Top: Covered aerated static pile pilot plant being constructed in Pullman (left); emissions chamber sampling kit (right); Photos courtesy Engineered Compost Systems

Washington State University (WSU) researchers received a $2.5 million grant from the Washington State Department of Ecology to study emissions of volatile organic compounds, methane, and carbon dioxide gas from composting. Emissions will be measured in aeration ducts and on compost pile surfaces. The data will be used by state regulators for air emissions permitting of composting facilities. Led by Tom Jobson, a professor in the Department of Civil and Environmental Engineering, the project will measure emissions from green waste/food waste mixtures composted at a pilot continuously aerated static pile (CASP) system supplied by Engineered Compost Systems in Pullman at the WSU Compost Yard. Another pilot plant is at WSU’s Puyallup Research and Extension Center. Because emissions are thought to vary depending on types of feedstock material and composting conditions like temperature and air flow rates, the two pilot plants will examine regional feedstock differences. Compost feedstocks collected from commercial facilities west of the Cascades will be composted at the Puyallup pilot plant, and materials collected from facilities east of the Cascades will be composted in Pullman.