Characterization and Conditioning of Water Treatment Plant Sludge

Abstract

The objectives of this study were to: develop methods for sampling and measuring the characteristics of the alum sludge collected in the settling basins of rapid sand filtration plants; collect data on the characteristics of this sludge at a water treatment plant in order to predict the applicability of various treatment processes; and, determine whether the relationship between dosage and specific resistance of an alum sludge is a valid measure of the effect of synthetic organic polyelectrolytes on its dewatering characteristics. The two plants chosen for the study were both rapid sand filter plants treating surface water from essentially rural watersheds, impounded in plant A but not in plant B. The only chemicals added to the influent were chlorine and alum, except for small doses of active carbon added in plant A for 2 days. Rapid and slow‐mixing were followed by sedimentation in rectangular, concrete, manually cleaned basins.