• Journal of Korean Society of Water and Wastewater
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• v.24 no.1
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• pp.109-117
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• 2010

In the present study, the degradation characteristics of Lindane by Advanced Oxidation Processes(UV/$H_2O_2$, Photo-Fenton process) were studied. The degradation efficiency of Lindane in aqueous solution was investigated at various initial pH values, Fenton's reagent concentrations and initial concentrations of Lindane. GC-ECD was used to analyze lindane. Lindane has not been degraded without application of AOPs over two hours. But, approximately 5% of lindane was degraded with UV or $H_2O_2$ alone. Lindane with UV/$H_2O_2$ process showed approximately 7% higher removal efficiency than $H_2O_2$ process. In the UV/$H_2O_2$ process, the pH values did not affect the removal efficiency. The optimal mole ratio of $H_2O_2/Fe^{2+}$ for lindane degradation is about 1.0 in Photo-Fenton process. Also, the experimental results showed that lindane removal efficiency increased with the decrease of initial concentration of lindane. Under the same conditions, the order lindane of removal efficiency is as following : Photo-Fenton process > UV/$H_2O_2$ process > $H_2O_2$ process. In addition, intermediate products were identified by GC-MS techniques. Than PCCH(Pentachlorocyclohexene) was identified as a reaction intermediate of the Photo-Fenton process.

• Journal of Animal Environmental Science
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• v.3 no.2
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• pp.115-123
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• 1997

This study was conducted to investigate the removal effect of malodorous substances of piggery wastes by air injection. With 7% of TS weight of artificial piggery wastes, this study focused on the changes of the concentration of VFAs, H2S during treatment period of 14 days. As a results of this study, air injection volume for removal of malodorants in this study was 150$m\ell$ / min$.$l$.$Under this condition, we found the concentrations of VFAs, H2S, NH3 have very high relationship with the pH, ORP, BOD, {{{{ { NH}`_{4 } ^{+ } }}-N. Especially, the concentration of Volatile Fatty Acids, one of most offensive odorants and one of BOD compounds were depended on ORP which can be controled by air injection in artificial piggery wastes.

• Journal of Animal Science and Technology
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• v.45 no.4
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• pp.641-648
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• 2003

In a batch mode treatment process, which electrolyzes the wastewater after derivation of N-P crystal formation and recovery, the characteristics of pollutant removal induced with the changes of loading rate and hydraulic retention time were studied. $MgCl_2$ was used as Mg source for the formation of struvite and the molar ratio of $MgCl_2$ to $PO_4^{3-}$ in influent was 1.3. When analyzing the average treatment efficiencies and removal characteristics obtained from four separate operations (Run I, II, III, IV), removal efficiencies of PO43- was not function of its loading rate. Under a condition of sufficient aeration and Mg source provided, over 88% of $PO_4^{3-}$ was eliminated by the formation of MAP without any pH adjustment, in spite of loading rate variation. An optimum-loading rate of NH4-N to achieve high removal efficiency was approximately $100g/m^3/d$. Below that loading rate, the removal of NH4-N was proportional to the loading rate into the system, and hence stable and high removal efficiency, over 90%, was achieved. However, when the loading rate increased over that rate, removal efficiency began to drop and fluctuate. Removal efficiency of TOCs was dependant upon the hydraulic retention time ($r^2$=0.97), not upon the loading rate. Stable and high color removal (94%) was obtained with 2 days of HRT in electrolysis reactor.

• Journal of Environmental Science International
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• v.30 no.2
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• pp.161-172
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• 2021

This study was initiated to isolate the microorganisms removing phosphorus (P) from domestic sewage and to investigate the effects of environmental factors on the growth and P removal of the isolated bacteria. Microorganisms isolated from the sewage were identified as Chryseobacterium sp., Stenotrophomonas maltophilia, and Bacillus licheniformis. Among them, Bacillus licheniformis was selected as the P removal microorganism. The environmental factors considered in this study included initial phosphorus concentration, temperature, pH, and carbon source. At initial P concentrations of 10, 20, and 30 mg/L, the P removal efficiencies were 100.0%, 84.0%, and 16.5%, respectively. At 20℃, 30℃, and 40℃, the P removal efficiencies were 0%, 75.8%, and 60.6%, respectively. The removal efficiencies of phosphorus according to pH were 1.6%, 91.7%, and 51.1% at pH 5, pH 7, and pH 9, respectively. Using glucose, acetate, and glucose + acetate as carbon sources yielded P removal efficiencies of 80.9%, 33.6%, and 54.1%, respectively. Therefore, the results from the study demonstrated that the P removal efficiencies of Bacillus licheniformis were the highest when the initial P concentration, temperature, pH, and carbon source were 10 mg/L, 30℃, 7, and glucose, respectively.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2000.04a
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• pp.19-22
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• 2000

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.917-921
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• 2002

In this paper, we made different types of non-thermal plasma reactors such as Metal-particle reactor with $Al_2O_3$ to measure NOx removal characteristic and the dielectric effect for NOx removal. NOx removal rate is not so good when we use just dielectric of $Al_2O_3$ at the Metal-particle reactor, also we just put sludge pellets(100%) without Metal-particle reactor with $Al_2O_3$ and dielectric such as $TiO_2$, $BaTiO_3$ to measure the effect of sludge for NOx removal so that NOx removal rate is almost the same. However NOx removal rate is more than 90% in case of the reactor of composition shape used both dielectric of $Al_2O_3$ and sludge pellets at the same time. In case of the shape of plasma reactor with dielectric, the Metal-particle reactor with $Al_2O_3$, and the metal-particle reactor with both $Al_2O_3$ and dielectric such as $TiO_2$, $BaTiO_3$ at the same time, they are almost the same effect for NOx removal, so we made MNPR(Metal-particle Non-thermal Plasma Reactor with $Al_2O_3$) to reduce these kinds of demerits. Finally, we think MNPR should be much better than other reactors for NOx removal.

• Microbiology and Biotechnology Letters
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• v.36 no.2
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• pp.165-172
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• 2008

To find the optimum growth and metal removal condition of isolated strain LH2, effects of the environmental factors such as medium pH, growth temperature, and metal concentrations were investigated. Based on the 18S rDNA analysis, the isolated strain was identified to Exophiala sp. with 100% homology. Isolated strain Exophiala sp. LH2 showed maximum removal efficiency of metals at the shaking conditions of pH 7 and $25^{\circ}C$. When the concentration of metal was under 200ppm, the specific metal removal velocity at pH 7 increased from 0.01 to 4.43 mg-metal $L^{-1}{\cdot}d^{-1}{\cdot}mg{\cdot}DCW^{-1}$ as the concentration of metal increased from 10 ppm to 200 ppm. When 200 ppm of each metal was contained in the culture medium adjusted with pH 7, metal removal efficiencies Cr, Cu, Ni, Pb and Zn were 99.28%, 97.67%, 91.94%, 99.77%, 99.61%, respectively.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.4
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• pp.481-491
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• 2015

The aim of this study was to evaluate the chemical quenching system for residual ozone and to determine the operating condition for the quenching system. Hydrogen peroxide ($H_2O_2$) and sodium thiosulfate ($Na_2S_2O_3$) were investigated as quenching reagents for ozone removal, and the tendency of each chemical was notably different. In the case of $H_2O_2$, the degradation rate of ozone was increased as the concentration of $H_2O_2$ increase, and temperature and pH value have a significant effect on the degradation rate of ozone. On the other hand, the degradation rate of ozone was not affected by the concentration of $Na_2S_2O_3$, temperature and pH value, due to the high reactivity between the ${S_2O_3}^{2-}$ and ozone. This study evaluates the decomposition mechanism of ozone by $H_2O_2$ and $Na_2S_2O_3$ with consideration for the water quality and reaction time. Furthermore, the removal test for the quenching reagents, which can be remained after reaction with ozone, was conducted by GAC process.

• Journal of Climate Change Research
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• v.8 no.1
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• pp.51-56
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• 2017

The objective of the research project is to develop the hybrid deodorizer for the removal of residual harmful gases generating during pretreatment process of biogas. This hybrid deodorizer is capable of treating harmful gases that contains hydrogen sulfide ($H_2S$), ammonia ($NH_3$) and other odor substances. This hybrid deodorizer reduced the hydrogen sulfide content from approximately 150~200 ppm to less than 16 ppm. These residual harmful gases were effectively removed in the effluent, achieving up to 97% removal of $H_2S$ and 94% removal of $NH_3$ after treatment using hybrid deodorizer.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.6
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• pp.811-817
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• 2013

A two-stage bioreactor system using sulfur-oxidizing bacteria was studied to abate high strength hydrogen sulfide ($H_2S$) from biogas. The two-stage bioreactor consisted of a $H_2S$ absorption column (0.5 L) and a microbial oxidation column (1 L) in series, and the liquid medium was continuously recirculated through the columns. The objectives of this study were to determine the feasibility of the bioreactor for biogas desulfurization and to investigate the effect of the medium circulation rate on the system performance. An averaged concentration of $H_2S$ introduced to the bioreactor was 530 ppm, corresponding to an overall loading rate of $44.4g/m^3/hr$. During the initial 20 days period at the medium recirculation rate of 8 reactor volumes per hour (12 L/hr), the dissolved oxygen (DO) concentration in the oxidation column was 6 mg/L, while the DO in the absorption column was 0.5 mg/L showing that the oxygen contents of the biogas stream was not altered. Because of the biological oxidation of $H_2S$ in the oxidation column, the sulfate concentration increased from 200 mg/L to 5,600 mg/L in the liquid medium. The removal efficiency of $H_2S$ was greater than 99% in the initial operation period. After the initial period, the medium recirculation rate between the two columns was stepwise changed eight times from 1.0 to 40 vol/hr (1.5~60 L/hr). At the recirculation rate of faster than 4 vol/hr, the $H_2S$ removal efficiencies were found to be high, but the efficiency declined at the lower recirculation rates than the threshold.