Allen, Shayla

Shayla is a detailed design engineer with a focus on developing and designing decarbonization solutions, particularly for the beneficial use of...

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About Allen, Shayla

Shayla is a detailed design engineer with a focus on developing and designing decarbonization solutions, particularly for the beneficial use of biogas at wastewater treatment facilities and landfills. She has develops sophisticated models to analyze and compare several decarbonization solutions using metrics such as annualized cost, capital cost, net kilowatt (kW) or diesel gallon equivalent (DGE) production, and greenhouse gas (GHG) emission reduction. These factors assist in developing a quantitative framework to better understand the effects of each alternative solution.

Allen, Shayla

Titles from this speaker

Coming Full Circle: Diverted MSW Organics to RNG Fuel for Refuse Trucks in Mesa, AZ

Abstract

As anaerobic co-digestion of municipal wastewater with food waste and fats, oils, and grease (FOG) becomes more widely implemented, developing a understanding of the effects co-digestion will have on the system, as well as developing a comprehensive investigation into the potential benefits - financial and environmental - is crucial to determining whether implementation will be advantageous. In collaboration with the Arizona State University Biodesign Swette Center for Environmental Biotechnology, several limits of digestion were developed and tested during bench scale digestion study. The bench scale study sets the precedence for the dynamic model; as well as pushed the limits to better understand the limits, indicators, and operational challenges of co-digesting commercial food waste and fats, oils and grease (FOG). The presented case study illustrates the use of dynamic modelling to evaluate several scenarios with variable quality of commercial food waste and FOG; quantity of waste a digestion system is feasibly able to accept; and the potential monetary and environmental benefits under various different biogas end uses. Based on modelling results, accepting 44 tons/day of unprocessed food waste and 10,000 gallons/day of unprocessed FOG can increase biogas production from 130 to 280 scfm. Compared to beneficial biogas end uses such as cogeneration, for the WRP it was both financially and environmentally advantageous to upgrade the biogas to compressed natural gas for the City’s existing compressed natural gas (CNG) vehicle fleet.

SpeakerAllen, Shayla

Presentation time

16:10:00

16:30:00

Session time

15:30:00

16:30:00

SessionRenewable Natural Gas: Innovations and Policy

Session number214

TopicBiosolids and Residuals, Energy Production, Conservation, and Management, Research and Innovation

Author(s)

S. AllenE. Auerbach

Author(s)S. Allen1; E. Auerbach1;

Author affiliation(s)Arcadis, NY1

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2020

DOI10.2175/193864718825157837

Volume / Issue

Content sourceWEFTEC

Word count16

Description: Grappling with the Biogas Regulatory Reform Rule -- How RNG Projects are Responding...

Grappling with the Biogas Regulatory Reform Rule -- How RNG Projects are Responding to the Recent Shake Up from the EPA

Abstract

In June 2023 the EPA passed the Biogas Regulatory Reform Rule, also referred to as BRRR throughout the biogas industry. The BRRR constitutes new set of requirements for registering biogas to Renewable Natural Gas (RNG) projects seeking to obtain RINs through the federal Renewable Fuel Standard Program. In practical terms the BRRR will bring about significant changes for planned, in-construction, and operational RNG assets. One of the major issues cited amongst RNG practitioners is the lack of clarity in the rules around the technical aspects of the regulation. This paper lays out some of the major aspects of BRRR relevant to Biogas Producers (i.e. WRRFs) and provides the latest clarity available from EPA decision making, as well as several case studies of RNG projects taking steps for compliance under the BRRR. Some of the major relevant aspects of the BRRR include: - Requiring each individual entity within the RNG supply chain to be separately registered with the EPA and undergo Quality Assurance Protocols (QAPs). - Requiring all existing and in-construction projects to register by specific timelines to be granted more lenient compliance under Alternative Measurement Protocols (AMPs). - Requiring flow metering equipment for biogas before upgrading to comply with specific metering technical specifications laid out 40 CFR 80.155(a)(1). - Requiring Btu measurement of biogas before upgrading to be measured with independent, dedicated Gas Chromatography (GC) equipment meeting technical specifications laid out 40 CFR 80.155(a)(2). - Providing a pathway for 'mixed digestion' in which a digester treating a mix of municipal sludge and imported food waste can retain a significant portion of D3 RIN classification. TIMELINES As shown in Figure 1, there are major timelines for various types of RNG projects to file registration, to file Alternative Measurement Protocols (AMPs), and receipt of approval by the EPA. Some of the major deadlines and time thresholds include: - Apr 1, 2024 -- window opens for legacy and in-construction projects to file registration allowing compliance with the old rules and AMPs for technical equipment compliance. - July 1, 2024 -- RNG projects must have begun construction by this date to be eligible for in-construction status when consideration for granting of AMPs. - Oct 1, 2024 -- window closes for legacy projects to file registration and AMPs. - Jan 1, 2025 -- EPA to issue decisions on AMPs filed by the Oct 2024 deadline and all legacy projects must have approved registration. This abstract is being written in Oct 2024 just as existing projects have reached the deadline for filing AMPs, with official decisions due back on Jan 2025. At the time of presentation of this paper, there should be more technical clarity available from the EPA based on the decisions rendered in response to these AMPs. BIOGAS PRODUCERS One of the fundamental shifts brought about the BRRR is a requirement for each individual entity within the RIN supply chain to have registration and compliance responsibilities. This new paradigm with each defined entity is shown in Figure 2. It should be noted that 'Biogas Producers' which include municipal WRRFs are defined entities within the supply chain. This is a departure from the old framework in which a single entity, typically a commercial developer or broker, was the sole pathway registrant. This change was intended to enhance transparency and reduce data manipulation within the RIN ecosystem. In practical terms, it means that WRRFs will be required to jump through more hoops to participate in biogas to RNG projects. New activities will include joining data exchange platforms, conducting EPA compliant record keeping, and being subject to quality assurance audits. BIOGAS MEASUREMENT The most direct impact on those designing and constructing RNG projects are the new BRRR technical requirements on biogas measurement, which includes both flow rate and Btu content of 'Biogas' as defined by the EPA. This is also the area in which the most technical clarification is still outstanding. The EPA defines biogas as a gas product that is: 1.At least 52% methane 2.Has not been treated or refined to the extent that is contains 75% methane or greater This has raised many yet unresolved concerns about the practical definition of biogas that will ultimately be accepted by the EPA. For example, there is ambiguity as to whether new required measurements of 'biogas' can occur after treatment steps like H2S removal, compression, moisture removal, and/or siloxane removal. Constructing biogas measurement equipment further upstream in the biogas train has a higher likelihood of meeting EPA biogas definitions but also creates more difficulties in measuring accurately and keeping measuring equipment from degrading. - Filing of AMPs -- legacy or in-construction RNG projects can avoid letter of the law technology compliance if they can demonstrate 'high installation costs' or 'physical difficulty' installing the new equipment. This is done by filing an AMP to demonstrate how alternative equipment to be used meets or exceeds requirements stated in the BRRR. -Metering -- new requirements were intended to increase granularity and timing of data collection. In practice, all biogas meters must comply with standards called out in 40 CFR 80.155 which preclude most biogas metering technology currently used in the industry. As a result, many meter manufacturers have submitted AMPs to get meters approved as alternate technologies. Facilities will also need to submit AMPs to prove they are using acceptable metering technology. A list of currently approved metering AMPs are shown in Table 1. - BTU Measurement -- this is perhaps the most challenging and most ambiguous technical requirement. The rule calls for separate and dedicated GC equipment to continuously measure 'biogas', with continuous measurements defined as once every 15 seconds. Very few, if any projects have provisions for raw biogas GC meters, and there are significant cost and practicality constraints for adding them, especially if 'biogas' cannot be refined to remove corrosive contaminants like H2S and moisture. No clarity is yet available on what will be accepted via AMPs on this item, but some direction is expected via the Jan 2025 responses to AMPs filed for legacy projects. MIXED DIGESTION In a tidbit of good news related to the BRRR, there was a new protocol set forth to allow for 'mixed digestion' which refers to municipal sludge digester that treat predominantly sludge but also import a portion of organic waste such as FOG or manufactured food slurry. Under old frameworks these digesters would be precluded from receiving D3 RINs despite the fact that the majority of their feedstock is cellulosic. Under new rules mixed digesters treating a majority of sludge have the following options to retain D3 RINs: - Accept 25% D3 RINs and 75% D5 RINs based on very conservative analytical derivations of biogas yields per new EPA standards. - Development of a 'baseline' condition for biogas production from only sludge, and that baseline will determine the ceiling amount of D3 RINs that can be generated, with the remainder being counted as D5. As of the writing of this abstract, no project has successfully been registered under this new mixed digester standard. This means many technical aspects of this rule are up for interpretation, especially in regards to requirements for setting baselines. The presentation will elaborate on any recent clarity brought forth on this item. CASE STUDIES Two case studies will be presented, both which are biogas to RNG projects considered to be 'in-construction' by EPA definitions. The paper will present actions taken and available results to bring these projects in compliance with BRRR. City of Mesa, AZ -- 300 scfm (nameplate) triple mass membrane RNG system slated for startup and commissioning in November 2024. Capital Region Water, Harrisburg, PA -- 400 scfm (nameplate) triple mass membrane RNG system slated for startup and commissioning in October 2025.

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

SpeakerAllen, Shayla

Presentation time

10:35:00

10:55:00

Session time

10:15:00

11:45:00

SessionAdvancing Biogas and RNG: Innovations and Regulatory Challenges

Session number26

Session locationBaltimore Convention Center, Baltimore, Maryland, USA

TopicAerobic Digestion, Alternative Delivery Systems (Design-Build-Operate-Transfer), Biogas, Biogas To Biomethane, Biogas Utilization, Greenhouse Gases, Heat recovery, Renewable Natural Gas

Author(s)

Auerbach, Eric, Allen, Shayla, Whittaker, Lauren

Author(s)E. Auerbach1, S. Allen1, L. Whittaker2

Author affiliation(s)Arcadis, 1City of Mesa, 2

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date May 2025

DOI10.2175/193864718825159785

Volume / Issue

Content sourceResiduals and Biosolids Conference

Word count22

Description: The Road to Resource Recovery - Equipment Procurement, Natural Gas Utility...

The Road to Resource Recovery - Equipment Procurement, Natural Gas Utility Negotiations, D3 RINs, and IRA Credits for an Enhanced Energy Recovery Project

Abstract

Introduction Capital Region Water (CRW) in Harrisburg, PA is embarking on a project to convert its 22 MGD Advanced Wastewater Treatment Facility (AWTF) to a true resource recovery facility through an Enhanced Energy Recovery Project. This project takes a multifaceted approach to maximize the biosolids energy extracted and beneficially utilized including the following: - Thickening upgrades to enhance percent Total Solids (%TS) in digester feed - Hydrolysis of Waste Activated Sludge (WAS) using a Thermal-Alkaline process - Importing local High Strength Waste (HSW) and blending into digester feed - Implementing Renewable Natural Gas (RNG) and interconnecting with an existing Natural Gas (NG) utility gas injection station adjacent to the plant This project is a culmination of a long-term planning, design, and implementation program that took a holistic view of the facility to devise a comprehensive resource recovery strategy. This strategy allowed CRW to invest in fundamental solids infrastructure (thickening) as well as embrace new technology (Thermal-Alkaline Hydrolysis) all while providing significant financial returns and sustainability benefits. Biogas production is expected to double and be 100% utilized as renewable fuel. Revenue from monetizing RINs and tipping fees from HSW will more than offset the cost of the project (including annual debt service on capital) with net revenue from the project expected to exceed $1 million/year. As this program developed from planning in 2018 to currently ongoing construction, there were a variety of changes in the resource recovery landscape that needed to be accounted for. These included: - Rising value of D3 and especially D5 RINs and emergence of voluntary markets - Material and labor shortages and resulting inflation due covid and global conflict - Passing of the Inflation Reduction Act (IRA) - RFS update to amend rules governing D3/D5 splits for co-digestion These developments led to a variety of new challenges and benefits that shaped how CRW and its engineering partners went about executing their vision for enhanced energy recovery. This paper details the various endeavors undertaken to keep up with the fast paced change as the project moved from planning to implementation. Procurement of Lysis A specialized Thermal-Alkaline Hydrolysis (Lysis) process was selected to enhance digestibility of sludge while increasing digester solids feed concentrations and lowering viscosity. The Lysis process was procured under a separate equipment procurement contract with the supplier, which will then be assigned to an installing contractor. This had a number of benefits including: allowing the design of WAS thickening and Lysis as one unified process, accelerating the delivery of long lead time equipment, and locking in pricing to mitigate against rising inflation. As provisions and timelines for the IRA came to light, early procurement of this equipment also became a tool when seeking to officially start construction before 2024. Negotiations with Natural Gas Utility There is a natural gas peaker facility located directly adjacent to the CRW plant. This facility stores pressurized natural gas and injects it into the grid on very cold days to augment local gas pipeline supply. The entity operating this facility is an unregulated energy services division of the local distribution company which means that they not only can provide access into the pipeline but could also serve as the buyer and monetizer of RINs. This was advantageous as it allowed negotiations and contracting with one single entity for both pipeline connection/injection terms, as well as gas and attribute sales. It also created natural incentives for cooperation and streamlining interconnection terms, as the energy services entity would also be losing profit if the interconnection was shut in. In this spirit of cooperation, there was a single gas monitoring station owned and maintained by the energy service entity but located on the CRW plant site with foundations and utilities provided by CRW. For the jurisdictional gas piping connection from the RNG skid to the interconnection station, the CRW installing contractor is responsible for the earthwork while the energy services entity will deploy its own expert staff to install and certify the pipe. Retaining D3 RINs with Co-digestion Acceptance of HSW was identified during planning due to local food producers such as Hershey Creamery and Utz Potato Chips creating an abundance of high-quality digester feedstock. Original plans included blending this HSW with feed sludge and accepting a lower value D5 RIN as the financial basis of the project. CRW wanted to maximize sustainability benefits of the project while also providing a local outlet for organic recycling and were willing to sacrifice D3 RIN revenue for these goals. During design, steps were taken to segregate HSW and inject it separately into a single digester to retain D3 RINs in one of two plant digesters. This added cost and complexity to the project and limited digester capacity to accept HSW. In June 2023, the EPA released updates to the RFS which amended rules around co-digestion and created pathways to retain D3 RINs in a digester that was receiving a mix of sludge and HSW. Due to this change the design was altered to return to a single, blended digester feed. This not only reduced project cost and complexity, but also assisted in digester feed hydraulics. The heated and lyzed sludge from WAS Lysis is blended in-line with HSW directly at the receiving tank for use as a pumpability enhancing transport medium. Provisions for the new co-digestion rules under the RFS included the requirement to establish a baseline of biogas production with just sludge to set D3 RIN benchmarks, with biogas production above these benchmarks being counted as D5. This lead to a significant baseline data analysis effort as well as staging of the project to get the WAS Lysis system up and running prior to injecting HSW so that the D3 baseline benchmark for the plant can include Lysis benefits. IRA Credits and Timelines The passing of IRA legislation in 2022 created a groundswell of activity in the field of resource recovery from biogas, with a number of credits (including Investment Credit 48 - Energy Property) providing the potential for tremendous capital cost offset in the form of direct pay tax credits. The IRA also brings with it a slew of requirements and timelines to be satisfied, with the timelines of needing construction to start before 2025 being particular challenging to municipal entities. The engineering team engaged with tax professionals with expertise in IRA provisions to develop an effective strategy for the CRW Energy Recovery Project. One insight gleaned from working with these experts was that a credit application does not need to be confined to a single project or single contract. The strategy included establishing a fact pattern to demonstrate ongoing improvements to the overall energy system which encompasses the feedstock collection and processing, the primary digesters, and the biogas collection and utilization. Based on this view, Primary Digester rehab work conducted between 2018 and 2022 were included as part of continuous improvement effort on this system and was considered in the credit application along with the Energy Recovery Project. This yielded a variety of benefits including establishing the start of construction well before the 2025 timeline while also granting safe harbor from onerous IRA requirements that escalate with time such as domestic content provisions. Conclusion This project demonstrates the dynamic nature of the resource recovery landscape and the various activities required to keep a vision up to speed with real world implementation. The engineering role in these endeavors is no longer to simply produce plans and specifications. A true partner involves skills ranging from crafting agreements with gas companies to interpreting federal legislation, all while continuously evolving approaches to keep up with changing external factors. Currently CRW has executed the procurement contract for Thermal-Alkaline Hydrolysis, executed the interconnection and gas sales agreements, and have awarded the construction contract for the Enhanced Energy Recovery Project. From planning to implementation the original vision has persisted despite unprecedented inflation (approximately doubling capital cost over projections). By taking advantage recent changes in credit markets and legislation, the project financial outlook actually improved with a projected annual net savings to CRW in excess of $1 million (including debt service on capital). The project will also double the plant biogas production while providing a beneficial outlet for 100% of gas produced, reducing the GHG footprint by ~7,200 Metric Tons of CO2/year.

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

SpeakerAuerbach, Eric

Presentation time

10:45:00

11:15:00

Session time

08:30:00

11:15:00

SessionCase Studies & Lessons Learned

Session number27

Session locationOklahoma City Convention Center, Oklahoma City, Oklahoma

TopicHigh Stength Waste, Renewable Natural Gas, thermo-chemical hydrolysis

Author(s)

Auerbach, Eric

Author(s)E. Auerbach1, J. Rosentel2, N. Taylor1, S. Allen1

Author affiliation(s)Arcadis 1; Capital Region Water 2; Arcadis 1; Arcadis 1;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Jun 2024

DOI10.2175/193864718825159423

Volume / Issue

Content sourceResiduals and Biosolids Conference

Word count24

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Allen, Shayla

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