A septic tank performs 3 main functions;
- Acts as a settlement chamber for solids,
- Allows bacterial breakdown of waste,
- Forms a storage chamber for undigested materials (scum and sludge).
When waste passes through the septic tank a bacterial digestion process commences eating away solids and forming sludge. This sludge settles to the bottom, lighter materials such as oils, grease and fat will float to the top and form a crust (scum layer). The cleaner effluent water will remain in the centre and flow to the soakage trenches where it under goes natural processes to purify
The natural bacterial process will be affected if the scum and sludge layers are allowed to build up as this build up does not allow enough retention time for the primary treatment process to occur and solids will pass through to the trenches blocking the pores in the soil, resulting in failed absorption trenches and expensive repairs.
Sludge should not be allowed to build up more than 30 % of the total volume.
As guide for septic pump out, we recommend cleaning every 3 to 5 years. This will vary for every system.