GMT Designs a Large Scale Composting System for Cowlitz Valley Compost

CLIENT CHALLENGE

Swanson Bark and Wood Products is a leading manufacturer of bagged mulch products for the landscape industry. They were interested in adding compost to their product line and saw an opportunity to install a composting plant and increase their revenues with green waste tipping fees. Swanson wanted complete control over the compost process because they pride themselves on the quality of their bagged products. They formed a new company, Cowlitz Valley Compost (CVC), in alliance with Clackamas Compost who was shutting down their facility in the Portland area. In order to achieve quality compost at a large scale, they contacted Green Mountain Technologies (GMT) to design a composting system that met their needs.

GMT SOLUTION

Cowlitz Valley Compost (CVC) began composting operations early in 2016 using an Aerated Static Pile (ASP) compost system designed by GMT. CVC considered both windrow and ASP technologies, and selected ASP because of the compact footprint that reduced the size of their impermeable surfaces and storm water catchment pond. CVC Manager Steve Sheet provided clear operational and handling goals, and Terre-Source Owner Tamara Thomas provided permitting and operations plan documents. GMT translated these documents into 3-D modeling and construction drawings.

The ten-zone mass bed ASP system uses above ground HDPE pipes to aerate the piles that measure 80’ long by 30’ foot wide. Two large blowers pressurize two manifolds mounted off the poured concrete back wall and zone dampers are used to control the volume of air needed to regulate the piles to temperature set points. Hard wired temperature probes send the current zone status to the GMT Web-MACS controller which decides how wide to open the damper, and how fast to run the blower to keep the correct system pressure. This simple system allows the compost curing to be done without further aeration directly across from the active compost piles.