Septic tank structures of various types. They consist of an enclosed septic tank in various shapes and sizes, which then links to a secondary soil treatment system, typically a soakaway or drainfield land drainage device, or a soakaway mound.
How a Septic Tank operates Raw sewage and waste water discharges into the tank from pools, kitchens, etc., where the solids are isolated from the liquid waste. Fats and oils float down to the top of the tank, creating a coat of crust. Faeces and food scraps fall to tank bottom to create a coat of sludge. Anerobic microbes that are normal colonizers in the tank “digest” up to 70 percent of this sludge.Get the facts about Septic Tanks you can try this out.
The polluted septic water flows out of the tank into a drainfield or soakaway. The floating crust is held back by baffles or’ T ‘ pipes in the tank and prevented from entering the tank outlet. Septic tanks should be drained regularly, so that the sludge and crust levels do not become too thick. This also avoids greater and higher accumulation of suspended solids from being drained out into the soakaway. Solids may obstruct the soil drainage system’s air spaces, produce a drainage hazard, and the septic tank effluent can not soak away or be handled by the normal soil bacteria.
Variations of Septic Tank structures Standard septic tanks consist of two rectangular chambers: the first is 2/3 of the whole, and the second 1/3, typically made of brick or concrete. There are stringent construction rules in place, and septic tanks must be constructed according to BS 6297 1983. The inlet pipe into the first chamber finishes in a’ T’ pipe that passes below Top Water Level (TWL) of at least 450 mm (18), “and the chamber must be at least 1500 mm (5′-0”) depth from TWL. This chamber for the first stage is typically twice as long as it is large. The piping from the first chamber to the second chamber consists of an’ H’ shaft and the bottom of the pipe is a min. 300 mm (12) “below TWL in the first chamber and 450 mm (18”) below Total Water Level (TWL) before entering the second chamber. The drain line from the tank’s second chamber also comprises of a’ T’ shaft with the pipe’s bottom 300 mm (12) “under TWL.
From the first and second rooms, vent pipes should be built to dispose of the gases, primarily methane and hydrogen sulphide, emitted by the sludge. To order to avoid children / animals dropping into the tank, sturdy coverings should always be put entirely over a septic tank. There are many cases of falling thcovers and as a consequence, several people were killed.
Nowadays, septic tanks are constructed of GRP and polyethylene that are usually rectangular in form with a short shaft at the tip to the ground level of the manhole. These do not yield the same effluent content as two chamber tanks, and they can not be put before many conversion systems.Care should be taken to insure that complications do not arise when it is drained in high water level locations due to the tank growing out of the field. Installing the tank with a concrete lining is always recommended.
The septic tank effluent also retains approximately 70 percent of the contaminants in the initial water and needs more soakaway treatment to prevent a pollution problem.