Assessing filter robustness at drinking water treatment plants

This investigation explores the use of five‐parameter logistic curve fitting in quantifying turbidity robustness and risk scoring in clarification and filtrations stages of several surface water treatment works in the Anglian Water region of the United Kingdom. The approach taken reviews different scoring systems and addresses issues of weighting, averages and variability in robustness performance using turbidity robustness indices (TRIs). It also proposes an area‐based risk scoring profile to assess performance [relative area profile for T90 (RAP90)]. The metrics produced are considered to be a logical and rational way to help prioritise where resources for water treatment operation should be deployed.