Water & Wastewater Treatment

8 WWT PUMP AND VALVE SUPPLEMENT 2018 Case Study A new environmentally friendly and highly efficient pump from Selwood provided the ideal overpumping solution during a major flood infrastructure upgrade in a sensitive location. The S150 Super Silent electric drive, one of a new range of solids handling pumps from Selwood, provided a resilient solution for Wessex Water that minimised risk to the environment and prevented disruption to the local community. The application came as Wessex Water's engineering and construction department was tasked to make improvements to a number of sewage pumping stations as part of the Brent Knoll flood relief scheme. The village of Brent Knoll is situated in Somerset on the edge of Sedgemoor and within three miles of the Bristol Channel. The scheme included the construction of a sewage pumping station (SPS), the decommissioning of two existing stations and the refurbishment and modification of another SPS to relieve flooding issues experienced in the village. The refurbishment of Forge House SPS required the replacement of existing 50-year-old infrastructure to provide increased flows and robustness. Benching to be replaced in the wet well had to be isolated for the anticipated duration of the works. In addition, the motor control centre was being upgraded at the same time, therefore preventing the use of the existing mains supply. It was agreed that overpumping would be required to keep the SPS operating without having any impact on the local community. James Chinn, site manager at Wessex Water, contacted Selwood's framework manager, Phil Ingleheart, to request a site visit and discuss the site-specific requirements and challenges. The proximity of water courses meant that traditional diesel-driven pumping options were ruled out. Traditional electric submersible pumps were not suitable for the application because of the lack of room in the wet well. Furthermore, Wessex Water required an even quieter solution due to the proximity of residents' houses. In short, the team required a fully automated duty/standby overpumping arrangement backed up with remote telemetry that could match the pumping duty required. Selwood delivered and installed two of its S150 Super Silent electrically driven pumps. Working in partnership with key suppliers, the S150 Seltorque 30kW Super Silent pump has been developed to offer the following features: l Capable of the same performance as Selwood's 1,800rpm diesel-powered model, providing 100mm solids handling. l 310m 3 /h capacity. l 27m total head. l Variable-speed drive to ensure the correct balance between efficiency and performance depending on the application. l Suitable for multiple uses, including water and wastewater, sewage and sewer bypass and overpumping. The Selwood overpumping system was controlled by ultrasonic transducer head and variable-speed control panels, which adjusted the pump speed to match incoming flows. Ingleheart says: "By using these end suction pumps, which are even quieter than [Selwood's] industry-recognised Super Silent diesel units, Wessex Water saved time and money from having to demolish and rebuild a manhole large enough for traditional submersible pumps. "The entire control system was installed and programmed by Selwood's in-house electricians. This benefitted the client by using only the required amount of power and fuel to run the pumps. "During low flows at night this protocol significantly reduced sound output to the benefit of the local residents, while the client saved money at the same time," continues Ingleheart. "There wasn't a single noise complaint from a neighbour and this is testament to how smoothly this scheme ran." Chinn adds: "This was a really good system, which was hassle-free and backed up by automated telemetry. "The provision of live information was very reassuring for everyone involved." A robust solution for flood protection New environmentally friendly Selwood pumps provided a robust solution during a recent Wessex Water flood defence scheme

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