Darwen WwTW & Clarence Street UID`s, Lancashire

This project was carried out by Donegan Civil Engineering direct for United Utilities.

The scope of works involved the construction of a 15.00m diameter shaft, sank by caisson, approx 15m deep which will act as a detention tank / pumping station with over 1,000m3 capacity for foul water.

The detention tank was then fitted out with 2 storm pumps and a scavenger pump that would feed into a set of twin 200mm diameter rising mains approx 200m in length.

Also a 12.50m diameter shaft was underpinned, to a depth of approx 10m, around an existing 4.00m diameter tunnel to act as an CSO chamber within which a powered screen was installed.

There was also approx 500m of opencut gravity sewers ranging from 450mm to 750mm diameter upto a depth of 4m, along with a number of manholes, insitu RC chambers and finally an outfall structure that was built within the embankment of the river.

General Civil Engineering, Reinforced Concrete Structures, Segmental Shaft Sinking