Jae Won Choi , Jae Hee Lee , Kyoung Sim Kim , Sun Heong Kim , Kyung Hee Baek

DOI: Vol.21(No.3) 219-229, 2005

The analytical methods for dioxins in water sample from wastewater to tap water were reviewed. For extraction method, liquid-liquid extraction (LLE) has been widely used, however, this process needs too much time and man power. New approach including solid phase extraction (SPE) is now applicable to large volume of water sample with high extraction efficiency. Column clean up in classical analytical methods were very complex and time consuming procedures during decade. Modifications were tried to decrease solvent and reagents volume. Moreover, use of column connection method has been demonstrated in the environmental matrices. Instrumental configurations also have been improved, in which GC/MS/MS with large volume injection approach can analyze picogram levels. Absolute sensitivities of HRMS increased compared to old versions of double focusing sector type mass spectrometers. Based on these analytical evolutions during last 10 years, we tried to optimize the analytical method for dioxins in water sample from sample extraction to instrumental analysis.

Dioxin, PCDD/F, Analysis, Toxicity equivalency factor, TEF, Toxic equivalent, TEQ, Tap water

정용준 Yong Jun Jung , 민경석 Kyung Sok Min

DOI: Vol.21(No.3) 230-235, 2005

The main purpose of the flocculation process is to make flocs bigger to be removed easily in the following processes. The flow pattern and mixing intensity have a great influence on flocculation. In this study, the flow pattern was examined by a hydraulic tracer-test, where 3 water treatment plants having 800,000 ㎥/d, 44,000 ㎥/d and 40,000 ㎥/d were employed. Also, the settling test was conducted to find out the relationship between the mixing intensity and the settling ability of flocs. The hydraulic tracer-test was conducted for the various flocculation processes that have different structures of flocculation basins. In the result, the retention time distribution (RTD) curves for the flocculation processes were quite different. In case of the inappropriate structure of the flocculation basin, the flow is not even so that the floc does not grow enough. To find out the relationship between mixing intensity and settleability of flocs, G-values were calculated and the settling test was conducted for two flocculation basins which have the same conditions except the G-value. For the flocculation basin with uneven G-value, the floc settleability was revealed poor. On the other hand, the flocculation basin with even G-value, the settleability was better than the previous one. From these experimental results, it is confirmed that the flow pattern is closely related to the structure of the flocculation basin and the settleability is affected by mixing intensity. Therefore the flow pattern and the strength of the mixing intensity should be examined sufficiently to design and operate flocculation basin.

Water treatment plant, Flocculation, Tracer-test, Flocculation strength, Settling test

이정만 Joung Man Lee , 박청길 Chung Kil Park , 김철 Chul Kim

DOI: Vol.21(No.3) 236-241, 2005

The purpose of this study is to find out the source(s) and distribution of boron in Nak-dong River. In the year of 2002, the boron has been adopted as a toxic constituent for Korean drinking water standard. In this study, the analytical samples were collected at 11 stations in March, June, September and December 2002. These samples were analyzed by inductively coupled plasma-mass (ICP-MS) method. The recovery, relative standard deviation and method detection limit of the ICP-MS method for boron was 89~111.3%, 2.21~3.81% and 5 μg/L, respectively. The distribution of boron was ranged 65~155 μg/L in March, 26~125 μg/L in June, 22~140 μg/L in September and 50~162 μg/L in December. The higher levels of boron were found at Kum-ho river nearby the industrial complex, which seemed to be greatly affected by domestic sewages and wastewater from the upper streams. Thus, the concentration of boron and that of other components showed strong statistical correlation in this area. In the Nak-dong River, industrial wastewater and domestic sewages is thought to be the sources of boron.

Boron, Nakdong river, Drink water, Water quality management

배진열 Jin Youl Bae , 한인섭 Ihn Sup Han , 박성호 Sung Ho Park , 신지원 Jee Won Shin

DOI: Vol.21(No.3) 242-247, 2005

In this study, we investigated the removal efficiencies of pollutants and permeate fluxes depending on chemistry of feed water, various molecular weight cut-offs (MWCOs) and materials of membrane, operating pressure. We used seven MWCO membranes of YC0.5, YM1, YM3, YM10, YM30, YM100 and PM30, humic acid solution and surface water as feed water, and examined variation in permeate flux. Results of TOC removal experiment demonstrate that MWCO lower 1,000daltons could remove humic acid effectively. As increasing solution pH and decreasing divalent cations (Ca^(2+)) concentration, TOC removal increased. But UV_(254) removal efficiency increased with higher divalent cation concentration and solution pH. Membrane fouling increased with increasing electrolyte (NaCl), divalent cation concentration and decreasing solution pH. In spite of initial permeate flux of the hydrophobic membrane (PM30) was higher than that of the hydrophilic membrane (YM30), flux decline of PM30 was significant during operation. At higher operating pressure, compactness of the cake layer on the membrane surface increased, resulting in gradual increase in hydraulic resistance.

Membrane fouling, Molecular weight cut-off, MWCO, Humic acid, Permeate flux, Flux decline, Hydraulic resistance

김이형 Lee Hyung Kim , 이선하 Seon Ha Lee

DOI: Vol.21(No.3) 248-255, 2005

Since the water quality of drinking water sources has been recognized as a big issue, the ministry of Environment in Korea is designing the total maximum daily load (TMDL) program for 4 major large rivers. The TMDL program can be successfully performed as controling the nonpoint pollutants from watershed area near the river. Of the various landuses in nonpoint pollution, parking lots and bridges are stormwater intensive landuses because of high imperviousness and high pollutant mass emissions from vehicular activities. Vehicle emissions from those areas include different pollutants such as heavy metals, oil and grease and particulates from sources such as fuels, brake pad and tire wear, etc. Especially the pollutant washed-off from the landuses are directly affecting to the river water quality. Therefore this research was conducted to understand the magnitude and nature of the stormwater emissions with the goal of quantifying stormwater pollutant concentrations and mass emission rates of pollutants from parking lot and bridges in Korea. In Kongju city areas, two monitoring sites were equipped with an automatic rainfall gages and an automatic flow meter for accumulating the useful data such as rainfall, water quality and runoff flow. This manuscripts will show the concentration changes during storm duration and EMCs to characterize the concentration profiles in different land uses. Also the first flush criteria will be suggested using dynamic EMCs. The definition of dynamic EMC is a new approach explaining the relationship of EMC and first flush effect.

Bridge, Dynamic EMCs, Land use, Nonpoint sources, Parking Lot

정진영 Jin Young Jung , 정윤철 Yun Chul Chung , 강신현 Shin Hyun Kang , 정형숙 Hyung Sook Chung

DOI: Vol.21(No.3) 256-262, 2005

The purpose of this study is to investigate the performances of organic removal and methane recovery by using a full scale two-phase anaerobic system. The full scale two-phase anaerobic process was consists of an acidogenic anaerobic baffled reactor (ABR) and a methanognic upflow anaerobic sludge blanket (UASB) reactor. The volumes of acidogenic and methanogenic reactors were designed to 28.3 ㎥ and 75.3 ㎥. The two-phase anaerobic system represented 60-82% of COD removal efficiency when the influent COD concentration was in the range of 7,150 to 16,270 ㎎/L after screening (average concentration is 10,280 ㎎/L). After steady-state, the effluent COD concentration in the methanogenic reactor showed 2,740±330 ㎎/L by representing average COD removal efficiency was 71.4±8.1% when the operating temperature was in the range of 19-32℃. The effluent SCOD concentration was in the range of 2,000-3,000 ㎎/L at the steady state while the volatile fatty acid concentration was not detected in the effluent. Meanwhile, the COD removal efficiency in the acidogenic reactor showed less than 5%. The acidogenic reactor played key roles to reduce a shock-loading when periodic shock loading was applied and to acidify influent organics. Due to the high concentration of alkalinity and high pH in the effluent of the methanogenic reactor, over 80% of methane in the biogas was produced consistently. More than 70% of methane was recovered from theoretical methane production of TCOD removed in this research. The produced gas can be directly used as a heat source to increase the reactor temperature.

Two-stage anaerobic system, Piggery wastewater, Methane recovery, COD removal, Methane content

박재홍 Jae Hong Park , 조일형 Il Hyoung Cho

DOI: Vol.21(No.3) 263-266, 2005

Comparison between photocatalysis (UV+TiO₂) and sonophotocatalysis (Sonication+UV+TiO₂) were performed in lab-scale experiments for the treatment of chloroform. The effect of operational parameters, i.e., initial chloroform concentration, TiO₂ concentration, UV light intensity and sonication time on the degradation rate of aqueous solution of chloroform has been examined. The optimal conditions for photocatalysis and sonophotocatalysis processes were determined: initial chloroform concentration was 25 ㎎/L, the concentration of TiO₂ was 200 ㎎/L and UV light intensity was 6.630 mW/㎠, respectively. The optimal sonication time on sonophotocatalysis process was 90 min. Under the optimal conditions, sonophotocatalysis was effective for inducing faster degradation of the chloroform.

Sonophotocatalysis, Photocatalysis, Chloroform

강태희 Tae Hee Kang , 오병수 Byung Soo Oh , 박세준 Sei Joon Park , 강민구 Min Gu Kang , 김종성 Jong Sung Kim , 강준원 Joon Wun Kang

DOI: Vol.21(No.3) 267-273, 2005

Dye wastewater generally contains strong color and non-biodegradable materials. Therefore, the conventional wastewater treatment plant can hardly meet the regulation of wastewater effluent water. In this study, a pilot plant of the conventional process followed by advanced oxidation process (AOP), was set up to treat the dying wastewater. The treatment efficiencies on the various candidate processes, such as ozone alone, UV alone, ozone/UV, ozone/H₂O₂, H₂O₂/UV and ozone/UV/H₂O₂, were investigated in the various ozone and H₂O₂ doses. As the results, the ozone/H₂O₂ process, among the tested processes, showed the highest efficiency for removing color and COD_(Cr). For color removal, the ozone alone process was enough without combining UV or H₂O₂. No significantly enhanced efficiency for removing color and COD_(Cr) by UV irradiation was observed because of the very low transmittance of UV light in dye wastewater.

Dye wastewater, Advanced oxidation process, AOP, Ozone, UV, Hydrogen peroxide

김상훈 S. H. Kim , 천세억 S. U. Cheon , 신기식 K. S. Shin , 정동일 D. I. Jung

DOI: Vol.21(No.3) 274-276, 2005

To investigate bioassay for toxic level evaluation of wastewater, toxic levels were checked influents and effluents of 6 wastewater discharge facilities with Daphnia magna and Vibrio fischeri. In view of test duration, D. magna is preferred at 48 hours. And it was judged to efficient that one of the two was choosen for toxicity test method (Daphnia test and Vibrio test). Analysis data for wastewater is average toxic level for influent more higher than effluent. And effluent toxic level is sharp decrease than effluents.

Bioassay, V. fischeri, D. magna, Influents, Effluents, Test duration, Test method

김종민 Jong Min Kim , 노혜란 Hye Ran Noh , 허성남 Seong Nam Heo , 양희정 Hee Jeong Yang , 박준대 Jun Dae Park

DOI: Vol.21(No.3) 277-283, 2005

This paper aimed to compare the daily water quality as well as the hydrological data gathered for the past two years (2000 to 2001) between the two influent rivers of Paldang reservoir. The analysis also has been carried out to draw out the factors that affect the water quality at the dam site, where the main drinking water drawing point is located. The relationship between total amount of monthly rainfall and monthly inflow showed r²=0.74 (p＜0.05). The highest peak of inflow of influent rivers recorded in August and September (in the year of 2000) and July and August (2001). Average inflows of influent rivers in 2000 and 2001 are calculated at 209.0, 161.5 CMS (Bughangang), 268.6, 148.2 CMS(Namhangang), and 7.8, 5.0 CMS (Gyeongancheon). The formula which was driven from the relationship between inflow and COD load of influent rivers, explained that COD concentration in general increased with the inflow. But during the rainy seasons (July, August, and September), COD concentration decreased according to the increase of inflow. The daily rainfall and COD concentration(or load) during the rainy season (August and September in the year of 2000, July and August in 2001) indicated that the peak of COD load correspond with the rainfall, which decreased sharply after 3 or 4 days. The reason was thought that the high COD load was diluted rapidly by the rain flow. Water temperature, pH and conductivity measured at dam site decreased obviously when the inflow sharply increased. Peak period of total phosphorus concentration coincided with that of inflow. In rainy season, chlorophyll-a concentration decreased obviously as the inflow increased. The reason can be ascribed to the flushing effect caused by the operation of floodgate.

Paldang reservoir, Rainfall, Influent river, COD

박재홍 Jae Hong Park , 장순웅 Soon Woong Chang , 조일형 Il Hyoung Cho

DOI: Vol.21(No.3) 284-288, 2005

In this study, photochemical advanced oxidation processes (AOPs) utilizing the Photo Fenton reaction (Fe^(2+)+H₂O₂+UV) were investigated in lab-scale experiments for the treatment of livestock wastewater. For the experimets, the livestock wastewater was pretreated by coagulation with 3,000 ㎎/L FeCl₃. The optimal conditions for Photo-Fenton processes were determined: pH was 5, the concentration of ferrous ion (Fe Ⅱ) was 0.01 M. The concentration of hydrogen peroxide was 0.1 M, and molar ratio (Fe^(2+)/H₂O₂) was 0.1. The optimal reaction time was 80 min. Under the optimal condition of Photo-Fenton process, chemical oxygen demand (COD), color and fecal coliform removal efficiencies were about 79, 70, and 99.4%, respectively and sludge production was 7.5 mL from 100 mL of solution.

Livestock wastewater, Photo-fenton process

권태옥 Tae Ouk Kwon , 문일식 Il Shik Moon

DOI: Vol.21(No.3) 289-296, 2005

Purpose of this research is to quantitatively and qualitatively investigate the blow down wastewater produced from Yeosu Industrial Complex. Approximately, 38,325,000 tons/year of wastewater is produced, processed and finally discharged. Six representative companies, namely, A, B, C, D, E, F were chosen for this study. Each company produce over 5,000 tons/day of wastewater. In total, 6,844 tons/day of blow down water is produced from these six companies, put together. However, companies A and C produce about 24% and 37% of blow down water, respectively. It was found that the blow down water had favorable qualities, except for its high conductivity, ranging from 230 to 1,700 μs/㎝. It was evident that, this water can be suitable for reuse, for industrial purposes, if a suitable treatment, for example, RO membrane process is adopted to remove high conductivity.

Industrial wastewater, Blow down water, Cooling tower water, Boiler water, Reuse