TITLE:
Small Water Distribution System Operations and Disinfection By Product Fate
AUTHORS:
Sandhya Rao Poleneni, Enos C. Inniss
KEYWORDS:
Trihalomethanes; Pipe Loop; Chlorination; Distribution Systems; Formation Kinetics
JOURNAL NAME:
Journal of Water Resource and Protection,
Vol.5 No.8A,
August
9,
2013
ABSTRACT: The Stage-2 Disinfectant and Disinfection By-Product (D/DBP)
regulations force water utilities to be more concerned with their finished and
distributed water quality. Compliance requires changes to their current
operational strategy, which affect the formation of DBPs over time. This study
quantifies changes in DBP formation and chlorine decay kinetics under different
operational conditions and pipe materials found at many small-scale water
utilities. A physical model (Pipe Loop) of a distribution system was used to
evaluate the change in water quality from conditions such as having a high
chlorine dosage entering the distribution system, using a chlorine booster
system in the distribution system, and operation of clearwells/storage tanks.
The High Chlorine Run (HC) is least favorable option with approximately 64% and
30% higher TTHMs than Normal Run (NR) and Chlorine Booster Run (CB),
respectively. High Chlorine conditions also minimize the wall effects. The
location of Boosters should always be after the storage systems to avoid extra
contact time that can produce approximately 23% - 78%
higher TTHMs. The following trends are discovered from the data analysis:
Chlorine residual HC > CB > NR and TTHM NR > CB > HC.