• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11c
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• pp.777-783
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• 2000

Composting by negative aeration is a reasonable proposition to control odor generated during composting process. Cattle manure and rice hulls mixtures were composted in a bin composting system by negative aeration. Continuous(CA) and intermittent(IA) aeration methods were applied to analyze the composting characteristics. The composting temperature and the ammonia emission during composting were investigated according to the aeration methods. The main problem for the negative aeration was the generation of condensate in the suction line of blower. The quantity of condensate was significant for continuous aeration. The aeration method should be modified to escape from the cooling effect of continuous aeration at the initial stage of composting. It took a longer time to finish a composting for intermittent aeration on account of lower aeration. It was concluded that the composting by negative aeration could be accomplished by either continuous or intermittent aeration method if the flow rate would be controlled more efficiently and the water vapor in suction line of blower could be removed effectively. Ammonia emission increased up to maximum value of 675ppm for continuous aeration while 300ppm for intermittent aeration. However, the cumulative value of ammonia emission was larger for intermittent aeration than for continuous aeration.

• Journal of Korean Society on Water Environment
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• v.25 no.6
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• pp.872-878
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• 2009

Advanced Phase Isolation Ditch (APID) process was studied to develop economic retrofitting technology, for the plants where retrofitting of common activated sludge process is required. In this study, to develop and apply the modified intermittently aeration mode as process control conditions for treating municipal wastewater, a demonstration plant was installed and operated in the existing sewage treatment plant of P city. During this study, the average effluent $BOD_5$, SS, T-N, and T-P concentrations were 6.3, 4.5, 10.0, and 1.3 mg/L. The modified mode decreased the nitrification capability more than the conventional mode in the application period. Nitrate in the anaerobic condition can have a negative effect on biological phosphorus removal. In the decreasing nitrate levels, the modified mode increased the biological ability of removal phosphorus more than the conventional mode in this study. Therefore, newly developed APID process with modified intermittent aeration mode can be one of the useful processes for stable organic matter and nutrients removal.

• Agricultural and Biosystems Engineering
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• v.3 no.2
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• pp.59-64
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• 2002

Odor generated during composting of livestock manure is mainly due to ammonia emission. Biofiltration is a desirable method to control composting odor. This study was conducted to analyze the efficiency of using fresh compost as a biofilter. A mixture of cattle manure and recycled compost was composted in a bin equipped with a suction-type blower. The exhaust gas was filtered through the fresh compost. Residence time was controlled by the flow rate of exhaust gas and the depth of filtering materials. At the aeration rate of 30 L/min(experiment I), ammonia reduction rate varied from 100% to -15% for biofilter A(residence time 56.5 s) and almost 100% for biofilter B(residence time 113 s). At the aeration rate of 30 L/min, the cumulative ammonia reduction rate was 80.5% for biofilter A and 99.9% for biofilter B. At the aeration rate of 50 L/min(experiment II), the lowest reduction rate showed a negative value of -350% on the 8th and 9th day for biofilter A(residence time 33.9 5), and 50% on the loth day for biofilter B(residence time 67.8s). At the aeration rate of 50 L/min, the cumulative ammonia reduction rate was 82.5% fur biofilter A and 97.4% for biofilter B. Filtering efficiency was influenced by residence time. The moisture content(MC) and total nitrogen(T-N) of the filtering material were increased by absorbing moisture and ammonia included in the exhaust gas, while pH was decreased and total carbon(T-C) remained unchanged during the filtering operation.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.6
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• pp.472-481
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• 2000

This experiment used the enclosed bench-scale reactors was conducted to find out optimal aeration rate for reducing the emission of odors and producing the good-quality compost with the mixture of dairy manure and rice straw. The reactors with gas sampler were aerated at four different rates of 0.09, 0.18, 0.90 and $1.79l\;min^{-1}kg^{-1}$dry solids for 574 hours. The oxygen content within composting pile instantly decreased after aeration. Oxygen limitation(below 15%) in the treatments of $0.90l\;min^{-1}kg^{-1}$ and less was exponentially negative relationship with aeration rates and in the range of 35 to 300 hours after aeration. However, the treatment of $1.79l\;min^{-1}kg^{-1}$ didn't show the oxygen limitation. The oxygen consumption rate and the cumulative amount of oxygen consumed by different aeration rates was ranged in $0.80{\sim}1.57O_2g\;h^{-1}\;kg^{-1}VS^{-1}$, $460{\sim}900O_2g\;kg^{-1}VS^{-1}$, respectively, and they were high in the order of 0.90, 1.79, 0.18, $0.09l\;min^{-1}kg^{-1}$. The maximum oxygen consumption rate was estimated in the range of $1.2{\sim}1.3lmin^{-1}kg^{-1}$. The emission concentrations of sulfur compounds such as hydrogen sulfide, sulfur dioxide and methylmercaptan were remarkably high in the initial composting time. Then they were rapidly decreased with the passing of composting time and clearly with increasing aeration rates. Their average concentrations were in the range of 0.03~2.18, 0~0.50, $0.07{\sim}3.38mg\;kg^{-1}$, respectively and high in the order of methylmercaptan, hydrogen sulfide, and sulfur dioxide. Concentrations of sulfur compounds emitted from composting showed exponentially negative relationship at 1% statistically with the oxygen concentration. It was estimated that hydrogen sulfide and methylmercaptan suddenly increased in the level of 5% oxygen concentration and below, that they were little emitted in 15% and over but sulfur dioxide was emitted in the level of 20% oxygen.

• Journal of Microbiology and Biotechnology
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• v.8 no.4
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• pp.341-346
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• 1998

Optimization for the production of Pest an was followed by the Plackett-Burman Design, using modified Czapek-dox medium as the starting point. At the flask level, $K_2HPO_4$, $MgSO_4{\cdot}7H_2O$, and aeration variables positively affected the Pestan production, DCW (dry cell weight), apparent viscosity, and flocculating activity response. KCI and $FeSO_4{\cdot}7H_2O$ negatively affected the Pestan production, DCW, apparent viscosity, and flocculating activity response. Aeration variable was shown to have a positive effect on only the flocculating activity response among Pestan production, DCW, and apparent viscosity responses. In comparison of the positive and negative variables media conditions, Pestan production and flocculating activity differed by about 9 and 125 times, respectively. In particular, at the jar fermentor level, the aeration variable was the most important factor of the all responses (pestan production, DCW, apparent viscosity, flocculating activity, and anionic charge density). The flocculating activity and apparent viscosity of Pestan were closely related to the molecular chain length and charge density.

• Korean Journal of Microbiology
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• v.15 no.2
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• pp.63-76
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• 1977

Irradiation with high doses of gamma rays induced the reduction of mycelial weight and anaylase activity, and increased relative amylase activity in surface cultures. Biphase in growth curves was shown in aeration-agitation cultures but the behavior of the first phase of growth could be eliminated by replacing the amylasehydrolysed starch substrates, so that enzyme production was shortened ca. 40 hours and relative amylase activity was increased about 3 times higher before onset of autolysis. In the effect of gibberellin on amylase production, the positive stimulation was appeared to only surface culturs of the liquid medium and the negative effect to shake-cultures in a mutant. Trials of various continuous culture were resulted not only the approalch to the value of amylase activity in surface cultures of liquid medium, but also higher productivity than in batch cultures. The culture-degeneration was observed in two-stage continuous culture, but did not appear in continuous elevation culture.

• Journal of the Korea Organic Resources Recycling Association
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• v.2 no.2
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• pp.19-29
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• 1994

A large volume of paper mill sludge(PMS) is produced every day from paper industries after treatments of waste water and it costs too much to dispose of the sludge. Since PMS consists mostly of biodegradable organic matter, cellulose, it is desirable to recycle it by proper treatments such as composting. In this study, experiments were conducted using a small scale reactor(12l) to establish optimum conditions for efficient composting of PMS of which initial pH, C/N ratio, and moisture content were 7.1, 28~30, and 60~65%, respectively. No heavy metals such as mercury, cadmimum, and lead were not detected in the PMS. Various levels of forced aeration, 1 minute aeration per every 30, 60, 120, 240, and 480 minutes were applied and 1 minute aeration per 60 and 120 minutes found to be proper for composting of 8l PMS in this system. Relationship between $CO_2$ production and temperatures was positively correlated with r> 0.82 suggesting that the normal decomposition of PMS by microorganisms occurred. However, under the condition of aeration interval over than 240 minutes, a negative relationship between two parameters was found indicating the occurrence of abnormal(maybe anaerobic) degradation. The amount of added nitrogen also affected composting of PMS resulting in the increase of $CO_2$ production and temperature. Semi-field tests using 100kg PMS in a static pile sysem showed that PMS could be composted efficiently under optimal environmental conditions. The parameters determining efficiency of composting such as C/N ratio, aeration, moisture content, and pH need to be monitored.

• Korean Journal of Microbiology
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• v.11 no.3
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• pp.121-128
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• 1973

In order to clarify the best cultural conditions of Rhizopus niveus the effects of aeration, pH and various nutrients, such as different carbon and nitrogen sources, vitamins, and growth substances, on the mycelial growth were studied through liquid culture, and amylase activities of the fungus at different cultural periods were measured. Soluble starch, xylose and galactose are excellent sources of carbon for growth of the fungus. Sorbose and lactose are utilized slightly for growth. peptone, ammonium sulfate and alanine are excellent nitrogen sources for growth, tyrptophane nad potassium nitrate are utilized slightly for growth and sodium nitrite is not utilized. Thiamine nad gibberellin are excellent growth substances for the fungal growth, and biotin, nicotinamide and indole acetic acid (IAA) are also effective. Rhizopus niveus grows better at rotatory culture than at stationary culture and earlier growth of the fungus increases remarkably at rotatory culture. Optimum pH than at pH3. Growth increases linerly with an increase of soluble starch content up to 100g per liter medium, but 5 grams of ammonium sulfate per liter is the optimum nitrogen concentration for growth, if Pfeffer's medium is employed. Amylase activities of Rhizopus at different cultural periods showed that the maximum amylase production takes place after the cell population has reached its peak in the culture. Dextrinogenic amylase production has reached maximum at stationary phase, and maximum saccharogenic maylase production takes place in the pahse of negative gorwth acceleration.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.6
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• pp.896-902
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• 2015

Milking center wastewater (MCW) has a relatively low ratio of carbon to nitrogen (C/N ratio), which should be separately managed from livestock manure due to the negative impacts of manure nutrients and harmful effects on down-stream in the livestock manure process with respect to the microbial growth. Simultaneous nitrification and denitrification (SND) is linked to inhibition of the second nitrification and reduces around 40% of the carbonaceous energy available for denitrification. Thus, this study was conducted to find the optimal operational conditions for the treatment of MCW using an attached-growth biofilm reactor; i.e., nitrogen loading rate (NLR) of 0.14, 0.28, 0.43, and $0.58kg\;m^{-3}\;d^{-1}$ and aeration rate of 0.06, 0.12, and $0.24\;m^3\;h^{-1}$ were evaluated and the comparison of air-diffuser position between one-third and bottom of the reactor was conducted. Four sand packed-bed reactors with the effective volume of 2.5 L were prepared and initially an air-diffuser was placed at one third from the bottom of the reactor. After the adaptation period of 2 weeks, SND was observed at all four reactors and the optimal NLR of $0.45kg\;m^{-3}\;d^{-1}$ was found as a threshold value to obtain higher nitrogen removal efficiency. Dissolved oxygen (DO) as one of key operational conditions was measured during the experiment and the reactor with an aeration rate of $0.12\;m^3\;h^{-1}$ showed the best performance of $NH_4-N$ removal and the higher total nitrogen removal efficiency through SND with appropriate DO level of ${\sim}0.5\;mg\;DO\;L^{-1}$. The air-diffuser position at one third from the bottom of the reactor resulted in better nitrogen removal than at the bottom position. Consequently, nitrogen in MCW with a low C/N ratio of 2.15 was successfully removed without the addition of external carbon sources.

• Journal of the Korea Organic Resources Recycling Association
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• v.15 no.1
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• pp.123-133
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• 2007

The presence of antibiotics in the wastewater from livestock farm due to its over-application should be concerned because they could change microbial ecology, increase the proliferation of antibiotic resistant pathogens, provoke toxic effect on aquatic species. In addition, these antibiotics can cause negative effect on the performance of biological wastewater treatment due to its antibacterial properties. In this study, our aim is to evaluate the effect of some common used antibiotic in Korea piggery farm such as oxytetracycline (OTC) to nitrification efficiency as well as organic compounds removal rate in biological system for treating piggery wastwater. The experiment was conducted in aeration batch reactor and lab-scale $A_2/O$(Anoxic-Anoxic-Oxic) system. From this study, it would be suggested that the piggery wastewater characterization should be examined in order to assess the fraction of common used antibiotics. The alternative treatment processes for piggery wastewater having high-strength antibiotics might be suggested in the future work.