Improving Biosolids Management Resiliency Through Regional Collaboration Among 15 Agencies

[b]APPLICABILITY[/b] Over the past several years, wastewater treatment plants across the country have experienced restrictions and disruptions to biosolids end uses driven by legislative and regulatory actions. Among these challenges are limitations on land application and landfill availability, legislative threats, increasing costs, and consolidation of providers. Collectively, these factors have reduced agency resiliency. Other agencies possess greater levels of resiliency but seek to reduce costs and risk or further diversify their portfolios for long-term reliability. Within this landscape, 15 Southern California (SoCal) agencies, Participating Agencies (PAs), joined to form the Southern California Regional Biosolids Coalition (SoCal RBC) and complete a study to determine the feasibility of establishing a regional, publicly owned and operated biosolids management facility. This facility would be one of the largest of its kind and would treat the biosolids generated by a significant portion of SoCal's population. The study was split into phases, with Phase 1 completed. This phase sets the basis for facility sizing, siting, viable technologies, and considerations related to governance and public engagement. [b]RESULTS [/b] [b]Methodology[/b] The methodology of the feasibility study focused on five elements: •[i]Current practices:[/i] A survey was developed which covered each PA's project drivers, biosolids management strategies, biosolids characteristics, and biosolids contributions to the proposed facility. •[i]Regulations and market conditions:[/i] The regulatory and market considerations in SoCal for building a biosolids facility and distributing biosolids for beneficial use were analyzed. Other regional efforts across the US were also reviewed and lessons learned were incorporated into our guidance. •[i]Alternatives development:[/i] The universe of potential sites and technologies were evaluated to develop a shortlist of three sites and treatment options. •[i]Governance:[/i] Governance models were reviewed, and three governance options identified. •[i]Strategic public engagement:[/i] Key messaging themes for public engagement were developed and a plan for public outreach was established. [b]Results[/b] [i]Current Practices[/i] Figure 1 shows the current biosolids end uses and backup management options for each of the PAs. This study determined that a regional facility would be initially sized to accommodate a low-capacity 2030 estimate with room to expand up to a high-capacity 2060 estimate. [i]Regulations and Market Conditions[/i] Many large agricultural counties in SoCal have severe restrictions on land application, which increases hauling distances for beneficial use. Additionally, while per- and polyfluoroalkyl substances (PFAS) regulations are not yet implemented in California, concern about these contaminants is mounting and considering the potential for future PFAS regulations is prudent. Additionally, three air districts were considered relative to siting a regional facility. The most restrictive air district would likely require a Title V permit and offsets. A market assessment was also conducted and concluded that the SoCal RBC should focus on producing a Class A product because it is the most resilient, understanding that it is unlikely to generate reliable or significant revenue. [i]Alternatives Development[/i] Figure 2 shows the universe of site and technology alternatives considered. Due to the evaluation criteria chosen by the PAs, advanced thermal technologies were eliminated during screening. However, to address PFAS concerns, the future addition of such technology was considered when assessing footprint. Three sites and biosolids treatment options were ultimately chosen for more detailed analysis, shown in Figure 3. Class 5 capital cost estimates and site layouts were developed, and 20-Year Net Present Worth costs were calculated. Figure 4 shows the non-economic evaluation conducted and Figure 5 shows the cost comparison. As shown in Figure 5, composting has the lowest capital cost but highest operations and maintenance costs. Of the two dryer alternatives, total costs are lower for rotary drum drying. While operated at a lower temperature than drum drying, belt drying has a greater natural gas (NG) cost to handle higher exhaust volume due to the increased NG requirements for RTO operation which is required for the SoCal air districts. [i]Governance[/i] This study also evaluated possible governance structures for the SoCal RBC. The three viable governance structures identified are shown in Figure 6. [i]Strategic Public Engagement[/i] This study also identified key messaging themes for future public engagement, shown in Figure 7. From there, a public engagement plan for implementation in future project phases was developed and stakeholders identified. [b]Conclusions[/b] This collaboration among 15 PAs focuses on advancing a resilient biosolids management solution and represents one of the largest collaborations of its kind. Subsequent phases of this project will advance one of the short-listed options through preliminary design and possibly through to final implementation. The approach taken and key findings from this work, including siting, technologies, governance, and public engagement may be useful for other regions and groups considering options to increase their biosolids management resilience