이현동 Hyun Dong Lee , 배철호 Chul Ho Bae

DOI: Vol.18(No.6) 569-576, 2002

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전석준 Seok Jun Jeon , 현경학 Kyoung Hak Hyun , 정경영 Gyoung Young Jung

DOI: Vol.18(No.6) 577-584, 2002

The purpose of this study was to develop an alternative coagulant supply device to replace a conventional chemical dosing system used in the chemical precipitation process for phosphorus removal, Bench-scale multi-stage anaerobic fixed bed reactors were packed with iron nuts and domestic wastewater was fed continuously to enhance microbially induced corrosion under anaerobic condition. Total iron concentrations in the effluent varied between 7.8mg/L- 13.0mg/L over the 90days of testing period ensuring sustained corrosion of iron in the reactors. The corrosion of iron in the anaerobic reactor was greatly influenced by sulfate reducing bacteria(SRB) as sulfate concentration was inversely proportional to total iron concentration from the first to the last reactor effluents, Besides the merits of iron as coagulants supply, favourable characteristics such as alkalinity production and minimal organic loss for sustained biological denitrification were identified, In case of introducing the anaerobic fixed bed reactor prior to secondary treatment system, it is required to operate the anaerobic reactor at the HRT of 67.5 minute or above in order to remove phosphorus from domestic wastewater.

김창운 Chang Woon Kim , 조광명 Kwang Myeung Cho

DOI: Vol.18(No.6) 585-594, 2002

Ths study was performed to investigate the nitrogen and phosphorus removal capability of the reactors packed with sulfur/seashell and slag, The results of the experiment using slag showed that the smaller the size of the slag particle, the better the alkali supply and the phosphorus removal capacities of the slag. When the influent PO_4^3--P concentration was maintained at 10 mg/L and the NO_3^--N concentration was increased, the denitrification efficiency of the reactors packed with sulfur/seashell and slag was above 90% up to the loading rate of 116 g NO_3^--N/m^3-day, but deteriorated to 57% at the loading rate of 170 g NO_3^--N/m^3-day. The effluent PO_4^3--P concentration of the slag-packed reactor was above 1.0 mg/L, but was below 1.0 mg/L when the effluent of the sulfur/seashell packed reactor was fed into the slag-packed reactor after filtration. The average SO_4^2- generation rate was 7.0 g SO_4^2-/g NO_3^--N removed, which was less than the theoretical value of 7.54 g SO_4^2-/g NO_3^--N, The pH and alkalinity of the final effluent was kept higher than the influent due to supplement of alkalinity by the seashell and slag.

이광현 Kwang Hyun Lee , 김종팔 Jong Pal Kim , 이종백 Jong Baek Lee

DOI: Vol.18(No.6) 595-604, 2002

The application of ceramic ultrafiltration membrane and reverse osmosis membrane using acrylic wastewater treated by photo-catalyst pretreatment and coagulant-filter-neutralization pretreatment processes was discussed with the variation of applied pressure and temperature. Turbidity were shown high removal efficiency in ceramic ultrafiltration membrane process using photo-catalyst pretreatment and coagulant-filter-neutralization pretreatment, It was shown that TDS was highly affected with the variation of applied pressure. Removal efficiency of COD with ceramic ultrafiltration membrane was better with the acrylic wastewater by coagulant-filter-neutralization pretreatment than acrylic wastewater by photo-catalyst pretreatment.

권중천 Joong Chun Kwon , 문서연 Seo Yeon Moon , 양창환 Chang Hwan Yang , 최경민 Kyung Min Choi

DOI: Vol.18(No.6) 605-612, 2002

In this study, a biofilter was applied to a municipal wastewater reuse system. It is an effective unit process in which the biological oxidation by the biofilm attached on the media and the filtration by the packed media happen simultaneously. First of all, the denitrification efficiency of this process was assessed according to the HRT, influent COD/N ratio, and media type. As a result, the effluent NO_3^--N concentration was less than 2 mg/L at the HRT 1∼3hr, and then denitrification efficiency ranged 74∼95 %. Without regard to the type of media used to pack biofilter, a maximum denitrification rate of about 164 g NO_3^--N/m^3-d was achieved with methanol, than the required COD/N ratio was close to 4.5 g COD/g NO_3^--N. And the biofilter was scaled up and operated for the treatment of the municipal wastewater passed through the biological advanced treatment. Under the filtration rate of 0.25∼0.5 m/hr, effluent SS concentration was less than 6 mg/L. If the filtration rate is increased, it have to increase that the media packed layer of the biofillter.

김홍태 Hong Tae Kim , 박창광 Chang Kwang Park , 신석우 Seok Woo Shin

DOI: Vol.18(No.6) 613-620, 2002

It is very important to determine the reaction time in the process which is used to intermittent aeration system. This study was performed to evaluate the applicability of ORP(Oxidation Reduction Potential) for determining the optimum reaction time in SBR. During the aerobic phase, "ammonia valley"^(5) was shown remarkably in ORP curve, and "nitrate valley" was also conspicuous in anoxic phase. But during anaerobic phase, there is no special valley in ORP curve. Therefore we have used ORP slope curve, which made it possible to find the end point of P-release. It has been concluded that ORP is a useful and reliable parameter to determine reaction time and that it is possible to optimize reaction time using ORP curve and ORP slope curve in SBR.

방승석 Seung Souk Bang , 정효준 Hyo June Jeong , 이홍근 Hong Keun Lee

DOI: Vol.18(No.6) 621-635, 2002

This study was carried out to select optimal sites of waste water treatment plant in a small watershed area as Boryeong-Hongseong located at south Chungcheong province. For the extraction of watershed from the study area, ArcView GIS 3.2 was used with HEC-GeoHMS 1.1 extension. Futhermore, Image Analyst, GeoMedia, and MicroStation were used for the data conversion. In order to compute selection factors, simple addictive weighting method and factor combination technique were used, Four possible sites were selected after considering geologic, hydrological, and pollutant loading etc, ChongsoMyeon was the most appropriate site among four possible sites. It had low elevation, low population density, and good accessibility. We confirm that GIS would be a good tool to analyze spatial data and to select optimal conditions for decision-making sites such as wastewater treatment plant in a small watershed area.

문병현 Byung Hyun Moon , 김상수 Sang Soo Kim , 이강춘 Gang Choon Lee

DOI: Vol.18(No.6) 637-645, 2002

When wastewater treatment is performed with the advanced biological wastewater process, the quality of effluent depended on the floc characteristics is affected by the fill time for influent. The aim of this study was to investigate how different fill time for sequence batch reactors (SBR) influences pollutants removal and characteristics of biological flocs. The biological flocs were characterized by size distribution and fractal dimension using Small Angle Laser Light Scattering (SALLS) method. SBR with short fill time shown higher removal efficiencies of COD, BOD, T-N and T-P. Larger floc size and fractal dimension were produced at SBR with short fill time. The short fill time produced the sludge with better settling properties and thickening, Alternating anaerobic and aerobic condition also affected the floc size. The floc size decreased under anaerobic phase, and floc size increased under aerobic phase. However, the fill time condition more affected the fractal dimension of floc.

박대원 Dae Won Pak , 김동건 Dong Kun Kim , 장원석 Won Seak Chang , 고창일 Chang Il Koh

DOI: Vol.18(No.6) 647-655, 2002

We performed the tests using two different mada(R1-bioball. R2-bioball) fixed biofilm reactors, investigated the efficiencies as pretreatment of drinking water, and identified the connecting possibilities of membrane treatment as posttreatment. As results of 100 days monitoring under different HRT (2, 4, 6 hr), organic compound removal of two reactors showed 38.5 % and 34.3 % in spite of increasing 8 to 10 times of loading rate, the color, turbidity, and chloropyll-a also showed higher removal 78.0 % to 94.9%. Therefore, the application of fixed biofilm is proved effective pretreatment process of removing color, turbidity, algae (chloropyll-a) as well as organic compounds. And also, as results of connecting possibility with membrane process (UF and NF). TOC and turbidity removals in UF system showed 45.4% (R1) and 40.2 % (R2); 98.5 % (R1) and 98.3% (R2), respectively, those in NF system showed 59.4% (R1) and 53.4 % (R2); 99.2 % (R1) and 99.1 %, respectively. In spite of conventional drinking water treatment system, combination of fixed biofilm and membrane system would be used to water purification system on pretreatment and posttreatment.

김종석 Jong Seok Kim , 염익태 Ick Tae Yeom , 조성우 Sung Woo Jo , 이석헌 Seock Heon Lee , 안규홍 Kyu Hong Ahn

DOI: Vol.18(No.6) 657-664, 2002

The main finding of this research was the fluorescence and light scattering properties of water, their relationship with corresponding NOx(NO_2+NO_3). Chlorophyll-a values and the correction for interference matter. The samples obtained from surface and domestic water. In experimental conditions, spectrum of NOx(NO_2+NO_3) detected at excitation/emission wavelength 220/220nm and Chlorophyll-a detected at 430/677nm. All spectrum were performed using in scan mode, scan speed 300nm/min, excited/detected spectrum band width 5nm, and xenon lamp(20kW) as light source. The correlation between NOx(NO_2+NO_3) and light scattering intensity values, and the Chlorophyll-a were high. Especially the NOx(NO_2+NO_3), the calculated values by multiple regression using predictor variables highly correlated to the observed values. The result investigates the possibility of using a scattering technique for application of rapidly real-time and on-line monitoring of NOx(NO_2+NO_3) and Chlorophyll-a values.

박주형 J. H. Park , 신응배 E. B. Shin , 김연권 Y. K. Kim , 홍재용 J. Y. Hong , 이의신 E. S. Lee

DOI: Vol.18(No.6) 665-674, 2002

In order to see the storage and reuse capability of microorganisms, the intracellular storage compounds were induced using glucose or acetate as a sole carbon source. For the intracellular storage compounds reused without the addition of extra substrate, the μ_max(d^-1) and K_m(mg COD utilized/mg active VSS/d) values were 2.1∼3.7, 2.8∼5 for glucose and 1.8∼2.2, 2.8∼3.4 for acetate, respectively. Reusable fraction of the intracellular storage compounds were observed 18.5∼26.1% and 45.8∼47.6% as initial COD concentration for glucose and acetate, respectively. Prediction of the COD fraction was made using the NUR measurement and it was found that an error of COD fractionation was generated in terms of COD fraction when using microorganisms from the advanced treatment process. This error was due to the intracellular storage period for microorganisms and the error in COD fraction was observed about 10 % in terms of Ss(readily biodegradable COD) concentration. The storage and reuse capability of microorganisms would use to control purpose of the advanced wastewater treatment process.

서인석 In Seok Seo , 김병군 Byung Goon Kim , 홍성택 Sung Taek Hong , 박철휘 Chul Hwi Park , 김도군 Do Gun Kim , 천상욱 Sang Ook Chun

DOI: Vol.18(No.6) 675-682, 2002

In this study. the effects of temperature, C/N ratio and C/P ratio on the nutrients removal efficiencies of an intermittent aeration activated sludge process(KSDeN^TM process) were investigated with a pilot plant fed with the grit chamber effluent of `J` MWWTP. The effluent TCOD_Cr, and TBOD_5 were less than 10 mg/L, although the influent concentrations of organics and nutrients showed wide fluctuations. T-N removal efficiency and nitrification efficiency increased with increasing temperature and C/N ratio. The results of this study showed that the performance of KSDeN^TM process was more sensitive to the variation of temperature than that of C/N ratio, However, T-N removal efficiency was more than 60% at 10℃, and more than 70% at low C/N ratio of 3.0. T-P removal efficiency was more than 80% at C/P ratio of 30 or above, and it was higher at relatively low temperature and high C/P ratio (TCOD_Cr/T-P ratio), It is considered that the competition on organic compounds between PAOs and denitrifiers resulted in lowering T-P removal by activating nitrifiers with increasing temperature.

이주동 Ju Dong Lee , 최상준 Sang June Choi , 김영훈 Young Hun Kim , 김한순 Han Soon Kim , 이정호 Jung Ho Lee

DOI: Vol.18(No.6) 683-692, 2002

Sinking behaviors of four freshwater diatoms were studied at various conditions (lightning, natural, killed and cultivated in laboratory). Water samples containing diatoms were collected from the Naktong River and the sinking rate of each species was measured by simple equation derived as function of the difference between the initial concentration and the final concentration in the lower part of the settling cylinder. Synedra acus, Aulacoseira sp., Stephanodiscus sp. and Asterionella Formosa were major phytoplanktonic diatoms in the river and each diatom species had constant sinking rate according to the fixed conditions. In natural condition (2000 Lux), the sinking rate was 10.80 mm hr^-1 for Synedra acus, 11.20 mm hr^-1 for Aulacoseira sp., 18.27 mm hr^-1 for Stephanodiscus sp. and Asterionella formosa had different values (11.66-15.70 mm hr^-1) in proportion to the cell numbers forming colony. Especially, in the dark condition, the sinking rates were faster than under the lighting condition, and moreover, killed diatom species sank faster than living ones. Ultimately, the sinking behavior of the species studied here applied to pilot test. The result of pilot tests indicated that the sinking characteristics of the diatoms had positive correlations with their removal efficiencies in drinking water treatment.

학회자료

DOI: Vol.18(No.6) 693-694, 2002

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