The black film biogas digester integrates fermentation and gas storage, and is welded and sealed with materials such as HDPE anti permeability membrane. It has the advantages of convenient construction, high efficiency, and low cost, and its cost is about one tenth of that of a conventional biogas digester.

This type of black film biogas digester has low maintenance cost, convenient daily management, long sewage retention time, good sealing performance, especially in sunny conditions. The black film can absorb sunlight heat, increase temperature and insulation, and produce more biogas. Generally, automatic sewage and sludge discharge devices are also installed at the bottom of the black film biogas digester, which can effectively reduce the accumulation of sludge in the tank.

The principle of producing biogas in black film biogas digesters is extremely similar to that of traditional biogas digesters before. Black film biogas digesters utilize the advantages of HDPE impermeable film for anti-seepage and leakage prevention, and are laid on the pre excavated bottom of the digester

HDPE geomembrane is installed inside the biogas digester according to the process requirements of anaerobic fermentation, including inlet and outlet, slag discharge pipe, and biogas collection pipe. After laying according to these requirements, lay another layer of geotextile film above the biogas digester and weld it until it is completely sealed. Fix it around with anchor hooks to form a closed space.

After this treatment, the wastewater generated from aquaculture is discharged into the biogas digester, where it undergoes anaerobic fermentation to produce biogas. The discharged wastewater can also be effectively treated to achieve a dual effect. Especially under sunny conditions in summer, black film can absorb solar heat, increase temperature, and help increase gas production.