Sewage risk management through collaboration

The collaboratively-developed Sewage Quality Risk Assessment Toolbox is a centralised digital platform that is streamlining sewage risk assessment processes, and ensuring decisions are supported by the best available data and knowledge. Read the case study to learn more.

Sustainable Development Goal 15: Life on land

Sustainable Development Goal 14: Life below water

Sustainable Development Goal 09: Industry, innovation and infrastructure

Sustainable Development Goals:
Goal 9: Industry, innovation and infrastructure
Goal 14: Life below water
Goal 15: Life on land


Melbourne Water, City West Water, South East Water, and Yarra Valley Water work together to manage the quality of Melbourne’s sewage.

In doing so we aim to:

  • Ensure the safety of those working in the sewers and at the wastewater treatment plants.
  • Protect the sewage pipes, pumps and other equipment.
  • Protect the wastewater treatment processes, including production of biogas by the microorganisms.
  • Comply with regulation and licence requirements including the protection of the air, water and soil.
  • Facilitate water recycling and the beneficial reuse of biosolids, which are a by-product of wastewater treatment.

A key part of this work is assessing the risk from expected changes in the raw sewage entering our sewers, which typically come as industrial trade waste discharge.

As existing methodologies are challenging to use, we identified that a more streamlined, collaborative process would help determine sewage quality risk more effectively.

Project focus

The Sewage Quality Risk Assessment Toolbox (SQRAT) is a centralised ‘single source of truth’ digital platform for assessing sewage quality risk. The platform, developed collaboratively between the four water businesses, contains a set of tools that can be used to streamline the risk assessment processes.

It also ensures:

  • easy access to the latest risk assessment methods
  • full transparency about how risk assessments are conducted
  • all risks are appropriately prioritised.


We have undertaken significant work to digitise existing methodologies and incorporate outcomes from Melbourne Water’s long-term research project, the Sewage Quantitative Risk Assessment for chemicals of concern. This has proved beneficial by compiling knowledge that was previously challenging to use into a ‘business as usual’ process that supports operational requirements.

The SQRAT is not a static system. Rather, it is modular, allowing updates or replacement of existing methods as better ones become available. This ensures that all decisions about managing the quality of sewage are supported by the best available data and knowledge.

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