Hired technology from WCS Environmental Engineering (WCSEE) is ensuring a wastewater treatment works in Cotswolds village, England, UK maintains compliance while undergoing a refurbishment.
Blockley village wastewater treatment plant (WWTP) serves a population of 2,360 and is currently being refurbished by utility Severn Trent Water and construction contractor Galliford Try, which is managing the project.
Three WCSEE hybrid submerged aerated filter (SAF) units, with control panels and blowers, were selected to provide secondary biological treatment on a temporary basis, while two trickling filter beds were taken out of service for refurbishment.
It is said to be modular in design, with a 30% smaller footprint than other technologies. The SAF units are built off-site and can be transported easily. The process technology employs a submerged moving-bed, fixed-film reactor, proven to treat wastewater with greater energy efficiency compared to traditional submerged SAFs, and in a tighter site footprint. WCSEE utilities manager Andrew Haywood said, “Hiring mobile equipment brings utilities flexibility throughout their project. The technology can be in place for however long it is needed — weeks, months or in some cases, years — and can be removed on completion, to be returned or transported to other sites if needed. The option to hire brings reassurance for utilities who are carrying reactive, unplanned work.”
At Blockley, the units are treating a peak flow of 27.5L/sec while meeting environmental permit requirements of 15mg/L biological oxygen demand (BOD) and 2.5mg/L ammonia.
In a statement, Galliford Try project manager Luke Vardy said that they approached WCSEE early on in the Blockley scheme to produce a solution for temporary treatment requirements. “Once installed, during the seeding period we allowed a 12-week time scale. The units seeded in six weeks, saving time on the programme and allowing the refurbishment work to start sooner,” he said.
He added that due to the tight ammonia consents, the SAFs were an important part of the temporary treatment as they regularly took samples throughout the operational period to track performance. “The effluent results were stable throughout all weather conditions,” he said.
