The three compartment septic tank is composed of three connected tanks, which are connected by a fecal pipe in the middle. It is mainly based on the principle of anaerobic fermentation, the proportion of intermediate feces and parasite eggs is greater than that of general mixed liquid and easy to precipitate. After more than 30 days of fermentation and decomposition of feces in the tank, the middle fecal liquid flows from 1 tank to 3 tanks in order to achieve the purpose of sedimentation or killing parasitic eggs and intestinal pathogenic bacteria in feces The third pool of manure becomes a high-quality fertilizer.
The fresh feces enter the first pool through the fecal inlet, and the feces in the pool begin to ferment and decompose. Due to the different specific gravity, the fecal liquid can be naturally divided into three layers: the upper layer is paste dung skin, the lower layer is block or granular excrement, and the middle layer is relatively clear fecal liquid. In the upper layer and lower layer, the most bacteria and parasite eggs were found in the upper layer and the lower layer, while the middle layer contained the least number of eggs. The initial fermentation of the middle layer liquid overflowed through the fecal tube to the second pool, while most of the unfermented dung skin and residue were kept in the first tank for further fermentation. The fecal fluid flowing into the second tank was further fermented and decomposed, the eggs continued to sink, the pathogen gradually died, and the fecal fluid was further harmless, and the fecal skin and fecal thickness were significantly reduced compared with the first pool. The fecal fluid flowing into the third pool has generally been rotten, in which the bacteria and parasite eggs have been basically killed. The third pool is mainly used to store basically harmless fecal liquid.