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Wanlip Storm Inlet

Wanlip STW is Severn Trent Water’s third largest wastewater treatment facility and currently serves a population equivalent of 582,800 from Leicester and the surrounding areas. Incoming flows to Wanlip STW are split between two independent process streams; the 1960s built ‘Old Works’ treats two thirds of the flows whilst the remaining third is treated by the 1990s built ‘New Works’. Both the ‘Old’ and ‘New’ works comprise their own inlet works, storm tanks, primary settlement tanks, activated sludge plant and final settlement tanks. There is a single sludge treatment process at Wanlip STW which includes thickening, anaerobic digestion, dewatering and on-site sludge cake storage. A separate scheme has also been completed to improve and increase the capacity of sludge treatment at Wanlip which is detailed in a separate case study.

The works completed in the scheme were;

New construction and refurbishment works to Wanlip STW Inlet to reduce maintenance costs and compliance failures, improve capacity and split between old and new inlet works. Works included the construction of a new storm pumping station, new inlet channels and screens and refurbishment of existing FFT pump station with new interconnecting pipelines.


Storm Pumping Station

  • The installation of 7no storm pumps

  • The installation of 1no sump pump and the supply of all pipe work and fittings

  • The design, supply and installation of the 4no DN600 pump delivery mains, 3no DN500 pump delivery mains.

  • The design, supply and installation of the DN1000 and DN1400 manifolds  

  • Installation of all valves

  • Installation of all pump guide rails, brackets and duct foot bends

  • Design, supply and installation of all pipework support steelwork along with the access platforms, stairs, ladders, flooring and handrails

Works within the new storm pumping station included the design, manufacture, galvanising and installation of all the required support steelwork, access platforms, stairs, ladders and handrail.

The access/support steelwork had to be fitted at the same time as the new DN500 and DN600 storm pumps discharge pipework. Franklyn Yates had to co-ordinate the design and installation of the new pipework systems with the new steelwork as the pipework supports were part of the integral design of the access platforms. Co-ordinated design and installation of the two separate structures was critical to the success of the whole project.

At the same time as the new support steelwork and pipework systems were being designed and installed, Franklyn Yates had to install 7no new Sulzer storm pumps.

3no DN500 lines connected to a DN1000 common manifold and 4no DN600 lines connected to a DN1400 common manifold. Both manifolds were designed, installed and positioned outside of the main pumping station and connected to below ground pipework installed by our clients Costain.

In addition to the large bore pipework, Franklyn Yates also designed, manufactured and installed a common DN100 stainless steel washwater pipework system that feeds various different inlet screens and the hose reels around the inlet works. This included the installation of a washwater booster set complete with pumps and valves.

Grit Classifier and Grit Pumps/Pipework System

Another scope of work completed by Franklyn Yates to the inlet works at Wanlip Sewage Treatment Works was the design, supply and installation of the DN100 grit removal pipework systems. These new pipework systems connected 2no ram pumps to 3no new grit classifiers.

  • Installation of 2no Ram Pumps and associated pulsation dampers and for the design, supply and installation of all inter-connecting pipework systems, supports and bolts sets.

  • Installation of all manual valves and actuated valves.

  • Design, supply and installation of all pipe work from the detritors to the grit pumps and from grit pumps to the grit classifiers.

  • Installation of the pulsation dampers.

Wash Water Booster Set and Interconnecting Pipework

This work covered the installation of 1no wash water booster set and for the design, supply and installation of the inter-connecting pipework and supports. This runs from the existing wash water main to the booster set and then to the auto back wash water filter and then on to the 4 inlet screens, 2 storm screens and the 3 screen handling units located around the site and also included the supply and installation of 7no holes reels.

FFT Pumping Station Modifications

Franklyn Yates Engineering designed manufactured and installed the new DN600 and DN1000 scotchcoated carbon steel pipework systems within the existing FFT pumping station and installed 8 No new Sulzer pumps.

Part of the work scope included the staged removal of the existing pumps and pipework.

The removal of the old and installation of the new pumps and pipework had to be completes across three phases so as the treatment process was not interrupted and the plant continued to run.

There was also a requirement for the design, manufacture and installation of four new stainless steel baffle plates that were again installed during controlled shutdowns of the plant.

To allow the three phased shutdowns to be successful Franklyn Yates had to design, manufacture and install a temporary DN600 bypass line that required modification for the three shutdown periods, all of which were successful and completed without accident or incident.


If you would like to find out more information on the overall works completed on site you will find a useful case study on the link below

Wanlip Storm Inlet

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