김원만 , 김홍석 Won Man Kim , Hong Seog Kim

DOI: Vol.5(No.1) 1001-1013, 1989

The objective of this study was improvement of removal efficiency in rectangular sedimentation basin. By revealing the relation between the water temperature and the water flow in the sedimentation basin, when flow rate and sedimentation basin volume are constant, the efficiency of sedimentation basin is preportional to the real retention time in basin. The real retention time by installing diffuser walls and locating overflow weir was investigated by dye-flow and effluent dye-concentration. Density flow could be controlled by diffuser walls. In case of installing diffuser walls to every overflow weir of four piece in equal space arranging, the removal efficiency was improved by placing the first weir from the 60% position flow direction.

박영규 , 이철희 , 황태구 Yung Kyu Park , Chul Hee Lee , Tae Gu Hwang

DOI: Vol.5(No.1) 1014-1019, 1989

Activated sludge-ozone treatability of tar wastewater and tar wastewater containing herbicide alachlor was studied. The microbial yield coefficients of activated sludge process for the tar wastewater increased with decreasing feed wastewater strength. However, the yield coefficient decreased for the alachlor wastewater. For the ozone oxidation of activated sludge effluent, COD removal efficiencies were 41% and 36% for the tar and alachlor wastewater, respectively, at O₃/COD ratio of 3.

이헌모 , 정병곤 , 양병수 Heun Mo Lee , Byung Gon Jeong , Byung Soo Yang

DOI: Vol.5(No.1) 1020-1029, 1989

This study was conducted to evaluate the treatment efficiency of synthetic wastewater by using both deep shaft activated sludge process and conventional activated sludge process without cellular recycle. Some results from this study were summarized as follows; Oxygen transfer efficiency in deep shaft aeration system can be changed in accordance with the depth of the deep shaft. However optimum superficial gas velocity seems to be less than 48.8 m/hr in superficial liquid velocity of 1,380m/hr when considering the power required for recycling mixed-liquid. The deep shaft unit performs better substrate removal efficiency than the activated sludge process in the range of hydraulic detention time from 0.8 days to 1.84 days. In case of the deep shaft unit, the values of the kinetic constant, Y, Kd, k and Ks were found to be 0.358, 0.227/day, 13.33/day and 333.0 ㎎/ℓ, respectively and the kinetics at the activated sludge process were 0.505, 0.137/day, 5.560/day and 285.8 ㎎/ℓ, respectively. Solid-liquid separation just with air dissolved at the hydraulic pressure at the bottom of the deep shaft tube could be done so well, and additional air dissolution seemed to be not required for this purpose.

안태석 , 조규송 Tae Seok Ahn , Kyu Song Cho

DOI: Vol.5(No.1) 1030-1034, 1989

The bacterial distribution and activities were studied in Lake Paldang from September, 1987 to June, 1988. According to the total bacterial nμMber, 9.3×10^5∼31.5×10^5 cells/㎖, the trophic state of Lake Paldang is meso-eutrophic state. By the kinetics of alkaline phosphatase, the values of V_(max) revealed the variation from 0.35∼3.45 μM/ℓ/hr, that of Kt + Sn revealed 0.39∼4.13 μM/ℓ. The organic degradation rates of organic phosphate were 7.8-100%/hr, and acetate uptake rates were 0.4-6.5%/hr. The bacterial density and activities showed higher values at inlet region of South Han River than that of North Han River.

홍기훈 , 조성록 , 박선규 Gi Hoon Hong , Sung Lok Cho , Sung Qyu Park

DOI: Vol.5(No.1) 1035-1046, 1989

이동수 , 김경태 , 홍기훈 , 이수형 D . S . Lee , K . T . Kim , G . H . Hong , S . H . Lee

DOI: Vol.5(No.1) 1047-1056, 1989

Concentrations of six environmentally important heavy metals (Cd, Cu, Fe, Mn, Pb and Zn) were determined at 14 sites in the Han River and its tributaries. Water samples were taken monthly from April to November, 1987, using a standard clean-sampling technique, acidified with 4 ㎖ of 6N HCl per liter of water, and then stored in acid-leached polyethylene bottles. In the laboratory, acid-soluble metals were determined by graphite furnace atomic absorption spectrometry after fifty-fold preconcentration by Freon-APDC extraction. All sample manupulations were carried out in a class-100 laminar-flow bench to minimize possible metal contamination. All metal concentrations increased rapidly from upstream to downstream probably due to the increased anthropogenic input: Cd, Cu, Mn and Fe increased ten-fold and Pb and Zn twenty-fold. Despite the elevated concentrations in the downstream, they are still significantly lower than those of the Korean water quality standards. It appeared that there were no measurable contaminations in the upstream above Soyang Dam, where metal levels were comparable to those of Amazon and Yantze Rivers. Metal concentrations in the Han River in this study are much lower than some of the previously reported ones and the previous high values may be attributed to some analytical artifacts including analytical errors rather than the actual reduction in concentrations due to water quality improvement.

정용 , 신동천 , 장재연 , 이보영 , 조성준 Yong Chung , Dong Chun Shin , Jae Yeon Jang , Bo Young Lee , Seong Joon Jo

DOI: Vol.5(No.1) 1057-1069, 1989

Besides of the legal water quality indices such as pH, NH₃-N, NO₂-N, Coliform groups and etc., the unregulated pollutants which is so called at $quot;microorganic chemicals$quot; or $quot;microorganic pollutants$quot; have been issued as being much increased to use and polluted in drinking water recently. They have been identified as one cause of modern diseases in toxicologically as well as epidemiologically This study was performed to identify the concentration as well as the kind of microorganic pollutants in drinking water and to provide the basic data for health risk assessment. The water samples were collected at three water supply stations for the quality of raw and treated water and six points of tap water in Seoul municipal areas during July and November in 1987. 10 kinds of the volatile organic pollutants such as vinyl chloride, carbon tetrachloride, trihalomethanes (THMs) and etc. were determined by purge trap method using gas chromatography. 19 kinds of polynuclear aromatic hydrocarbons (PAHs) such as benzo (a) pyrene, phenathren and etc. were processed by XAD-2 resin adsorption, liquid-liquid extraction and TLC separation, and determined by gas chromatography. The results of analysis were as follows; 1. THMs in treated and tap water were major pollutants among volatile organic pollutants detected. The highest concentration of chloroform was 13.45 ㎍/ℓ in tap water. 2. Carbon tetrachloride, vinyl chloride, 1,1-dichloroethane, 1,2-dichloroethane, trichloroethene, tetrachloroethene, benzene were not detected. 3. The total mean concentrations of PAHs were 188.93 ng/ℓ, 177.6 ng/ℓ, 148.12 ng/ℓ in the raw, treated and tap water, respectively. 4. The mean concentrations of phenathren were 77.49 ng/ℓ of the raw water, 55.08 ng/ℓ of the treated water and 46.32 ng/ℓ of the tap water, respectively. Phenanthren was polluted in the highest level of PAHs in the water samples. 5. Benzo (a) pyrene detected in tap water was the mean concentration 5.7 ng/ℓ which, less than WHO drinking water quality standards, 10 ng/ℓ. 6. The halogenated pesticide was as low as below the range of dection in the gas chromatography. With the above results, as microorganic chemicals being polluted, drinking water quality should be evaluated on the hazard and the risk. According to the risk assessment of benzo (a) pyrene and chloroform, the Seoulian drinking the water analyzed would be exposured to the risk occurrence about 200 additional case of cancer in a population of 10 million in a life time. Futher more researches of micro organic pollutants should be needed in the individual and population risk as well as be regulated legally.

구자공 , 권혁 Ja Kong Koo , Hyuk Kweon

DOI: Vol.5(No.1) 1070-1077, 1989

A vertically one dimensional segment model (DATPUS: Distribution and Transport of Pollutant in Unsaturated Soil) was developed for the prediction of equilibrium distribution and transport of pollutants in unsaturated soil zone during the water infiltration and drainage. The change of water content in soil profile was estimated using the method of characteristic on the kinematic unsaturated flow equation, and this was utilized for the estimation of mobile phase movement of soil water and soil air between segments and through boundaries of the atmosphere and the aquifer. The developed model of pollutant equilibrium distribution among soil grain (immobile phase), soil water, and soil air that can accommodate the effects of soil water content and temperature change was combined with the continuity equation at each segment through time steps. The nonbiodegradable, volatile, and toxic solvents of dichloromethane (DCM) and 1,1,1-trichloroethane (TCE) as a representive priority organic pollutant, were studied experimentally and simulated in sandy soil and silt-clay mixture at temperatures of 4, 20, and 40℃. The quantitive result showed that much severe soil pollution occurs at lower temperatures, deeper DCM plume is developed in unsaturated soil than TCE, and thousand times higher DCM flux is penetrated into groundwater as a pollution potential.