Conference Agenda

Session Overview
Location: 110AB
East Building
Date: Monday, 13/Sept/2021
10:30am - 12:00pmSession 05A: Stormwater
Location: 110AB
10:30am - 11:15am

Advanced Stormwater Treatment Innovation for Materials Recovery Facilities

Jennifer Schmitz

Clear Water Services, United States of America;

This presentation will highlight a case study on a waste and recycling facility located on the Lower Duwamish Waterway in Seattle, Washington. The case study will assess the stormwater challenges the Facility dealt with (run-on, runoff, discharge location variation, remaining in compliance with strict permit regulations) and discuss what steps the Facility did ahead of time in order to evaluate and select the appropriate long term stormwater treatment system.

The Lower Duwamish Waterway is known for legacy contamination due to decades of industrial activity and runoff from residential areas. The Waterway is an approximately 5-mile stretch of the Lower Duwamish River which flows into Elliott Bay and ultimately, the Puget Sound. In 2001, the US Environmental Protection Agency (EPA) added the Lower Duwamish Waterway site to the Superfund National Priorities List. Since then, The Department of Ecology (Washington State Permit Regulator) has led efforts to control sources of sediment pollution in the Waterway with cooperation from the City of Seattle, King County, and EPA.

In the Duwamish cleanup effort, total suspended solids (TSS) contamination was mandated by legislature as an effluent numeric limit. Recology CleanScapes, a recycling waste processing facility (Facility) and direct discharger to the Duwamish Waterway was having a difficult time remaining in compliance with TSS permit effluent limits while also struggling with total metals (zinc and copper) and other pollutants. Clear Water Services (Clear Water) was asked to assist in a design-build treatment selection process and develop a tiered approach for the Facility.

Clear Water was able to prove the efficiency of multiple treatment media and chemistries through bench scale testing and treatability. Using the results, Clear Water and Recology were able to select the best-fit treatment option for the Facility that was most practical for site constraints while also remaining cost effective and within their budget. Clear Water also provided the design and oversight of much needed infrastructure improvements in support of the treatment system selection: combining all site drainage to one discharge location, minimizing runoff from loading and unloading areas and run-on from neighboring properties.

11:15am - 12:00pm

Cold Climate Impacts on Green Stormwater Infrastructure

Kari Nichols

Mead & Hunt, United States of America;

Green Stormwater Infrastructure (GSI) is widely used throughout the largely temperate climate of the Pacific Northwest. However, not all areas of the region are as temperate, and as we are seeing more extreme weather events, we need to consider how GSI may react to more sustained exposure to cold, ice and snow, as well as heat and drought.

Studies around the world have been performed on the performance of GSI facilities in cold climates. Winter runoff conditions, including frozen ground, snow cover, and ice/snow melt events have the potential to adversely impact the performance of GSI, compounded by the addition of sand and chemical deicers to runoff pollutants of concern. In short, a colder climate can impact GSI in a variety of ways.

For instance, a cold climate may result in educed infiltration capacity for GSI. Although frost penetration does not necessarily equate to no permeability, ice lenses may still form, restricting infiltration. Additionally, rain and snowmelt events may reduce or eliminate frost depth in filter media present before and after events; however, larger snow melt events on frozen ground can result in increased runoff.

A colder climate can also reduce the effectiveness of treatment from vegetated systems as the biological function tends to “turn off” in the winter when the vegetation goes dormant. Cold climate regions may also have a shorter growing season, so plant establishment may be more challenging. The effectiveness of other treatments may be similarly reduced—for instance, there may be less sediment removal due to reduced settling velocities in colder water. All of these impacts must be considered in the design and selection of infiltrating best management practices.

Designers may need to include some additional considerations when selecting specific GSI solutions, such as potentially providing larger facilities in cold climates for snow storage and meltwater infiltration as long as road salt and deicing chemical usage is limited. However, the use of GSI still yields the most cost-effective benefits to stormwater runoff management, even in cold climates.

1:15pm - 2:45pmSession 05B: Stormwater
Location: 110AB
1:15pm - 2:00pm

Characterization and Application of Hydraulic Modeling to Assess Instream Enhancement

Adriana Piemonti, Anne MacDonald, Scott Mansell, Jadene Stensland, Amelia Yeager

Clean Water Services, United States of America;

Virtual Speakers

The Oregon Department of Environmental Quality (DEQ) implements the stormwater management programs under a permit officially known as “Phase I National Pollutant Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System (MS4) Discharge Permit”. Reducing or eliminating the impact of hydromodification on natural stream functions has become a stormwater permit condition for Oregon MS4 Phase 1 permittees. In general, permittees must promote infiltration of stormwater to alleviate hydromodification effects in nearby water bodies, such as increased water volume and increased water velocity in streams neighboring urbanized (or in development) areas. Some of the common detention facilities such as ponds, tanks and vaults are not suitable to achieve the proposed MS4 measured because there is not available space to allow their construction and development. For these scenarios, Clean Water Services (CWS) have considered the enhancement of stream corridors in lieu of detention facilities. This approach allows repairing degraded channels by reducing the velocity to which surface runoff reaches the main stream, allowing a reduction of the local and system-wide velocity, reducing erosion of channel beds and banks and allowing infiltration on designated flood plains. CWS have designed several project sites and designated them as informal field “laboratories” to test and evaluate the effectiveness of this approach. Stream corridor enhancement is made up of several components and instream features (such as large wood structures) is one of them. Commonly, the instream features require design analysis in urban streams to manage the potential for conflicts with existing infrastructure. Due to the complexity of these systems, modeling their effects on flow, velocity and stream depth is challenging. The proper characterization and simulation of instream features is very valuable, because we can estimate and quantify the interactions of a series of them, facilitating their design and the understanding of their field effectiveness. In this work, we present a series of three different techniques that support the simulation of the instream structures using a 2D model for one of our informal field laboratories. Our goal is to be able to demonstrate differences between the techniques and select that one that may represent better the instream structures.

2:00pm - 2:45pm

Rapid and Efficient Modeling of Citywide Urban Flooding for Extreme Storms

Nathan Foged

Brown and Caldwell, United States of America;

Virtual Speakers

As the magnitude and frequency of extreme storms increase, cities seek to understand the potential risks and possible impacts of a large and intense rainfall event. This type of extreme event produces runoff that far exceeds the design capacity of combined sewers and drainage systems, which generally results in multidirectional surface flows and flow paths are not readily apparent. Coupled 1-dimensional/2-dimensional modeling can simulate extreme flooding conditions in urban settings; however, the time and effort required to do so at a city scale is often impractical. This presentation will discuss a rapid and efficient approach to urban flood modeling implemented by Seattle Public Utilities (SPU) as part of the utility’s long-range planning to improve the resilience of local communities. The modeling approach reduces the problem to focus on surface flows and simplifies the 2-dimensional computations using the CADDIES tools developed by the University of Exeter. In addition, simulations were accelerated using parallel processing run through cloud computing resources. As a result of this work, SPU has prepared citywide flood risk area mapping and established a better understanding of the community’s vulnerable areas.

3:00pm - 5:15pmSession 05C: Regulatory Challenges
Location: 110AB
3:00pm - 3:45pm

PFAS in Biosolids Products - What To Do Next?

Todd Williams

Jacobs, United States of America;

Virtual Speakers

Per- and Poly- Fluoroalkyl Substances (PFAS) are a large family of organic compounds, including more than 5,000 artificial fluorinated organic chemicals used since the 1940s. They have been used extensively in surface coatings and protectant formulations for consumer products including paper and cardboard packaging products, carpets, leather products and clothing, construction materials, and non-stick coatings.

Recent studies have shown PFAS in WWTP influents to be in the tens to hundreds of nanograms per liter (ng/L). Conventional sewage treatment methods do not efficiently remove PFAS. Application of biosolids from WWTPs as a soil amendment can result in a transfer of PFAS to soil, which can then leach to groundwater or be available for uptake by plants and soil organisms and biomagnify to grazing livestock. PFAS have been detected in soils, groundwater, crops, and livestock near agricultural fields that receive PFAS-contaminated biosolids, fueling public concern.

As PFAS are recalcitrant and are not removed through conventional wastewater treatment, management of PFAS in biosolids is gaining increased concern and scrutiny.

This presentation will address the following questions related to PFAS in wastewater and biosolids:

  • What are PFAS?
  • Why are PFAS in wastewater?
  • What is the fate of PFAS in biological treatment systems?
  • What is the current status of regulations related to PFAS in biosolids
  • What technologies can be used to treat PFAS in biosolids?

Data will be presented on PFAS measured in biosolids before and after various biosolids treatment technologies including digestion, composting, drying, and pyrolysis. This presentation will help utility planners, operators, engineers and administrators understand the nature of the PFAS issue, how these compounds are introduced into wastewater and biosolids, the rapidly changing regulatory landscape, and what technologies are being used to eliminate these compounds from biosolids products.

3:45pm - 4:30pm

Water Quality Modeling and Monitoring to Support an Update of the Tualatin River Phosphorus TMDL

Raj Kapur, Scott Mansell, Leila Barker, Ken Williamson, Clint Cheney, Bob Baumgartner

Clean Water Services, United States of America;

Since 1988, the Tualatin River has had a total phosphorus TMDL which established stringent effluent limits. Clean Water Services has used a combination of biological processes and alum addition at the tertiary stage of the treatment process to meet phosphorus limits. Since 1988, the river has changed dramatically in terms of operations, flows, and water quality. Additionally, EPA has recently finalized a new aluminum standard in Oregon that will make it impractical to continue to use alum in the tertiary process for phosphorus removal. Clean Water Services conducted modeling that suggested that the Tualatin River was no longer sensitive to phosphorus inputs as it once was. Clean Water Services conducted a study in 2019 and 2020 where only biological processes were used for phosphorus removal with no tertiary alum addition and the effects on the Tualatin River were assessed. Results indicate that the treatment facilities can effectively reduce total phosphorus using biological processes without negatively impacting water quality in the river. Data gathered during the study will be used to update the water quality model and prepare a technical report to support an update of the Tualatin River phosphorus TMDL.

4:30pm - 5:15pm

Seeing the Whole Picture – Addressing Puget Sound Nitrogen Regulation Uncertainty as part of Biosolids Planning at Bellingham, WA

Anne Conklin1, Tadd Giesbrecht1, Susanna Leung1, Trung Le2, Rick Kelly2, Steve Krugel2, Rob Johnson3

1Carollo Engineers; 2Brown and Caldwell; 3City of Bellingham; ,

Virtual Speakers

The City of Bellingham (City) provides wastewater service for over 100,000 people at the Post Point facility. The City has been in planning efforts to replace their aging incinerators and implement a Class A biosolids and biogas strategy that aligns with their values and recovers the resources. The Washington State Department of Ecology (Ecology) has taken implementation steps to control nitrogen discharges from wastewater treatment plants to Puget Sound. Ecology recently issued a draft General Permit for public comment that identifies facility action level thresholds as a first step of potential future lower limits.

The City recognizes that nitrogen reduction will ultimately require significant costs and substantial treatment plant space, necessitating the need to plan for nitrogen removal Nestled at the edge of Bellingham Bay and surrounded by environmental critical areas, community amenities, and residential areas, Post Point is land constrained, requiring that “build out” conditions be evaluated to determine the ultimate capacity of the site.

The BC/Carollo project team evaluated the feasibility of two effluent scenarios and treatment strategies that would bookend the likely future range of nitrogen regulations:

  • Worst Case: 3 mg/L total inorganic nitrogen (TIN) year-round,
  • Moderate Case: 8 mg/L TIN summer only.

At least one treatment strategy was found for each scenario that could fit within the site constraints.


Date: Tuesday, 14/Sept/2021
8:00am - 9:30amSession 08A: Wastewater Process: Deammonification
Location: 110AB
8:00am - 8:45am

Zeolite-anammox Deammonification Of Biosolids Dewatering Recycle Stream: A Public Domain Technology

David Austin, Mark Madison

Jacobs, United States of America;

The Roseburg Urban Sanitary Authority (RUSA) operates an innovative deammonification wetland capable of treating 5,000 gallons per day, of biosolids filtrate that has an ammonia-N concentration averaging nearly 1,000 mg/L. Liquid from solids dewatering can go either to irrigation or deammonification. The purpose of the wetland is to remove ammonia-nitrogen during periods in the spring when irrigation is not feasible. It is the first commercial zeolite-anammox system.

Biosolids generated at RUSA’s WWTP are dewatered in a center screw press Monday-Friday, year-round. The filtrate from this screw press flows to an off-line clarifier and then is batch-loaded to two wetland cells by siphons. Wetland media is clinoptilolite (a zeolite). Beds drain by siphons to a recirculation basin where a pump transfers wetland effluent to the dosing siphons. Beds flood and drain excess water is pumped back to the plant’s aeration basins.

The wetland started in November 2016 and this presentation will focus on discussing the 4 years of operational experience as well as lessons learned. After a year of complete nitrification, the wetland converted to deammonification (anammox). Since then it has averaged 53 percent deammonification, significantly reduced the ammonia recycle load on the WWTP. Performance has been highly consistent in the past three years. Adding alkalinity to maintain pH above 7.0 while in the nitrification phase was crucial to establish deammonification. Once deammonification started, alkalinity demand stopped. However, recent analysis of performance indicates that maintaining a consistent operational pH of 7.5 to 8.0 – which is ideal - may require occasional alkalinity addition.

This technology is simple and non-proprietary and has potential broad application for small to medium size wastewater systems. Flood and drain contact beds were first used in the 1890s. Anammox was first observed in a contact bed in 1902. Recirculation in flood and drain beds is also public domain technology. With careful attention to design loading criteria, construction detail including the zeolite source, and alkalinity addition during the first nitrification phase; this technology is available to utilities to manage recycle streams with high levels of ammonia-N.

8:45am - 9:30am

Sidestream Deammonification MABR Development and Performance in Bench-Scale Reactor Treating Anaerobic Digester Dewatering Centrate

Bryce Figdore


A partial nitritation-anammox (deammonification) biofilm was grown in a bench-scale membrane-aerated biofilm reactor (MABR) treating dewatering centrate from a full-scale conventional mesophilic anaerobic digestion process. Anammox activity developed within 165 days of startup in absence of intentional seeding events or strategies such as seeding from an external enrichment or an integrated second-stage process treating partial nitritation effluent.

Average surficial NH3-N and TIN removal rates were 2.6 and 2.3 g N/m2-d for the 77-day operating period ending September 28, 2020 after anammox growth occurred and stabilized. In-situ anammox activity tests confirmed anammox activity and showed an average anaerobic TIN removal rate of 5.3 g N/m2-d under non-limiting substrate conditions, indicating that aerobic rather than anaerobic ammonia oxidation activity was rate-limiting under operational conditions.

These results suggest that MABR may be a viable deammonification alternative with reduced energy, seeding, and startup requirements compared to established commercial approaches.

Ongoing operations are further evaluating fundamental research questions, optimization strategies, and full-scale engineering implications.

10:30am - 12:00pmSession 08B: Wastewater Process
Location: 110AB
10:30am - 11:15am

Designing your Plant for Electrical System Reliability

Oskar Agustsson1, Jim Howard2

1HDR; 2LOTT Clean Water Alliance;

Virtual Speakers

A disruption to treatment plant operations can cause a cascading impact to a utilities’ operation as well as the potential for devastating impacts to the environment. However, as with any infrastructure, maintenance must be performed to ensure the long-term reliability of equipment. Electrical systems maintenance is a key aspect of maintaining the overall integrity of your system, but with it comes the risk of a potential disruption to the treatment process.

Maintenance is often not performed on treatment plant electrical systems because most systems do not allow for a partial shutdown of the electrical system without impacting the biological process and/or cutting off electricity to the entire plant. This ultimately leads to unreliable power and the risk of needing to repair or replace electrical equipment and systems at unpredictable intervals.

This presentation will focus on “safety by design;” how plant electrical systems can be designed to ensure maintenance without disruptions to the treatment process and how electrical system maintenance can be performed in a de-energized state. Case studies from LOTT Clean Water Alliance electrical improvements over the past decade will be used as examples in these concepts.

The presentation will cover a brief history of treatment plant electrical systems; how to perform electrical system assessments; which maintenance practices should be implemented on treatment plant electrical systems; and how and why to track your electrical system assets as part of an asset management program.

11:15am - 12:00pm

Advancing CSO Treatment – Piloting of OVIVO® RapidStorm™ Membrane Treatment

Bob Bucher1, Mike Snodgrass2, Marcos Lopez3, Scott Weirich4, Pardi Sukapanpotharam1, Pedro De Arteaga1, Ashwini Khare2, H.C. Liang3, Doug Berschauer4, Jessica Tanumihardja1

1King County Wastewater Treatment Division, Seattle, WA; 2Ovivo, Round Rock, TX; 3Tetra Tech, Inc., Seattle, WA; 4Parametrix, Seattle, WA;

Virtual Speakers

King County and project team identified a new technology for treating CSO discharges. The technology (RapidStorm manufactured by OVIVO®) uses silicon carbide (SiC) membranes in conjunction with the addition of a chemical coagulant. A pilot project was conducted at the County’s West Point treatment facility.

The RapidStorm pilot unit supplied for testing included SiC membranes plates arranged in three stacks installed in a 28-foot-long by 8-1/2-foot-wide by 17-foot-tall steel tank. Ancillary equipment included permeate / backwash pumps, coagulant feed system, a chemical cleaning system, air scour blowers, online instrumentation, and remote communication hardware. The pilot received feed flow from the West Point Treatment Plant primary effluent channel and supplemented with fire hydrant water, as testing required, to simulate lower strength CSO influent.

Process and performance testing objectives for the pilot study included documenting water quality performance and providing a basis of design for full-scale project planning. Water quality was monitored through online instrumentation, grab sampling, and composite sampling during multiple test runs. Process and performance testing was initiated in September 2020 with a total of sixteen test runs completed by the end of November 2020.

The pilot was successfully tested at an average instantaneous flux rate of 100 gallons per square foot per day (gfd), a peak instantaneous flux rate of 200 gfd, and under a simulated CSO hydrograph without exceeding the maximum transmembrane pressures of 10 pounds per square inch (psi). A flux rate of 100 gfd in the pilot was equivalent to approximately 300,000 gallons per day of treatment capacity.

Effluent water quality results were favorable with total suspended solids (TSS) less than 5 mg/l, turbidity less than 0.1 NTU, and fecal coliform count consistently less than 400 MPN / 100 ml without supplemental disinfection.

The development of new innovative technologies such as the one tested in this project have the potential to reduce the receiving water impacts from CSO, SSO and even stormwater discharges.

1:15pm - 2:45pmSession 15A: Wastewater Process: Nutrient Removal
Location: 110AB
1:15pm - 2:00pm

Planning for Nitrogen Removal in King County

Matt Winkler1, Rick Kelly1, Patricia Tam1, Eron Jacobson2, John Conway2

1Brown and Caldwell; 2King County WTD;

Virtual Speakers

The Washington State Department of Ecology (Ecology) has been evaluating the impact of nitrogen on dissolved oxygen concentrations in Puget Sound for over a decade. More recently, Ecology has taken steps towards implementing nitrogen limits on wastewater treatment plants (WWTP) that discharge into Puget Sound, and has begun to implement nitrogen load action levels on WWTPs as part of a nutrient general permit process that would trigger sequential tiers of nitrogen removal upgrades. King County operates three large, regional WWTPs (West Point, South Plant, and Brightwater) that discharge directly into Puget Sound. To better understand nitrogen removal options, costs, and other impacts, King County completed an evaluation of the potential for implementing various nitrogen removal options at these three WWTPs.

To evaluate nitrogen removal potential at the different facilities, pre-screening of over twenty different nitrogen removal, sidestream treatment, and intensification technologies was first completed, considering cost, nitrogen removal capabilities, greenhouse gas emission (GHG) potential, and other screening criteria. Then, pre-screened technologies were evaluated for various nitrogen removal scenarios for each facility, such as adding sidestream treatment only or meeting a range of seasonal or year-round effluent total inorganic nitrogen targets.

Potential conceptual site layouts and sizing for the alternatives for each scenario were developed based on modeling with calibrated process simulators. The results were used to identify a range of potential capital/operating costs, footprint requirements, and GHG emissions for each nitrogen removal scenario. In general, the results showed that capital/operating costs, GHG emissions, and footprint increase as the level of nitrogen removal increases, with some exceptions. The results also demonstrated that all three WWTPs have potential footprint limitations for nitrogen removal. This presentation will discuss the methods and results for the various effluent nitrogen removal scenarios for each of the three WWTPs.

2:00pm - 2:45pm

Construction, Commissioning and Start Up of the World’s First Advanced Biological Nutrient Recovery (ABNRTM) Facility at the Village of Roberts, WI

Jordan Lind

CLEARAS Water Recovery, United States of America;

Virtual Speakers

As wastewater treatment facilities face the challenge of selecting long-term and cost-effective solutions to meet more stringent discharge permit requirements, resource recovery has become a vital component for consideration. This presentation will highlight the construction, commissioning, and startup of the world’s first Advanced Biological Nutrient Recovery (ABNR™) by the Village of Roberts, WI to meet their ultra-low-level total phosphorus discharge limit of 0.04 mg/L.

Prior to integration of ABNR, the Village of Roberts utilized alum for chemical phosphorus removal to meet a discharge limit of 1.0 mg/L total phosphorus. To meet compliance, Roberts explored source minimization, facility optimization and performed a centrate evaluation, only to achieve 0.41 mg/L. Further exploration of facility modifications, led to piloting cerium chloride, ultra-filtration and ABNR. CLEARAS ABNR was the clear choice in consistently meeting future limits.

The Roberts ABNR facility is designed for 0.150 MGD and 4.0 mg/L TP. ABNR allowed the facility to leverage existing infrastructure and eliminate upstream chemical phosphorus removal resulting in cost savings. The flexibility of ABNR has also given Roberts the opportunity to plan for increased nutrient loadings from a future septage receiving program with a phased approach. See Figure 1.

Resource recovery has become critical to the wastewater industry and the CLEARAS process integrates the core principles of this concept. ABNR maximizes existing treatment infrastructure, extends the life of existing assets, allows for optimization of secondary treatment processes resulting in cost savings and residual algae-based sales. ABNR is a sustainable solution that enables wastewater treatment plants to transition to resource recovery facilities. In addition to the Roberts, WI project, ABNR has been pre-selected for three additional full-scale projects (two in WI and one in UT) which will be constructed in 2021 – 2022.

3:00pm - 4:30pmSession 15B: Wastewater Process
Location: 110AB
3:00pm - 3:45pm

Disrupting the Paradigm of Primary Treatment

Ann-Marie Doerhoff

Lakehaven Water and Sewer Authority, United States of America;

How do you change paradigms? In his book “The Structure of Scientific Revolutions” Thomas Kuhn explains one must keep pointing at the anomalies and failures in the old paradigm. Don’t waste time with reactionaries; rather work with active change agents and with the vast middle ground of people who are open-minded. Wastewater treatment operators, with their unique perspectives on treatment and large numbers in the industry, have the power to drive real improvement in primary treatment and be the change agents.

Misaligned goals led to the current paradigm.

WWTP Owners: Sustainably take in wastewater, remove the solids then return the separated water and solids to nature with a reliable, easy to operate system.

Consulting engineer: Make money by selling billable hours.

Clean Water Act Regulators: Restore and maintain the chemical, physical and biological integrity of the nation's waters.

Equipment manufacturer: Sell the most equipment for the highest price by producing low maintenance, easy to operate equipment that needs replacement every few years.

I want to tell a story, through the example of an attempt at primary treatment disruption, of how misaligned goals of the various market players make disruption difficult. Clear Cove recognized primary treatment has not changed significantly since humans started building wastewater treatment plants and the industry solution to regulation has been adding in layers of treatment from secondary biological treatment to tertiary filtration. How about a solution that removes as much of the solids and carbon at the start of treatment? Clear cove built and tested this type of system starting in 2008 at small, medium and large WWTP’s but today if you go to their website you get “Not Found The requested URL /municipal/harvester-sewage-treatment/ was not found on this server.”

What happened to Clear Cove and what can we learn from their attempt at disruption? I will tell the story of their three pilot projects aimed at radically improving the separation of solids during primary treatment Reducing the treatment load on secondary treatment would make WWTP’s easier to operate and reduce energy use. This future is possible but only with operators' ideas and wisdom.

3:45pm - 4:30pm

Optimizing Polymer Mixing and Activation: Following the Science

Jeff Rhodes

UGSI Solutions, United States of America;

Despite the wide-spread use of polymers in water and wastewater treatment and their associated high recurring expense, understanding exactly how to optimize polymer use in water and wastewater treatment is not well understood.  With many equipment options available to operators, it makes sense to start with the basics of polymer chemistry and then apply those principles to polymer activation equipment options.  This discussion will review the basics of polymer chemistry, goals of activation, the development of polymer mixing equipment and equipment configuration basics. 

 Factors such as charge site exposure, polymer hydration, application of mixing energy and the effects of dilution water will be detailed as they influence proper polymer activation.  Additionally, the impact of water quality attributes such as disinfectant residual levels and hardness on optimal polymer hydration are explored.  Given the industry trend of using reclaimed water for polymer mixing, it is crucial to understand the effects of residual chlorine, turbidity, and various dissolved ions.

Finally, the benefits of utilizing two-stage mixing - very high initial mixing energy followed by low and uniform mixing energy - are demonstrated by theoretical consideration and practical test data. Emulsion polymer systems with sufficient residence time have proven to provide a more efficient polymer solution. Lastly, both mechanical and hydraulic polymer activation systems will be analyzed to assess their efficiency and adherence to the principles of polymer activation previously discussed.  Included in this discussion are equipment features and the latest improvements that help ensure efficiency and reliability for utilities and treatment plant operators. 


Date: Wednesday, 15/Sept/2021
8:00am - 10:15amSession 22A: Innovation & Technology
Location: 110AB
8:00am - 8:45am

Installation, Startup, and Operation of World’s First Regenerable Resin System for PFAS Removal

Patrick McKeown. PE1, Steve Woodard. PhD1, Tim Gould2

1ECT2; 2Ahtna Engineering Services, LLC;

The United States Air Force Civil Engineering Center (AFCEC) is conducting on-going response activities to remove and remediate groundwater impacted by poly- and perfluoroalkyl substances (PFAS) at the former Pease Air Force Base in New Hampshire.

AFCEC responded by contracting with Wood Group PLC to conduct a side-by-side pilot test in 2016, comparing the performance of Emerging Compound Treatment Technology’s (ECT2) regenerable ion exchange (IX) resin and bituminous granular activated carbon (GAC). The regenerable resin system was selected for full-scale application, based on system performance and a lower overall lifecycle cost than GAC.

A 200-gpm system was provided to meet the primary project objective of producing treated water with combined PFOS plus PFOA concentrations below the 70 ng/l Health Advisory Level (HAL). The full-scale IX resin system was installed from fall 2017 through spring 2018.

The PFAS remediation system has treated more than 31 million gallons of groundwater having a total average influent PFAS concentration of 55 µg/l. The effluent quality from the IX resin system has been consistently non-detect for PFOS and PFOA, readily achieving compliance with the 70 ng/l HAL target.

Five successful resin regenerations have been performed to date. Operational modifications have been made to address and correct minor challenges with the distillation system, and regenerant recovery and super-loading processes have proven successful. The original superloading media is still operational, having removed and concentrated greater than 99.99 percent of the recovered PFAS mass, and therefore no PFAS waste has needed to be hauled off site to date.

8:45am - 9:30am

A Pilot Scale Evaluation of Coagulant Selection and Dose on HF UF Membrane Performance at the West Boise Water Renewal Facility

Dan Hugaboom1, Ryan Anderson2, Brad Jeppson1

1Carollo Engineers Inc, United States of America; 2City of Boise;

In 2019, the City of Boise completed a pilot study of tertiary coagulation and hollow fiber microfiltration and ultrafiltration (MF/UF) membrane technologies at its West Boise Water Renewal Facility (WBWRF) for phosphorus removal. The work was done to support planning for plant improvements required to comply with anticipated reductions in phosphorus discharge limits from the WBWRF.

The pilot study investigated the performance of a wide range of coagulants and membrane technologies to achieve two primary process goals:

  1. Tertiary treatment train effluent total phosphorous of less than 0.1 mg/L TP-P. Five coagulants were tested across a range of doses to meet the TP goal without overloading the membrane process with coagulated solids. Ferric chloride, ferrous chloride, alum, ACH and RE300 (cerium chloride) were evaluated to achieve a treatment goal of reducing TP from approximately 1 mg/L in the secondary effluent to <0.1 mg/L.
  1. Demonstrate reliable membrane performance. Membrane performance was evaluated using quantitative goals for maximum fouling rates, residuals production and off line chemical cleaning frequency. Three different membrane systems, each with unique design and performance characteristics were evaluated for this application. They include pressurized (cartridge style) UF membrane and two submerged (vacuum driven) systems. The experimental matrix allotted significant amount of time for optimizing backwash, air scour, cross flow and chemical cleaning strategies as well as a range of flux rates.

Below doses of about 5 mg/L (as product), membrane fouling was low and chemical cleaning cycles met goals for maximum allowable frequency, however filtered effluent TP did not consistently meet the goal of <0.1 mg/L. As required dosages increased to meet filtrate TP goals, more energetic and frequent cleaning strategies were necessary to meet membrane performance goals. This presentation will include a detailed analysis of phosphorus removal across the range of coagulants, as well as membrane process performance.

9:30am - 10:15am

The Facility of The Future for the Utility of the Future

Layne McWilliams

Cascade Energy, Inc., United States of America;

The “Utility of the Future” program has given a name to the management and organizational principles that will be needed for wastewater organizations to thrive in the years to come. Features include professional training programs, labor recruiting programs, CMMS programs, improved public and customer relations, collaborative working relationships with regulators, resiliency for extreme events, energy management programs, etc.

But, what about the physical plant? In many ways, most of the new plants being built today would look familiar to a time-traveling engineer from the 1950’s. Part of this is expected – for very good reasons, our industry is slow to embrace new ideas until they are proven out through many years of full-scale use.

My hypothesis is that our industry could create some VERY different facilities if the design requirements were changed. I propose to collect, organize, and share ideas from volunteers from at least 10 separate PNCWA-member engineering firms and vendors who will help answer this question: If you were asked to design a 5 MGD, greenfield facility located near Coeur d’Alene, to meet a 5/5/1 standard, year-round, that would minimize the total carbon footprint of its construction and operation over 30 years, what features would you include? You must select from materials, equipment, and processes that are currently commercially available somewhere in the world, though it does not need to be used currently in the wastewater sector. Ideas for collection and disposal alternatives will also be welcomed.

For the conference, we will present a design summary of each major process area and briefly describe the alternatives and the reasoning for them suggested by the survey participants. The calculations and assumptions for embedded and operational CO2e will be summarized along with the pros and cons of each alternative. The names of volunteers will be shared but will not be associated with specific solutions.

The over-arching goal of the presentation is to provide new ideas to the audience and show what might be achieved when efforts are focused not on lowest first cost but on lowest ultimate impact to the environment.

10:30am - 12:00pmSession 22B: Resource Recovery
Location: 110AB
10:30am - 11:15am

Applied Planning for Pocatello's Biosolids Reuse and Recovery

Nick Smith1, Skyler Allen2

1Stantec Consulting Services Inc., United States of America; 2City of Pocatello, ID; ,

The City of Pocatello, ID has been recovering, land applying and reusing its Class B treated biosolids for decades on nearby agricultural lands. The biosolids treatment and handling system consists of mesophilic anaerobic digestion of thickened primary and secondary sludge, followed by lagoon storage and spring/summer liquid sludge hauling to both City owned and leased land. In the last few years, local growth and associated loading to the Water Pollution Control Facility (WPFC) have increased to the point where the lagoon is often overloaded in late winter through early summer. This situation creates challenges to the operations of the WPCF as the biosolids recirculate back into the liquid stream. This solids overload results in costly and hectic lagoon dewatering efforts, sub-optimal treatment performance and increases the risk of NPDES permit violations. Faced with this challenge, coupled with the desire for long term biosolids planning, the City selected the Stantec/Keller team to address this problem as part of the 2021 Facility Plan update. To properly address the biosolids issue, the team implemented a decision-making process for both solids handling and solids reuse or disposal. The first evaluation included a decision to either expand the biosolids lagoon system or move toward solids dewatering. The second decision determined whether to continue the existing land application of liquid sludge, move to dewatered sludge land application, enhance the biosolids to a Class A through composting, or shift toward landfill application. The results are in, the decisions have been made and the City is moving forward with making the recommended improvements to provide the best solution and end use for this valuable City resource.

11:15am - 12:00pm

Novel Alternative Management of Data Center Industrial Wastewater

Brett Converse1, Shae Talley1, Scott Coleman2

1J-U-B Engineers; 2City of Umatilla Oregon; , ,

Data centers offer economic drivers attractive to communities able to meet utility demands. These industries have large electrical demands to power associated computer equipment which are converted to heat and must be evacuated. Data centers using evaporative cooling require large amounts of water which is evaporated or discharged as industrial wastewater when constituent concentration or temperature prohibits continued use in cooling towers. The volume of water used, the volume of water evaporated, the volume of water discharged, and constituent concentration therein will depend on the quality of source water, climatological conditions and internal management. Water and wastewater service providers must understand the demands of data centers and plan for meeting those demands prior to agreeing to serve. In 2013, the first data center was constructed within city limits at the City of Umatilla, Oregon. After the data center became operational, industrial wastewater was discharged to the City’s wastewater treatment plant when the ambient temperature began to climb in the springtime. When the temperature reached over 100 degrees, the City experienced a 65 percent increase in wastewater flow and corresponding dilution of most influent constituent concentrations. As the industrial development continued, the City had concerns over managing projected flows from future data center expansions and began planning to meet service demand. After investigating alternatives, the City decided to pursue discharging the industrial wastewater directly to a water of the state via a national pollution discharge elimination system (NPDES) permit. The presentation will focus on the City’s experience collecting, treating, permitting and disposing of the data center industrial wastewater and associated benefits: additional irrigation water, lower fees and sustainability.