PURPOSE: Droppings of human being, domestic animals, poultry and raised fish are completely reutitlized by combination of methane fermentation vessel, photosynthesis bacteria vessel, algae cultivation vessel, etc.

CONSTITUTION: Droppings from inlet 1 is fermented in methane fermentation vessel 3 and the liquid part of the product is sent through filter 42 to photosynthesis bacteria vessel 4. The gases evolved by methane and photosynthesis bacteria is temporarily store in chamber 5, then sent through pipe 12 to the algae cultivation vessel 6 where a part of the gas is consumed as a nutrition source and the remaining is stored in gas holder 9. The stored gas is sent through pipe 11 and inlet 21 into scrubber 7 where the gas is scrubbed by jetting pure water. The scrubbed gas is temporarily stored in gas holder 10, then sent through pipe 43 and liquefied for storage by liquefier 47 or burnt in gas ranges 37.