Palo Alto, Ca'S Integrated Source-Separated Organics Management Solution to Achieve Zero Waste Goals

Several precursors led to the execution of the Palo Alto, CA Biosolids Facility Plan at the Regional Water Quality Control Plant (RWQCP), which include:1. In September 2011, Palo Alto completed a comprehensive Feasibility Study (conducted by Alternatives Resource Incorporated (ARI)) assessing options to manage source-separated organics (Food Scraps, Yard Trimmings and Biosolids). This project resulted in an RFP for Professional Services of Energy/Compost (E/C) Facility or Export Food Scraps, Yard Trimmings and Biosolids. Proposals for the E/C project were received on August 13, 2013.2. Concurrent with the separated organics Feasibility Study, Palo Alto completed a Long Range Facilities Plan for the RWQCP, which recommended phasing out the existing, multiple hearth furnaces (MHF) used for wastewater residuals incineration. The study recommended examining alternatives to incineration for residual management including onsite/offsite anaerobic digestion or gasification as well as dewatering and hauling for offsite use/disposal.3. In November 2011, voters in the City approved Measure E, allowing a 10-acre parcel at the abandoned City Landfill (now a park) to be used for the E/C Facility and thus enable decommissioning of the MHF by 2019.4. In September of 2012, Palo Alto issued an RFP for a Biosolids Facility Plan to be conducted in parallel with the E/C Facility RFP. Palo Alto selected CH2M HILL (with teaming partner RMC Water and Environment) to lead that study to examine biosolids only alternatives alongside the E/C proposals. The result will be a long term biosolids solution that enables timely decommissioning of the MHF and construction of replacement facilities to reliably process the RWQCP biosolids, either for biosolids only or for integrated organics including biosolids.This paper describes the biosolids facility plan evaluation, planning process, and results. The methodology for evaluation includes multi-attribute utility analysis including both financial and nonfinancial criteria for robust decision making as well as in-depth energy balance and greenhouse gas analyses for each option.Several wastewater residuals stabilization and dewatering and hauling technologies were evaluated, with considerations for capital cost, operation and maintenance cost, and non-financial factors such as renewable energy generation, greenhouse gas emissions/offsets, diversity of end-use options, odors, truck traffic, and local control of end-use product. In addition, the Palo Alto City Landfill adjacent to the RWQCP provides options utilizing landfill biogas.The combination of scores resulted in a cumulative “Benefit” score for each biosolids option. The relative contribution of each criterion is shown. Without consideration of the project cost, Thermal Hydrolysis received the highest benefit score.