Blate, Micah

Micah is a senior associate with Hazen, located in Philadelphia, and specializes in wastewater process optimization, modeling, and facility design, helping utilities enhance treatment performance and reliability. His expertise includes nutrient removal strategies, whole-plant process modeling, and process upset support. With hands-on experience in lab, bench-scale, and full-scale piloting, he is also a PhD candidate researching microbial PFAS degradation.

Titles from this speaker

Description: A New Biosolids Management Trend is Emerging: Biochar Producing Technologies are...

A New Biosolids Management Trend is Emerging: Biochar Producing Technologies are Rising to the Top, Wonder Why?

Abstract

The mounting pressure on land application of biosolids coupled with rising costs of processing, hauling and beneficial use is becoming a burden on utilities. The presence of PFAS and potential regulations for practicing land application require considering emerging technologies with PFAS reduction capabilities. Pyrolysis and gasification are emerging technologies that are gaining interest for biosolids management and in most cases, they are the top alternatives for consideration. This trend is mainly due to significant reduction in mass and volume, thus significant reduction in beneficial use costs making the overall economics favorable when compared to conventional technologies. Pyrolysis and gasification produce biochar that has no detectable PFAS, protecting utilities from any future regulation for biosolids land application. Finally, biochar is considered a carbon sink due to carbon sequestration, thus reducing overall greenhouse gas emissions. This paper presents the results from various evaluations for different utility sizes and geography.

This paper presents results from various biosolids management studies for facilities with different sizes and geography. Emerging technologies that convert biosolids to biochar, such as gasification or pyrolysis, are rising to the top, mainly due to reducing overall cost, ability to beneficially use biochar with non-detect PFAS and finally greenhouse gas emission reduction.

SpeakerAbu-Orf, Mohammad

Presentation time

14:00:00

14:25:00

Session time

13:30:00

15:00:00

SessionUnderstanding and Addressing PFAS in Biosolids

Session locationRoom N426b - Level 4

TopicMunicipal Wastewater Treatment Design, PFAS

Author(s)

Abu-Orf, Mohammed, Blate, Micah, Dursun, Derya, Knowles, Paul, Abu-Orf, Mohammed

Author(s)M. Abu-Orf 1; M. Blate 1 ; D. Dursun 2; P. Knowles 3; M. Abu-Orf 1;

Author affiliation(s)Hazen and Sawyer, New York, NY 1; Hazen and Sawyer, New York, NY 1 ; Hazen and Sawyer, New York, NY 2; Hazen and Sawyer, New York, NY 3; Hazen and Sawyer, New York, NY 1;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825159012

Volume / Issue

Content sourceWEFTEC

Word count18

Biosolids Solutions Tailored to Fit Small Facilities

Abstract

Introduction Rising disposal costs, flexibility in biosolids beneficial reuse end use, the desire to optimize bioenergy use, and the uncertainty around future regulations require utilities to balance proactivity with their inevitably constrained capital budgets. This presentation will review two customized planning solutions developed for smaller utilities (2 million gallons per day (mgd) and 12.6 mgd), helping them prepare for future changes without committing to large-scale capital expenditures prematurely. Case Study 1: Opequon Biosolids and Bioenergy Planning The Opequon Water Reclamation Facility (OWRF), located in Winchester, VA, is permitted to treat 12.6 mgd. The OWRF uses mesophilic anaerobic digestion (MAD) and dewatering to produce Class B cake for beneficial use. The OWRF accepts fats, oils, and grease (FOG) and high strength waste (HSW) from industrial customers for co-digestion. The OWRF generates electricity using digester gas in a combined heat and power (CHP) system. While co-digestion increases digester gas production available for beneficial use, it is believed to also reduce dryness of final cake product, increasing hauling and management costs. A biosolids and bioenergy evaluation was conducted for Frederick-Winchester Service Authority (FWSA), the owner/operator, and included the following considerations: 1.Digester gas production in excess of what can be beneficially used in the current CHP, 2.Existing CHP reaching the end of its expected useful life, 3.Significant increases in biosolids hauling and management costs from the third party contractor, exacerbated by the low percent total solids in the final cake product due to industrial flows 4.Potential for future regulations on emerging constituents of concern in biosolids, including PFAS and microplastics Approach Alternatives Development A world-of-options list of biosolids management and digester gas beneficial use technologies was developed. The list was narrowed down through a multi-criteria, non-cost evaluation that scored the technologies against the OWRF's weighted objectives: market sensitivity, future flexibility, ease of operations and maintenance, environmental impact, and community impacts. A short list of alternatives was identified for evaluation in the next phase, which included development of an energy balance and financial analysis evaluation. The alternatives to be considered were combinations of the following: - Baseline solids management: continue MAD and production of Class B cake - Baseline gas management: replacement in kind of the CHP system - Advanced thermal processing (drying with pyrolysis or gasification) - Supercritical water oxidation - Upsizing the CHP system Vendor outreach was conducted to understand the sizing options commercially available as well as estimated capital and O&M costs and site-specific implementation considerations. Operating, maintenance and plant design data was used to conduct preliminary sizing of potential alternatives and in completing a 20-year net present value lifecycle cost evaluation. Energy Balance and Financial Analysis Using the Power BI-based Energy Balance Analysis Tool (EBAT), a framework was developed to provide a sensitivity analysis of the short-listed alternatives against the input parameters. Mass and energy balances were completed to determine the likely energy use/generation potential. Comprehensive 20-year lifecycle costs of each combination of biosolids and bioenergy alternatives were calculated including O&M costs, financing costs for demolition and construction, biosolids disposal costs, and any bioenergy-recovery benefits, such as energy savings and/or revenues. FWSA benefits from analysis using EBAT because they can adjust inputs and variables to simulate how future conditions may evolve. For example, by reducing the capital costs (anticipated as technology matures) or increasing Class B hauling costs (as regulations evolve), the most cost-effective alternative changes. Results Figure 1 shows part of the EBAT dashboard, illustrating the user functionality and visualizations. The tool makes it very easy to prepare projections and conduct justifiable decision-making for stakeholders. Figure 2 shows the 20-year net present value of each combination of alternatives. Two different sizing options for advanced thermal processing were considered to explore if a piloting approach would make financial sense for the OWRF. Nominal decrease in 20-year net present cost was predicted with a pilot demonstration of an advanced thermal process over a full-scale; this approach could be considered to further explore viability of the technology. The results of the evaluation suggest that at current market and regulatory conditions, the most cost-effective option is to continue digestion and replace the CHP in kind, due to the marginal estimated benefit of upsizing the CHP. The OWRF plans to continue PFAS sampling and monitoring regulations. The development of this dashboard provided a path for FWSA to understand the cost of implementing improvements to reduce hauling costs and justification to continue with the status quo. As conditions evolve, FWSA can continue to use the EBAT to evaluate changing conditions. Case Study 2: Dorsey Run Drying Technology Evaluation The Dorsey Run Advanced Wastewater Treatment Plant (AWWTP), located in Jessup, MD, is permitted to treat 2 mgd. The AWWTP uses lime stabilization and dewatering to produce a Class B biosolids product for land application. Maryland Environmental Service (MES), who owns and operates the AWWTP was interested in conducting an evaluation to explore implementation of thermal drying, to explore the following: 1.Long-term feasibility and cost of implementing a thermal drying system, 2.Consideration for producing a Class A product in lieu of current Class B product to expand options for beneficial use, and 3.Preparation for future implementation of gasification or pyrolysis if required due to possible future PFAS regulations, which requires dried material as the feedstock. Approach Historical data and plant capacity, and operational strategies were used to develop design loads and flows for a thermal drying system. Inquiries were put out to thermal drying manufacturers of three different technologies: belt, screw/paddle, and tray dryers. Manufacturer information from the vendor and from references was used to present advantages, challenges, and site-specific implementation considerations of each to MES. The evaluation suggested that paddle and screw dryers are most feasible for a facility of 2 mgd. A short list of three drying systems was established for further evaluation: Paddle #1, Screw, and Paddle #2. The next phase of evaluation included development of full capital and lifecycle costs. Comprehensive 20-year lifecycle costs for each drying system included: demolition and construction costs and O&M costs; including but not limited to manpower, utilities, and maintenance. Conceptual layouts were developed for each of the three drying systems, and the most conservative (largest) is shown in Figure 3. For all three alternatives the existing lime stabilization system would be demolished and an elevated platform for the drying system installed. Finally, a multi-criteria evaluation was completed using cost and non-cost criteria to determine the most favorable alternative. Results The 20-year lifecycle costs were one factor in the multi-criteria evaluation shown in Figure 4. The criteria and weightings were developed with input from MES to ensure the appropriate priority was given to each consideration. This desktop evaluation allowed MES to prepare for the next level in biosolids processing and understand the current vendor and technology landscape to make an informed decision in design. MES plans to wait to design the drying system due to budgeting constraints. It is anticipated that funding will be secured if and when regulations require it. At that time, they plan to install a thermal drying and PFAS destruction process.

This paper was presented at the WEF Residuals and Biosolids Conference, June 18-21, 2024.

SpeakerAmenta, Julianne

Presentation time

09:30:00

10:00:00

Session time

08:30:00

11:15:00

SessionProgram Drivers: Economics, Regulatory, and Market Considerations

Session number24

Session locationOklahoma City Convention Center, Oklahoma City, Oklahoma

TopicBiogas Utilization, Supercritical water oxidation, Thermal drying

Author(s)

Amenta, Julianne

Author(s)J. Amenta1, M. Blate1,

Author affiliation(s)Hazen and Sawyer 1; Hazen and Sawyer 1;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Jun 2024

DOI10.2175/193864718825159436

Volume / Issue

Content sourceResiduals and Biosolids Conference

Word count8

Description: Collaborative, Trigger-Based Biosolids Masterplan for Seven-Facility Municipality in...

Collaborative, Trigger-Based Biosolids Masterplan for Seven-Facility Municipality in the Chesapeake Bay Watershed

Abstract

The Anne Arundel County Department of Public Works (AACo) owns and operates seven (7) Water Reclamation Facilities (WRF): Annapolis Water Reclamation Facility (AWRF), Broadneck Water Reclamation Facility (BNWRF), Broadwater Water Reclamation Facility (BWWRF), Cox Creek Water Reclamation Facility (CCWRF), Maryland City Water Reclamation Facility (MCWRF), Patuxent Water Reclamation Facility (PWRF), and Piney Orchard Water Reclamation Facility (POWRF). The plants are distributed throughout Anne Arundel County, as shown in Figure 1, and range in size from approximately 1 million gallons per day (mgd) to 15 mgd. AACo maintains a contract with a single full-service provider (FSP) since the early 1990's who manages the entirety of the county's biosolids output. The FSP is responsible for operating the dewatering and Class B alkaline stabilization at AWRF, BNWRF, BWWRF, MCWRF, and PWRF; transporting liquid, unstabilized solids from POWRF to the PWRF; and processing a minimum of 25% of the total volume of unstabilized cake to meet Class A/EQ standards. The Class A/EQ requirement is being met by processing all the solids generated at CCWRF to meet Class A/EQ standards. Class B alkaline-stabilized biosolids are transported to a long-term storage lagoon or to permitted land application sites in Maryland, Virginia, or Pennsylvania. AACo maintains no on-site storage for dewatered cake, requiring off-site transport to storage, beneficial use, or disposal each day dewatering processes operate. To meet the Class A/EQ requirement, unstabilized solids are transported by the FSP to the FSP's Watershed Resource Center for processing via alkaline addition and pasteurization. In the face of current regulatory trends, diminishing end-use outlets, and emerging biosolids treatment technologies a new, holistic approach to managing the County's biosolids is being developed in collaboration between County staff and Hazen and Sawyer. The intent of this project is to develop a long-term biosolids management plan that will address these challenges, and was approached through four unique phases: initiate phase, comprehend phase, explore phase, and converge phase, as shown on Figure 2. 1 - Initiate phase: the project team investigated all of AACo facilities and operational data to understand the existing conditions of each WRF and their operational metrics. Then an end-use market study and regulatory assessment was conducted to build a comprehensive market assessment that would inform the next phase. 2 - Comprehend phase: a set of screening criteria and associated weights were developed, in a collaborative process with all project stakeholders, through a series of stakeholder engagement workshops. The weighted criteria would be subsequently utilized to rank and score biosolids management options against one another. 3 & Explore phase: An evaluation of regionalized and/or centralized location for the biosolids processing alternative. 4 & Converge phase: To maximize flexibility for the County, a trigger-based roadmap was developed that outlined the best possible biosolids management track should one of several no-go criteria be satisfied. To this end, the Masterplan was structured in such a way that a maximum of capital dedicated to a previous management track be shunted to the new, alternate track, that would circumvent (subvert?) the no-go trigger. Hazen and AACo worked and is working collaboratively through the project to develop a long-term solution for AACo. Some of the major challenges AACo faces include: - Large distances between WRFs, as well as locations of WRFs in relation to residential areas limiting the location for a Centralized/regional facility. - Potential long-term unsustainability of land application related to current and future regulatory trends. - Land-application Issues in MD/Chesapeake Bay. The world of options of potential biosolids management alternatives which will be evaluated as part of the project include: Gasification/ pyrolysis, Anaerobic digestion, advanced anaerobic digestion, anaerobic digestion coupled with thermal drying, third-party, composting, and thermal drying. In order to score and rank the alternatives against one another a set of criteria were developed which include: Technical, Economic, Environmental, and Social. A weight is assigned, as determined by AACo, to each criteria to allow for scoring and ranking. To address regionalization, a multi-facility tool has been developed. The tool is capable of tracking solids from various plants to singular or multiple outlets while also varying the type of treatment alternatives. The tool also tracks green house gas emissions and costs, providing a user-friendly dashboard of the findings. Additionally, a tool is being developed which will serve as a digital twin of the selected alternative. The digital twin will be capable of tracking energy and solids through a user-friendly dashboard. The project will be complete by the time of the presentation and will be presented by both AACo and Hazen. The presentation will provide a clear, concise path for master planning for utilities with multiple facilities.

This paper was presented at the WEF Residuals and Biosolids Conference in Columbus, Ohio, May 24-27, 2022.

SpeakerBlate, Micah

Presentation time

14:30:00

15:00:00

Session time

13:30:00

17:00:00

Session number02

Session locationGreater Columbus Convention Center, Columbus, Ohio

TopicMaster Planning, Regionalization, Strategic Plan

Author(s)

M. Blate

Author(s)M. Blate1; A. Thomas2; J. Howard3; C. Saunders4; C. Portner5

Author affiliation(s)Residuals and Biosolids Speaker; 1Residuals and Biosolids Speaker; 2Residuals and Biosolids Speaker; 3Anne Arundel County DPW; 4Hazen and Sawyer; 5

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date May 2022

DOI10.2175/193864718825158434

Volume / Issue

Content sourceResiduals and Biosolids

Word count13

Cost of Removing PFAS from WRRF Effluent and Biosolids

Abstract

This study developed capital and operation and maintenance (O&M) cost estimates and curves to remove and destroy per- and polyfluoroalkyl substances (PFAS) from municipal water resource recovery facility (WRRF) effluent and biosolids. Class 5 cost estimates (-30%/+50%) for the assumed design bases were estimated based on vendor quotes and standard design practices for combinations of technologies pre-screened to be both commercially applied and effective at PFAS separation and/or destruction. Three treatment alternatives were developed for 0.1 to 10 MGD of tertiary treated WRRF effluent and two treatment alternatives were developed for 1.0 to 10 dry tons per day (dtpd) of dewatered WRRF biosolids. Estimated costs for a 10 MGD facility producing 10 dptd biosolids are approximately $79 to $250 million in capital costs and $50 to $20 million in annual operating costs, including consideration of all alternatives developed. Cost per mass of targeted PFAS removed (7 compounds for WRRF effluent and 9 compounds for WRRF biosolids) ranged from $370,000 per pound of PFAS removed from a 50 dptd WRRF biosolids treatment facility to $8 million per pound of PFAS removed from a 0.1 MGD WRRF effluent treatment facility. These costs do not include any retrofits needed to add tertiary treatment upstream of PFAS separation processes for WRRF effluent or to achieve 15%-25% solids content prior to PFAS destruction processes for WRRF biosolids.

This study developed capital and O&M cost estimates to remove and destroy per- and polyfluoroalkyl substances (PFAS) from municipal water resource recovery facility (WRRF) tertiary effluent and dewatered biosolids. Estimated costs for a 10 MGD/10 dtpd facility are approximately $79 to $250 million in capital costs and $50 to $20 million in annual operating costs. 20-year costs per mass of PFAS removed ranged from $370,000 per pound to $8 million per pound of PFAS removed.

SpeakerLing, Alison

Presentation time

16:30:00

17:00:00

Session time

15:30:00

17:00:00

SessionPFAS Impacted WRFs: Knowledge Update

Session locationRoom S401d - Level 4

TopicDisinfection and Public Health, Intermediate Level, PFAS, Research and Innovation, Utility Management and Leadership

Author(s)

Ling, Alison

Author(s)A. Ling 1; B. Vermace 2 ; A. McCabe 3; K. Wolohan 4; D. Dursun 5; M. Blate 6; M. Abu-Orf 6; S. Kyser 7; A. Ling 1;

Author affiliation(s)Department of Civil Engineering, University of St. Thomas 1; Barr Engineering Company 2 ; Barr Engineering Company 3; Barr Engineering Company 4; Hazen and Sawyer 5; Hazen and Sawyer 6; Hazen and Sawyer 6; Minnesota Pollution Control Agency 7; Department of Civil Engineering, University of St. Thomas 1;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825159129

Volume / Issue

Content sourceWEFTEC

Word count10

Description: Evaluating Innovative and Sustainable Treatment Options for Biosolids (WRF Project...

Evaluating Innovative and Sustainable Treatment Options for Biosolids (WRF Project #5169)

Abstract

Introduction : Biosolids are an organic and nutrient-rich product that are an important and valuable resource than can be used beneficially to support the advancement of the circular water economy. However, the market for the beneficial use of biosolids has been increasing challenged by concerns regarding high cost and limited land application opportunities, public perception, and contaminants of emerging concerns (CECs), such as per- and polyfluoroalkyl acids (PFAS) and microplastics. In response to these rising challenges, a range of innovative biosolids management alternatives have been emerging that can help utilities overcome some of these challenges. To comprehensively understand the potential of innovative biosolids management alternatives to address these challenges, a holistic evaluation framework (Figure 1) was developed. Objective: The information presented provides valuable and practical information to utilities including: 1) definition, function, and level of readiness of innovative biosolids treatment technologies and 2) a market assessment and value of the various end products identified through the technology screening. The proposed presentation will inform utilities of emerging technologies to address specific challenges, offer insight to different end-products from innovative technologies, and provide an update on the project. At the time of presentation most of the project should be completed. Status: The project is funded by the Water Research Foundation (WRF 5169) and will produce an adaptable tool that utilities can use to select suitable, practical, and sustainable innovative technologies for implementation. The project is ongoing and will be completed the second half of 2025, and includes the following tasks: Task 1: Technology Capture and Identification of Innovative Technologies was conducted as the first task in this project to clearly identify the borders of the research and align the project with the main objectives. This task involved a comprehensive evaluation of available information related to recent biosolids treatment technologies and sustainable management practices to capture innovative technologies. Information on innovative technologies must come from a variety of sources to fully capture what exists. A multiprong approach was executed to collect information from publications, water utilities, and vendors. Task 2: End Product Evaluation consisted of evaluations of end-of-process residual products from the selected innovative technologies in Task 1 (i.e., not including WWTP-internal technologies such as thickening). The objective of the evaluation was to generate information to inform the selection of technologies for case study and life cycle assessment development in Task 3 and Decision Support Tool development in Task 5. Task 3: Technology Screening was started following identification of innovative biosolids treatment technologies and end-product evaluation. This task consists of the development of technology screening criteria and shortlisting technologies for case studies (Task 4) with a multi-criteria decision-making support tool. Task 3: Technology Screening was initiated following technology capture and end-product evaluation. It consists of technology screen criteria development and technology shortlisting for the following case studies. Task 4: Case Studies and Life Cycle Analysis started upon the identification of technologies for case studies. A suite of surveys was developed to collect operational, financial, and life cycle analysis information from technology providers and users. Emerging Opportunities add-on Project: The add-on project extends the scope of the project to perform a comparative life cycle analysis (LCA) of biosolids management via conventional anaerobic digestion and emerging/innovative biosolids treatment technologies. The objective of the add-on project is to understand the benefits and trade-offs associated with innovative technologies in comparison to conventional biosolids treatment. Methodology: The comprehensive technology review and evaluation gathered information from more than 140 references, including published literature (focused on peer-reviewed literature), gray literature (information from vendors, including WRF's TechLink), information from various associations, and responses from an online survey. Once the initial number of innovative technologies was compiled, several screenings were conducted to determine applicability and if it would advance to further evaluation. Technologies captured from the comprehensive search were required to provide at least one of the following benefits compared to established technologies to be considered as 'innovative technology.' - Reduce biosolids quantity. - Improve end-product quality. - Enhance energy generation. - Reduce greenhouse gas emissions. - Reduce emerging contaminants. The findings from the initial evaluation were then screened to determine whether the technology is classified as 'innovative,' in alignment with the definition developed by the EPA (1). The innovative biosolids management technologies identified produce a variety of valuable products. To assess the markets for these products, an evaluation was conducted comparing the value of these end products to a standard of Class A/EQ dewatered cake. The suite of end products evaluated is presented in Table 1. Information was gathered from various sources including scientific journal articles, industry reports, technology vendors, characterization data, and professional experience. End-products, including a baseline product of Class A/EQ dewatered cake, were assessed on the following categories: - Inherent Value - Market Suitability / Access - Cost of Management / Market Value - Contaminants of Emerging Concern Removal Findings Following the initial screening 35 technologies met the defined criteria for innovation, seen in Table 2. The results from this evaluation will be presented on an accessible interactive dashboard for utilities and other interested parties (Figure 2). The presented information will include definitions, fact sheets, benefits to existing technologies and more. The innovative technologies identified resulted in a variety of end products that were further evaluated in the context of the existing market. Based on the comprehensive literature review (Task 1) that gathered information from published literature (focused on peer-reviewed literature), gray literature (information from vendors, including WRF's TechLink), information from associations, and responses from a distributed online survey, a total number of 40 innovative biosolids treatment technologies were identified and categorized by their functionalities. Technology Screening (Task 3) aims to shortlist technologies identified in Task 1 for detailed case studies. Previously, the team developed an approach that utilize a muti-criteria decision making support tool and a comprehensive set of screening criteria that encompassed technical and regulatory performance, operation and maintenance, sustainability, social impacts, and end-product evaluation. When executing the approach, the team encountered the following issues: 1) limited data availability for innovative technologies; 2) potential bias and limited knowledge in qualitative rating; 3) results' sensitivity to assumptions. To minimize bias and errors, the team decided to revise the approach for Task 3 by eliminating the criteria that require judgement or experience, such as social impacts, operation and maintenance, and costs. Additionally, the screening process is strictly using technical and factual information. The revised task approach workflow is shown in Figure 3. The level of implementation includes bench-scale, small pilot scale, large pilot scale, and full scale. Technologies that have been implemented at large pilot or full scale. Table 4 shows the applicability of the four criteria to different technology categories, and three key parameters -- product solids content, volatile solids reduction (VSR), and end-product evaluation, were selected to evaluate the performance. Regulatory resilience refers to a technology's ability to meet future regulations such as PFAS limits in biosolids and diversion of biosolids from landfill. Technology classification: E -- Enhancement/improvement of established technology: require specific criteria for advancing; A -- Addition to an existing process to improve performance: require specific criteria for advancing; D -- Disruptive Technology is a technology that completely changes the way we process biosolids. The five technologies recommended for case studies are summarized in Table 5.

This paper was presented at the WEF Residuals & Biosolids and Innovations in Treatment Technology Joint Conference, May 6-9, 2025.

SpeakerBlate, Micah

Presentation time

14:30:00

14:50:00

Session time

13:30:00

15:00:00

SessionConsiderations for Long-Term Biosolids Planning

Session number5

Session locationBaltimore Convention Center, Baltimore, Maryland, USA

TopicAnaerobic co-digestion, Biomethane, Lipids/proteins/carbohydrates ratio, TWAS, Manure, SSO, Biosolids treatment, Circular Economy, Co-Digestion With Other Organic Sources, Market Analysis, Master Planning, PFAS/Emerging Contaminants, Resiliency, Resource Recovery, Sustainability, Triple Bottom Line Plus

Author(s)

Blate, Micah, Sun, Anne, Abu-Orf, Mohammad, Knowles, Paul, Lewis, Asa

Author(s)M. Blate1, A. Sun1, M. Abu-Orf1, P. Knowles1, A. Lewis1

Author affiliation(s)Hazen and Sawyer, 1

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date May 2025

DOI10.2175/193864718825159771

Volume / Issue

Content sourceResiduals and Biosolids Conference

Word count12

Evaluating Innovative and Sustainable Treatment Options for Biosolids (WRF Project No. 5169)

Abstract

Introduction: Biosolids are an organic and nutrient-rich product that are an important and valuable resource than can be used beneficially to support the advancement of the circular water economy. However, the market for the beneficial use of biosolids has been increasing challenged by concerns regarding high cost and limited land application opportunities, public perception, and contaminants of emerging concerns (CECs), such as per- and polyfluoroalkyl acids (PFAS) and microplastics. In response to these rising challenges, a range of innovative biosolids management alternatives have been emerging that can help utilities overcome some of these challenges. To comprehensively understand the potential of innovative biosolids management alternatives to address these challenges, a holistic evaluation framework (Figure 1) was developed.

Objective: The information presented provides valuable and practical information to utilities including: 1) definition, function, and level of readiness of innovative biosolids treatment technologies and 2) a market assessment and value of the various end products identified through the technology screening. The proposed presentation will inform utilities of emerging technologies to address specific challenges, offer insight to different end-products from innovative technologies, and provide an update on the project. At the time of presentation most of the project should be completed. Status:The project is funded by the Water Research Foundation (WRF 5169) and will produce an adaptable tool that utilities can use to select suitable, practical, and sustainable innovative technologies for implementation. The project is ongoing and will be completed the second half of 2025, and includes the following tasks:
Task 1: Technology Capture and Identification of Innovative Technologies
Task 2: End Product Evaluation
Task 3: Technology Screening
Task 4: Case Studies and Life Cycle Analysis

Emerging Opportunities add-on Project: The add-on project extends the scope of the project to perform a comparative life cycle analysis (LCA) of biosolids management via conventional anaerobic digestion and emerging/innovative biosolids treatment technologies. The objective of the add-on project is to understand the benefits and trade-offs associated with innovative technologies in comparison to conventional biosolids treatment.

Methodology: The comprehensive technology review and evaluation gathered information from more than 140 references, including published literature (focused on peer-reviewed literature), gray literature (information from vendors, including WRF's TechLink), information from various associations, and responses from an online survey. Once the initial number of innovative technologies was compiled, several screenings were conducted to determine applicability and if it would advance to further evaluation. Technologies captured from the comprehensive search were required to provide at least one of the following benefits compared to established technologies to be considered as 'innovative technology.'

The innovative biosolids management technologies identified produce a variety of valuable products. To assess the markets for these products, an evaluation was conducted comparing the value of these end products to a standard of Class A/EQ dewatered cake. The suite of end products evaluated is presented in Table 1. Information was gathered from various sources including scientific journal articles, industry reports, technology vendors, characterization data, and professional experience. End-products, including a baseline product of Class A/EQ dewatered cake, were assessed for various categories.

Findings Following the initial screening 35 technologies met the defined criteria for innovation, seen in Table 2. The results from this evaluation will be presented on an accessible interactive dashboard for utilities and other interested parties (Figure 2). The presented information will include definitions, fact sheets, benefits to existing technologies and more. The innovative technologies identified resulted in a variety of end products that were further evaluated in the context of the existing market.

Technology Screening (Task 3) aims to shortlist technologies identified in Task 1 for detailed case studies. Previously, the team developed an approach that utilize a muti-criteria decision making support tool and a comprehensive set of screening criteria that encompassed technical and regulatory performance, operation and maintenance, sustainability, social impacts, and end-product evaluation. The task approach workflow is shown in Figure 3.

The level of implementation includes bench-scale, small pilot scale, large pilot scale, and full scale. Technologies that have been implemented at large pilot or full scale. Table 4 shows the applicability of the four criteria to different technology categories, and three key parameters — product solids content, volatile solids reduction (VSR), and end-product evaluation, were selected to evaluate the performance. Regulatory resilience refers to a technology's ability to meet future regulations such as PFAS limits in biosolids and diversion of biosolids from landfill.

The five technologies recommended for case studies are summarized in Table 5.

This paper was presented at WEFTEC 2025, held September 27-October 1, 2025 in Chicago, Illinois.

Presentation time

13:30:00

13:45:00

Session time

13:30:00

15:00:00

SessionBiosolids Planning from WRF to the WRRF

Session locationMcCormick Place, Chicago, Illinois, USA

TopicBiosolids & Residuals

Author(s)

Blate, Micah, Sun, Anne, Abu-Orf, Mohammad, Knowles, Paul, Lewis, Asa

Author(s)M. Blate1, A. Sun1, M. Abu-Orf1, P. Knowles1, A. Lewis1

Author affiliation(s)Hazen and Sawyer1

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Sep 2025

DOI10.2175/193864718825160067

Volume / Issue

Content sourceWEFTEC

Word count13

Description: Evaluation of Innovative Biosolids Management Strategies with Considerations of...

Evaluation of Innovative Biosolids Management Strategies with Considerations of Circular Water Economy

Abstract

The circular water economy optimizes water resources and minimizes waste and emissions by recycling, recovering and regeneration. Biosolids, an organic and nutrient-rich byproduct of wastewater treatment, are an important and valuable resource that can be beneficially used to support improvements to the circular water economy. However, growing challenges associated with greenhouse gas emissions, limited land and resources, contaminants of emerging concerns (CECs), such as PFAS and microplastics, have begun to threaten the beneficial use of biosolids. In response to the rising challenges, a plethora of innovative biosolids management alternatives have been emerging, providing utilities new perspectives on biosolids treatment, end-use, and pathways to advance the circular water economy via beneficial co-product(s) generation, emissions control/capture, and cost reduction. To comprehensively understand the potential of innovative biosolids management alternatives in addressing these challenges, a holistic evaluation framework (Fig. 1) was developed. The framework encompasses environmental impacts, social impacts, cost-effectiveness, as well as integrability into the circular water economy through the sustainable management of end-products. This presentation will provide valuable and practical information to utilities including: 1) definition, function, and level of readiness of innovative biosolids treatment technologies and 2) a holistic evaluation framework developed to screen innovative technologies for implementation, featuring end-product evaluations. The presentation will inform utilities of innovative solutions to rising wastewater treatment challenges, offer insights to different end-products from innovative technologies, and provide an adaptable tool that utilities can use to select suitable, practical, and sustainable innovative technology(ies) for implementation. This project is funded by the Water Research Foundation (WRF 5169). Innovative Biosolids Treatment Technologies The comprehensive evaluation gathered information from 140 references, including published literature (focused on peer-reviewed literature), gray literature (information from vendors, including WRF's TechLink), information from associations, and responses from a distributed online survey. Technologies captured from the comprehensive search were required to provide at least one of the following benefits compared to established technologies to be considered as 'innovative technology': - Reduce biosolids quantity. - Improve end-product quality. - Enhance energy generation. - Reduce GHG emissions. - Address concerns on emerging contaminants. The findings from this initial evaluation were screened to determine whether the technology is classified as 'innovative,' in alignment with the definition developed by the EPA (2006), where at least one of the following categories must be met by the technology: - Tested at a full-scale demonstration site in this country. - Available and implemented in the United States (U.S.) for less than 5 years. - There is some degree of initial use. - Established technologies overseas with some degree of initial use in the U.S. Within the technology capture, there were 36 innovative treatment technologies identified. The technologies are grouped under several unit operations; thermal conversions, stabilization, thickening, dewatering, drying, and other innovative processes. The results from this evaluation will be presented on an interactive dashboard accessible to utilities and other interested parties. Holistic Evaluation Framework for Innovative Treatment Technologies The framework embraces end-product evaluation, technical capabilities, operation and maintenance requirements, social impacts, regulatory performance, and environmental impacts. The viability of end product biosolids and their co-products, such as energy content, plays a key role in closing the unsustainable loop of resource release to the environment. To this end, end-products are evaluated through the lenses of waste diversion, materials cycling and their benefit predominantly in the natural environment in comparison to the traditional management of biosolids. Key considerations of end-product evaluation are their inherent values, cost recovery potential, market viability, and destruction of CECs. Inherent value reflects the value of constituents in the end-products, such as nutrients and organic matter, and the indirect value of their use (e.g. energy content, carbon offset generation potential). Aggregated inherent values are not indicative of the market value of residuals, but are rather an indication of potential market access and suitability for beneficial use. Management fees and potential market values present opportunities for cost recovery which is typically not available to the baseline product of dewatered biosolids. The values are estimated based on the project team's experience, reports from US contractors, reports from technology vendors, or professional opinion. Figures 2 and 3 present an example result of inherent value and cost recovery potential of the end-products of innovative thermal conversion technologies. The range of beneficial constituents inherent within these residuals will influence market access. Residual products are assessed for their suitability for a range of traditional and innovative markets. Market suitability was assessed on a scale of 0-1 (with 0 being no suitability/access and 1 being full access) based on the project team's experience, industry knowledge, and academic trials and reporting. The environmental impacts of innovative technologies are quantified through energy demand and the greenhouse gas emission during the operation of technology as well as the application of its end-products. Technical performance, operational and maintenance requirements provide information on the robustness, consistency, and scaling flexibility of innovative technologies, helping utilities assess the potential staffing and operating requirements. Social impacts are also included in the evaluation framework, accounting for public opinion and nuisance risks such as odor and noise. The weights of evaluation categories and criteria represent the relative importance of each one and serve as channels to incorporate stakeholders' opinion. The weights are determined based on utilities, project advisory committee, and other stakeholders. Conclusion This project aims to assist utilities in understanding the cross-section and applicability of innovative and sustainable technologies that can fit into a circular water economy, while also meeting the current pressures being faced by the biosolids management community. This presentation will provide practical information on emerging solutions to the challenges in biosolids management and share tools that utilities can use to select options to meet their unique needs.

This paper was presented at the WEF Residuals and Biosolids Conference, June 18-21, 2024.

SpeakerSun, Yian

Presentation time

13:30:00

14:00:00

Session time

13:30:00

15:00:00

SessionLand Application

Session number17

Session locationOklahoma City Convention Center, Oklahoma City, Oklahoma

TopicCircular Economy, Innovative Technology, Research

Author(s)

Sun, Yian

Author(s)Y. Sun1, C. Evans2, M. Teshima2, A. Lewis1, D. Dursun1, M. Abu-Orf M. Blate1

Author affiliation(s)Hazen and Sawyer 1; Sylvis 2; Sylvis 2; Hazen and Sawyer 1; Hazen and Sawyer 1; Hazen and Sawyer1; Hazen and Sawyer1;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Jun 2024

DOI10.2175/193864718825159442

Volume / Issue

Content sourceResiduals and Biosolids Conference

Word count13

Exciting Applications of Machine Learning in the Water Industry

Abstract

Two applications of machine learning (ML) in the water space were developed to illustrate the power of these tools: 1) A fully deployed model predicting influent wastewater flow for wet weather management. 2) A desktop model predicting the percent total solids (%TS) in cake on any given day. Both of these ML models provide operational staff with insight that could not be generated through other means (i.e., mechanistic models) by virtue of the way the machine learning algorithms look for explanatory variables.

SpeakerBlate, Micah

Presentation time

13:30:00

13:50:00

Session time

13:30:00

15:00:00

SessionData-Driven Engineering through Data Analytics

Session number303

TopicFacility Operations and Maintenance, Intelligent Water, Resilience, Disaster Planning and Recovery

Author(s)

Micah Blate

Author(s)E. Bailey4; D. Dursun3; K. Bilyk2; M.D. Blate1;

Author affiliation(s)Hazen and Sawyer, Philadelphia, PA1Hazen and Sawyer, Raleigh, NC2Hazen and Sawyer, San Diego, CA3Raleigh Water, Raleigh, NC4

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2021

DOI10.2175/193864718825158047

Volume / Issue

Content sourceWEFTEC

Word count10

Machine Learning for Dewatering Optimization

Abstract

The water industry is beginning to recognize and apply machine learning (ML) as a tool to optimize system operations in a way that was not possible even a few years ago. This is primarily due to advances in online instrumentation, data management and Cloud computing. At its simplest, ML is learning from data. Every day, various types of data are recorded on a massive scale throughout the water industry, and ML can be used to analyze these complex datasets, helping operators by leveraging the objective and powerful capabilities of computers to identify and utilize patterns from the data that a human may not recognize. Machine learning models are developed through model training, after which they are used to make predictions on 'unseen data' & real-time data that will be brought into the model to provide knowledge or insights for decision-making. Well-trained (or calibrated) models can explore and process massive datasets in real time while also providing extremely rapid predictions, insights, and/or recommendations for operators-a difficult and sometimes impossible task for a human, especially in a short time frame. That said, data-driven ML tools are meant to assist and not replace human intelligence, and they do not have to be complicated or involve massive amounts of data to be useful. Operational experience and expertise, rather, is fundamental to successful ML development, interpretation, and implementation. The use of water experts to develop an ML model is critical for integrating the science of water into the model. Once in production, it will always be important for a human to review the recommendations of the model, periodically verify the model is continuously learning, and apply their own judgment and experience to the question at hand. One of the most compelling benefits of building ML models is that is allows the user to always have an up-to-date model of their system. This differs from most mechanistic modeling software packages that must be recalibrated by a human every couple of years and that likely have significant drift during that time period (e.g., biological process simulators, collection system models). In addition, ML models can account for some real-life complexity and nuances that may not be captured in mechanistic models (e.g., biological phosphorus modeling is often a simplified version of reality). This presentation will describe two applications of ML in the water space-one a fully deployed model predicting influent wastewater flow for wet weather management, and the second a desktop model predicting the percent total solids (%TS) in cake on any given day. Cake %TS Predictor We endeavored to determine if we could develop an empirical relationship between explanatory variables and dewaterability. The value propositions are that (1) enhanced understanding of the variables contributing to improved dewaterability allows the user to operate optimally to reduce hauling and disposal costs, and (2) polymer dose could be increased to assist on days with poor dewaterability. Five years of data from a plant averaging 22% cake with an average polymer dose of 42 lb/DT was used for training. Seven explanatory variables including the influent carbon to nitrogen ratio times ash content (C/N*ash) were used to predict %TS with a precision of +/- 0.4 %. Two separate models were generated to gain better insight into how the explanatory variables affect dewaterability. For example, both showed a positive correlation between increased C/N*ash and %TS in cake as other studies have shown (CNash & A novel parameter predicting cake solids of dewatered digestates, O.K. Svennevik et al. / Water Research 158 (2019) 350-358). Figure 1 compares the predicted and observed results. These models concluded that only 20 percent of the factors influencing dewatering are truly fixed properties, meaning the remainder are operational variables that could be modified to optimize dewaterability. Work is ongoing to better understand how these insights generated from ML compliment the ongoing mechanistic research in this area, and to see if deployment is of interest at any utilities.

This paper was presented at the WEF Residuals and Biosolids Conference in Columbus, Ohio, May 24-27, 2022.

SpeakerBlate, Micah

Presentation time

13:30:00

14:00:00

Session time

13:30:00

16:45:00

Session number14

Session locationGreater Columbus Convention Center, Columbus, Ohio

TopicDewaterability, Dewatering Optimization, Machine Learning

Author(s)

M. Blate

Author(s)M. Blate1; D. Dursun2; K. Bilyk3

Author affiliation(s)Residuals and Biosolids Speaker; 1Hazen and Sawyer; 2Hazen and Sawyer; 3

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date May 2022

DOI10.2175/193864718825158418

Volume / Issue

Content sourceResiduals and Biosolids

Word count6

Market Value for Various Biosolids Products from Innovative Biosolids Technologies (WRF Project #5169)

Abstract

...Introduction: Biosolids are an organic and nutrient-rich product that are an important and valuable resource than can be used beneficially to support the advancement of the circular water economy. However, the market for the beneficial use of biosolids has been increasing challenged by concerns regarding high cost and limited land application opportunities, public perception, and contaminants of emerging concerns (CECs), such as per- and polyfluoroalkyl acids (PFAS) and microplastics. In response to these rising challenges, a range of innovative biosolids management alternatives have been emerging that can help utilities overcome some of these challenges. To comprehensively understand the potential of innovative biosolids management alternatives to address these challenges, a holistic evaluation framework (...Figure 1) was developed. ...Objective: The information presented provides valuable and practical information to utilities including: 1) definition, function, and level of readiness of innovative biosolids treatment technologies and 2) a market assessment and value of the various end products identified through the technology screening. The proposed presentation will inform utilities of emerging technologies to address specific challenges, offer insight to different end-products from innovative technologies, and provide an assessment of diverse end-products from an aggregated dollar value perspective. ...Status: The project is funded by the Water Research Foundation (WRF 5169) and will produce an adaptable tool that utilities can use to select suitable, practical, and sustainable innovative technologies for implementation. The project is ongoing and will be completed the second half of 2024. Three of the six tasks have been completed. ...Methodology: The comprehensive technology review and evaluation gathered information from more than 140 references, including published literature (focused on peer-reviewed literature), gray literature (information from vendors, including WRF's TechLink), information from various associations, and responses from an online survey. Once the initial number of innovative technologies was compiled, several screenings were conducted to determine applicability and if it would advance to further evaluation. Technologies captured from the comprehensive search were required to provide at least one of the following benefits compared to established technologies to be considered as 'innovative technology.'

*Reduce biosolids quantity.

*Improve end-product quality.

*Enhance energy generation.

*Reduce greenhouse gas emissions.

*Reduce emerging contaminants. The findings from the initial evaluation were then screened to determine whether the technology is classified as 'innovative,' in alignment with the definition developed by the EPA (1). The innovative biosolids management technologies identified produce a variety of valuable products. To assess the markets for these products, an evaluation was conducted comparing the value of these end products to a standard of Class A/EQ dewatered cake. The suite of end products evaluated is presented in Table 1. Information was gathered from various sources including scientific journal articles, industry reports, technology vendors, characterization data, and professional experience. End-products, including a baseline product of Class A/EQ dewatered cake, were assessed on the following categories:

*Inherent Value

*Market Suitability / Access

*Cost of Management / Market Value

*Contaminants of Emerging Concern Removal ...Findings Following the initial screening 35 technologies met the defined criteria for innovation, seen in ...Table 2. The results from this evaluation will be presented on an accessible interactive dashboard for utilities and other interested parties (...Figure 2). The presented information will include definitions, fact sheets, benefits to existing technologies and more. The innovative technologies identified resulted in a variety of end products that were further evaluated in the context of the existing market. To contextualize the value of the various end products, they were evaluated from a cost perspective, specifically aggregated dollar value of nutrients and carbon, shown in ...Figure 3. On a per-dry ton basis, biochar and struvite have the highest inherent value (...Figure 3), and biochar has value in the greatest number of constituents/properties, suggesting a relatively wider market applicability. Market access (...Table 3), which is based on professional opinion/experience, assigns a score of 0 (low access) to 1 (high access) and supports the assertion that biochar has wide market access. The 'net market benefit' (...Figure 4) equals the market access score multiplied by the average cost of management and expresses the potential for cost recovery. The results of the market evaluation clearly show the positive net market benefit of end products from innovative biosolids management technologies in comparison to the baseline Class A/EQ biosolids. Each end product greatly reduces costs to the utility compared to Class A/EQ biosolids, and often even had potential to bring revenue to the utility. The identified innovative biosolids treatment technologies can diversify end product outlets by providing a wider range of accessible markets.

The information presented aims to provides valuable and practical information to utilities through a market assessment and valuation of the various end-products identified through the technology screening. The results will inform utilities of emerging technologies to address specific challenges, offer insight to different end-products from innovative technologies, and provide an assessment of end-products from an aggregated dollar value perspective.

SpeakerLewis, Asa

Presentation time

16:00:00

16:30:00

Session time

15:30:00

17:00:00

SessionPFAS in Biosolids: Remove and Track it

Session number417

Session locationRoom 238

TopicBiosolids and Residuals, Intermediate Level, PFAS

Author(s)

Lewis, Asa, Evans, Christian, Teshima, Mark, Sun, Yian, Abu-Orf, Mohammad, Knowles, Paul, Higgins, Matthew, Blate, Micah

Author(s)A. Lewis1, C. Evans2, M. Teshima2, Y. Sun3, M.M. Abu-Orf1, P. Knowles4, M.J. Higgins5, M.D. Blate1

Author affiliation(s)1Hazen and Sawyer, PA, 2Sylvis Environmental, BC, 2, 3Hazen and Sawyer, CA, 4Hazen & Sawyer, NY, 5Bucknell University, PA

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2024

DOI10.2175/193864718825159578

Volume / Issue

Content sourceWEFTEC

Word count14

Troubleshooting Nitrification Process Upsets with a Robust Testing Protocol

Abstract

Introduction & Approach Wastewater utilities must often navigate biological process upsets due to the vulnerability of microbial processes to toxicity. Nitrification is particularly susceptible to impact from inhibitory substances (Bye et al., 2012; Xiao et al., 2015). This paper describes three WWTPs where deterioration in nitrification performance was troubleshooted successfully. Information in this paper is intended to support industry efforts to navigate process upset events at WWTPs. For each facility, operating data including flows, NH3, TN, TKN, airflows, DO, MLSS, and SRT were assessed. Additionally, WWTP influent and waste streams were analyzed for typical (ammonia, TKN, COD, sCOD) and potentially toxic (QACs, surfactants, amines, isothiazolones, phenols, peracetic acid, metals) compounds. Aerobic biomass activity was evaluated through specific oxygen uptake rate (sOUR) and substrate uptake rate (SUR) testing (Adani et al., 2001). Results and Conclusions Case Study 1 WWTP1 is a BNR facility with capacity of 7 mgd annual average (AA) flow and effluent TN limit of 8 mg/L AA. The treatment process contains aerobic basins and secondary clarifiers with no primary treatment. WWTP1 experienced loss of nitrification in 2022 and 2023, evidenced by elevated ammonia concentrations in the effluent. In 2022, sampling of the plant influent, as well as in the collection system indicated high QAC and zinc concentrations. Batch testing was performed on plant biomass spiked with the influent and collection system streams, showing inhibition of nitrification in the plant biomass as well as in a control biomass. Figure 1 shows data suggesting the continued presence of toxic substances in the plant. No increase in nitrification activity was observed using decanted biomass, suggesting a continued influx of toxicant to the WWTP. Increasing the aerobic volume in service resulted in partial recovery. The process ultimately recovered as influx of toxic substances in the plant influent abated and viable nitrifier inventory increased (1.5 months). In 2023, analyses of plant data indicated that the likely cause of elevated nitrogen in the effluent was nitrifier washout due to over-wasting. The facility was able to recover nitrification by reducing wasting rate and building up nitrifier inventory. The batch testing approach was found to be robust in determining the cause of the inhibition and informing recovery efforts through data analysis in combination with sOUR and SUR tests. A decision tree was provided to support future recovery efforts, outlining checks and proactive actions for prevention and timely resolution of issues (Fig 2). Case Study 2 WWTP 2 is a BNR facility with treatment capacity of 7.5 mgd AA and effluent TKN and TN limits of 3 mg/L (monthly) and 8 mg/L AA, respectively. The process includes primary clarifiers, BNR basins, secondary clarifiers, and gravity sand filters. In February 2022, the facility experienced near complete loss of nitrification. Influent characterization did not indicate toxicity in the plant influent. However, sOUR and SUR analyses on decanted biomass resulted in a clear and immediate increase in activity, suggesting the presence of inhibitory compounds in the liquid biomass matrix (Figure 3). sOURs did not change when using influent from WWTP2 versus a control facility, indicating that carbon removal was not impacted. Consequently, the facility increased wasting rate to accelerate washout of the embedded toxicant(s) from the process. The basins were then re-seeded with a fully nitrifying biomass from a nearby facility and a decision tree was provided (Figure 4). The chosen strategy of biomass wasting and re-seeding were successful in helping the facility recover nitrification. Case Study 3 WWTP 3 is BNR facility with Treatment capacity of 15 mgd AA and seasonal NH3-N limits (Winter: 18.5 mg/L; Summer: 6.5 mg/L). The process includes primary clarifiers, BNR basins, secondary clarifiers, and disinfection. In October 2020, the facility experienced a process upset characterized by slime growth, loss of nitrification, low DO, high SVIs, and elevated effluent cBOD, TSS and NH3-N. Operational data, microscopy, sampling, and toxicity testing indicated excessive sulfur may have caused the issues. Additionally, a number of industrial dischargers were identified, that had potentially caused previous process upsets. To combat future upsets, the following were recommended: (1) Routine examination of MLSS to identify early signs of deteriorating performance. (2) Addition of a selector zone for the selection of floc forming bacteria. (3) RAS chlorination (4) Installation of SentryTM probes to provide real-time monitoring of influent wastewater. Recommendations A comprehensive and robust protocol can help identify and address the process upset at WWTPs. The protocol proposed in this study includes review of facility performance leading up to and during the performance deterioration, waste stream characterization, and biomass activity testing. periodic sampling of non-routine constituents such as surfactants that are common nitrification toxicants, proactive monitoring of influent characteristics using sensors and sampling to provide early warning of potential detrimental impacts are recommended. Prompt response and robust testing can provide clear insight into causes of process upsets.

This paper was presented at the WEFTEC 2024 conference in New Orleans, LA October 5-9.

SpeakerPathak, Ankit

Presentation time

14:00:00

14:30:00

Session time

13:30:00

15:00:00

SessionInnovative Approaches to Address Traditional Operational Challenges

Session number211

Session locationRoom 344

TopicFacility Operations and Maintenance, Intermediate Level, Municipal Wastewater Treatment Design, Nutrients

Author(s)

Pathak, Ankit, Khunjar, Wendell, Seyedi, Saba, Blate, Micah, Sayles, Molly, Noteboom, Haley

Author(s)A. Pathak1, W. Khunjar2, S. Seyedi1, M.D. Blate3, M. Sayles1, H. Noteboom4

Author affiliation(s)1Hazen and Sawyer, VA, 2Hazen & Sawyer PC, VA, 3Hazen and Sawyer, PA, 4Hazen & Sawyer, NY

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2024

DOI10.2175/193864718825159496

Volume / Issue

Content sourceWEFTEC

Word count10

Description: Understanding Gasification for PFAS Removal in Residuals: Full-Scale Study Results...

Understanding Gasification for PFAS Removal in Residuals: Full-Scale Study Results from WRF Project 5107

Abstract

This abstract reports on results from the first PFAS testing in a full-scale operating municipal biosolids processing gasification facility, including air emission testing. The presence of PFAS in solids or biosolids has affected the beneficial use and disposal options in the US. The land application of biosolids reintroduces PFAS into the environment, potentially contaminating surface water and/or groundwater. Gasification/pyrolysis followed by thermal oxidation are processes that were considered successful in removing PFAS in biosolids.

In addition to the ability to remove PFAS from solids due to high temperature during the thermal oxidation part, gasification significantly reduces solids and recovers valuable energy from the solids. However, no full-scale facility has reported PFAS removal data from gasification operations, and full-scale PFAS air emission testing and data is also lacking.

This WRF funded project aimed to evaluate the performance and feasibility of a full-scale thermal drying and gasification facility for processing municipal sludge as feedstock, with a focus on its effectiveness in removing/destroying PFAS. Key objective of this project includes assessing the fate of selected PFAS through the thermal drying and gasification unit processes, performing mass and energy balances on metals and PFAS around the system and the various unit processes, and comparing the process's life-cycle cost to conventional solids treatment and beneficial use or disposal technologies. This study seeks to provide comprehensive insights into the potential of gasification for managing PFAS in biosolids effectively.

Figure 1- 1 shows a general schematic diagram of gasification/pyrolysis processes, which are thermochemical processes that decompose carbonaceous materials at elevated temperatures, typically ranging from 1,100-1,800°F, using stoichiometrically insufficient oxygen or no oxygen. Higher temperatures convert most carbon in the biosolids to syngas, resulting in an inert, sand-like material. Conversely, lower temperatures yield carbon-rich biochar suitable for various applications. The generated syngas is passed through the thermal oxidation process at temperatures >2000°F thus removing PFAS and generating energy that can be used in drying, and the gasification process itself. While most gasification technologies require feedstock greater than 75% TS, some technologies prefer feedstock between 50% - 70% TS. Furthermore, these technologies do not require stabilized biosolids.

The gasifier studied in this research is operating at the Edmonds facility in Washington and processing 30 wet tons per day dewatered combined and waste activated sludge solids. Figure 1-2 shows the process flow diagram of the tested facility that includes direct drum drying, gasification, thermal oxidation, air treatment and ancillary processes. The gasification operates at higher than usually practiced temperature, thus generating sand like material termed by the vendor as FLGSand. Sampling was conducted at nine (9) key points for PFAS and other solids constituents. Sampling included stack air sampling (Figure 1-3) for PFAS analysis-a first for such studies at two locations, before and after an activated carbon filter for air treatment. Collected samples from the FLGSand were analyzed by two independent laboratories for accuracy.

Mass and energy balance were conducted based on operational conditions and analytical data. As shown in Figure 1-4, the system processed approximately 550 dry lbs/hr) of dewatered cake, producing about 92 lbs/hr of inert product/sand, representing over a 95% mass reduction. The gasifier produced approximately 4.2 mbtu/hr of energy in the syngas, which is subsequently recovered as heat for the dryer. The dryer used approximately 2.5 mbtu/hr. The operation and inherent energy value of the solids resulted in a net positive energy balance.

The targeted PFAS load (g F/d) in the entire and split system are presented in Figure 1-5. Results from two different laboratories confirmed no PFAS was detected in the FLGSand. The overall process achieved a significant mass and volume reduction compared to the input. The heated air from the gasifier, after passing through the thermal oxidizer and heat exchanger, was used in the thermal dryer. This air has been reported to contain very little to no PFAS. However, the drying process caused the air to pick up trace concentrations of PFAS precursors and terminal products, which were released in the scrubber water and stack air at very low levels. On a mass loading basis, about 5% of the total input measured PFAS was released in the air and about 15% is recovered in the scrubber water. Granular activated carbon (GAC) can be practiced capturing ~ 90% of the PFAS concentration from the scrubber water, thus increasing the system overall PFAS removal efficiency. Also, it has been demonstrated that using regenerative thermal oxidation (RTO) can remove more than Also, it has been demonstrated that using regenerative thermal oxidation (RTO) on air can remove more than 95% of the measured PFAS.

In addition, the study measured PFOA and PFOS due to their regulatory significance. Data showed no detectable levels of these compounds in the solids output, trace PFOA in scrubber water, and negligible PFOA, PFOS in stack air. Additional analyses of TF and TOF on solids and liquids corroborated the findings of target PFAS analysis.

This paper was presented at WEFTEC 2025, held September 27-October 1, 2025 in Chicago, Illinois.

Presentation time

11:00:00

11:15:00

Session time

10:30:00

12:00:00

SessionThermal Treatment of PFAS in Biosolids

Session locationMcCormick Place, Chicago, Illinois, USA

TopicBiosolids & Residuals

Author(s)

Abu-Orf, Mohammad, Khan, Kamruzzaman, Blate, Micah

Author(s)M. Abu-Orf1, K. Khan1, M. Blate1

Author affiliation(s)Hazen and Sawyer1

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2025

DOI10.2175/193864718825160022

Volume / Issue

Content sourceWEFTEC

Word count15

Description: WRF Project# 5307: Evaluation of Source Separated Organic Feedstock Pretreatment and...

WRF Project# 5307: Evaluation of Source Separated Organic Feedstock Pretreatment and Management Practices

Abstract

INTRODUCTION This paper will provide the project approach and results for Water Research Foundation (WRF) Project# 5037 Evaluation of Source Separated Organic (SSO) Feedstock Pretreatment and Management Practices. The final report is scheduled for release in summer of 2022. SSO co-digestion with wastewater solids at Water Resource Recovery Facilities (WRRFs) offers promise to advance sustainability through beneficial reuse of the organic fraction of pre- and post-consumer waste streams (source separated organics), which would otherwise be disposed in landfills. Promoting SSO diversion from landfills to anaerobic digestion (AD) is predicated on SSO feedstock pretreatment to enhance the digestibility and conveyance of SSOs. This project, as funded by the Water Research Foundation, aims to comprehensively evaluate SSO pretreatment technologies with guidance from existing facilities to develop recommendations for SSO pre-treatment alternatives for utilities considering SSO diversion. The project has been divided into four tasks: 1.Task 1: Global Literature Review and Survey of Existing Technologies and Management Strategies 2.Task 2: Evaluation of Existing Technologies and Management Strategies 3.Task 3: Case Studies with a Wastewater Industry Focus 4.Task 4: SSO Pretreatment Analysis and Decision Tool This project provides guidance for utilities interested in SSO pre-treatment and co-digestion in order to: 1. Successfully build new or enhance existing SSO pretreatment and co-digestion programs, 2. Address challenges and opportunities involved with SSO pretreatment, 3. Identify SSO pretreatment requirements based on SSO feedstock quality and quantity, an 4.Determine capital and O&M costs and potential impacts on WRRFs. This Report will be published January 2023. APPROACH Information pertaining to SSO pretreatment was gathered from literature sources including conference proceedings, project reports, journal articles, and manufacturer documentation in conjunction with questionaries from utility and vendor partners, as well as case studies from domestic and international facilities. Using a four-task approach, information has been distilled into a literature review, fact sheets, case studies, and a SSO pre-treatment guidance tool. Further, this information has been compiled into a PowerBI dashboard. The compatibility and effectiveness of multiple SSO pretreatment technologies were evaluated with information gathered from currently operating facilities which informed the development of SSO pretreatment selection workflows. These workflows were constructed based on contaminant properties such as size and type to distinguish appropriate pretreatment technology selection. RESULTS AND FINDINGS Task 1. Global Literature Review Task 1 focused on gathering information related to the application of SSO pretreatment prior to AD which was assembled in a literature review. Results from the literature review were organized by features and capabilities of unit operations and processes (UOPs). Physical UOPs were the most frequently implemented SSO pretreatment technologies used for both initial and polishing steps as shown in Figure 1. In addition, package units were found to be very attractive for utilities seeking multiple technologies in series for efficient removal of numerous contaminants. A thorough list of pretreatment technology vendors was also provided as a reference for utilities planning pretreatment installations. Task 2. Existing Technologies and Management Strategies Evaluation Seventeen (17) utilities and technology providers, both in the US and abroad, were surveyed through the completion of a questionnaire inquiring about existing pretreatment facilities. The information gathered was summarized into factsheets (example shown in Figure 2) containing information such as process flow diagrams, facility details, lessons learned, and maintenance requirements. Major findings from Task 2 include: -Receiving pre-treated SSO is advantageous for controlling consistency and material quality. -Adequate storage should be provided at the receiving facility. -Removing contamination to the extent possible ensures that downstream equipment and digester(s) aren't adversely impacted by SSO. -Storing critical spare parts on site is recommended. Task 3. Case Studies Results Task 3 results contain insight from seven case studies focused on SSO pretreatment in the wastewater industry. Case studies provided detailed information related to each utility such as mass balances, facility financial information, construction characteristics, and anticipated maintenance schedules. Unit cost curves have been developed for the SSO pretreatment facilities (example shown in Figure 3) to provide an estimate of construction cost, O&M cost, biogas revenue, tipping fees, and inert disposal costs as a function of wet ton of waste. Overall, increasing facility size had decreasing unit costs due to economies of scale. Task 4. SSO Pretreatment Selection Guidance Much of the technology documentation accumulated through the literature review, database development, and case studies was instrumental in the development of multiple SSO pretreatment workflows to guide SSO pretreatment selection. Workflows created as part of Task 4 are structured by contaminant type, size, and physiochemical properties. For example, as shown in Figure 4, appropriate selection of metal and glass removal technologies is contingent on the material size and can be further distinguished by color, magnetism, mobility. DISCUSSION AND BENEFITS The collection of information provided in this study is vital for utilities considering SSO pretreatment by providing technology descriptions, financial information, process mass balances, and selection tools for utilities to functionally apply SSO pretreatment at existing or future anaerobic digestors. While previous studies have focused on AD optimization, there is limited information related to the nuances of SSO pretreatment operation and overall pretreatment effectiveness as discussed in this study. As facilities continue to push for more sustainable waste solutions, the application of SSO pretreatment technologies can be a cost-effective improvement in AD performance.

This paper was presented at the WEF/IWA Residuals and Biosolids Conference, May 16-19, 2023.

SpeakerBlate, Micah

Presentation time

16:15:00

16:45:00

Session time

13:30:00

16:45:00

SessionSession 14: Co-Digestion

Session number14

Session locationCharlotte Convention Center, Charlotte, North Carolina, USA

TopicCase Studies/Lessons Learned

Author(s)

M. Blate

Author(s)M. Blate1, M. Abu-Orf2, D. Dursun3, K. Landry4, C. Murray5, R. Sharp6,

Author affiliation(s)Hazen and Sawyer1; Manhattan College2

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date May 2023

DOI10.2175/193864718825158867

Volume / Issue

Content sourceResiduals and Biosolids

Word count14

WRF Project# 5307: Evaluation of Source Separated Organic Feedstock Pretreatment and Management Practices

Abstract

INTRODUCTION
This paper will provide the project approach and results for Water Research Foundation (WRF) Project# 5037 Evaluation of Source Separated Organic (SSO) Feedstock Pretreatment and Management Practices. The final report is scheduled for release in summer of 2022. SSO co-digestion with wastewater solids at Water Resource Recovery Facilities (WRRFs) offers promise to advance sustainability through beneficial reuse of the organic fraction of pre- and post-consumer waste streams (source separated organics), which would otherwise be disposed in landfills. Promoting SSO diversion from landfills to anaerobic digestion (AD) is predicated on SSO feedstock pretreatment to enhance the digestibility and conveyance of SSOs. This project, as funded by the Water Research Foundation, aims to comprehensively evaluate SSO pretreatment technologies with guidance from existing facilities to develop recommendations for SSO pre-treatment alternatives for utilities considering SSO diversion. The project has been divided into four tasks: 1. Task 1: Global Literature Review and Survey of Existing Technologies and Management Strategies 2. Task 2: Evaluation of Existing Technologies and Management Strategies 3. Task 3: Case Studies with a Wastewater Industry Focus 4. Task 4: SSO Pretreatment Analysis and Decision Tool This project provides guidance for utilities interested in SSO pre-treatment and co-digestion in order to: 1. Successfully build new or enhance existing SSO pretreatment and co-digestion programs, 2. Address challenges and opportunities involved with SSO pretreatment, 3. Identify SSO pretreatment requirements based on SSO feedstock quality and quantity, an 4. Determine capital and O&M costs and potential impacts on WRRFs. APPROACH Information pertaining to SSO pretreatment was gathered from literature sources including conference proceedings, project reports, journal articles, and manufacturer documentation in conjunction with questionaries from utility and vendor partners, as well as case studies from domestic and international facilities. Using a four-task approach, information has been distilled into a literature review, fact sheets, case studies, and a SSO pre-treatment guidance tool. Further, this information has been compiled into a PowerBI dashboard. The compatibility and effectiveness of multiple SSO pretreatment technologies were evaluated with information gathered from currently operating facilities which informed the development of SSO pretreatment selection workflows. These workflows were constructed based on contaminant properties such as size and type to distinguish appropriate pretreatment technology selection.
RESULTS AND FINDINGS
Task 1. Global Literature Review Task 1 focused on gathering information related to the application of SSO pretreatment prior to AD which was assembled in a literature review. Results from the literature review were organized by features and capabilities of unit operations and processes (UOPs). Physical UOPs were the most frequently implemented SSO pretreatment technologies used for both initial and polishing steps as shown in Figure 1. In addition, package units were found to be very attractive for utilities seeking multiple technologies in series for efficient removal of numerous contaminants. A thorough list of pretreatment technology vendors was also provided as a reference for utilities planning pretreatment installations.
Task 2. Existing Technologies and Management Strategies Evaluation Seventeen (17) utilities and technology providers, both in the US and abroad, were surveyed through the completion of a questionnaire inquiring about existing pretreatment facilities. The information gathered was summarized into factsheets (example shown in Figure 2) containing information such as process flow diagrams, facility details, lessons learned, and maintenance requirements. Major findings from Task 2 include: - Receiving pre-treated SSO is advantageous for controlling consistency and material quality. - Adequate storage should be provided at the receiving facility. - Removing contamination to the extent possible ensures that downstream equipment and digester(s) aren't adversely impacted by SSO. - Storing critical spare parts on site is recommended.
Task 3. Case Studies Results Task 3 results contain insight from seven case studies focused on SSO pretreatment in the wastewater industry. Case studies provided detailed information related to each utility such as mass balances, facility financial information, construction characteristics, and anticipated maintenance schedules. Unit cost curves have been developed for the SSO pretreatment facilities (example shown in Figure 3) to provide an estimate of construction cost, O&M cost, biogas revenue, tipping fees, and inert disposal costs as a function of wet ton of waste. Overall, increasing facility size had decreasing unit costs due to economies of scale.
Task 4. SSO Pretreatment Selection Guidance Much of the technology documentation accumulated through the literature review, database development, and case studies was instrumental in the development of multiple SSO pretreatment workflows to guide SSO pretreatment selection. Workflows created as part of Task 4 are structured by contaminant type, size, and physiochemical properties. For example, as shown in Figure 4, appropriate selection of metal and glass removal technologies is contingent on the material size and can be further distinguished by color, magnetism, mobility.
DISCUSSION AND BENEFITS
The collection of information provided in this study is vital for utilities considering SSO pretreatment by providing technology descriptions, financial information, process mass balances, and selection tools for utilities to functionally apply SSO pretreatment at existing or future anaerobic digestors. While previous studies have focused on AD optimization, there is limited information related to the nuances of SSO pretreatment operation and overall pretreatment effectiveness as discussed in this study. As facilities continue to push for more sustainable waste solutions, the application of SSO pretreatment technologies can be a cost-effective improvement in AD performance.

This project, as funded by the Water Research Foundation, aims to comprehensively evaluate SSO pretreatment technologies with guidance from existing facilities to develop recommendations for SSO pre-treatment alternatives for utilities considering SSO diversion. A comprehensive evaluation of SSO pretreatment technologies was provided in this study to demonstrate the compatibility and effectiveness of numerous pretreatment technologies as implemented in case studies worldwide.

SpeakerBlate, Micah

Presentation time

13:35:00

13:45:00

Session time

13:30:00

15:00:00

TopicIntermediate Level, Biosolids and Residuals, Energy Production, Conservation, and Management, Research and Innovation

Author(s)

Blate, Micah

Author(s)Micah Blate1; Mohammad Abu-Orf1; Derya Dursun1; Kelly Landry1; Conner Murray1; Nicole Kaiser2; Robert Sharp2

Author affiliation(s)Hazen and Sawyer1; Manhattan College2