Water & Wastewater Treatment Magazine
Issue link: https://fhpublishing.uberflip.com/i/515382
14 | JUNE 2015 | WWT | www.wwtonline.co.uk Project focus A n innovative three-stage biological sewage treatment process is cutting costs and improving efficiency at Nottingham's Stoke Bardolph wastewater treatment works. The Severn Trent Water (STW) plant serves a population equivalent of 650,000 and includes a stream of difficult-to-treat trade waste from a local rendering plant. A new phosphate consent along with the need to replace ageing assets at Stoke Bardolph provided STW with the opportunity to reduce the physical footprint of the process, target improved resource recovery and allow for the possibility of future raised ammonia consents. The £6.8M system at the Nottingham plant, which replaces a conventional activated sludge process (ASP), also presented particular challenges in terms of process and control for the project partners. An early feasibility study recognised the potential of carrying out efficient pretreatment of the high- strength liquors. Severn Trent Asset Creation & Service Delivery and civil engineering, electrical and mechanical subcontractor NMCNomenca worked with Netherlands' company Paques BV to introduce three suitable and ● Innovative three-stage treatment process for Severn Trent wastewater plant ● Ammonia and phosphate removal incorporated in £6.8M project ● Resource recovery and compact installation halves operational costs complementary technologies to the site in a first for the UK. The combined use of Paques' PHOSPAQ, BIOPAQ UASBplus and ANAMMOX processes has made it possible to recover phosphate fertiliser, generate biogas and deliver efficient ammonia and phosphate removal at the site. It has also halved operational costs, made possible a 40% saving on Capex and reduced the plant's physical footprint by three- quarters. The sludge dewatering liquors from the municipal sewage stream are first treated in a phosphorus removal reactor. The trade waste stream is first treated in an upflow anaerobic sludge blanket (UASB) reactor for biogas production and chemical oxygen demand (COD) removal. The two streams are then combined and treated in an ammonia-removing reactor. Phosphorus removal The two PHOSPAQ reactors at Stoke Bardolph are the UK's first installation and only the third in Europe. The process takes place in an aerated reactor, which provides oxygen for the biological conversion of the COD. Aeration also provides optimal mixing Teresa JeffcoaT PRoJEcT MANAgER, NMcNoMENcA Wastewater treatment Phosphate and energy recovery slash costs at Stoke Bardolph A view of Severn Trent's Stoke Bardolph site from above The two BIoPAQ UASBplus reactors at Stoke Bardolph produce 3MWh/d