정호찬 Ho Chan Jung , 정철중 Cheol Joong Jung , 송자연 Ja Yeon Song , 김연국 Youn Kook Kim , 이선용 Sun Yong Lee

DOI: Vol.28(No.5) 639-645, 2012

The purpose of this study is to identify the possibility of the CMP wastewater treatment from semiconductor fabrication under operating tubular membrane with coagulants. To find suitable coagulants treating CMP wastewater, we conducted Jar-test. After Jar-test experiments suitable coagulants are PAC(17%), Ca(OH)2 and optimum coagulant dosage is PAC(17%) 10mg/L, Ca(OH)2 110~120mg/L. Based on these results, the tubular membrane was applied to CMP wastewater, the turbidity removal efficiency is Ca(OH)2 > PAC(17%) > Nothing. The fast cross-flow velocity and backwash process what are operating characteristics of tubular membrane can be stable CMP wastewater treatment. But when the coagulant and tubular membrane are used at the same time, the withdraw and treatment of the CMP wastewater are possibile. However further treatment process needs if treated water will be used for semiconductor fabrications.

CMP wastewater, Coagulant, Semiconductor wastewater, Tubular membrane, Wastewater, Treatment

신유리 Yu Ri Shin , 장정렬 Jeong Ryeil Jang , 최정훈 Jung Hoon Choi , 조영권 Young Kweon Cho

DOI: Vol.28(No.5) 646-656, 2012

This study area was Saemangeum Reservoir in Korea and the applied model was Environmental Fluid Dynamics Code(EFDC). It was the same as the scenarios to the boundary and initial conditions except the resolutions of the model grids. The resolutions were about 800 and 2,000 cells. It was considered scenario 1 and 2. The model was performed to simulate the water temperature, salinity, water quality parameters such as dissolved oxygen(DO), chemical oxygen demand(COD), total nitrogen(T-N), and total phosphorus(T-P) at 2008. The simulation results of the two scenarios were reflected in the trend of observed data tolerably. However, water flow, water temperature, and salinity showed high confidence level at the scenario 1. The water quality items did not present high confidence level at the scenario 1 because which concept was considered to biochemical and physical processes. This result shows that grid resolution has an influence on the water transport and the effect is reflected directly shallow and narrow water area. But, the selection of grid resolution should be considered the purpose of model simulation and the process of target items.

EFDC, Grid resolutions, Saemangeum, Salinity, Water temperature, Water quality

정수정 Soo Jung Jung , 나숙현 Suk Hyun Na , 배상옥 Sang Ok Bae , 임병진 Byung Jin Lim

DOI: Vol.28(No.5) 657-662, 2012

This study was carried out to evaluate the removal rate of organic and inorganic matters from landfill leachate using pre-treatment process as coagulation and limonite adsorption, and membrane process as RO(reverse osmosis) and NF(nanofiltration). By adding limonite adsorption as pre-treatment process, about 40% of organic matters in leachate was removed through pre-treatment process and 74.7% of boron was removed after RO process without pH adjustment. The rejection rate of boron in RO process mainly depends on the pH and increased at pH value of 10. RO process was performed as two stage system adjusting pH condtion to 7 and 10 in second RO stage for boron removal. Most(>90%) of TOC, Cl- and inorganic matters as Ca was rejected in first RO stage, the residue was rejected in second RO and the rejection rate was above 97%. Considering economic efficiency of operation cost, NF substituted for the first RO and total removal rate of TOC was above 90%. Through RO system toxicity to Daphnia in leachate was removed completely.

Boron removal, Landfill leachate, Limonite adsorption, Nanofiltration, Reverse osmosis, Toxicity reduction

이몽학 Mong Hak Lee , 안조환 Jo Hwan Ahn , 이정훈 Jung Hun Lee , 배우근 Woo Keun Bae , 심호재 Ho Jae Shim

DOI: Vol.28(No.5) 663-668, 2012

The feasibility of enhancing biological nutrient removal from an industrial wastewater was tested with food waste leachate and sugar liquid waste as external carbon sources. Long term influences of adding external carbon sources were investigated to see how the biological nutrient removal process worked in terms of the removal efficiency. The addition of the external carbons led to a significant improvement in the removal efficiency of nutrients: from 49% to approximately 76% for nitrogen and from 64% to around 80% for phosphorus. Approximately, 20% of the removal nitrogen was synthesized into biomass, while the remaining 80% was denitrified. Though the addition of external carbon sources improved nutrient removal, it also increased the waste sludge production substantially. The optimal observed BOD/TN ratio, based on nitrogen removal and sludge production, was around 4.0 in this study.

Biological nutrient removal, External carbon source, Food waste leachate, Industrial wastewater, Sugar liquid waste

박송인 Song In Park , 정선용 Seon Yong Chung , Saido Kstsuhiko , Sato Hideto , 나숙현 Suk Hyun Na

DOI: Vol.28(No.5) 669-675, 2012

Recently, there have been active researches regarding endocrine-disrupting chemicals (EDCs). In this study, fifteen small freshwater streams in Cholla-namdo province, South Korea were investigated with respect to the concentration of the endocrine disruptors - Bisphenol A (BPA), styrene monomer (SM), styrene dimer (SD), and styrene trimer (ST) by gas chromatography-mass spectrometry (GC-MS). Measured concentration of the target compounds in the sampled water ranged from

Bisphenol A, Endocrine-disrupting chemicals, Freshwater streams, GC/MS, Styrene oligomer

김창수 Chang Soo Kim , 성기준 Ki June Sung

DOI: Vol.28(No.5) 676-685, 2012

As impermeable layer continues to increase with the urbanization process, direct input of nonpoint source pollutants into water bodies via stormwater has caused serious effects on the aquatic ecosystem. Potential applications of rain gardens are increasing not only as best management practices (BMP) for reducing the level of nonpoint source pollutants but also as an ecological engineering alternative for low impact development (LID). In this study, remediation performance of various planting types, such as a mixed planting system with shrubs and herbaceous plants, was assessed quantitatively to effectively manage stormwater and increase landscape applicability. The mixed planting system with Rhododendron lateritium and Zoysia japonica showed the highest removal performance of 76.9 ± 7.6% and 58.4 ± 5.0% for total nitrogen and 89.9 ± 7.9% and 82.4 ± 5.2% for total phosphorus at rainfall intensities of 2.5 mm/h and 5.0 mm/h, respectively. The mixed planting system also showed the highest removal performance for heavy metals. The results suggest that a rain garden with the mixed planting system has high potential applicability as a natural reduction system for nonpoint source pollutants in order to manage stormwater with low concentrations of pollutants and will increase water recycling in urban areas.

BMP, Heavy metals, LID, Mixed planting type, Nutrients, Stormwater management

조선주 Seon Ju Cho , 김상단 Sang Dan Kim

DOI: Vol.28(No.5) 686-692, 2012

This study illustrates how to design and evaluate a non-point sources management detention pond using SWMM. In particular, special attention is given to the orifice design. In SWMM, orifice properties that need to be defined include its height above the bottom of the storage unit, its type, its geometry and its hydraulic properties. Among the various characteristics of orifice, the orifice hole size which is closely related to hydraulic retention time is focused in this study. Sensitivity analysis of orifice size in annual non-point sources reduction efficiency is carried out. In addition, a methodology which can be used to design a virtual junction in SWMM has been proposed to quantify water quality improvement triggered by the detention pond installation. As a result, it is recommended that a detention outlet should be designed to be about 2 to 3 days of hydraulic retention time.

Detention, Non-point sources, Orifice, SWMM, Urban hydrology

박준대 Jun Dae Park , 오승영 Seung Young Oh

DOI: Vol.28(No.5) 693-703, 2012

Load Duration Curve(LDC) is a useful tool for analyzing water quality characteristics under various stream flow conditions. This study investigated the methods to identify impaired waterbodies in the assessment of water quality goal attainment by using LDC for the management of Total Maximum Daily Loads (TMDLs). Three methods were proposed. Non-typical regime exclusion method is a method to exclude water quality observations in the non-typical extreme flow conditions in order to minimize the influence of non-ordinary water quality. Flow regime weighted average method is a method to calculate weighted mean water quality instead of arithmetic mean in order to consider water characteristics properly on stream flow regime in addition to the effect of Non-typical regime exclusion method. Load exceeded interval comparison method is a method to compare the intervals between the attained and non-attained load duration periods on the LDC. The assessment of water quality goal attainment can be performed more reasonably and precisely considering water quality variations on stream flow conditions by applying these proposed methods.

Load Duration Curve, LDC, Stream flow conditions, Total Maximum Daily Loads (TMDLs), Water quality characteristics, Water quality goal attainment

Stephen R. Mcadams , 구본진 Bon Jin Koo , 장명훈 Myung Hoon Jang , 이성규 Sung Kyoo Lee

DOI: Vol.28(No.5) 704-716, 2012

This paper provides a detailed account of pilot testing conducted at South Lake Tahoe (California), the Ddukdo (Seoul) water treatment plant (WTP) and the Bokjung (Seongnam) WTP between February, 2010, and February, 2012. The objectives were first, to characterize the reactions of ozone with hydrogen peroxide (Peroxone) for Han River water following sand filtration, second to determine empirical ozone and hydrogen peroxide doses to remove a taste-and-odor surrogate 2-methylisoborneol (MIB) using an advanced oxidation process (AOP) configuration and third, to determine the optimum dosing configuration to reduce residual ozone to a safe level at the exit of the process. The testing was performed in a real-time plant environment at both low- and high seasonal water temperatures. Experimental results including ozone decomposition rates were dependent on temperature and pH, consistent with data reported by other researchers. MIB in post-sand-filtration water was spiked to 40-50 ng/L, and in all cases, it was reduced to below the specified target level (7 ng/liter) and typically non-detect (ND). It was demonstrated that Peroxone could achieve both MIB removal and low effluent ozone residual at ozone+hydrogen peroxide doses less than those for ozone alone. An empirical predictive model, suitable for use by design engineers and operating personnel and for incorporation in plant control systems was developed. Due to a significant reduction in the ozone reaction/decomposition at low winter temperatures, results demonstrate the hydrogen peroxide can be “pre-conditioned”1) in order to increase initial reaction rates and achieve lower ozone residuals. Results also indicate the method, location and composition of hydrogen peroxide injection is critical to successful implementation of Peroxone without using excessive chemicals or degrading performance.

AOP, Han river, Hydrogen peroxide, Ozone, Peroxone, taste-and-odor

최정수 Jung Su Choi , 주현종 Hyun Jong Joo , 진오석 Oh Suk Jin

DOI: Vol.28(No.5) 717-722, 2012

Fluoride can be easily found in semiconductor and display industry. However, there is a lack of research for its effects on the related wastewater treatment. The objective of this study is to evaluate the microbial inhibitory effect by fluoride injection. The research entailed the assessment of removal efficiency of TCOD(Cr) according to the fluoride concentration and also the Specific Oxygen Uptake Rate (SOUR) was measured. The laboratory scale reactor was prepared and operated with the fluoride concentrations of 0, 10, 50, 100, and 200 mg/L based on concentrations frequently occurring in the wastewater. The results from this study showed that, as the fluoride concentration increase, the Specific Substrate Utilization Rate (SSUR) tend to decrease as expected. Also, the increase in fluoride concentrations resulted in the decrease in SOUR. It is determined that fluoride injection affects the microbial activity. Especially, The addition of above 200 mg/L fluoride into reactor caused rapidly decreased SSUR and SOUR due to the inhibitory effects of fluoride.

Fluoride, Microbial activity, Specific oxygen uptake rate, Specifie substrate utilization rate

이창한 Chang Han Lee

DOI: Vol.28(No.5) 723-728, 2012

In this study, zeolites were synthesized by a fusion and a hydrothermal methods using a coal fly ash and a waste catalyst. The recovery performance of metal ions on the structure property of synthetic zeolites was evaluated as comparing the adsorption kinetics (Lagergen 2nd order model) and isotherm (Langmuir model) of Co2+, Ni2+, and Cu2+ ions. The synthetic zeolites (Z-C1 and Z-W5) were similarly assigned to XRD peaks in a reagent grade Na-A zeolite (Z-WK: Na12Al12Si12O4827.4H2O). Adsorption rates of Z-W5 and Z-C1 were in the order of Cu2+ > Co2+ > Ni2+ and Ni2+ > Cu2+ > Co2+, respectively. They had influenced upon structure properties of zeolite. Selectivities of metal ions and maximum equilibrium adsorption capacities, q(max), in Z-C1 and Z-W5 were in the order of Ni2+(127.9 mg/g) > Cu2+(94.7 mg/g) > Co2+(82.6 mg/g) and Cu2+(141.3 mg/g) > Co2+(122.2 mg/g) > Ni2+(87.6 mg/g), respectively. The results show that the synthetic zeolites, Z-C1 and Z-W5, are able to recover metal ions selectively in wastewater.

Catalyst, Fly ash, Metal, Recovery, Synthesis, Zeolite

최충호 Choong Ho Choi , 맹승규 Sung Kyu Maeng , 심재휘 Jae Hwi Sim , 최진호 Jin Ho Choi , 송경근 Kyung Guen Song , 이병하 Byung Ha Lee , 차호영 Ho Young Cha

DOI: Vol.28(No.5) 729-742, 2012

Recently, to using chemical coagulation process for T-P removal in STP effluent as tertiary treatment process is generalized in the country. The importance of analysis technique to save the treatment & maintenance cost during coagulation process is becoming more increased each day. Thus, it is necessary for the analysis technique during coagulation process to be presented well the characteristic of coagulation in field apply. There are a few analysis techniques such as Jar Test, zeta potential analysis and streaming current detecting techniques. But there are difficult to apply in field immediately due to long test time and difficult analysis techniques. And using PDA technique, it is reviewed applicability of the techniques as field index on pilot plant of P-CAP system The P-CAP system is composed of an in-line static mixer, a Flocculation Tank and the CAP reactor with 2 stage weir for effluent. Pre-test is performed to fix the mixing velocity in the Flocculation Tank using the PDA equipment and it fixed with 30RPM. Also, Jar Test is performed to select optimum dose of each coagulant for each T-P concentration level of influent. Result of continuous test on pilot plant of P-CAP system, the FSI in the Flocculation Tank is increased consistently by increasing each dosing concentration of coagulant such as LAS and PAC in the low level influent T-P concentration comparatively. It is considered that formed Al-hydroxide complexes for dosed coagulant are caused FSI variation. Furthermore, it seems that FSI value in the high level influent T-P concentration appeared lower than the opposite influent condition relatively because it is formed simultaneously Al-hydroxide complexes as solid type and Al-phosphorus complexes as soluble type. Thus, relation of FSI by PDA technique and T-P removal of final effluent on pilot plant of P-CAP system are very limited for the kind of coagulant and the characteristics of influent. And it though that FSI value by PDA technique with analyzing of turbidity in Flocculation Tank will be used restrictedly on field as the relative field-index.

Coagulation, LAS, PAC, P-CAP, PDA, T-P

류지철 Ji Chul Ryu , 최재완 Jae Wan Choi , 강현우 Hyun Woo Kang , 금동혁 Dong Hyuk Kum , 신동석 Dong Suk Shin , 이기환 Ki Hwan Lee , 정교철 Gyo Cheol Jeong , 임경재 Kyoung Jae Lim

DOI: Vol.28(No.5) 743-753, 2012

The hydrologic models, capable of simulating groundwater recharge for long-term period and effects on it of crops management in the agricultural areas, have been used to compute groundwater recharge in the agricultural fields. Among these models, the Soil and Water Assessment Tool (SWAT) has been widely used because it could interpret hydrologic conditions for the long time considering effects of weather condition, land uses, and soil. However the SWAT model couldn`t represent the spatial information of Hydrologic Response Unit (HRU), the SWAT HRU mapping module was developed in 2010. With this capability, it is possible to assume and analyze spatio-temporal groundwater recharge. In this study, groundwater recharge of rate for various crops in the Mandae stream watershed was estimated using SWAT HRU Mapping module, which can simulate spato-temporal recharge rate. As a result of this study, Coefficient of determination (R2) and Nash-Sutcliffe model efficiency (NSE) for flow calibration were 0.80 and 0.72, respectively, and monthly groundwater recharge of Mandae watershed in Haean-myeon was 381.24 mm/year. It was 28% of total precipitation in 2009. Groundwater recharge rate was 73.54 mm/month and 73.58 mm/month for July and August 2009, which is approximately 18 times of groundwater recharge rate for December 2009. The groundwater recharges for each month through the year were varying. The groundwater recharge was smaller in the spring and winter seasons, relatively. So, it is necessary to enforce proper management of groundwater recharge during droughty season. Also, the SWAT HRU Mapping module could show the result of groundwater recharge as a GIS map and analyze spatio-temporal groundwater recharge. So, this method, proposed in this study, would be quite useful to make groundwater management plans at agriculture-dominant watershed.

Agricultural field, Groundwater, Recharge rate, SWAT HRU Mapping module

이연희 Youn Hee Lee , 박주현 Ju Hyun Park , 김현구 Hyun Koo Kim , 안경희 Kyung Hee Ahn , 김태승 Tae Seung Kim , 김동훈 Dong Hoon Kim , 권오상 Oh Sang Kwon

DOI: Vol.28(No.5) 754-761, 2012

Several drinking water treatment plants (DWTPs) produce the bottled tap waters (BTWs) as pilot production and provide them for noncommercial use. In 2008, acetaldehyde and chloral hydrate were detected in some BTWs and the public worry over the safety of the water. In this study, the BTWs produced from 7 DWTPs were tested for 13 chemicals including disinfection byproducts (DBPs). The level of four trihalomethanes (THMs) were increased up to 15 days. The average concentration of them was 0.0075 mg/L at the time of bottling and it was increased to 0.0214 mg/L after 15 days. The average acetaldehyde concentration was 0.0406 mg/L at the time of bottling but it was went up to 0.2251 mg/L after 11 days and then decreased. Although the initial concentrations of DBPs were below the drinking water standard, we also traced them at different storage conditions. Temperature affected the formations of THMs and acetaldehyde concentrations significantly. While the average concentration of THMs ranged from 0.0113 to 0.0182 mg/L at 25°C, it was increased to 0.0132~0.0256 mg/L at 50°C. In case of acetaldehyde, concentration ranged from 0.0901 to 0.2251 mg/L at 25°C, it was increased to 0.3394~1.0591 mg/L at 50°C. Throughout the tests with 7 BTWs samples, none of the chemicals was exceeded the drinking water standard of Korea. Therefore, it is recommended to avoid the exposure of BTWs to sunlight or high temperature during distribution and storage.

Acetaldehyde, Bottled tap water Chloral hydrate, Disinfection by-products, Formaldehyde, PET

신유진 Yu Jin Shin , 안윤주 Youn Joo An

DOI: Vol.28(No.5) 762-767, 2012

The ecotoxicity assessment of nanomaterials (NMs) in the environment is actively conducted throughout the world because of the concerns about their potential risk from usage and release into the environment, as well as their unique physiochemical properties. Ecotoxicity tests for NMs have been conducted using various species and methods; however, in spite of these efforts, the characteristics and toxicity of NMs have not been defined. The fish embryo toxicity test (FET) has been conducted extensively to evaluate the toxicity of NMs as an alternative to a whole-body test in fish. In this study, we collected and analyzed the trends of nanotoxicity on the early development of freshwater fish. The model nanomaterials are carbon NMs (C60, C70, C60(OH)n and carbon nanotube). Their adverse effects were extensively investigated based on the properties of NMs, test species, and diverse exposure conditions.

Carbon, Dendrimer, Embryonic development, Fish embryo toxicity tests, FETs, Nanomaterials, Nanotoxicity, Polymer