Severn Trent Water treatment upgrade

Severn Trent Water treatment upgrade demonstrates Rotork Retrofit options.

New and refurbished Rotork electric valve actuators are being used throughout a major upgrade project at one of Severn Trent Water's largest water treatment works. Opened originally in the early 1900's, Bamford WTW takes water from the Derwent, Howden and Ladybower reservoirs in the Peak District to supply Derbyshire, Leicestershire and Nottinghamshire at a rate of up to 197 megalitres/day.

The £5 million project for treatment modifications, undertaken by Norwest Holst Construction Ltd, involves the refurbishment of inlet works, rapid gravity filters and lime plant, together with the installation of new washwater recovery plant, instrumentation and analysers. As an integral part of this work, Rotork's specialist Retrofit department has installed new IQ electric actuators on existing valves and refurbished sixty existing Rotork actuators on the site, as well as providing a commissioning service on the new Rotork AQ actuators that were supplied on new Saint Gobain valves.

Rotork Retrofit Site Services Manager Mike Dale explains: "Our ability to refurbish our customers' existing actuators as well as supplying new illustrates how a flexible approach can save money without compromising quality or reliability. Refurbished actuators are brought up to as new condition and usually carry the same warranties as new equipment."

A significant area of Rotork activity involves the refurbishment of 28 rapid gravity filters, including 16 that are the first in the UK to be equipped with LP block filtration systems, supplied by Tetra. New actuators on filter inlet and outlet penstocks, together with backwash, diverter and air scour valves, linked to a new Boulting Group supervisory PLC system, will increase the automatic backwashing cycle from 24 to 36 hours, improving filter utilisation and reducing the amount of washwater required. Rotork actuators are also installed on new lamella separator plant that will filter the washwater before it is returned to the treatment works. This in turn will reduce the loading on the rapid gravity filter beds, further improving utilisation and efficiency.

Rotork Retrofit was awarded the valve actuation contract at Bamford under the terms of the framework agreement that Rotork holds with Severn Trent Water. Rotork's framework is now in its second period of agreement, following the expiry of the original five year agreement.