An anerobic digester is built on the farm, where the manure is collected.  The design chosen by Blue Spruce Farm in Bridport was a solid concrete tank with a solid concrete cover.  The top of the tank is level with the ground.  The digester is large, roughly 14 by 72 by 100 feet, and looks similar to a feed bunker.  Other designs have a flexible cover, and still others are built using an upright gas-tight silo.  The gas is created by bacteria, which produce "biogas".

The anaerobic digestion process works by holding the farm waste at roughly 100 degrees for 20-plus days. In the process, the volatile solids are first converted to acids that become the feed for bacteria. After the bacteria work their magic, the waste emerges from the digester as more consistent slurry, with significantly reduced odors. Gas produced by the bacteria builds up pressure in the concrete vessel, and a pipe delivers the gas to a modified natural gas engine. The gas is then burned to generate electricity, which is fed onto the CVPS electrical system.