Ross, John

John Ross is with Brown and Caldwell, based in Massachusetts.

Titles from this speaker

Managing Biosolids in Maine: Challenges and Potential Solutions

Abstract

Background Portland Water District (PWD) has four wastewater treatment facilities (WWTFs) with a capacity of more than 25 million gallons per day. Two of the four facilities - East End and Westbrook - process most of the solids in the system and were the focus of PWD's comprehensive approach to assess the current solids system and develop a strategic plan that outlines the necessary upgrades, process modifications, and state-of-good-repair projects that PWD should undertake during the next 20-year planning period. PWD began contemplating this planning effort not only due to aging infrastructure, but rather due to increasing concern over lack of biosolids management options and rising public concern around per- and polyfluoroalkyl substances (PFAS) in biosolids. Throughout New England, decreased biosolids management capacity has been a rising concern. Much of the region relies upon landfills and regional incinerators, but beneficial use (land application) has served as a reliable, sustainable option for a number of utilities. In Maine, land application had been an accepted practice, with good market understanding of the benefits of biosolids, including biosolids based compost and thermally dried products. Concerns over PFAS in wastewater residuals, or solids, prompted legislative action to prohibit land application of treated wastewater solids (biosolids) and products containing biosolids in Maine (LD 1911 [An Act to Prohibit the Contamination of Clean Soils with So-Called Forever Chemicals]). The Governor signed this bill in April 2022, and it is currently in effect as Public Law 2021 Chapter 641. This law leaves Maine wastewater utilities with landfill as the only option for solids management within the state-and few, costly options outside the state. Instate wastewater solids landfilling became more challenging with the passing of solid waste bill, LD 1639 (An Act To Protect the Health and Welfare of Maine Communities and Reduce Harmful Solid Waste) in April 2022, and enacted February 1, 2023. This bill restricts the importation of out-of-state solid waste for processing in the state of Maine. Dewatered wastewater solids cake is considered a 'wet waste' by landfill operators and is typically mixed with bulking agents at landfills to avoid stability issues. Out-of-state solid waste (e.g., oversized bulky waste and construction and demolition debris) was one of the main sources of bulking agents for stabilizing wastewater solids. When the availability of these bulking agents decreased, the landfill operators handling most of the biosolids disposal in the state reported they needed to consequently reduce the amount of wastewater solids they accept. This left many utilities scrambling for alternatives, including costly long-distance hauling to Canada. Despite a two-year reprieve to LD 1639 (via LD 718, An Act to Facilitate the Management of Wastewater Treatment Plant Sludge at the State-owned Juniper Ridge Landfill), wastewater utilities in Maine, including Portland Water District (PWD), are still restricted to landfilling instate in the short-term, and following the two-year reprieve will face severe challenges in the long-term. Methodology This project was completed to define the technical, economic, and programmatic considerations for implementing a regional anaerobic digestion, drying, and thermal treatment biosolids processing facility. These technologies were selected for consideration for their following attributes: - Anaerobic Digestion. Anaerobic digestion biologically degrades solids, reducing their mass by 40-50 percent and generating energy-rich biogas. Anaerobic digestion can process a wide variety of liquid organic wastes, including food and beverage processing wastes and fats, oils, and grease waste. Anaerobic digestion and biogas utilization offer substantial opportunities for greenhouse gas reduction at a WWTF and for the region when processing imported organic waste. Anaerobic digestion can also treat solids to United States Environmental Protection Agency (USEPA) requirements for Class B or A stabilization and improves downstream processing by improving and homogenizing solids quantities and quality. - Thermal Drying. Thermal drying removes nearly all the entrained water in dewatered solids, reducing solids mass by 4 to 5 times. This reduces the amount of solids needing to be hauled and can remedy capacity and structural limitations associated with landfilling of dewatered solids. Thermal drying can also meet USEPA Class A stabilization requirements, which provides nearly unrestricted beneficial reuse opportunities in other states. - High Temperature Thermal Processing. Thermal processing submits solids to high temperatures for further mass reduction and treatment of emerging contaminants such as PFAS. This has traditionally been performed by sewage sludge incineration (SSI), which oxidizes all solids to an ash. However, SSI air permitting regulations have become especially onerous and make SSI adoption in New England unlikely today. Pyrolysis and gasification are emerging, non-incineration thermal processes that employ high temperatures at oxygen free or starved conditions to generate a carbon-dense beneficial reuse product called biochar and a gas stream with an appreciable energy value. The technology is still in a developmental stage with one commercial biosolids pyrolysis facility in operation in the US at Silicon Valley, CA. In 2020, the USEPA found the Silicon Valley pyrolysis system removed PFAS from biochar to below reportable levels (Thoma et al., 2021). BC, with Silicon Valley Clean Water and the Water Environment Federation are scheduled to perform a PFAS air emissions test early 2024 to evaluate PFAS destruction in the gas phase. The Silicon Valley pyrolysis system uses a thermal oxidizer for emissions control and heat recovery and previous work by the USEPA demonstrated thermal oxidation as suitable for designation as a Best Available Control Technology for PFAS and capable of meeting permitted PFAS destruction criteria (Barr, 2022; Beahm, 2019; Focus Environmental Inc., 2020). While pyrolysis and gasification require solids be dewatered and dried for processing, a new class of thermal processes is also emerging called hydrothermal treatment, that treat solids in a liquid, slurry form at high temperatures. Super critical water oxidation is one example where all organics (including organoflourines such as PFAS) are intended for oxidation within a flow-through reactor. Hydrothermal carbonization and hydrothermal liquefaction use heat without an oxidant to refine the solids into solid and liquid biofuels, respectively. Conclusions The BC and PWD team completed the following outreach and assessment tasks to identify and compare current market offerings for the solids processing technologies mentioned above. The investigation included assessment of commercially available equipment and overall project delivery and operation under the following tasks. - Request for Information (RFI): BC developed and issued an RFI digestion, drying, and thermal processing system suppliers. The goal of issuing this RFI was to identify interested technology and/or solution providers and to compare current commercial offerings based on lifecycle cost and key non-economic criteria. - Technology Summit: Responders to the RFI could participate in a two-day in-person and virtual technology summit, in which each participant had 20 minutes to present information about their technology. These presentations were recorded and are available on the PWD website. - RFI Submission Review: Each submission was evaluated based upon set criteria, established in the RFI document. Table 1 summarizes the scores for the highest ranked submissions. - Alternative Evaluation: Based on the top three ranked system supplier offerings/technologies, facility concept level designs were developed for a business case evaluation (BCE). The Alternatives BCE evaluated three onsite and three regional technology alternatives. These alternatives are summarized along with their BCEs in Table 2. - Recommendations: The RFI submissions and BCEs enabled the PWD and BC team to identify a potential phased path forward for PWD. The purpose of this report is to summarize and describe the methodology BC employed, as well as the economic and noneconomic findings, from the evaluation of a regional, offsite biosolids processing facility. Ultimately, the goal is to characterize the economic viability and noneconomic attributes to assist PWD in determining a path forward to manage

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

SpeakerBrower, William

Presentation time

14:00:00

14:30:00

Session time

13:30:00

15:00:00

SessionOutreach Updates: From State to Regional Solutions

Session number07

Session locationOklahoma City Convention Center, Oklahoma City, Oklahoma

TopicBiosolids Management Planning, business case evaluation, Regionalization

Author(s)

Firmin, Scott

Author(s)S. Firmin1, W. Brower2, T. Chouinard2, J. Ross2, N. Sierra2

Author affiliation(s)Portland Water District 1; Brown and Caldwell 2; Brown and Caldwell 2; Brown and Caldwell 2; Brown and Caldwell 2;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Jun 2024

DOI10.2175/193864718825159464

Volume / Issue

Content sourceResiduals and Biosolids Conference

Word count9

PFAS Assessment of a Rotary Drum Dryer

Abstract

Introduction Biosolids drying is gaining interest as a volume reduction strategy in regions where biosolids management outlets are becoming increasingly constrained due to concerns over per- and polyfluoroalkyl substances (PFAS). However, no studies as of yet have been conducted on the fate of PFAS through a thermal dryer system. Synagro partnered with Brown and Caldwell to conduct a PFAS mass balance through a centrifuge dewatering and rotary drum dryer facility to evaluate the fate of PFAS through the system and assess potential points of PFAS transfer to the environment. Methodology A three-day PFAS sampling event was conducted the week of April 17, 2023. Process samples were taken at all inputs and outputs to the system with composite sampling over a four hour period each day. An overview of the dewatering and dryer system and PFAS sampling points is provided in Figure 1. The dewatering and dryer system was operated at roughly 2,300 dry pounds of total solids per hour for the duration of the test. Gas-phase sampling was conducted by a commercial stack sampler using an OTM-45 PFAS sampling train at the stack and prior to the regenerative thermal oxidizer emissions (RTO) control device. In addition, a fourth run was conducted on the final day of the week when the dryer was down, but the scrubber was kept in operation to evaluate if PFAS were released from cooling water in the scrubber. The PFAS data was received in October 2023 and are currently being evaluated using the data quality analysis plan developed under the Brown and Caldwell lead Water Research Foundation Tailored Collaboration program project (WRF 5111). Results and Discussion PFAS sampling data is under review and will be available for detailed comparison by 2024 WEF RBC. An initial review of preliminary findings is provided in Tables 1, 2 and 3 attached with the following findings below. - Individual PFAS were transferred from biosolids to the gas phase at a transfer rate of 50% to 92% through the dryer. - No widespread trend of PFAS accumulation in the scrubber water was observed. Individual PFAS showed a modest increase from 10% to 20%. - Eighteen individual PFAS were detected in the gas phase from the dryer, prior to treatment in the RTO, - HFPO-DA and trace amounts of three PFAS were detected in the emissions from the RTO. Field QC and prior study findings indicate HFPO-DA detection may be due to contamination/interference, more work is required to verify. - More work required to refine liquid sludge analysis and develop system-wide PFAS mass balance. Conclusions This study is the first to present data demonstrating PFAS transfer from solids phase to the process air during thermal drying of biosolids. The data suggests the thermal oxidizer is capable of providing effective PFAS destruction or removal from the gas phase. More analysis will be conducted to present PFAS partitioning through the dewatering system and evaluate the aggregate PFAS mass balance through the dewatering and drying process.

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

Presentation time

10:45:00

11:15:00

Session time

10:45:00

11:45:00

SessionDryer

Session number15

Session locationOklahoma City Convention Center, Oklahoma City, Oklahoma

TopicDrying, PFAS

Author(s)

Ross, John

Author(s)J. Ross1, A. Seidel1, L. Winchell1, M. Wells2, D. Song 3,

Author affiliation(s)Brown and Caldwell 1; Brown and Caldwell 1; Brown and Caldwell 1; EnviroChem Services 2; Synagro Technologies, Inc.3;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Jun 2024

DOI10.2175/193864718825159466

Volume / Issue

Content sourceResiduals and Biosolids Conference

Word count8

Description: PFAS Study Updates: Sewage Sludge Incineration (WRF #5111) and Biosolids Pyrolysis...

PFAS Study Updates: Sewage Sludge Incineration (WRF #5111) and Biosolids Pyrolysis with Thermal Oxidation (WEF)

Abstract

This presentation provides an update on the progress of two PFAS fate studies through high-temperature biosolids processing systems. PFAS testing at two full-scale sewage sludge incinerators was recently completed under Water Research Foundation Project #5111 and results are expected for publication at the end of 2023. Preliminary PFAS sampling was conducted at the Silicon Valley Clean Water biosolids pyrolysis system and a lab-scale unit commissioned to mimic its operating parameters under a Water Environment Federation collaborative research project. Formal PFAS sampling is expected to occur this summer for the lab-scale unit and early 2024 for the full-scale pyrolysis system. This presentation presents several insights into test plan development and the status of analytical tools available to characterize the fate of PFAS through these systems. Key considerations include identification of relevant operating parameters and emission control devices for process technologies, limitations in reporting limits for gross organoflourine assessments, and recommended best practices for reporting PFAS detection and destruction and removal efficiency data.

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

SpeakerRoss, John

Presentation time

10:45:00

11:45:00

Session time

10:45:00

11:45:00

SessionSession 01: Impacts of Thermal Processes on PFAS - Updates from Water Research Foundation Projects

Session number1

Session locationCharlotte Convention Center, Charlotte, North Carolina, USA

Author(s)

J. Ross

Author(s)J. Ross1, L. Winchell2, M. Wells3, D. Westerman4, D. Knappe5, X. Fonoll Almansa6, J. Norton7,

Author affiliation(s)Brown and Caldwell1; EnviroChem Services2; North Carolina State University3; Great Lakes Water Authority4

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date May 2023

DOI10.2175/193864718825158818

Volume / Issue

Content sourceResiduals and Biosolids

Word count16

Pyrolyis Gas Thermal Oxidation: PFAS and Emissions Control

Abstract

Introduction Biosolids pyrolysis and gasification are gaining interest as a means to remove per- and polyfluoroalkyl substances (PFAS) from biosolids, however PFAS destruction has yet to be proven from the gas phase emissions. In 2020, the USEPA demonstrated that PFAS were removed to below reporting limits in biochar, the solid phase residual product from the Silicon Valley Clean Water (SVCW) biosolids pyrolysis system, but analytical techniques had not matured at the time for gas phase analysis (Thoma et al., 2021). Later bench scale studies showed that appreciable amounts of PFAS could be transferred from biochar to the gas phase at typical pyrolysis temperatures (500°-700°C) (McNamara et al., 2023; Williams et al., 2021). Pyrolysis gas contains an appreciable energy density and can be combusted for energy recovery and the industry has long postulated that gas-phase PFAS would be destroyed in the gas phase when combusted (Winchell et al., 2022). However, no studies had been conducted to date to demonstrate the extent of destruction. This presentation presents results from a Water Environment Federation (WEF) research study lead by Brown and Caldwell with five utility and industry partners to develop a bench-scale biosolids pyrolysis and thermal oxidation laboratory scale reactor to evaluate PFAS inputs and outputs, including flue gas emissions from the pyrolysis gas thermal oxidizer. The lab-scale reactor was created in partnership with Western University and BioForceTech, the pyrolysis system supplier for SVCW, to mimic the pyrolysis and thermal oxidation parameters from the full-scale installation. This presentation provides results from the study and lessons learned from operational issues and proposed mitigation steps for thermal oxidation at full-scale. Methodology The bench scale biosolids pyrolysis and thermal oxidation system were manufactured and commissioned by Western University over a twelve-month period starting Spring of 2022. The thermal oxidizer was configured by installing a forced air gas burner in a steel-lined combustion chamber. The burner and combustion chamber were configured with a propane pilot system that ignited the pyrolysis gas mixture, creating a self-sufficient flame when pyrolysis gas is available. The chamber was configured to provide sufficient residence time and turbulence to match the SVCW system parameters (1,000°C at two seconds). Once the system was found to meet key performance requirements the PFAS sampling event was conducted May 2023. Dried biosolids from SVCW were processed in the lab-scale biosolids pyrolysis and thermal oxidation system over three operating days for a continuous four-hour sampling campaign each operating day. Biosolids were loaded at a rate of 15 grams per minute at a solids residence time of 20 minutes and processed at a pyrolysis reactor temperature of 620°C. PFAS were analyzed in the biosolids, biochar and gas phase extracts by Eurofins. Gas-phase sampling was conducted by a commercial stack sampler, Ortech, using a modified OTM-45 PFAS sampling train. The PFAS data was received in August and September 2023 and are currently being evaluated using the data quality analysis plan developed under the Brown and Caldwell lead Water Research Foundation Tailored Collaboration program project (WRF 5111). Results and Discussion PFAS sampling data is under review and will be available for detailed comparison by 2024 WEF RBC. An initial review of preliminary findings and their comparison to a 2019 BioForceTech study is provided below. - No clear trend was observed between PFAS in the dewatered and dried biosolids. A wide range of variability in PFAS concentrations was observed indicating potential PFAS transformation in the dryer, some PFAS transfer to gas-phase, or sampling variability. - Except for PFBA at 0.7 ng/g, PFAS were below reporting limits in biochar. The reporting limit for the 2023 data was 0.4 ng/g, an order of magnitude lower than the 2-4 ng/g reporting limits available in 2019. - The loading for each PFAS to the bench-scale system ranged from 0.1 - 15 ng per second and the individual PFAS emissions rates in the flue gas ranged from 0.0001 - 0.008 ng per second, indicating individual destruction and removal efficiencies (DRE) will generally exceed 99% for PFAS in the thermal oxidizer flue gas. Conclusions This study is the first to demonstrate PFAS destruction and removal from combustion of biosolids pyrolysis gas. This data can support PFAS air permitting from biosolids pyrolysis projects under consideration by state permitting agencies such as Maine Department of Environmental Protection. While the study demonstrates the efficacy of thermal oxidation for PFAS treatment at bench scale, several lessons learned have been identified from operational issues at the full scale SVCW pyrolysis system that should be considered before widespread adoption. The main issue faced by SVCW is excessive dust from the pyrolysis reactor transferred into the combustion chamber, coating the interior of the burner and chamber. This requires a regular shutdown and cleaning cycle that takes two to three days for cooling, cleaning and reheating. This presentation will provide insights gained into dust creation and mitigation measures under consideration by SVCW and BioForceTech to improve operational uptime.

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

SpeakerRoss, John

Presentation time

13:30:00

14:00:00

Session time

13:30:00

15:00:00

SessionCarbonization

Session number19

Session locationOklahoma City Convention Center, Oklahoma City, Oklahoma

TopicPFAS, pyrolysis

Author(s)

Ross, John

Author(s)J. Ross1, L. Winchell1, M. Romero1, F. Kakar1, A. Miot2, J. Norton3, M. Magruder4, K. Bell1

Author affiliation(s)Brown and Caldwell 1; Brown and Caldwell 1; Brown and Caldwell 1; Brown & Caldwell 1; Silicon Valley Clean Water 2; Great Lakes Water Authority 3; Milwaukee Metropolitan Sewerage District 4; Brown and Caldwell 1;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Jun 2024

DOI10.2175/193864718825159452

Volume / Issue

Content sourceResiduals and Biosolids Conference

Word count9

Working Towards a Sustainable Outlet for Maine Biosolids through a Regional Solution

Abstract

Background Throughout New England, decreased biosolids management capacity has been a rising concern. Much of the region relies upon landfills and incinerators, but beneficial use has served as a reliable option for a number of utilities, including in Maine. Concerns over PFAS prompted legislative action to prohibit land application in Maine. This law leaves wastewater utilities with landfill as the only option for solids management in the state. Landfilling has gotten more challenging with limited capacity and adoption of additional laws impacting the availability of bulking agents. A company has been working with the regulators in Maine and individual utilities, including the Portland Water District (PWD), to explore approaches to alleviating some of these challenges. The Maine Department of Environmental Protection (DEP) contracted to evaluate the current situation for biosolids management in the state and make concrete recommendations for change. PWD and the company worked together to determine the feasibility of onsite and offsite processing technologies. The technology evaluation for Maine DEP and PWD focused on digestion, drying, and thermal treatment technologies. These technologies were selected for consideration for their following attributes, among others: (1) Anaerobic Digestion. Biologically degrades solids, reducing their mass and generating energy-rich biogas. (2) Thermal Drying. Removes nearly all the entrained water in dewatered solids. This reduces the amount of solids to manage and can remedy capacity and structural limitations at landfills. (3) High Temperature Thermal Processing. Submits solids to high temperatures for further mass reduction and treatment of emerging contaminants such as PFAS. Pyrolysis and gasification are emerging, non-incineration thermal processes that employ high temperatures to generate a carbon-dense beneficial reuse product or an ash and a gas stream with an appreciable energy value. Hydrothermal treatment technologies were also considered-including super critical water oxidation and hydrothermal carbonization/liquefaction. Objectives This paper will detail the specific challenges facing biosolids management in the state (which echo the situation in many other parts of the country) and proposed 'levers' for the state government to address concerns. The situation will be further elucidated by looking in detail at the realities facing PWD and options available to the utility. Status The study for Maine DEP recently has been completed so final results will be presented. The company continues to work on refinements with PWD, but the main analysis has been completed. Methodology The company evaluated public data sources and DEP records to determine the amount of biosolids generated and the amount going to different end use locations. A questionnaire was sent to landfill operators to estimate future capacity for biosolids and barriers to landfills accepting biosolids. Questionnaires were also sent to organizations with interest in developing regional solutions and to providers of technology purported to reduce PFAS. To provide a guide for utilities throughout Maine, lifecycle cost analysis was performed on promising technology approaches at different scales using representative costs for the state. For PWD's specific situation, the team completed the following outreach and assessment tasks to identify and compare current market offerings.

*Request for Information (RFI): BC developed and issued an RFI for technology suppliers. The goal was to identify interested providers and to compare commercial offerings based on lifecycle cost and non-economic criteria.

*Technology Summit: Responders to the RFI could participate in a two-day in-person and virtual technology summit, in which each participant could present information about their technology.

*RFI Submission Review: Each submission was evaluated based upon set criteria.

*Alternative Evaluation: Based on the top three ranked onsite and offsite system supplier offerings, concept level designs were developed for a business case evaluation (BCE). Findings The company projected capacity within the state to manage biosolids; under certain scenarios capacity would be greatly exceeded by the amount of biosolids generated in as little as five years (see Figure 1). The company developed a range of recommendations for Maine government, including addressing limits on bulking agent availability at landfills, pushing for landfill expansions, funding pilots of PFAS treatment technologies, providing grants for volume reduction and dryer projects, and making changes to state regulations. The results of the BCE for PWD are shown in Figure 2, with the twenty-year net-present cost broken out by capital and operations and maintenance costs. The RFI submissions and BCEs enabled the team to identify a potential phased path forward for PWD that will address near term solids needs at the plant while continuing to explore regional processing options. Significance The challenges facing Maine are not unique to the state. The recommendations for Maine are transferable to other parts of the country. And many utilities around the country are looking at the same technologies-digestion, drying, thermal treatment-as approaches that reduce exposure to these challenges, so the results of the BCE for PWD will be of interest to many around the country

This paper details the specific challenges facing biosolids management in Maine (which echo the situation in many other parts of the country) and proposed 'levers' for the state government to address concerns. The situation is further elucidated by looking in detail at the realities facing the Portland Water District and options available to the utility.

SpeakerBrower, William

Presentation time

15:30:00

16:00:00

Session time

15:30:00

17:00:00

SessionManaging Biosolids for Tomorrow: Infinite Resources, Finite Uses

Session number218

Session locationRoom 253

TopicBiosolids and Residuals, Circular Water Economy, Energy Production, Conservation, and Management, Intermediate Level, Public Communication and Outreach

Author(s)