WEF Residuals and Biosolids Conference Resource Recovery Cooperatives for the Security of Consistent, Quality Codigestion Feedstock

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1 Resource Recovery Cooperatives for the Security of Consistent, Quality Codigestion Feedstock David McNeil, City of Tempe/Tempe Grease Cooperative Abstract: Codigesting wastewater utilities typically have regulatory control of FOG at the food service establishment (FSE), and ownership of FOG at the wastewater plant after a tipping transaction, but lose control within the shoulders of the supply chain. This loss of control between the initial regulatory transaction and the WWTP tipping transaction creates uncertainties related to codigestion feedstock security, feedstock quality and contamination, operational logistics and costs at the plant, and related economics. Tempe Arizona s use of a retailers cooperative model for FOG collection and recovery gives the utility an opportunity, through contract, for total control over the feedstock throughout the supply-chain, and for better long-term feedstock security over the operational life of FOG receiving and codigestion facilities. Background Wastewater utilities with codigestion facilities typically share the complementary goals of reducing the negative impacts of fats, oils, and grease (FOG) on municipal sewer infrastructure, and recovering FOG for renewable energy production at wastewater treatment plant (WWTP) digesters. A codigesting utility s ideal logistical lifecycle for a molecule of FOG is to effectively capture it at commercial food service establishments (FSEs) before it enters sewers, to transport it to digesters at a wastewater treatment plant (WWTP), and to fully recover and codigest it to generate renewable biogas. Current industry practices attempt to realize this lifecycle through a sequence of regulatory and retail transactions throughout the collection-transport-delivery supply chain: 1) Sewer utilities engage in individual regulatory transactions with FSEs to ensure compliance; 2) To meet their obligations under #1, restaurants engage in individual retail transactions with waste haulers for grease trap cleaning and maintenance at, and waste removal from, the premise; and 3) Utilities engage in individual retail transactions with grease haulers responsible for #2 to obtain ownership at the WWTP, where it is then codigested. 1202

2 Problem This transactional structure fails to efficiently and effectively achieve utility FOG goals at several levels, which contributes to reported FSE compliance rates with municipal FOG-related ordinances of <30% in major U.S. cities and uncollected grease rates between 800 and 1,700 lbs/restaurant/year (EPA 833-F ; EPA-833-F ), and underachievement of FOG recovery and codigestion at our nation s WWTPs (Shen et al, 2015; Fillmore, et al, 2016). First, the sewer industry s regulatory transactional structure often fails to achieve compliance at the FSE because it holds restaurants accountable for the service practices of third-party grease haulers. Accountability for cleaning practices is passed sequentially from the sewer authority to the hauler through the restaurant, requiring restaurateurs to enforce the utility s service quality requirements. This delegation of enforcement from the regulatory to the retail transaction fails because restaurateurs typically do not have the knowledge or skill sets to effectively enforce requirements through oversight of this very specialized plumbing service. The sewer agency is the sole expert of what constitutes effective and compliant cleaning practices, yet there is no direct accountability link between the waste hauler and the sewer authority (see Figure 2). Additionally, due to the fact that enforcement responsibility is delegated to the restaurant premise manager and regulatory criteria is limited to the cleaning practices at the premise only, regulatory control stops at the property boundary, beyond which both the restaurant and utility have no authority. Unregulated transport between FSEs and the final disposition site, a WWTP or other, creates obstacles to achieving both sewer management and feedstock security goals

3 Unscrupulous haulers can discharge illegally to cut disposal costs, sometimes back to the same sewers that their service was intended to protect. Uncontrolled transport can also result in feedstock contamination and digester upset, as WWTPs receiving FOG loads have no control or assurance that hauler routes excluded collection of materials that could upset digester operations. Operating a WWTP as a commercial tipping facility is not familiar industry for municipal utilities, and uncertainty regarding both consistent quantity and quality of feedstock translates to potential operational challenges for digesters, elaborate monitoring, handling, treatment and decontamination processes at receiving plants, and uncertainty about gross energy production (Parry, 2014). Lastly, receiving FOG through a commercial waste disposal transaction creates uncertainty regarding that transaction s contribution to cost-recovery for codigesting WWTPs. ket manipulations and competively fluctuating landfill costs add uncertainty to a market that is already vulnerable to fluctuating energy prices (Parry, 2014). Despite these shortcomings, most codigestion facilities continue to recover feedstock through commercial tipping operations. The traditional FOG collection and recovery structure (Figure 1) seats the utility at both the front end and the back end of the transactional sequence (i.e., the utility initiates the first regulatory transaction that compels waste removal by the restaurant, and the sewer utility is on the receiving end of the retail transaction that secures the feedstock from haulers), but suffers from the fact that the utility is absent from transactions, and transactional control of FOG, within the supply chain. If the sewer utility could gain quality control over cleaning and removal service at the FSE, and retain both ownership and control of FOG throughout transport between the FSE and WWTP, the quality control failures inherent in the traditional FOG structure could be resolved. Tempe Grease Cooperative The City of Tempe Arizona s Grease Cooperative (TGC), a municipal FOG collection and recovery cooperative run by the city s wastewater utility in partnership with community restaurants and partner grease hauling vendors, may be just the answer to retaining service and feedstock quality control throughout the FOG supply chain. Tempe found this solution by searching for a business model that would secure utility ownership of FOG waste/feedstock, and found such a model that to Tempe s knowledge had never been implemented by a local government: retailers cooperatives. Retailers cooperatives have long been used by groups of independent retailers to leverage their collective purchasing power to obtain competitive advantages in the marketplace by acquiring discounts from suppliers and sharing marketing costs through a central buying organization (see Figure 3)

4 Through the TGC, the City of Tempe serves as that buying agent for compliance requirements on behalf of local restaurants. The TGC is the first program in the world in which a regulatory sewer authority brokers both pricing and service quality for grease hauling services on behalf of regulated food service establishments (FSEs) that voluntarily enroll in this program as an alternative to being held responsible for the practices of their hired vendors (see Figure 4). As the central buying organization, the utility provides member restaurants with both discounts and compliance assurance under collective contracts that are established and administered by the utility. As a result, partners in the TGC collectively establish more sustainable plumbing and sewer infrastructure for the region, and create a more livable city by reducing odors and sewer overflows at member facilities and community-wide, all at a lower cost for both the utility and its regulated users. Unlike traditional FOG regulation, transaction management allows the City to manage services beyond the property boundary of the regulated business. In addition to GPS and other tracking requirements to ensure complete transparency in the transport and disposition stages of service, contracts with haulers establish city ownership of hauled waste, securing its availability and manageability as codigestion feedstock. The FOG collection and recovery cooperative model gives the utility an opportunity, through contract, for total control over the feedstock from grease trap to codigester. Regulatory authority at the FSE allows the use of kitchen best management practices (BMPs) to manage feedstock quality at the source. Grease trap sizing criteria and pumping requirements can be designed with maximum FOG recovery in mind. Collection routes for vendors can be established, tracked, and enforced to eliminate the risk of contamination from septage or other non-fog sources, and can even be designed to establish the optimal mix of sources for each load based on FSE-specific FOG information and digester requirements. FSE pump-out schedules can be established to best

5 equalize delivery timing and reduce onsite storage needs. If needed, member FSEs could also be solicited to contribute pre-consumer food waste to further optimize the codigestion recipe. Cradle-to-grave ownership puts the utility in the driver s seat for the entire lifecycle of removal and recovery. At the WWTP, the utility no longer has to staff and operate a regulated commercial waste disposal facility, but instead opens the plant gates only for Coop deliveries at pre-established times based on contractual schedules. Along with reductions in costs of pretreatment and decontamination resulting from better and more consistent feedstock quality, service and delivery schedules should result in lower staffing requirements and reduced costs FIGURE 5: TGC MEMBER GROWTH After three years of implementation, 182 food service establishments, or over one in six regulated food businesses in Tempe, has enrolled in the Tempe Grease Cooperative, understanding that TGC membership is the brand for restaurants that care about their business, their community, their environment, and the disposition of their waste. Based on current enrollment, the Tempe Grease Cooperative is securing almost 600,000 gallons of total grease trap waste annually. Having made the collection program a reality, Tempe is currently developing a 5-year strategic plan for the TGC, both to resolve administrative challenges identified in the first several years and to complete its core goal of recovering the city s FOG for codigestion. This latter goal is a challenge for Tempe because the city does not own or operate a WWTP within its jurisdiction, but instead has ownership stake in the regional 91 st Avenue WWTP operated by the City of Phoenix. The TGC s strategic initiatives over the next 5 years include efforts to regionalize the cooperative to benefit other cities within the Phoenix region and potentially throughout the state, to explore regional partnerships for the delivery of FOG to WWTPs, to engage restaurant industry organizations in the effort, to develop software to facilitate administration of the TGC, and to partner with other utilities and research organizations to study the economic benefits of innovative supply-chain solutions to some of the obstacles to FOG codigestion

6 Total Grease Trap Waste (gallons/year) Apr Oct Dec Feb Apr Aug Oct Dec Feb Apr Aug Oct Dec FIGURE 6: TGC RESOURCE RECOVERY TRENDS Conclusion For utilities that are already codigesting at independently owned and operated WWTPs, Tempe s resource recovery model provides an opportunity to better manage FOG at the source, to secure ownership, quality, and disposition control throughout the FOG supply chain, to receive a consistently known quantity and quality feedstock, and to establish a more facility-friendly and lower risk method of securing feedstock. The development and implementation of the Tempe Grease Cooperative not only capitalizes on existing and future waste-to-energy opportunities, but also demonstrates the value of innovative approaches to engaging private enterprise in public policies and executing innovative business delivery frameworks to create more sustainable communities. The TGC establishes a blueprint for using group discounts to promote organics recovery and other sustainable practices community-wide using the purchasing power of municipal governments. The TGC embodies the vision of a City that embraces innovation and partnership to best serve its businesses, citizens, and visitors, and a restaurant community that believes in doing the right things for both business and its environment

7 REFERENCES Fillmore, L., Deines, A., Case for Codigestion at Water Resource Recovery Facilities, BioCycle, tember 2016 Parry, D.L., Co-Digestion of Organic Waste Products with Wastewater Solids, Water Environmental Research Foundation, OWSO5R07, 2014 Shen, Y., Linville, J.L, Urgun-Demirtas, M., Mintz, M.M., Snyder, S.W., An Overview of Biogas and Utilization at Full-Scale Wastewater Treatment Plants (WWTPs) in the United States: Challenges and Opportunities Towards Energy-Neutral WWTPs, Renewable and Sustainable Energy Reviews, 2015 U.S. Environmental Protection Agency, Office of Water, National Pretreatment Program, Fact Sheet: Controlling Fats, Oils, and Grease Discharges from Food Service Establishments, EPA- 833-F ; EPA-833-F , y 2007, updated tember,