Need to leave the exhaust port to avoid the accumulation of methane gas in the tank, an explosion.
Septic tank is a storage of sewage structures, there is water there are various gases, set up the appropriate aperture of the exhaust hole on the sludge removal and transportation is favorable.
Septic tank is the most primary stage of sewage treatment, only 50% of the suspended impurities (feces, larger pathogens, etc.). But it can make the accumulated mud in anaerobic conditions to decompose into a stable state, ripened and used as agricultural fertilizer.
General requirements for septic tank site
(1) toilet as close as possible to the living room, to do the toilet into the courtyard, that is, easy to apply, but also easy to manage.
(2) The toilet should be built in the downwind direction of the living room and kitchen.
(3) Sanitary toilet as far away as possible from the well or other underground water pipe network.
(4) Toilet house can be used to reduce the cost of houses, fences and other original walls.
(5) The underground part of the toilet should be built outside the house or fence, which is conducive to the maintenance and manure, slag removal.
(6) The construction of toilets should be in line with the village construction plan, do not build on both sides of the road.
Baidu Encyclopedia-Septic Tank