Biosolids are the stabilised organic solids derived from the treatment of municipal sewage, and can be beneficially reused with appropriate control measures. They are widely used in broad acre agriculture throughout Australia.

The Department of Health (DOH) and the Department of Environment and Conservation (DEC) assess proposals to use biosolids. The use of biosolids will need to meet the requirements of the Western Australian guidelines for biosolids management (PDF 1.76MB) to ensure that potential impacts on human health and the environment are addressed.

The Guidelines do not apply to sludges from animal industries or untreated septic tank sludges.

Biosolids Direct Land Application

Biosolids applications of less than 1000 tonne do not require DEC approval but DOH approval is still required. Only biosolids that meet strict quality standards for pathogens and contaminants can be land-applied for beneficial purposes. 

Biosolids to Compost

Compost is further processed biosolids with lower pathogen concentrations that can be used in home gardens or lawns. The quality of the final composted product needs to be assessed to ensure the product achieves the required (P1C1) classification and therefore can be used as an unrestricted product. It means that the compost once approved is suitable for any land use application.

There is no minimum volume trigger and therefore all proposals involving the use of biosolids for the production of composts must be submitted to DOH for assessment. The requirements are listed in the Guidance on applying for approval to use biosolids in compost.

Check the DOH list of approved composters.

Related Website

Water Corporation Biosolids Program (external site).

For further information, contact the Water Unit, Environmental Health Directorate.
Phone: 9222 2000

Last reviewed: 29-10-2020