Skip to main content

How septic systems work

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 percolates 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.

Have you found the information you were looking for?