Williams, Todd

Mr. Williams has a 43-year career in environmental engineering with operating and design experience and specific emphasis in residuals and biosolids management. Todd has supported dozens of biosolids and residuals management master plans in his career which include adaptive planning to manage emerging contaminants such as PFAS. Todd is an engineering graduate of Virginia Tech and previously served as the Chair of the Water Environment Federations Residuals and Biosolids Committee.

Titles from this speaker

Description: Biosolids Master Planning in Tulsa, Oklahoma to Develop a Sustainable Biosolids...

Biosolids Master Planning in Tulsa, Oklahoma to Develop a Sustainable Biosolids Management Program

Abstract

Biosolids Master Planning in Tulsa, Oklahoma to Develop a Sustainable Biosolids Management Program The Regional Metropolitan Utility Authority (RMUA) is responsible for the plant infrastructure as well as the operation and maintenance of the 16 million gallon per day (MGD) capacity Haikey Creek Wastewater Treatment Plant (HCWWTP) in Tulsa, Oklahoma. To evaluate the future needs for treating and handling biosolids generated at the HCWWTP, the RMUA authorized engineering development of a biosolids improvements facility plan and concept level design of needed facility upgrades. For the past 19 years, unstabilized biological sludge from the aeration process has been thickened and then hauled to the Tulsa Southside WWTP for treatment via anaerobic digestion and land application. However, this practice requires hauling of 9-10 tanker trucks a day to the City of Tulsa's Southside WWTP and requires significant coordination between the two plants. The goals of this study were to identify existing conditions, estimate future loadings (up to 24 MGD) , and evaluate cost-effective alternatives to upgrade the HCWWTP to a stand-alone facility, produce biosolids product that could be beneficially used, and define a solution that is not only within the RMUA budget constraints, but defensible (with no regrets) to RMUA and its two partner agencies, the Tulsa Municipal Utility Authority (TMUA) and Broken Arrow Municipal Authority (BAMA). The study provided an opportunity to not only investigate technologies for producing Class B or Class A biosolids for beneficial use, but also to consider adaptability to changing regulations and potential energy savings and reductions in carbon emissions. The following outlines the steps which were used to develop an updated solids management plan and concept level design for RMUA. 1.Existing and Future Conditions - This task included an evaluation of existing solids handling processes at the HCWWTP and the ability of the existing facilities to meet future projected loadings. Estimates of future quantities of solids production were made to determine appropriate sizing of solids management equipment in the near term (next 5 years) and into the future (20 years). This analysis was used to develop appropriate sizing criteria for all solids handling system components such that any deficits in capacity needs and the timing of equipment upgrades to eliminate those deficits were identified for future planning tasks. 2.Evaluation Criteria Development and Identification of Appropriate Technology Solutions -Through a workshop discussion with RMUA staff, the universe of technology alternatives was discussed with the goal of identifying potential biosolids management solutions and appropriate evaluation criteria consistent with RMUA goals and objectives were established. These criteria and potential technology options were defined in a workshop with RMUA stakeholders as well as engineering subject matter experts and the relative importance of these criteria determined. Fifteen biosolids management options as compared to the status quo were then identified in a collaborative process for consideration by the stakeholder team. The evaluation criteria previously developed was then applied against the potential technology solutions aimed at meeting RMUA goals. Figure 1 shows the result of the weighted scoring of these alternatives. At the conclusion of this criteria development and technology options identification, six potentially viable alternatives were selected by RMUA for further evaluation compared to status quo including: - Chemical-Thermal Hydrolysis - Mesophilic Anaerobic Digestion - Composting - Thermal Drying - Mesophilic Anaerobic Digestion plus Thermal Drying - Mesophilic Anaerobic Digestion, Thermal Drying plus Pyrolysis 3.Plant Simulation Evaluations - Existing whole plant simulation models for the HCWWTP were modified to analyze and evaluate the 7 alternatives identified to determine overall impacts on process performance, energy recovery and use of existing assets (tankages and equipment). Outputs of the simulations included overall energy balances, green-house gas emissions, and process performance compared to status quo. The outputs of this modeling exercise were then presented in a workshop with RMUA staff and used to further define the short-listed alternatives for further investigation and refinement. 4.Cost Evaluations - The simulation models formed the basis for conducting capital, O&M and life-cycle cost analysis of the 8 short-listed alternatives identified. Comparative cost evaluations were developed including vendor quotes for large equipment and cost estimating data from previous engineering project experience. Cost estimating tools were then used to compare capital, O&M and life-cycle costs for each alternative. These costs were then considered alongside the non-monetary evaluation criteria identified to develop a cost-benefit analysis. Figures 2&3 show the results of these cost and cost-benefit analyses. An interactive workshop was then held with RMUA stakeholders to fully vet the alternatives and determine three potential technology options for implementation. 5.Site Visits - The RMUA stakeholders then toured three representative technologies in Oklahoma including anaerobic digestion, thermal drying and composting. At the conclusion of the site visits, RMUA stakeholders agreed that while all three technologies could work for them, composting was the best choice due to simplicity of the process and production of a marketable product. 6.Implementation Planning - Implementation of the composting alternative was defined in terms of phasing, scheduling and budget planning to ensure the design and building of composting dewatering and composting facilities with the right capacity will be developed at the right time to meet the City's near-term and long-term needs. Through their engineering partner, City of Tulsa was able to apply for and secure grant funding from the USDA for 20 percent or$ 9.8 million of the total project cost (estimated at $48 million). Project Status One of the most interesting aspects of the project was that based on the previous biosolids management study done in 2014, preconceived solutions of anaerobic digestion and improved dewatering to then land apply biosolids cake was thought to be the solution that would be recommended. However, by revisiting potential solution options and redefining what criteria were most important, several different solutions were reconsidered. Ultimately, site visits conducted by RMUA Staff proved to be extremely helpful in the selection of the composting process that is proven, simple to operate and produces a biosolids product with multiple uses. This selection really paid off when grant funding became available that the compost production process proved to be qualified for, saving the RMUA nearly $10M in costs. This part of the story will be detailed in the paper and presentation. The Haikey Creek Wastewater Treatment Plant Biosolids Improvements Project has been approved and is in the design phase of a 10.2 dry ton per day capacity aerated static pile composting facility expandable to 15.3 dry tons per day in 2060. Major facility components include gravity thickener improvements, sludge storage, new centrifuge dewatering as well as a new covered aerated static pile facility. This case study will present details and results of the entire planning process which will provide planners, engineers, administrators, and owners with insight into the planning process used to select the right solution using specific owner driven criteria as well as costs to choose the right solution for their biosolids management needs.

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

SpeakerWilliams, Todd

Presentation time

08:30:00

09:00:00

Session time

08:30:00

11:15:00

SessionCase Studies & Lessons Learned

Session number27

Session locationOklahoma City Convention Center, Oklahoma City, Oklahoma

TopicCompost, Master Planning, Residuals

Author(s)

Williams, Todd

Author(s)T. Williams1, A. Romero1, T. Johnson1, L. Ostervold2, M. Vaughan3

Author affiliation(s)Jacobs 1; Jacobs 1; Jacobs 1; Black & Veatch 2; City of Tulsa 3;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Jun 2024

DOI10.2175/193864718825159427

Volume / Issue

Content sourceResiduals and Biosolids Conference

Word count14

Impact of Several Biosolids Stabilization Technologies on PFAS

Abstract

Abstract Summary It is well understood that conventional treatment approaches do not effectively remove PFAS from liquids or solids streams at wastewater treatment plants. Future regulatory enforcement of PFAS has varied state-to-state providing uncertainty for utilities as they plan for future process upgrades. To assist utilities and biosolids producers, several biosolids products were tested including dried biosolids, pyrolyzed dried biosolids and composts, all produced with non-industrially impacted biosolids to assess the concentration of PFAS compounds in the finished products and the ability of these processes to reduce and or remove PFAS compounds. The full paper will summarize findings from this study. Introduction Per- and Poly-Fluoroalkyl Substances (PFAS) are a large family of organic compounds, including more than 4,500 synthetic fluorinated organic chemicals used in commercial, consumer and industrial products since the 1940s. Conventional treatment methods do not efficiently remove PFAS which are resilient to degradation and tend to sequester to the treated solids produced and the resultant biosolids. In its most recent (2021) review of pollutants in biosolids, the US EPA identified eight PFAS in biosolids, and is undergoing a problem formulation process which will serve as the basis for determining whether regulation of PFOA and PFOS in biosolids is appropriate. If EPA determines that a regulation is appropriate (currently expected in 2024), biosolids producers will be required to meet certain standards. This potential outcome of EPA's review underscores the importance of understanding technical solutions available to treat PFAS in biosolids if required based on EPA's review process. Technical Content To assist utilities and biosolids producers to understand options available to them to mitigate potential PFAS contamination in biosolids, several biosolids products were tested including dried biosolids, pyrolyzed dried biosolids and composts, all produced with non-industrially impacted biosolids to assess the concentration of PFAS compounds in the finished products and the ability of these processes to reduce and or remove PFAS compounds. Samples of input and output solids, bulking agents and finished products were analyzed for 24 PFAS compounds utilizing Liquid Chromatography Tandem Mass Spectrometry (LC/MS/MS). The facilities tested include: three dried biosolids facilities, two pyrolyzed dried products including output solids, gas and oil, and six compost products. Figure 1 provides an overview of PFAS (PFOA, PFOS, and total PFAS) concentrations by sludge type and the impact of composting operations. This figure demonstrates the progression (and conversion) of the PFAS concentration from the various raw sludge types. In some cases, the type of bulking agent used (fresh yard waste, wood chips, or the amount of recycled bulking agent used) can impact the concentrations of various PFAS compounds in the final compost products. Depending on the sludge type, the composting process has shown to increase or decrease measured PFAS. The variability in the results suggest the presence of precursors in the raw sludge. Additional detail regarding these impacts will be provided in the full paper. Figure 2 summarizes reduction of PFAS compounds through thermal drying using a rotary kiln dryer, where a range of 25-75% reduction was observed (45% average reduction) through drying. Figures 3 and 4 summarize the impact of pyrolysis on PFAS degradation in undigested digested and digested sludges, respectively. In both cases, a significant reduction in PFAS compounds was observed through pyrolysis, with near non-detect PFAS concentrations in the biochar and between 85% and over 99% reduction of measurable PFAS was achieved on a mass basis of all outputs including biochar, biooil and pyrogas. This will be one of the first published results on the entire outputs from the pyrolysis of wastewater sludges. Paper and Presentation This paper and presentation will provide information regarding the measured concentrations of PFAS in wastewater solids, dried biosolids, pyrolyzed biosolids (including the resultant pygas) and biosolids based compost products. PFAS precursor analyte presence and concentrations in the input solids as well as the wastewater treatment process used to generate these products will also be presented. This information will be useful for those considering methods to reduce or eliminate PFAS in their own wastewater solids or other input wastewater solids at existing or planned biosolids management operations to ensure the lowest feasible PFAS concentrations in end products can be achieved. This presentation will help utility planners, operators, engineers, and administrators understand the nature of the PFAS issue in biosolids, how these compounds are introduced into biosolids, the rapidly changing regulatory landscape, and what technologies are being used to reduce or eliminate these compounds from wastewater biosolids products.

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

SpeakerWilliams, Todd

Presentation time

9:30:00

10:00:00

Session time

8:30:00

11:45:00

SessionSession 10: PFAS Challenges and Treatment

Session number10

Session locationCharlotte Convention Center, Charlotte, North Carolina, USA

TopicEmerging Issues (PFAS, Microplastics, Covid, etc.)

Author(s)

T. Williams

Author(s)T. Williams1, S. Grieco2, B. Bani3, 4,

Author affiliation(s)Jacobs1

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date May 2023

DOI10.2175/193864718825158798

Volume / Issue

Content sourceResiduals and Biosolids

Word count9

Description: Removal and Transformation of PFAS from Biosolids in a High Temperature Pyrolysis...

Removal and Transformation of PFAS from Biosolids in a High Temperature Pyrolysis System - A Bench Scale Evaluation

Abstract

Per- and Poly-Fluoroalkyl Substances (PFAS) are a large family of organic compounds, including more than 4,000 synthetic fluorinated organic chemicals used since the 1940s. PFAS have unique surfactant properties that make them repel both water and oil. Because of these properties, they have been used extensively in firefighting foams, surface coatings, and protectant formulations for consumer products, including paper and cardboard packaging products, carpets, leather products and clothing, construction materials, and nonstick coatings (ITRC, 2020). Manufacturers of these items often discharge to Water Resource Recovery Facilities (WRRFs). Landfill leachate discharge and household sewage are also common sources of PFAS in WRRF influent. Conventional WRRFs have proven to be relatively ineffective in removal of PFAS and discharge from WRRF is considered a major source of PFAS in the environment (Ahrens 2011, Chen et al., 2018). There is mounting evidence that continued exposure above specific levels of certain PFAS may lead to adverse health effects (USEPA 2016a, 2016b, ATSDR 2018a). PFAS concentrations in wastewater and sludge or biosolids are mass loading based. Long chain PFAS compounds discharged into WRRFs partition to the solids and end up in the resulting sludge or biosolids. The presence of PFAS in WRRF biosolids has raised a concern in the recent years for beneficial land application programs as PFAS could mobilize in soil, leach into run-off, infiltrate into groundwater or be taken up by biota (Lindstrom et al. 2011, Rich et al. 2015, Sepulvado et al. 2011). Within the PFAS family of compounds, perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are the two most common compounds and are a focus of Federal and State drinking water and environmental regulations. These compounds were commonly used in the manufacture of aqueous film forming foams (AFFF) for fighting aircraft fuel fires and other industrial and commercial products. In February 2019, the US EPA developed an action plan to limit human exposure to potentially harmful levels of PFAS in the environment. The short-term action plan includes testing for measurable PFAS and PFAS precursors in biosolids. The action plan was updated in February 2020 indicating that EPA is developing a risk assessment to better understand the potential public health and ecological risks associated specifically with PFOA and PFOS in land-applied biosolids. With mounting concern about the presence of PFAS in biosolids and the lack of specific guidance from the US EPA regarding the risks of these compounds within biosolids, some states have begun their own evaluations on this topic with suggested concentration limits of PFAS in biosolids used for land application. However, state regulatory agencies do not have a consistent approach to managing PFAS in biosolids. These concerns coupled with lack of consistent guidelines from the US EPA and state regulators has caused utilities to consider alternatives to eliminate the presence of PFAS in biosolids to minimize their risk exposure to potential future regulatory standards. As a result, technologies which can effectively destroy PFAS in biosolids based products are being investigated. One such technology is pyrolysis. Pyrolysis is the conversion or cracking of biomass or biosolids at high temperatures in the absence of oxygen. As most organics are thermally unstable, they can be split in a pyrolysis process by a combination of thermal cracking and condensation reactions into gaseous (pyrogas), liquid (bio-oil), and solid (biochar) fractions. With limited research available on the ability of pyrolysis to eliminate PFAS from biosolids and the fate of PFAS in the resulting effluents (solids, liquid, and air), there is a need to provide actual data for engineers and planners to evaluate as to the actual performance of the pyrolysis process with respect to PFAS reduction and fate. Jacobs and CharTech Solutions (CharTech) recently partnered to investigate the application of CharTech's High Temperature Pyrolysis Technology for biosolids management, and its efficacy in eliminating PFAS from the solid fraction. In addition, the transformation or elimination of PFAS compounds by measuring concentrations in the resultant bio-oil and pyrogas produced from the pyrolysis process were evaluated. This is one of the first analyses done using dried biosolids which captured PFAS data from the all output matrices including the resultant char, bio-oil and pyrogas fractions resulting from the pyrolysis of biosolids. Bench scale testing was performed in a continuously fed pyrolysis unit to compare the PFAS removal performance at 500 °C and 700 °C pyrolysis temperatures. Dried biosolids tested in the bench scale test were derived from un-stabilized waste activated sludge produced from two WRRFs operated by Jacobs. The solids were previously dewatered with belt filter presses to approximately 20 percent solids and subsequently dried in a batch thermal dryer fired with natural gas to evaporate water, resulting in a biosolids product that was approximately 93 percent solids. The dried biosolids material previously met Class A Exceptional Quality biosolids product status by achieving all pathogen and vector-attraction reduction requirements, as well as meeting the concentration limits of heavy metals according to the U.S. Environmental Protection Agency's (EPA) 40 Code of Federal Regulations (CFR) Part 503 Rule. Twenty eight of the most commonly measured PFAS compounds were analyzed in the feed biosolids, biochar, bio-oil and 31 PFAS compounds were analyzed in the pyrogas. Only six PFAS compounds (10:2 Fluorotelomer sulfonic acid, PFOS, N-Et PFO sulfonamidoacetic acid, N-Me PFO sulfonamidoacetic acid, Perfluorohexanoic acid, and Perfluoroundecanoic acid) were measured above the detection limits in the feed biosolids. Three PFAS compounds were detected in the biochar at the 500 °C pyrolysis temperature (Perfluorohexane sulfonic acid, Perfluorohexanoic acid, Perfluorooctanoic acid), all at less than 0.5 ppb (dry weight). No PFAS compounds were detected in biochar at the 700 °C pyrolysis temperature. PFOS was measured at 26.6 ppb in the feed biosolids but not detected in the biochar, bio-oil or pyrogas at either pyrolysis temperature. Although not detected in the dried biosolids, PFOA was detected at very low concentrations in biochar and pyrogas indicating a lack of complete destruction and/or transformation of precursor compounds during pyrolysis. Higher concentration of Perfluorohexanoic acid (PFHxA) in pyrogas at 500 °C compared to 700 °C was observed, suggesting greater destruction of PFHxA at a higher temperature. To better understand the PFAS fate through the pyrolysis process, mass balance analysis on biochar, bio-oil and pyrogas streams were conducted and removals of PFAS were estimated. The result of mass balance analysis indicated a total measured PFAS mass removal of 84.4% and 95.6% for 500 °C and 700 °C, respectively for all the PFAS tested in this study. This paper will describe in detail the testing apparatus and procedures used and provide a full description of the results measured. The information will be useful for engineers, planners, scientists, utilities, regulators and others interested in the evaluation of pyrolysis as a potential biosolids management alternative to minimize PFAS in biosolids.

The following conference paper was presented at Residuals and Biosolids 2021: A Virtual Event, May 11-13, 2021.

SpeakerWilliams, Todd

Presentation time

13:40:00

14:00:00

Session time

13:00:00

14:00:00

SessionPFAS and Contaminants of Concern in Biosolids

Session number1

Session locationSimu-Live

TopicBiosolids, Microconstituents, pyrolysis