Alternate: NYC's Biosolids Master Plan

A Biosolids Master Plan was prepared for New York City Department of Environmental Protection (DEP) on behalf of AECOM (prime) by Hazen and Sawyer, with support from SYLVIS and JK Muir. The Biosolids Master Plan was developed under the direction of DEP's Office of Energy and Resource Recovery and was a deliverable under DEP's Energy and Carbon Neutrality Plan. The objectives of the Biosolids Master Plan included support of DEP's energy and carbon neutrality goals and alignment with DEP's Biosolids Management Program guiding principles, which consider diversification, environment, equity and environmental justice, people, economy and innovation on resource recovery. The Biosolids Master Plan included: a) a 250-Mile Radius Biosolids Processing Analysis to determine common residual products and end-uses associated with the biosolids management programs of other regional utilities; b) a Market Assessment to determine the energy and carbon benefits of various product and end-use combinations, such that DEP can plan to access markets that support its goals; c) a Multi-Facility Consolidation Solids Plan which explored economic, energy, and carbon impacts of various scenarios for DEP's future biosolids management; and d) short-term recommendations based on the Market Assessment and a long-term plan (roadmap) for DEP's biosolids management in 2050. The 250-Mile Radius Biosolids Processing Analysis and Market Assessment were used to inform selection of various product and end-use combinations for consideration as candidates for DEP's biosolids management in 2050. A solids production analysis was also completed to quantify DEP's existing solids handling as of 2018 and project these loads through 2030 and 2050. The Multi-Facility Consolidation Solids Plan considered two (2) baseline scenarios for the years 2018 and 2030, respectively, and ten (10) future scenarios for the year 2050, based on permutations of in-plant technologies for solids processing, transshipment of solids between plants, additional processing, and end-use markets. A Multi-Facility Tool was developed for scenario modeling, and to compute economic, energy, and carbon metrics for the future scenarios alongside the 2018 operational baseline and 2030 planning baseline (reflective of DEP's short-term Solids Production Plan). A group of stakeholders from DEP evaluated the scenario results using Multi-Criteria-Decision-Analysis (MCDA), allowing stakeholders to independently develop priority weighting of quantitative and qualitative criteria (mapped to DEP's Biosolids Management Program guiding principles) through pairwise comparison. Criteria included: risk (volume reduction), capital cost, operating cost, GHG emissions, energy balance, staffing requirements, environmental justice and technology maturity. The arithmetic averages of participant responses were used to assign relative weighting to the criteria, to reflect the group consensus, resulting in a set of weighted goals with which to score the final scenarios against each other. Each scenario was given a cumulative score out of 100 using these weighted goals. Of the ten (10) future scenarios considered, five (5) stood out, scoring between 75 and 88 in the MCDA. Draft results indicate the range of carbon footprints across the five (5) scenarios that scored highest in the MCDA is -0.05 to -0.19 metric tonnes of carbon dioxide equivalent per dry ton of solids produced (MT CO2.e/DT). This is an approximate average 0.30 MT CO2.e/DT reduction from the 2018 operational baseline and represents a shift from being a carbon source to a carbon sink. Overall, these five (5) scenarios performed best in Multi-Criteria-Decision-Analysis as they either converted the carbon in the residuals to energy that offsets fossil-fuel derived energy use, or permanently sequestered much of the carbon in the ground thereby avoiding degradation back to atmospheric carbon dioxide. Three (3) of the five (5) proposed scenarios involve thermochemical stabilization (pyrolysis or gasification) in which biomass is heated in the absence of an oxidizing agent to produce syngas, bio-oil, and biochar, a lightweight residue of carbon and ashes. The draft outcomes of the Biosolids Master Plan provide a roadmap for DEP's Biosolids Management Program operational and capital planning over the next three (3) decades. The range of scenarios that best supported DEP's weighted goals (scored highest in the Multi-Criteria-Decision-Analysis) will provide DEP with flexibility in execution, technology adoption and market diversification. Final results and outcomes will be presented at the conference.