Added value:
Little Marlow STW in Buckinghamshire discharges into the Thames and enhanced discharge consents necessitated process improvements by the adoption of biological nutrient removal.

A design and build contract with a value of £21m was awarded to Interserve by Thames Water with Halcrow as the designer. 

Innovation:
The winning Interserve tender was developed using as a basis process reviews, optioneering and outline designs prepared by Halcrow.

The existing main outfall had hydraulic problems and the intention was to replace it.  However, some careful hydraulic analysis resulted in linkage of the existing storm and main outfalls avoiding the need for construction of a new outfall.

At the inlet works the need for long channels and flumes is avoided by the use of a channel
mounted magnetic flow meter.

Team work:
The design and associated development work is carried under the control of Halcrow in a team environment utilising the skills and experience of Thames Water, Interserve and Earthtech Eng.