• Title/Summary/Keyword: Anoxic/Oxic(A/O) process

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A Study on the Removal of Nitrogen and Phosphorus Depending on Existence of Cilia Media in Sewage in Anaerobic-Anoxic-Oxic Process ($A_2O$공정에서의 섬모상 담체 사용 유무에 따른 하수의 질소 . 인 제거에 관한 연구)

  • 박태진;이정민;송경석;조일형;김영규;정문호
    • Journal of Environmental Health Sciences
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    • v.26 no.3
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    • pp.69-75
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    • 2000
  • This study was carried out to investigate the removal of nitrogen and phosphorus in municipal sewage according to the variation of volumetric ratio in the reactor. It also was performed to provide basic data necessary to the development and improvement of the process which is Anaerobic-Anoxic-Oxic(A2O). In the removal of BOD and COD, the best efficiency of the process showed in the condition of using the media, 1Q of internal recycle rate and 1:3:2 of the volumetric ratio in Anaerobic-Anoxic-Oxic process. In most cases, nitrogen and phosphorus removal efficiency of the process using the cilia media was superior to that of the process which didn't use the media. In the removal of T-N and T-P, the best efficiency of the process showed in the condition of using the media, 1Q of internal recycle rate and 1:3:2 of the volumetric ratio in Anaerobic-Anoxic-Oxic process.

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Characteristics of Organics and Nitrogen Removal with the Recycle Ratio in Anoxic / Oxic Packed Bed Process (충전탑형 무산소/호기 공정에서 반송비에 따른 유기물 및 질소 제거 특성)

  • 선용호
    • Journal of Environmental Science International
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    • v.11 no.12
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    • pp.1261-1265
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    • 2002
  • This study was focused on the investigation of the characteristics of organics and nitrogen removal with the recycle ratio in anoxic/oxic(A/O) packed bed process that consisted of the anoxic reactor and the aerobic reactor. As increasing the recycle ratio by 0.5, 1.0, 2.0, the COD removal efficiency increased by 94.0%, 98.5%, 98.8% respectively. The aerobic reactor showed the perfect nitrification efficiency by 98.5%, 99.2%, 98.0% respectively. The T-N removal efficiency with the recycle ratio, increased by 56%, 67%, 70% respectively. As increasing the recycle ratio by 0.5, 1.0, 2.0, T-P removal efficiency decreased by 62.1%, 57.4%, 51.3% respectively. The process by releasing the stored phosphorus in the anoxic reactor and uptaking the excess phosphorus in the aerobic reactor, occurred well comparatively when recycle ratio is 0.5. But this process did not occur when the recycle ratio is 1.0 and 2.0. And optimum pH of nitrification was about 6~7 and alkalinity decreased as nitrification rate increased. As increasing the recycle ratio in the anoxic reactor, DO concentration and ORP increased.

Comparison of Anoxic/Oxic Membrane Bioreactor - Reverse Osmosis and Activated Sludge Process-Microfiltration-Reverse Osmosis Process for Advanced Treatment of Wastewater (폐수의 고도처리를 위한 무산소/호기형 분리막생물반응조 - 역삼투 공정과 활성슬러지공정 - 정밀여과 - 역삼투 공정의 비교)

  • Roh, Sung-Hee;Kim, Sun-Il;Quan, Hong-hua;Song, Yon-Ho
    • Applied Chemistry for Engineering
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    • v.17 no.5
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    • pp.521-526
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    • 2006
  • A membrane bioreactor (MBR) is an effective tool for wastewater treatment with recycling. MBR process has several advantages over conventional activated sludge process (ASP); reliability, compactness, and quality of treated water. The resulting high-quality and disinfected effluents suggest that MBR process can be suitable for the reused and recycling of wastewater. An anoxic/oxic (A/O) type MBR was applied to simultaneous removal of organics and nutrients in sewage. At first, the efficiency of submerged MBR process was investigated using a hollow fiber microfiltration membrane with a constant flux of $10.2L/m^2{\cdot}h$ at each solids retention time (SRT). Results showed that protein/carbohydrate (P/C) ratio increased and total extracellular polymeric substances (EPS) remained constant with SRT increased. Secondly, A/O type MBR with a reverse osmosis (RO) membrane was employed to treat the municipal wastewater. The performance of A/O type MBR-RO process is better for the treatment of organics and nutrients than ASP-MF-RO process in terms of consistent effluents quality.

Improvement of the Advanced Treatment for Nitrogen Removal of Acrylic Fiber Wastewater (아크릴섬유 폐수의 생물학적 질소제거공정의 개선)

  • Lee, Chan-Won;Cho, In-Sung;Lim, Kyeong-Won
    • Journal of Environmental Science International
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    • v.15 no.5
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    • pp.439-446
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    • 2006
  • The effluent discharge standards of industrial wastewater has become more stringent since 2003. Many industrial wastewater treatment plants has been upgraded to advanced treatment facilities. There are high concentrations of nitrate(>200 mg/L) and ammonium(>50 mg/L) nitrogen in the acrylic fiber wastewater of H textile Co. Wastewater from acrylic fiber industry containing acrylonitrile, which may affect the subsequent biological treatment process. Manufacturing of acrylic fiber also produces shock loadings. Excessive acrylonitrile and polymer debris produced in the polymerization process was screened, coagulated with CaO and settled down. A preaeration system was added to treat this high pH effluent to remove volatile organic compound and ammonia nitrogen by the air stripping effect. it was found that nitrification rate was not sufficient in the Anoxic/Oxic(AO) process. One denitrification tank was converted to nitrification reactor to extend HRT of nitrification. Nitrification rate of ammonia nitrogen was promoted from 32% to 67% by this modification and effluent nitrogen concentration was well satisfied with the effluent standards since then.

Comparison of Phosphorus and Nitrogen Removal Characteristics between A2/O and Modified Phostrip Processes (A2/O공정과 수정 Phostrip공정과의 질소 및 인제거 특성비교)

  • Kim, Kwang-Soo;Kim, I-Tai
    • Journal of Korean Society on Water Environment
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    • v.21 no.6
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    • pp.664-668
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    • 2005
  • An experimental study for the comparison of nitrogen and phosphorus removal efficiencies between $A^2/O$ and modified Phostrip (M-Phostrip process) were carried out with bench-scale reactors. In case of nitrogen removal efficiencies both of processes showed similar ones when influent organic loadings were high. However, M-phostrip process was more effective than $A^2/O$ at low organic loadings. This is why M-phostrip process consumes the whole mass of influent organics as a carbon sources for denitrification in anoxic reactor but the anoxic reactor of $A^2/O$ process utilizes the residual carbon followed by consumming a part of influent carbon for phosphorus release in anaerobic reactor. $A^2/O$ process required the influent COD/T-P and COD/TKN ratios were more than 56 and 10, respectively, to take place the phosphorus release in anaerobic process and phosphorus uptake in oxic process. However, the luxury uptake of phosphorus in M-phostrip process was not affected by influent COD/T-P and COD/TKN ratios and the adverse effect of nitrate in return sludge introduced to the p-stripper from the 2nd clarifier was not significant due to the configurational advantage of the p-stripper.

The Nitrogen Removal of Municipal Wastewater with HRT using CNR Process (CNR공법의 체류시간에 따른 도시하수의 질소제거)

  • 김영규;양익배;김인배
    • Journal of Environmental Health Sciences
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    • v.26 no.3
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    • pp.98-102
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    • 2000
  • The aim of this study was to evaluate on the removal effect of total nitrogen in municipal wastewater by decreasing hydraulic retention time(HRT) from 6 hour to 4 hour on CNR process. CNR-A(Cilia Nutrient Removal) is the process combining A2/O process with cilium media of H2L corporation. The removal efficiencies for T-N were 63.1% in A-1 reactor, and 73.5% in A-2 reactor and 77.0% in A-3 reactor. The specific nitrification(g-NH3-N/g-MLVSS.d) of Oxic in CNR-A process was 0.07-0.32. The specific denitrification in Anoxic and the specific nitrification inOxic was higher in HRT 4 hour because of optimum F/M ratio.

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The Study on Evaluating Performances of Lab Sacle-Advanced $A_{2}O$ with Changing System Using Biofilm Process (생물막 담체를 이용한 실험실 규모 $A_{2}O$공법의 시스템 변형에 따른 고도처리 성능 평가에 관한 연구)

  • Kim, Min-Sik;Kang, Gu-Young
    • Journal of Korean Society of Water and Wastewater
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    • v.26 no.2
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    • pp.209-218
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    • 2012
  • Recently, as reinforced water quality standards for wastewater has been announced, more efficient and more powerful wastewater treatment processes are required rather than the existing activated sludge process. In order to meet this demands, we evaluate Task 1-4 about lab scale $A_{2}O$ process using biofilm media. Task 1, 2, and 3 use 'Module A' which has 4 partitions (Anoxic/Anerobic/Oxic/Oxic). Task 4 uses 'Module B' which has 2 partitions including a denitrification reactor with an Inclined plug flow reactor (IPFR) and a nitrification reactor with biofilm media. The denitrification reactor of Module B is designed to be upward flow using IPFR. The result of evaluating at each Task has shown that attached growth system has better capacity of removal efficiency for organic matter and nitrogen with the exception of phosphorus. Task 4 which has the most outstanding removal efficiency has 90.5% of $BOD_{5}$ removal efficiency, 97.8% of ${NH_4}^{+}-N$ removal efficiency, 65% of T-N removal efficiency and 92% of T-P removal efficiency with additional chemical phosphorus removal system operated at HRT 9hr, Qi:Qir 1:2, and BOD/T-N ratio 2.7.

Nitrogen removal characteristics of pigment wastewater using PAC-A/O process (PAC-A/O 공정을 이용한 안료폐수의 질소 제거 특성)

  • Jeong, Jongsik
    • Journal of Korean Society of Water and Wastewater
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    • v.32 no.1
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    • pp.19-25
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    • 2018
  • The objectives of this study were to evaluate the removal characteristics of total nitrogen, the influence factor of denitrification and the optimum operating condition in the pigment wastewater treatment using PAC-A/O process. The operating conditions of PAC-A/O process were mean BOD volumetric loading $0.86kgBOD/m^3/day$, mean F/M ratio 0.072~0.13 kgBOD/kgMLVSS/day and mean C/N ratio 3.47, respectively. The conditions of anoxic process in the field plant test were mean pH 8.3~8.7 and mean temperature $34.1{\sim}44.0^{\circ}C$. The ORP bending point knee was eventually appeared in the ORP -107 mV and $NO_3{^-}-N$ removal efficiency was increased according to the ORP decrease. In the ORP -107 mV below condition, the removal efficiency of T-N and $NO_3{^-}-N$ was 92.3~95.0% and 98.5~99.7%. Denitrification rate was calculated to be 1.581~1.791 mg $NO_3{^-}-N/gMLSS/hr$. The experimental results showed that the ORP control in the PAC-A/O process could be an effective method for treatment of pigment wastewater.

Investigation of Operating Parameters on UCT Process for the Purpose of Nitrogen Removal Using Computer Simulation (하수의 질소제거시 컴퓨터 시뮬레이션을 이용한 UCT(University of Cape Town) 공정의 운영인자 검토)

  • 김병군;서인석;이해군;김창원
    • Journal of environmental and Sanitary engineering
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    • v.13 no.2
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    • pp.66-75
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    • 1998
  • The computer simulation model was used to forecast the concentrations of COD$_{cr}$, NH$_{4}$$^{+}$-N and NO$_{3}$$^{-}$-N in each reactors. In the biological wastewater treatment system, the computer simulation model was used to observe the behavior of pollutants especially. In this research, effect of SRT, feeding pattern and recirculation rate on UCT(University of Cape Town) process was evaluated by computer simulation model. T-N removal was affected to the SRT. SRT for effective T-N removal was 15 days or longer. Feeding pattern in UCT process was affected to the T-N removal. Feeding pattern which 100% loading to the first reactor was most effective for T-N removal. The effect of recirculation rate was clear for T-N removal. The recirculation from anoxic reactor to anaerobic reactor was not need but the recirculation from oxic reactor to anoxic reactor was need. In aspect of nitrogen removal efficiency, A/O process was higher than UCT process.

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Modeling of Recycling Oxic and Anoxic Treatment System for Swine Wastewater Using Neural Networks

  • Park, Jung-Hye;Sohn, Jun-Il;Yang, Hyun-Sook;Chung, Young-Ryun;Lee, Minho;Koh, Sung-Cheol
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.5 no.5
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    • pp.355-361
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    • 2000
  • A recycling reactor system operated under sequential anoxic and oxic conditions for the treatment of swine wastewater has been developed, in which piggery slurry is fermentatively and aerobically treated and then part of the effluent is recycled to the pigsty. This system significantly removes offensive smells (at both the pigsty and the treatment plant), BOD and others, and may be cost effective for small-scale farms. The most dominant heterotrophic were, in order, Alcaligenes faecalis, Brevundimonas diminuta and Streptococcus sp., while lactic acid bacteria were dominantly observed in the anoxic tank. We propose a novel monitoring system for a recycling piggery slurry treatment system through the use of neural networks. In this study, we tried to model the treatment process for each tank in the system (influent, fermentation, aeration, first sedimentation and fourth sedimentation tanks) based upon the population densities of the heterotrophic and lactic acid bacteria. Principal component analysis(PCA) was first applied to identify a relationship between input and output. The input would be microbial densities and the treatment parameters, such as population densities of heterotrophic and lactic acid bacteria, suspended solids(SS), COD, NH$_4$(sup)+-N, ortho-phosphorus (o-P), and total-phosphorus (T-P). then multi-layer neural networks were employed to model the treatment process for each tank. PCA filtration of the input data as microbial densities was found to facilitate the modeling procedure for the system monitoring even with a relatively lower number of imput. Neural network independently trained for each treatment tank and their subsequent combined data analysis allowed a successful prediction of the treatment system for at least two days.

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