• Journal of Environmental Science International
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• v.19 no.4
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• pp.483-490
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• 2010

The purpose of this study is to investigate the effect of influent phosphorus concentration on the nitrogen and phosphorus removal in sequencing batch reactor(SBR) and sequencing batch biofilm reactors(SBBRs) in order to recover the enhanced biological phosphorus removal (EBPR) capacity at the sludge of the deterioration of EBPR capacity. In SBBRs, comparing to SBR, the organic removal was occurred actively at the 1 st non-aeration period because of the active phosphorus release at this period. However, the variation of TOC removal according to the decrease of influent phosphorus concentration was not clearly shown both in SBR and SBBRs. In case of SBR losing EBPR capacity, the EBPR capacity was not recovered by the decrease of the influent phosphorus concentration from 7.5 mg/L to 0.9 mg/L. The nitrogen removal increased by the decrease of influent phosphorus concentration both in SBR and SBBRs.

• Environmental Engineering Research
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• v.15 no.1
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• pp.3-7
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• 2010

To better understand the ecology of tetrade forming organisms (TFOs) floating in a large amount of dairy wastewater treatment plant (WWTP) effluent (sequencing batch reactor [SBR]) during the inefficient phosphorus (P) removal process of an enhanced biological P removal system, the TFOs from the effluent of a full scale WWTP were separated and attempts made to culture the TFOs in presence/absence of oxygen. The intact TFOs only grew aerobically in the form of unicellular short-rods. Furthermore, to identify the intact TFOs and unicellular short-rods the DNAs of both were extracted, analyzed using their denaturing gradient gel electrophoresis (DGGE)-profiles and then sequenced. The TFOs and unicellular short-rods exhibited the same banding pattern in their DGGE-profiles, and those sequencing data resulted in their identification as Acinetobacter sp. The intact TFOs appeared in clumps and packages of tetrade cells, and were identified as Acinetobacter sp., which are known as strict aerobes and efficient P-removers. The thick layer of extracellular polymeric substance surrounding Acinetobacter sp. may inhibit phosphate uptake, and the cell morphology of TFOs might subsequently be connected with their survival strategy under the anaerobic regime of the SBR system.

• Membrane and Water Treatment
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• v.3 no.2
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• pp.133-140
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• 2012

The overall performance of BNR-MBR, so-called Anoxic-Anaerobic-Aerobic Membrane Bioreactor ($A^3$-MBR), developed for nutrient removal was studied to determine the efficiencies and mechanisms under different solid retention time (SRT). The reactor was fed by synthetic high-rise building wastewater with a COD:N:P ratio of 100:10:2.5. The results showed that TKN, TN and phosphorus removal by the system was higher than 95%, 93% and 80%, respectively. Nitrogen removal in the system was related to the simultaneous nitrification-denitrification (SND) reaction which removed all nitrogen forms in aerobic condition. SND reaction in the system occurred because of the large floc size formation. Phosphorus removal in the system related to the high phosphorus content in bacterial cells and the little effects of nitrate nitrogen on phosphorus release in the anaerobic condition. Therefore, high quality of treated effluent could be achieved with the $A^3$-MBR system for various water reuse purposes.

• Journal of Environmental Health Sciences
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• v.34 no.1
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• pp.76-85
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• 2008

Biological nutrient removal (BNR) sludge was added to a sequencing batch reactor (SBR) in the addition ratios of 0%, 20%, 40%, 50% while observing the variation of nutrient removal characteristics and microorganism groups. When the BNR sludge was added in a ratio over 40%, the characteristics of EBPR (enhanced biological phosphorus removal) was shown at the 27 days. However, a distinct BNR was not shown when the addition ratio of BNR sludge was lower than 40%. The organic removal efficiency were shown as 90% in all SBRs irrespective of the addition ratio of BNR sludge. At the 27 days, the phosphorus removal efficiencies were shown as 40%, 55%, 77% and 69%, respectively, according to the addition ratio of BNR sludge. Overall, efficient nitrification and phosphorus removal was shown when the added BNR sludge ratio was over 40%.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.6
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• pp.437-443
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• 2020

Biological phosphorus removal is accomplished by exposing PAO(phosphorus accumulating organisms) to anaerobic-aerobic conversion conditions. In the anaerobic condition, PAO synthesize PHB(polyhydroxybutyrate) and simultaneously hydrolysis of poly-p resulting phosphorus(Pi) release. In aerobic condition, PAO uptake phosphorus(Pi) more than they have released. In this study, cyanobacteria Synechococcus sp., which is known to be able to synthesize PHB like PAO, was exposed to anaerobic-aerobic conversion. If Synechococcus sp. can remove excess phosphorus by the same mechanism as PAO, synergistic effects can occur through photosynthesis. Moreover, Synechococcus sp. is known to be capable of synthesizing PHB using inorganic carbon as well as organic carbon, so even if the available capacity of organic carbon decreases, it was expected to show stable phosphorus removal efficiency. In 6 hours of anaerobic condition, phosphorus release occurred in both inorganic and organic carbon conditions but SPRR(specific phosphorus release rate) of both conditions was 10 mg-P/g-MLSS/day, which was significantly lower than that of PAO. When converting to aerobic conditions, SPUR(specific phosphorus uptake rate) was about 9 mg-P/g-MLSS/day in both conditions, showing a higher uptake rate than the control condition showing SPUR of 6.4 mg-P/g-MLSS/day. But there was no difference in terms of the total amount of removal. According to this study, at least, it seems to be inappropriate to apply Synechococcus sp. to luxury uptake process for phosphorus removal.

• Journal of Korean Society on Water Environment
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• v.27 no.6
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• pp.754-759
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• 2011

A sequencing batch reactor (SBR) was operated under different pH conditions to better understand the influence of pH to granulation in enhanced biological phosphorus removal systems. Granules from the SBR were also investigated using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Considerable decreases in the amount of phosphorus released per substrate provided under anaerobic conditions and the content of biomass polyphosphate under aerobic conditions were observed when pH was changed from 7.5 to 7.0, followed by 6.5. Aerobic granulation was also observed at pH 7.0. A number of bacteria with the typical morphological traits of tetrad-forming organisms (TFOs) were observed at pH 7.0, including large members of cluster. Filamentous bacteria were also there in large numbers. The occurrence and growth of granules were further enhanced at pH 6.5. A SEM analysis showed that the aerobic granules had a compact microbial structure with shaperical shape and morphologically consisted of aggregates of small coccoid bacteria and filamentous bacteria encapsulated by extracellular polymeric substance. The main material ions identified by EDX moreover revealed that the structural materials for polyphosphate in the granules include phosphorus, potassium and calcium. Therefore, these results strongly suggested that PAOs are a dominant population in the microbial community of the aerobic granules.

• Journal of Korean Society on Water Environment
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• v.29 no.6
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• pp.782-789
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• 2013

Enhanced biological phosphorus removal (EBPR) behavior and microbial characteristics in the anaerobic-aerobic SBR (PAO SBR) and the anaerobic-anoxic SBR (DPAO SBR) were examined in this research. For 392 days of operation, both SBRs have exhibited a good EBPR (or denitrifying EBPR) performance. $P_{release}/P_{influent}$ ratio was highest in both reactors after the stabilization, while the efficiency of phosphorus removal was decreased since the sludge granulation has been visually observed within the reactor. The comparative analysis of Pyrosequencing-based microbial population between PAO and DPAO sludges showed indirectly that Dechloromonas spp. could utilize $O_2$ and $NO_3{^-}-N$ as an electron acceptor and Accumulibacter phosphatis use only $O_2$ in EBPR system. Also, we concluded that Thauera spp. as a denitrifier contribute significantly to the anoxic phosphorus removal in the DPAO system.

• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.692-697
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• 2004

Biological phosphorus removal is characterized by complex interactions between different intracellular components of energy as PHA. Therefore, fundamental understanding of the behavior of the intracellular components and their influence on the removal of phosphorus is essential before control strategies to stabilize the proper process. The purpose of this study is to investigate relationship between release of phosphorus and synthesis of intracellular storage polymer. Mass of stored intracellular storage polymer was 21.2 mg PHA/L, 28.8 mg PHA/g MLSS. And phosphorus release/intracellular storage polymer synthesis rate was 1.8545 mg stored polymer/mg Phosphate. In the aerobic phase, mass of PAOs synthesis is 49.37 mg PAOs/L. And PAOs fraction was 6.7-6.9%. Thus intracellular storage polymer synthesis by PAOs is calculated as 493mg PHA/g PAOs.

• Journal of Industrial Technology
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• v.16
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• pp.5-11
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• 1996

While the enhanced biological phosphorus removal(EBPR), in anaerobic/aerobic condition, was known to remove phosphorus by means of metabolism of poly-P microorganisms, the phosphorus removed could be released in the form of ortho-P in the aerobic fixed biofilm reactor. This study was initiated to investigate the cause of ortho-P release in the aerobic fixed biofilm reactor. The resutls indicated that the phosphorus release was caused by autooxidation. The synthesis and release of phosphrous were related to the ORP and the boundary value for the phase change was about 170mV. In the synthesis phase, the phosphorus removal rate per COD removed was $0.023mgP_{syn}/mgCOD_{rem}$. The phosprous contents of the microorganism were 4.3 ~ 6.0% on a dry weight basis.

• Journal of Microbiology and Biotechnology
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• v.13 no.3
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• pp.385-393
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• 2003

Microbial communities were analyzed in an anaerobic/aerobic sequencing batch reactor (SBR) fed with glucose as a sole carbon source. Scanning electron microscopy (SEM) showed that tetrad or cuboidal packet bacteria dominated the microbial sludge. Quinone, slot hybridization, and 165 rRNA gene sequencing analyses showed that the Proteobacteria beta subclass and the Actinobacteria group were the main microbial species in the SBR sludge. However, according to transmission electron microscopy (TEM), the packet bacteria did not contain polyphosphate granules or glycogen inclusions, but only separate coccus-shaped bacteria contained these, suggesting that coccus-shaped bacteria accumulated polyphosphate directly and the packet bacteria played other role in the enhanced biological phosphorus removal (EBPR). Based on previous reports, the Actinobacteria group and the Proteobacteria beta subclass were very likely responsible for acid formation and polyphosphate accumulation, respectively, and their cooperation achieved the EBPR in the SBR operation which was supplied with glucose.