Operating in the North East of England, Northumbrian Water is responsible for the entire regions water and sewer network, serving a total population of 2.7m million covering areas including Tyneside, Wearside and Teeside.
Situated next to the river Tyne and just outside Wallsend, Howdon STW is one of the largest Sewage Treatment Works on the East Coast of the UK and treats wastewater for an estimated 1.2m population, capable of handling flows up to 10,000 litres per second of wastewater.
Recent upgrades to the treatment works resulted in a planned schedule of works to replace the main suction and discharge valves in the Primary Effluent Pump Station (PEPS), combined with the installation of a new 1400mm 5.5 tonne valve designed to control the main incoming flow to the works.
In order for these vital upgrades to take place the main inlet station required bypassing and pumping into the Aeration Primary Distribution Tanks, which distance spanned the entire treatment works.
Principle contractor JN Bentley contacted Pump Supplies after recently working together on a flood protection scheme in York city centre, to explore the best options of bypassing the inflow into the PEPS building utilising a sump with limited space whilst ensuring minimum disruption on site.
After extensive site surveys and with approval from Northumbrian Water, the agreed option was to position 8x180kW Flygt submersible N3312 pumps in an inlet sump prior to reaching the PEPS building, pumping the entire flows through a specially designed temporary network of pipework spanning a total of 1,900 linear metres around the works access roads into the Aeration Primary Distribution Tanks. The design included a specially designed pipe bridge which met highway specification and ensured normal day to day operation continued whilst the works took place.
Rob Bessant, Contracts Manager at Pump Supplies commented 'After conducting site surveys it was apparent that this would be one of the largest overpumping schemes we've seen in the UK. The potential flow rates were manageable, however we needed to ensure the pumps physical size could be situated in the identified sump. Fortunately we've got a vast hire fleet of pumps and after considering a number of options, the most efficient would be to utilise 8x180kW N3312 pumps which would sit nicely inside the confines of the sump itself, whilst achieving the duty required'.
The 3312 pumps chosen, containing the innovative self-cleaning N impeller, were an ideal option to not only meet the duty requirements, which included overcoming 35m total head, but also were able to fit the limited space available in the sump.
Installation work of the 600mm and 800mm pipework took around 5 weeks and included the fitting of £15,000 worth of nuts and bolts! The pumps, VFD's and generators were installed and commissioned by Pump Supplies specialist team of engineers.
Colin Watts, Senior Project Manager for Bentley's, commented 'After working with Pump Supplies on previous schemes we were confident they were able to deliver the full package within a tight timescale, coping with one of the largest over-pumping schemes in the UK with their vast hire fleet of not only pumps but all the pipework and ancillary equipment required to carry out this complex scheme'.
The Flygt N Pump, with the self-cleaning N-impeller technology, forms the core to the Pump Supplies hire fleet offering, and is extensively used by all the UK's water authorities. The impeller works in combination with the volute and insert ring to provide continuous high efficient pumping and is available to suit many installation types and configurations.
Paul Black, Northumbrian Water project manager, commented 'We were absolutely delighted with the result from the project itself. The scheme was delivered in budget, on time and with minimal disruption on site. We were very pleased working with both JN Bentley and Pump Supplies, combining experience & knowledge to deliver the best solution to Northumbrian Water'.back to case studies