After fermentation, decomposition and precipitation in the first tank, manure is naturally divided into three layers because of its different specific gravity. The upper layer is pasty dung skin, the lower layer is flocculated dung residue, and the middle layer is dung cleaning and smelting. The middle-layer fecal liquid enters the second tank from the fecal tube to continue anaerobic fermentation and enters the third tank for storage.
The feces are dissolved, precipitated and anaerobically fermented in the first and second tanks to intercept parasite eggs, and the virus in the feces is killed harmlessly under anaerobic conditions.
Extended data
The volume of three-room septic tank should be determined according to the number of users, the amount of flushing water, the fermentation and decomposition time of feces, and the sterilization requirements of egg sinking. The fermentation and decomposition time of feces and the death time of pathogens are calculated as 30 days, including 20 days in the first pond, 20 days in the second pond 10 day, and the volume of the third pond is at least the sum of the two ponds.
The volume ratio of 1 pool, the second pool and the third pool should be 2: 1: 3. Under the condition of not reducing the specified volume of 1 pool, the volume of the second pool can be appropriately increased, and the volume of the third pool can be appropriately reduced in the toilet without manure.
When the volume of the second tank is less than 0.5m3, it can be designed and built according to 0.5m3. ..
References:
Baidu Encyclopedia-"Three Formats" Septic Tank