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Onsite sewerage systems

Onsite sewerage systems

A large number of properties in the region are not connected to a reticulated sewerage system. The treatment and disposal of all wastewater generated on these properties must be undertaken by an onsite sewerage facility that stores, treats and disposes of household wastewater on the property. Poorly sited or maintained onsite sewerage facilities can impact public health and the environment. The owner of the facility is responsible for ensuring the system is maintained and functioning properly.

For more information visit the Department of Housing and Public Works website.

  • Types of onsite sewerage systems

    Treatment systems for household waste include:

    Septic tanks (primary treatment)

    • All-waste septic tank (all household wastewater).
    • Black water septic tank (toilet, urinal and bidet wastewater only).
    • Greywater septic tank (sullage wastewater only).

    Conventional domestic sewage treatment plants (secondary treatment or better)

    • Activated sludge system.
    • Biological trickle filter system.
    • Extended aeration system.
    • Aerated/aerobic sand filter system.

    Composting systems

    • Dry vault system (toilet waste only – waterless).
    • Wet system (all household wastewater – may be considered a domestic sewage treatment plant.

    Holding tank

    • Off the premises by collection from a holding tank by a council-approved liquid waste carrier.
    • Greywater treatment/diversion facility.

    Although the installation of an onsite sewerage facility must be approved, the treatment system itself will require product approval from the Queensland Government or demonstrated compliance with a manufacturing code or Australian Standard before it is approved.

  • Types of land application areas

    A land application area is the designated area on a property for application of the treated effluent and includes:

    Irrigation system

    • Surface irrigation (spray above ground).
    • Sub-surface irrigation (drippers in shallow trench – large surface area).
    • Covered surface irrigation (drippers on natural ground covered by mulch, woodchip etc. – large surface area).

    Evapotranspiration-absorption trench/bed/mound

    • Trench or bed (embodies the principles of evaporation, transpiration and absorption).
    • Elevated sand mound (specially constructed on natural ground level).
  • Greywater

    Greywater is waste water from the bath, shower, hand basin and laundry that can be diverted for reuse on lawns and gardens. Kitchen waste water is not greywater suitable for reuse, as grease and oil can clog irrigation systems and build up on soil surfaces.

    Under the Queensland Plumbing and Drainage Act 2002, residents in sewered areas may use greywater by means of:

    • manual bucketing
    • connecting a flexible hose to a washing machine outlet
    • installation of greywater diversion devices (with council approval) and treatment plants by licensed plumbers, connected to an irrigation hose
    • surface or sub-surface system (with council approval)

    Care should be taken if reusing greywater as it can have potential health risks to humans and has the potential to damage soil, ground water and waterways by increasing nutrient and chemical levels.

    Council approval is required before installing either a greywater diversion device, which diverts greywater from the bath, shower, hand basin and/or laundry to an irrigation hose (untreated greywater cannot be stored) or a greywater treatment system that collects the greywater and treats it to a high standard for reuse as garden irrigation.

    Council approval is not required for manual bucketing or connecting a flexible hose to a washing machine outlet.

    Greywater information for plumbers/drainers

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