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Objectives : In the case of pharmaceuticals with high possibility of inflow into the large drinking water treatment plant (DWTP) located in the downstream of the Nakdong River, we tried to evaluate the removal efficiency of pharmaceuticals in the both ozone (O3) and the UV/H2O2 treatment as an alternative of post-O3 process. It was intended to be used as data for the advanced WTP project by prediction of the removal efficiency in the O3 and UV/H2O2 processes with varying water quality conditions.Methods : O3 and UV/H2O2 process were performed for 19 kinds of pharmaceuticals in the sand-filtered water of DWTP. In order to evaluate the removal efficiency in deionized water (DI) and sand-filtered water (SFW) matrices, 19 pharmaceuticals were spiked at a concentration of 100 ng/L, respectively. In the O3 process, the specific O3 dose was 0.1∼2.0 gO3/gDOC (0.25∼5.0 mgO3/L). In the UV/H2O2 process, H2O2 (5 and 10 mg/L) was added to the sample before UV was irradiated (0∼1,500 mJ/cm2).Results and Discussion : In the case of simulated post-O3 process, the removal efficiency of high-ozone reactive pharmaceuticals (kO3 6.5×102∼2.6×106 M-1 s-1) was up to 92% at the specific O3 dose of 0.2 gO3/gDOC. However, the removal efficiency of iopromide (IPM) and primidone (PRM) was only 36∼45% in the same O3 dose (0.2 gO3/gDOC) due to the low O3 reactivity (kO3 < 1 M-1 s-1). A specific O3 dose of 2.0 gO3/gDOC (=5 mgO3/L) was required to achieve a removal efficiency of over 90% for IPM and PRM, indicating that these O3-refractory pharmaceuticals are difficult to control by O3 process. In the case of simulated UV/H2O2 (10 mg/L H2O2) process, the removal efficiency of 19 pharmaceuticals at the UV fluence of 500 and 1,000 mJ/cm2 were 63∼99% and 87∼99%, respectively, and caffeine (CFN) had the lowest removal efficiency. For the O3-refractory pharmaceuticals (i.e., IPM and PRM), the removal efficiency was higher in the UV/H2O2 process than that in the O3 process due to the high reactivity with OH radical (kOH = 3.3×109 and 5.2×109 M-1 s-1). Prediction of removal efficiency for pharmaceuticals in the O3 and UV/H2O2 process was performed using chemical kinetics model to evaluate the change in removal efficiency with varying DOM concentration. As a result of prediction model for O3, when the DOM concentration increased from 1.5 to 3.0 mg/L, the removal efficiency of IPM and PRM decreased by 22∼24% and 15∼24%, respectively. In the case of UV/H2O2 process (10 mg/L H2O2 and UV fluence of 500~1,000 mJ/cm2), the removal efficiency of 16 kinds of pharmaceuticals was reduced by 0∼29%, and the degree of reduction in the removal efficiency of CFN was the highest.Conclusions : As a result of evaluation and prediction of the removal efficiency of pharmaceuticals in the O3 and UV/H2O2 treatment processes, it is confirmed that the possibility of applying the UV/H2O2 treatment as an alternative process to the O3 to abatement of pharmaceuticals.

Objectives:In this study, we used liquid chromatograph-organic carbon detector-organic nitrogen detector (LC-OCD-OND) to evaluate adsorption and breakthrough characteristics of NOM fractions (biopolymers (BP), humic substances (HS), building blocks (BB) and low molecular weight organic substances (LMW-O)) according to the various characteristics of the different materials of granular activated carbons (GACs).Methods:Breakthrough characteristics, adsorption capacity and partition coefficients were evaluated by NOM fractions (BP, HS, BB, and LMW-O) using a lab-scale GAC adsorption column filled with coal-, coconut- and wood-based GAC. The GAC column test was operated with 10 minutes empty bed contact time (EBCT). The pore characteristics of each GAC were evaluated using an automated gas sorption analyzer (Autosorb iQ3, Quantachrome, USA) and the concentrations of NOM fractions in the influent and effluent were analyzed using chromatography LC-OCD-OND (Model 8, DOC-Labor, Germany).Results and Discussion:NOM adsorption capacity was evaluated for different materials of laboratory scale GAC adsorption column test. To study the adsorption behavior of individual NOM fractions according to the operation time, NOM was fractionated into BP, HS, BB and LMW-O by LC-OCD-OND, and the individual NOM fractions were quantified. Higher MW like BP was not adsorbed to GAC, in contrast, HS, BB, and LMW-O were well removed during the initial operation period, the concentrations in the effluent gradually increased as increase the operation period until reaching to the pseudo steady-state. Poor removal of BP in GAC adsorption may be a result of blocking the pores with large MW BP and hinder the access to the pores. However, in the case of HS, BB, and LMW-O, as the molecular size decreased, these organic matters easily access to the pores inside of GAC. It was confirmed through the partition coefficient that the adsorption capacity of these NOM fractions increased in proportion to the MW. In addition, in order to achieve a high NOM removal efficiency in the GAC adsorption process, not only the specific surface area, pore volume, and pore width of the GAC must be large, but also the pHzpc must be higher than the neutral pH level.Conclusions:In order to achieve a high NOM removal efficiency in the GAC adsorption process, not only the specific surface area, pore volume, and pore width of the GAC must be large, but also the pHzpc must be higher than the neutral pH level. In addition, in the NOM fractions, BP were not adsorbed to GAC, while the adsorption capacity of the remaining NOM fractions increased as the MW of the NOM fractions decreased. LMW-O was the most adsorbed, followed by BB, HS and BP. BP and HS play an important role in the membrane fouling that are introduced a lot into domestic and foreign water treatment plants. This study showed that the BP was not removed by the adsorption mechanism of the GAC process. In addition, HS was adsorbed and removed at the beginning of the operation, but the adsorption capacity of HS decreased rapidly as the operation period increased compared to other NOM fractions. Therefore, the GAC adsorption process is not expected to be an effective pre-treatment technology for reducing membrane foulants. Previous studies showed that the yields of DBPs (µmol･DBP/µmol･C) in the high MW humic and low MW non-humic fractions are similar. Therefore, it is suggested that the GAC adsorption process is more effective for DBP precursor control in water containing a larger percentage of LMW NOM.

N,N-Dimethylhydrazine ((CH3)2–N–N–) compounds in water produce toxic N-nitrosodimethylamine (NDMA) during ozonation, thus need removing from water before ozonation. Chlorination can degrade N,N-dimethylhydrazines to give products that do not form NDMA during ozonation, but the chemistry is poorly understood. We studied the kinetics of and mechanisms involved in reactions between free available chlorine (FAC) and unsymmetrical dimethylhydrazine (UDMH) and daminozide (DMZ) (N,N-dimethylhydrazine compounds) and the efficiency with which FAC decreased the ozone–NDMA-formation potentials of UDMH and DMZ. FAC reacted quickly with UDMH (k = 4 × 105 M−1 s−1) and moderately with DMZ (k = 66 M−1 s−1) at pH 7. Formaldehyde and methanol were the main UDMH and DMZ degradation products, and succinic acid was also an important DMZ degradation product. Negligible NDMA formed (

The efficiency of elimination of organic UV filters by ozonation and UV254nm/H2O2 processes was assessed and predicted in simulated treatments of sewage-impaired drinking water and wastewater effluent in bench-scale experiments. Second-order rate constants (k) for the reactions of the eight UV filters with ozone and OH were determined by quantum chemical calculations and competition kinetics methods, respectively. The UV filters containing phenolic (ethylhexyl-salicylate, homosalate, and benzophenone-3) and olefinic moieties (4-methylbenzylidene-camphor, benzyl-cinnamate, and 2-ethylhexyl-4-methoxycinnamate) showed high ozone reactivity (k ≥ 8 × 104 M−1s−1 at pH 7), while those without such electron-rich moieties (isoamyl-benzoate and benzophenone) were ozone-refractory. All the UV filters showed high OH reactivity (k ≥ 6.2 × 109 M−1s−1). In concordance with the rate constant information, the phenolic and olefinic UV filters were efficiently eliminated by ozone treatment, requiring specific ozone doses of OH was the main contributor to their elimination in the UV254nm/H2O2 treatment. A chemical kinetics approach developed previously for ozonation and UV/H2O2 processes was shown to predict the elimination of the UV filters in the tested water matrices reasonably well, demonstrating that the chemical kinetics method can be used for a priori prediction of micropollutant elimination in oxidative treatment processes for potable reuse of municipal wastewater effluents.

The goal of this study was to investigate the occurrence and removal of 52 organic micropollutants (OMPs) during each wastewater treatment step in a full-scale wastewater treatment plant (WWTP). Pharmaceuticals such as metformin, acetaminophen, caffeine, ibuprofen, cimetidine and naproxen were found with high average concentrations in the influent. Most OMPs were not affected by the primary treatment (removal10%), while secondary biological treatment contributed the most to overall removal of the OMPs. Among the three lanes of the secondary treatment of the WWTP, a combined anaerobic-anoxic-oxic process followed by a membrane bioreactor (A2O-MBR) process effectively facilitated removal of the OMPs (96%) using a different redox: a conventional activated sludge (CAS) process exhibited removal of approximately 85% of total concentrations of the OMPs, while a Modified Ludzack-Ettinger (MLE) process achieved approximately 92.1% removal. Removal of more than 50% of the concentrations of 13 targeted OMPs was observed in the secondary effluent (except for metformin showing only 3.8% removal) via adsorption with powdered activated carbon (PAC) as additional tertiary treatment. Metformin, inadequately removed by additional tertiary treatments, was effectively removed by a biological activated carbon (BAC) process, reaching a removal efficiency of 90.5%. To increase the removal of the amounts and types of OMPs with various physico-chemical properties, hybrid processes through a combination of diverse advanced treatment should be tailored to WWTPs.

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.

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.

PBDEs (polybrominated diphenyl ehters) are rarely dissolved in water due to their strong hydrophobicity and large molecular mass so not many researches were done in aqueous environment compared to other environmental compartments. However, the mass loading from wastewater treatment plant into aquatic environment, re-suspension from bottom sediment and partitioning from floating particles and colloids may not be negligible. It is, therefore, important but also difficult to investigate PBDEs in water environment. Recent overcoming resolution towards this barrier to monitor hydrophobic organic compounds in aquatic environment is using passive sampling technique like semipermeable membrane device. By using passive sampling, it might be possible to obtain long-term reproducible monitoring result and detect the trace amounts of PBDEs, with controlling fluctuation of surrounding environmental factors during the sampling event. So therefore, this study is purposed to confirm the possibility of using SPMD (semi-permeable membrane device) as water monitoring tool. Grab samples, composite samples and SPMDs were applied in river bank to evaluate the concentration difference and temporal fluctuation by various water sampling method, and to assess the water concentration prediction capability of SPMD for the PBDEs.

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

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.

Effects of coagulation types on flocculation were investigated by using a photometric dispersion analyzer (PDA) as an on-line monitoring technique in this study. Nakdong River water were used and alum and ferric chloride were used as coagulants. The aim of this study is to compare the coagulation characteristics of alum and ferric chloride by a photometric dispersion analyzer (PDA). Floc growing rates (R v ) in three different water temperatures (4 ℃ , 16 ℃ and 30 ℃ ) and coagulants doses (0.15 mM, 0.20 mM and 0.25 mM as Al, Fe) were measured. The floc growing rate (R v ) by alum was 1.8 ∼ 2.8 times higher than that of ferric chloride during rapid mixing period, however, for 0.15 mM ∼ 0.25 mM coagulant doses the floc growing rate (R v ) by ferric chloride was 1.1 ∼ 2.3 times higher than that of alum in the slow mixing period at 16 ℃ water temperature. Reasonable coagulant doses of alum and ferric chloride for turbidity removal were 0.1 mM (as Al) and 0.2 mM (as Fe), respectively, and the removal efficiency of those coagulant doses showed 94% for alum and 97% for ferric chloride. The appropriate coagulant dose of alum and ferric chloride for removing dissolved organic carbon (DOC) showed about 0.3 mM (as Al, Fe) and at this dosage, DOC removal efficiencies were 36% and 44%, and ferric chloride was superior to the alum for removal of the DOC in water.

The aims of this study were to investigate and confirm the occurrence and distribution patterns of blood lipid lower agents (BLLAs) in Nakdong river basin (mainstream and its tributaries). 4 (atorvastatin, lovastatin, mevastatin and simvastatin) out of 5 statins and 2 (clofibric acid and zemfibrozil) out of 3 fibrates were detected in 29 sampling sites and simvastatin (>50%) was predominant compound followed by atorvastatin, lovastatin and clofibric acid. The total concentration levels of BLLAs on April, August and November 2009 in surface water samples ranged from ND ∼ 25.7 ng/L, ND ∼ 18.8 and ND to 38.8 ng/L, respectively. The highest concentration level of BLLAs in the mainstream and tributaries in Nakdong river were Goryeong and Jincheon-cheon, respectively. The sewage treatment plants (STPs) along the river affect the BLLAs levels in river and the BLLAs levels decreased with downstream because of dilution effects. Key words : Blood lipid lower agents, Statin class, Fibrate class, Main stream, Tributary, Nakdong river basin

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.

In this study, three different synthetic musk compounds (SMCs) in the Nakdong river water (raw water) and rapid sand filtered water were treated by O3 process. The experimental results showed that the removal efficiency of musk ketone (MK) was lower than removal efficiency of AHTN (7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene) and HHCB (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[c]-2-benzopyran) for both the raw water and the rapid sand filtered water. And in general, the removal efficiencies of three SMCs in the raw water were lower than that in the sand filtered water. Under the O3 dose of 0.5~ 10.0 mg/L, the removal rate constants (k) of three SMCs for the raw and sand filtered waters increased rapidly with the increased O3 dose. In the case of drinking water treatment plants (DWTPs) which were selected preand post-O3 processes (located in the downstream of Nakdong River), operation conditions of preand post-O3 process were 0.5~2.0 mg・O3/L (2~4 min) and 0.5~2.5 mg・O3/L (6~8 min). Therefore, O3 doses and contact times of same conditions with above were very difficult to remove SMCs in DWTPs.