Proceedings

Abstract
The @one Alliance are delivering a portfolio of 28 phosphorus (P) removal schemes on behalf of Anglian Water to achieve effluents of typically 1 mg/l P. This paper presents our experiences, both good and bad, of implementing a risk based TOTEX strategy. The strategy was jointly developed by the @one Alliance and Anglian Water to deliver the schemes with the lowest capital and operational expenditure. The key challenges revolve around reducing treatment scope (i.e. treatment optimisation and avoiding tertiary treatment wherever possible), developing a standard design, challenging Anglian Water’s design manuals and minimum asset standards and optimising the supply chain by developing a standard cost model.

The paper describes the issues faced in design, installation and commissioning. It also examines the implications of P consents on sites with poor solids removal, the performance of reed beds and grass plots and sludge management. The operator’s dilemma of reducing sludge volumes by decanting and re-release of P for both primary sludge and surplus activated sludge is highlighted. The conclusions reflect on lessons learned that can be applied to AMP7.