Investigation of Trihalomethanes Contamination in Surface Water Treatment Plants and Water Supply Network in An Giang-Mekong Delta Province of Viet Nam

The contaminated water causes many waterborne diseases such as cholera, typhoid, etc. followed by many serious public health crises mostly in developing countries due to the low hygiene conditions. Trihalomethanes (THMs) are formed by the reactions between natural organic matter (NOM) and chlorine in the disinfection. The organic contamination and THMs formation were investigated in three study areas such as two surface water treatment plants (WTPs) (i.e., raw water, each unit treatment process) located in Long Xuyen (LX WTP) and Binh Duc (BD WTP) and the water supply network in Long Xuyen city. The achieved data of those two WTPs were used to compare with Tan Hiep WTP (TH WTP) in Ho Chi Minh City. Dissolved organic carbon of 2.9-3.2 mg/L was obtained in analyst of raw water and specific ultraviolet absorbance of water samples was below 1 L/ mg·m. All samples were collected in water supply network presenting THMs concentration meet the requirement of Vietnamese drinking water regulation. High chlorine concentration of 96-116 µg/L in raw water of two WTPs combining with available organic matters could cause high potentiality of THMs formation. Total THMs concentration of 36-116 µg/L was measured in raw water samples of two WTPs as study areas. The ability of trihalomethane formation potential (THMFP) undertaken at WTPs displayed from 1,198 µg/L to 2,837 µg/L.