• Korean Journal of Environmental Biology
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• v.19 no.1
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• pp.59-69
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• 2001

Among the biodegradability tests, TOC-HANDAI and OECD method were utilized to examine the degree of biodegradation of endocrine disruptors, Bisphenol A (BPA) and Nonylphenol. Both methods used natural water microcosms and measured their biodegrada-bilities of BPA and Nonylphenol, in terms of TOC or DOC degradation with time for 28 days. Biodegradabilities for BPA, 73-78% with TOC-HANDAI method and 77-81% with OECD method were obtained respectively at the end of experiment. There was no difference in BPA degradation between two methods. BPA degradation was described by two distinct first order decay rates (k$_1$ and k$_2$) which could be separated by a simple visual fitting. Most of the initial decay reaction accelerated within 1-7 days with k$_1$of 0.24-0.34 $day^{-1}$. And the following another long term first order decay coefficient (k$_2$) showed 0.02-0.05 day$^{-1}$ with much flat slope. About 20-25% of initial BPA remained at the end of experiment. It suggests that the remaining TOC components in BPA biodegradation considered to be refractory metabolites of BPA. Nonylphenol at each sampling point was appeared to be mineralized 20-48% of initial TOC concentration. Consequently Nonylphenol seems more recalcitrant against biodegradation. BPA was not detected in the detection limit of ppb in the watershed of Daechung reservoir and Kum river. However 25 ppb concentration of BPA was detected at the influent of industrial wastewater treatment plant in Taejon.

• Environmental Engineering Research
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• v.11 no.4
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• pp.181-193
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• 2006

The hydrophilic or hydrophobic characteristics of dissolved organic matter (DOM) from different origins in lake and river waters were investigated using spectrometric and chromatographic analyses of water samples. DOM in a deep, mesotrophic lake (Lake Unmun) was fractionated using three types of ion exchange resins and classified into aquatic humic substances (AHS), hydrophobic neutrals (HoN), hydrophilic acids (HiA), hydrophilic neutrals (HiN), and bases (BaS). The DOM fractionation provided insight into the understanding of the nature of heterogeneous DOM molecules present in different water sources. The UV/DOC ratios were determined for samples from the influent river and lake waters during DOM fractionation and incubation. AHS prevailed over DOM in the lake and river waters. After biodegradation, the relative contribution of AHS in the total DOM became more significant. It indicates that the AHS fraction would increase while water stay long time in the lake.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.1
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• pp.13-25
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• 2007

The water treatment plants in Seoul Metropolitan Area, which are under Korea Water Resources Corporation(KOWACO)'s management, take water from Paldang Reservoir in Han River System for drinking water supply. There are taste and odor (T&O) problems in the finished water because the conventional treatment processes do not effectively remove the T&O compounds. As part of countermeasures for taste and odor control, KOWACO is planning to introduce advanced water treatment process such as ozone and GAC in near future. This study evaluated the removal characteristics of T&O and dissolved organic matter (DOM) to find design and operation parameters of advanced water treatment processes in a pilot-scale treatment plant. The GAC adsorption capacity for DOC in the two GAC system (GAC and $O_3$-GAC) at an EBCT of 14min was mostly exhausted after 9months. The differency of the removal efficiency of DOC between $O_3$-GAC and GAC increased with increasing operation time because the bioactivity in $O_3$-GAC process was enhanced by post-ozone process. Removal by conventional treatment was unable to reach the target TON(threshold odor number) of 3 but GAC systems at an EBCT(empty bed contact time) of 14 min were able to archive the target with few exception. During the high T&O episodes, PAC as a pretreatment together with GAC could be useful option for T&O control. However, substantial TON removal continued for more than two year (> 90,000 bed volumes). At the spiking of less concentration 26 to 61 ng/L in the influent of GAC systems, GAC absorber and $O_3$-GAC processes could meet the treatment target. The better spike control after 12 and 19 months of operation compared to that after 7 months of operation is a strong indication of biological control. The results presented in this study had shown that $O_3$-GAC process was found to be more effective for T&O control than GAC process. And the main removal mechanism in GAC systems were adsorption capacity and biodegradation.