Conference Agenda

Per- and Poly-Fluoroalkyl Substances (PFAS) are a large family of organic compounds, including more than 4,500 synthetic fluorinated organic chemicals used in commercial, consumer and industrial products since the 1940s. Conventional sewage treatment methods do not efficiently remove PFAS which are resilient to degradation and tend to sequester to the treated solids produced and the resultant biosolids. In its most recent (2021) review of pollutants in biosolids, the US EPA identified eight PFAS in biosolids, and is undergoing a problem formulation process which will serve as the basis for determining whether regulation of PFOA and PFOS in biosolids is appropriate. If EPA determines that a regulation is appropriate (currently expected in 2024), biosolids producers will be required to meet certain standards. This potential outcome of EPA’s review underscores the importance of understanding technical solutions available to treat PFAS in biosolids if required based on EPA’s review process.

To assist utilities and biosolids producers understand options available to mitigate potential PFAS contamination in biosolids, Jacobs has tested several biosolids products including dried biosolids, pyrolyzed dried biosolids and composts, all produced with non-industrially impacted biosolids to assess the concentration of PFAS compounds in the finished products and the ability of these processes to reduce and or remove PFAS compounds. Samples of input and output solids, bulking agents and finished products were analyzed for 24 PFAS compounds utilizing Liquid Chromatography Tandem Mass Spectrometry (LC/MS/MS). Data will be presented on three dried biosolids facilities, two pyrolyzed dried products including output solids, gas and oil, and six compost products.

This presentation will provide information regarding the measured concentrations of PFAS in wastewater solids, dried biosolids, pyrolyzed biosolids and biosolids based compost products. PFAS precursor analyte presence and concentrations in the input solids as well as the wastewater treatment process used to generate these products will also be presented. This information will be useful for those considering methods to reduce or eliminate PFAS in their own wastewater solids or other input wastewater solids at existing or planned biosolids management operations to ensure the lowest feasible PFAS concentrations in end products can be achieved.

Federal and state regulatory agencies—and the public—have growing concerns about public health and environmental wellbeing associated with per- and polyfluoroalkyl substances (PFAS). As of this writing, the United States does not yet have federally enforceable PFAS standards for drinking water, wastewater, or biosolids. This has left states to develop their own regulations to address PFAS contamination, creating a diverse regulatory patchwork across the country. State regulations on PFAS in drinking water are becoming common, but now a few states are also enacting regulations on PFAS in surface water and biosolids as well. For example, Michigan has developed screening levels for PFAS in biosolids, and Maine has effectively banned biosolids land application due to concerns about PFAS.

The EPA plans to complete a risk assessment for two PFAS [perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS)] in biosolids for land application by Winter 2024. PFOS is commonly detected in biosolids at a concentration around 10 ppb, even without any industrial sources. A biosolids PFOS limit below that level could widely restrict land application, having a large impact on our industry. This risk assessment requires knowing many parameters for PFAS toxicity, occurrence, fate, and transport. This presentation will walk through the risk assessment process, what parameters are known, and which are not, along with proven methods utilities can use to keep stakeholders and customers informed.

Elected officials, stakeholders and the public are interested in actions utilities are taking to protect public health and the environment. Having a response plan in place to monitor, assess and respond to emerging regulations can “calm the waters” while the regulatory process unfolds. One topic of interest is how to treat PFOS. Ongoing research on PFAS-destroying technologies includes investigations into incineration, pyrolysis, gasification, supercritical water oxidation (SCWO), hydrothermal liquefaction, and hydrothermal alkaline treatment. This presentation will compare the latest known PFAS destruction efficiencies, market readiness, and other considerations that impact the feasibility of these technologies for widespread use. A regulatory update on proposed legislation in the Pacific Northwest will also be provided.

“Forever Chemicals,” parts per trillion, Health Action Levels, “over 5,000 chemicals,” “found in everyday products”—these phrases are common in articles and communications about PFAS to the public. To the general public, they are hard to put into context. They can be confusing, if not frightening, leading to lots of questions that are hard to answer. With the technical nature of PFAS removal and the developing research about PFAS health impacts, providing clear concise information to the public is challenging.

Meanwhile the water and wastewater industries are working hard to reduce the amounts of PFAS in drinking water, treated wastewater, and biosolids; doing research to know more about risks; and developing and testing new technologies for PFAS removal. It is increasingly critical for the public to understand risks and the steps that their utilities are taking to work on this issue.

There is a strong need for clear, timely, and proactive communication on PFAS removal. Public awareness can build support and the understanding water utilities will need to invest in and implement programs to address PFAS and other future challenges.

Becca Fong and Rachel Garrett will show how using best communications practices creates an increased level of engagement and an understanding of PFAS risk in wastewater and biosolids. They will present examples of how to integrate strategic engagement early in the process, how to work with technical teams to support the development of sound messaging and provide examples of how stakeholder engagement and community outreach work together to create clear, accurate, and timely risk communications for positive outcomes.

PFAS are a contaminant of major concern for WRRFs due to current and imminent state and federal regulations as well as increasing concern from the public. Because WRRFs are not designed to destroy or remove PFAS, source control will be an extremely important mechanism for reducing PFAS concentrations at WRRFs. For effective source control, an understanding of the dominant sources of PFAS to the WRRF is critical. However, PFAS are frequently detected in domestic, commercial, and industrial wastewater discharges with varying concentrations and are complicated by the presence of ‘precursors’ and PFAS-like compounds. A method is needed for identifying and addressing the site-specific dominant sources of PFAS to a WRRF.

While some states have propagated regulations to land-application of biosolids due to PFAS concerns, little is known about the fate of PFAS in land-applied biosolids, and even less is known about the fate of PFAS in land-applied reuse water. To protect the environment as well as protect beneficial biosolids and reuse applications, a better understanding of the fate of PFAS is needed in soils, groundwater, and surface waters.

Since 2019, Clean Water Services (CWS) has been conducting regular PFAS monitoring at the WRRFs, the collection system, and industries. Some of the results of this study were presented at PNCWA in 2022. Since that time, CWS has expanded the monitoring to include soils at biosolids and reuse land-application sites, groundwater at reuse irrigation sites, surface waters around the watershed, and more industries. CWS also has been collecting PFAS data from sewersheds dominated by a single land-use to help identify the dominant sources of PFAS to the WRRFs. Throughout the monitoring, CWS has been working with industries with high measured PFAS and/or high flows to develop PFAS Management Plans. Much has been learned about the contribution of WRRF discharges to the PFAS burden in surface waters, the fate of PFAS in land-applied reuse and biosolids, the dominant sources of PFAS to the WRRFs, and the effectiveness of outreach efforts. This talk will report the findings of these efforts since last year, lessons learned, and our PFAS roadmap for the next three years.

Clean Water Services (CWS) operates three water resource recovery facilities (WRRFs) that are subject to thermal load and daily maximum 1-hour average effluent temperature limits under their watershed-based NPDES permit. Current compliance strategies include water quality trading, flow augmentation, wetlands treatment, and riparian shade and recycled water programs. The recent discovery of the invasive emerald ash borer is expected to decimate the population of Oregon ash trees, a major riparian shade species. To expand their temperature management portfolio and compliment these “outside the fence” strategies, CWS is conducting studies to better understand temperature dynamics in WRRFs and explore potential “inside the fence” mitigation strategies.

Several models have been published that account for the major heat gains and losses from the activated sludge process. These models were reviewed and adapted into a spreadsheet that allows the temperature dynamics of each unit process in the WRRF to be modeled. The model was calibrated to three months of data collected at the Durham WRRF.

The calibrated Durham temperature model shed light on the relative contribution of each unit process to the overall thermal balance of the WRRF and was used to identify the most significant heat sources and losses in each. The aeration basins were the largest contributors to increased effluent temperature. The secondary and tertiary clarifiers gained heat during the day and lost it overnight. In contrast, the covered primary clarifiers largely followed the influent temperature with less extreme daily temperatures.

Basin shading was explored as a potential peak hour effluent temperature mitigation strategy. First, solar radiation was reduced by 90% in the model, which suggested peak hour temperature reductions > 0.5°C were possible. Second, a two-month pilot study was conducted at the Rock Creek WRRF. Two basins were evaluated side-by-side. One was left uncovered while the other was covered with a shade cloth with a 90% UV reduction rating. The peak effluent temperature from the shaded basin was lower than the unshaded basin by 0.2°C on average.

This presentation highlights the insight gained from temperature modeling in WRRFs and highlights basin shading as a promising low-capital, low-energy temperature mitigation strategy.

Clean water agencies, regulatory agencies, and watershed stakeholders are searching for innovative approaches and best practices to address water quality challenges due to nutrient enrichment and a changing climate. Through a series of interactive workshops in three different geographic regions, this Water Research Foundation project developed a framework to advance nutrient management that fosters innovation and new opportunities. The project goal is to focus on approaches that may be applied nationally and tailored to address unique water quality improvement needs and varying watershed contributions from point and nonpoint sources.

The culmination of Water Research Foundation Project No. 4974 is a new framework to improve holistic watershed nutrient management through Practices, Policies, and Partnerships. "Practices" refers to the technical considerations related to nutrient removal wastewater treatment, best management practices for nonpoint sources such as stormwater and agricultural land uses, and nutrient processing and impacts on receiving water environments and the atmosphere. "Policies" refers to the regulatory, institutional, and administrative aspects that govern nutrient management. This includes nutrient discharge permitting and compliance with receiving water quality standards, as well as watershed management requirements. "Partnerships" refers to the potential for collaboration, building relationships and trust, and leadership in nutrient watershed management. This includes consideration of diverse stakeholders with varied interests that may, or may not, be aligned.

This nutrient management framework provides a structured process with key success factors that can be tailored to develop holistic watershed-based nutrient reduction plans. Balanced nutrient reduction plans that integrate practices, policies, and partnerships should yield more effective and efficient implementation focused on consensus-based outcomes that provide greater net environmental benefits. The framework also provides a diagnostic lens to identify missing elements of existing nutrient reduction efforts that have not achieved planned outcomes.

Impacts of climate change and environmental justice (EJ) challenges were overarching themes that are addressed through this framework and within each element. Climate change complicates water resources management in multiple ways, from extreme weather events to potentially more significant responses to waterbody nutrient inputs (e.g., harmful algal blooms). The overarching issue of EJ spans all three nutrient management factors (practices, policies, and partnerships).

We all recognize that water is essential to human and environmental health. During our training we master the scientific and technical subjects, but seldom integrate the study of the people impacted by environmental challenges and the technical solutions we design. To promote diversity, equity and inclusion (DE&I) we should look beyond our workplace and try to represent with our workforce the communities we serve, to increase the visibility of the critical role of our profession and to uphold the professional canon of holding paramount the welfare of the public.

With this presentation I will share observations about the human component in various water-energy projects, to promote discussion and learn your point of view.

This presentation will provide an overview of social value and environmental justice in the context of our water industry, followed by examples of how the three pillars have been implemented on both a national and local level.

The world of wastewater treatment can be intimidating at first – it’s so much more complicated than it seems from the outside. If you’re new to wastewater and working at a wastewater or water reclamation facility you are probably familiar with the treatment that your facility does. But what about all the other facilities? Are they all using the same system that you know (and love)? Probably not, each facility is a little different so that they can efficiently and successfully treat the influent they receive. This talk will discuss some basic types of treatment systems so that you can breakdown and categorize a new, unfamiliar facility.

Using examples of facilities here in the Pacific Northwest, we’ll cover some of the common wastewater treatment systems, including the Activated Sludge Process (ASP), Membrane Bioreactors (MBR), Moving Bio Bed Reactor (MBBR), and Lagoon Treatment. The components of each treatment type will be described so that you can easily identity a system. Then the different systems will be compared in terms of cost, flow capacity, energy use, footprint size, and nutrient removal. This will allow you to not only identify a facility type but understand why that system was selected. Learning about different treatment systems is a great way to ease into wastewater (not literally) and to understand which technologies could be added to your facility efficiently and economically.

Clean Water Services is onboarding several methods to quantify viral removal, deactivation, and disinfection through our wastewater treatment facilities. Coliphages are viruses specific to E. coli that are commonly used as surrogates for human pathogenic viruses due to their similar fate and transport through wastewater treatment facilities as well as in the ambient environment. The US EPA is continuing the process of developing coliphage as fecal indicators for recreational water quality criteria. Coliphages are thought to be equal to the EPA’s currently recommended bacterial indicators when detecting fecal contamination, while providing more direct indicators of viral abundance in treated wastewater than bacterial methods. The current EPA method for quantifying coliphage is laborious and time-consuming, with sample processing requiring several days from starting preparation until final data becomes available. Optimized molecular methods are far faster and higher throughput, greatly reducing staff time required for monitoring and reducing time for data delivery from a scale of days to hours.

The goals of this project were to (1) onboard the EPA method for quantifying coliphage (EPA 1643, culture-based plaque assay) in our Water Quality Laboratory, (2) develop a multiplex droplet digital PCR-based molecular method to quantify coliphage based on published quantitative PCR methods, and (3) identify an optimal viral concentration method to aid in quantifying viruses in dilute samples (e.g., plant effluent). We will share our data on different viral concentration methods to prepare plant effluent for molecular analysis, and describe the influence that the initial viral concentration method may have on final viral quantification. The plaque assay and molecular methods will be used through the spring and summer of this year for influent and effluent characterization.

This presentation will detail the process of onboarding two different viral detection methods: the plaque assay and the molecular method, and a comparison of the data. This work is anticipated to be of interest to facilities looking toward viral detection methods in anticipation of future regulatory limits.

Conventional design and operation of enhanced biological phosphorus removal (EBPR) focuses on providing volatile fatty acids (VFAs) from the collection system and sometimes from primary sludge fermentation to phosphate accumulating organisms (PAOs) in an influent anaerobic zone. Alternately, sidestream EBPR (S2EBPR) diverts a portion of the RAS to a longer hydraulic retention time (HRT) sidestream reactor where biomass and particulate COD is fermented endogenously to generate the VFAs required. Successful S2EBPR operation hinges on the sidestream zone producing enough VFA to support healthy PAO populations in the HRT available.

Clean Water Services incorporated S2EBPR into a recent secondary expansion but did not observe the process to improve EBPR stability over conventional EBPR operation. In order to investigate possible reasons, the apparent fermentation rate (AFR) at three CWS facilities was measured. The results showed that there is variably in the AFR across time and season in the same facility, between different facilities and based on the method used. The CWS testing also highlighted an integral parameter used to estimate the AFR from batch testing results: the ratio of VFA removed to orthophosphate released (the P-release ratio). Long term measurements of the P-release ratio show that it is also highly variable over time.

Polyhydroxyalkanoate (PHA) measurements were also performed during the bench scale AFR testing and during full scale S2EBPR operation. The goal is to determine if shifts in carbon storage may impact S2EBPR process performance. The results indicate strong differences in the type of PHA stored between conventional EBPR and S2EBPR. The possible reasons for this shift will be explored but it is as yet uncertain how carbon storage changes relate to differences in process performance.

This presentation will provide an overview of how apparent fermentation rate testing fits into design and operational decision making and will discuss the overall methodology and approach. CWS results will be compared against original design assumptions and against wider industry results. The importance of the P-release ratio and possible sources of variability over time will also be summarized.

A major interceptor with 7MGD flow in Pierce County’s Chambers Creek Water Resource Recovery Facility (CCWRRF) collection system has historically been plagued by microbially induced corrosion (MIC) and odor problems, with gas phase hydrogen sulfide concentrations as high as 200ppm. The rate of concrete corrosion as measured by weight loss was 8-9 % annually based on a concrete coupon study.

The CCWRRF was expanded to provide biological nutrient removal in anticipation of nitrogen nutrient limit from the state, which in turn led to the requirement for industrial users to reduce nitrogen nutrient loadings. A wastewater characterization study revealed that an industrial user discharges a high-strength waste stream with an ammonia concentration as high as 2000 ppm and is a major contributor of ammonia loading to the interceptor. Armed with the knowledge that nitrate compound addition is one of the best solutions to control MIC, CCWRRF decided on a creative approach for nutrient removal by this industry. Instead of complete nitrogen nutrient removal through the full cycle of nitrification and denitrification, the industry is asked to nitrify only, generating a waste stream with nitrate concentration as high as 2000ppm which is discharged to the collection system. This strategy has been proven to be very successful and is mutually beneficial to CCWRRF and the industrial user: MIC and odor in this interceptor have largely been controlled, as evidenced by liquid phase sulfide concentration at less than 0.2ppm and gas phase hydrogen sulfide reduction by 90%, without incurring the significant cost of nitrate salt addition by CCWRRF; and the industrial user achieved significant costing savings by not having to add supplemental organic carbon to achieve denitrification.

EPA promulgated aluminum aquatic life criteria in 2021 for Oregon based on the 2018 nationally recommended criteria. Aluminum is traditionally measured in environmental samples as total and dissolved aluminum, and criteria were based on total aluminum. However, the method to measure total aluminum uses a very low pH digestion which aggressively dissolves aluminum bound in clays and other mineral forms. This overestimates the amount of aluminum that is bioavailable and potentially toxic to aquatic life. Using total aluminum would assess more water bodies as impaired than would be accurate, and the listing could require TMDLs to be developed. For NPDES permittees using alum, this could result in unnecessarily restrictive aluminum limits which may impact the ability of WRRFs to use alum to meet phosphorus limits. Therefore, in implementation efforts, EPA recognized a new analytical method (Rodriguez et al. 2019) that measures bioavailable aluminum and allowed its use for river measurements.

Clean Water Services (CWS) is committed to studying analytical methods that best measure the potential toxicity of aluminum. The CWS Water Quality Lab began using the bioavailable aluminum method in 2019 and analyzed total, bioavailable, and dissolved aluminum in concurrent effluent and river samples from the Tualatin River. Results consistently show that a low fraction of the total aluminum is bioavailable to aquatic life in the Tualatin River, with an average of 7% bioavailable. Bioavailable aluminum concentrations were always less than the instantaneous water quality criteria calculated from the water quality standard, while 50% of total aluminum concentrations were greater than the criteria. Data also demonstrated that aluminum from CWS WRRFs that use alum is almost entirely bioavailable, highlighting the importance of reducing tertiary alum and the implementation of alternative methods of phosphorus removal. CWS has collaborated with Oregon DEQ to monitor total, dissolved and bioavailable aluminum in a broader range of rivers. CWS plans to continue bioavailable aluminum monitoring efforts and collaboration with Oregon DEQ in support of this method. ASTM publication, as well as 40 CFR approval, are important next steps in wider acceptance of the method by EPA in future aluminum criteria updates.