Structural design characteristics of black film biogas tank
The black-film biogas tank is a dam-shaped structure composed of a dam, a pipeline, and a high-density polyethylene membrane. It has the characteristics of large water storage capacity and long sewage retention time, which not only saves fertilizer costs but also helps protect land resources.
According to the structural design features of the “black membrane biogas tank” and the investigation of various farms, it was found that many “black membrane biogas tanks” had drawbacks during the construction process, which easily caused fecal leakage and caused great harm to water and soil resources. , The treatment is extremely difficult and the repair is extremely expensive, which seriously affects the service life of the digester.
First, according to the design requirements of the construction drawings, the structure and material characteristics of the dam, pipeline, and high-density polyethylene film produced by 3D geonet manufacturers were analyzed and studied; secondly, according to the structural characteristics of the dam body, a special plan for the earthwork and concrete construction was carried out; finally, according to the pipeline And high-density polyethylene film material properties (pressure resistance, corrosion resistance, hot-melt) and construction technology (pipe hot melt, pipe connection, film cutting, and film welding), put the pipe and wholesale plastic geonet into use.
The quality of engineering geomembrane is guaranteed by sampling inspection and on-site inspection. The supervising engineer is responsible for randomly sampling about 20,000-25,000 m2, and sending it to the Geotechnical Laboratory of the Hydropower Engineering Test Center for testing. The tester carefully cut the sample according to the requirements of dispersion and penetration.
According to the requirements of the “Geosynthetics Test Manual”, the test items include 11 items including the thickness of the cloth and membrane, the mass per unit area, the tensile strength, and the ultimate elongation of the composite geomembrane, the tear strength, and the breaking strength. According to the requirements of the supply contract, the fabric quality must reach 200 g/m², and the HDPE geonet manufacturers‘ thickness must be greater than or equal to 0.5 mm. Other standards should meet the design requirements.
A total of 52 samples of the composite geomembrane used in this project were sampled, of which 2 batches of samples were rejected and returned. The geomembranes used in the project are all qualified products.
An on-site inspection is the second level. Before on-site welding, check the appearance quality of the geomembrane, mainly to see if there are melting points and leaks on the surface of the membrane, whether the manufacturer’s joints are firm, whether the fabric is uniform, whether the edges are flat and free of wrinkles, etc. If quality problems are found, they should be dealt with in time. For problems that obviously affect the quality, such as many edge wrinkles, weak high quality HDPE geonet seam welding, irregular edges, difficult connection, etc., they should be returned to the manufacturer after being appraised by the supervising engineer.