AWWA ACE68625

This powerpoint presentation begins by providing a brief overview of the Mystic Water System. The problem statement includes the following:compliance with Stage 2 Disinfectant/Disinfection Byproduct (D/DBP) Rule; and,control of Mn and Fe.The study objectives include the following:evaluate impacts of pre-filter chlorine on DBP levels; and, investigate options to decrease DBP formation whilemaintaining Fe and Mn removal.The Scope of Work includes the following:full-scale studies of sampling across plants at various prefilterCl₂ doses, DBP and metals analyses, collecting filtermedia cores; and,bench-scale studies of chlorine demand, kinetics, DBPformation, chloramination, jar and column experiments. Presentation conclusions indicate that: pre-filter Cl₂ and KMnO₄ rapidly oxidized iron andmanganese (with pH controlled at 7.0-7.2);a low pre-filter chlorine dose (2 mg/L) produces similarfilter influent water quality conditions as that of a high prefilterchlorine dose (6-8 mg/L); plant effluent DBP formation directly proportional to prefilterchlorine dose;decreasing the pre-filter chlorine from 8 mg/L to 2 mg/Lresulted in 70-90% decrease in plant effluent DBPformation and short term control of Mn and Fe;after 35-55 days low pre-filter chlorine (2.0 mg/L) resultedin an apparent release of Mn; and,increasing pre-filter chlorine to 4-5 mg/L prevents Mnrelease, but increases DBP formation. Includes figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2008

Number of Pages:

30

File Size:

1 file , 950 KB