• 유기물자원화
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• 제4권1호
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• pp.13-21
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• 1996

고농도 황산염과 중금속을 함유한 피혁폐수를 처리하기 위하여, 반응조의 처리도, 황환원균과 메탄균 사이의 기질경쟁 및 크롬농도에 대한 메탄균의 활성을 평가하였다. COD는 $35^{\circ}C$의 반응조 온도에서 유기부하량 2.0 gCOD/l.day와 18시간의 수리학적 체류시간에서 70% 이상의 제거율을 얻을 수 있었다. 황환원균과 메탄균 사이의 기질경쟁에서 황환원균에 의해 이용된 COD는 운전초기 15%에서 실험종료시 43%까지 증가되었다. 이는 유기물 분해로부터 발생되는 대부분의 전자가 황환원균에 의해 이용되어 황산염 환원에 의한 황화물이 생성되므로 메탄균의 활성은 강력히 억제되었다. 전 실험기간 동안 크롬농도는 90% 이상 제거되었으며, 크롬농도의 높은 제거율에도 불구하고 반응조의 처리능력은 거의 감소되지 않았다. 이는 반응조내에서 제거된 3가 크롬이 미생물의 활성에 영향을 미치지 않은 점으로 볼 때 3가 크롬이 6가 크롬에 비해 미생물에 대한 독성영향이 심하지 않다고 볼 수 있다.

• 한국물환경학회지
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• 제26권5호
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• pp.754-760
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• 2010

This study was carried out not only to evaluate optimal operating condition to increase biogas production, but also to estimate feasibility of renewable energy from anaerobic digester of sewage sludge. Semi- continuous Fed and Mixed Reactors (SCFMRs) were operated in various condition to quantify the reactor variables. The result of SCFMR operation showed that the biogas productivity and total volatile solids (TVS) removal of total solids (TS) 4% reactor at hydraulic retention time (HRT) 20 days with Organic Loading Rate (OLR) of $1.45kg/m^3-d$ were $0.39m^3/m^3-d$ and 26.7%, respectively which was two times higher than that of TS 2.5% reactor. Consequently the daily biogas production of $20,000m^3$ would be possible from the total volume of $52,000m^3$ of anaerobic digesters of the municipal wastewater treatment plant in D city. In feasibility study for the Biogas utilization, combined heat and power system (CHP) and CNG gasification were examined. In case of CHP, the withdrawal period of capital cost for gas-engine (GE) and micro gas-turbine (MGT) were 7.7 years and 9.1 years respectively. biogas utilization as Clean Natural Gas (CNG) shows lower capital cost and higher profit than that of CHP system. CNG gasificaion after biogas purification is likely the best alternative for Biogas utilization which have more economic potential than CHP system. The withdrawal period of capital cost appeared to be 2.3 years.

• 한국물환경학회지
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• 제26권5호
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• pp.768-774
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• 2010

This study was conducted to provide a technical solution to treat effectively perchlorate from inorganic wastewater of zinc smelting. Despite an inhibition dissolved inorganic substances in the wastewater discharged from zinc smelting has demonstrated with the activity of microbes, biological treatment technology could reduce perchlorate to a satisfactory level under such stressful conditions. It was found that either conductivity or $SO{_4}^{2-}$ concentration of the wastewater was able to be used as the adequate index and the values were $2,450{\mu}S/cm$ and 1,200 ppm respectively. When $SO{_4}^{2-}$ increased from 0 to 16,000 ppm (conductivity : $428{\rightarrow}24,800{\mu}S/cm$), perchlorate biodegradation rate was reduced due to 1/10 times from 0.0365 to 0.0033/h, however, most of perchlorate was removed under the condition of hydraulic retention time (HRT) at 0.5day and mixed liquor volatile suspended solid (MLVSS) at 2,000 ~ 3,000 ppm.

• 상하수도학회지
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• 제21권3호
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• pp.331-339
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• 2007

The purpose of this study was to investigate the biodegradability and performance of organic removal and methane production rate when treating piggery wastewater using a pilot scale two-phase anaerobic system operated up to a volumetric rate of $10m^3/day$. The pilot scale two-phase anaerobic process is consisted of a continuous-flow stirred-tank reactor (CFSTR) for the acidification phase and an Upflow Anaerobic Sludge Blanket reactor (UASB) for the methanogenesis. The acidogenic reactor played key roles in reducing the periodically applied shock-loading and in the acidification of the influent organics. The acidogenic CFSTR was operated at organic loading rates (OLR) between 1.8 and $14.4kgCOD/m^3{\cdot}day$, and the UASB reactor was operated between 0.5 and $5.6kgCOD/m^3{\cdot}day$. A stable maximum biogas production rate was $81m^3/day$ and the methane conversion rate of the organic matter varied from 0.30 to $0.42L\;CH_4/g\;COD_{removed}$(0.40) at hydraulic retention time (HRT) above 3.5days. The methane contents ranged from 73 to 82% during the experimental period. It is known that most of the removed organic matter was converted to methane gas, and the produced biogas might be high quality for its subsequent use.

• 유기물자원화
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• 제15권2호
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• pp.136-146
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• 2007

상향류 혐기성 블랭킷 반응조를 이용한 매립지 침출수 처리시 입상슬러지 첨가 유무에 상관없이 성공적인 처리가 가능하였다. 입상슬러지의 첨가는 초기 운전기간를 현저히 단축할 수 있었다. 수리학적 체류시간 1일과 $4-8kgCOD/m^3.d$ 의 유기물 부하율에서 Control 반응조와 Granule 반응조의 COD 제거율은 90% 이상을 유지하였다. 실험기간 동안 입상슬러지 첨가 유무에 상관없이 슬러지 표면과 반응조 벽면에 무기 침전물이 축적되었다. 비메탄 활성도는 미생물의 기질에 대한 적응도와 유기물 부하량이 증가함에 따라 증가하였다. Granule 반응조의 최대 비메탄 활성도의 값은 $0.57gCOD/g{\cdot}VSS{\cdot}.d$로 나타났다. 비록 본 연구에서는 과도한 무기물 축적으로 인한 비메탄 활성도의 저감은 발생하지 않았으나 무기물의 제거를 위하여 유입수의 전처리 공정이 필요할 것으로 판단된다.

• 한국물환경학회지
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• 제21권5호
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• pp.528-534
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• 2005

Ozone, a powerful oxidant, is widely used to remove microorganisms, pesticides, taste and odor compounds effectively. Dissolved air flotation (OAF) has been known as an economical process for treating algae and low turbid water quality. An ozoflotation system, combining ozone and OAF processes, has a merit which can operate the ozonation and flotation process simultaneously in a single compartment. This study investigated the application of the ozoflotation process for advanced water treatment by carrying out the pilot-plant experiment. During the test, ozone microbubbles were generated through a OAF pump and many kinds of parameters were evaluated under several conditions, such as raw water flow rate and ozone dose. As a result of the test, the optimum operating conditions of ozoflotation were decided to be 1.2 mg/L ozone dose and about 34 minute Hydraulic retention time (HRT). Finally, it could be demonstrated that the ozoflotation system can effectively improve the drinking water quality.

• 한국축산시설환경학회지
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• 제6권2호
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• pp.83-89
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• 2000

In general, livestock wastewater consists of many pollutants such as nitrogen, phosphorus, carbonic compounds and inorganic substances. Most carbonic and organic compounds are sufficiently removed by conventional secondary processes, but nitrogen, phosphorus and soluble inorganic compounds are little removed by traditional clarification process. These remained substances in wastewater, for instances, phosphorus and nitrogen are efficiently eliminated by advanced wastewater treatment or botanical removing process. Concentrations of $BOD_s$, SS, T-N and T-P in influent livestock wastewater used in this study were 126mg/l, 115mg/l, 45mg/l and 13mg/l, respectively. The hydraulic retention time(HRT) of wastewater was about 10 days in the pond packed with aquatic plants. A water-hyacinth and a water-dropwort were used as an experimental stuff plant. The removal ratios of nitrogen was 44.3% for the water-hyacinth and 40.2% for the water-dropwort. The removal efficiency of phosphorus in experimental ponds reached by 57.9% for the water-hyacinth and 58.5% for the water-dropwort for 10 days, respectively. Removal ratios of BODs and SS of livestock wastewater for 10 days were reached by 80.1%, 91.0% for he water-hyacinth, respectively. At the same condition, the removal ratios of BODs and SS were reached by 75.0%, 87.6% for the water-dropwort, respectively.

• Journal of Microbiology and Biotechnology
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• 제22권5호
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• pp.668-673
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• 2012

Biohydrogen production from organic wastewater by anaerobically activated sludge fermentation has already been extensively investigated, and it is known that hydrogen can be produced by glucose fermentation through three metabolic pathways, including the oxidative decarboxylation of pyruvic acid to acetyl-CoA, oxidation of NADH to $NAD^+$, and acetogenesis by hydrogen-producing acetogens. However, the exact or dominant pathways of hydrogen production in the anaerobically activated sludge fermentation process have not yet been identified. Thus, a continuous stirred-tank reactor (CSTR) was introduced and a specifically acclimated acidogenic fermentative microflora obtained under certain operation conditions. The hydrogen production activity and potential hydrogen-producing pathways in the acidogenic fermentative microflora were then investigated using batch cultures in Erlenmeyer flasks with a working volume of 500 ml. Based on an initial glucose concentration of 10 g/l, pH 6.0, and a biomass of 1.01 g/l of a mixed liquid volatile suspended solid (MLVSS), 247.7 ml of hydrogen was obtained after a 68 h cultivation period at $35{\pm}1^{\circ}C$. Further tests indicated that 69% of the hydrogen was produced from the oxidative decarboxylation of pyruvic acid, whereas the remaining 31% was from the oxidation of NADH to $NAD^+$. There were no hydrogen-producing acetogens or they were unable to work effectively in the anaerobically activated sludge with a hydraulic retention time (HRT) of less than 8 h.

• Journal of Microbiology and Biotechnology
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• 제23권3호
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• pp.382-389
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• 2013

Propionate is an important intermediate product during the methane fermentation of organic matter, and its degradation is crucial for maintaining the performance of an anaerobic digester. In order to understand the effect of temperature on propionate degradation, an upflow anaerobic sludge blanket (UASB) reactor with synthetic wastewater containing propionate as a sole carbon source was introduced. Under the hydraulic retention time (HRT) of 10 h and influent propionate of 2,000 mg/l condition, propionate removal was above 94% at 30-$35^{\circ}C$, whereas propionate conversion was inhibited when temperature was suddenly decreased stepwise from $30^{\circ}C$ to $25^{\circ}C$, to $20^{\circ}C$, and then to $18^{\circ}C$. After a long-term operation, the propionate removal at $25^{\circ}C$ resumed to the value at 30- $35^{\circ}C$, whereas that at $20^{\circ}C$ and $18^{\circ}C$ was still lower than the value at $35^{\circ}C$ by 8.1% and 20.7%, respectively. Microbial community composition analysis showed that Syntrophobacter and Pelotomaculum were the major propionate-oxidizing bacteria (POB), and most POB had not changed with temperature decrease in the UASB. However, two POB were enriched at $18^{\circ}C$, indicating they were low temperature tolerant. Methanosaeta and Methanospirillum were the dominant methanogens in this UASB and remained constant during temperature decrease. Although the POB and methanogenic composition hardly changed with temperature decrease, the specific $COD_{Pro}$ removal rate of anaerobic sludge (SCRR) was reduced by 21.4%-46.4% compared with the control ($35^{\circ}C$) in this system.

• 한국환경과학회지
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• 제8권1호
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• pp.107-113
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• 1999

A new biological nutrient removal system combining $A^2/O$ process with fixed film was developed in this work and the characteristics of denitrification were especially investigated in the combined fixed film reactor(CFFR). Media was added in the anaerobic, anoxic and aerobic reactors, respectively. Tests were made to establish the effluent level of $NO_x-N$, COD, DO and nitrite effects on $NO_x-N$ removal in the CFFR by decreasing hydraulic retention time (HRT) from 10.0 to 3.5 hours and by increasing internal recycle ratio form 0% to 200%. The influent was synthesized to levels similar to the average influent of municipal wastewater treatment plants in Korea. SARAN media with a porosity of 96.3% was packed 40% / 130% / 25% based on its reactor volume, respectively. It was found that COD rarely limited dentrification in the anoxic reactor because of high $C/NO_x/-N$ ratio in the anoxic reactor, while DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent inhibited denitrification in the anoxic reactor. It was proved that the critical points of DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent were 0.15mg/L and 10%, respectively. As the internal recycle ratio increased, DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent increased. Especially, at the condition of internal recycle ratio, 200%, DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent exceeded the critical points of 0.15mg/L and 10%, respectively. Then, denitrification efficiency considerably decreased. Consequently, it was represented that the control of DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent can assure effective denitrification.