• Journal of Environmental Science International
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• v.18 no.2
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• pp.239-244
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• 2009

In this study, to stabilize the heavy metal in the contaminated soils, the column leaching test based on rainfall and pH value was performed by using coal mine drainage sludge(CMDS): which was generated during electrical purification of abandoned coal mine wastewater. Four types of testing column were used in this study. That were the CMDS and the heavy metal contaminated soils well mixed in 0 wt%, 1 wt%, 3 wt% and 3 wt% layered column. According to the investigation, when the influent pH was $5.5{\sim}6.2$, there were no heavy metal elution at all conditions, and when the influent pH was $3{\sim}3.3$, the order of Cu, Zn, Pb, Cr elution concentration was 3 wt% M(mixed)<3 wt% S(separation)<1 wt% M<0 wt% and the average elution concentration was quite low, the value was 0.005 mg/L. Therefore, CMDS can used as new stabilizer of the heavy metal in the contaminated soils.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.1 no.1
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• pp.56-61
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• 2001

Activated sludge processes are broadly used in the biological wastewater treatment processes. The activated sludge processes are complex systems because of the many factors such as the variation of influent flowrate and ingredients, the complexity of biological reactions, and the various operation conditions. The main motivation o this research is to develop an intelligent control strategy for activated sludge process (ASP). ASP is a complex and nonlinear dynamic system owing to the characteristic of wastewater, the change in influent flowrate, weather conditions, and so on. The mathematical model of ASP also includes the uncertainty which is a ignored or unconsidered factor from process designers. The ASP model based on Matlabⓡ/Simulinkⓡ is developed in this paper. And the model performance is examined by IWA (International Water Association) and COST (European Cooperation in the filed of Scientific and Technical Research) data. The model tests derive steady-state results of 14 days. In this paper, fuzzy logic control approach is applied to handle DO concentrations. The fuzzy logic controller includes two inputs and one output to adjust air flowrate. The objective function for the optimization, in the implemented evolutionary strategy, is formed with focusing on improving the effluent quality and reducing the operating cost.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.4
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• pp.387-394
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• 2010

The influent COD of municipal wastewater has been divided into 4 fractions; readily soluble biodegradable, slowly particulate biodegradable, soluble and particulate unbiodegradable COD. The mathematical modeling of biological wastewater treatment processes and the design and operation of nutrient removal plants require a reliable and accurate estimate of the composition of influent wastewater COD. COD utilization rate is proportional to the oxygen uptake rate(OUR), so a batch biodegradation test with OUR measurement has been effectively used for the determination of COD fractionation. But the mathematical model of COD utilization and heterotrophs synthesis is essential to interpret the OUR measurement. Mamais method is another method for determining readily biodegradable soluble COD. Like the OUR test method, batch biodegradation test is necessary but it does not require mathematical model. These two methods for determining COD fractionation are introduced here in detail. Experimental results showed that COD composition by Mamais method is not different to that by OUR test method so, either of them can be used.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.4
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• pp.497-502
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• 2012

Anaerobic Digestion Process is evaluated as efficient wastewater treatment process with the removal of high concentrations of organic waste and production of biogas. This study was performed using hybrid anaerobic hybrid reactor (AHR) which consists of anaerobic sludge blanket (UASB) and biofilm-coated filter media was applied for Palm Oil Mill Effluent (POME) for 80 days to know optimum removal efficiency and production of biogas by comparing each part which divided changing Organic Loading Rate (OLR). As a result of this study, the removal efficiency was 90.4 % when the organic loading rate of influent was 15 kg COD/$m^3$/day. Since organic loading rate was up to 20 kg COD/$m^3$/day, the removal rate declined 80.7%. Over loading of influent caused sludge expansion and overproduction of microorganism. Amount of biogas was collected 82.3 L/day and pH was remained 6.9 constantly with balance of alkalinity.

• Journal of Environmental Health Sciences
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• v.43 no.6
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• pp.525-531
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• 2017

Objectives: The purpose of this experiment is to better understand the nitrogen and phosphorus removal ratio according to operating conditions in an iron electrolysis system consisting of an anoxic basin, aerobic basin, and iron precipitation apparatus. Methods: Iron electrolysis consists of an iron precipitation reactor composed of iron plates in oxic and anoxic basins. We studied the interrelation coefficient between T-N and T-P removal rates and F/M ratio, and the C/N ratio and BOD removal rate. Results: The F/M ratio and the T-N and T-P removal rate per unit area have interrelation coefficients of 0.362 and 0.603, respectively. The removal rate per MLVSS and the T-N and T-P removal rate per unit area have respective interrelation coefficients of 0.49 and 0.59. Conclusions: The removal rate of T-N and T-P increased with the increasing F/M ratio in the influent, and they also linearly increased in proportion to the C/N ratio of influent and BOD removal rate of the reactor.

• Journal of Environmental Science International
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• v.19 no.9
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• pp.1119-1127
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• 2010

The behavior of copper throughout the whole process of wastewater treatment plant that uses the activated sludge process to treat the wastewater of petrochemical industry that contains low concentration of copper was investigated. Total inflow rate of wastewater that flows into the aeration tank was $697\;m^3$/day with 0.369 mg/L of copper concentration, that is, total copper influx was 257.2 g/day. The ranges of copper concentrations of the influent to the aeration tank and effluent from the one were 0.315 ~ 0.398 mg/L and 0.159 ~ 0.192 mg/L, respectively. The average removal rate of copper in the aeration tank was 50.8 %. The bioconcentration factor (BCF) of copper by microbes in the aeration tank was 3,320. The accumulated removal rate of copper throughout the activated sludge process was 71.3%, showing a high removal ratio by physical and chemical reactions in addition to biosorption by microbes. The concentration of copper in the solid dehydrated by filter press ranged from 74.8 mg/kg to 77.2 mg/kg and the concentration of copper by elution test of waste was 2.690 ~ 2.920 mg/L. It was judged that the copper concentration in dehydrated solid by bioconcentration could be managed with the control of that in the influent.

• KSBB Journal
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• v.7 no.3
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• pp.235-245
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• 1992

A number of experiments to treat wastewater of a dye plant were conducted to investigate the basic design parameters and effluent characteristics for aerobic fixed biofilm reactor upon the variation of organic loading rate. The media used for this study were SARAN 4000 D with specific surface area $153m^2/m^3$, and 1000 D with specific surface area $307m^2/m^3$. The influent COD concentration ranged from 1250 to 4080 mg/L. Substrate removal and variation of biomass concentration were observed. At the beginning, the effluent quality was poor but improved as the time passed. However the effluent quality became seriously deteriorated when the media clogged. At influent COD of 1250mg/L, the effluent COD varied little, even if the organic loading rate increased from 0.63 to 2.5kg COD/$m^3$/day. It was also noted that the design parameters for activated sludge process could be applied to an aerobic fixed biofilm process under the experimental conditions.

• Journal of Microbiology
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• v.38 no.1
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• pp.36-39
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• 2000

Toxic hexavalent chromium, Cr(VI), was reduced to a less toxic trivalent chromium form by E. coli ATCC 33456. The suitable electron donor for Cr(VI) reduction was glucose. E. coli ATCC 33456 was more resistant to metal cations than other reported Cr(VI) reducing microorganisms. Cell growth was inhibited by the presence of Cr(VI) in a liquid medium and Cr(VI) reduction accompanied cell growth. With a hydraulic retention time of 20 h, Cr(VI) reducing efficiency was 100% to 84% when Cr(VI) concentration in the influent was in the range of 10 to 40 mg L$\^$-1/. Specific rate of Cr(VI) reduction was 2.41 mg Cr(VI) g DCW$\^$-1/ h$\^$-1/ when 40 mg L$\^$-1/ of Cr(VI) influent was used. This result suggested the potential application of E. coli ATCC 33456 for the detoxification of Cr(VI) in Cr(VI) contaminated wastewater.

• KSBB Journal
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• v.4 no.3
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• pp.253-258
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• 1989

It was investigated that the influent sugar concentration and the dilution rate have an influence on the ethanol fermentation characteristics at steady state in a chemostat culture of K. fragilis using Jerusalem Artichoke juice as substrate. And also the optimum condition of high ethanol productivity and low residual sugar output in the ethanol production by K. fragilis, was clarified to be given at a dilution rate of 0.22/hr and at an influent sugar concentration of 85g/l.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2002.10a
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• pp.166-166
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• 2002

The response of environmental pollutants can be detected bioanalytically focusing on the source and matrices of concern. Cell culture bioassays are rapid and inexpensive, and thus have great potential for determination of environmental pollution. We have examined the estrogenic and dioxin-like activites of industrial wastewater using E-screen assay and EROD microbioassay. Influent and effluent wastewater were collected from four different industrial wastewater treatment plants, such as cosmetics, paints, textile producing and metal coating plant, and extracted using solid-phase extraction with Oasis＠HLB plus cartridge. Pollutants adsorbed to the cartridge were eluted with MTBE. MCF-7 cells were treated with extracts showed various estrogenic potential. The textile wastewater showed strong estrogenic activity and the others showed weak estrogenic activity, No effect was observed in the wastewater from paints producing plant. All extracts showed CYPIA inducing effects, indicating these samples contain dioxin-like chemicals. Bioanalytical results of effluents compared with influents could give us information about the incomplete wastewater treatment and biological potency caused by pollutants. [Supported by a Grant from the Korea Science and Engineering Foundation]