The Septic Process

A septic system (tank and drain area) is a small scale sewage treatment system, common in areas with no connection to main sewage plants. The term “septic” refers to the anaerobic bacterialenvironment that develops in the tank and which decomposes the human waste discharged into the tank. Tanks can have additional treatment features such as aerobic systems involving air pumps that force aeration.

Wastewater enters the inlet chamber of the tank, allowing solids to settle and scum to float. The settled solids are anaerobically digested reducing the volume of solids. The liquid component flows through the dividing wall into the second chamber where further processing takes place. The liquid effluent then drains in a relatively clear condition from the tank outlet into the drain field where soils further process the water.

Regularly adding a supplemental enzyme agent to the tank may accelerate the digestion of solids and help clarify the liquid effluent disposal in the drain field.

Periodic preventive maintenance (pumping out the tank) is required to remove the irreducible solids (sludge) which settles, reducing system efficiency, and gradually fills the tank.

A properly maintained system can last for decades and possibly a lifetime. This involves having the tank cleaned out by a professional septic pumping company every few years if two people reside in the household.  If there are more residents, the tank will need to be cleaned more frequently.

Septic Systems User’s Guide