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Problem No.1 Alum Coagulation An alum dosage of 125mg/l is required to treat 50 MGD of raw water in a water treatment plant. The influent suspended solids concentration of the raw water is 15mg/L. Calculate the following: a) The gallons per day of wet sludge which is concentrated to 2% by weight. (Assuming specific gravity is 2 ). b) The un-hydrated lime so that no alkalinity is consumed. The chemical reactions involved are