The production of biogas, which is regarded in many countries as a by-product of an efficient system of energy production, has become in China a comprehensive, controlled method of waste disposal, recycling resources, supplying energy and fertilizer and improving rural health, as the digesting of wastes in a closed container kills many of the pathogens responsible for common human diseases.There are already approximately seven million biogas pits in opertion, with Sichuan (Szechuan) province leading the country in a movement to extend the practice throughout the countryside. This manual describes in detail how to build the pit, and covers a full range of designs to suit various soils from sandstone to sheer rock. It also includes a description of how the original manual was used.