Managing wastewater on your property
If you live in or rent a house that is not connected to the main sewer, then chances are that your yard contains an on-site sewage management system. If this is the case then you have a special responsibility to ensure that it is working as well as it can.
Some of the most popular types of on-site sewage management systems and provide some general information to help you maintain your system effectively. You should find out what type of system you have and how it works.
It is important to keep in mind that maintenance needs to be performed properly and regularly. Poorly maintained on-site sewage management systems can significantly affect you and your family's health as well as the local environment. Click on list of Development Control Plans What is an on-site sewage management system?
A domestic on-site sewage management system is made up of various components which - if properly designed, installed and maintained - allow the treatment and utilisation of wastewater from a house, completely within the boundary of the property.
Wastewater may be blackwater (toilet waste), or greywater (water from showers, sinks, kitchens and washing machines), or a combination of both. Greywater (sullage) can have a high percentage of the same pollutants as blackwater.
Partial on-site systems - e.g. pump out and common effluent systems (CES) - also exist.
Other systems or methods used includes chemical toilets, septic closets, composting toilets, cesspits and pans.
How does an on-site sewage management system work?
For complete on-site systems there are two main processes:
- treatment of wastewater to a certain standard
- its application to a dedicated area of land.
The type of application permitted depends on the quality of treatment, although you should try to avoid contact with all treated and untreated wastewater, and thoroughly wash affected areas if contact does occur.
Treatment and application can be carried out using various methods:
Septic Tank
Septic tanks treat both greywater and blackwater, but they provide only limited treatment through the settling of solids and the flotation of fats and greases. Bacteria in the tank break down the solids over a period of time. Wastewater that has been treated in a septic tank can only be applied to land through a covered soil absorption system, as the effluent is still too contaminated for above ground or near surface irrigation.
Aerated wastewater treatment systems
Aerated wastewater treatment systems (AWTS) treat all household wastewater and have several treatment compartments. The first is like a septic tank, but in the second compartment air is mixed with the wastewater to assist bacteria to break down solids. A third compartment allows settling of more solids and a final chlorination contact chamber allows disinfection. Some AWTS are constructed with all the compartments inside a single tank. The effluent produced may be surface or sub-surface irrigated in a dedicated area.
Composting Toilets
Composting toilets collect and treat toilet waste only. Water from the shower, sinks and the washing machine needs to be treated separately (for example in a septic tank or AWTS as above). The compost produced by a composting toilet has special requirements but is usually buried on-site.
These are just some of the treatment and application methods available, and there are many other types such as sand filter beds, wetlands, and amended earth mounds. Council or the NSW Department of Health have more information on these systems if you need it. |
