ABSTRACT
The feasibility of recycling lter backwash water and alum sludge generated from water puri- cation plants has been investigated. Actual wastewater and alum sludge used in this study were collected from a water plant employing water treatment processes including chemical addition, mixing, occulation, clarication, ltration, and chlorination. Wastewater and sludge are generated mainly from the clarier and the lter backwash. The waste recycle system presented here consists of (a) recycling the lter backwash water to the intake system for the reproduction of potable water, (b) dividing the combined sludge into two fractions for alum solubilization, separately, in an acid reactor and an alkaline reactor, (c) removing the inert silts from alum solutions by two separate water-solids separators for ultimate disposal, and (d) returning the solubilized alums from the two separate water-solids separators in proper proportions for reuse as occulants.
