FEATURE u Pumps & Pumping Systems


SEEPEX back-mixing technology increases sludge throughout


SEEPEX-engineered solution encompassing progressive cavity pumps for dewatered sludge back mixing has increased sludge throughput at Anglian Water’s Cotton Valley


A


nglian Water is the largest water company in England and Wales by geographic area, supplying water and


recycling services to over six million domestic customers, processing over 142,000 tonnes of dry solid sewage sludge in 2020-21 to generate 115GWh of bioenergy. The Cotton Valley Sludge Treatment Centre (STC) is one of Anglian Water’s ten main STCs where sludge is dewatered and treated anaerobically to produce bioenergy. In 2008, an advanced digestion Thermal Hydrolysis Process (THP) was commissioned to speed up the anaerobic digestion process. As part of an upgrade, a sludge-handling facility was designed to handle about 160 tonnes a day of imported dewatered sludge from satellite works. Progressive cavity (PC) pumps (not SEEPEX)


were installed to back mix the dewatered sludge and pump it into the THP. The two pumps were costing about £100k per annum due to regular 3-6 monthly change of rotors and stators. Their inability to transfer no more than 3.5m3


/h


(bottleneck and limiting gas production) meant the site was not able to meet the criteria limiting the amount of imported raw cake being handled to only 120 tonnes per day. Additionally, prior to maintenance, the silo had to be emptied to allow the pumps to be worked on, but also cake imports from satellite sites had to be diverted whilst work was carried out, resulting in substantial logistical costs. SEEPEX was invited to survey the site based on its experience in pumping and mixing dewatered sludge within Anglian Water’s water- recycling treatment sites and sludge treatment centres.


CUSTOM-MADE SEEPEX prepared a complete turnkey package that included the removal of the existing pumps, which were installed under a 7m high silo. The new pumps required custom-made hoppers, 5m long to fit under the existing silo, and had to handle 5.5m3


/hr of 16% DS sludge that had


been back-mixed within the pump from 25% DS, and transfer it about 60m. Part of the SEEPEX solution was to offer standardisation of pump size with other sludge treatment centres within Anglian Water, resulting in commonality of spare parts.


SEEPEX installed two custom-made pumps


from its BTES range with a dimensionally- identical hopper to fit within the same footprint


30 June 2021 Irish Manufacturing SEEPEX UK www.seepex.com www.irish-manufacturing.com


of the original pumps whilst delivering over 55% increased throughput capacity from 3.5m3 5.5m3


/hr to /hr.


Due to the complexities of replacing the existing pumps and the restricted space, the SEEPEX team carried out 3D modelling of the working area to ensure the pumps fit first time. Over a two-week period, the old pumps were removed and the new pumps installed all within the agreed project timeline. Prior to the installation, Anglian Water


was processing about 120 tonnes per day of imported sludge cake with both pumps running. With the new pumps installed, the customer can now exceed this by 50% (from 120 to 180 tonnes) whilst maintaining the same footprint and motor size. The new SEEPEX pumps offer ample flexibility


Pumps from the SEEPEX BTES range handle highly viscous to semi-solid products from silos


to meet the site’s production demands at lower speeds, which has a direct impact on reducing the consumption of spare parts. Since the pumps have been installed, no spare parts were needed, and the service life was considerably longer than that of the previous pumps.


RELIABILITY AND PERFORMANCE “Due to the reliability and performance of the new SEEPEX pumps, there is an increase in uptime of the cake import facility at Cotton Valley, which not only allowed us to increase the sludge throughput on site and therefore generate more biogas, but gave us significant savings in logistics and raw cake storage costs,” said Luke Fish, Production Manager at Anglian Water.


“Thanks to the capabilities and proven


expertise of SEEPEX in cake pumping, installation and management of turnkey projects, we were able to deliver a complete engineered solution for Anglian Water from the initial consultation, site survey, start up and commissioning to continued after sales and service support,” said Leigh Thornley, SEEPEX Engineer.


SEEPEX’s custom made 5m long pumps installed under existing silo


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44