UP to 70 million litres of waste water per day is now flowing through a Southampton sewage works as a major environmental improvement scheme reaches a key phase.

Southern Water’s £25m project to rebuild Millbrook’s waste water treatment works has seen the construction of a new treatment tank that is the length of ten buses, nearly a mile of new pipeline, and more than three kilometres of cable ducts.

In addition, 90 per cent of waste materials were either reused on site or recycled The firm says flows have now been switched on at the refurbished works, meaning up to 70 million litres of wastewater per day – from a population of 140,000 – is now flowing through the new structures.

The equipment is set to become fully operational in the autumn as testing continues.

As reported, work on the project in Western Docks got under way in June 2012.

Parts of the site have been rebuilt and the treatment process has been enhanced so that the water leaving the site meets tightening Environment Agency standards.

Workers have used around 9,000 cubic metres of concrete – enough to fill nearly four Olympic-sized swimming pools – plus 9,000ft of new cable ducts and around 11,000 tonnes of reinforcement steel.

Southern Water project manager Jon Kenrick said: “From an engineering point of view, this has been an exciting scheme to work on.

“It will have huge environmental benefits – the end result will be a much greener treatment works that will treat wastewater to even higher standards before releasing it into the Solent.”