Tubular Polyethylene Digester (TPED)

Biogas is a concoction of gases (i.e. CH4, NH4, CO2, H2S, moisture) produced by the fermentation of animal wastes, human sewage and other organic materials in an airtight or anaerobic condition.  Biogas is rich in methane (55-70%) that could be used as fuel for cooking stoves, heat lamps, and engines used to generate electricity.  By products of biogas production are also used profitably.  The solid residues (sludge) are commonly used as soil ameliorant, while the nutrient rich effluent is an excellent fertilizer. As long as methane is burnt completely, biogas fuel does not pollute the environment.  Methane in its molecular form is one of the gasses known to degrade the ozone layer.
The tubular Polyethylene Digester (TPED), developed by the Bureau of Animal Industry of the Department of Agriculture is a biogas technology for smallhold swine farmers.  TPED is simple, cheap and easy to install.  For a measly P5,000-P6,000, you can have TPED in your backyard.  TPED can provide you a steady supply of fuel for 24-hour cooking, thus cut LPG expenses.  In addition to your savings, you also eliminate the foul odor of decomposing animal manure.  For more information on this technology, you can contact the BAI-DA at telephone number (02)920-4769.

Source: Gabay sa Pangangasiwa ng Triple Cross na Baboy, PCARRD Farm Primer No. 18/2000.