Water and the Circular Economy
Project Round
Project Number
611 - 001
Research Organisation

Verifying Microbial Safety in Biosolids Treatment

The Challenge

Microbial pathogens present in solids recovered from water treatment works present a potential health hazard which can prevent use of this otherwise valuable nutrient material. This project examines the most common microbial pathogens present in sludge from metropolitan and rural waste water treatment plants in Victoria. The results of this examination are expected to provide the basis for a revision to the Victorian Biosolids Treatment Guidelines leading to a wider commercial use of biosolids.

The Project

Examination of the die-off of microbial pathogens in field plants and the status of their accompanying indicators during biosolids treatment will be used to validate laboratory simulations. Laboratory data will be calibrated against pathogen die-off, based on the inverse relationship of dry solids content to E. coli survival during air-drying. This validation will include the most common bacterial pathogens, viral pathogens and enteric parasites present in Australian sludge.  The results of this project are expected to underpin the revision of the current guidelines for obtaining T1, T2 and T3 treatment grades.  This proposal consists of four modules, each with a separate budget.

A literature review to establish the known prevalence of microbial pathogens in Australian primary sludge to inform a risk analysis applicable in Australia will also be undertaken.

The Outcome

The experimental results of this project are expected to form the scientific basis of recommendations for revising the definitions in the Victorian Biosolids Treatment Guidelines for Grades T1, T2 and T3.

Revision of these definitions and establishing clear regulatory guidance in producing biosolids at all treatment grades will significantly increase the commercial value and availability of treated biosolids for land fertilization applications in Victoria.

Supporting documents