The type of Biodigester that we mostly work with is a Tubular system it is constructed with plastic  (polyethylene), bricks, and cement. The biodigester, being flexible plastic, must be semi-buried in an open trench in the ground and two chambers will be located at the beginning (inlet-feeding) and end of the system (outlet – Bio slurry). The possible sizes of the Biodigesters are 3 m , 6 m , 9 m , and 15 m , for the commercial-grade, two of them are installed in parallel for bigger production of Biogas. The main reason why we prefer to work with this tubular system made of polyethylene is because of the durability of the plastic material (being exposed to the aggressive slurry), resistance to mechanical stress, and UV radiation, as well as their gas permeability. Plastic digesters have proven quite suitable, as long as the in-service static stresses are accounted for in the manufacturing process, and display good gas-tightness and corrosion resistance. They are easy to repair and have a long useful life span.