Septic tank

Septic Tank

A septic tank is part of a small-scale sewage treatment system often referred to as a septic system. Septic systems consist of the tank itself and leach field. Wastewater enters thetank where the solids settle and the scum floats

Anaerobic digestion occurs on the settled solids, reducing them. Excess liquid drains from the relatively clear portion of the tank into the leach field where the remaining impurities naturally decompose. A piping network, often constructed in a stone filled trench, distributes the wastewater throughout the field with multiple drainage holes in the network.  Wastewater is eliminated through percolation into the soil, and eventually taken up through the root system of plants or added to the groundwater

The size of the leach field is proportional to the volume of wastewater and inversely proportional to the porosity of the leach field. The entire septic system normally operates by gravity. However, in some areas where the system would be located higher than the plumbing system, a lift pump is needed

Waste that does not decomposed by anaerobic digestion eventually has to be removed from the septic tank, if not, the septic tank fills up and waste water discharges directly into the leach field. Not only is this is bad for the environment, but could prove costly as well