Abstract: A plant for production of fuel gas by anaerobic fermentation of organic materials comprises a pit-like hemispherical fermentation chamber and a flexible and foldable cover which, when inflated, has the form of a complementary hemisphere and is in open communication with the fermentation chamber at the horizontal equatorial plane. Organic materials are introduced into the fermentation chamber to the level of said plane. The cover is weighted to be foldingly contracted when unpressurized and to be inflated to its hemispherical form by generated gas.

Abstract: A method of aerobic decomposition of organic solids involves mixing material containing the organic solids to be decomposed with relatively drier material in order to set an upper limit to the dampness of the mixture to be processed. An apparatus for aerobic decomposition includes a decomposition reactor in the form of a tower which tapers in the upward direction. The bottom of the reactor is square or rectangular in cross section and its top is oval or circular in cross section. The bottom of the reactor is made in the form of a roller grid. A mixing section is provided for mixing the material to be decomposed with relatively drier material.