Veolia completes Durban Heights Water Works filter valves upgrade

Recent component upgrades to Umgeni Water’s Durban Heights Water Treatment Works by Veolia Water Technologies, South Africa, will 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.  

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. 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.    

The project was planned to have minimal effect on the plant’s operation capacity and production while upgrades were carried out. Valve replacement was done in sections of six filters at a time, which ensured no untoward effect on the remaining filters while operations to the upgrade were carried out. New local distribution boards (DBs) will be installed and some existing DBs modified to enable the operation of the electrical actuators.  

“Due to the high demand on the Durban Heights Water Treatment Works for continued water supply,” explains Mogadima, “Veolia ensured that the maximum amount of work was carried out while the plant remained operational, thereby reducing the amount of time the filters need to be shut down.”