Question

what is septic tank how does it function

Answer 1

Everything that goes down any of the drains in the house (toilets, showers, sinks, laundry machines) travels first to the septic tank. The septic tank is a large-volume, watertight tank which provides initial treatment of the household wastewater by intercepting solids and settleable organic matter before disposal of the wastewater (effluent) to the drain field.



FUNCTION OF THE SEPTIC TANK
While relatively simple in construction and operation, the septic tank provides a number of important functions through a complex interaction of physical and biological processes. The essential functions of the septic tank are to: receive all wastewater from the house separate solids from the wastewater flow cause reduction and decomposition of accumulated solids provide storage for the separated solids (sludge and scum) pass the clarified wastewater (effluent) out to the drain field for final treatment and disposal.

Primary Treatment
As stated, the main function of the septic tank is to remove solids from the
wastewater and provide a clarified effluent for disposal to the drain field.
The septic tank provides a relatively quiescent body of water where the
wastewater is retained long enough to let the solids separate by both
settling and flotation. This process is often called primary treatment and
results in three products: scum, sludge, and effluent.

Scum: Substances lighter than water (oil, grease, fats) float to the top,
where they form a scum layer. This scum layer floats on top of the water
surface in the tank. Aerobic bacteria work at digesting floating solids.

Sludge: The "sinkable" solids (soil, grit, bones, unconsumed food particles)
settle to the bottom of the tank and form a sludge layer. The sludge is
denser than water and fluid in nature, so it forms a flat layer along the
tank bottom. Underwater anaerobic bacteria consume organic materials in the
sludge, giving off gases in the process and then, as they die off, become
part of the sludge.

Effluent: Effluent is the clarified wastewater left over after the scum has
floated to the top and the sludge has settled to the bottom. It is the
clarified liquid between scum and sludge. It flows through the septic tank
outlet into the drain field.

Answer 2

Septic tank area suitable where there is no sewerage system for ,hospital, isolated building or a cluster of four-to-five house is called septic tank