The Philadelphia Water Department (PWD) has established an ambitious goal of 0.015 mg/L total manganese concentration in the finished water, well below the secondary maximum contaminant level (SMCL), to eliminate any potential for aesthetic problems related to manganese in the distribution system. It is generally accepted that the powerful oxidizing potential of ozone is sufficient to control Mn. Pilot studies at two of PWD's water treatment plants demonstrated that ozonation cannot consistently reduce manganese to PWD's internal goal of 0.015 mg/L. By contrast, adsorption on oxide coated filter media and contact oxidation at relatively low free chlorine concentration dramatically outperformed intermediate ozone for manganese removal. Includes 13 references, figures.
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Edition: Vol. - No. Published: 11/01/2002 Number of Pages: 20File Size: 1 file , 400 KB