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ABSTRACT: The Cheng-Ching Lake Water Treatment Plant (CCLWTP) is the main supplier of domestic water for the Greater Kaohsiung area, the second largest metropolis in Taiwan. Biological activated carbon (BAC) filtration is one of the major treatment processes in CCLWTP. The objectives of this study were to evaluate the effectiveness of BAC filtration on water treatment in the studied advanced water treatment plant and its capability on pollutants [e.g., AOC (assimilable organic carbon), bromide, bromate, iron] removal. In this study, water samples from each treatment process of CCLWTP were collected and analyzed periodically to assess the variations in concentrations of AOC and other water quality indicators after each treatment unit. Moreover, the efficiency of biofiltration process using granular activated carbon (GAC) and anthracite as the fillers was also evaluated through a column experiment. Results show that the removal efficiencies for AOC, bromide, bromate, and iron are 86% 100%, 17%, and 30% after the BAC filter bed, respectively. This indicates that BAC filtration plays an important role in pollutant removal. Results also show that AOC concentrations in raw water and effluent of the CCLWTP are approximately 143 and 16 microg acetate-Cl(-1), respectively. This reveals that the treatment processes applied in CCLWTP is able to remove AOC effectively. Results of column study show that the AOC removal efficiencies in the GAC and anthracite columns are 60% and 17%, respectively. Microbial colonization on GAC and anthracite were detected via the observation of scanning electron microscopic images. The observed microorganisms included bacteria (rods, cocci, and filamentous bacteria), fungi, and protozoa. Results from this study provide us insight into the mechanisms of AOC removal by advanced water treatment processes. These findings would be helpful in designing a modified water treatment system for AOC removal and water quality improvement.
Chemosphere 05/2008; 71(9):1786-93. · 3.21 Impact Factor
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ABSTRACT: Recently, the appearance of assimilable organic carbon (AOC) in the water treatment system and effluent of the treatment plant has brought more attention to the environmental engineers. In this study, AOC removal efficiency at the Cheng-Ching Lake water treatment plant (CCLWTP) was evaluated. The main objectives of this study were to: (1) evaluate the treatability of AOC by the advanced treatment system at the CCLWTP, (2) assess the relativity of AOC and the variations of other water quality indicators, (3) evaluate the effects of sodium thiosulfate on AOC analysis, and (4) evaluate the efficiency of biofiltration process using granular activated carbon (GAC) and anthracite as the fillers. Results show that the averaged influent and final effluent AOC concentrations at the CCLWTP were approximately 124 and 30 µg acetate-C/L, respectively. Thus, the treatment plant had an AOC removal efficiency of about 76%, and the AOC concentrations in the final effluent met the criteria established by the CCLWTP (50 µg acetate-C/L). Results indicate that the biofiltration process might contribute to the removal of the trace AOC in the GAC filtration process. Moreover, the removal of AOC had a correlation with the decrease in concentrations of other drinking water indicators. Results from a column test show that GAC was a more appropriate material than anthracite for the AOC removal. Results from this study provide us insight into the mechanisms of AOC removal by advanced water treatment processes. These findings would be helpful in designing a modified water treatment system for AOC removal and water quality improvement.
Desalination. 01/2006; 202:318-325.
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ABSTRACT: Methyl tert-butyl ether (MTBE) has been used as a gasoline additive to improve the combustion efficiency and to replace lead since 1978. Because it is widely used and it has been disposed inappropriately, MTBE has become a prevalent groundwater contaminant worldwide. In this study, two petroleum-hydrocarbon contaminated sites (Sites A and B) were selected to evaluate the occurrence and effectiveness of natural attenuation of MTBE at these two sites. Field investigation results indicate that the natural attenuation mechanisms of MTBE at both sites were occurring with the first-order attenuation rates of 0.0021 and 0.0048 1day(-1) at Sites A and B, respectively. Results also reveal that the intrinsic biodegradation pattern was the most important mechanism among the natural attenuation processes at both sites. Results from BIOSCREEN simulation suggest that biodegradation was responsible for 78 and 59% of MTBE mass reduction at Sites A and B, respectively. Investigation results show that MTBE plume at Site B could be effectively controlled via natural attenuation processes. However, MTBE plume at Site A has migrated to a farther downgradient area and passed the boundary line of the site. Thus, more active groundwater remedial technologies should be applied at Site A to protect the downgradient environment. Results from this study suggest that natural attenuation might be feasible to be used as a remedial option for the remediation of MTBE-contaminated site on the premise that (1) detailed site characterization has been conducted and (2) the occurrence and effectiveness of natural attenuation processes have been confirmed.
Journal of Hazardous Materials 11/2005; 125(1-3):10-6. · 4.17 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: Recently, the appearance of assimilable organic carbon (AOC) in the water treatment system and effluent of the treatment plant has brought more attention to the environmental engineers. In this study, AOC removal efficiency at the Cheng-Ching Lake water treatment plant (CCLWTP) was evaluated. The main objectives of this study were to: (1) evaluate the treatability of AOC by the advanced treatment system at the CCLWTP, (2) assess the relativity of AOC and the variations of other water quality indicators, (3) evaluate the effects of sodium thiosulfate on AOC analysis, and (4) evaluate the efficiency of biofiltration process using granular activated carbon (GAC) and anthracite as the fillers. Results show that the averaged influent and final effluent AOC concentrations at the CCLWTP were approximately 124 and 30 μg acetate-C/L, respectively. Thus, the treatment plant had an AOC removal efficiency of about 76%, and the AOC concentrations in the final effluent met the criteria established by the CCLWTP (50 μg acetate-C/L). Results indicate that the biofiltration process might contribute to the removal of the trace AOC in the GAC filtration process. Moreover, the removal of AOC had a correlation with the decrease in concentrations of other drinking water indicators. Results from a column test show that GAC was a more appropriate material than anthracite for the AOC removal. Results from this study provide us insight into the mechanisms of AOC removal by advanced water treatment processes. These findings would be helpful in designing a modified water treatment system for AOC removal and water quality improvement.
Desalination.
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[show abstract]
[hide abstract]
ABSTRACT: Methyl tert-butyl ether (MTBE) has been used as a gasoline additive to improve the combustion efficiency and to replace lead since 1978. Because it is widely used and it has been disposed inappropriately, MTBE has become a prevalent groundwater contaminant worldwide. In this study, two petroleum-hydrocarbon contaminated sites (Sites A and B) were selected to evaluate the occurrence and effectiveness of natural attenuation of MTBE at these two sites. Field investigation results indicate that the natural attenuation mechanisms of MTBE at both sites were occurring with the first-order attenuation rates of 0.0021 and 0.0048 1 day−1 at Sites A and B, respectively. Results also reveal that the intrinsic biodegradation pattern was the most important mechanism among the natural attenuation processes at both sites. Results from BIOSCREEN simulation suggest that biodegradation was responsible for 78 and 59% of MTBE mass reduction at Sites A and B, respectively. Investigation results show that MTBE plume at Site B could be effectively controlled via natural attenuation processes. However, MTBE plume at Site A has migrated to a farther downgradient area and passed the boundary line of the site. Thus, more active groundwater remedial technologies should be applied at Site A to protect the downgradient environment. Results from this study suggest that natural attenuation might be feasible to be used as a remedial option for the remediation of MTBE-contaminated site on the premise that (1) detailed site characterization has been conducted and (2) the occurrence and effectiveness of natural attenuation processes have been confirmed.
Journal of Hazardous Materials.
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[show abstract]
[hide abstract]
ABSTRACT: The Cheng-Ching Lake Water Treatment Plant (CCLWTP) is the main supplier of domestic water for the Greater Kaohsiung area, the second largest metropolis in Taiwan. Biological activated carbon (BAC) filtration is one of the major treatment processes in CCLWTP. The objectives of this study were to evaluate the effectiveness of BAC filtration on water treatment in the studied advanced water treatment plant and its capability on pollutants [e.g., AOC (assimilable organic carbon), bromide, bromate, iron] removal. In this study, water samples from each treatment process of CCLWTP were collected and analyzed periodically to assess the variations in concentrations of AOC and other water quality indicators after each treatment unit. Moreover, the efficiency of biofiltration process using granular activated carbon (GAC) and anthracite as the fillers was also evaluated through a column experiment. Results show that the removal efficiencies for AOC, bromide, bromate, and iron are 86% 100%, 17%, and 30% after the BAC filter bed, respectively. This indicates that BAC filtration plays an important role in pollutant removal. Results also show that AOC concentrations in raw water and effluent of the CCLWTP are approximately 143 and 16 μg acetate-C l−1, respectively. This reveals that the treatment processes applied in CCLWTP is able to remove AOC effectively. Results of column study show that the AOC removal efficiencies in the GAC and anthracite columns are 60% and 17%, respectively. Microbial colonization on GAC and anthracite were detected via the observation of scanning electron microscopic images. The observed microorganisms included bacteria (rods, cocci, and filamentous bacteria), fungi, and protozoa. Results from this study provide us insight into the mechanisms of AOC removal by advanced water treatment processes. These findings would be helpful in designing a modified water treatment system for AOC removal and water quality improvement.
Chemosphere.
