Calculating dry weather flow (DWF) at waste water treatment works

How to calculate dry weather flow (DWF) as part of an environmental permit application or to vary an existing permit.



This guide is for operators of waste water treatment works (WWTW) that receive sewage and rainwater from combined sewers. It mainly applies to water companies and new appointments and variations (NAVs) who operate WWTW serving cities, towns and villages (agglomerations).

Published 8 May 2018