Study of the formation of trihalomethanes in Baghdad water supply system
Abstract
Study of the formation of trihalomethanes in Baghdad water supply system
Incoming article date: 14.07.2013Chlorination is the most common, and in fact no alternative method of disinfection using in Baghdad water supply system. Thus there is an urgent need to control the trihalomethanes (THMs) in drinking water. One of the objectives of this study is to investigate the content of THMs in Baghdad water supply network. Studies showed that the substantial amount of THMs formed in water distribution system, THMs content tends to increase with the distance from the starting point coupled with a decrease of residual chlorine concentration. It is observed that in summer total THMs concentration growth rate in water supply network was 1.3-1.4 times higher than in winter as well as total amount of THMs increase by 30 percent in summer. It was found that the concentration of total THMs never exceeded 80 μg/l – the level specified in National Primary Drinking Water Regulations: Disinfectants and Disinfection Byproducts (Stage 1) established by USEPA. However, in summer total THMs concentration in the water always exceeded 40 μg/l – the level set in accordance with Stage 2 of this Rule. The most of total THMs (73-80%) were bromine compounds (CHCl2Br, CHClBr2 and CHBr3). It is shown that the most efficient way to reduce THMs in Baghdad water supply network is to use the chlorine dioxide for chlorination.
Keywords: chlorine dioxide, chlorination, drinking water, trihalomethanes (THM), water supply network, water supply system