• 대한토목학회논문집
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• 제26권4B호
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• pp.433-437
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• 2006

최근, 활성 슬러지 공법에 대한 수학적 모델링은 폐수처리장의 설계와 운영에 있어서 매우 중요한 인자로 인식되고 있다. 그럼에도 불구하고, BNR 공정에서 미생물의 성장 및 호흡과 관련한 내 외부 기질의 이용 경로에 관한 정보는 여전히 부족한 실정이다. 본 논문에서는 ASM No.3와 비교되는 새로운 개념의 활성슬러지 모델을 제시하고자 한다. 미생물의 단계별 성장이론에 근거한 이 모텔의 구조는 호기성 저장, 내부저장물질(ISCs; Intercellular Storage Compounds)과 외부기질 활용에 따른 미생물의 성장, 내생호흡과 내부저장물질을 이용한 호기성 호흡 등 5 단계로 구성되어 있다. 단계적 성장모델에 기초한 예측결과는 산소이용율(OUR)과 TCOD에 의한 실험결과에 있어 ASM No.3의 결과보다 더욱 일치함을 나타냈다.

• 상하수도학회지
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• 제14권1호
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• pp.62-75
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• 2000

Most of biological treatment to remove contaminants in municipal wastewater have been conducted by activated sludge process. But, the process have several probIems such as enormous site needed for construction of treatment facilities, unstable treatment due to limited ability to control load fluctuation, frequent sludge bulking and appearance of lots of surplus sludge. In this study, the experiments were performed through submerging biofilm of PEPP media in existing aeration tank with raw water from municipal wastewater treatment plant and then submerging PVDC and PEPP media, different from shape and chemical peculiarity in anoxic reactor. Throughout the experience, nutrient removal efficiency according to HRT, nitrogen phosphorous removal efficiency, behavior of nitrogen and dewatering efficiency have been compared and analysed with those of activated sludge process. As the results, BOD removal efficiency according to BOD volumetric load and F/M ratio was not found any differency in two processes, but was decreased below 90% as going along the condition of high load in activated sludge process. Kinetic coefficient was $K_{max}=1.162day^{-1}$, $K_s=53.77mg/L$, $Y=0.166mgVSS/mgBOD_{rem}$. and $K_d=0.019day^{-1}$. It was found that the removal efficiency, even though in aerobic condition, in biofilm process equipped anoxic reactor was higher than the one in activated sludge process within the range of 70~80%, and became better as HRT increased. Phosphorous removal efficiency was not found any differency in two processes. In biofilm process, treament efficiency even in conditions of high load was not decreased, because the biomass concentration could be maintained in high condition compared with activated sludge process. As HRT increased, suspended and attached biomass was increased and the other hand, F/M ratio was decreased as biomass' increasing. Biomass thickness was increased. from $10.43{\mu}m$ to $10.55{\mu}m$ as HRT increased and density of biomass within $40.79{\sim}41.16mg/cm^2$. The results also present that the dewatering efficiency of sludge generated in biofilm process was higher than in activated sludge process, and became better as HRT increased.

• 상하수도학회지
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• 제32권6호
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• pp.535-550
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• 2018

Total organic carbon (TOC) will replace chemical oxygen demand ($COD_{Mn}$) as an effluent water quality standard in public sewage treatment works (PSTWs) from 2021 in Korea. To ensure effective control of TOC in the effluent, investigation was carried out into TOC levels and sewage treatment operation factors in five target PSTWs using anaerobic-anoxic-aerobic ($A_2O$) processes, media, membrane, and sequencing batch reactor (SBR) technologies. TOC removal efficiencies appeared to be 93-96% on average. As a fraction of TOC, biodegradable dissolved organic carbon (BDOC) was reduced from 64% in the influent to 9% in the effluent in these PSTWs. During the investigation, biological treatment processes were applied flexibly for operation factors such as HRT, SRT, MLSS, F/M ratios and BOD volume loads, based on the influent characteristics and design conditions. As a result, we suggest efficient operating conditions in PSTWs by evaluating relationships between TOC removal and operation factors.

• 한국물환경학회지
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• 제21권4호
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• pp.337-346
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• 2005

An MSBR using a membrane for not only filtration but also aeration (MA-MSBR) was designed to reduce membrane fouling and to enhance water quality, and compared with an MSBR using a membrane for only filtration (BA-MSBR). COD removal efficiency of the MA-MSBR was similar to that of the BA-MSBR, but membrane performance of the MA-MSBR was better than that of the BA-MSBR. The MA-MSBR had more small particles in mixed liquor, so the specific cake resistance of flocs in the MA-MSBR was higher than that in the BA-MSBR. However, in the aerobic reaction step of the MA-MSBR, air went through membrane pores and out of the membrane surface, so cake layers on the membrane surface and a portion of organics adsorbed on membrane pores could be removed periodically. Therefore, cake resistance, $R_c$, and fouling resistance by adsorption and blocking, $R_f$, for the MA-MSBR increased more slowly than those for the BA-MSBR. Additionally, in order to compare the energy efficiency for two MSBRs, oxygen transfer efficiency and power to supply air into the reactor by a membrane module and a bubble stone diffuser were measured using deionized water. From these measurements, the transferred oxygen amount per unit energy was calculated, resulting that of MA-MSBR was slightly higher than that of BA-MSBR.

• 한국축산시설환경학회지
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• 제12권2호
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• pp.85-94
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• 2006

The effects of turning frequency of in-vessel composting on ammonia emissions during composting of separated solids from swine slurry/sawdust mixtures and performance of biofiltration using the chicken manure compost were investigated. Separated solids from swine manure amended with sawdust was composted in a 226 L laboratory-scale in-vessel reactors under various turning frequency and continuous airflow (0.6 L/min.kg.dm) for three weeks. Three laboratory-scale manure compost biofilters were built to treat effluent gas from the composting of separated solid from swine manure amened with sawdust process. These experiments were continued over a period of three weeks. The composting of separated solid swine manure amended with sawdust and manure compost biofiltration system were evaluated to determine the turning frequency type that would be adequate for the rate of decomposition and compost odour reduction. The compost odour cleaning was measured based on ammonia gas concentration before and after passing through the manure compost biofilter. The average ammonia odor reduction in the manure compost biofilter was 96.9 % at R1 (no turning), 99.4 % at R2(once a day turning) and 89.0 % at R3(twice a day turning), respectively. The efficiency of ammonia reduction was mainly influenced by the turning frequency.

• Journal of Microbiology and Biotechnology
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• 제14권3호
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• pp.639-642
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• 2004

The pH as a control parameter for oxidation-reduction potential (ORP) was investigated through the denitrification by Ochrobactrum anthropi SY509 under non-growing condition. The optimal pH of nitrate reductase was 7.0, and the minimal ORP level was －250 mV for the denitrification under aerobic condition. In the case of anaerobic condition, the optimal pHs of nitrate and nitrite reductase were shifted to 10.0 and 9.0, respectively, and the minimal ORP levels of nitrate and nitrite reductase were decreased to －370 mV and －340mV, respectively. In the case of alkaline pH and anaerobic condition, the denitrification efficiency of nitrate was increased up to about 2-fold over that of neutral pH and anaerobic condition. Therefore, the combined control of pH and ORP in the anaerobic condition is shown to be an important parameter in the biological denitrification process.

• Environmental Analysis Health and Toxicology
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• 제6권3_4호
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• pp.133-141
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• 1991

Vermistabilization is the stabilization of organic wastes using earthworms. The worms maintain aerobic conditions in the waste, accelerating and enhancing the biological decomposition of the waste. This study was carried out to find out fundamental factors affecting the performance of the process such as temperature, moisture content and pH condition of nightsoil sludge, and to evaluate the worms excreta (casting) as fertilizer. The results could be summarized as follows; the optimum range of temperature was observed 10~3$0^{\circ}C$ while survival rate of eathworm decreased rapidly at 35$^{\circ}C$ within 6 days and death occurred at 5$^{\circ}C$. Those of moisture content and pH condition were 50~70% and 5~8, respectively. Earthworms were revealed to change the composition of N in nightsoil sludge consisting of$NH_3$-N (71%), $NO_2$-N (2%) and $NO_3$-N (27%) into that $NH_3$-N (24%), $NO_2$-N (1%), $NO_3$-N (75%) in earthworm excreta, respectively The concentrations of NH$_3$and H$_2$S gas in pig manure were reduced by 59.2% and 45.2% in case of mixing pig manure with casting.

• Environmental Engineering Research
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• 제25권2호
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• pp.212-221
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• 2020

This work discusses the palm oil mill processing carried out at Jugra Palm Oil Mill Sdn Bhd, situated at Selangor, Malaysia with the capacity of 45-t fresh fruit bunch (FFB)/h. Typically, oil palm residues and palm oil mill effluent (POME) from FFB are generated while processing. Prior to discharge, POME should be treated to remove pollutants in the effluent. As such, the performances of anaerobic and aerobic ponds were assessed in this study to determine temperature, pH, biological oxygen demand (BOD), sludge volume index (SVI), and dissolved oxygen (DO). From the experiments, mesophilic temperature due to better process stability was applied in anaerobic ponds. The pH results displayed a fluctuating trend between lower control limit and upper control limit, and, the pH value increased from one pond to another. The final discharge BOD and SVI appeared to be lower than 100 mg/L and 10 mL/L indicating low degree of pollution and good settling ability for biomass/solid. DO was close to normal, mostly below 2 mg/L. The experimental outcomes revealed the effective treatability of POME in adherence to the standard regulation, which is the priority for environmental sustainability within this industry domain.

• 정신신체의학
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• 제15권2호
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• pp.65-72
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• 2007

정신과에 내원하는 환자들 중에서 피로를 호소하는 환자들의 비율이 높으며, 만성적인 피로감을 호소하는 환자들에서 다른 우울증과 같은 정신과질환이 공존하는 경우도 많다. 환자들은 많은 괴로움을 호소하나, 기저의 임상상태의 종류와 심각도에 대해서는 비특이적이므로 실제로는 임상가에 의해서 무시되는 경우가 많으며, 그 중요성이 과소평가되는 경우가 많아서, 적절한 처치를 받지 못하고 삶의 질에도 많은 영향을 받게 된다. 피로는 말초와 중추신경계 둘 다에서 영향을 받는 다차원적인 현상으로 이해하여야 한다. 환자가 호소하는 피로증상에 대해서 좀 더 적극적으로 조절하기 위한 여러 약물학적 및 비약물학적 접근법들이 시도되고 있다.

• Journal of Microbiology and Biotechnology
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• 제20권3호
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• pp.594-601
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• 2010

Azotobacter chroococcum H23 (CECT 4435), Azotobacter vinelandii UWD, and Azotobacter vinelandii (ATCC 12837), members of the family Pseudomonadaceae, were used to evaluate their capacity to grow and accumulate polyhydroxyalkanoates (PHAs) using two-phase olive mill wastewater (TPOMW, alpeorujo) diluted at different concentrations as the sole carbon source. The PHAs amounts (g/l) increased clearly when the TPOMW samples were previously digested under anaerobic conditions. The MNR analysis demonstrated that the bacterial strains formed only homopolymers containing $\beta$-hydroxybutyrate, either when grown in diluted TPOMW medium or diluted anaerobically digested TPOMW medium. COD values of the diluted anaerobically digested waste were measured before and after the aerobic PHA-storing phase, and a clear reduction (72%) was recorded after 72 h of incubation. The results obtained in this study suggest the perspectives for using these bacterial strains to produce PHAs from TPOMW, and in parallel, contribute efficiently to the bioremediation of this waste. This fact seems essential if bioplastics are to become competitive products.