Hoon-Sik Yeom

Evaluation of Applicability and Economical Efficiency of Peroxone Process for Removal of Micropollutants in Drinking Water Treatment

Abstract We compared the applicability and economical efficiency of peroxone process with those of ozone process in the existing water treatment plant on downstream of Nakdong River. After comparing the peroxone process for removing geosmin with the ozone process in lab scale test, peroxone process showed much higher removal efficiency than the ozone process at the same ozone dosage. Proper range of H 2 O 2 /O 3 ratio were 0.5~1.0 and the half-life of geosmin was about 5.5~6.8 min when the H 2 O 2 /O 3 ratio was set to 0.5 during 1~2 mg/L of ozone dosage. Peroxone process could reduce the ozone dosage about 50 to maximum 30% for the same geosmin removal efficiency compared to the ozone process in the pilot scale test. In case of 1,4-dioxane treatment, peroxone process could have 3~4 times higher efficiency than ozone process at the same ozone dosage. The results of estimating the economical efficiency of ozone and peroxone process for treating geosmin and 1,4-dioxane by using pilot scale test, in case of the removal target was set to 85% for these two materials, the cost of peroxane process could be reduced about 1.5 times compared to ozone process, and in the same production cost peroxone process could have 2~3 times higher removal efficiency than ozone process. The removal efficiency by peroxone process showed a large difference depending on the physicochemical characteristics of target materials and raw water, therefore detailed examination should be carried out before appling peroxone process. Key words: Peroxone process, Geosmin. 1,4-dioxane, Drinking water treatment, Economical efficiency

Application of Enhanced Coagulation for Nakdong River Water Using Aluminium and Ferric Salt Coagulants

Enhanced coagulation is best available technologies to treat NOM in water to produce clean drinking water. In this research, the comparison experiments between conventional coagulation (CC) and enhanced coagulation (EC) using 4 type coa- gulants i.e., ferric chloride, aluminium sulphate (alum), poly aluminium sulphate organic magnesium (PSOM) and poly aluminium chloride (PACl) were performed in terms of surrogate parameters such as dissolved organic carbon (DOC), trihalomethane formation potential (THMFP), haloacetic acid formation potential (HAAFP) and zeta potential variation in order to find out the most effective coagulant and conditions to fit Nakdong River water. When applied to EC process, the turbidity removal efficiency did not increased gradually compared to the CC process when adding coagulants. Furthermore, the removal efficiency of turbidity became decreased much more as coagulants were added increasingly whereas the removal efficiency of DOC, THMFP and HAAFP became increased by 13~18%, 9~18% and 9~18% respectively compared to the CC process. The characteristics of turbidity removal showed relatively high removal efficiency considering the pH variation in entire pH range when using FeCl3 and PACl. Additionally, in case of alum and PSOM steady removal efficiency was shown between pH 5 and pH 8. In terms of DOC surrogate the coagulants including 4 type coagulants indicated high removal efficiency between pH 5 and pH 7. The removal efficiency of dissolved organic matter (DOM) in EC between less than 1 kDa and more than 10 kDa augmented by 11~21% and 16% respectively compared to the CC process. The removal efficiency of hydrophobic and hydrophilic organic matter proved to be increased by 27~38% and 11~15% respectively. In conclusion, the most effective coagulant relating to EC for Nakdong River water was proved to be FeCl3 followed by PSOM, PAC and alum in order.

Caffeine and Carbamazepine: Detection in Nakdong River Basin and Behavior under Drinking Water Treatment Processes

Abstract The aims of this study were to investigated the occurrence of caffeine and carbamazepine in Nakdong river basin (8 mainstreams and 2 tributaries) and the behavior of caffeine and carbamazepine under drinking water treatment processes (conventional and advanced processes). The examination results showed that caffeine was detected at all sampling sites (5.4 ∼ 558.5 ng/L), but carbamazepine was detected at five sampling sites (5.1 ∼ 79.4 ng/L). The highest concentration level of caffeine and carbamazepine in the mainstream and tributaries in Nakdong river were Goryeong and Jinchun-cheon, respectively. These pharmaceutical products were completely removed when they were subject to conventional plus advanced processes of drinking water treatment processes. Conventional processes of coagulation, sedimentation and sand-filtration were not effective for their removal, while advanced processes of ozonation and biological activated carbon (BAC) filtration were effective. Among these pharmaceuticals, carbamazeoine was more subject to ozonation than caffeine.

Evaluation of Adsorption Characteristics of Radioactive Iodine (I-131) for Various Materials of Granular Activated Carbon (GAC)

Abstract This research was performed by means of several different virgin granular activated carbons (GAC) made of each coal, coconut and wood, and the GACs were investigated for an adsorption performance of iodine-131 in a continuous adsorption column. Breakthrough behavior was investigated that the breakthrough points of the virgin two coals-, coconut- and wood-based GACs were observed as bed volume (BV) 7080, BV 5640, BV 5064 and BV 3192, respectively. The experimental results of adsorption capacity (X/M) for iodine-127 showed that two coal- based GACs were highest (208.6 and 139.1 μg/g), the coconut-based GAC was intermediate (86.5 μg/g) and the wood-based GAC was lowest (54.5 μg/g). The X/M of the coal-based GACs was 2∼4 times higher than the X/M of the coconut-based and wood-based GACs. Key words : Iodine-131, Radionuclide, Granular activated carbon (GAC), Adsorption. 1. 서 론 1) 수중에 함유되어 있는 방사성 물질은 물을 직접 음용함으로서 인체 내로 유입되거나 또는 수중에 서식하는 생물들의 먹이 사슬을 통한 간접적인 방법으로 인체에 흡수될 수 있다. 요오드(I)는 갑상선 호르몬 성분으로 인간과 동물에 필수적인 원소이며, 자연 상태에서는 I-127과 I-129의 동위원소로 이루어져 환경 중에 흔하게 존재한다. 그러나 I-131은 자연 상태에서는 존재하지 않고, 우라늄의 핵분열 과정에서 발생하며, 핵사고시에 환경 중으로 방출되는 매우 위험한 인공 방사성핵종으로 1986년 4월 23일 체르노빌 원전사고 후 원전 주위에서 갑상선암 발병의 증가가 확인되었다(Goossens 등, 1989). 2011년 3월 일본 대지진으로 도쿄 전력의 후쿠시마 다이치 원전의 폭발로 인해 많은 양의 인공방사성핵종이 환경중으로 방출되었으며(Ikemoto와 Magara, 2011), 환경 중으로 방출된 주요 방사성핵종은 Te-132(반감기, 77 hr), Te-131(반감기, 24.8 min) 그리고 그들의 딸핵인 I-131(반감기, 8.05 day), Cs-134(반감기, 2.06 yr), Cs-137(반감기, 30 yr)이었으며, 원전 폭발 후에 I-131이 일본의 먹는물(수돗물)에서 검출되었다(Ikemoto와

Detection Characteristics of Blood Lipid Lower Agents (BLLAs) in Nakdong River Basin

Abstract 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

Decomposition of Microcystis sp. Cell and Formation of Chlorination Disinfection By-Products

Formation of disinfection by-products (DBPs) including trihalomethans (THM), haloacetic acid (HAA) and haloacetonitriles (HAN) from chlorination of extracellular organic matter (EOM) and cells + intracellular organic matter (IOM) of Microcystis sp., a blue-green algae, during decomposed period was investigated. Microcystis sp. cells + IOM and EOM of Microcystis sp. exhibited a high potential for DBP formation. HAAFP (formation potential) was higher than THMFP during decomposed period. In the variations of HAAFP species during decomposed period, the ratio of di-HAAFP species was gradually decreased and the ratio of tri-HAAFP species was gradually increased in the case of EOM during decomposed period, while the opposite result was in the case of cells + IOM during decomposed period. In the variations of HANFP species during decomposed period, the ratio of di-HANFP species was much higher than the ratio of tri-HAAFP species.

Development of Analytical Method and Monitoring of Organophosphorus Pesticides in the Raw Water and Clean Water by Liquid Chromatography-Tandem Mass Spectrometry

The analytical method for 16 organophosphorus pesticides was developed in this study. The 16 organophosphorus pesticides were analyzed by liquid chromatography-tandem mass spectrometry (LC/MS/MS) using on-line solid phase extraction (on-line SPE) with PLRP- S cartridge. Analysis of all analytes in the MS/MS was processed in the electrospray ioni-zation (ESI) positive mode. They are Azinphos ethyl, Chlorfenvinphos, Ethion, Famphur, Phosmet, Phosphamidon, Terbufos, Aspon, Chlorpyrifos-methyl, Crotoxyphos, Dichlofenthi-on, Dicrotophos, Fonofos, Thionazin, Dimethoate and Iprobenfos. Limits of detection (LODs) and Limits of quantification(LOQs) were obtained as 0.8~2.0 ng/L and 2.6~6.4 ng/L, respectively. All compounds were not detected at the 8 sampling points of the raw water and clean water.

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.

Formation of Disinfection By-Products from Blue-green Algae by Chlorination

Formation of disinfection by-products (DBPs) including trihalomethans (THMs), haloacetic acid (HAAs), haloacetonitriles (HANs) and others from chlorination of algogenic organic matter (AOM) of Microcystis sp., a blue-green algae. AOM of Microcystis sp. exhibited a high potential for DBPs formation. HAAs formation potential was higher than THMs and HANs formation potential. The percentages of dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) formation potential were 43.4% and 51.4% in the total HAAs formation potential. In the case of HANs formation potential, percentage of dichloroacetonitrile (DCAN) formation potential was 97.7%. Other DBPs were aldehydes and nitriles such as acetaldehyde, methylene chloride, isobutyronitrile, cyclobutanecarbonitrile, pentanenitrile, benzaldehyde, propanal, 2-methyl, benzyl chloride, (2-chloroethyl)-benzene, benzyl nitrile, 2-probenenitrile and hexanal.