Recent upgrade work to Umgeni Water’s Durban Heights Water Treatment Works is set to extend the longevity of the plant by 30 years.
The project, which began in May 2013 and was valued at approximately R16.3 million, comprised the replacement of the pneumatically-actuated valves on 66 filters across three plants with new high-quality electric-actuated valves, which will enable the plant to again function efficiently. Undertaken by Veolia Water Technologies, South Africa, each plant has its own filter type, Candy, Candy Moore and Aqua Aid. The new local control panels were installed on all 66 filters across the three types in their respective plants.Lowering long-term operational costs
In addition, the backwash piping header in the Aqua Aid plant was replaced at the same time as the valves. While the rationale behind replacing the valves is wear – most were originally installed when the plant was built – future maintenance will be positively affected, lowering long-term operational costs. “Replacing pneumatic actuators with electric ones reduces the need for pneumatic piping, compressors and tanks to store the compressed air,” explains Veolia Business Development Manager Thabo Mogadima. “This process, therefore, eliminates a large amount of equipment which usually requires maintenance related to compressed air filtration.The existing programmable logic controller (PLC) has been retained for the control of the electric actuators, made possible through a few modifications to the PLC coding only.
New local control panels are installed on each of the 66 filters and all valve position feedback will be monitored by both PLC and SCADA (supervisory control and data acquisition), improving overall plant reliability.