• Advances in environmental research
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• 제5권3호
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• pp.169-178
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• 2016

This study aimed at determining the treatability of high-strength wastewater (chemical oxygen demand, COD>4000 mg/L) using combined anaerobic-aerobic granular sludge in lagoon systems. The lagoon systems were simulated in laboratory-scale aerated and non-aerated batch processes inoculated with dried granular microorganisms at a dose of 0.4 g/L. In the anaerobic batch, a removal efficiency of 25% was not attained until the 12th day. It took 14 days of aerobic operation to achieve sCOD removal efficiency of 94% at COD:N:P of 100:4:1. The best removal efficiency of sCOD (96%) was achieved in the sequential anaerobic-aerobic batch of 12 days and 2 days, respectively at COD:N:P ratio of 200:4:1. Sequential anaerobic-aerobic treatment can achieve efficient and cost effective treatment for high-strength wastewater in lagoon systems.

• 대한환경공학회지
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• 제31권12호
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• pp.1135-1142
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• 2009

본 연구는 고분자 응집제를 이용하여 짧은 시간에 입상형태의 슬러지를 제조한 다음, 입상슬러지를 호기성 입상화 장치에 주입하여 입상화를 시도하였다. 각 반응조에서 호기성 입자의 형성에 따른 입자의 크기, 밀도, 입자내 미생물 체외분비 고분자물질 등의 물리.화학적인 특성을 조사하였다. 입상형태의 슬러지를 호기성 입상화 장치에 주입하여 COD 부하량 3, 6, 9 $kg{\cdot}COD/m^3{\cdot}d$로 35일간 운전한 결과 최종 형성된 호기성 입장의 평균 크기는 각각 3.6 mm, 4.3 mm, 3.4 mm 이었고 호기성 입자의 침강속도는 각각 1.5 cm/s, 1.6 cm/s, 1.2 cm/s 이었다. COD 부하량에 따른 미생물 군집체의 비성장속도는 0.12 $d^{-1}$, 0.135 $d^{-1}$, 0.133 $d^{-1}$이었으며 전반적으로 호기성 입상화 장치에서는 COD 부하량이 $6kg{\cdot}COD/m^3{\cdot}d$로 운전된 반응조에서 호기성 입자의 물리 화학적인 특성이 우수하였다.

• 한국환경과학회지
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• 제32권7호
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• pp.483-492
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• 2023

In this study, the treatment of livestock wastewater using an aerobic granular sludge based sequencing batch reactor was investigated. The reactor operation was carried out by general injection and split injection methods. The average removal efficiency of organic matter after the adaptation period was 71.5 and 87.4%, respectively. Some untreated organic matter was attributed to recalcitrant organic matter. The average removal efficiency of total nitrogen was 65.6 and 88.4%, respectively. These results indicate that the denitrification reaction by split injection was carried out smoothly. As for the solids, the ratio of aerobic granular sludge/mixed liquor suspended solid can be determined as the main factor of the process operation, and the ratio increased gradually and finally reached 86.0%. Correspondingly, the sludge volume index (SVI) was also improved, reaching 54 mL/g at the end of operation, and it is believed that the application of a short settling time contributed to the improvement of settleability.

• Biotechnology and Bioprocess Engineering:BBE
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• 제8권1호
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• pp.54-57
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• 2003

H$_2$-producing bacteria were isolated from anaerobic granular sludge. Out of 72 colonies (36 grown under aerobic conditions and 36 under anaerobic conditions) arbitrarily chosen from the agar plate cultures of a Suspended sludge, 34 colonies (15 under aerobic conditions and 19 under anaerobic conditions) produced H2 under anaerobic conditions. Based on various biochemical tests and microscopic observations, they were classified into 13 groups and tentatively identified as follows: From aerobic isolates, Aeromonar spp. (7 strains), Pseudomonas spp. (3 strains), and Vibrio spp. (5 strains); from anaerobic isolates, Actinomyces spp. (11 Strains), Clostridium 5pp. (7 strains). and Porphyromonas sp. When glucose was used as the carbon substrate, all isolates showed a similar cell density and a H$_2$ production yield in the batch cultivations after 12 h (2.24-2.74 OD at 600 nm and 1.02-1.22 mol H$_2$/mol glucose, respectively). The major fermentation by-products were ethanol and acetate for the aerobic isolates, and ethanol, acetate and propionate for the anaerobic isolates. This study demonstrated that several H$_2$ producers in an anaerobic granular sludge exist En large proportions and their performance in terms of H$_2$ production is quite similar.

• 한국환경과학회지
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• 제30권12호
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• pp.1081-1092
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• 2021

In this study, the effect on the stability of Aerobic Granular Sludge (AGS) caused by an AGS separator was investigated. The AGS separator was a hydrocyclone. The main factors of the AGS separator were filter pore size (0.125~0.600 mm), conical-to-cylindrical ratio (1.5~3.0), and operating time (1~20 min). The AGS/mixed liquor suspended solid (MLSS) ratio gradually increased to 0.500 mm (AGS/MLSS: 84.3±3.0%). AGS was best separated at the conical-to-cylindrical ratio of 2.5 (AGS/MLSS: 84.7±3.3%). As the operating time increased, the AGS separation performance also tended to increase. The shortest AGS separator run time, but the highest AGS separation performance was 10 min (87.0±2.5%). AGS stability was evaluated by operating the selected AGS separator and sequencing batch reactor. The average removal efficiencies of TOC, TCOD_Cr, SS, TN, and TP were 95.7%, 96.9%, 93.0%, 89.0%, and 96.2%, respectively, which met the effluent standards in Korea. In addition, the AGS/MLSS ratio tended to remain constant, and the sludge volume index demonstrated a tendency to decrease from 140 mL/g to 70 mL/g. During the operation, the particles of AGS in optical microscope observations gradually increased.

• 한국환경과학회지
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• 제28권7호
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• pp.607-615
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• 2019

The purpose of this study is to biological treatment of high salinity wastewater using Aerobic Granular Sludge (AGS). In laboratory scale's experiments research was performed using a sequencing batch reactor, and evaluation of the denitrification reaction in accordance with the injection condition of salinity concentration, surface properties of microorganisms, and sludge precipitability was performed. The results showed that the salinity concentration increased up to 1.5%, and there was no significant difference in the nitrogen removal efficiency; however, it showed a tendency to decrease gradually from 2.0% onward. The specific denitrification rate (SDNR) was 0.052 - 0.134 mg $NO_3{^-}-N/mg$ MLVSS (mixed liquor volatile suspended solid)${\cdot}day$. The MLVSS/MLSS (mixed liquor suspended solid) ratio decreased to 76.2%, and sludge volume index ($SVI_{30}$) was finally lowered to 57 mL/g. Using an optical microscope, it was also observed that the initial size of the sludge was 0.2 mm, and finally it was formed to 0.8-1.0 mm. Therefore, salinity injection provides favorable conditions for the formation of an AGS, and it was possible to maintain stable granular sludge during long-term operation of the biological treatment system.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.417-420
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• 2008

Recently, the interest in NDMA(N-nitrosodimethylamine) has increased due to its recognition as a pollutant by Ontario Ministry of Environment and Energy and California Department of Health Sciences. It is, in fact, one of the DBPs(Disinfection By-products) which appears due to chlorination and is reported to be fatal if exposed continuously to human body. Due to uncertainty in mechanism to remove it, its treatment is not yet carried out. In this experiment, treatment of biological NDMA is carried out by letting it adsorbed on Granular Sludge and then filtering the medium through MF(Microfiltration) and UF(Ultrafiltration) membranes. Granular Sludge is adapted to aerobic and anaerobic conditions for 7 days and the experimental conditions are MLSS of 8000mg/L, COD of 250mg/L, TN of 12.5mg/L, and TP of 2.5mg/L. Several batch tests were carried out and samples were collected with the interval of 1 hour. Samples were measured by LSC(Liquid scintillation counter) after filtering by MF and UF. In batch test with granular sludge the permeate concentrations(removal efficiencies) of NDMA by MF and UF were 71.7ng/L(32.0%) and 62.0ng/L(43.7%) at aerobic state, and 52.0ng/L(49.2%) and 47.6ng/L(58.9%) at anaerobic state, respectively. Hence, UF membrane showed about 10% more removal efficiency than MF and removal efficiency at anaerobic condition was 15% more than that at aerobic condition.

• Journal of Microbiology and Biotechnology
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• 제27권10호
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• pp.1798-1807
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• 2017

The differentiations in nitrogen-converting activity and microbial community structure between granular size fractions in a continuous completely autotrophic nitrogen removal over nitrite (CANON) reactor, having a superior specific nitrogen removal rate of $0.24g/(g\;VSS{\cdot}h)$, were investigated by batch tests and high-throughput pyrosequencing analysis, respectively. Results revealed that a high dissolved oxygen concentration (>1.8 mg/l) could result in efficient nitrite accumulation with small granules (0.2-0.6 mm in diameter), because aerobic ammonium-oxidizing bacteria (genus Nitrosomonas) predominated therein. Meanwhile, intermediate size granules (1.4-2.0 mm in diameter) showed the highest nitrogen removal activity of $40.4mg/(g\;VSS{\cdot}h)$ under sufficient oxygen supply, corresponding to the relative abundance ratio of aerobic to anaerobic ammonium-oxidizing bacteria (genus Candidatus Kuenenia) of 5.7. Additionally, a dual substrate competition for oxygen and nitrite would be considered as the main mechanism for repression of nitrite-oxidizing bacteria, and the few Nitrospira spp. did not remarkably affect the overall performance of the reactor. Because all the granular size fractions could accomplish the CANON process independently under oxygen limiting conditions, maintaining a diversity of granular size would facilitate the stability of the suspended growth CANON system.

• 대한환경공학회지
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• 제31권12호
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• pp.1143-1150
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• 2009

본 연구는 고분자 응집제를 이용하여 단시간에 입상형태의 슬러지를 제조한 후 연속회분식 장치에 주입하여 호기성 입상화를 시도하였다. 연속회분식 반응조에서 호기성 입자의 형성에 따른 입자의 크기, 침강속도, 표면전하, 비산소 소비율 등의 물리 화학적인 특성을 조사하였다. 입상형태의 슬러지를 연속회분식 장치에 주입하여 COD 부하량 $5.4kg{\cdot}COD/m^3{\cdot}d$로 운전한 결과 운전경과 20일만에 2.6 mm 내외의 호기성 입자를 형성하였으며, 최종형성된 호기성 입자의 침강속도, 비산소 소비율, 표면전하, 다당류/단백질비는 각각 1.7 cm/s, $346mg{\cdot}O_2/g{\cdot}MLVSS{\cdot}hr,\;(-)0.26{\cdot}meq/g{\cdot}MLVSS$, 2.06 mg/mg을 나타내었다.

• 한국환경과학회지
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• 제28권8호
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• pp.669-676
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• 2019

The purpose of this study was to evaluate the effects of different Hydraulic Retention Times (HRTs) on the contaminant removal efficiency using Aerobic Granular Sludge (AGS). A laboratory-scale experiment was performed using a sequencing batch reactor, and the Chemical Oxygen Demand (COD), nitrogen, orthophosphate removal efficiency, AGS/MLSS ratio, and precipitability in accordance with the HRT were evaluated. As a result, the COD removal efficiency was not significantly different with the reduction in HRT, and at a HRT of 6 h, the removal rate was slightly increased owing to the increase in organic loading rate. The nitrogen removal efficiency was improved by injection of influent division at a HRT of 6 h. As the HRT decreased, the MLSS and AGS tended to increase, and the sludge volume index finally decreased to 50 mL/g. In addition, the size of the AGS gradually increased to about 1.0 mm. Therefore, the control of HRT provides favorable conditions for the stable formation of AGS, and is expected to improve the contaminant removal efficiency with the selection of a proper operation strategy.