Septic systems consist of 3 distinct components:
- Inlet drains which transfer wastewater from your house to the septic system.
- The wastewater is then treated by bacterial action within the septic system, and solids are removed from the waste.
- A disposal system disposes of treated liquid waste from the septic tank within your property, usually via subsoil absorption or surface/sub surface irrigation. Buildings, vehicles or livestock cannot impede on this disposal area.
Types of septic systems
In Casey, the most common domestic on-site wastewater management systems (septic systems) are:
- conventional septic tanks
- mechanical treatment plants
Conventional septic tank system
A conventional septic tank system (or primary system) is made up of a septic tank and a series of soil absorption and/or transpiration trenches. All wastewater enters the septic tank. The solids settle to the bottom and are retained in the tank, forming a sludge layer, while fats and greases collect at the top known as a crust.
Mechanical treatment plant system
A mechanical treatment plant consists of a large tank with several treatment compartments:
- the first is like a septic tank
- the second mixes air with the wastewater to assist bacteria to break down solids
- the third allows for settling of solids
- the last disinfects through chlorination or UV saturation
Wastewater from treatment plants is of higher quality than conventional septic tank systems. It is disposed through absorption and/or transpiration trenches, surface and sub surface irrigation.
Sand Filter Septic System
A sand filter system consists of a large, generally subsurface structure filled with sand. Effluent from the septic tank percollates through the sand in the sand filter and captures any remaining solid material. This provides a good environment for bacteria to digest wastewater and reduce pollution. Once treated in the sand filter, the effluent is disposed into underground trenches, or sub-surface irrigation systems or another approved method. Sand filter systems are an extremely effective method for reducing risks to the environment and for increasing wastewater disposal options.
- To read more about septic systems and how they work, see our fact sheet Household septic tank system - Information for property owners.
- If you are considering purchasing a new septic system, our fact sheet Septics and Wastewater Treatment Systems will help you to select the right type for your property and to get approval from us.