Case study of black film biogas digester engineering

　　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 the cost is approximately 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, and 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 tank, which can effectively reduce the accumulation of sludge in the tank.

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

　　HDPE geomembrane is installed inside the biogas tank 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, a layer of geotextile film is laid above the biogas digester, welded to a completely sealed position, and fixed with anchor hooks around it to form a closed space.

　　After this treatment, the wastewater generated from aquaculture is discharged into a biogas digester, where it undergoes anaerobic fermentation to produce biogas. The discharged wastewater can also be effectively treated to achieve a dual effect. Especially in summer when there is sufficient sunlight, the black film can absorb solar heat and increase temperature, which is beneficial for increasing gas production.