• Title/Summary/Keyword: activated sludge system

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Utilization of Ready-mixed Concrete Recycling Water Mixed with Hot-rolled Slag Containing C12A7 and Application Characteristics of Cement Mortar (C12A7을 함유한 열연슬래그를 혼입한 레미콘 회수수 활용 및 시멘트 모르타르의 적용 특성)

  • Kim, Young-Yeop;Lee, Han-Seung
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.9 no.1
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    • pp.92-99
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    • 2021
  • CaO-based by-products composed of CaO, SO3, Al2O3, etc. are generally used as raw materials for CaO compounds. When applied to the recovered water of ready-mixed concrete, the hydration reaction of the powder material is accelerated and concrete performance can be improved. In this study, activated sludge was prepared to apply to the recovered water of ready-mixed concrete by mixing CaO-based hot-rolled slag(C12A7) in the recycling water of ready-m ixed concrete. Cem ent paste setting time and mortar compressive strength performance tests confirmed the effect on the hydration reaction. Therefore, the possibility of concrete application using activated sludge was confirmed.

Wastewater Treatment by Microorganism (미생물에 의한 발효처리)

  • ;Kunisuke Ichikawa
    • Microbiology and Biotechnology Letters
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    • v.8 no.2
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    • pp.135-142
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    • 1980
  • The process of biological treatment of organic wastewater is principally associated with those of self-purification in the natural water environment. The treatment system has e intensive function of stabilizing wastewater more effectively than in natural water, which is like natural water concentrated in a small space. Biological treatment of wastewater involves activated sludge and various modified process, trickling filter, rotating disk, oxidation ditch, etc. for aerobic decomposition and anaerobic processes such as anaerobic decomposition and methane fermentation. The basic characteristic of these processes is the use of mixed culture for the conversion of pollutants. This review forcuses on the various kinds of microorganisms related to each treatment processes. Kinetic analysis of the activated sludge process is discussed in order to understand the basis of control and maintenance of the biological treatment process.

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Treatment Characteristics of Wastewater with Flow Rate Variation in Anaerobic-Aerobic Activated Sludge Process

  • Lee Min-Gyu;Suh Kuen-Hack;Hano Tadashi
    • Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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    • v.1 no.1
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    • pp.11-17
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    • 1997
  • The treatment performances of anaerobic-aerobic activated sludge process were investigated under various operation conditions. The treatment system proposed in this study gave a relatively stable performance against hourly change of the flow rate and showed a satisfactory removal efficiency of nitrogen and phosphorus compounds under experimental conditions. The average removal efficiency of total nitrogen gradually decreased as the influent total nitrogen concentration was increased. High C/N ratio of the wastewater was required for the complete removal of nitrogen. Glucose as a carbon source was more efficient than starch and the removal ability for all components become higher with the increase of the fraction of glucose.

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Treatment Characteristics of Wastewater with Flow Rate Variation in Anaerobic-Aerobic Activated Sludge Process

  • Min-Gyu Lee;Kue
    • Journal of Environmental Science International
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    • v.1 no.1
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    • pp.11-17
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    • 1992
  • The treatment performances of anaerobic-aerobic activated sludge Process were investigated under various operation conditions. The treatment system proposed in this study gave a relatively stable performance against hourly change of the flow rate and showed a satisfactory removal efficiency of nitrogen and phosphorus compounds under experimental conditions. The average removal efficiency of total nitrogen gradually decreased as the influent total nitrogen concentration was increased. High C/N ratio of the wastewater was required for the complete removal of nitrogen. Glucose as a carbon source was more efficient than starch and the removal ability for all components become hither with the increase of the fraction of glucose.

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Effect on nitrogen removal in the intermittent aeration system with the anaerobic archaea added (혐기성 아키아 주입이 간헐폭기 시스템에서 질소제거에 미치는 영향)

  • Lee, Sang-Hyung;Park, Noh-Back;Park, Sang-Min;Jun, Hang-Bae
    • Journal of Korean Society of Environmental Engineers
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    • v.27 no.11
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    • pp.1186-1192
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    • 2005
  • The relationship between bacteria and anaerobic archaea, sludge yield coefficient and nitrogen removal rate were investigated in intermittent aeration systems(I/A) with added archaea, I/A and conventional activated sludge system. As the archaea solution was added to the I/A reactor, organic removal rate as well as nitrogen removal rate increased. Also, sludge production rate in I/A system added the archaea was maintained lower than other systems because sludge yield coefficient was decreased due to the role of anaerobic archaea such as anaerobic degradation of organics. The experimental data supported the possibility of symbiotic activated sludge system with anaerobic archaea under intermittent aeration, leading to the enhanced nitrogen removal. Crucial results to be presented are: 1) specific oxygen utilization rate(SOUR) of the I/A-arch system was $2.9\;mg-O_2/(g-VSS{\cdot}min)$. SOUR and nitrification rate of the sludge from the I/A-arch system was higher than those from the I/A and A/S reactors. 2) Removal efficiencies of $TCOD_{Cr}$ in the I/A-arch, I/A and A/S reactors were 93, 90 and 87%, respectively. 3) Nitrification occurred successfully in each reactor, while denitrification rate was much higher in the I/A-arch reactor. Efficiencies of TN removal in the I/A-arch, I/A and A/S reactors were 75, 63 and 33%, respectively.

A Pilot Study on Air Flotation Processes for Retrofitting of Conventional Wastewater Treatment Facilities (하수처리시설의 Retrofitting을 위한 파일럿 규모 공기부상공정 연구)

  • Park, Chanhyuk;Hong, Seok-Won;Lee, Sanghyup;Choi, Yong-Su
    • Journal of Korean Society of Water and Wastewater
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    • v.22 no.3
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    • pp.329-336
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    • 2008
  • The pilot study was conducted to evaluate the applicability of air flotation(AF) processes combined with biological nutrient removal(BNR) for the retrofitting of conventional wastewater treatment facilities. The BNR system was operated in pre-denitrification and intermittent aeration; developed ceramic membrane diffusers were installed to separate the solid-liquid of activated sludge at the bottom of a flotation tank. Before performing a pilot scale study, the size distribution of microbubbles generated by silica or alumina-based ceramic membrane diffusers was tested to identify the ability of solid-liquid separation. According to the experimental results, the separation and thickening efficiency of the alumina-based ceramic membrane diffuser was higher than the silica-based ceramic membrane diffuser. In a $100m^3/d$ pilot plant, thickened and return sludge concentration was measured to be higher than 15,000mg SS/L, therefore, the MLSS in the bioreactor was maintained at over 3,000mg SS/L. The effluent quality of the AF-BNR process was 4.2mg/L, 3.7mg/L, 10.6mg/L and 1.6mg/L for $BOD_5$, SS, T-N and T-P, respectively. Lastly, it was revealed that the unit treatment cost by flotation process is lower than about $1won/m^3$ compared to a gravity sedimentation process.

The Study of High Strength Organic Wastewater Treatment by Movinig Media Complete Mixing Activated Sludge System (회전매체를 가진 완전혼합활성슬러지 공법을 이용한 고농도 유기성 폐수 처리에 관한 연구)

  • 김흥태
    • Journal of Environmental Science International
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    • v.5 no.1
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    • pp.25-33
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    • 1996
  • This study was conducted to Investigate the biological treatment capability of MMCMAS(Movinig Media Complete Mixing Activated Sludge) reactor for high strength organic wastewater (Average BOD=800mg/l). And this experimental results were compared previous study for low strength organic wastewater (Average HOD=150mg/l) by the same reactor. In this study, we abtained following conclusions ; (1) The laboratory MMCMAS reactor demonstrated that SBOD removal efficiencies of more than 90% can be achieved at organic Bonding rates of 30.9 gBOD/$m^2$/d for high strength organic wastewater and 39.4 gBOD/$m^2$/d for low strength organic wastewater, respectively. (2) The nitrification rates of MMCMAS reactor was found same results of similiar organic loading rates. (3) The ratio of attached biomass to total biomass on the moving media varied in the range of 40 to 63% and 32 to 94% for high and low strength organic wastewater, respectively. And it was varied at the various concentration of influents for the similiar organic loading rates. The sludge production rates was found approximately 0.37 gVSS/$gBOD_{rem}$. in MMCMAS reactor.

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Sludge Thickening Performance of the Filtration Bio-reactor Equipped with Shadow Mask Filter Module (Shadow mask 여과 모듈을 이용한 슬러지 농축 특성)

  • Jung, Yong-Jun;Kwon, Koo-Ho;Min, Kyung-Sok
    • Journal of Korean Society on Water Environment
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    • v.21 no.1
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    • pp.29-33
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    • 2005
  • In order to recycle the waste material and to develop the thickening unit of waste activated sludge from wastewater treatment facilities, the filtration bio-reactor equipped with a shadow mask filter module was employed for this work from which the operating properties and parameters were drawn. The sludge thickening and filtration unit is made of cylindrical acryl tank(12cm i.d. ${\times}$ 58cm height: working volume of 6L), where the flat-sheet type of shadow mask filter module(pore size: 220~250um, opening area: 34.8~39.6%) was installed and the effluent was withdrawn from the effluent port at the lowest point of the reactor, and the filtration was performed only by the hydraulic pressure. For evaluating the operating performance of this reactor, some parameters such as the solid-liquid separation of different biomass concentrations, the water quality of filtrate, the aeration cleaning time and the cleaning effect were investigated. Depending on the MLSS concentrations, the different time to withdraw 3L of filtrate was required in which the longer filtration time was necessary for the higher MLSS concentrations caused by the thicker formation of cake layer: 40 minutes for 5,000 mg/L, 70 minutes for 10,000 mg/L and 100 minutes for 15,000 mg/L, where the concentrations of SS were 8.9, 6.7 and 6.5 mg/L, respectively. Under the same operating conditions (the intensity of aeration cleaning: 80 L/min, MLSS: 10,000 mg/L), the proper aeration cleaning time was revealed 30 seconds, and the stable formation of cake layer was in the range of 10 to 15 minutes. Therefore, the shadow mask considered as a waste material can be of use as a filter material for the sludge thickening system.

Analysis of Dominant Microorganisms of Bulking Sludge at Low Dissolved Oxygen Concentration using 16S rRNA Sequences (16S rRNA 염기서열을 이용한 낮은 용존산소농도에서 발생한 벌킹슬러지의 우점종 분석)

  • Kim, Yun-Jung;Park, Eun-Hye;Kim, Gyu-Dong;Nam, Kyoungphile;Chung, Tai Hak
    • Journal of Korean Society on Water Environment
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    • v.20 no.5
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    • pp.506-511
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    • 2004
  • Maintaining dissolved oxygen (DO) at sufficiently low concentration in the aeration tank at a wastewater treatment plant (WWTP) is essential for reduction of the costs of operation and maintenance. On the other hand, the low DO level may result in adverse effect on the integrity of the activated sludge, A typical and disastrous outcome frequently experienced is the outgrowth of filamentous microorganisms, which is called as filamentous bulking, In addition to the traditional methods such as sludge settleability and microscopic observation of the culture, molecular techniques including polymerase chain reaction (PCR) amplification followed by 16S rRNA sequencing were applied to identify filamentous bacteria present in bulking sludge under a condition of low DO concentration, Two morphologically distinct groups, presumably consisting of Sphaerofilus nafans, and Eikelboom Type 1701 or Type 1851, were identified through microscopic observation. They were further confirmed by subsequent 16S rRNA sequencing. Dominant filamentous bacteria identified by the molecular techniques were consisted of three major groups. Sequences of partial 16S rRNA cloned showed that the filamentous bulking organisms were closely related to Eikelboom Type 021N and Eikelboom Type 1701, and Sphaerotilus natans, respectively. Molecular methods were found to possess a strong potential of direct examination of the microbial community of an activated sludge system.

Recovery of high quality external carbon sources using crystallization from pretreated excess activated sludge by alkali and ozone (알칼리-오존 동시 전처리된 잉여슬러지로부터 결정화를 이용한 고품질 외부탄 소원 회수)

  • Seo, In S.;Kim, Hong S.;Kim, Byung G.;Kim, Youn K.
    • Journal of Korean Society of Water and Wastewater
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    • v.22 no.6
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    • pp.641-646
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    • 2008
  • In this research, recovery of high quality organics from excess activated sludge and its potential as a external carbon sources for BNR process was studied. By simultaneous treatment of alkali and ozone, TSS concentration was reduced by 32%, and RBDCOD fraction was increased by 76.2%, and major constitute of produced organic were acetic acid and propionic acid. Also, nitrogen and phosphorus were greatly solubilized. However, because acid-hydrolyzable phosphorus(AHP) was major part of solubilized phosphorus, $NH_4{^+}-N$ and $PO_4{^3}-P$ concentration were insufficient for effective formation of crystal like as MAP(Magnesium Ammonium Phosphate) and hydroxyapatite. By placing BPR reactor before alkali-ozone treatment reactor, $PO_4{^3}-P$ concentration in pretreated sludge was increased by 1.8 times, and improved potential of phosphorus recovery by crystallization. In experiment of crystallization, hydroxyapatite formation was more easily applied than MAP. By hydroxyapatite formation, $SCOD/PO_4-P$ ratio was greatly increased from 32.7 at control to 141.9 at $Ca^{2+}/PO{_4}^{3-}-P$ mole ratio of 2.4. The results based on this study indicated that the proposed system configuration has potential to reduce the excess sludge production, to recover phosphorus in usable forms as well as utilize organics as a external carbon source in BNR process.