• 한국환경보건학회지
• /
• 제34권4호
• /
• pp.327-332
• /
• 2008

To determine structure and activities of microbial communities in a food wastewater treatment system, biofilm of RABC (rotating activated Bacillus contactor) and samples of aeration tanks were analyzed. Heterotrophic bacterial concentrations were similar between biofilm and stage 1 aeration tank and decreased 2-log at stage 3 aeration tank as dissolved oxygen decreased, however portions of Bacillus groups were increased at stage 3 aeration tank. It was revealed by quantitative and qualitative analysis of metabolic fingerprinting patterns of Biolog GN2 plate that RABC represented much higher activities and a different microbial community structure compared to aeration tanks. Metabolic fingerprinting showed the carbon sources that isolated Bacillus groups could or could not use, were used similarly meaning that not only Bacillus groups but also other microbial groups would contribute to the treatment of wastewater.

• 상하수도학회지
• /
• 제22권5호
• /
• pp.523-529
• /
• 2008

Algal blooms in a local eutrophic lake often produces the musty and earthy taste & odor problems. Since the odor causing compounds(OCCs) including geosmin and 2-MIB have their own volatility, the OCCs can be removed from water by air stripping methods. Removal of TON(threshold odor number) as an index for OCCs could be fitted well with the first order equations($R^2=0.9$ above), where the air stripping coefficient of TON, k was in the range between 0.0055 and 0.0097 according to the aeration time. k within 30min aeration tests was 0.0097, while it was 0.0055 where the aeration time extended to 150min. With 15 mg/L of PAC, removal of TON was not simulated with 1st order equation within 30min aeration. Within 30min aeration, OCCs rather than geosmin and/or 2-MIB could be removed easily by air stripping or PAC adsorption, while OCCs such as geosmin and/or 2-MIB could be removed slowly by air stripping after 30min aeration. Geosmin and 2-MIB were not readily removed by air stripping(k of them were 0.0018~0.0047 and 0.0018~0.0034, respectively at different air flow rates). Geosmin could be removed by air stripping a little better than 2-MIB.

• 한국환경보건학회지
• /
• 제22권2호
• /
• pp.58-68
• /
• 1996

This study was performed to evaluate the effect of aeration rate on cornposting of mixture of swine feces and newspaper. This study was accomplished by operating 4 experimental cornposting reactors of bench scale for 3 weeks. The followings are the conclusions that were derived from this study. 1. As the aeration rate increased from 200 to 500 ml/min$\cdot$kg_vs, the efficiency of composting was increased. But the aeration rate more than 500 ml/min$\cdot$kg_vs did not influence effectively. 2. The range of the highest temperatures of reactors was 51.8~55$\circ$C. Those were not significantly different one another. 3. Increasing rates of ash content namely, reaction rates of composting were proportionally increased by increasing aeration rate from 200 to 1500 ml/min$\cdot$kg_vs. 4. Contents of heavy metal in the final compost were. lower than those of Korean and European standards. 5. Concentration range of T-N in the final composts was 1.7~2.18 mg/kg, and that of T-P was 1.57~7.49 mg/kg.

• Journal of Biosystems Engineering
• /
• 제29권6호
• /
• pp.508-514
• /
• 2004

This study was conducted to investigate the influences of aeration rates and temperatures on phosphorus transformation in the manure during treatment of swine manure in 15.3L batch reactor. The total phosphorus of raw manure was composed of $91.5\%$ of inorganic phosphorus and $8.5\%$ of organic phosphorus. During the experiment, inorganic phosphorus decreased from $91.5\%\;(385.7\;mg/L)\;to\;25.8-42.7\%\;(108.8-179.8\;mg/L)$ while organic phosphorus increased from $8.5\%\;(35.6\;mg/L)\;to\;57.3-74.2\%\;(241.5-312.5\;mg/L)$. The organic phosphorus was increased by the possible transformation of soluble inorganic phosphorus to poly-phosphate by the microbial uptake. However, soluble inorganic phosphorus was not decreased much during the experiment because the insoluble inorganic phosphorus was transferred to soluble inorganic phosphorus offsetting the microbial uptake. There was no significant difference in soluble inorganic proportion variance during the experiment among treatments for three liquid temperatures and three aeration levels. In terms of phosphorus transformation in the manure and energy consumption required for aeration, lower aeration was desirable fur the manure treatment.

• Fisheries and Aquatic Sciences
• /
• 제11권4호
• /
• pp.224-228
• /
• 2008

With the aim of increasing the $CoQ_{10}$ production in mass culture, the effect of aeration-agitation on the $CoQ_{10}$ production using Rhodobactor sphaeroides was investigated in a l-L bioreactor. The maximum $CoQ_{10}$ production was 1.69 mg/g of dry cell weight under conditions of 50 Lux, $30^{\circ}C$, 300 rpm, and 5-vvm aeration. The $CoQ_{10}$ production was improved to produce 2.91 mg/g of dry cell weight under reduced conditions of agitation speed (200 rpm) and aeration rate (0.2 vvm). When R. sphaeroides was cultivated under more reduced DO levels during the exponential phase of the cell, the $CoQ_{10}$ production yield of 3.88-mg/g dry cell weight was the maximum obtained. Therefore, poorer conditions of aeration-agitation resulted in higher production of $CoQ_{10}$, and thus DO content was a crucial factor in the production of $CoQ_{10}$. Accordingly, it was necessary to control the DO concentration in order to enhance the $CoQ_{10}$ biosynthesis within a large-scale production.

• 한국환경보건학회지
• /
• 제31권2호
• /
• pp.152-159
• /
• 2005

Laboratory scale experiments were conducted to study the applicability, and to compare the performance of two types of sequencing batch reactor (SBR)systems, a conventional SBR and sequencing batch biofilm reactor (SBBR) on the biological nitrogen and phosphorus removal. The nitrification rate in SaR was higher than that in SBBR both in high influent TOC concentration. The denitrification was completed at the first non-aeration period in SBR, however, the additional non-aeration period should be installed or the first aeration period should be extended more in order to complete the nitrogen removal in SBBR. The time at the first aeration period was more needed as about 4-5 h in order to uptake all the released $PO_4^{3-}\;-P$ at the first non-aeration period. SBBR needed more operation time, especially the first aeration time, than SBR at the high influent TOC concentration in order to complete nitrogen and phosphorus removal.

• 대한환경공학회지
• /
• 제35권1호
• /
• pp.38-44
• /
• 2013

D하수처리장의 송풍량을 효과적으로 조절하는 시스템을 구축하기 위해 2011년 1월 1일부터 2012년 8월 31일까지 포기조 DO 농도를 평균 2.1 mg/L로 유지하면서 유입유량, 유입농도, 유입부하, 수온, F/M비, 생물반응조의 MLSS 농도 변화에 따른 송풍량 변화를 검토하였다. 그 결과 동일한 DO 농도를 유지하기 위한 송풍량 변화폭은 매우 크며, 송풍량 산정을 결정하는 주요 인자는 수온, F/M비, $BOD_5$ 유입 부하, T-N 유입 부하로 나타났다. 그 중 가장 큰 영향을 주는 지표는 수온으로 수온 $1^{\circ}C$ 증가는 $45.8m^3/h$의 송풍량을 증가시키는 것으로 나타났으며, 이는 계절의 영향이 반영된 것으로 사료 된다. 하절기에는 유입 유량증가, 낮은 MLSS농도, F/M비 증가의 영향과, 동절기에는 유입 유량감소, 높은 MLSS농도, F/M비 감소 등의 영향이 송풍량에 반영되어, 수온 변화에 따른 필요 송풍량 변화를 더욱 가중시킨 것으로 사료된다. 따라서 호기조 송풍량 산정 시에는 유입유량, 유입 $BOD_5$농도, 유입 T-N농도 및 생물반응조의 MLSS농도 중 하나의 인자를 이용하는 것보다, 유입부하나 F/M비로 연산하여 접근이 필요한 것으로 사료된다.

• 한국물환경학회지
• /
• 제22권6호
• /
• pp.1119-1122
• /
• 2006

Aeration by using diffusers usually requires approximately 50~90% of the total electricity needed to operate WWTP (WasteWater Treatment Plant)s. Accurate evaluation of the oxygen transfer efficiency for an aeration system, and recommendation of a better alternative may help saving WWTP operational costs. Appropriate techniques and methods to achieve this purpose have not been introduced in Korea. In this study, in-process analysis was performed for a coarse bubble aeration system by the off-gas method to evaluate its applicability in Korea. To accomplish this analysis, an off-gas test, unsteady-state clean water test and steady-state off-gas column test was conducted and comparisons to other aeration systems were made. The ${\alpha}$ and the F estimated from the results of the unsteady-state clean water test and the steady-state off-gas column test were 0.61 and 0.90 respectively in a coarse bubble aeration system. The comparison of P.E tube diffusers laid out single spiral roll and ceramic dome diffusers laid out full floor coverage showed that the oxygen transfer efficiency of the coarse bubble aeration system was less than or similar to other aeration systems. But, airflow rates per unit area were 4~5 times greater than other aeration systems. In regards to the oxygen transfer efficiency for airflow rates per unit area, a retrofit to higher efficiency diffusers was urgently needed. This study showed proved that off-gas methods can apply to evaluate diffuser performances to estimate operating factors and to compare other aeration systems in Korea.

• Journal of Biosystems Engineering
• /
• 제31권1호
• /
• pp.46-51
• /
• 2006

This study was carried out to recover phosphorus in animal wastewater using a magnesium source. $MgCl_2$, as a magnesium source, was shown a SP (soluble phosphorus) recovery rate of 98% in both the aeration and the NaOH tests to adjust pH around 8.5. In case of MgO, the recovery rate of SP were 88% with the aeration and 58% with the NaOH. In case of ammonia nitrogen recovery, $MgCl_2$ was shown the recovery rate of 17% with aeration and 18% with NaOH. MgO was shown the ammonia recovery rate of 18% with aeration and 11% with NaOH. At low temperature of $6-8^{\circ}C$ with the animal wastewater from piglet stall, the recovery rate of SP was shown 95% with NaOH and 92% with aeration using $MgCl_2$. The recovery rate of ammonia nitrogen was shown 9% with NaOH and 12% with aeration, respectively. It was observed that the pH can be raised by aeration. The reaction was completed within 5 minutes and the struvite cristal structure was formed and could be observed with an electronic microscope.

• KSBB Journal
• /
• 제25권2호
• /
• pp.187-192
• /
• 2010

S. cerevisiae ATCC 24858을 이용한 ethanol 생산에서, aeration 효과를 ethanol 수율, specific ethanol production rate, ethanol 생산성 측면에서 분석하여, 반복 유가식 공정전략을 설계하였다. Ethanol 수율과 ethanol 생산성은 공기를 0.33 vvm 넣었을 때, 공기를 넣지 않고 배양한 것에 비하여 더 큰 값을 보였고, 24시간 마다 배지를 교체한 배양이 36시간 마다 배지를 교체한 배양 보다 더 큰 값을 보였다. 총 ethanol 생산량 값이 가장 큰 경우는 0.33 vvm의 공기를 넣고, 배지를 24시간마다 완전히 갈아주었을 때이고, 이때 가장 많은 703.8 g의 ethanol이 생산되었다.