• 한국환경보건학회지
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• 제21권4호
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• pp.1-9
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• 1995

This study was carried to investigate the biodegradability of phenol in the wastewater with the two sludge blanket-packed bed reactor in series. Each reactor had a dimension of 0.09 m i.d. and 1.5 m height and consisted of two regions. The lower region was a sludge blanket of 0.5 m height and the upper region was a packed-bed of 1 m height. The packed bed region was charged with ceramic raschig rings of 10 mm i.d., 15 mm o.d. and 20 mm length. The reactors were operated at 35$\circ$C and the hydraulic retention time(HRT) was maintained 24 hours. The synthetic wastewater composed of glucose and phenol as major components was fed into the reactor in a continuous mode with incereasing phenol concentration. In addition, the nutrient trace metals($Na^+, Mg^{2+}, Ca^{2+}, PO_4^{3-}, NH_4^+, Co^{2+}, Fe^{2+}$ etc.) were added for growing anaerobes. The phenol concentration of the effluent, the overall gas production, the composition of product gas, the efficiency of COD reduction and the duration of acclimation period were measured to determine the performance of the anaerobic wastewater treatment system as the phenol concentration of the influent was increased from 600 to 2400 mg//l. Successfully stable biodegradation of phenol could be achieved with the anaerobic treatment system from 600 to 1, 800 mg/l of the influent phenol concentration. The upper level of influent phenol loading was high enough to meet most of the practical requirement. The duration of acclimation increased with the phenol loading. At steady state of the influent phenol concentration of 1800 mg/l, the treatment performance indicated the phenol reduction efficiency of 99%, the COD reduction efficiency of 99% and the gas production rate of 37 l/day. At the influent phenol concentration of 2400 mg/l, however, the operation of the treatment system was noted unstable. While the concentration of methane in biogas decreased with increasing the influent phenol loading, the carbon dioxide was increased. However, the concentration of hydrogen was varied negligibly. The concentration of methane was high enough to be used as a fuel. As a result, it is suggested that anaerobic phenol wastewater treament was economical in the sense of energy recovery and wastewater treatment.

• 미생물학회지
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• 제54권1호
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• pp.53-59
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• 2018

이 실험은 제주도내 양식장으로부터 유입수와 방출수의 다제내성(MDR)을 가진 Vibrio 균의 plasmid profiling을 위해 진행하였다. Plasmid profiling을 위해 사용한 다제내성을 가진 균주는 디스크 확산법을 통해 확인하였고, 유입수와 방출수으로부터 각각 150개의 Vibrio 균주를 분리하였다. 모든 다제내성 균주를 대상으로 plasmid profiling을 실시하였으며, 유입수와 비교하여 방출수에서 많은Vibrio 균이 열거되었다(유입수 39%, 방출수 61%). 방출수에서는 neomycin, sulfamethoxazole, amoxicillin 및 oxytetracycline의 내성을 가진 균주가 유의적으로 많은 것으로 확인되었고, 대조적으로 Vibrio 균주는 florfenicol, chloramphenicol, ciprofloxacin 및 nalidixic acid에 더 민감한 것으로 확인이 되었다. 99종의 다제내성 균주(유입수 39종과 방출수 60종) 중에서 총 58종(유입수 38종과 방출수 20종)이 1.7 kb에서 10 kb 이상의 플라스미드를 가지고 있는 것을 확인하였으며 플라스미드 크기마다 19가지의 다른 다제내성 패턴을 보였다. 6종의 유입수와 4종의 방출수에서 다제내성 균주는 특이적인 plasmid profile이 확인되었다. 방출수 샘플은 보다 많은 플라스미드를 가진 다제내성 Vibrio 균주와 다양한 plasmid profile들과 다제내성 패턴을 가지고 있었고 이는 양식장의 저장탱크가 항생제내성 유전자의 저장소 역할을 할 수 있다는 점을 시사한다. 양식장의 방출수에서 plasmid를 가진 다제내성 Vibrio 균주의 존재는 항생제 내성 유전자의 전파에 기여할 수 있으며 이로 인해 인간의 건강을 위협할 수 있다.

• 생태와환경
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• 제36권2호통권103호
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• pp.172-180
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• 2003

평택호와 주요 유입하천에서 2000년 3월부터 12월까지 수질의 생몰학적 평가를 위해 남조류 Microcystis aeruginosa의 조류생장잠재력측정 (AGPT)을 계절에 따라 4회 측정하였다. 평택호와 유입하천에서 AGPT의 범위와 평균값은 각각 0${\sim}$463mg dw/1, 90 mg dw/l이었다. 유입하천 중 AGPT의 평균값은 황구지천에서 343 mg dw/1로서 가장 높았고 서정천, 성환천, 오산천과 진위천 및 안성천에서 각각 158, 66, 29및 21mg dw/1 순으로 감소하였다. 평택호에서 AGPT값은 0${\sim}$138 mg dw/1 범위(평균 54 mg dw/1)였으며 대체적으로 유입하천과 근접된상류에서 높고 하류로 갈수록 감소하는 양상을 보였으나 하계에 유입량이 급증한 직후에는 상류에서 남조류의 대발생 (130${\mu}g$ chl-a/l)으로 인해 오히려 하류가 2배정도 높았다. 평택호와 유입하천의 수질은 갈수기에 더욱 악화되었고 이 시기에 AGPT값도 컸다. AGPT는 영양염 중 P와 상관(r=0.999, p⁢0.001)이 가장 높아 조류의 생장에 P의 영향이 가장 큰 것으로 추정되었다. 평택호 유역에서 AGPT는 시공간적으로 변화 폭이 컸고 유입하천의 영양염 수준과 밀접한 관련성이 있었다. AGPT에 의한 수질상태는 과영양 수준 (>20 mg dw/1)으로 평가되어 이에 대한 수환경 관리가 중요하였다. AGPT는 조류 생장에 대한 제한영양염 판정 뿐만 아니라, 수중 fertility를 평가함에 있어 유용하였다.

• 한국환경복원기술학회지
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• 제13권3호
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• pp.23-35
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• 2010

A Sustainable Structured wetland Biotop (SSB) system was constructed on the floodplain of Kyungan stream in December, 2006. It purifies polluted water of Keumeo stream which flows into the stream. Water were sampled once a month at inlet and outlet from December, 2007 to December, 2008. $BOD_5$, SS, T-N and T-P were analyzed. Plant and fish species of the system were monitored twice during the period. Average influent and effluent BOD5 concentration was 6.2 and 2.2 mg/L, respectively and BOD5 removal was 50.8%. SS concentration of influent and effluent was averaged 10.1mg/L and 1.5mg/L, respectively and SS abatement amounted to 77.0%. Average influent and effluent T-N concentration was 4.9mg/L and 2.9 mg/L, respectively and T-N retention was 50.8%. T-P concentration of influent and effluent was averaged 0.386mg/L and 0.107mg/L, respectively and T-P removal amounted to 77.0%. Twenty two plant species were naturally introduced into the system, however, they didn't make up a significant portion of the plant populations compared with the planted species. Dominant plant species were in the following order; Phragmites communis > Typha latifolia > Iris pseudoacorus > Persicaria thunbergii. Five families and 15 species of fish were observed in the system including Chinese minnow (Moroco oxycephalus) which inhabits in clean water. Six more fish species were monitored in the system compared with ones living in Kyungan stream. Amphibia and reptiles accounted for 11 species of 4 orders and 7 families including Korean Salamander (Hynobius leechi) which also lives in cleanwater.

• 한국환경복원기술학회지
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• 제4권4호
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• pp.46-55
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• 2001

Analysis of fish farm influences on stream water quality may provide basic informations on watershed management to reduce environmental impact due to fish farm development and to conserve stream water quality in forested watershed area. In this research stream water qualities around Mt. Baegun area were monitored seasonally for three years. Due to the increase of pH in effluent water from the fish farm it was believed that alkalization of stream water can be accelerated by large scale development of fish farms in the forested watershed area. As a result of regression analyses, the linear equation of pH of influent and effluent water of fish farm was, pH of effluent water of fish farm = $0.6234{\times}pH$ of influent water of fish farm + 2.6263. Also, the linear equation of electrical conductivity of influent and effluent water of fish farm was electrical conductivity of effluent water of fish farm = $1.7275{\times}$electrical conductivity of influent water of fish farm - 14.007. Negative effects on stream water quality were observed by indications of increase in electrical conductivity and water temperature of effluent water from the fish farm. Decreases in physicochemical indices such as the amount of dissolved oxygen, total amount of cation and total amount of anion in effluent water from the fish farm were also negative aspects in downstream ecology. It is recommended that water purification system as well as environmentally-friendly fish farm design should be incorporated to large scale fish farm development plan in forested watershed area.

• 한국물환경학회지
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• 제23권5호
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• pp.607-612
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• 2007

In this study, we investigated the variations of the kinetic coefficients and Chemical Oxygen Demand (COD), N and P mass used for assimilation of a sequencing batch reactor (SBR) system with the variation of SRTs; SRTs of 7.5, 10.0, 12.5, 15.0 and 20.0 days were tested in one cycle of SBR operation to determine the optimum conditions for the operation of the SBR and estimate its COD, nitrogen and phosphorus removal efficiencies. The SBR system was operated under the conditions as follows: an operation time of 6 hours per cycle, a hydraulic retention time (HRT) of 12 hours, an influent COD loading of $0.4kg/m^3/day$, and an influent nitrogen loading of $0.068kgT-N/m^3/day$. The yield coefficient (Y) and decay rate coefficient ($k_d$) were estimated to be 0.4198 kgMLVSS/kgCOD and $0.0107day^{-1}$ by calculating the removal rate of substrate according to the variation of SRT. Considering total nitrogen amount removed by sludge waste process, eliminated by denitrification, and in clarified water effluent with reference to 150 mg/cycle of influent nitrogen amount, the percentage of nitrogen mass balance from the ratio of the nitrogen amount in effluent (N output) to that in influent (N input) for Runs 1~5 were 95.5, 97.0, 95.5, 99.5, and 95.5%, respectively, which is well accounted for, with mass balances close to 100%.

• 상하수도학회지
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• 제27권4호
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• pp.489-494
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• 2013

Effects of operating parameters such as hydraulic retention time(HRT), recycle ratio and influent COD concentration on the performance of a continuous flow microbial fuel cell(MFC) were investigated. Decrease of HRT improved mass transfer of substrate to electrogenic microorganisms, therefore resulting in increased electrode voltage and power generation of MFC. Increase of HRT promoted COD removal by elongating retention time for COD removal in MFC. Recycling of effluent increased the COD removal and coulombic efficiencies by returning suspended microorganisms into MFC. Increase of influent COD enhanced COD removal due to the improved mass transfer of substrate. Decrease of coulombic efficiency by the increase of the HRT and influent COD concentration indicated that they enhanced the activities of fermentative bacteria.

• 상하수도학회지
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• 제19권6호
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• pp.791-799
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• 2005

The phased isolation intra-clarifier ditch system used in this study is a simplified novel process enhancing simultaneous removal of biological nitrogen and phosphorus in municipal wastewater in terms of elimination of additional pre-anaerobic reactor, external clarifier, recycle of sludge, and nitrified effluent recirculation by employing intrachannel clarifier. Laboratory-scale phased isolation ditch system was used to assess the treatability on municipal wastewater. When the system was operated at the HRTs of 6~12hours, SRTs of 9~31days, and cycle times of 2~8hours, the system showed removals of BOD, TN, and TP as high as 88~97%, 70~84%, and 65~90%, respectively. The rainfall in Korea is generally concentrated in summer because of site-specific characteristics. Especially, the wet season has set in on June to August. In combined sewers, seasonal variations are primarily a function of the amount of stormwater that enters the system. In order to investigate the effect of hydraulic shock loading on system performance, the laboratory-scale system was operated at an HRT of 6hours (two times of influent flowrate) during two cycles (8hours). The system performance slightly decreased by increasing of influent flowrate and decreasing of system HRT. Nitrification efficiency and TN removal were slightly decreased by increasing of influent flowrate (decreasing of system HRT), whereas, the denitrification was not affected by hydraulic shock loading. However, the higher system performance could be achieved again after four cycles. Thus, the phased isolation technology for enhanced biological nutrient removal in medium- and small-scale wastewater treatment plants suffering fluctuation of influent quality and flowrate.

• 한국물환경학회지
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• 제20권6호
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• pp.571-576
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• 2004

Since anaerobic/anoxic/oxic process, which is a typical mainstream biological nitrogen and phosphorus removal process, utilizes influent organic matter as an external carbon source for phosphorus release in anaerobic or anoxic stage, influent COD/T-P ratio gives a strong influence on performance of phosphorus removal process. In this study, a bench scale experiment was carried out for SBR process to investigate nitrogen and phosphorus removal at various influent COD/T-P ratio and nitrate loadings of 23~73 and 1.6~14.3g $NO_3{^-}-N/kg$ MLSS, respectively. The phosphorus release and excess uptake in anoxic condition were very active at influent COD/T-P ratios of 44 and 73. However, its release and uptake was not obviously observed at COD/T-P ratio of 23. Consequently, phosphorus removal efficiency was decreased. In addition, the phosphorus release and uptake rate in anoxic condition increased as the nitrate loading decreased. Specific denitrification rate had significantly high correlation with organic materials and nitrate loadings of the anoxic phase too. The rate of phosphorus release and uptake in the anoxic condition were $0.08{\sim}0.94kg\;S-P/kg\;MLSS{\cdot}d$ and $0.012{\sim}0.1kg\;S-P/kg\;MLSS{\cdot}d$, respectively.

• 한국환경과학회지
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• 제16권11호
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• pp.1271-1277
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• 2007

This study was conducted to investigate the ratios of phosphorus release to COD uptake, phosphorus release to nitrate removal, and phosphorus uptake to phosphorus release by DNPAOs(denitrifying phosphate accumulating organisms). In case $I{\sim}IV$, influent 1 were fed with synthetic wastewater with influent 2 $NO_3^--N$ injection to anoxic zone and the case V were fed with municipal wastewater with side stream oxic zone instead of influent 2 $NO_3^--N$ injection. As a result, the ratio of phosphorus release to carbon uptake was increased in accordance with nitrate supply. The DNPAOs simultaneously took up phosphate and removed nitrate from the anoxic reactor. In case $I{\sim}IV$, with above 20 mg/L of sufficient $NO_3^--N$ supply, phosphate was taken up excessively by the DNPAOs in anoxic condition. The large amount of both uptake and release of phosphorus occurred above 20 mg/L of nitrate supply, achieving the ratio of phosphorus uptake to phosphorus release to be 1.05. In case V, phosphate luxury uptake was not occurred in system due to 6.98 mg/L of insufficient $NO_3^--N$ supply and the ratio of phosphorus uptake to phosphorus release was 0.98. Consequently, if nitrate as the electron acceptor was sufficient in anoxic zone, the ratio was found to be high.