A septic tank is a small scale sewage treatment system used in locations with no connection to main sewage pipe work.
A septic tank is typically 1,000 - 2,000 gallons (4000 - 7500 litres) and is connected to an inlet wastewater pipe from the property to the septic tank with an outfall pipe to a soak away.
Wastewater enters the first 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 settlement takes place with the excess liquid then draining in a relatively clear condition from the outlet into a soak away normally located under the lawn of field.