최충길 , 황영진 , 위인선 Chung Gil Choi , Young Jin Hwang , In Sun Wui

DOI: Vol.8(No.3) 135-140, 1992

Acute toxicities of five heavy metal ions on fertilzed eggs of killifish(Oryzias latipes) were measured in terms of median lethal concentration(LC50) and toxicity curve. The LC50 of 24, 48 and 96 hours were 24.00, 19,80 and 19.80 ㎎/ℓ for nickel; 8.30, 6.30 and 4.5㎎/ℓ mercury ; 6.75, 4.20 and 3.50 ㎎/ℓ for cadmium ; 0.68, 0.56 and 0.56 ㎎/ℓ for zinc ; 0.067, 0.065 and 0.065㎎/ℓ for copper respectively. The toxicity curves derived by polotting LC 50 values against the period of exposure, and the results indicate that effect of copper was most toxic followed by zinc, cadmium and mercury, and the effect of nickel was the least.

윤양호 Yang Ho Yoon

DOI: Vol.8(No.3) 141-149, 1992

Detailed analysis on the relationship between environmental conditions and phytoplankton growth was carried out the Kamak Bay, Southern Korea from January to November in 1991. Physico-chemical factors (temperature, salinity, sigma-t, dissolved inorganic nutrients such as ammonia, nitrite, nitrate, phosphate and silicate, N/P ratio) were collected 3 times a week as well as biological factors (chlorophyll a, phytoplankton species composition and cell number). The principal component analysis(PCA) proved that high density of phytoplankton biomass occurred under the condition of high temperature(=low salinity) and high concentration of dissolved inorganic nutrients. As the results of multiple regression analysis(MRA) of biological factors on physico-chemical factors as explanatory variable, phytoplankton growth was found to be controlled by some specific factor such as DIN (dissolved inorganic Nitrogen, but dinoflafellates(=phytoflageilates) growth by DIP (dissolved inorganic phosphorus) in warm seasons.

박혜경 , 천세억 , 박승익 , 이문호 , 류재근 Hae Kyung Park , Se Uk Cheon , Seung Ik Park , Mun Ho Lee , Jae Keun Ryu

DOI: Vol.8(No.3) 150-158, 1992

The distribution, the dominant species and the seasonal succession patterns of phytoplankton communities in lake Soyang, lake Daecheong, lake Chungju were investigated. Following facts have been clarified through the investigation. ○ Seasonal succession patterns of phytoplankton in lake Soyang and lake Daecheong showed strong seasonality. In lake Soyang, diatoms (mainly Asterionella spp.) were abundant in winter and early spring, this diatoms were replaced by dinoflagellates(Peridinium spp.) in late spring and blue-green algae(Anabaena spp.) succeeded the dinoflagellates in summer, the winter diatoms recurred in autumn. ○ In lake Daecheong, diatoms(mainly Melosira spp.) were dominant throughout the year except summer and early autumn. In summer and early autumn, blue-green algae especially Microcystis spp. dominated and formed the algal bloom. ○ In lake Chungju, diatoms were dominant throughout the year and the blue-green algal bloom was not occurred in summer.

박혜경 , 이문호 , 류재근 Hae Kyung Park , Mun Ho Lee , Jae Keun Ryu

DOI: Vol.8(No.3) 159-166, 1992

Algal Growth Potential spike tests for Paldang reservoir, lake Soyang, lake Chungju, lake Daecheong were carried out in order to identify algal growth limiting constituents, determine biological availability of algal growth limiting nutrients, and quantify the biological response to changes in concentrations of algal growth limiting constituents. Lake Chungju, South Han river and North Han river of Paldang reservoir were identified as extremely phosphorus-limited waters for algal growth. In lake Daecheong and lake Soyang, the primary limiting nutrient is phosphorus and when 0.050 ㎎P/ℓ is added limiting nutrient changed to nitrogen. Among the tested lakes, Kyungan river and Daecheong lake waters supported much increases in biomass up to 0.734 and 0.640㎎ dry weight of Selenastrum capricornutum/ℓ respectively due to the each ㎍ P/ℓ addition if other constituents are in excess.

박영규 , 이철희 , 김우항 Yung Kyu Park , Chul Hee Lee , Woo Hang Kim

DOI: Vol.8(No.3) 167-172, 1992

This study was conducted to evaluate the feasibility of dye industrial waste water treatment by oxygen activated sludge process in batch test. The treatment efficiencies of air activated sludge process and oxygen activated sludge process were compared in continuous bench-scale test. The treated effluent by oxygen activated sludge process was coagulated with alum. A six hour reaction time was required to reduce DOC from 748㎎/ℓ to 143㎎/1 with a MLSS concentration of 1660㎎/1 in oxygen activated sludge process, but total organic carbon particle(TOCp) increased 1.4 times after oxygen treatment. 95% and 93% of BOD were removed by oxygen activated sludge process that was operated in the F/M range of 0.44 to 1.12 and by air activated sludge process that was operated in the F/M range of 0.28 to 0.64, respectively. The oxygen process is capable to handle BOD loading 1.9 times greater than the air process. Also, the oxygen process was less sensitive to BOD loading and F/M ratio variation than the air process. The effluent of oxygen activated sludge process in the range 0.8-1.6(㎏ COD_(Mn)/㎥.day) was treated with 400㎎/ℓ of alum. It was observed that the combination of oxygen activated sludge process and alum coagulation resulted in effluent which contained below 100㎎/1 of COD-Mn.

임연택 , 윤조희 , 서정범 , 유순주 , 류덕희 , 홍정선 , 서윤수 Y . T . Rim , C . H . Yoon , J . B . Seo , S . J . Yu , D . H . Rhew , J . S . Hong , Y . S . Suh

DOI: Vol.8(No.3) 173-180, 1992

For a practical application of technologies for treating the polluted stream water, the Changneung Stream water at Koyang-Kun, Kyungki province was treated by using the Gravel Contact Oxidation Processes with the aerated and the non-aerated types as on-site facilities for one year. The results are as follows: 1. In the BOD concentration of the influent into facilities, annual average was 36.3㎎/ℓ. And monthly averages were the lowest as 6.6㎎/ℓ in Aug. and the highest as 40.2㎎/ℓ in Aug. In case of TKN, monthly concentrations were 3.2 ㎎/ℓ in Aug. and 13.3㎎/ℓ in Jun., which was caused by the difference of outflowing amount from paddy fields. 2. Annual BOD concentrations of effluents from the aerated and the non-aerated types were 15.6㎎/ℓ and 25.6㎎/ℓ, respectively and treatment efficiency was increased by the aeration. In the non-aerated type, average influent BOD concentration from Nov. to Feb. higher than 30㎎/ℓ was 61.1㎎/ℓ and effluent was 46.3㎎/ℓ but average influent BOD from Mar. to Oct. lower than 30㎎/ℓ was 18.5㎎/ℓ and effluent was 10.7㎎/ℓ. So it was essential to be aerated in the facility by judging from these efficiencies when the stream water over 30㎎BOD/ℓ was treated. 3. Annual influent suspended solid(SS) was 24.1㎎/ℓ and effluents were 6.4㎎/ℓ in the aerated type and 9.2㎎/ℓ in the non-aerated. It was essential to establish the facility for eliminating sludge which was generated in the gravel layer and inflowed from the stream, to upkeep the treatment efficiency of this facility. 4. In the case of TKN and T P, influent was 8.48㎎/ℓ and 1.10㎎/ℓ and effluent from the aerated and the non-aerated was 6.85㎎/ℓ, 0.86㎎/ℓ and 8.79㎎/ℓ, 0.99㎎/ℓ, respectively.

이승목 Seung Mok Lee

DOI: Vol.8(No.3) 181-187, 1992

A non-linear stochastic model is presented to describe the solute concentration profile over time in a batch process. The Langmuir-type non-linear isotherm was incorporated with the model to deal with adsorption. Model parameters were easily estimated by conducting batch experiments. The major advantage of this model is that the model calculations are simple unlike deterministic models which usually require the solution of partial differential equations. The model presented can be used satisfactorily in predicting rate curves for adsorption of trichloroethylene (TCE) on granular activated carbon (GAC) in batch reactor.

최의소 , 박미경 , 박후원 , 이호식 Eui So Choi , Mi Kyung Park , Hoo Won Park , Ho Sik Lee

DOI: Vol.8(No.3) 188-194, 1992

This study was conducted to estimate and characterize the nutrient generation rates from domestic water use. The generation rates per capita per day were 8.9 gr T-N and 1.7 gr T-P of which 85% was contributed by nightsoil. It was estimated that the amount of nutrient reached to a municipal plant served by separate sewer system was 5.4 gr T-N/ Capita/d and 0.74 gr T P/Capita/d which were respectively 62% and 44.5% of the amount measured from sources. The proposed nutrient concentrations at municipal plants were 15㎎ T N/ℓ and 3.5 ㎎ T-P/ℓ with combined sewer system, and 27 ㎎T-P/ℓ and 3.8 ㎎ T P/ℓ with separate sewer system.