For a complete and detailed description of septic tanks / mechanical treatment systems reference should be made to the ‘2021 Code of Practice for Domestic Waste Water Treatment Systems’ as published by the EPA. This can be viewed or downloaded at the following link or in the download section of this website.
Additional information can also be obtained from the wastewater section of the EPA’s site at.
However, for clarity and simplicity, the following two images outline the general details associated with a standard septic tank and a mechanical treatment system.
Standard Septic tank arrangement – EPA
Septic tanks tend to consist of a single tank (normally of concrete or blocks) with an inlet from the house and an outlet to a percolation area. This system normally won’t have a power supply connect to it and doesn’t have pumps.
Example of a typical biological aerated filter system (Mechanical Treatment system) – EPA
Mechanical Treatment Systems can consist of a single or double tank typically constructed from either pvc or concrete. with an inlet from the house and an outlet to a percolation area. This system would normally need a power supply to run pumps, aerators, and other components.