A polyethylene tank with a thickness of 3.2 mm was used to create a modified Chinese fixed dome digester based on typical Chinese designs [20,41]. As with typical fixed dome digesters the design consists of three main components (Figure 4): (1) A 0.15 m3 loading tank where fresh manure was diluted prior to loading the digester; (2) a 1.14 m3 digestion chamber with 85% working volume occupied by slurry and 15% gas storage space; and (3) a 0.39 m3 displacement tank. These components are connected by 15.24 cm PVC pipes (Figure 4). To insulate the digester it was sprayed with polyurethane foam (Tiger FoamTM insulation) to a thickness of 2.5 cm and buried inside a greenhouse to a depth 2.19 m. The greenhouse, in which the digester was located, was not insulated, heated, or completely sealed, but did protect the experimental equipment from rain and wind.