A sustainable option for residential wastewater

Wherever there is no main sewer, generally in rural or remote areas, there is a need for an alternative system to deal with residential human waste. There are many companies offering an individual residential wastewater treatment system, with dozens of systems appearing on the state-approved lists (including septic tanks, aerated wastewater treatment systems and sand filters). The new kid on the block is Orenco Systems Incorporated’s AdvanTex which, whilst new to Australia is well tested with over 20,000 systems installed across North America, New Zealand and parts of Europe since its launch in 2000.

The AdvanTex is a recirculating textile packed bed filter, using an attached growth technology. Packed bed filters, such as Orenco’s AdvanTex (AX20) Treatment System, use centrifugal pumps that run a few minutes an hour to periodically pump effluent (clarified wastewater) to a bed of treatment media. The system uses hanging sheets of synthetic textile as the media. Microorganisms living on the media digest the organic matter in the effluent, providing treatment. Because aerobic (oxygen-using) organisms are responsible for most of the treatment, the media must have an adequate supply of oxygen from the air.

The system takes in air through a vent. Normal air movements provide the circulation, so the system requires only enough electricity to run the pump intermittently.

The quality treated effluent (biochemical oxygen demand <10mg/litre and total suspended solids <10mg/litre) is returned to the groundwater or used for garden irrigation via sub surface drip or shallow drain. The process provides 65% removal of nitrogen (up to 75% in denitrification mode) and other advantages including: no noise, low power usage, no smell, fewer maintenance visits, infrequent pump-outs (8-12 years) and a small footprint. The system is lightweight and is predominately installed completely below ground, with green access lids all that is visible.

Options for tertiary treatment can be added where a higher class of effluent is required in sensitive areas. Unlike many other systems, which use chlorine or a UV system in the line that pumps to irrigation, Innoflow and Orenco have developed an approach using a gravity-flow UV bulb for chemical-free, consistent-contact disinfection.

There is also an option to include an around-the-clock remote telemetry monitoring system, supervised by Innoflow or its local approved service provider.

The AX20 has undertaken rigorous testing to the revised AS/NZ1546:2008 standard and is currently approved in NSW and Queensland, with Western Australia and Victoria to follow shortly.