Conference Agenda

Overview and details of the sessions of this conference. Please select a date or location to show only sessions at that day or location. Please select a single session for detailed view (with abstracts and downloads if available).

Session Overview
Date: Monday, 13/Sept/2021
7:00am - 8:15amBreakfast—Monday Breakfast
Location: Room 400A
7:00am - 5:00pmSpeaker Ready Room is Open
Location: Room 110C1
7:00am - 6:30pmRegistration Desk is Open
Location: Main Lobby
8:30am - 10:00am00B Opening: Keynote Presentation - Livestream
Location: Room 400BC

Dr. Dan Prinzing, Executive Director of the Wassmuth Center for Human Rights & Tai Simpson, Organizer for the Indigenous Idaho Alliance

10:00am - 10:30amMonday Morning Break
10:30am - 12:00pmSession 01A: Planning & Regulatory - Livestream
Location: Room 400BC
10:30am - 11:15am

One Doesn’t Just Walk into a Proactive Rehabilitation Program: SPU’s Strategic Quest.

Caroline Barlow1, Julie Crittenden1, David Gordon2

1Seattle Public Utilities; 2Blue Cypress Consulting, LLC;,

Seattle Public Utilities (SPU) entered into a Consent Decree in 2013 to reduce combined sewer overflows and work towards eliminating sanitary sewer overflows. A major cause of sewer overflows in Seattle is structural failure. It is also a growing concern given that the City’s 1,420 miles of sewer pipes have an average age over 80 years and pipe rehabilitation has been historically underfunded. SPU increased pipe inspection and rehabilitation funding upon signing the Consent Decree, but recognized that there would need to be a holistic look at pipe rehabilitation to ensure long-term system reliability.

This presentation walks through SPU’s work to develop and secure funding of a long-term rehabilitation plan for its aging sewer system. This planning effort was not a single event, but a concerted effort through a series of strategic projects over four years; with each strategy building on one another. Participants will learn about SPU’s strategies for pipe inspection, condition evaluation, risk assessment, capital investment, and implementation planning. Particular focus will be spent on key aspects of the process such as incorporating service equity, increasing efficiencies, securing staffing for implementation, and preparing for adaptive management. This presentation will leave participants with a roadmap for how to move from a reactive to proactive rehabilitation program. It was not a simple and quick solution, but has set SPU up for reliable and sustainable long-term sewer service.

11:15am - 12:00pm

Klamath Falls Evaluates What to Do With Its Final Effluent

Randy Zollinger, Nigel Beaton, Eva Steinle-Darling

Carollo Engineers, Inc., United States of America;,

In response to lower nutrient and temperature limits for continued river discharge, the City of Klamath Falls evaluated 100% reuse against continue river discharge. The City is looking for economical, long-term strategies that beneficially uses City’s final effluent, offers some regulatory certainty and promotes partnerships in addressing Upper Klamath River water supply and water quality concerns. This presentation will discuss reuse to augment agricultural irrigation needs involving the US Bureau of Reclamation, the Klamath Drainage District and the Lower Klamath National Wildlife Refuge. Under this reuse alternative, the City would divert its final effluent over the entire year to the Klamath Drainage District who in turn would beneficially use and manage the final effluent to meet irrigation demands of local growers and to help the Lower Klamath National Wildlife Refuge maintain habitat for migrating waterfowl. Reuse water management plans, permitting strategies and needed improvements to the City’s existing Spring Street Wastewater Treatment Plant to support a 100% reuse option will be reviewed and compared to a continued river discharge alternative. Critical factors in alternative selection will be discussed so other Cities facing similar water quality challenges may benefit from City of Klamath Fall’s experience.

10:30am - 12:00pmSession 02A: Social Equity - Livestream
Location: 120AB
10:30am - 11:15am

How Do We Make Outreach More Equitable? A Case Study at Murraysmith + Quincy

Maricris "Mari" Orama, Sage Ebel

Murraysmith, United States of America;,

It is no secret that STEAM fields lack the diversity and inclusion of the communities they serve. Many individuals and organizations are working hard to develop plans for increasing racial and gender equity within their fields. STEAM Outreach plays a significant role in supporting long-term societal goals of increasing STEAM literacy and diversity within our STEM workforce.

STEAM Outreach has been found to provide communities—particularly students, parents, and teachers—with opportunities to engage in ways that are relevant, educational, and inspirational. COVID-19 stay-at-home orders and remote schooling have posed both challenges and advantages for STEAM Outreach. Ultimately, without an intentional focus on equitable structure and practice within an outreach program, students in underserved communities will continue to have limited access and exposure to knowledge of STEM fields, technology, resources, and a comprehensive STEM educational experience (Avendano et al, 2018; Boyce, 2017).

What can we as professionals in the engineering industry do to build and foster more equitable STEAM communities? How do we structure our Outreach Programs to focus on equity?

This presentation explores the steps taken at Murraysmith + Quincy to improve its STEAM Outreach program. We will discuss: 1) the significance of STEAM versus STEM; 2) the challenges and advantages posed by remote learning and STEAM outreach; 3) the restructuring of our program; 4) lessons learned and next steps; and 5) pertinent conclusions and recommendations for other companies looking to initiate more equitable outreach programs.

11:15am - 12:00pm

Walking a Mile in Our Communities' Shoes

Nicki Pozos, Jessie Maran

The Formation Lab, United States of America;,

Wastewater professionals often struggle to translate equity principles into their everyday work. At the heart of this struggle is a lack of understanding—how does our work interact with the life conditions of the communities we serve? This interactive session will explore three scenarios relevant to utilities: basement flooding, trust in drinking water, and construction impacts. Attendees will explore how socio-economic resilience, disenfranchisement, and transportation access affect our lived experience.

10:30am - 12:00pmSession 03A: Wastewater Process: Planning & Compliance - Livestream
Location: Room 430AB
10:30am - 11:15am

What? When? How Sensitive? Evaluating Capacity At King County’s Three Regional Plants

Patricia Tam1, Henryk Melcer1, John Conway2, Tiffany Knapp2

1Brown and Caldwell, United States of America; 2King County Wastewater Treatment Division, United States of America;

Virtual Speakers

To protect public health and deliver reliable clean water services while accounting for changes in the service area, King County Wastewater Treatment Division (WTD) updates its projections of wastewater flows and loads every 10 years and evaluates their impact on overall treatment plant capacity. In 2014, WTD noted that influent loads were increasing more quickly than flows. Recent water conservation efforts have reduced the amount of potable water used on a per-capita basis. These reductions in water use directly impact wastewater flows, but not loads. As a result, influent concentrations are higher than the design values. Comparing the flow and load projections with the current rated capacities for each of the County’s three regional plants (South, West Point and Brightwater) shows that the rated flow capacities will be reached after 2035 whereas the rated loading capacities will be exceeded within the next 10 years.

To identify potential capacity limitations and their timing by process within the three plants, WTD undertook an in-depth capacity evaluation for all major processes. The evaluation accounts for plant-specific wastewater characteristics, existing regulatory requirements, operating configurations, and process performance. Sensitivity analyses were conducted for each plant to assess the influence of various critical parameters on unit process capacities. Some unit process capacities were found to be highly sensitive to changes in certain parameters. For example, at West Point, capacity of the aerators in the high-purity oxygen aeration basins could change significantly at different target dissolved oxygen concentrations. At both West Point and Brightwater, taking one digester out of service for maintenance was found to have significant impact on the timing of the digester capacity limitation. This analysis provided WTD with an understanding of the timing for when unit process capacity limitations may be experienced to inform system-wide treatment planning.

11:15am - 12:00pm

Dairy Cows Speak a Different Language: Jerome’s Journey to Wastewater Compliance

Jason King1, Eric Roundy1, Dade Pettinger2

1Keller Associates, Inc., United States of America; 2City of Vancouver, Washington;,,

Jerome's wastewater treatment plant is unique in that several dairy products processing facilities deliver most of the loading to the treatment plant. This dairy processing brought significant revenue to the City, at the cost of large fluctuations and high loading at the treatment plant. Seeking resolution to repeated discharge permit violations caused by the high loadings, the City and the Environmental Protection Agency entered a consent decree. The City of Jerome and Keller Associates worked quickly to assess the treatment system and evaluate compliance options for the best treatment of the high-strength wastewater. A phased approach to improvements allowed the City to promptly reduce additional non-compliance risks while further upgrades were designed and constructed.

Phased upgrades at the treatment plant were completed approximately a year ago. These upgrades incorporated approximately five years of construction and a total cost of about $35 million – the largest project in the City's history. This wastewater treatment project successfully reused/rehabilitated a significant portion of the existing plant and included the construction of 24 new treatment/conveyance structures. Plant compliance during construction was challenging as all unit processes were disrupted. This presentation will focus on the approach and results – during design, construction, and post-construction – that addressed Jerome's high-strength dairy wastewater and prepared them for sustained compliance.

10:30am - 12:00pmSession 04A: Resource Recovery
Location: 410ABC
10:30am - 11:15am

Beyond Net Zero – Reaching the Next Level of Renewable Energy through Beneficial Use of Food Waste

Kristen Jackson1, Alan Johnston2, Matt Noesen1, Jodie Binger1, Dave Parry1

1Jacobs; 2The City of Gresham, Oregon;,,

The City of Gresham (City) Wastewater Treatment Plant (WWTP) is a 15 MGD facility located east of Portland, Oregon. The plant accepts and co-digests fats, oil, and grease and beneficially uses their biogas to fuel a combined heat and power system to achieve energy neutral status and they are evaluating how to go beyond net zero. The existing two mesophilic anaerobic digesters at the facility are currently at capacity and in need of an expansion to accommodate projected future loadings for city growth as well as to provide redundancy.

A recently adopted policy by Metro (regional entity) requires mandatory segregation, collection, and alternate processing (not landfilling) of food waste that is generated by businesses within the Portland metropolitan area. The City conducted a study to explore the financial payback options for a digestion expansion project that could fulfill the City’s capacity needs, accept food slurry from Metro’s food waste program (or other liquid organic waste sources), and beneficial use of the additional biogas produced.

The study assessed potential cost and non-cost benefits and impacts associated with additional liquid organic waste loading on the WWTP, digestion alternatives, sidestream recycle loading to the liquids treatment, solids dewaterability, biogas production, and biosolids end use. The study included a business case evaluation considering economic, environmental, social, and operational impacts to assess the favorability of pursuing the selected alternative. Finally, the study included a conceptual design for the selected alternative.

The study has shown that the City could spend 16 million dollars and construct a third mesophilic digester for capacity needs and not accept additional feedstocks nor receive a payback on the investment. Alternatively, the City could spend approximately 30 million dollars to convert two existing digesters to thermophilic technology, construct a third thermophilic digester, expand feedstock receiving, expand cogeneration, and obtain a payback on investment under 10 years by utilizing State incentive programs. The City is planning to conduct a predesign to further refine liquid organic waste availability, revenues and costs, and funding sources for the project.

11:15am - 12:00pm

Linking Anaerobic Digester Microbiomes With Resistance To Organic Overloads

Ashley Berninghaus, Tyler Radniecki

Oregon State University, United States of America;

Anaerobic co-digestion has become a popular option to increase biogas production, thus increasing recapture potential, with grease trap waste, or FOG (fats, oils, and greases), showing the highest methane production potential. In order to ensure reactor stability and optimal performance, the correct microbiome composition is essential. However, it is currently unknown what microbiome compositions are optimal for co-digestion nor what operational parameters are most effective at creating these optimal structures. This work monitored nineteen full-scale anaerobic digesters, at six separate facilities, monthly for one year to link operational characteristics with microbiome composition. Of the nineteen digesters studied, three perform FOG co-digestion, four perform co-digestion with biodiesel wash water, one is fed only TWAS (thickened waste activated sludge), and the remaining eleven are fed primary sludge and TWAS. Microbiome composition was analyzed using 16S rRNA amplicon sequencing. Operational data from each of the full-scale facilities (including pH, alkalinity, volatile fatty acids, detention time, temperature, total and volatile solids, free ammonia, organic N, dissolved P, organic P, chemical oxygen demand, and gas production) was examined to determine their influence on microbiome compositions.

Batch resistance assays were created to link microbiome compositions with digester functionality in response to organic over loadings. For each full-scale anaerobic digester tested, twenty-five 100 mL batch anaerobic digesters were used for batch resistance assays. Five batch anaerobic digesters were ran as digestate-only controls, and the remaining twenty were fed 1 mL, 5 mL, 10 mL, and 20 mL of canola oil (in quintuplet). The rates of methane production and methane content of the biogas were used to calculate the functional resistance of each full-scale anaerobic digester. The batch resistance assays were performed in winter and summer to account for seasonal variations in full-scale plant operation and microbiome compositions.

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.

10:30am - 12:00pmSession 06A: Facility Operations
Location: Room 130
10:30am - 11:15am

Operations and Maintenance Initiatives in the Water Environment Federation

Chris Maher

Clean Water Services, United States of America;

Virtual Speakers

The Water Environment Federation (WEF) sets forth Critical Objectives and Strategic Goals in order to achieve its vision of “A community of empowered professionals creating a healthy global water environment.” One group of the envisioned empowered professionals is facility operations and maintenance (O&M) staff. A number of programs have been initiated by WEF to support and address the issues currently facing the O&M sector of the industry.

As a whole, these programs attempt to focus on recruitment and retention of operators, education and training for operators and operator trainers, recognition for operators, certification exams, and certification reciprocity. Programs are executed through WEF committees and task forces such as the Operators Advisory Panel (OAP), the Plant Operations and Maintenance Committee (POMC), and the House of Delegates (HOD).

The success of these programs can be limited in several ways. First, many O&M staff are only registered at the member association (MA) level, and therefore are unaware of and have no access to the resources available at Second, the activities of these committees are guided to some degree by the personal views and experiences of committee members, and may not necessarily align with issues prioritized by O&M staff. Third, O&M certification is handled by the states as is approval of continuing education units (CEUs) needed to maintain certification. The difficulty in issuing CEU accreditation devalues the national level education resources.

The Covid-19 pandemic has halted in-person trainings but affords opportunities in distance learning and greater exchange of ideas that we must use to our advantage.

This session, presented by the immediate past chair of the WEF POMC, will introduce the general structure of the WEF groups addressing O&M issues and highlight the major issues of concern. The resources and benefits of full WEF membership will be demonstrated. The session is then intended to proceed to an extended (15-20 minute) interactive discussion with the audience (hopefully dominated by O&M staff and managers) that will garner feedback about the value of various programs and initiatives and inform what issues truly are of high concern to O&M staff.

11:15am - 12:00pm

“Plan the Work, Work the Plan” Start up of the Tri-City Solids Handling Improvement Project

Jeff Stallard

Water Environment Services, United States of America;

Virtual Speakers

In 2015, Clackamas Water Environment Services (WES) kicked off a project to completely overhaul and expand the solids facilities at the Tri-City Water Resources Recovery Facility (TCWRRF). The project constructed a new 1.3 million gallon digester, dewatering facilities and a combined heat and power system. Two existing digesters are also being upgraded. During the project development, WES operations staff was integral in developing the construction constraints included in the construction bid package. To accommodate the constraints identified, the start-up of the project was separated into two phases. Phase 1 of start-up, was completed in December of 2020, included the new digester, centrifuges, polymer systems, boilers, and dewatering feed tank. Phase 2 of the project, scheduled to begin in April 2021, will include making the upgrades to the two existing digesters, addition of a digester feed tank and replacement of the co-generation system.

Because digestion facilities must remain online and reliable during construction, significant coordination effort between engineering, operations and construction team members has been required throughout the project. This presentation will provide an overview of the project and the challenges there were being experienced prior to this project, it will cover in detail the approach to planning and coordination between the operations staff, contractor, and engineer during design, construction, and execution of both phases of start-up. The presentation will include lessons learned from all three perspectives as well as an update on the operational performance of the new facilities.

12:00pm - 1:15pmLunch—Monday Networking Luncheon
Location: The Grove Plaza
1:00pm - 2:00pmRecorded Facility Tour
Location: 420 AB

Piece County Tour 1:00pm - 2:00pm

Pierce County’s Cascadia Wastewater Treatment Plant is a state-of-the-art MBR facility, serving the Employment Based Planned Community of Tehaleh in Bonney Lake Washington. Currently operating in the midst of a phased construction plan, the plant treats an average of .35 MGD to the highest standards in the Pacific Northwest, with plans for much more!

Some of the unique highlights of Cascadia include: 

    • A phased approach to construction that provides capacity as the community is built out.
    • Microdyne Flat sheet membranes producing superior effluent quality.
    • Currently operating with liquid stream processes only.
    • Built with a public/private partnership that provides an innovative solution to construction and operation issues. 
    • Intended as a closed loop community.   

Follow along with Jon Kercher as we tour the facility and learn more about what makes Cascadia and Tehaleh unique.

1:15pm - 2:45pmSession 01B: Risk Assessment/Stormwater - Livestream
Location: Room 400BC
1:15pm - 2:00pm

Boise’s SARS-CoV-2 Wastewater Dataset and the Future of PCR Testing at WRFs

Haley Falconer1, Tyson Schlect2, Kyle Patterson1, Dave Clark2, Michael Kasch2

1City of Boise; 2HDR;,

Viewing wastewater as a resource opened pathways of innovation previously unforeseen. The SARS-CoV-2 pandemic amplified a similar paradigm of innovation in the science of Wastewater-Based Epidemiology (WBE). In May of 2020, the City of Boise began sampling wastewater at both of its Water Renewal Facilities (WRFs) to test for SARS-CoV-2 virus using quantitative polymerase chain reaction (qPCR). On June 17th the City began daily sampling and continued through two infection peaks. The City’s dataset is one of the most robust datasets in the country for WBE.

RT-qPCR quantifies copies of virus RNA in the wastewater matrix. The City contracted with the University of Missouri to perform qPCR. Virus quantities in the wastewater ranged from 50,000 to 1,395,000 copies per liter. Puro virus recovery was used as a proxy indicator of the relative amount of virus recovered through the qPCR method and ranged widely from 2 to 82 percent, with an average of 11 percent. Genetic sequencing was also used to perform early screening to detect if SARS-CoV-2 variants were present.

Visualizations of the data show clear correlation with number of confirmed cases in Ada County. Numerical correlations were weak because of daily variability, however the visual correlation revealed that during periods of infection rate increases the wastewater signal provided four to seven days advanced notice prior to case report date. The City coordinated with Centers for Disease Control, Central District Health, and St. Luke’s Hospital to maximize the benefit of WBE.

Laboratory layouts and equipment specifications were evaluated for conducting qPCR molecular testing at WRF lab facilities. Experience designing 26 public health labs in the United States was leveraged to customize the “unidirectional flow of sample” design approach within the WRF laboratory context.

Using qPCR at WRFs will continue to expand the paradigm of wastewater as a resource. The current application of qPCR for SARS-CoV-2 testing reveals that indicator virus testing for disinfection (such as adenovirus and norovirus), identification of specific organisms for biological nutrient removal within WRFs, and early detection of future diseases in wastewater are destined to become integral parts of ongoing WRF operations in the modern era.

2:00pm - 2:45pm

Beavers Improve Water Quality in an Urban Watershed

Katie Holzer

City of Gresham, Oregon, United States of America;

Beaver populations have been returning to urban watersheds in the Pacific Northwest, bringing with them both benefits and challenges. To better understand the effects on local watersheds, we conducted several studies of beaver activities within the city of Gresham, Oregon. We looked at pollutant removal efficiencies in a large stormwater treatment wetland with and without beaver activity, assessed the effect of beaver dams on stream temperatures, and documented the physical and biological changes to stream channels near dams. We found that pollutants of concern were generally removed more efficiently when beaver dams were present in the treatment wetlands. This is likely due to the water being filtered through the dams which are repaired after each storm. The effects of dams on stream temperatures varied depending on site characteristics, but all dams created ponds with temperature heterogeneity and stratification. Dams on higher order streams sometimes reduced overall stream temperature by pulling water from the entire stratified water column and increasing hyporheic flow. Within just a few years of beaver activity, several sites experienced increased stream complexity with new gravel bars, side channels, and braided streams. We also found increased macroinvertebrate diversity in the relatively sediment-free cobbles downstream of dams. These findings demonstrate multiple benefits of beavers in urban watersheds. After communicating these benefits to stakeholders, we have been working with beaver experts to adapt our systems to find ways to protect infrastructure while coexisting with beavers through targeted use of technologies such as pond levelers, culvert fencing, and tree protection.

1:15pm - 2:45pmSession 02B: Workforce Development - Livestream
Location: 120AB
1:15pm - 2:00pm

Be the Catalyst: How Individuals Can Shape an Organization and Transform the Water Workforce

Shelby Smith, Vicky Hollingsworth

Brown & Caldwell, United States of America;,

Virtual Speakers

The water industry is undergoing a significant cultural transformation in response to social equity challenges and a rapidly evolving workforce. The future workforce has different priorities, backgrounds, and drivers from that of the past and present. Workforce retention challenges emerge due to organizational cultures where employees feel unsupported, disconnected, and inauthentic. Companies that do not evolve to foster inclusive work environments are less competitive and innovative, struggle with recruiting and retaining talent, and ultimately face obsolescence in the water industry. But individual actions at all organizational levels can break down barriers to inclusion and build more desirable work environments.

In 2018, Brown and Caldwell (BC) employees sought to create a more inclusive, open, and diverse work environment that provided them with a space to connect, be authentic, find community, and learn. Out of this movement, employees formed the Women at BC Employee Network Group (ENG), which created an inclusive and safe space for women to share their stories. This first ENG sparked broader conversations around diversity, equity, and inclusion. New ENGs quickly followed – each centered around different BC employee experiences and challenges. BC leadership listened and advocated based on these conversations. The company established the 10 Commitments to Balance and Belonging, which set the long-term plan to transform, operationalize equity into business and hiring practices, and challenged the organization to go beyond current industry limitations.

This presentation will dive into the story behind some of the individuals who became the spark that accelerated a cultural transformation in the workplace. Organizations that create space and establish platforms for employees to be authentic and vulnerable will drive allyship, diversity, and inclusion. These key ingredients create resilient organizations where employees can thrive, innovate, and better serve their communities.

2:00pm - 2:45pm

Sharing Your Privilege – the Criticality of Advocacy in Diversifying the Pacific Northwest Water Industry

Rob Lee

Leeway Engineering, United States of America;

Virtual Speakers

The face of the Diversity, Equity, and Inclusion (DEI) movement here in the PNW has largely been women and people of color, and rightfully so in many cases. But this can and has led to cases of fatigue, frustration, and even challenging accusations such as “self-promotion”.

As the topic of diversity has become more prominent and as the numbers are starting to be documented about the genuine benefits of diversity, a challenge that has become evident is the critical role that must be played by those who have privilege and the power to enact change.

This session will begin with an introduction of the importance and benefits of diversity and a brief introduction to the ways that PNCWA, as a volunteer organization, is taking steps to advance Racial and Social Justice. The remainder of the time will be given to a panel discussion by advocates in the industry and representatives from several municipalities including the City of Boise, the City of Portland, King County, and Seattle Public Utilities. This panel will provide numerous viewpoints regarding privilege and how anyone, regardless of gender, ethnicity, or orientation, has an important role to play in progressing our industry for positive change.

1:15pm - 2:45pmSession 03B: Wastewater Process: Nutrient Removal - Livestream
Location: Room 430AB
1:15pm - 2:00pm

How a Full-Scale Pilot Guided a WRRF Path to Chemical P Removal

Chris Machado1, Jamie Safulko2, Greg Farmer2, Shelley Trujillo1, Nicole Stephens1

1Stantec, United States of America; 2City of Englewood - South Platte Renew;

South Platte Renew (SPR) is the third largest water resource recovery facility (WRRF) in Colorado, with a capacity of 50 million Gallons per day (MGD). SPR’s discharge to the South Platte River is regulated by the Colorado Department of Public Health and Environment (CDPHE). CDPHE set a regulatory roadmap for nutrient removal with intermediate steps for compliance including a 10-year Voluntary Incentive Program (VIP). This program allows the SPR to voluntarily treat nitrogen and phosphorus to levels below permit requirements and to earn compliance credits (i.e., years) towards future more stringent regulations.

To take full advantage of the VIP, SPR is implementing a chemical phosphorus removal (Chem-P) process to achieve effluent total phosphorus below 0.7 mg/L. SPR took a comprehensive approach to evaluate design options for Chem-P implementation including full-scale piloting. The pilot used existing ferric sulfate storage/dosing facilities. The ferric sulfate dose was varied in three phases through five months: (I) initial baseline, (II) ramp-up, (III) stabilization at optimum dose. The pilot was conducted by a team of operators and engineers. Close collaboration and monitoring were critical for the successful completion of the pilot. Plant profiles of phosphorus, nitrogen, total suspended solids, alkalinity, and pH were monitored. Spot sludge samples were collected for vivianite analysis through x-ray diffraction.

The full-scale pilot demonstrated that a dose of 40 mg/L is required to reach the desired effluent total phosphorus concentration of 0.7 mg/L as P. It also indicated an increase in solids production of over 10 percent for the current 18 MGD average flow. Furthermore, the results indicated that depending on the overall plant operation, the impact in alkalinity may be significant to meeting effluent pH limits. Nitrification was not significantly affected during the full-scale pilot, however a small reduction in performance during high load hours of the day was observed.

Conversion to full biological phosphorus removal can be a costly option depending on the overall existing facility process design. Chem-P is still a common and cost-effective alternative to many WRRFs. This presentation will describe the approach and lessons learned in the full-scale chemical P removal pilot at the SPR WRRF.

2:00pm - 2:45pm

Pilot Testing Nuvoda’s Mobile Organic Biofilm at the Edmonds WWTP

Tom Giese1, Pamela Randolph2, Li Lei3, Jason Calhoun4, Dr. Mari Winkler5, Bao Nguyen Quoc5

1BHC Consultants; 2City of Edmonds, WA; 3Jacobs; 4Nuvoda; 5University of Washington;,

Like many other WWTPs in the Puget Sound region, the Edmonds WWTP will be facing nitrogen limits under the Nutrient General Permit from the Washington State Department of Ecology. The City of Edmonds WWTP is a conventional activated sludge process originally designed for oxidation of BOD with a mean-cell residence time typically between 3 and 5 days. A large amount of additional tankage would be required to upgrade the conventional activated sludge process for nitrification and denitrification at considerable expense and would present major challenges in creating space for such an addition. Rather than wait until forced to face this challenge, the City has decided to proactively explore promising alternatives. One such alternative is Nuvoda’s MOB™ (Mobile Organic Biofilm) process. The City of Edmonds, Nuvoda, BHC Consultants, Jacobs, and the University of Washington worked together to first assess the feasibility and potential effectiveness of this technology, followed by conducting a full-scale pilot test. Topics of this presentation will include:

  • Overview of the Edmonds WWTP
  • Why Nuvoda MOB™?
  • Overview of Nuvoda MOB™ technology
  • Overview of the full-scale pilot system
  • Overview of pilot system performance
  • Future application at the Edmonds WWTP
1:15pm - 2:45pmSession 04B: Energy Recovery
Location: 410ABC
1:15pm - 2:00pm

The Future of Meeting Permit with Energy Efficient Operations is Here

Wendy Waudby

Cascade Energy;

While energy hasn’t been on everyone’s radar in the past, thinking about energy use and ways to operate more efficiently is becoming more common. Many WRRFs have made no and/or low-cost operational changes to save energy without sacrificing water quality. Some have overcome barriers including the “this is the way we’ve always done it” thinking. Hearing success stories about facilities who have made small changes that led to significant energy savings might just be the help you need for your facility. Even folks who think their facilities are already optimized have found ways to save energy through strategic energy management. This presentation will focus on typical energy saving opportunities at WRRFs. Real world examples of projects implemented in the Pacific Northwest will be shared.

2:00pm - 2:45pm

Lewiston, Idaho Revamps their Aeration Basins to Save Energy and Improve Process Control

Curtis Butterfield, Eric Roundy

Keller Associates, Inc., United States of America;,

Lewiston, Idaho's wastewater treatment plant dates back to the 1950s, and surprisingly several of the original components are still in operation today. Although the equipment had been maintained, several equipment failures, and the associated emergency repairs, opened the City's eyes to the need for additional investment. One of the largest expenses for the facility was the aeration basins. The City utilized coarse bubble diffusers and controlled the aeration using manual operator adjustments. Additionally, the aeration capacity was insufficient, leading to several process upsets.

Over the past few years, the City made several critical decisions to improve its aeration basin system. Their approach eventually led to the construction of a new treatment process configuration within the existing basins. Additionally, the mixing, aeration, and aeration controls were all replaced to reduce energy usage and improve process control. The improvements, including compressed gas mixing and ammonia-based aeration control, have recently started up on the approximately $35 million project. This presentation will discuss the steps the City went through, their decision-making procedure to select the equipment, and the process and energy improvements that have been observed.

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.

1:15pm - 2:45pmSession 06B: Facility Operations
Location: Room 130
1:15pm - 2:00pm

Creating an Electronic O&M Manual for Pierce County’s Chambers Creek WWTP

David McBride1, Molly Bray1, Amanda Summers2

1Brown and Caldwell; 2Pierce County Planning and Public Works;,,

Virtual Speakers

Plant operations and maintenance manuals are often voluminous, stored in cumbersome hard copy binders, or saved as a multitude of electronic files which must be separately opened and browsed, and often neglected because they are difficult to update contemporaneously.

The Pierce County Project Team collaborated to create an IT solution for the operation and maintenance documentation needs of the recent Chambers Creek Regional Wastewater Treatment Plant Expansion (CCRWWTP). The team envisioned and executed an online electronic operations and maintenance (eO&M) manual. The eO&M consolidates and integrates all content related to the plant expansion, including engineer’s technical operations manuals, original equipment manufacturer (OEM) O&M manuals, record drawings, SCADA control modules, emergency response protocols, and plant related ancillary libraries. The eO&M is hosted on Amazon Web Services (AWS) and utilizes the OMS-Connect software platform. The CCRWWTP eO&M was structured as an evolving, living document designed to be appended by the County.

This presentation will provide an overview and online demonstration of the Pierce County CCRWWTP eO&M, discussing functionality, enhanced user experience, lessons learned, and tips and tricks for future eO&M authors. Modernizing O&M Manuals is important to sustained utility operations in the information age.

2:00pm - 2:45pm

CFD Modeling for Trickling Filter/Activated Sludge Secondary Clarifier Optimization

William Martin1, Alonso Griborio1, Steve Celeste2, Jue Zhao2, Victoria Lopez Boschmans1, Paul Pitt1, Marc Solomon1

1Hazen and Sawyer; 2City of Salem, OR;,

Clarifier CFD modeling is relatively common, however, most secondary clarifier studies are conducted in an activated sludge application. Trickling filter effluent (TFE) has different characteristics than conventional activated sludge. To the knowledge of the authors, a similar case study to the one presented here for the evaluation and optimization of TF clarifiers has not been presented before. This study is unique and presents a detailed analysis of settling and flocculation properties of TFE and the application of secondary clarifier CFD modeling to establish clarifier capacity and identify optimization strategies.

The City of Salem’s Willow Lake Water Pollution Control Facility (WLWPCF) has a permitted capacity of 35-mgd average dry and 155-mgd design peak wet weather flow. The City budgeted for clarifier rehabilitation due to ageing mechanical equipment but desired to understand clarifier capacity limitations and evaluate whether modifications could expand existing available capacity.

Hazen conducted stress tests and developed calibrated CFD models for the secondary clarifiers. Model calibration was based on an extensive clarifier testing protocol to simulate peak clarifier loadings, characterize sludge settleability and flocculation properties, and evaluate performance. This work included field testing, zone settling, flocculation and dispersed solids testing.

After development of the CFD models, the clarifiers were evaluated to determine available capacity with the current geometry and mechanism type. Optimization strategies such as the addition of energy dissipating inlet wells, modifications to the flocculation well sizing, and the addition of baffling were evaluated. The City used these results to tailor capital planning for clarifier rehab projects and re-evaluate wet weather capacity and operating strategies at the WLWPCF. Based this work, improvements were identified to potentially expand the combined clarifier peak flow capacity from approximately 105 mgd to over 140 mgd.

2:00pm - 3:00pmTours: Lander Street Water Renewal Facility
Location: 420 AB

Lander Street Water Renewal Facility hosted by Jesse Hartman

The Lander Street Water Renewal Facility (LSWRF) is in Northwest Boise near State Street and Veterans Memorial Parkway near the Boise Greenbelt.  Lander Street was built in 1948 and currently treats 10-12 million gallons each day. 

LSWRF is comprised of the following treatment processes:

  • Preliminary Treatment: Screening and Grit Removal
  • Primary Treatment: 5 Primary clarifiers with 2 operated as in-line primary fermenters for VFA production
  • Secondary Treatment: Step-Feed Plug Flow Activity Sludge Aeration Basins and Secondary Clarifiers.
  • UV Disinfection
  • Post Air Blowers
  • Discharge into Boise River

The Lander Street Facility has a seasonal Total Phosphorus limit of 1.0mg/L May-September that is met using enhanced biological phosphorus removal.  The facility produces high quality effluent that consistently meets effluent TSS, BOD, and Ammonia limits.

2:45pm - 3:00pmMonday Afternoon Break
3:00pm - 4:30pmSession 04C: Facility Operations
Location: 410ABC
3:00pm - 3:45pm

Development and Deployment of Gamified Simulation Software for Training Wastewater Operators - Cancelled

Keaton L Lesnik, Kimberly Grey

Maia Analytica, Portland, OR, USA;

As wastewater treatment has evolved, treatment operations have continued to become increasingly complex. At the same time, our understanding of the environmental, public health, and economic impacts of improperly treated wastes has grown, decreasing tolerance for disruptions. This means new operators are entering into an increasingly demanding environment in which they may not have much time to learn through trial and experience on the job. Additionally, operators are facing these challenges as the work is aging - stressing existing operator training norms. New methods for training operators are needed to help train the changing workforce. Process simulators are particularly well suited to illustrate the complex interrelationships inherent to advanced treatment systems that aren’t obvious or intuitive to new operators. Simulators allow operators to explore the consequences of operational decisions across the facility in an interactive, risk-free way. The emerging generation of operations professionals has shown an increasing affinity for hands-on, computer-based training and games provide an additional level of engagement and motivation that improves learning outcomes.

In this work we present a gamified simulator software called Wastewater Integrated Learning Management Activity (WILMA) designed to help operators learn the uniqueness of the system they will be operating, opposed to a generic treatment system. Engineers worked with partners at a full-scale facility to understand what is required to make informed decisions and analysis then designed mini-games around those decision points. Gamification of WILMA significantly improves engagement and motivation, both key pieces of improved learning outcomes. The game design and user interface is based on cognitive science research and state of the art visualization methods. Overall the presentation demonstrates and provides an example of training tools for the future of the wastewater workforce.

3:45pm - 4:30pm

Improving Operations at an Aging and Overloaded WWTP

Jack Wallis

Wallis Engineering;

As small communities grow, increases in wastewater loads can create outsized problems for their wastewater treatment plants. Over the last decade, the City of Stevenson wastewater treatment plant has seen dramatic increases in wastewater BOD and TSS loads and highly variable influent pH. This change in wastewater characteristics was driven by high strength users, including restaurants and beverage industries. Design for a major wastewater treatment plant upgrade began in 2019, but it would be some years before construction would be completed. In the meantime, the City would need to manage influent BOD loads that were higher than the existing treatment plant capacity, and avoid effluent violations.

To address these challenges, the design team identified improvements that could be implemented quickly to improve WWTP performance, while simultaneously designing the full plant upgrade. Multiple options were considered, including process control improvements, additional aeration, and clarifier modifications. Due to budget constraints, the City selected a low-cost option: adding DO sensors in the oxidation ditch, an influent wastewater pH sensor, additional RAS flow meters, and an improved SCADA system. These interim improvements are integrated with the 30-year old control system. Though they represented a “short-term” fix, they were designed to be integrated effectively into the control system upgrade to be constructed with the full plant upgrade. DOE allowed the City to use design funds to construct the interim improvements, a major budget benefit.

These interim improvements allowed operators to quickly respond to changing influent wastewater characteristics, and more effectively manage secondary clarifiers. In addition, influent pH data has allowed the operators insight into industrial discharges, allowing the City to educate the industrial users on when their discharges were impacting the treatment process, resulting in fewer pH spikes. Process control was improved dramatically at a very low cost, reducing the burden on operators during the interim period before a major treatment plant upgrade.

3:00pm - 5:15pmSession 01C: Alternate Delivery/Leadership/Wastewater - Livestream
Location: Room 400BC
3:00pm - 3:45pm

Transforming Design-Bid-Build to Improve Collaboration and Teamwork

Jason King, Michael Schulz

Keller Associates, Inc., United States of America;,

The design-bid-build procurement process can limit the chance for collaboration between the owner, engineer, and contractor. This drawback has been a driving force toward non-traditional delivery methods such as design-build, construction manager-at-risk, and progressive design-build. However, there are tools to improve collaboration, which can make the design-bid-build process remain the best option. Some of these tools include prequalifying contractors and providing a detailed construction constraint specification. The construction constraints section of bidding documents offers engineers a unique way to communicate challenging project aspects to contractors. When well thought out and detailed, construction constraints can help contractors understand anticipated shutdowns, required bypass pumping provisions, and limitations in the existing equipment’s operational capabilities.

Utilizing these and other tools to improve collaboration can also lead to an aggressive competitive bidding process. Recently, the City of Lewiston awarded a contract for the construction of wastewater treatment plant upgrades. The majority of their existing processes were being upgraded and expanded, which created an immensely complex project. Using collaborative tools, the contractors understood the project and had greater confidence in their costs, such that all bids were within ~5% on this $34M project. This presentation will introduce and discuss collaborative methods for improving the design-bid-build procurement process.

3:45pm - 4:30pm

Panel Discussion: Leadership Perspectives from the Future Workforce

Amy Dammarell1, Lara Kammereck2, Laurelei Mc Vey3, Kristi Steiner4, Andrew Matsumoto5, Jamie Eichenberger6, Lindsey Smoot7

1HDR, United States of America; 2Carollo; 3City of Meridian, Idaho; 4Jacobs Engineering Group; 5CivilWest Engineering Group; 6HDR; 7University of Idaho;,,,,,,

A diverse panel of active, local leaders with vast combined experience in water issues will share insight and their vision of the future workforce. In 2019, the Diversity and Leadership Track focused on leadership success and challenges associated with a diverse workforce from the point of view of those in the later stage of their career. In 2021, we will pose similar questions to a panel who are in the first half of their career looking forward. The panel will answer questions on their vision for future leadership based on tomorrow’s workforce, diversity and technology.

A panel of 5 will be developed with Conference Committee and Leadership Committee. Anticipate it will include diverse gender and age leaders at both private and public agencies from Washington, Oregon and Idaho.

4:30pm - 5:15pm

Screen Capture Efficiency Sampling & Testing Protocol for Waste Water Treatment Plant Screens at Start-up

James Impero

Ovivo USA, LLC, United States of America;

For approximately two decades, consulting engineers have asked screen manufacturers to provide third party, independent test results documenting the capture ratios of their screen’s debris removal efficiency. Have these results truly been reproducible at your wastewater plant?

Decades of third-party capture testing of screens in the UK have been a good thing. However, the screenings capture data proved only the “Capability” of that particular screen tested and under those specific UK flow conditions. Expecting identical capture results from the same manufacture’s screen at wastewater facilities with differing hydraulics, variable wastewater velocities, TSS & FOG loading characteristics, let alone up-front grinders is neither practical thinking or proven in the field to be true for 40%-45% of the current installation history in the US. Why? It is the very subject of this paper & conference presentation. There are definite wastewater similarities from site to site; however, there are also many dissimilarities that require screening equipment modifications to achieve the true screenings capture capability of any manufacturer’s screen. This presentation will discuss an inexpensive upstream and downstream on-site sampling method & procedure, as well as a protocol and accepted test methodology that can be performed at any municipal wastewater treatment facility or local third party laboratory to measure solids capture efficiency of any newly installed screen(s) at startup, including older screen installations that have fallen short of owner expectations.

This presentation will reveal standardized sampling hardware, process & procedure, as well as simple bench-top test method for determining the screenings capture of any headworks or membrane protection screen. A single day sampling method & protocol will be described in detail that will provide a screen’s site-specific debris capture efficiency. This standardized sampling and testing protocol can be performed by screen manufacturers, plant operators, and/or third party laboratory technicians.When incorporated into a consulting engineer’s screen specifications it will require all bidding manufacturers to meet a desired screen capture efficiency (±X%) in the bid spec. The awarded manufacturer will be responsible for meeting the specified screenings capture.

3:00pm - 5:15pmSession 02C: Stormwater - Livestream
Location: 120AB
3:00pm - 3:45pm

A Scalable Decision-Making Framework For Stormwater Retrofit Investments

Blair Scott1, Robin Kirschbaum2

1King County; 2Robin Kirschbaum Inc.;,

King County (County), WA, Stormwater Services Section (SWS) has identified the lack of stormwater controls in older developed areas as one of the most significant problems preventing recovery of the County’s streams, lakes, and Puget Sound. With approximately 150 square miles of untreated developed areas and population growth among the largest over the last decade of any county across the United States, the need to strategically plan and begin implementing stormwater management to control stormwater runoff and restore or prevent further degradation of aquatic health is considered urgent by King County and its regional planning partners.

SWS is working collaboratively with Robin Kirschbaum, Inc. (RKI) to develop clear goals and a strategic decision-making framework for identifying, prioritizing, and implementing stormwater management and engineering projects led or influenced by SWS that restore aquatic resources through improved stormwater controls. Building on existing County programs, policies, and initiatives, the project will not only focus on water quality and aquatic health, but on broader principles of critical importance, such as equity and social justice (ESJ) and climate change preparedness.

The decision-making framework will address subbasin prioritization and individual project identification, evaluation, and prioritization organized around the following multi-benefit outcomes:

  • Improve water quality outcomes
  • Increase resilience to climate change impacts
  • Preserve and restore wildlife habitat
  • Implement Environmental and Social Justice
  • Increase community stewardship
  • Accelerate or exceed regulatory requirements using stormwater retrofits

The decision-making framework will serve as a foundational pillar of the County’s 30-year plan for stormwater investments, currently being co-designed and co-implemented by a group of partners from across the region. The stormwater investment plan will rethink the region’s approach to addressing polluted runoff and prioritizing the needs of the residents impacted the most.

3:45pm - 4:30pm

A Greenhouse Evaluation of Stormwater Remediation Of Heavy Metals And PFAS By 10 Native Oregon Plants

Richard Hilliard, Bethany Parker, Jennifer Field, Tyler Radniecki

Oregon State University, United States of America;

Stormwater collects dissolved and particulate phase pollutants from improved surfaces and carries these to receiving water bodies, degrading their quality. Contaminants of particular concern include per- and polyfluoroalkyl substances (PFAS) and heavy metals such as copper and zinc. Infiltration systems of various designs are being implemented widely to provide passive treatment of these waters. Inclusion of plants in these systems provides potential for phytoremediation, prevention of erosion, increased soil porosity, and an aesthetic quality in the built environment.
Plants, along with associate microbes often vary greatly in their provision of degradation and removal of stormwater pollutants. In this study, 10 different native Oregon plants (n=6) including various monocots and dicots were investigated for potential treatment of copper, zinc, and PFASs (spiked-in) in surface runoff collected from a public works utility site in a 10-week greenhouse experiment. Aqueous, soil, and plant samples were analyzed using a combination HPLC-MS/MS and HPLC-QToF for PFAS and ICP-MS for heavy metals. Throughout the experiment, evapotransipration rates were monitored by weighing of the planted units. After the experiment, plant physiological qualities (masses and lengths of roots and shoots) were recorded. Enrichment of plant microbiomes in the rhizosphere and the bulk soil was evaluated by 16s rRNA amplicon sequencing to examine whether microbes are involved in stormwater phytoremediation.

Preliminary data suggest that some plants were much more effective at removing PFAS, particularly the shorter chain compounds. Additionally, some plants showed a net production compared to the control of PFPeS, PFBS, and PFHxS, suggesting the transformation of parent compounds FHxSA and FOSA.

4:30pm - 5:15pm

Emerging Technologies for Stormwater: A CMAC Pilot Project

Josh Van Wie1, Peter Holte2

1Osborn Consulting, Inc.; 2City of Redmond;,

Emerging technologies for stormwater are playing a crucial role in the Pacific Northwest to help municipalities meet their NPDES permit requirements and watershed management goals. Public agencies and their consultant teams must rely on innovation and collaboration to harness the latest technologies as permit requirements become more stringent and watershed management becomes more critical in urbanized areas.

During 2020-2021, the City of Redmond completed a pilot project to install Continuous Monitoring and Adaptive Control (CMAC) retrofits at two stormwater ponds. The CMAC system uses cloud software to optimize and control pond discharge flow rates through a remotely operated control valve. This technology was selected because of its potential to improve flow durations and protect downstream creek habitat in areas that were developed prior to current regulatory requirements for flow control.

To initiate the pilot project, Redmond identified four stormwater ponds as possible retrofit locations in the Monticello Creek watershed, which was previously selected as a priority watershed for the City’s 2013 Watershed Management Plan. A feasibility study was completed by Redmond’s consultant team, led by Osborn Consulting, to analyze the four ponds using the Western Washington Hydrology Model (WWHM) to assess potential improvements in flow durations at each pond after installing a CMAC retrofit. The modeling proved to be a valuable step in the process as some ponds showed significant potential improvements while the others showed little to no improvement due to site-specific hydraulic configurations or changes in basin hydrology that had occurred since the original design and construction.

Two ponds were selected to move forward with final design in late 2020 and construction of the CMAC retrofit installations in early 2021. The performance of the CMAC system will be monitored to determine its effectiveness and whether this technology has potential for more widespread use in helping the City meet its stormwater management goals.

3:00pm - 5:15pmSession 03C: Wastewater Process: Biological Intensification - Livestream
Location: Room 430AB
3:00pm - 3:45pm

CFD Modeling Provides Insights into Granular Sludge Separation Devices

Ed Wicklein1, Beate Wright1, Sudhir Murthy2, Charles Bott3, Bob Angelotti4, Haydee De Clippeleir5, Christine deBarbadillo5, Prarthana Pradhan1, Tanja Rauch-Williams1

1Carollo Engineers, United States of America; 2NEWhub; 3HRSD; 4UOSA; 5DC Water;

VIrtual Speakers

Granular activated sludge (GAS) consist of dense particles with stratified microbial colonies that provide efficient organics, nitrogen and phosphorus removal along with improving liquids/solids separation in activated sludge systems. GAS has gained broad interest and traction in recent years A growing number of water resource recovery facilities (WRRFs) in the U.S. and abroad have implemented inDense, a technology that uses hydrocyclones to select for GAS by separating it from lighter mixed liquor flocs. While hydrocyclones are an established approach to classify and separate particles in many fields, their application to GAS leaves key questions yet to be answered. Hydrocyclones have been designed, tested, and operated primarily based on empirical field performance data. To date, no group has successfully modeled GAS separation in AS systems by hydrocyclones despite the broad benefits this would bring to many WRRFs, until now. A team comprised of technical experts from equipment inventor, VA and DC utilities, and a consulting team collaborated on this effort to combine inDense installation and performance data from current full-scale inDense U.S. installations, state-of-the-industry understanding of GAS and inDense systems, and state-of-the-art CFD modeling capabilities. Project findings will be presented, illustrating that CFD modeling developed in this project simulating hydrocyclone GAS separation is a useful tool to inform the design and operation of external selector systems. This will lead to clear visualization of internal separation process, expanding our understating of how to adjust operations to different process and seasonal conditions.

3:45pm - 4:30pm

Experience With Densified Mixed Liquor And Nutrient Removal At Two WWTFs In Washington

Eric Smith, Tom Coleman

RH2 Engineering, Inc, United States of America;,

The Cashmere and Peshastin WWTFs discharge to the Wenatchee River, which has a TMDL for phosphorus. The Cashmere WWTF was the subject of the article “Cashmere Quality – Experience with enhanced biological phosphorus removal, surface wasting, and aerobic granular sludge” which appeared in the July 2020 edition of the Water Environment and Technology magazine. This presentation will expand upon that article and share recent findings related to the densified mixed liquor and biological nutrient removal at both WWTFs.

The Cashmere WWTF is a plug flow modified Bardenpho process and the Peshastin WWTF is a sequencing batch reactor. The two WWTFs have significantly different influent characteristics. Cashmere has a moderate strength influent due to a large apple slicing facility that discharges to the City’s system. Peshastin has relatively weak wastewater as the community is served by a septic tank effluent system, which removes settleable solids prior to discharge to the WWTF. Additionally, the Peshastin WWTF receives widely varying flows throughout the year from two fresh fruit packing warehouses that discharge significant quantities of rinse water to the system.

Each WWTF is configured to favor biomass with good settling characteristics. Both plants exhibit significant fractions of aerobic granules as part of the biomass and each process achieves exceptional settling at relatively high mixed liquor concentrations. For instance, the Cashmere WWTF routinely has mixed liquor suspend solids concentrations in excess of 6,000 mg/L with SVIs below 50, in conjunction with a clarifier blanket below 2 feet.

The capacity of a WWTF is generally proportional to the mass of mixed liquor suspended solids that can be carried within the system. The settleability of these solids is a critical parameter as it can significantly affect the footprint necessary to support the process. Implementing bacterial selection processes through WWTF design and process controls can change the structure and function of the microbial communities to provide a densified mixed liquor, as can be found at the Cashmere and Peshastin WWTFs. Insights into these two WWTFs may be useful to other plants needing to increase treatment capacity relative to plant footprint while achieving biological nutrient removal.

4:30pm - 5:15pm

Advanced Aeration Control with Densification Achieves BNR Intensification: A Full-scale Demonstration of the Ntensify Process

Pusker Regmi, Jose Jimenez

Brown and Caldwell, United States of America;

VIrtual Speakers

Driven by stringent new nutrient standards and increasing costs of nutrient removal, utilities in the Pacific Northwest must look towards innovative approaches to solve the issue. Advanced aeration controls like ammonia vs NOx (AvN) or ammonia-based aeration control, lower the aeration energy while promoting a more carbon-efficient nitrogen removal via simultaneous nitrification and denitrification (SND). Low dissolved oxygen (DO) maintained by advanced aeration control is the key to aeration savings and SND but often leads to poor settling sludge. The Ntensify approach combines low DO operation with hydrocyclone based wasting to achieve continuous flow aerobic granulation and enhanced nutrient removal. This presentation will describe the results from the full-scale Ntensify installation at the James R. Dolorio Water Reclamation Facility (JRD WRF) in Pueblo, Colorado.

The JRD WRF is a 19 mgd biological nutrient removal (BNR) facility that operates a Johannesburg process. The recently upgraded facility includes hydrocyclones that feed a portion of the RAS to target lighter organism waste in the mixed liquor. Upgrades implemented AvN control, allowing DO setpoints to fluctuate between 0.2 – 2 mg/L while maintaining equal effluent ammonia and NOx concentrations.

Improvement results showed that hydrocyclone-based wasting helped improve settling characteristics [sludge volume index (SVI) < 100 mL/g values ranging from 130 to 300 mL/g before implementation] within weeks of operation. Phosphorus accumulating organisms (PAO) and nitrifiers are preferentially retained in dense flocs and granules, while lighter heterotrophic and filament-type organisms are preferentially wasted. The hybrid floc-granules combination at Pueblo achieved excellent effluent turbidity (effluent TSS < 6 mg/L, turbidity < 2 NTU). AvN control resulted in low DO conditions (< 0.4 mg/L) that reduced air demands by 50% while supporting excellent nitrogen [effluent total inorganic nitrogen < 11 mg/L] and total phosphorus (TP) removal (effluent TP < 1 mg/L)] at low influent carbon conditions (primary effluent COD/N <6) without supplemental chemicals.

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.

3:00pm - 5:15pmSession 06C: Wastewater Process
Location: Room 130
3:00pm - 3:45pm

Meeting Stringent Ammonia and Disinfection Byproduct Limits with Preformed Monochloramines

Jennifer Chang1, Rachel Golda2, Peter Schauer2, Larry Schimmoller1, Matt Noesen1

1Jacobs, United States of America; 2Clean Water Services, Oregon;,

The Rock Creek Advanced Wastewater Treatment Facility (RCAWWTF) must balance low effluent ammonia limits, disinfection requirements, and potential low disinfection byproduct (DBP) limits.

The ammonia and disinfection limits are currently met through stable nitrification and use of sodium hypochlorite (SHC) disinfection, respectively. Effluent characterization identified the presence of two trihalomethane DBPs of potential regulatory interest when effluent ammonia concentrations were low: bromodichloromethane (BDCM) and chlorodibromomethane (CDBM). Initial estimates suggest that future discharge limits for CDBM and BDCM may be as low as 1.1 µg/L and 1.5 µg/L, respectively.

Preformed monochloramine (PFM) disinfection was identified as an operational strategy for reducing DBP production. This method utilizes monochloramines that are formed by mixing ammonia and sodium hypochlorite in carrier water before mixing with process water, greatly reducing the opportunity for DBP formation. Bench-scale testing followed by pilot testing was conducted to determine if utilizing a PFM disinfection approach could be an effective solution.

Preliminary bench-scale testing of insitu monochloramines (ISM) versus PFM indicated that PFM was a promising option to meet the disinfection and DBP formation goals; therefore, pilot-scale testing was pursued.

A flow-through pilot system was constructed at the RCAWWTF to receive tertiary effluent where a PFM solution could be added. Testing evaluated:

  • Effects of varying PFM dose at a constant chlorine-to-ammonia ratio of 4:1, and
  • Effects of varying chlorine-to-ammonia ratio.

Testing demonstrated the benefits of using PFM over free chlorine and ISM by meeting disinfection permit limits and significantly reducing DBP formation potential while still maintaining effluent ammonia concentrations that met permit limits. These results show the viability of implementing PFM disinfection as a solution to more stringent DBP limits. Other clean water utilities may benefit from modifying existing chlorine disinfection to PFM disinfection as a much more cost-effective alternative relative to converting to another disinfection technology.

3:45pm - 4:30pm

BNR Conversion of the Oro Loma/Castro Valley Water Pollution Control Plant

David Seymour

Kennedy Jenks, United States of America;

Virtual Speakers

Maintaining reliability in aging infrastructure has become a significant investment for wastewater agencies as facilities approach the end of their useful life. One such agency, Oro Loma Sanitary District (OLSD), was faced with a significant investment to rehabilitate a 7-mile long 189 MGD deep-water outfall in San Francisco Bay shared by six agencies. At the same time, nutrient regulation was being considered through a region-wide watershed permit that would require higher levels of treatment at OLSD’s 20 MGD Water Pollution Control Plant (WPCP). OLSD identified a project that would address these two challenges.

Implementation of $26M biological nutrient removal (BNR) upgrade of the existing secondary treatment process allowed OLSD to cost-effectively comply with anticipated regulation in the future watershed permit for nitrogen removal. In addition, an improved effluent quality allowed OLSD to renegotiate its NPDES permit to allow for the use of a near-shore outfall during wet-weather as an alternative discharge location to the deep-water outfall. Permitted use of the alternative outfall allowed OLSD’s partner agencies additional capacity in the shared deep-water outfall, as well as reducing OLSD’s liabilities for future outfall maintenance. The BNR upgrades were designed and constructed over a 3-year period and went into operation in September 2020.

This presentation will highlight how BNR was incorporated into the WPCP, the anticipated benefits of the project, and how the improvements are performing based on the first months of operation.

4:30pm - 5:15pm

Primary Sludge Fermentation: A Wretched Hive of Scum and Villainy

Rachel Golda, Adrienne Menniti, Peter Schauer

Clean Water Services, United States of America;

The Unified Fermentation and Thickening (UFAT) process is used at two Clean Water Services (CWS) Resource Recovery Facilities (Rock Creek and Durham) for primary sludge fermentation, generating volatile fatty acids (VFA) to support biological phosphorus removal. The Durham plant has a problem with fermenter scum buildup, forming dense mats during warm periods; a problem not shared by the Rock Creek fermentation system. The goal of this project was to inform design decisions on an upcoming fermenter expansion at the Durham plant by clarifying the role played in scum mat formation by three significant design differences between the facilities: 1) sludge heating, 2) sludge screening, and 3) scum removal.

Laboratory experiments using heated primary sludge reactors showed a correlation between scum mat formation and temperature, with mats forming more quickly with increasing heat. Observations of gas bubbles caught in and under scum mats in the laboratory and at full-scale suggest that solids from the sludge blanket may be floated to the surface of the fermenter by biologically-generated gas during fermentation. Laboratory experiments also showed that unscreened primary sludge produced scum mats more quickly than screened sludge, and that these mats persisted longer. Unscreened Durham primary sludge contains irregular, thread-like solids like hair and fibers. We observed these in dense formations in the full-scale mat, suggesting that they provide a structural matrix for scum to congeal to, trapping gas bubbles.

Our observations suggest that gas production from fermentation activity causes solids from the sludge blanket to rise to the surface, creating or exacerbating scum mats. The fermentation process is accelerated at warm temperatures, which is likely why mat formation worsens during warm periods. Screenable solids also likely play a substantial role in providing a stabilizing network for scum solids to adhere to, worsening scum problems at plants that do not utilize primary sludge screens. Installation of capital improvements such as sludge screens and scum handling systems are multi-million dollar investments; this work offers valuable insight into the roles played by fermenter design differences in mitigating scum accumulation and can inform design decisions regarding installation or improvement of UFAT fermentation systems.

4:30pm - 5:45pmWomen’s Networking Reception
Location: The Grove Plaza
5:00pm - 7:00pmExhibitors Opening Reception
Location: Exhibit Hall
7:00pm - 8:00pmDinner—Monday Night Dinner
Location: Room 400A
7:00pm - 10:00pmNetworking Night
Location: The Grove Plaza

New this year – PNCWA is excited to host a Monday Night Networking evening in lieu of separately hosted consultant events. This will serve as a chance for all PNCWA members and attendees to get together and celebrate being together after the last year and a half and build excitement for the future. The combined event will be open to all conference attendees, creating an open and inclusive event that aligns with our vision as an organization.  

Through this event, we’ll be extending Monday Night Football beyond the exhibit hall floor! Join us outside on the Grove Plaza for the networking event of the evening! We will have screens available for viewing the game, light appetizers, and tons of networking. Each attendee will receive 1 complimentary drink ticket from PNCWA to use at the beverage tent. We are looking forward to bringing everyone together after a challenging year.