Aerated Water Treatment System


An aerated water treatment system, or AWTS, is designed to treat sewage and other household wastewater onsite. AWTSs are purpose-built to suit your home and property, and allow you to treat and utilise wastewater if you live in a rural or otherwise unsewered area.


AWTSs consist of several treatment chambers that are ultimately attached to an irrigation system.

Household wastewater is first treated in a chamber reminiscent of a traditional septic tank. After solids and scum are separated from the remaining wastewater, the liquid passes into a second chamber, where it is mixed with air in order to encourage bacteria to treat it further.

A third chamber provides treatment for solids, which are then either returned to the septic tank for further treatment, or sent to the aeration chamber. Clarified effluent is then disinfected in a final chamber before being used for irrigation.

Not all the solids in the first chamber will break down, and so it must be periodically pumped. To find out how often your AWTS should be pumped, talk to your service technician. We will also indicate on the service report if we notice that the levels are rising and the system will need pumping out, so you have advance notice before this is required. We will also send a quote for having your system pumped out and refilled with water with one of our technicians onsite, making sure everything is done correctly.


Before you can get an AWTS, you will need to get local council approval, or, if it's a larger unit, you will need approval from the Environmental Protection Agency.

AWTSs require quarterly servicing by an approved contractor. Bioworx is an approved contractor for many city and rural councils in Queensland. To see if we're registered for your area, check out the council list on our About page.

Your AWTS should be fitted with an alarm that will indicate if the system is experiencing mechanical or electrical malfunctions.


Use and maintenance will affect the effectiveness of your AWTS. The following lists outline best practices and what to avoid. 


  • Get your AWTS inspected and serviced quarterly by an approved contractor
  • Ensure your regular service includes an assessment of sludge and scum levels (in all chambers), an assessment of the performance of irrigation areas, and a test of your disinfection chamber to ensure correct disinfectant levels
  • De-sludge your tanks approximately every three years (consult with your service technician)
  • Clean out your grease trap (if installed) at least every two months
  • Keep a record of pump outs, inspections, and maintenance
  • Learn the location and layout of your AWTS and the land application area
  • Use biodegradable liquid detergents, such as concentrates with low sodium and phosphorous levels
  • Spread laundry loads out to allow treatment time within the system
  • Keep the land application area well-maintained

  • Put bleaches, disinfectants, whiteners, nappy soakers, or spot removers in large quantities into your AWTS via the sink, washing machine, or toilet
  • Allow foreign materials such as nappies, sanitary napkins, condoms, and other hygiene products to enter the system
  • Use more than the recommended quantities of detergents
  • Put fats, oils, or food waste down the drain
  • Switch off power to your AWTS, even if you are going away on holiday (aerobic bacteria require an oxygen supply at all times)


We recommend you use the Natures Organics product range, as these environmentally-friendly products are suitable for an AWTS. All Natures Organics products are manufactured according to strict environmental guidelines, and involve no animal testing or products.