Waste & Wastewater Management

There are specific rules governing the placement and installation of septic tanks.


1.    Modern Pre-treatment Systems - A “pre-treatment” system is the first stage in


handling household waste flows before discharge to land. Modern non-flush toilet systems for dwellings without water closets include:

  • VIP toilets (ventilated improved pit)
  • Composting toilets
  • Dehydrating toilets

Non-flush toilet systems require a “greywater” septic tank and soakage system to handle kitchen, bathroom and laundry wastewaters.

2.    Modern pre-treatment systems for full waterborne wastewater servicing (flush toilet “blackwater” plus kitchen, bathroom and laundry flows) include:

  • Aerobic treatment plants (aerated systems and bio-filter systems)
  • Advanced septic tank and sand filter (or fabric filter)
  • Advanced septic tanks (larger tanks with special effluent outlet filters in place of an outlet tee)

3.    Modern Land-Application Systems - A range of soil treatment systems is now available in situations where trench systems are not suitable. These include:

  • Dripline irrigation systems.
  • ETS beds (evapo-transpiration-seepage)
  • LPED trenches (low-pressure-effluent- distribution)
  • ‘Wisconsin Mounds’ for boggy areas or thin soils over rock or high groundwater;
  • ETS, LPED and Mounds use the soil to treat advanced septic tank effluent in a far more effective way than traditional septic tank and trench systems. Dripline systems disperse high quality treated wastewater into garden areas where advantage can be taken of the nutrient and water value of the effluent.
  • Usually the most environmentally effective on-site wastewater system comprises either an aerobic treatment plant, or a sand filter treatment plant, both of which produce high quality effluent for use in supporting plant growth in landscaped areas via dripline irrigation.
  • Septic tanks require ample topsoil and organic matter to enable bacteria to break down septic tank effluent and allow the water in the effluent to soak away effectively. The soil provides the majority of the treatment in a septic tank and soakage trench system. Poor soils result in system failure.
  • The treatment process in an aerobic treatment plant or sand filter system breaks down most of the waste matter and creates nutrients for plant growth. The soil is the least important part of the treatment process, but captures bacteria and viruses to allow them to die off with time.
  • Engage a Designer - A “designer” will arrange an investigation of your site, its soil conditions and natural drainage patterns, and then discuss with you where you would wish to locate your dwelling and other on-lot facilities. Check with your local Council as to “designers” operating in your locality.
  • Applying for a Building Permit for Your On-site System - Your “designer” will also find out what your local District Council requirements are, and check if your Regional Council has set any special environmental requirements for on-site systems when installed in your locality.
  • Using an Alternative Technology System - If you decide to go with one of the alternative technology systems now available, check with your designer as to its suitability for your site. Make sure you ask about the system’s performance record, and if appropriate, ask the supplier or installer for a performance guarantee over the first three years of use.