Water treatment at the touch of a button

Water treatment at the touch of a button


Festo quarter turn actuators, DAPS

'One touch' control water treatment plant processing 20Ml per day at Kwazulu Natal.

The original tender for the plant specified semi-automatic operation but with the new Festo system, the water treatment plant can be fully automated with a minimum of additional time and cost. “Working on a new plant is naturally easier as we can plan the automation from design phase,” explains Brett Binnekade, Festo System Engineer. “However, automating an existing installation to a similar level of control is still possible."

In this project, the requirement was for minimal maintenance and maximum ease for control of the plant operations. The turnkey solution from Festo provided “smart” valve banks for the plant filters installed in 5 filter control kiosks. A total of 8 Festo PLCs networked together ensure that the plant is fully automated on an Ethernet network, with less cable runs and easy data acquisition for SCADA control. “Each filter has a PLC and Festo CPX-MPA valve terminal for automatic backwash cycling whilst the high-lift pumps and chemical dosing are also controlled by Festo PLC’s” says Binnekade.

Ensuring that the installation was problem free, all valves and actuators were assembled and tested at the Festo system’s workshop before delivery. A selection of the Festo range of quarter turn actuators, DAPS, were used for this project as they are specially tailored to the requirements of the process industry. The torque on these are generated via a scotch yoke mechanism, which helps to overcome the valve's high breakaway torques and confirmed to the project tender document specifications.

Automation for the main plant is controlled by 3 Festo CPX PLCs. This modular electrical terminal delivers fast troubleshooting thanks to an extensive selection of LEDs (some of which are multi-coloured) on the bus node and on all I/O modules. The entire plant is operated from the control cabinet with a MIMIC panel and SCADA system, all supplied as a turnkey project by Festo.