Workings of a septic tank
Septic tanks are underground tanks for sewerage where there is no connection to a large sewerage treatment plant.
Septic tanks are common in rural South Africa. They are fed black waste from toilets ( water containing human faeces, animal bloods and fats are considered black water), and in the process generate biogas which is wasted to the atmosphere. The water may be allowed to go to a soakaway, reed bed or it may need to be retained in a conservancy tank to be pumped out.
A tank costs around R1250 to be pumped out in 2013!
Septic tanks do not need grey water.
Septic tanks do not get fed wet kitchen waste.
The water leaving a septic tank is not allow to pool on the surface, but needs to drain into the ground. The can be cleaned naturally with a reed bed where the plants use the nutrients, or can drain away into a French drain or soakaway.
For more details on French drains and Septic tanks you can visit Drain Ratz Plumbing article on Septic Tanks
For more detail on Reed beds, you can visit Drain Ratz Plumbing article on Reed Beds
For further expert information on septic tanks, please follow the link to Biossystems-SA. This website explains how septic tanks are treated, maintained and repaired when there is a problem.
You can also read Cape Town's rules on septic tanks here. This article gives detailed drawings as well as designs, SABS rules and regulations governing septic tanks.