AWWA WQTC69367

This powerpoint presentation begins by providing a brief overview of nitification as a health threat. The objectives of the study were to:evaluate nitrification control by continuouslyfeeding sodium chlorite to an isolated area ofthe Glendale, California, distribution system;determine the associated cost of that treatment; and,gather information for system-wide applicationof chlorite ion control of nitrification. The Glendale Demonstration ProjectStudy Phases included the following: Phase I - Aug 1, 2006 to Feb 12, 2007, chlorite added to all three reservoirs;Phase II - Feb 13, 2007 to Aug 15, 2007, no chlorite added, breakpoint chlorination; and,Phase III - Aug 16, 2007 to October 31,2007, chlorite added to all three reservoirs. Study location and chemical feed system are presented, along with results of all three phases. Differences between Phase Iand Phase III included the following:in Phase I, reservoirs 1290 and 1666 werefully nitrified when the chlorite feed began;in Phase III, the same reservoirs had beensubjected to breakpoint chlorination killingall of the ammonia oxidizing bacteria (AOB) before starting the chloritefeed; thus, successful control of nitrification withchlorite is dependent on starting with asystem generally free of AOB. Possible AOB protective mechanisms are presented, along with study summary and conclusions that indicate the following: traditional methods of nitrification control haveachieved inconsistent results in distribution systems;bench, pilot, demonstration, and full-scale studiesacross the U.S. have shown that chlorite ion can beeffective for nitrification prevention; and,the results from the Glendale demonstration studyproved that chlorite effectively controllednitrification in reservoirs and the distributionsystem when it was used in a system thatwas not already undergoing severenitrification. Includes 8 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2008

Number of Pages:

39

File Size:

1 file , 1.4 MB