Seong Eun Chang , Young Joo Song , Young Heui Jung , Hee Sook Song , Kyung Hee Min

DOI: Vol.9(No.1) 1-6, 1993

조정우 , 박갑성 Chung Woo Cho , Kap Song Park

DOI: Vol.9(No.1) 7-11, 1993

Ames mutagenicity assay has been used to evaluate a small scale water treatment process which consists of bed filtration, sand filtration and chlorination process. Raw river water, bed filtered and sand filtered water demonstrated a negative mutagenic response with the Ames assay. Chlorinated water, however, induced mutagenicity suggesting chlorination produces increased levels of mutagenic activity in the treated water. Tester strains TA98 and TA100 which contain R-factor plasmid was found to be sensitive for the raw river water and chlorinated drinking water while TA1537 and TA1538 strains were not sensitivity for the studied waters.

이건호 , 박석순 Geon Ho Yi , Seok Soon Park

DOI: Vol.9(No.1) 12-22, 1993

A water quality modeling study was performed for the impounded stretches of the North Branch of the Han River. The constructed model was based on the Dynamic Hydraulic Model Version 4 (DYNHYD4) and the Enhanced Stream Quality Model (Qual 2E) which were developed by United States Environmental Protection Agency. The study area includes the Lake Uiam, two upstream branches(Soyang River from Soyang Dam and the North Branch of the Han River from Chuncheon Dam), and downstream to the Kangkyung Bridge, Kapyung. The study area was divided into 56 junctions and 59 channels for DYNHYD4 and 19 reaches for Qual 2E. Field data were obtained from two synoptic sampling survey during March and May 1991 for two consecutive days. Both models were calibrated to the March survey data and verified to the May survey data. The DYNHYD4 model was validated using the conductivity measurements as a conservative indicator. The hydraulic data simulated by the DYNHYD4 Model were used for the flow balance in the Qual 2E model. The water quality parameters simulated in the Qual 2E Model includes Dissolved Oxygen, 5-day Biochemical Oxygen Demand, Total Suspended Solids, Nitrogen Series, and Phosphorous Series and selected parameters were presented in this paper. The model study indicated that the combined approach of DYNHYD4 and Qual 2E was adequate to simulate the water qualities in the complicated system of the impounded stream. It was notable that the photosynthesis of periphyton and the sediment oxygen demand would cause discernible impact on dissolved oxygen level over entire system.

이병헌 , 김정숙 Byung Hun Lee , Jeong Sook Kim

DOI: Vol.9(No.1) 23-30, 1993

The main purpose of this study was to compare the suspened growth activated sludge with the fixed media activated sludge by evaluating organic removal efficiencies, nitrogen removal efficiencies, sludge production rates and oxygen requirements. The synthetic feed, containing glucose as the carbon source with nutrients and trace metals was used for influent. The suspended growth activated sludge reactor was made 2ℓ of aeration tank and 0.7ℓ of sedimentation tank. The fixed media activated sludge reactor was fulfilled with the plastic koch media and its volume was 2ℓ. The temperature and HRT were maintained at 20℃ and 11.5hrs, respectively. The organic removal efficiencies and nitrogen removal efficiencies of the fixed media activated sludge without settling tank were higher than that of the suspened growth activated sludge. The sludge productions of the fixed media activated sludge were smaller than that of the suspened growth activated sludge. But, the oxygen uptake rates the fixed media activated sludge were larger than that of the suspened growth activated sludge.

김운수 , 차시환 , 김용욱 Woon Soo Kim , Si Hwan Cha , Yong Wook Kim

DOI: Vol.9(No.1) 31-40, 1993

The purpose of this study is to investigate into the electrolytic treatment of polyvinyl alcohol wastewater. In order to remove PVA from wastewater by electrolytic treatment. Fe electrode was used as a soluble electrode for this study. The results are summarized as follows : 1. PVA was removed nearly to 100% as the value of ampere hour concentration was more than 0.5 Ahr/ℓ. 2. Regardless of the initial pH of wastewater, the pH of wastewater after electrolytic treatment was among 10 and 11. So, it is necessary to neutralize the treated water. 3. PVA was removed quickly as the current density was rised, the electrode distance was approached, NaCl was added and the initial pH of wastewater was above 7.

송교욱 , 박혜영 , 박청길 Kyo Ook Song , Hae Young Park , Chung Kil Park

DOI: Vol.9(No.1) 41-53, 1993

The water quality criteria of the Nakdong river is over third grade and trophic state in the area indicate over eutrophic state. Thus this study was conducted to analyze the distribution characteristics of algae and nutrients, and then to explore the interrelationships among them focusing upon the eutrophication in the Nakdong river. The intensive surveys which cover a 163.5㎞ section of the river from Waekwan downstream to Mulgum were conducted during May, June and August, 1991. The results of this study were as follows; 1. Nutrients and Chl.a concentration were estimated 0.04-4.88㎎/ℓ in ammonia nitrogen, 0.002 0.10㎎/ℓ in phosphate and 13.80-126.01㎎/㎥ in Chl.a during the same period. 2. From the Kumho river ammonia nitrogen and phosphate were inputted 40-70 times and 100-500 times higher than main river, respectively. In the waste loads, the Kumho river was the main source of the ammonia nitrogen and phosphate loads and estimated as 90% or more. 3. At Koryong the concentration of ammonia nitrogen and phosphate extended to maximum peak and as downstream flow their concentration was declined, while the concentration of Chl.a was increased. Maximum Chl. a concentration in this period was observed in June, and trophic state was eutrophic with the range of 36.19-126.01㎎/㎥. The revised Carlson`s trophic state index was 53.24-85.01. 4. Maximum specific growth rate(μ_(max)) was 1.07-3.14/day, and half-saturation constants of ammonia nitrogen and phosphate were 0.07-0.41, 0.03-0.12㎎/ℓ, respectively.

송교욱 , 안욱성 , 박청길 Kyo Ook Song , Ook Sung Ahn , Chung Kil Park

DOI: Vol.9(No.1) 54-66, 1993

The Nakdong river that was already over third grade in water quality criteria as BOD. The trophic state was over entrophic and the state of Do level was supersaturation inspite of high organic loads from the each tributary. It was the result of abnormal algal bloom according to the influent of each tributary which had high nutrient concentration. In all stations except Koryong, DO saturation level showed 114.4-160.9%. The model input parameters obtained by laboratory experiment were 0.11-0.49/d in deoxygenation rate(k-1) and 0.31-0.84g/㎡d in sediment oxygen demand(SOD). DO balance was conducted using the enhanced stream quality model(Qual 2E) which was developed by U. S. EPA. The Qual 2E model includes internal sources and sinks of oxygen. The major sources of oxygen, in addition to atmospheric reaeration, are the oxygen produced by photosynthesis and the oxygen contained in the incoming flow. The sinks of DO includes biochemical oxidation of carbonaceous and nitrogenous organic matter, benthic oxygen demand and the oxygen utilized by respiration. Based on the field data, the widely used Qual 2E model was calibrated and verified and then used to DO balance. The calibrated and verified results were in good agreement with measured value within relative error of 17%. In the result of DO balance, the major sources of DO were photosynthetic production and contribution rates of June and August were 71.47 and 48.02%, respectively. The major sinks of DO were biochemical oxidation of carbonaceous organic matter and the rates were 51.54 and 47.67%, respectively.

김원만 , 옥삼복 Won Man Kim , Sam Bok Ok

DOI: Vol.9(No.1) 67-73, 1993

In this study, it is necessary to consider the established conditions such as water supply capacity, diameter and types of pipeline, the lenghth of pipeline and various assumption in order to decide the low water level of the economical elevation of distribution reservoir by using water tap distribution. However, as these assumed conditions could be changed considerably according to the regional circumstances, investigating distribution ratio of water tap in each elevation in the distribution reservoir installation area could calculate a general formula in order to obtain the best low water level of the distribution reservoir installation elevation. Therefore, if we investigate the distribution of a water tap in the distribution reservoir installation area 30m(above sea level) to the highest by every l0m by using this general formula it is possible to find out applicable and appropriate low water level of the best installation elevation of the reservoir. Let He(m) be the most economical installation elevation of distribution reservoir in the same distribution sector, R_(W1)(%) be the largest distribution ratio of water tap in the elevation classified by every l0m, R_(W2)(%) be the distribution ratio of water tap in l0m higher than that of R_(W1). Following formula was calculated by analyzing the relationship between He, R_(W1)-R_(W2). He=7,692/(R_(W1)- R_(W2))+84