AWWA MTC64547

This slide presentation outlines a comparison of two state-of-the-art water treatment plants (WTPs) designed eight years apart. The issues include: both towns have high levels of Fe and Mn; staining with red or black material; taste - metallic or vinyl; appearance - color, oily appearance, crusty sheen to water's surface; may grow bacteria; and, may cause slimes and clogging of water systems. Pilot studies were done on the Littleton WTP from November 1993 to January 1994 and from February to March 1995, and on the Franklin WTP from June to July 2002. The primary goal was to reduce Iron and Manganese: Iron (Fe) < 0.3 mg/l, and Manganese (Mn) < 0.05 mg/. The Littleton Pilot Study involved testing three technologies that included: ozone oxidation followed by membrane filtration; manganese greensand adsorption; and, oxide coated sand filtration. All three alternatives reduced iron and manganese to very low levels - < 0.05 mg/l. Only ozone/ultrafiltration met the secondary goals that included: meeting possible future regulations; minimizing quantities of residuals; and, ease of operation as plant is un-manned part of day. The Franklin Pilot Study only examined oxidation followed by membranes. Two membrane manufacturers participated in the pilot trials that involved ozone followed by membranes and potassium permanganate followed by membranes. Both iron and manganese were reduced to <0.05 mg/l. Franklin selected ozone followed by membranes for its treatment method. Includes tables, figures.