Small sewage purification the digesters applications at room temperature anaerobic fermentation technology, in accordance with the principle of "multi-level gravity, step by step degradation, the establishment of the anaerobic fermentation of grade Ⅰ - Ⅱ grade facultative digestion filter new device. By anaerobic fermentation, facultative digestion and filtration, sewage backflow and fill process. Sewage in most of the organic matter to produce biogas by anaerobic fermentation, after fermentation of sewage into the facultative digestion filtering pool, part of the decomposition of organic matter has been further degraded. Settling down part of the organic matter and activated sludge back to the anaerobic fermentation tanks to increase the effect of anaerobic fermentation, and will reach the goal of purification. 
 Sewage purification digesters is a small, decentralized wastewater treatment unit, with less investment, the effect is good, run without energy support. Currently the technology has been widely used in Lianshui, the East China Sea, the effectiveness of the more significant.