optimal temperature ranges. When temperatures rise too far above this range, enzymatic reactions slow and eventually stop due to denaturing of the enzyme to the point where the active site no longer fits the substrate. Sometimes microbial death will also occur. Therefore, operating temperature range is an important parameter for control of activated sludge WWT processes. Engineering heat balances are performed across these systems to help quantify the heat generated and lost within the process and to identify options for bioreactor temperature control. Heat balances were conducted for two industrial WWT systems that successfully treat pesticide manufacturing effluent. These two WWT systems both operate using aerobic biotreatment, but one operates as a conventional activated sludge process and the other utilizes the UNOX biotreatment process. For these balances, analogous, simplified chemistries were used to represent the bulk chemical oxygen demand (COD) constituents and their reaction. Data regression of operational data was used to determine zero order kinetic terms that would suit the bulk chemistry. Combined with first principles, this information was used to create a semi-empirical process model for each system that predicts temperature performance. In this paper, the methodology for using homologous chemistries to approximate the biochemical breakdown of COD in aerobic WWT systems, and incorporation of this information to create system heat balance models is explained. Performance data from the two operating industrial WWT systems, with comparison of the relative heat contributions from sensible heat, solar radiation, conductive and convective heat transfer from the environment, work, and heat associated with chemical reaction are detailed. Application of this methodology will allow creation of similar models for other WWT systems.
9:00am IWC 21-74: Do’s and Dont’s of Leachate Management
Ron Ruocco, Stantec, Charlotte, NC; Philip Pedros, Stantec, Burlington, MA; Peter Daniels, Stantec, Golden Valley, MN; Mayra Giraldo, Stantec, Atlanta, GA
Since landfill leachate is classified as industrial wastewater under federal guidelines, appropriate collection and treatment need to be implemented either on or off site to prevent contamination of groundwater, pollution of nearby environments, and human health issues. Leachate management planning, particularly at treatment facilities that directly discharge to a POTW, may not get the attention needed to maintain necessary regulatory compliance. Failure to adequately develop leachate management plans may result in higher than expected operating costs and disruption to landfill operations. The implementation of TMDL regulations and proposed changes to surface water quality standards for metals will make it difficult for POTWs to continue to accept untreated leachate.
Consideration must be given to future changes in leachate quality and associated capital and O&M costs to predict changes in treatment system costs. Leachate should be analyzed for regulated and unregulated constituents that may impact the long-term performance of the system and upcoming regulatory requirements.
This presentation will include a summary of potential regulatory drivers that may require leachate treatment systems, examples of treatments systems used at landfills, and a discussion of operational challenges and costs associated with implementing leachate treatment systems. The presentation will also discuss the quality of leachate from landfills and landfill gas condensate.
Future treatment development should evaluate potential performance changes so that technological advances can be proactively considered before implementing either engineered or operational leachate controls.
10:20am IWC 21-75: Biofiltration Advances for Treatment of Trace 1,4-Dioxane Concentrations
Phoebe Zheng and Brian Petty, P.E., Geosyntec Consultants, Huntington Beach, CA
1,4-Dioxane is a synthetic chemical used in a variety of industries and produced as a byproduct or impurity in others. Several wastewater agencies in the US are beginning to restrict 1,4-dioxane in wastewater discharge. Advanced oxidation processes (AOPs) are the technology most frequently used for 1,4-dioxane treatment in wastewater, but AOP systems are complex and expensive to install and operate, and the other parameters (COD, color, TSS, etc.) typically found in wastewater often interfere with AOP treatment.
Biofiltration can potentially provide a simpler, affordable, yet effective alternative to AOPs. Biological granular activated carbon (BioGAC), a typical type of biofiltration, was successfully applied in the last decades to the treat MTBE, a water contaminant that has similar physical and chemical properties with 1,4-dioxane. Recent progress in research has demonstrated that 1,4-dioxane is biodegradable, but most progress has been made in cometabolic degradation, which requires the addition of an alkane gas as the carbon and energy source. This creates problems in chemical handling, cost, and demand for operator attention. Only a metabolic biological treatment process for 1,4-dioxane would significantly overcome these issues.
We will present our bench-scale biofiltration column tests using a mixed microbial culture enriched by us that is capable of metabolic degradation of 1,4-dioxane at low concentrations. Two biofiltration columns were operated concurrently at the influent 1,4-dioxane concentrations of 25 and 500 μg/L, respectively, as the sole carbon and energy source for the culture for over two years. Media tested included granular activated carbon (GAC) and a variety of common and proprietary adsorbents. The empty bed contact time (EBCT) was varied from 0.3 to 3 hours. For each set of operating conditions, influent and effluent 1,4-dioxane concentrations were monitored until the effluent concentration reached a steady state for at least four weeks.
Preliminary results showed that a significant percentage of 1,4-dioxane can be removed with biofiltration using GAC. The bioreactor performance was affected more significantly by EBCT than by the influent concentration. Types of adsorbent had a major impact on 1,4-dioxane removal. The maximum steady-state removal efficiency achieved during the bench testing was 99%.
11:10am IWC 21-76: Innovative Solutions in Water Treatment: Chemical Replacement – Managing pH with Carbon Dioxide in Place of Sulphuric Acid
Chris Milligan, P.E., and Tyler Elm, BlueInGreen, Fayetteville, AR
While the emergence of business sustainability as a corporate imperative and eﬀorts to improve energy, water, and material eﬃciency are relatively recent drivers of change in wastewater treatment, a long-standing – almost inherent – desire to mitigate the use of chemical treatments has existed for decades. Often expensive, sometimes hazardous, the use of chemicals in water treatment is widely considered to be a “necessary evil” of many treatment processes.
Chemical treatment methods – such as the use of sulphuric acid to control pH – can be extremely expensive treatments and their use is often associated with real and perceived risk to the health and safety of employees and the communities surrounding water treatment facilities. As such, water treatment professionals are generally open to opportunities that reduce or replace the use of strong acids and other chemicals. This desire to ﬁnd substitute treatment solutions became even more prevalent during the recent, global economic boom-and-bust cycle and its eﬀect on commodities.
Today, innovative solutions that address both the safety and the economic issues of using sulphuric acid for managing the pH of water are delivering a winning value proposition. The case studies presented herein highlight the value proposition of using CDOX® technology and CO2 to control the pH of wastewater in the power, mining, and food industries – replacing chemical treatments of sulphuric and other strong acids at a typically-sized implementation (180 lbs./hr.) and a very large-scale implementation (up to 2,400 lbs./hr.) with 100% redundant capacity on immediate reserve.