EE&T has been at the forefront in developing treatment strategies for particle count and cyst removal from spent filter backwash water. Classification and treatment technologies designed by EE&T for backwash water include plate settlers, tube settlers, and conventional gravity clarifiers. All these facilities were further enhanced with equalization basins, variable speed pumping, and polymer treatment. Most designs incorporated flexibility to allow recycle of the backwash water or discharge under a NPDES permit. EE&T was a lead negotiator on the Federal Filter Backwash Recycle Rule (FBRR) and was asked to prepare a guidance manual for the industry on best management practices for recycle. EE&T also authored a 2001 AWWARF publication on “Treatment Options for Removal and Giardia, Cryptosporidium and Other Contaminants from Recycled Backwash Water.”