Client Needs

In 2023, Washington State University (WSU) and the Environmental Research and Education Foundation (EREF) engaged ECS to build a research CASP to help identify new compost emissions factors. ECS engineered a two-bunker reversing CASP at the WSU campus in Pullman, WA which Dr. Tom Jobson and his team used for their initial emissions research. Thanks to apple maggot quarantine and climate considerations, it became clear that to comprehensively assess emissions factors in Washington, a comparable research facility would need to be built west of the Cascades. The new research CASP will be used to derive emissions factors from the west-sides’ regional feedstocks and inform future policy and permitting conversations in the state of Washington and beyond.

ECS Solution

WSU received additional funding from the Department of Ecology for this second research CASP, and contracted ECS to build it at the WSU extension campus in Puyallup, WA. This new composting system, brought online in January 2025, is a reversing, pipe-on-grade CASP. The two 60-cubic yard bunkers were constructed using concrete block walls and pipes made out of engineered HDPE for durability. Continuous temperature tracking and system performance indicators (duct pressure, air flow, direction) allow researchers to maximize their control over the system and their data.

When the reversing aeration system runs in negative, process air is exhausted to a freestanding pipe-on-grade biofilter.