최승일 Suing Il Choi

DOI: Vol.11(No.3) 153-161, 1995

이현동 , 종궁공 宗宮功 , 이의신 Hyun Dong Lee , Isao Somia , Eui Sin Lee

DOI: Vol.11(No.3) 163-174, 1995

This study was conducted in order to elucidate basic conditions for the oxidation of ammonia-nitrogen with ozone in bromide containing water. The denitrification rates were observed under the batch and the continuous types at various concentrations of Br, initial pH and ozone dosages. The result showed that the oxidation reaction of ammonia-nitrogen with ozone was not occurred in the presence of BrO₃, but denitrification and nitrification took place in the presence of Br. This implies that OBr functioned as the oxidant for the oxidation of ammonia-nitrogen. The reaction rate of denitrification was quasi Zero-order with respect to dissolved nitrogen compound concentration and the reaction rate constant, K can be expressed in terms of ［Br］ and ［O₃］: K=0.023 ［O₃］·［1-10 ^(m [Br])］ The initial pH effect on denitrification rate was not significant in the range of pH 5.6∼10 but the removal rate was low at pH 3 presumably due to the retardation of OBr production under the low pH condition. Also with raising Br concentration, nitrification rate decreased but with raising initial pH, denitrification rate increased because ozone can react with NH₄ at fast rate. The denitrification kinetics obtained from batch experiment was used and applied to the continuous type process.

허인량 , 박상균 , 최규열 , 정의호 In Ryang Huh , Sang Gyun Park , Kyu Yol Choi , Ui Ho Jeong

DOI: Vol.11(No.3) 175-181, 1995

There are a number of recreational facilities and large scale cattle farms around upper region of Song Stream, and they have raised concerns about the possible pollution of the stream. This study evaluated the extent of pollution at two segments of the stream to provide water quality data for efficient pollution source control. Stream flows and water qualities for three other small streams that flow into the segment No.3 of the Song Stream were also analysed, and these data were used to estimate pollution loadings from each stream. The estimated production pollution loading to the Song Stream were 3,079㎏ for BOD, 1,691㎏ for total nitrogen, and 176㎏ for total phosphorus. Of the total loadings, wastes from the cattle farms accounted for 79.8% for BOD, 50.8% for T-N, and 89.1% for T-P.

김경섭 Kyung Sub Kim

DOI: Vol.11(No.3) 183-191, 1995

A one-dimensional eddy diffusion model is developed and applied to simulate the vertical temperature profiles in lakes. Eddy diffusivity which does not need lake-specific fitting parameter is applied. The heat exchanges at the water surface and the bottom are formulated by the energy balance and zero energy gradient. Application of this model which uses explicit finite difference method demonstrates that the model efficiently simulates water temperatures.

박배경 , 박석순 Bae Kyung Park , Seok Soon Park

DOI: Vol.11(No.3) 193-200, 1995

Statistical analyses of water qualities were performed to compare the land use impacts on the receiving streams of the watersheds located in the central part of the Korean peninsula. The data were obtained from the three hundred seventy three tributaries in the watersheds including the Lower Han River, the South Branch of the Han River, the North Branch of the Han River, the Kyungan Stream, the Anseong Stream, the East Coastal Streams, and the West Coastal Streams. Triplicate samples were collected at each sampling station depending upon the flow conditions(mid, low, and high flow) from March to July 1992. The data were statistically analyzed by the multiple linear regression method, where explanatory and response variables were each land used types and receiving water qualities. The water quality parameters included in the statistical analyses were 5-day biochemical oxygen demand, suspended solids, anionic surfactants. and conductivity. The areal ratios of three different land use types were used as explanatory variables: urban area, agricultural area, and forest area. Regression coefficients were estimated for each water quality and the significances of coefficient values were tested using the t-test. Linear relationship between explanatory variables and response variable was also tested by the F-test. From this study, it was noted that receiving water qualities were significantly impacted by an urban area in all tested watersheds. The high values of regression coefficients were computed for the Lower Han River, the South Branch of the Han River, and the West Coastal Streams in the most water qualities. It was also recognized that urban area in the South Branch of the Han River and forest area in the West Coastal Streams shown unusual high values of regression coefficients in most water qualities. The result indicated that the regression method presented in this paper would be useful in comparing stream water qualities for multiple watersheds with multiple land use types.

최용수 , 신응배 , 이영대 Yong Su Choi , Eung Bai Shin , Young Dae Lee

DOI: Vol.11(No.3) 201-210, 1995

Experimental study for the removal of organic and phosphorus in synthetic wastewater was conducted in a single reactor including anaerobic-anoxic-aerobic zone and clarifier. Attempts were made to delineate phosphorus removal mechanisms and to evaluate the removal efficiencies of organic and phosphorus with different internal recycle ratios, N/P ratios and various SRT conditions. The removal efficiencies of TOC, BOD and COD were observed to be higher than 95%, 90% and 90% respectively with aerobic recycle rates of 100% and 200%. It was recognized that the optimal operational condition for phosphorus removal was the aerobic internal recycle rate of 100% with the inlet fraction 0.2. The percent removal efficiencies were 92.1% for T-P and 90.1% for PO-4-P. While, large differences in the removal of phosphorus with N/P ratios were observed; at influent TKN/T-P of 2.5, 3.6 and 5.1, removal efficiencies for T-P were 88.7%, 67.6% and 55.9%, respectively. Those removal efficiencies decreased with the increase of N/P ratio in wastewater charged. In case of SRT, removal rates of 93.5% for T-P and 92.1% for PO₄-P were observed with the solid retention time of l0 days. These rates are higher than results in 5 days and 20 days of SRT. Thus high removal efficiencies for organic substances and phosphorus in wastewater were simultaneously obtained by a new biological process with a single reactor.

이태호 , 신훈길 , 김창원 , 한기백 Tae Ho Lee , Hun Gil Sin , Chang Won Kim , Ki Bak Han

DOI: Vol.11(No.3) 211-220, 1995

Mathematical models have been developed to understand and optimize the biological wastewater treatment process. In this research, SSP(Simulation of Single sludge Process) program, based on IAWQ model NO.1, was used to evaluate treating capacity of a pertrochemical wastewater treatment plant. The biokinetic and stoichiometric coefficients were calibrated and verified, and then the treatment capacity was estimated. Sensitivity analysis showed that the effluent COD concentration was greatly influenced by the parameters such as μ_H, K_S, and K_(dH) and MLVSS was affected by Y_H and K_(dH), while other parameters hardly had any effect. The calculated kinetic and stoichiomertric coefficients were μ_H, 9day¹, k,_COD 80㎎/ℓ, K_d 0.133 and Y_H 0.515 gCOD/gCOD. However, verification resulted relative error of 30%∼40% which was maybe due to different operating condition in 1991 and 1992. As a result of estimating the treatment capacity, the maximum allowable volumatric loading rate would be 1.35㎏/㎥·day based on MLVSS of 8,000㎎/ℓ. This means that the treating capacity of 1992 can be incereased up to 24%

우스순 , 방명렬 , 윤경애 , 박정희 , 김영진 , 최규열 , 정의호 Seung Soon Woo , Myong Ryul Bang , Kyong Ae Yoon , Chung Hee Park , Yong Jin Kim , Kyu Yol Choi , Ui Ho Jeong

DOI: Vol.11(No.3) 221-229, 1995

This research was conducted to evaluate the removal efficiency and the pollutant loading in AOD(Aerobic Digestion+Oxidation Ditch)plant, AAS(Aerobic Digestion+Activated Sludge)Plant, ANA(Anaerobic Digestion+Activated Sludge)plant and ACC(Aerdbic Digestion+Chemical Coagulant)plant for nightsoil treatments. The anual collection amount of nightsoil and septage in AOD, AAS, ANA and ACC treatment plants were 6,328.4, 7,418.3, 18,246.5 and 5,106.5 kl/year, and the ratio of nightsoil to septage of these were 12:1, 2:1, 1:1 and 3:1 respectively. The removal efficiency of BOD, SS, TKN and TP in ACC plant were 98.2, 98.4, 65.6 and 98.0% respectively, which was the highest removal efficiency of the four plants. The loading amount of BOD, SS, TKN and TP loaded into the river per the collected nightsoil in ACC treatment plant were 0.06, 0.08, 0.4 and 0.02㎏/㎥/day, and the average loading amount of the other three treatment plants were 0.74, 1.33, 1.20 and 0.27㎏/㎥/day respectively.

김범철 , 김은경 , 표동진 , 박호동 , 허우명 Bom Chul Kim , En Kyong Kim , Dong Jin Pyo , Ho Dong Park , Woo Myung Heo

DOI: Vol.11(No.3) 231-237, 1995

Cyanobacterial blooms in eutrophic lakes often produce algal toxins causing death of cattle, wild animals, and fish. Many lakes and reservoirs in Korea are eutrophic and suspected for toxic cyanobacterial blooms. Phytoplankton were collected in late summer at the surface of 5 middle-stream reservoirs(Soyang, Choongju, Daechong, Jangsong, Hapchon), one estuarine reservoir(Yongsan), and a coastal lagoon(Yonglang). Phytoplankton communities were examined and the occurrence of toxic bloom was examined with mouse bioassay. In all the study lakes cyanobacteria were dominant phytoplankton. Especially, the appearance of Microcystis aeruginosa in all the study lakes that is a well-known toxin-producer species implies the possibility of toxic water bloom. Dried cells were extracted in saline solution and injected to mouse intraperitoneally for the test of toxicity. Mouse bioassay showed lethal effect for L. Yonglang, L. Hapchon, L. Jangsong, and L. Yongsan. The content of two cyanobacterial hepatotoxins(microcystin-RR and microcystin-LR) that have been reported to be most common were analyzed with HPLC. Microcystin-RR was detected in L. Daechong, L. Choongju, and L. Soyang. And microcystin-LR which has higher toxcicity was detected in L. Hapchon, L. Jangsong, L. Yonglang, and L. Yongsan. The coincidence of the microcystin-LR occurrence and the lethal effect in bioassay imply that microcystin-LR exerted more critical toxicity. From this study it was found that toxic cyanobacterial bloom is common in Korean lakes that are used for water supply.

이동석 Dong Seok Rhee

DOI: Vol.11(No.3) 239-246, 1995

The Complex formation of the humic acid (isolated from ground water) with trivalent metal, americium, has been examined by absorption spectroscopy at varing pH-value, 6.0 to 3.0. In the study of the complexation, the Proton Exchange Capacity (PEC) of the humic acid was characterized. And the loading capacity of the humic acid for the metal ion was determined separately at each pH. The loading capacities were reduced with reducing pH. The description of the complexation of humic acid with metal was based on a model as simple as possible. Taking the loading capacity into account, the humate complexation constant is found to be independent of pH. The overall complexation constants at every pH value lie between 6.02 and 6.33 in 0.1 M NaClO₄.

김성석 , 이건호 , 정재연 , 김남성 , 김순래 , 김종철 , 최규열 , 정의호 Sung Seok Kim , Geon Ho Yi , Jae Yun Jeong , Nam Sung Kim , Soon Rae Kim , Chong Cheol Kim , Kyu Yol Choi , Eui Ho Jeong

DOI: Vol.11(No.3) 247-256, 1995

A survey to determine the characteristics of groundwater qualities in Kangwon-Do, which was divided 4 regions, was conducted from January to December in 1994. The results showed that the pesticides and chlorinated ethenes were not detected in the potable groundwater. But ca. 40% of the groundwaters were not satisfied the Korea Drinking Water Quality Standards because of the microbiological aspects, nitrates and Zinc, etc. The concentrations of pH, Zinc and consumption of KMnO₄ were not varied much, but the variation of the concentrations for chlorides and nitrates in each region were relatively high. Also the seasonal changes for the hardness and sulfates were within 10%, while the nitrates and chlorides were ranged from 15.5% to 18.0% in Chuncheon.