• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.611-614
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• 2003

A Korean Type Biofilter system combined with a conventional anoxic tank(septic tank) process was investigated in regard to its feasibility for removing organic as well as nutrients from the rural wastewater in Korea. At recirculation, the removal rate in BOD and SS increased slightly as much as 93 and 95% compared with non-recirculation system. On the other hand, removal rates of the total nitrogen(T-N) and total phosphorous(T-P) in recirculation system increased significantly as much as 62 and 57%, respectively compared with non-recirculation system. The recirculation system provides sufficient treatment to improve the removal rate in T-N and T-P.

• Korean Journal of Microbiology
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• v.29 no.2
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• pp.117-122
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• 1991

In order to improve the removal ability of phosphate, Spheroplast fusions were performed among auxotrophic mutants of Aeromonas hydrophila isolated from waste water, named A13 and A14, Aci37 auxotrophic mutant of Acinetobactercalcoaceticus, and auxotrophic E. coli HR262/pCE27 carring pit gene. Eight fusants obtained from this experiment showed different biochemical characteristics. When the rate of phosphate uptake among fusants (F1-F8) was investigated in Phosphate Uptake Medium (PUM), F8 strain showed the highest rate for phosphate removal, 7 times as much as control after two hours incubation. The role of cations ($Mg^{++}$ ,$Ca^{++}$ , $K^{+}$ in phosphate uptade by F8 was also investigated in PUM without each salt. $K^{+}$ seemed to be crucial. Being compared with phosphate untake rate in PUM, that in PUM without $K^{+}$ was reduced 1.5 times. Therefore, by applying F8 strain and $K^{+}$ in practical environmental system, the increased efficiency in phosphate removal can be derived.

• Journal of environmental and Sanitary engineering
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• v.11 no.3
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• pp.21-27
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• 1996

Chitosan is a natural polyelectrolytic compound. Researches of adsorption capacity using chitosan have been doing actively. We prepared bead type gel, simple modifier of chitosan, And then experimented adsorption test of heavy metals (Cd etc) using it. According to the result adsorption capacity of chitosan bead was five times higher than chitosan powder. Removal rate of cadmium resulted 90% over in the test that initial concentration of Cd was 100mg/L and bead dosage was 6g/100mL. Adsorption type of heavy metals was similar to general adsorption curve. And optical pH range was 4 - 10 in the adsorption test. In the experiments of other heavy metals (Pb, Zn, Cu, Mn) adsorption types had two stages, highly removal rate-stage at the short time (20minutes) and then slow rate-stage at the after. And removal efficiency at the variable pH ranges revealed relatively good.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.E2
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• pp.41-48
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• 2005

A novel hybrid system composed of a biotrickling filter and an activated sludge reactor was investigated under the conditions of four different SRTs (sludge retention times). The performance of the hybrid reactor was found to be directly comparable among the four different sludge ages. Discernible differences in the removal performance were observed among four different SRTs of 2, 4, 6, and 8 days. High removal efficiency was achieved by continuous circulation of activated sludge over the immobilized mixture culture, which allowed on pH control, addition of nutrients, and removal of paint VOCs (volatile organic compounds). The results also showed that the removal efficiency for a given pollutant depends on the activity of microorganisms based on the SRT. As the SRT increased gradually from 2 to 8 days, the average removal performance decreased. The highest removal rate was achieved at the SRT of 2 days at which the highest OUR (oxygen uptake rate), $6.1mg-O_2/liter-min$ was measured. Biological activity in the recycle microbes decreased to a much lower level, $3.6mg-O_2/liter-min$ at a SRT of 8 days. It is thus believed that young microorganisms were more active and more efficient for the VOCs removal of low concentrations and high flow rates. The apparent correlation of $R^2=0.996$ between the average removal efficiency and the average OUR at each SRTs suggests that VOCs degradation by young cells significantly affected the overall removal efficiency for the tested SRTs.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.468-474
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• 2005

SOx and NOx are known major precursors of acid rain and thus the abatement of their emissions is a major target in air pollution control. To obtain basic data on the removal process of simultaneous $SO_2/NO$, the optimal reaction condition and the composition of reaction solution for simultaneous removal of $SO_2/NO$, ware investigated using a bubble column reactor. Pilot scrubber was consisted of scrubber, filter and control box. Dust removal rate was 83, 92, and 97% with catalyst flux of 0.5, 0.8, 1.5 L/min, respectively Average dust removal efficiency with a kind of nozzle was about 94 and 90% in STS FF6.5 (5/8in.) and 14 of P.P W(1.0in.), respectively Dust and $SO_2$ were removed more than 98-96% regardless of reactor number. In the case of NO gas, removal yield of 83.3% was achieved after 48 hours in 1 stage, also removal yield of 95.7% was reached in 2 stages. In tile case of application of STS (5/8 in.) and P.P (1.0 in.) as used fill packing, removal efficiency was reached higher than 98% without related to of kind of fill packing.

• Journal of Environmental Health Sciences
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• v.26 no.4
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• pp.15-20
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• 2000

The studies of swine wastewater treatment aim to development of process using soil microorganism. Removal rate of swine wastewater containing organic matter was 99 percent in case of high loading rate. Microorganism was devoted to improve the treatment efficiency of the process. According to the result obtained from biological treatment of high loading rate swine wastewater. Hydraulic retention time was 2.3 days in unit process of biological phosphorus removal. BO $D_{rm}$ / $P_{rm}$ ratio was 1122 in room temperature anaerobic process and 355.6 in mesophilic anaerobic process. And then phosphorus removal rate mesophilic anaerobic process was 3 time as much as than room temperature acaerobic process.

• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.41-45
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• 1999

Simulated liquid waste containing 50 ppm cobalt ion was treated by precipitate flotation using the surfactant of sodium lauryl sulfate. The effects of initial cobalt ion concentration, pH, surfactant concentration, removal time, gas flow rate and foreign ions were estimated on removal efficiency. 35% $H_2O_2$ was added for pre-treatment stage before precipitate flotation. As the result of pre-treatment, optimum removal pH and the pH of treated water being discharged were lowed and optimum removal pH range was broadened. For the result of this experiment, 99.8% removal efficiency was obtained at the condition of 50ppm of initial cobalt ion concentration, pH 9.5, 70 mL/min of gas flow rate, and 30 min of removal time. Attraction between precipitate and surfactant was supposed to be influenced by solubility and chemical affinity among species in sloution as well as zeta potential. The influence of foreign ions such as, $NO_3{^-}$, ${SO_4}^{-2}$, $Na^+$, $Ca^{+2}$ on the removal efficiency was also observed. Removal efficiency by precipitate flotation containing 0.1 M of ${SO_4}^{-2}$ ion decreased to 90% due to the decrease of zeta potential and interruption of precipitation.

• Journal of Environmental Health Sciences
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• v.32 no.1 s.88
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• pp.27-35
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• 2006

This study was carried out to investigate the removal of nitrogen and phosphorus in municipal sewage depending on existence of biological coated media in BCM reactor. The reactor with biological coated media is the process combining $A_2/O$ process. The removal efficiencies for $COD_{Mn},\; BOD_5,\;SS$, T-N and T-P were $78\%,\;90.5\%,\;92.3\%,\;61.9\%,\;60.2\%$, respectively. The specific nitrification rate$(mgNO_3-N/gMLSS{\cdot}d)$ of Contact aeration basin was 52.2 and the specific denitrification rate$(mgNO_3N/gMLSS{\cdot}d)$ in anoxic basin was 95.1. Also, phosphorus release$(mgPO_4-P/gMLSS{\cdot}d)$ in Anaerobic basin was 71.8 and Phosphorus uptake$(mgPO_4-P/gMLSS{\cdot}d)$ in contact aeration was 27.1.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.4
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• pp.273-280
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• 1998

The investigation on the removal of 502 gas fro.In flue gas which causes serious air pollution was made by using a semi dry flue gas desulfurization method. Experiments were carried out as a function of process variables which would affect SO2 removal efficiency. Process variables inclilded SO2 inlet concentration, inlet temperature of simulated flue gas, sorbent weight fraction, and volume flow rate of sorbent slurry. In this study, used sorbent was Ca(OH), and simulated flue gas was prepared by mixing pure SO2 gas with air. Experimental conditions were varied at 140~18$0^{\circ}C$ of inlet temperature of the simulated flue gas, 500~2000ppm of inlet SO2 concentration, 0.4~1.0% of sorbent concentration, and 10~25 mL/min of flow rate of sorbent slurry. Among process variables, inlet concentration of SO2 was found to be the most significant factor to affect SO2 removal efficiency. The concentration of Ca(OH2) had a lower effect on SO2 removal than SO2 inlet concentration removal amount was 0.108, 0.141, 0.153 g SO2/g Ca(OH)2 respectively- As 200 mmol of HNO3 was added into slurry to improve removal efficiency, initial pH was maintained and solubility of slurry increased, so that removal efficiency elevated. Adding over 200 mmol of HNO3 into slurry caused removal efficiency lower. Therefore it could be concluded the optimum was 200 mmol of HNO3 input.

• Microbiology and Biotechnology Letters
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• v.13 no.1
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• pp.33-39
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• 1985

The effects of initial concentration, flow rate, and recycle ratio on the removal efficiency of phenol were studied in a tapered fluidized bed reactor packed with activated carbon which was attached with Candida tropicalis. The optimum conditions of Candida tropicalis were showed that pH was 7.0 and temperature was $30^{\circ}C$, and the specific growth rate of Candida tropicalis was satisfied with the Monod equation up to 500 mg/L of phenol, and beyond it the inhibition of substrate was found. According to the increases of initial concentration and flow rate, the removal efficiency was decreased, as the recycle ratio was increased, the removal efficiency was increased. In the case of flow rate of 10mL/sec and the recycle ratio of 2, the removal efficiency was 90% above for the all of initial concentration. The removal rate of phenol was the first order reaction in this system, and the rate equation of reaction was as follows.