The concentration of manganese leaving the treatment works is usually considerably lower than the value that would cause the water to be coloured. However, manganese can be the cause of customer complaints of discolouration due to events in distribution. It is not clear which mechanisms are important in this process and which parameters determine the timing and severity of the events.
This project is developing models of the deposition of manganese on pipe walls and its later erosion and suspension in the flow. The factors that control these processes (e.g. water quality parameters, pipe surface condition) will be considered as parameters within the models. The central part of the work programme will be the development and validation of the models using test rigs sited in the supply systems of participating organisations.
The output will include:
- Mitigation measures to avoid manganese deposition and/or its re-suspension in water.
- A risk-based strategy for implementing the models for manganese deposition, erosion and suspension in water pipes.
- Procedures to reduce the risk of discolouration due to manganese and hence reduced customer complaints due to discoloured water.
- Data to demonstrate the need for investment in strategies to minimise manganese incidents.