How to Build a Biogas System

Biogas, also known as swamp gas, is made of methane and carbon dioxide together with traces of carbon monoxide, nitrogen and hydrogen. Biogas is produced from waste material and has proved to be an invaluable alternative to fuel. In rural areas, households use biogas for cooking and lighting lamps. Biogas is produced by decomposing waste materials under anaerobic digestive processes, which means digestion without the help of oxygen. Biogas may be upgraded and used as a vehicle fuel. Biogas may be produced at home with the help of a biogas digester.

Things You'll Need

• HDPE tank
• Plastic welder
• 3/4-inch HDPE welding rod
• 1/4-inch HDPE sheet
• 3/8-inch HDPE sheet
• 3/4-inch gas vent
• 2-inch transfer pipe
• Plastic hoop
• Heat exchanger assembly
• Self-tapping stainless screws
• HDPE sheet cutter
• 2-inch' Influent in pipe

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Instructions

• 1

  Weld a plastic hoop in the middle of the HDPE tank, such that it splits the tank into two chambers. This will form a foundation for the baffle.

• 2

  Cut a disk of the same diameter as the hoop from a 1/4'-inch HDPE sheet.

• 3

  Cut three holes in the disk for the following fittings: 3/4-inch gas vent, 2-inch transfer pipe (center) and a 2-inch influent-in. Assemble a transfer pipe and influent-in pipe on the disk. This disk is used as the baffle plate.

• 4

  Attach the baffle plate to the foundation support provided by the plastic hoop by means of self-tapping stainless steel screws sealed in with silicone caulk.

• 5

  Cut the biogas tank lid from a 3/8inch thick HDPE sheet to fit in the open HDPE tank. This diameter varies according to the diameter of the tank.

• 6

  Cut holes in the lid for an influent/effluent heat exchanger, outgoing biogas, biogas recirculation and a gas vent.

• 7

  Assemble the lid with a gas vent hose and gas recirculation conduit attached to fittings. Install the lid on the HDPE tank.

• 8

  Wrap the heat tape around the tank and attach it to aluminum tape.