Site\nSuitability\nand Air Pollution Impacts of Composting\nInfrastructure for California’s Organic Waste Diversion Law

California’s\norganic waste diversion law, SB 1383,\nmandates\na 75% reduction in organics disposal by 2025 to reduce landfill methane\nemissions. Composting will likely be the primary alternative to landfilling,\nand 75–100 new large-scale composting facilities must be sited\nin the state to meet its diversion goal. We developed a strategy for\nevaluating site suitability for commercial composting by incorporating\nland-use, economic, and environmental justice criteria. In our Baseline\nscenario, we identified 899 candidate sites, and nearly all are within\na cost-effective hauling distance of cropland and rangelands for compost\napplication. About half of sites, mostly in rural areas, are not\nwithin a cost-effective collection distance of enough municipal organics\nto supply an average-sized facility. Conversely, sites near cities\nhave greater access to organics but cause greater health damages from\nammonia and volatile organic compounds emitted during the composting\nprocess. The additional required composting capacity corresponds to\n$266–355 million in annual damages from air pollution. However,\nthis excludes avoided emissions from landfilling, and damages could\nbe reduced by 56% if aerated static piles are used instead of windrows.\nSiting a higher number of smaller decentralized facilities could also\nhelp equally distribute air pollution to avoid concentrating burdens\nin certain communities.