The Wanlip Sludge Project: from optioneering to commissioning of a new 28,000t/a acid phase digestion plant
Lewin, I.1, McGregor, I.2, Van Brummelen, S.2 1MWH, 1MWH, 2Costain, 3Severn Trent Water
(free)
Abstract The sludge works at Wanlip STW, a 660,000 p.e. treatment works serving the city of Leicester, was due for an upgrade as the existing assets were under capacity and life expired. Several options were considered by the project team – a consortium between Severn Trent Water, Costain and MWH – as part of the collaborative E5 alliance, and ultimately the solution developed included mechanical primary and SAS sludge thickening, Acid and Gas phase digestion, and sludge dewatering. The new works was to generate 30% additional biogas and compared to the existing installation, and to provide 100% of the site electricity. Lessons learnt from other Severn Trent Acid Phase digestion projects were available to be included in the design of Wanlip sludge works. The 28,000 t/annum sludge works is now processing all of the works indigenous sludge and accepting imports from a range of satellite sites. This paper will present the options considered for the replacement of Wanlip sludge works, the main features of the design, and the commissioning data validating the design assumptions.
Keywords: Acid Phase Digestion, Commissioning, CHP, process improvements
