Profibus-enabled Rotork electric valve actuators are key components in the control system for a new filtration and treatment plant at a water source owned by the Essex and Suffolk Water Co. Mowlem Engineering & Mowlem Civil Engineering are building the new plant in order to increase the supply of high quality water to users in the Grays and Thurrock area by up to 4.5 megalitres/day. An electric pump has been installed to bring the water to the surface where it is treated and filtered to remove a high iron and manganese content before entering the supply network. The new plant comprises six pressure filters containing sand and manganese dioxide media, multiple chemical dosing stations and on-site filter backwash water processing, all under PLC automatic control using Profibus communication highways. The majority of the Rotork actuators installed are IQT units on butterfly valves controlling the flow through the filters and the sequence of backwashing operations, which is initiated either by time elapsed, operator intervention or the analogue input signal from a differential pressure sensor.
