ORAPIN THAPSINGKAEW1, WERAWAN
AND VILILUCK KIJJANAPANICH2
1Division of Toxicology, Department of Forensic Medicine,
Faculty of Medicine, 2Department of Environmental Engineering, Faculty of Engineering,
Chiang Mai University, Thailand.
E-mail : email@example.com
Chlorine is a normal disinfectant
used in conventional water treatment, which can react with natural organic matter
in raw water to form trihalomethanes (THMs). The THMs consist of chloroform,
dichlorobromomethane, dibromochloromethane and bromoform. They are classified
as carcinogenic substances. The US.EPA promulgates the maximum contaminant level
(MCL) of THMs at 80 mg/L in drinking water. Using ozone to replace chlorine
in order to mitigate the THMs by-product formation was our goal for this study.
The level of THMs in water samples treated conventionally was measured from
raw, pre-, intermediate- and post-chlorination water samples from Mae-Kuang
water treatment plant in Chiang Mai. An ozonation pilot plant, from which pre
and post treated water samples were taken, was operated at an oxidation-reduction
potential (ORP) of 500, 600 and 700 mV. THMs were analyzed by gas chromatography
with an electron capture detector. The results showed that THMs in raw water
were not detected, whereas, the average value of THMs in water samples from
ozonation was lower than that of the THMs in the chlorination process. There
was no correlation of ORP variation in the reduction of the THMs formation.
In conclusion, using ozone could reduce the formation of THMs. The concentration
of THMs in water samples from chlorination and ozonation processes is slightly
lower than the MCL.
ที่มา ABSTRACT นำเสนอที่ การประชุมวิชาการสมาคมพิษวิทยาแห่งประเทศไทย ประจำปี 2547 อาหารกับความปลอดภัย วันศุกร์ที่ 17 ธันวาคม 2547 โรงแรมมิราเคิลแกรนด์ กรุงเทพฯ