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DOI : ,    Vol.9, No.4, 45 ~ 55, 2001
Title
A Study on the Characteristics of Humic Substance Isolated from the Daecheung Lake Sediment
김미숙Mi Suk Kim,김철규Cheol Gyu Kim
Abstract
Natural organic matter such as humic substance (HS) in surface water causes a lot of problems such as colour, taste, odour and lower efficiency in water treatment process. In addition to these, in the chlorination process, HS reacts with chlorine and produces disinfection-by-products (DBPs), e.g., trihalomethanes (THMs), and trihaloacitate acids (HAAs). The maximum concentrations of these D/DBYs have been recommended by the World Health Organisation (WHO) and these parameters have been regulated in the D/DBPs Rule by the USEPA and other developed countries environmental agencies. This study aims to characterize the HS isolated from the sediment of Daecheung Lake, Korea by using apparent. molecular weight distributions(AMWD) and by using water quality terms such as TOC, DOC, UV_(254), THMFP, SUVA, STHMFP. HS used in this study was isolated from the sediment of Lake Daecheung in Daejeon of Korea using an established procedure. The isolated HS was then separated into two fractions, i.e., humic and fulvic acids by using solubility difference. The AMWD of HS was determined by an ultrafiltration procedure. The physico-chemical parameters of humic and fulvic acids (e.g., UV_(254)-abs, DOC, SUVA and THMFP) were measured following the AWWA standard procedures. The results of characteristics of HS isolated from sediment are obtained as follows : it was composed of humic acid of 2.12㎎ TOC and 3.63㎎ TOC/g HS, humic acid of 35.7% and fulvic acid of 64.3% in term of DOC, while humic acid of 69.3% and fulvic acid of 30.7% in term of UV_(254). By the dilution of HS extracts with distilled and deionized water, The values of DOC, UV absorbance and turbidity were proportionated to each other, but THMFP values were not proportionated. In a percentage of DOC, humic acid in 4.61㎎/ℓ of DOC had an AMWD of 64.2% of >30K dalton, 11.6% of 30∼10k dalton, 3% of 10∼3k dalton, 21% of <3k dalton. Fulvic acid in 4.61㎎/ℓ of DOC had an AMWD of 22.6% of >30k dalton, 43.2% of 30∼10k dalton, 3% of 10∼3k dalton, 31% of <3k dalton. In addition, SUVA and STHMFP values of humic acid was higher than those of fulvic acid in general. From the consideration of SUVA and STHMFP, it seems that humic acid will be of a higher potential of trihalomethane formation than fulvic acid, when it was induced into disinfection process of chlorination.
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