Chang-Dong Seo

Analysis of UV Filters in Water using Stir Bar Sorptive Extraction (SBSE) and GC/MS-MS

A highly sensitive analytical method based on stir bar sorptive extraction (SBSE) technique and gas chromatography/tandem mass spectrometry (GC/MS-MS) has been developed, allowing the simultaneous multi-analyte determination of seven UV filters in water samples. The stir bar coated with polydimethylsiloxane (PDMS) was added to 40 mL of water sample at pH 3 and stirred at 1,100 rpm for 120 min. Other SBSE parameters (salt effect and presence of organic solvent) were optimised. The method shows good linearity (coefficients > 0.990) and reproducibility (RSD < 12.9%). The extraction efficiencies were above 84% for all the compounds. The limits of detections (LOD) and limits of quantification (LOQ) were 2.1∼8.6 ng/L and 6.8∼27.5 ng/L, respectively. The developed method offers the ability to detect 8 UV filters at ultra-low concentration levels with only 40 mL of sample volume. Matrix effects in tap water, river water, wastewater treatment plant (WWTP) final effluent water and seawater were investigated and it was shown that the method is suitable for the analysis of trace level of 7 UV filters except of benzophenone (BP). The method developed in the present study has the advantage of being rapid, simple, high-sensitive and both user and environmentally friendly.

Analysis of Synthetic Fragrances (SFs) in Water Using Stir Bar Sorptive Extraction (SBSE) and GC-MS/MS

A highly sensitive analytical method based on stir bar sorptive extraction (SBSE) technique and gas chromatography/ tandem mass spectrometry (GC-MS/MS) has been developed, allowing the simultaneous multi-analyte determination of 11 synthetic fragrances (SFs) in water samples. The stir bar coated with polydimethylsiloxane (PDMS) was added to 40 mL of water sample at pH 3 and stirred at 1,100 rpm for 120 min. Other SBSE parameters (salt effect and presence of organic solvent) were optimised. The method shows good linearity (coefficients > 0.990) and reproducibility (RSD < 10.9%). The extraction efficiencies were above 83% for all the compounds. The limits of detections (LOD) and limits of quantification (LOQ) were 2.1~4.1 ng/L and 6.6~12.9 ng/L, respectively. The developed method offers the ability to detect 11 SFs at ultra-low concentration levels with only 40 mL of sample volume. Matrix effects in tap water, river water, wastewater treatment plant (WWTP) final effluent water and seawater were investigated and it was shown that the method is suitable for the analysis of trace level of 11 SFs. The method developed in the present study has the advantage of being rapid, simple, high-sensitive and both user and environmentally friendly.

Monitoring of Hazardous Chemicals for Effluents of STPs and WWTP in the Nakdong River Basin

This study was investigated twenty two hazardous chemicals compounds for effluents of nine sewage treatment plants (STPs) and one waste water treatment plant (WWTP) in the Nakdong Ri-ver Basin. They are eleven phthalates(DMP, DEP, DIBP, DBP, BEEP, DNPP, DHP, DCP, DEHP, DNOP, Dinonyl phthalate, seven aliphatic hydrocarbons(n-Tridecane, n-Tetradecane, n-Pentadecan-e, n-Hexadecane, n-Heptadecane, n-Octadecane, n-Nonadecane, Isoquinoline, 2-Chloropyridine, 2-N-itrophenol, and Benzophenone. The twenty two compounds were analyzed by gas chromatograp-hy mass spectrometry (GC/MS) with liquid-liquid extraction (LLE). Twenteen of twenty two subs-tances were detected. They were DMP, DEP, DIBP, DBP, DEHP, n-Tetradecane, n-Pentadecane, n-Heptadecane, n-Octadecane, n-Nonadecane, Isoquinoline and Benzophenone. Among these, DEHP, DEP and Benzophenone were most frequently observed. They were obtained as ND~36.881 μg/L, ND~0.950 μg/L, ND~2.019 μg/L, respectively. When the substances were calculated the average concentration at 10 points, the maximum average detection concentration was investigated at the Dalseocheon STP.

Biodegradation of UV Filters in Biological Activated Carbon (BAC) Process : Biodegradation Kinetic

In this study, The effects of empty bed contact time (EBCT) and water temperature on the biodegradation of 8 UV filters in biological activated carbon (BAC) process were investigated. Experiments were conducted at two water temperatures (7 and 18°C) and three EBCTs (5, 10 and 15 min). Increasing EBCT and water temperature increased the biodegradation efficiency of UV filters in BAC column. EHMC and BZC were the highest biodegradation efficiency, but BP and 4-MBC were the lowest. The kinetic analysis suggested a first-order reaction model for biodegradation of 8 UV filters at various water temperatures and EBCTs. The first-order biodegradation rate constants (kbio) of 8 UV filters ranging from 0.2730~0.6365 min at 7°C to 0.4824~ 0.8743 min at 18°C. By increasing the water temperature from 7°C to 18°C, the biodegradation rate constants (kbio) were increased 1.5~2.1 times.

Occurrence of Organophosphorus Flame Retardants (OPFRs) in Nakdong River Basin : Mainstreams, Tributaries and STP Effluents

This study was investigated occurrence and distribution patterns of organophosphorus flame retardants (OPFRs) in Nakdong River basin (mainstream, tributaries and sewage treatment plant (STP) effluents). 3 (TCEP, TCPP and TBEP) out of 9 OPFRs were detected in 6 out of 20 sampling sites (mainstream and tributaries), The TCPP and TBEP concentration levels in mainstream samples were ND~114.9 ng/L ng/L and ND~49.1 ng/L, respectively. And the TCEP, TCPP and TBEP concentration levels in tributary samples were ND~1,865.3 ng/L, ND~519.2 ng/L and ND~210.4 ng/L, respectively. 4 (TBP, TCEP, TCPP and TBEP) out of 9 OPFRs were detected in effluents of 11 STPs around the Nakdong River basin. The TBP, TCEP, TCPP and TBEP concentration levels in 11 STP effluents were ND~458.5 ng/L, ND~2,932.7 ng/L, ND~1,320.7 ng/L and ND~655.2 ng/L, respectively. According to the sampling season, change ranges of distribution patterns and detected concentrations of OPFRs were highly variable in the same sampling sites.

Biodegradation of Synthetic Fragrances in Biological Activated Carbon (BAC) Process : Biodegradation Kinetic

Abstract : In this study, The effects of empty bed contact time (EBCT) and water temperature on the biodegradation of 8 synthetic fragrances (SFs) in biological activated carbon (BAC) process were investigated. Experiments were conducted at two water tem-peratures (7 and 18℃) and three EBCTs (5, 10 and 15 min). Increasing EBCT and water temperature increased the biodegradation efficiency of SFs in BAC column. Pentalide and ambrettolide were the highest biodegradation efficiency, but DPMI and ADBI were the lowest. The kinetic analysis suggested a pseudo-first-order reaction model for biodegradation of 8 SFs at various water temperatures and EBCTs. The pseudo-first-order biodegradation rate constants ( k bio ) of 8 SFs ranging from 0.1184~0.6545 min -1 at 7℃ to 0.3087~0.9173 min -1 at 18℃. By increasing the water temperature from 7℃ to 18℃, the biodegradation rate constants ( k bio ) were increased 1.4~2.6 times. Key Words : Synthetic Fragrances (SFs), Biological Activated Carbon (BAC) Process, Water Temperature, Empty Bed Contact Time (EBCT), Biodegradation Kinetic

Synthetic Musk Compounds Removal Using Biological Activated Carbon Process in Drinking Water Treatment

In this study, The effects of three different biological activated carbon (BAC) materials (each coal, coconut and wood based activated carbons) and anthracite, empty bed contact time (EBCT) and water temperature on the removal of MK, HHCB and AHTN in BAC filters were investigated. Experiments were conducted at three water temperatures (5, 15 and 25°C) and four EBCTs (5, 10, 15 and 20 min). The results indicated that coal based BAC retained more attached bacterial biomass on the surface of the activated carbon than the other BAC, increasing EBCT or increasing water temperature increased the synthetic musk compounds (SMCs) removal in BAC columns. The kinetic analysis suggested a first-order reaction model for MK, HHCB and AHTN removal at various water temperatures (5, 15 and 25°C). The pseudo-first-order biodegradation rate constants and half-lives were also calculated for MK, HHCB and AHTN removal at 5, 15 and 25°C. The pseudo-first-order biodegradation rate constants and half-lives of MK, HHCB and AHTN ranging from 0.0082 min to 0.4452 min and from 1.56 min to 84.51 min could be used to assist water utilities in designing and operating BAC filters for SMCs removal.

Occurrence of UV Filters in Nakdong River Basin : Mainstreams, Tributaries and STP Effluents

This study was investigated occurrence and distribution patterns of UV filters in Nakdong River basin (mainstream, tributaries and sewage treatment plant (STP) effluents). 5 (EHS, BP-3, 4-MBC, BZC and EHMC) out of 7 UV filters were detected in 5 out of 20 sampling sites (mainstream and tributaries), 7 UV filters were not detected in mainstream samples, and the EHS, BP-3, 4-MBC, BZC and EHMC concentration levels in tributary samples were ND~60.8 ng/L, ND~72.1 ng/L, ND~57.2 ng/L, ND~60.1 ng/L and ND~85.2 ng/L, respectively. 5 (EHS, BP-3, 4-MBC, BZC and EHMC) out of 7 UV filters were detected in effluents of 11 STPs around the Nakdong River basin. The EHS, BP-3, 4-MBC, BZC and EHMC concentration levels in 11 STP effluents were ND~89.3 ng/L, ND~90.8 ng/L, ND~88.1 ng/L, ND~118.5 ng/L and ND~104.4 ng/L, respectively. According to the sampling season, distribution patterns and detected concentrations of 5 UV filters were similar in June and September 2014, but change ranges of distribution patterns and detected concentrations of 5 UV filters were highly variable in April and November 2014.

Analysis of Trace Levels of Halonitromethanes (HNM) in Water using Headspace-SPME and GC-ECD

Halonitromethanes (HNMs) are one of the most toxic groups of disinfection by-products. Recently, various studies have been fulfilled. An automated headspace-solid phase microextraction (SPME) gas chromatography/electron capture detector (GC-ECD) technique was developed for routine analysis of 9 HNMs in water samples. The optimization of the method is discussed. The limits of detection (LOD) and limits of quantification (LOQ) range from 90 ng/L to 260 ng/L and from 270 ng/L to 840 ng/L for 9 HNMs, respectively. Matrix effects in tap water and sea water were investigated and it was shown that the method is suitable for the analysis of trace levels of HNMs, in a wide range of waters. The method developed in the present study has the advantage of being rapid, simple and sensitive.

Removal Characteristics of Residual Hydrogen Peroxide (H 2 O 2 ) according to Application of Peroxone Process in O 3 /BAC Process

Advanced Oxidation Processes (AOP) have been interested for removing micropollutants in water. Most of water treatment plants (WTPs) located along the lower part of Nakdong River have adopted the O3/BAC process and have interesting in peroxone process a kind of AOP. This study evaluated the removal characteristics of residual hydrogen peroxide (H2O2) combining with the biofiltration process in the next BAC process when the hydrogen peroxide is applied for the WTP operating O3/BAC process. In the experiment, changing the temperature and the concentration of H2O2 of influent, the biofiltration process showed rapidly dropped the biodegradability when the H2O2 concentration was increased and lowered water temperature while BAC process maintained relatively stable efficiency. The influent fixed at 20°C and the concentration of H2O2 at 300 mg/L was continuously input for 78 hours. Most of the H2O2 in the influent did not remove at the biofiltration process controlled 5 to 15 minutes EBCT condition after 24~71 hours operating time while BAC process controlled 5 to 15 minutes EBCT showed 38~91% removal efficiency condition after 78 hours operating time. Besides, after 78 hours continuously input experiment, the biomass and activity of attached bacterial on the biofilter and BAC were 6.0 × 10 CFU/g, 0.54 mg・C/m・hr and 0.4 × 10 CFU/g, 1.42 mg・C/m・hr respectively. These biomass and activity values were decreased 99% and 72% in biofilter and 68% and 53% in BAC compared with initial condition. The biodegradation rate constant (kbio) and half-life (t1/2) in BAC were decreased from 1.173 min to 0.183 min and 0.591 min to 3.787 min respectively according to increasing the H2O2 concentration from 10 mg/L to 300 mg/L at 5°C water temperature and the kbio and t1/2 were 1.510 min to 0.498 min and 0.459 min to 1.392 min at 25°C water temperature. By increasing the water temperature from 5°C to 15°C or 25°C, the kbio were increased 1.1~2.1 times and 1.3~4.4 times. If a water treatment plant operating O3/BAC process is considering the hydrogen peroxide for the peroxone process, post BAC could effectively decrease the residual H2O2, moreover, in case of spilling the H2O2 into the water process line, these spilled H2O2 concentration can be able to decrease by increasing the EBCT at the BAC process.