United Utilities is on target to complete its  £200 million extension to Liverpool wastewater treatment works in Spring 2015.

The aerial photograph shows the interior of the plant at Wellington Dock, where construction began in autumn 2012- United Utilities engineers are now due to start constructing the covers later this month.,  

The company is on target to get the works operational by next spring, which will keep the River Mersey clean for future generation.

Lorne Large, United Utilities Principal Project Manager, said:

“It’s staggering to think how quickly this important building has shot up. It only seems like yesterday we were standing on the side of a water-filled dock. It’s one of the biggest construction sites in the city and means we will be able to keep the River Mersey clean well into the next century.”

The photograph also shows three of the basins being filled with water to test for leaks – all three have passed the test.

Around 350 people will work at the Wellington Dock site which will serve 600,000 Liverpudlians when it is finished.

As well as the new extension, the existing works in neighbouring Sandon Dock is being improved and a 285m long outfall pipe has been installed on the bed of the Mersey, taking the treated wastewater out into the middle of the river.

It will then hit strong tidal currents and be dispersed more widely into the estuary and Irish Sea. This will reduce the risk of pollution to the coastline and improve habitats for birds.

The project will continue the long-term aim of keeping the river clean, something which originally began in the 1980s, when it was heavily polluted and named as the dirtiest in Europe.

Since then United Utilities has spent millions of pounds on the construction of a huge 29km sewer from Crosby to Speke, which carries the city’s wastewater to Sandon Dock. Now, salmon and trout live in the river.