AWWA WQTC58901

For many utilities the aesthetic problems that accompany elevated manganese levels are ofparamount concern. Unsightly deposits and colored water problems cause innumerablecomplaints in some systems. Such conditions can occur even when manganese levels are belowthe 0.05 mg/L secondary standard, causing some utilities to set internal goals of 0.015 or 0.02mg/L. Results from two projects are presented in this paper.In recent years, the Hyde Park Water Treatment Plant has received customer complaintsdescribed as "dirty water" or "pinkish water". In addition, dark brown or black deposits haveformed on some of the plant equipment and the walls of the clearwell and a dark sediment/filmwas observed in a storage tank. These complaints and deposits were determined to be caused bymanganese passing through the treatment plant after process changes were implemented to reducedisinfection byproduct levels.Upgrades to the Stamford Water Treatment are currently being designed. The raw water supplyis a reservoir that undergoes stratification. During the late summer period, elevated manganeselevels caused by anoxic conditions in the bottom waters and taste and odor episodes caused bygeosmin and MIB are the major treatment concerns. Manganese is controlled by the induced-greensandeffect that occurs when chlorine is added prior to anthracite or sand filters. Conversionto GAC filters to control the taste and odor events may inhibit the induced-greensand effect.Manganese control, although not a health issue, is essential for maintaining consumer confidence.The results of this paper will help utilities that experience difficulty in controlling manganese, and also those utilities that are considering treatment changes to reduce DBPs or control taste and odors todo so in a manner that will not compromise manganese removal. Includes tables.

Product Details

Edition:

Vol. - No.

Published:

11/02/2003

Number of Pages:

10

File Size:

1 file , 370 KB