AWWA WQTC65875

This powerpoint presentation begins by providing background information on the City of Cheyenne, Wyoming's sources of raw water supply and an extreme manganese event that occurred in 2006. Causes of the manganese event are presented, along with existing plant processes utilized for treating manganese during the event, and effective oxidation at right location was key to oxidize manganese for removal. Conclusions for manganese management included: source of manganese release is Crystal Lake sediments; long term solution must control manganese release in Crystal Lake; release of manganese from pipelines contributes to event; best manganese removal occurs when oxidation completed before settling; and, plant design inadequate for removing high levels of manganese. An alternatives matrix is presented, along with major recommendations for action that include: aerate at depth in Crystal Lake; and, feed potassium permanganate to raw water transmission pipelines to oxidize Mn/Fe. Includes table, figures.