The challenge
A regional wastewater treatment plant serving a coastal city plays a crucial role in protecting the local environment and public health, with wastewater from around 93% of homes and businesses passing through its systems. One of the earliest and most important steps in the treatment process is the Milliscreen – a large rotating sieve that filters out solids larger than 1 mm before the water continues on for further treatment.
As part of a broader recovery and improvement programme, the council engaged CR Automation to complete a comprehensive risk assessment of four Milliscreens and develop an engineered safety solution to meet AS/NZS4024 machine safety standards.
Our solution
CR Automation began by conducting a detailed risk assessment across all four Milliscreens at the wastewater treatment plant. Based on these findings, CR Automation developed a Safety Requirements Specification and a Functional Description Safety document, providing the council with a clear and compliant safety framework. Once approved, the team completed the electrical safety control design and produced the safety validation documentation, ready for installation by the council and its contractors.
The resulting system achieves a minimum Performance Level PLd and interfaces seamlessly with the plant’s existing PLC and SCADA systems.
The results
The council now has a clear, validated safety architecture for its Milliscreens, ensuring compliance with AS/NZS4024 and stronger protections for operators and maintenance teams.