Typical Anaerobic Septic System
A conventional septic system depends
on a type of bacterial that can live and digest waste
in an environment that has no oxygen. Such an
environment is called Anaerobic. A byproduct is a
very corrosive, foul smelling gas that, over years of
exposure, can destroy the top and certain parts of your
concrete septic tank!
typical Anaerobic septic system is comprised of three parts:
- The conventional anaerobic septic tank that
receives the solid and liquid waste (called influent) from the house or
business that's connected to it.
- The disposal field (leach
receives liquid waste (effluent) from the septic tank. The
effluent is distributed throughout the disposal field so that it can be
absorbed into the surrounding soils.
- The soil that
purifies the effluent.
The way the three parts operate
is actually quite simple. Within the residence or business,
solid waste is put into water so gravity can move it away from the building
and into the
The conventional septic tank is designed to let
the majority of these solids settle to the bottom of
the tank. This is accomplished by retaining the influent in
the tank for several days, allowing the solids to settle
to the bottom and the water and floatable solids (scum) to
float to the top.
Intestinal bacteria from
human bodily wastes survive within the conventional septic tank and
there secrete enzymes that assist in breaking down the solid wastes
into these two forms.
By this method, 70% to 90% of the solids that
were originally put into water are removed and stored within the
septic tank, which eventually need to be pumped out
Over time, these solids build up within the septic tank
and have to be removed by pumping and disposed of off site. Typically
this means taking the contents or the septic tank (septage) to the
local municipal wastewater plant for treatment (digestion) and disposal.
clarified liquid (effluent)
flows out of the septic tank as new influent comes in, and is piped to
a disposal field.
The disposal field can be of many designs and
constructions. Most typical is the leach line, though all disposal
fields have the same function. This function is to expose the liquid
effluent to aerobic soils (with oxygen) that can absorb it.
aerobic portions of the soil, there is an abundant community of aerobic
microbes, including many species of bacteria that digest the remaining
organic matter, purify and recycle the liquid back into the environment.
The part of a conventional septic system that fails is the disposal field.