이윤 , 김상종 , 하영칠 , 홍순우 Youn Rhie , Sang Jong Kim , Yung Chil Hah , Soon Woo Hong

DOI: Vol.1(No.1) 1-8, 1985

홍순우 , 하영칠 , 안태석 Soon Woo Hong , Yung Chil Hah , Tae Seok Ahn

DOI: Vol.1(No.1) 9-17, 1985

In Jinhae bay, the physicochemical, biological and ecological surveys were carried out 65 times at six sites both in surface and bottom water from July 1976 to December 1982. Twenty one abiotic and biotic parameters were determined on each sample. These data were subjected to factor analysis to scrutinize the effects of environmental conditions on water quality and ecosystem. The phytoplankton blooming was the major factor of the variance of the water quality and ecosystem in Jinhae bay. Fresh water inflow was second factor at site 1 and 6, and it was third factor in site 3 and 5. The nitrogen inflow was also play an important role, which was second factor at site 2, 3, 4 and 5, and third factor at site 1. Beside above factors, the increasing of organic materials, waste water inflow, precipitation and recycling of nutrients, upwelling of sediment, nutrient salts and photosynthesis were also determined for the variation of water quality and ecosystem.

김범철 , 심재형 , 조규송 Bom Chul Kim , Jae Hyung Shim , Kyu Song Cho

DOI: Vol.1(No.1) 18-23, 1985

Scasonal and horizontal variations of chlorogphyll a concentration were surveyed in Lake Soyang, a long, narrow and deep artificial lake in a mountainous district. Pattern of seasonal variation at the dam site did not show regular blooms, but irregular blooms occurred through late spring to early autumn, and at the stream inlet sites a yearly regular bloom could be observed in late autumn. Chlorophyll a concentration varied greatly with the distance from the inflowing stream inlet. Though the concentration was in the range of oligotrophic level (5㎍/ℓ)at the dam site, peak value at the inlet sites far exceeded eutrophic level (up to more than 100㎍/ℓ). Such hi호 density of phytoplankton in the upstream area can be partly explained by the high phosphate concentration in the inflowing stream water. In addition phytoplankon aggregation may be attributed to a physical process Which could trap dinotlagellates coupled with their phototactic movement. These dinoflagelates are dominant species in the research lake throughout the warn season.

이상은 Sang Eun Lee

DOI: Vol.1(No.1) 24-31, 1985

During this research, the DO uptake rate data were used to evalulate the performance of activated sludge units with various aeration configuration. The following conclusions were derived from this study. A linear relationship exists between DO uptake rate and substrate removal rate. In the initial compartment of compartalized aeration basin configuration, substrate removal by nonoxidative mechanism, is significant. Therefore, the exogenous substrate is first adsorbed or converted to storage product in the initial stage of compartmentalized system and floc formers with higher adsorption and storage capacity can survive better in such system than filamentous microorganism. The proportion of substrate removal by the non-oxidative mechanism becomes larger as the relative size of initial compartment to the aeration basin becomes smaller. The selector system optimizes the separtation of the various removal mechanisms. While 90% of the applied substrate was removed in the selectors, only 15% of total oxgen demand was exerted during this stage, this indicates that most of exogenous substrate was removed by adsorption and/or converted to storage product in selector and substrate respiration and endogenous respiration take place in aeration basin. This separation selects floc formers rather than filamentous microorganisms and thus the system produces the sludges with good settling characteristics.

김기태 , 안유환 K . T . Kim , Y . H . Ahn

DOI: Vol.1(No.1) 32-42, 1985

In order to elucidate hydrological environment, air and water temperature, water transparency, dissolved oxygen and chemical oxygen demand were measured in a small pond Dansan located in Taegu City, Republic of Korea, from August 1983 to February 1984. Thermocline represent significant variation between summer stagnation and autumn circulation of water mass. For climatical and hydrological season, equation between waterdepth (Z) and number of delayed days (D) is the following: D=28.7 3√Z(m). Values of dissolved oxygen ranged from 10.8 to 13.3 ppm on surface, and from 0 to 4.0 ppm in bottom, which represents clear variations in proportion to depth. Values of chemical oxygen demand arc maximal in 3 m depth (September), and minimal in 6 m depth (February). Euphotic layer mainly linked to solar radiation does not generally extend to the bottom. Water mass of this pond permits only primary production to about 5 m depth.

정팔진 Paul Gene Chung

DOI: Vol.1(No.1) 43-53, 1985

This investigation were carried out to find the trophic level in an artificial lake to estimate the chlorophyll-a concentration on basis of limitting factor of water qualities data on influent of Spring, comparing with the actual those of Summer season, and judge the feasibility of developed models to the artificial lake. The results obtained are as follows. Summer mean values of the artificial lake of shinhoon showed that chlorophyll-a concentration was 69.2 ㎍/ℓ, Secchi depth, 1.625m and Hypolimnetic Oxygen Depletion Rate, 1,476 g/㎡/d. If inorganic carbon, total phosphorus, and total nitrogen of Spring are individually considered as a limihing factor, the predictive values of chlorophyll-a are 215 ㎍/ℓbased on Carbon, 231 ㎍/ℓbased on total phosphorus, and 874 ㎍/ℓbased on total nitrogen. According to these values, carbon might be a limitting factor of phytoplanktion growth in an artificial lake. When the phosphorus lading of Spring in the artificial lake was applied to Vollenweider-OECD model, the values at the best fit lines showed that chlorophyll-a was 20.4 ㎍/ℓ, Secchi depth, 1.505m, and Hypolimnetic Oxygen Depletion Rate, 0.775 g/㎡/d. In order to develop the prediction model of water quality for water bodies in Korea, it is needed to collect the broad and reliable data for a long time.

조광명 Kwang Myeung Cho

DOI: Vol.1(No.1) 54-61, 1985

To determine the pH range which permits acid or alkaline wastewaters be treated by biological processes without preneutralization, experiments were performed by feeding completely mixed activated sludge reactors with synthetic organic wastewaters, the pHs of which were adjusted with sulfuric acid or sodium hydroxide. Results of the research showed that wastewater treatment efficiencies deteriorated as the pHs of wastewaters became too acid or alkaline due to the bulking and poor settleability of microbial sludge, and that the pH at which sludge bulking initiates was affected by the F/M ratio in the reactors. Therefore, it is advised to reduce F/M ratio by increasing MLSS concentration or hydraulic detention time in reactors in order to alleviate the effect of wastewater pHs on sludge bulking. It was also found that the pH and alkalinity of treated effluent increased through biological treatment, and that microbial yield coefficient and endogenous respiration rate decreased as the influent becomes more acid or alkaline.

김동군 , 이문호 , 송준상 D . K . Kim , M . H . Lee , J . S . Song

DOI: Vol.1(No.1) 62-66, 1985

Cadmium removal by activated sludge was carried out at various treatment conditions to elucidate the bast condition for the treatment of wastewater containing high concentration of cadmium. Cadmium was removed by adsorption on the sludge surface. Cadmium removal was leveled off after 3.5 hours of treatment, and the amounts of removal was proportional to the sludge concentration. Cadmium removal rate was increased by increasing pH of treating mixture. Although cadmium removal rate was increased with temperature rise, amount of cadmium removed per unit amount of VSS was constant of 140-150 ㎎-Cd/g VSS. Cadmium removal capacity of activated sludge was not changed by storage of activated sludge at room temperature for 4days, by storage at room temperature with aeration or by storage at 4℃ without aeration.

이찬기 , 류재근 Chan Ki Lee , Jae Keun Ryu

DOI: Vol.1(No.1) 67-74, 1985

In recent year there has been considerable concern about waste discharges of chromium and cyanides to aquatic ecosystems. Chromium occurs in aqueous systems as both Cr (III) and Cr (VI). the Cr (VI) is of particular concern because this form has been demonstrated to be a public health hazard. The toxicity of cyanides to fish has long been recognized. Compounds containing the cyanides radical are frequently present in effluents of many industries, including electroplating plants, steel mills, petroleum refineries and gas works. The objective of this study is to remove the chromium and cyanides in the wastewater efficiently. In the experiment the amount of NaHSO₃ used for treatment were 2,4,6,10 and 20 ㎖ and the concentration of chromium was 100, 200, 300, 500 and 1000 ㎎/ℓwastewater. At that time efficiency was 99.1%-99.9% and the efficiency of pH 1.5 was better than pH 1, pH 2 and pH 3. The results of cyanides treatment was that concentration of residual CN^- ion was below 0.003 ㎎/ℓ, treated efficiency was 99.9%-99.98%, and in case of pH 9 was better than pH 11.