AWWA ACE68626

This powerpoint presentation begins by providing a brief overview of the chloramination issue of nitrification, factors affecting nitrification, trihalomethane (THM) cometabolism, and chloroform cometabolism. Research goals included: examiningthe role THMs play in preventingnitrification; and,improving the ability to predict nitrification episodesbased, in part, on background THMconcentrations. The experimental approach included the following:four annular reactors simulate distributionsystem -- inner cylinder rotates to createhydraulic shearing force;parameters wereLake Austin (tap) water culture andtypical drinking water conditions;pH 7-9;Ammonia -- 0.5 to 1 mg/L NH₃-N;Chlorine -- 1 to 3 mg/L as Cl₂; varied THM concentrations and bromineincorporation ratio; set up two identical reactors with the onlydifference being the presence of THMs;monitor effluent ammonia, nitrite, andmonochloramine concentrations;nitrification indicated bypresence of nitrite (NO₂^-), decrease in ammonia concentration, andloss of monochloramine residual; and,compare nitrification onset between controlreactors and THM reactors. Presentation conclusions indicate that:THMs have a measurable effect onnitrification at drinking water conditions, and THMs slowed onset of nitrification;nitrification occurs in the presence of THMsunder drinking water conditions;trends generally agreed with Nitrification Index (NI) model; and,predictive power would likely improve ifdisinfection kinetics were better understood. Includes figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2008

Number of Pages:

28

File Size:

1 file , 800 KB