Document Type

Thesis - Open Access

Award Date

2015

Degree Name

Master of Science (MS)

Department / School

Civil and Environmental Engineering

First Advisor

Guanghui Hua

Keywords

Disinfection byproducts, DBPs, water contamination, dehalogenation, water disinfection

Abstract

Water scarcity is one of the most challenging issues in the world in the 21st century. It is estimated that there are more than one billion of people without adequate access to freshwater and facing water shortages and water deficits. People are forced to drink polluted water despite the risk of consuming pathogenic microorganisms in the water that transmit waterborne diseases such as bacterial infections, protozoal infections and viral infections. The water disinfection process is one of the most important environmental technological advances in the 20th century which inactivates microbial contaminants in drinking water. Disinfection byproducts (DBPs) are a group of chemical compounds formed from the reaction between natural organic matter and chemical disinfectants. The formation of DBPs in drinking water has caused serious health concerns since the discovery of trihalomethanes in chlorinated drinking waters in the 1970s. Many studies have evaluated factors affecting the formation of DBPs within water treatment plants. Relatively less is known about the fate of DBPs in the distribution system. The objective of this study was to evaluate the impacts of pH and temperature on the degradation of total organic chlorine (TOC1), bromine (TOBr) and iodine (TOI). In this study, we produced TOC1 (Cl2), TOBr, TOI, and TOC1 (NC2Cl) from reactions between Suwannee River fulvic acid and chlorine, bromine, iodine and chloramine, respectively. The impact of different pH values (7.0, 8.3 and 9.5) and temperatures (10°C, 20°C, 30°C, and 55°C) on the degradation of these DBPs was investigated after oxidant residuals were exhausted. The results show that halogenated DBPs degrade through based-catalyzed dehalogenation processes. The degradation of TOC1, TOBr, and TOI increased with increasing pH values. Increasing temperatures also increased the degradation kinetics of these DBPs. Iodinated DBPs were less stable than brominated DBPs, which again were less stable than chlorinated DBPs. Relatively high degradation kinetics were also found for chloraminated DBPS. In general, the relative stability of different DBPs are in the order of TOC! (Cl2)>TOBr>TOI≈TOC1 (NH2CL).

Library of Congress Subject Headings

Water -- Purification -- Disinfection -- By-products
Hydrogen-ion concentration
Temperature
Water quality

Description

Includes bibliographical references (pages 59-65)

Format

application/pdf

Number of Pages

77

Publisher

South Dakota State University

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Rights Statement

In Copyright