Specification for construction process of black film biogas digesters

　　Construction process: excavation of earthwork ->pre buried pipelines ->excavation of anchor trenches ->laying of bottom black film ->laying of top film ->backfilling of anchor trenches

　　A. Process flow: (Construction of the tank) Build a black film biogas tank on the breeding farm, and the civil construction location is determined by the specific situation of the breeding farm. The depth is generally 3-4 meters, and the slope ratio is between 1:1 and 1:2.

　　To ensure normal gas production, the height of the dam should not exceed 500. The bottom discharge port of the pool should be 30-1250px lower than the bottom of the water inlet for the collection and discharge of biogas residue. Excavate an anchor hook 1.5m from the edge of the biogas digester, with a width of 1m and a depth of 1m, to fix the bottom and top membranes

　　B. Process flow: (Pipeline laying) After the excavation of the biogas tank, the inlet pipe, outlet pipe, slag discharge pipe, and exhaust pipe are laid according to the actual situation on site, and the slag discharge outlet is located in the bottom depression.

　　The water outlet is in the middle, the water inlet is 1 point perpendicular to the dam mouth, and the exhaust pipe is on the top. (The water outlet and slag discharge outlet are in the same direction and diagonally opposite the water inlet)

　　C. Process flow: (Bottom membrane laying) Bottom membrane laying of biogas digester: HDPE anti-seepage membrane with a thickness of 1.0mm is used. HDPE film has good anti-corrosion performance, anti leakage performance, anti-aging, UV resistance, etc.

　　D. Process flow: (Top film laying) Top film laying of biogas digester: 1.5mm thick new HDPE black film (with the same performance as the bottom film) is used, which can be exposed and normally used for 10 years (the bottom film can be used for a long time, and the facial mask can be replaced when the service life expires).

　　Cut HDPE anti-seepage film according to the actual terrain size on site, and lay it in sequence to cover the entire biogas tank. After the top membrane is laid, the welded bottom membrane and top membrane around are buried and fixed in the anchorage.