Selwood devised an innovative large-scale overpumping solution at the Swale Site of Special Scientific Interest

An overpumping solution that minimised environmental risk and maximised efficiency was provided by leading pump provider Selwood during a major project at Eastchurch, Kent.

Following months of early engagement between Selwood and its client partners, the pump solutions specialist was selected to supply and install a large-scale overpump of a wastewater treatment works across Swale Site of Special Scientific Interest (SSSI)-protected land. The challenge came as major lining works were being carried out on the existing outfall main.

The works’ location, at the Swale Site of Special Scientific Interest, a major reserve for overwintering birds, demanded an environmentally-sensitive solution. Selwood was also faced with the challenge of a tight time schedule as the RSPB and other regulators would only allow access between July and October.

Selwood’s team carried out a full on-site assessment to deliver a bespoke solution. After calculating the flows and pipeline efficiency, specialists decided the best option was to use 500mm flanged steel pipework. This reduced friction loss, resulting in reduced running costs and therefore improving the whole life cost of the scheme.

The specific pipework needed was not available in the UK and therefore Selwood committed to purchasing the necessary kit to support the scheme and, as a result, further expand its UK fleet offering. Selwood worked collaboratively with its steel supplier and its fully-trained installation teams, resulting in the seamless delivery of 2.3km of flanged pipework above ground.

A highly-bespoke pumping solution was required as flows varied dramatically, from 160 litres per second in normal flow, to 410 litres per second in storm flow. Therefore, two pumping systems were configured – 30kw pumps for the dry weather flow and a twin sync set generator set-up was configured to start and run only in the event of storm flows to power 70 KW submersible pumps. 

This innovative cost-saving approach was supported by Selwood specialists managing the flows via ultrasonic-level controls and variable speed drives. The scheme was delivered to schedule and took a total of 17 weeks.

James Sinnock, Strategic Account Manager for Selwood, said: “The risk, robustness and the efficiency of the scheme were key factors throughout this demanding application.

“Because of the site’s environmental status, it was imperative to deliver the overpumping to schedule and we were pleased the strategic approach by our knowledgeable team delivered an innovative solution for the client. Our variable pumping set-up resulted in a large-scale reduction in both the running costs and carbon footprint of the scheme.

“This was a highly successful project with Selwood and our client partners working in collaboration to achieve a positive outcome. Our drone video of the project really does capture the size and scale of the application.”