Located north of Birmingham in the River Tame catchment, Severn Trent Water’s Walsall Wood WwTW uses Royal HaskoningDHV’s Nereda® aerobic granular sludge technology.   The former trickling filter works received AMP6 Water Framework Directive standards for phosphorus and ammonia, requiring the site to be upgraded to meet stringent standards of BOD: 10 mg/l, NH3: 1.9 mg/l, Total P: 0.5 mg/l and to consider the future population equivalent of 26,250 for the 2026 design horizon.

Severn Trent Water selected MMB as the Main contractor, - utlising Nereda® as the biological process followed by tertiary cloth filtration selected, as the preferred technologies.  This delivered the most cost-effective TOTEX solution requiring a third of the area of a conventional activated sludge installation with only two thirds of the whole life cost and carbon footprint for an equivalent water quality output.  The scheme was successfully commissioned in 2019 but since this time further optimisation has been carried out with low-P dosing trials.  These trials have demonstrated that Ferric dosing to the influent buffer to meet the TP limit of 0.5 mg/l in the Nereda® effluent, provides an 50% chemical saving compared to tertiary dosing, giving significant OPEX savings in chemicals and allowed further optimisation of the cloth filter tertiary plant.  These dosing trials provide the confidence that Nereda® can play an important role in meeting future AMP8 TP consents standards.

This visit will include a brief background talk about the project in a nearby hotel (with drinks), prior to visiting the site.

Please have an early lunch before the visit.  

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