PODDS et AL
Prediction Of Discolouration in Distribution Systems &
Addressing LEMA 

PODDS et AL represents a truly treatment-to-tap approach to managing drinking water quality. In particular the research addresses the primary issue reported by consumers of discolouration. Extensive collaborative research since 2001 has shown how low-level backgound concentrations of material accumulates as layers on all pipe surfaces (PODDS) and as localised elevated material (LEMA) deposits. By determining which process dominates, and through understanding of the different behaviours, sustainable and low-cost hydraulic strategies can be successfully applied*. 

To support a transistion to self-maintaining networks, operational tools and free models and support have been made available (e.g. PODDS APP and VCDM). The recurring nature of consumer discolouration however highlights defiencies in current network design and operation. The challenge now is to show how simple adaptations can deliver benefits, including reduced network complexity together with improved resilience, disinfectant retention and ultimately customer service.

*Working with UK water companies, it has been shown discolouration can be sustainably managed by non-disruptive pro-active hydraulic conditioning. Application of the research to 2,686km of trunk mains between 2015-2020 delivered over £411m savings in operational and capital expenditure. REF 2021.