On Site Sewage Management
What are On Site Sewage Management Systems?
On site sewage management systems (OSMS) refer to wastewater systems situated within a property's boundary that treat the wastewater generated from the property and includes the land application area. These systems are required in areas that are not serviced by Council's sewerage infrastructure. OSMS may include septic tanks and aerated wastewater treatment systems (AWTS).
1. Septic Tanks
A septic tank is a waterproof tank usually located below ground level and provides treatment of sewage by allowing solids to settle to the bottom of the tank and oils and fats to float to the top to form a scum layer. Anaerobic (in the absence of air) bacterial digestion of the stored solids produces a sludge which accumulates at the bottom of the tank. The partly treated effluent flows from the septic tank to either a holding tank for regular pump out or directly to a soil absorption system.
2. Aerated Wastewater Treatment Systems
Aerated wastewater treatment systems (AWTS) use aeration of wastewater as an integral part of the treatment process. A typical AWTS treats wastewater through the following process:
- Settling of solids and flotation of scum in an anaerobic primary chamber (septic tank);
- Oxidation and consumption of organic matter through aerobic biological processes;
- Clarification - secondary settling of solids;
- Disinfection using chlorine or other approved means if surface land application of treated wastewater is to occur; and
- Regular removal of sludge to maintain the process.
There are special regulations that apply to these systems. As the owner of the property, it is your responsibility to ensure that the system is approved by your local council and that it is working properly. On site systems can be a risk to the health of your family and other community members if they are not properly maintained. They can also cause harm to the environment.
To ensure that your system meets the requirements, you will need to obtain two approvals from your local council:
- The first approval is to install the system.
- The second approval is to operate the system.
Approval to install
If you wish to install a new on site sewage management system on your property you are required to gain approval from the Council. You must submit an application to install an on site sewage management system (Application under section 68 of the Local Government Act) together with all the required information along with the application fee.
Approval to operate
The State Government on the 6th March 1998 Gazetted the Local Government (Approvals) Amendment (Sewage Management) Regulation, under the Local Government Act 1993. This amendment requires that an Approval to operate an on site sewage management system be obtained for all sewage management systems. This means that Council must issue an approval to operate for every existing on site sewage management system in the Local Government Area. Please complete the Application under section 68 of the Local Government Act form and submit it to Council.
New Home Owners - If you have recently purchased a property that uses an On site Sewage Management System, the Local Government (General) Regulation 2005 provides a period of three (3) months in which to make an Application for an Approval to operate.
After you obtain these approvals, the council will carry out inspections to make sure the system is working properly.
If you have any questions about the on site sewerage system requirement you can contact Council's Planning, Development & Compliance Department on (08) 8080 3300, or consult the Easy Septic Guide.