EE&T has conducted several pilot-scale investigations of membrane treatment. EE&T completed bench and pilot-scale work in which membrane backwash intended for recycle was treated as part of an AwwaRF project. Bench-scale tests focused on screening various treatments to reduce solids levels before recycling and pilot testing was used to evaluate the impacts of recycling the untreated and treated backwash stream to the head of a microfiltration (MF) treatment process. EE&T evaluated a membrane system for treatment of spent filter backwash water as part of an AwwaRF project