Modeling chlorine residual and disinfection byproduct formation in circulating distribution systems

• Main Author: Moore, Brigham
• Format: Thesis
• Language: English
• Published: University of Alaska Anchorage 2014
• Subjects: Civil engineering|Environmental engineering; Arctic
• Online Access: http://pqdtopen.proquest.com/#viewpdf?dispub=1555603

Disinfection by-products (DBPs) form as Natural Organic Matter reacts with disinfectants used in water treatment. Several of the DBPs formed are known carcinogens and regulated by the EPA for drinking water. Arctic utility design requires piped systems to recirculate water to avoid excessive heat loss and subsequent freezing. Recirculating systems have the potential to retain water in the system for extended periods of time and in turn allow longer reaction times for chlorine decay and the formation of DBPs. The purpose of this study was to appropriately model the effect of chlorine decay and DBP formation for these unique cold regions' distribution systems based on water age and total organic carbon concentration. The model resulted in the average retention time being double for a continuously circulating system than for a standard system of equal size. The extended retention time correlated to lower chlorine residuals and a DBP formation up to 2.5 times the regulatory limit.