what is a septic tank

A septic tank is an underground chamber made of concrete, fiberglass, or plastic through which domestic wastewater flows for basic sewage treatment. It is a part of a septic system, which also includes a drainfield or soil absorption field. The septic tank digests organic matter and separates floatable matter and solids from the wastewater. The liquid effluent is then discharged into the drainfield for further treatment and dispersal. Septic tanks are commonly used in areas that are not connected to a sewerage system, such as rural areas. They work by collecting excreta and wastewater in an underground tank, providing a safe disposal of wastewater for homes with poor drainage or those not connected to the mains sewage network. The treated liquid effluent is commonly disposed in a septic drain field, which provides further treatment. However, groundwater pollution may occur and can be a problem.