Rotork’s range of CVA electric actuators for control valves are designed for the exacting demands of process control, specifically in continuously modulating applications. The CVA range of linear and quarter-turn actuators offers an electrically powered process operator with high resolution and repeatability, programmable fail-to-position options, comprehensive data-logging and non-intrusive set-up and calibration in an IP68 watertight and explosion-proof enclosure. In the water and wastewater treatment industries there are many applications where the CVA actuator can assist the solution of the most demanding problems. In a typical example, a wastewater treatment facility in the USA uses a hydrothermal three-way needle valve to control the flow of steam into an anaerobic digester to maintain a constant temperature of 36.9C, utilising a controlled steam temperature at approximately 93.3C. An important requirement of the application is that in the event of a power failure the control valve must shut off the supply of steam to prevent an adverse reaction with the bacteria that treats the sludge. In addition to meeting the primary requirements of the application, the CVA also provides the benefits of a built-in data logger, enabling the periodic download of information regarding the behaviour of the valve. This data is useful in managing the operation of the digester and facilitates the scheduling of planned maintenance.