The plant treats water from two separate sources, one for surface water from the surface of a lake and the other for groundwater from the well fields. It is the only municipal drinking water plant owned and operated by the county and has the capacity to process of 84 million gallons per day (mgd) for over 350,000 residents, with up to 30 mgd treated in the separate groundwater treatment basin.

The actuators control the flow of surface water in and out of the membrane system. This includes water coming in to be filtered, clean water flowing out to be used for drinking water supplies and clean water flowing in in order to clean the membrane. The UF process removes particles from the water in order to make it fit for human consumption. It has the capacity to process 52 million gallons of water per day.

The installation is a marked success for Rotork, as it holds the distinction of being the largest planned UF retrofit project in US history. The project includes refinements to the existing pre-treatment system, the addition of pre-screens, replacement of media filters with 12 immersed UF trains, and addition of ancillary systems including Clean in Place (CIP) system, neutralisation system, backwash system, air system, and chemical feed and storage systems.

Rotork’s actuators were selected for this project due to their high duty modulating cycles. K-TORK actuators have a torque output of up to 18,300 Nm (155,000 lbf.in) and provides precise modulating control for quarter-turn control valves with an accuracy of 0.25%. Capable of millions of operations at fast cycle times, their low friction, dual opposed lip seals ensure an extremely long operating life.

Rotork’s long-standing history with UF membrane installations made them an ideal choice for this project.