Welsh Water has announced that it is investing GBP 200 million to upgrade its water treatment works across Wales by 2015. This includes the water treatment plant at Cwellyn, where Rotork intelligent electric valve actuators have been installed to control the flow through a new extension to the works. The new treatment regime is designed to clarify the water before it enters the existing works in order to deal with changing raw water conditions and consistently meet all water quality standards. Rotork IQT direct drive quarter-turn intelligent electric actuators have been installed to operate butterfly valves controlling the flow of water throughout the new treatment plant. All the Rotork IQT actuators are Profibus DP-enabled and linked to an existing distributed control system (DCS) on five two-wire bus networks. The operation of the plant is supervised by a SCADA system designed by Oasis Engineering Ltd. The Rotork IQT actuators, including some modulating units, control all valve operations including the inlet works flow control, automatic desludging of the DAF cells, automatic backwashing of the RGF plant and the plant treating the effluent created by the clarification and filtration processes. The successful completion of the upgrade project at Cwellyn will safeguard the drinking water quality for 70,000 Dwr Cymru Welsh Water customers in the Caernarfon area.