Cedar Grove Compost: Developing a Combined Food-Yard Waste Centralized Composting Program

Abstract

Cedar Grove Composting started in 1989 in Maple Valley, WA (in King County, approx. 25 miles SE of Seattle). The company is a private, family-owned business that also has sister companies that collect and process used oil, wastewater, solvents, and hazardous waste. The family business, Seattle Disposal, started collecting Seattle’s garbage with horse and buggy in 1938. In 1989, the city of Seattle approached Seattle Disposal about composting grass clippings and yard prunings (i.e. yard waste) instead of landfilling. A third collection bin was added for the yard waste, in addition to the garbage and recycling bins, for residential collection. All the material that was collected by the two city haulers was taken to the one of the two city transfer stations, then hauled by the city to Cedar Grove. Cedar Grove Composting was formed (it’s named originated from being located on Cedar Grove Rd.) and began its windrow operation. Volumes quickly grew and other, higher control, composting technologies were employed over time: Open windrows gave way to static piles, then to negatively-aerated static piles that vented to biofilters, and multi-phased large piles.