Darlington MP Alan Milburn will open a drinking water treatment works in Darlington today.

The Broken Scar works has undergone major improvements over the past four years, at a cost of £22m, without interruption to customers' supplies.

The works can treat up to 180 million litres a day and supplies 300,000 homes in Darlington and Teesside, plus large industrial users in the Tees Valley.

Improvements include construction of a large granular activated carbon plant to remove naturally occurring organic content in the raw water supply taken from the River Tees after release from Northumbrian Water's reservoirs in Teesdale.

Further improvements made on site include new storage and treatment facilities for chemicals used in the processes and equipment to deal with sludge removed by treatments.

Dr Colin Price, Northumbrian Water's technical director, said: "The upgrade has been carried out to ensure quantity and quality of water treatment for customers and that supplies continue to meet increasingly stringent European standards.

"We are particularly proud that all the work has been carried out without a single interruption to customers' supplies, which is a tremendous achievement," added Dr Price.

A pond and amphibian habitat retreat has been created for a colony of great crested newts, smooth newts, frogs and toads.