School operations

Wastewater Treatment Systems

Including septic tanks and treatment systems for wastewater

Disposal methods

Effluent can be disposed of either by below ground absorption or by reusing it for irrigation. The disposal method used depends on how much treatment the wastewater has received.

Wastewater treated to primary quality is only suitable for disposal below ground via soil absorption trenches, mounds and evapotranspiration beds or trenches.

Wastewater treated to secondary quality can be dispersed to land via:

  • pressure-compensating subsurface irrigation
  • surface irrigation using a network of drip, trickle or spray points to apply effluent just above the ground's surface
  • subsurface irrigation using a network of polyethylene pipes located just under the ground's surface to apply disinfected effluent in the root zone of plants, preventing airborne drift and minimising runoff
  • sand mounds above the soil surface, which can be used when typical disposal methods are unavailable
  • absorption trenches and beds, which can be used to release effluent below the surface through narrow and deep trenches, or wide and shallow beds
  • evapotranspiration absorption beds that remove water from land covered by vegetation through evaporation.
Includes information on effluent disposal methods such as below ground absorption or reuse for irrigation

Reviewed 09 January 2023

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