AWWA JAW59119

Backwash water chemistry can have significant detrimental effects on filtered water quality under some circumstances. Water utilities experiencing adverse backwash water chemistry can significantly improve water quality, protect public health, and help ensure regulatory compliance by applying the information set forth in this article. Delayed start and backwash water chemistry can range from playing a large role to having no effect on filtered water quality, depending on treatment conditions. Indeed, delayed start has been known to work well at some locations and not at others. In this article, the authors explain the details of why this technique may or may not be effective and how to evaluate what methods are most effective at a particular facility. With the insights in this article, some water suppliers will be able to make minor operational changes that will significantly improve filtered water quality from their facility. Includes 24 references, tables, figures.