Top: Pipe on grade aerated static pile composting site in Billings, MT (top). Block push wall and aeration equipment (bottom). Photos courtesy Green Mountain Technologies

The Billings, Montana Department of Public Works commissioned a new biosolids and yard trimmings composting facility in August 2024 to reduce the cost of landfilling these materials and to meet sustainability goals. The aerated static pile (ASP) composting facility has capacity to process up to 25,000 tons of material annually and is expected to extend the life of the current municipal landfill by at least ten years, according to the city. The composting equipment was designed and provided by Green Mountain Technologies (GMT). It includes a pipe on grade ASP system with an ecology block push wall, explains GMT. The aeration system zones are all connected to one aeration blower, with specialized valves that are opened and closed by GMT’s “WebMACs” control system to track data obtained from in-line sensors and determine the aeration levels of each zone. After the primary aeration phase is complete (three to four weeks typically), the material is moved off of the aeration pad and formed into windrows for a curing period before it’s ready for use as a landscaping soil amendment.