- ASpect’s Client: Orange City Council
- Head Client: Orange City Council
- Plant Configuration: MLE
- Plant Size: 60,000 EP
- Project Value: $8k (ASpect Fee $8k)
- Project Duration: May 2022 to June 2022
Orange STP Recycled Water Chlorination Optimisation, for Orange City Council (NSW).
The majority of the effluent from Orange STP is re-used for various applications at the Newmont Cadia gold mine. As such, the effluent must meet the requirements of the Australian Guidelines for Water Recycling (AGWR). ASpect was involved in a risk assessment workshop that was used to ratify the log removal values (LRVs) required for the application. It was resolved that the critical LRV was for virus inactivation, making effective chlorination paramount. The LRVs required were heavily influenced by the end use management practices at Cadia which were stringent. The conclusion was that the treatment LRV required at Orange STP could be reduced from 4 to 2 LRV for viruses. ASpect had already designed the control system for the Orange STP chlorination system, including all the critical controls required. An independent review of the system suggested some enhancements. The control system was modified to include these enhancements. ASpect also devised a spreadsheet tool to help the Orange STP operators to explore chlorine dosing options. Inputs included the virus LRVs required, the draw off point within the chlorine contact tank, critical limits on effluent flow, recycled water flow, pH and turbidity. The outputs included the free chlorine residual (FCR) critical limit ot each monitoring point. This allowed the operations staff to reduce chlorine dosing, reducing the risk of exceeding chlorine discharge limits, while maintaining the LRVs required for the recycled water application.
