In non-sewered areas, septic tanks systems were once the norm. As more Councils require stringent effluent discharge quality, the installation of aerated treatment units (ATUs) is steadily increasing. These whole-house systems treat all wastes to a secondary standard and the discharge water can then be used to irrigate gardens.
ATU’s are biological systems and they require servicing and maintenance by experienced, registered service technicians. Furthermore, pumps and blowers use electricity and occasionally need replacement. All of this adds on-going costs to the overall operation of the system, but at least about 200,000L each year is used to irrigate lawns and gardens.
There are many types of ATUs in the marketplace, but typically they cost about $15,000 fully installed.