Water & Wastewater Treatment Magazine
Issue link: https://fhpublishing.uberflip.com/i/851629
Going undercover ● Situated in a built-up area of north London, Deephams Sewage Treatment Works was built in its current form in the 1950s; up to 4000 local properties have been aff ected by the site's odour in the past ● Thames Water is upgrading the site to expand its capacity and modernise its treatment processes, and has agreed with Ofwat and the local authority that it will meet much-improved standards ● The new standard requires the area most aff ected by odour to comprise only 32 properties, a reduction of 99% since the baseline of 2010 The Works CHALLENGE JAMES BROCKETT EDITOR WWT Thames Water is using a combination of covers, air ltering technology and monitoring in order to ensure it meets challenging odour control targets in its upgrade of Deephams Sewage Treatment Works in north London. The utility is spending around £24M on the odour control component of the £250M project, which is expected to be completed next year. As a result of both its agreement with Ofwat and the planning process with the London before work started; the project is being delivered by a joint venture made up of AECOM, J Murphy & Sons and Kier. With Deephams situated in a built- up area, odour impacts are of primary concern for local residents and this was re‹ ected in the conditions imposed by the planning process. The key metric for the odour control work is to reduce the number of properties where residents experience odour higher than 5 European odour units per cubic metre (OEu/m3). This is applied on a 98th percentile, one- hour basis – in other words, odour levels are measured as an average over the course of an hour, and only count if they are experienced for more than 2% of the time in the calendar year. The rst component of the odour The primary settlement tanks at Deephams STW have been fi tted with PVC roof covers on aluminium trusses 14 | AUGUST 2017 | WWT | www.wwtonline.co.uk borough of En eld, Thames has committed to reducing the number of properties in the area most a— ected by odour from over 3,850 properties to just 32 – a reduction of more than 99%. One of Thames Water's biggest projects of recent years, the Deephams upgrade involves the replacement and modernisation of the entire wastewater treatment stream, while the plant remains operational throughout. It is being carried out in order to meet more stringent Water Framework Directive discharge standards, to replace existing assets that are nearing the end of their life, and to build capacity to cope with future population growth and climate change. The upgraded plant will serve a population equivalent (P/E) of 941,000, compared to 885,000