• Environmental Engineering Research
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• v.10 no.5
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• pp.257-263
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• 2005

A batch and a continuous type experiments were conducted to test the conditions for simultaneous phosphorus release and uptake, and denitrification, taking place in one process. The bacteria able to denitrify as well as to remove phosphorus were evaluated for the application to biological nutrient removal(BNR) process. In the batch-type experiment, simultaneous reactions of phosphorus release and uptake, and also denitrification were observed under anoxic condition with high organic and nitrate loading. However the rate and the degree of P release were lower than that occurred under anaerobic condition. BNR processes composed of anaerobic-anoxic-oxic(AXO), anoxic-anaerobic-oxic(XAO) and anoxic-oxic(XO) were operated in continuous condition. The anoxic reactors in each process received nitrate loading. In the AXO process, P release in anaerobic reactor and the luxury uptake in oxic reactor proceeded actively regardless to nitrate loading. However in XAO and XO processes, P release and luxury uptake occurred only with the nitrate loading less than $0.07\;kg{NO_3}^--N$/kgMLSS-d. With higher nitrate load, P release increased and the luxury uptake decreased. Therefore, it appeared that the application of denitrifying phosphorus-removing bacteria (DPB) to BNR process must first resolve the problem with decrease of luxury uptake of phosphorus in oxic reactor.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.2
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• pp.181-189
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• 2008

Phosphate is the limiting factor leading to the eutrophication in nature and has been usually removed by the luxury uptake of PAOs(Phosphate accumulating organisms). The purpose of this study was the control of wastewater treatment removing phosphorus. The control of wastewater treatment process was performed by optimal and adaptive control. They were performed as followings. Firstly the inflow phosphate concentration was measured and the optimal aeration time was calculated by simplified ASM No. 2 for the phosphate to be 1.0 mg/L in effluent. It was optimal control. But when the phosphate concentration in effluent was not 1.0 mg/L, adaptive control was necessary to coincide the objective of control with real value. Then it was performed as the objective phosphate concentration in effluent was changed according to calculation of errors and it was adaptive control. The wastewater treatment process had been controlled by them for about one month. The range of phosphate concentration in effluent 0.2$\sim$3.2 mg/L and the average of it was 1.0 mg/L. The limitation of luxury uptake occurred two times while wastewater treatment process was running. After the analysis of laboratory tests, we knew the reasons were the shortage of ammonia nitrogen and the excessive aeration.

• 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 Environmental Science International
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• v.16 no.11
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• pp.1271-1277
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• 2007

This study was conducted to investigate the ratios of phosphorus release to COD uptake, phosphorus release to nitrate removal, and phosphorus uptake to phosphorus release by DNPAOs(denitrifying phosphate accumulating organisms). In case $I{\sim}IV$, influent 1 were fed with synthetic wastewater with influent 2 $NO_3^--N$ injection to anoxic zone and the case V were fed with municipal wastewater with side stream oxic zone instead of influent 2 $NO_3^--N$ injection. As a result, the ratio of phosphorus release to carbon uptake was increased in accordance with nitrate supply. The DNPAOs simultaneously took up phosphate and removed nitrate from the anoxic reactor. In case $I{\sim}IV$, with above 20 mg/L of sufficient $NO_3^--N$ supply, phosphate was taken up excessively by the DNPAOs in anoxic condition. The large amount of both uptake and release of phosphorus occurred above 20 mg/L of nitrate supply, achieving the ratio of phosphorus uptake to phosphorus release to be 1.05. In case V, phosphate luxury uptake was not occurred in system due to 6.98 mg/L of insufficient $NO_3^--N$ supply and the ratio of phosphorus uptake to phosphorus release was 0.98. Consequently, if nitrate as the electron acceptor was sufficient in anoxic zone, the ratio was found to be high.

• KSBB Journal
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• v.25 no.1
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• pp.62-66
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• 2010

This study was carried out to get phosphorus uptake rate in aerobic condition with nitrate and nitrite. Nitrate and nitrite inhibited phosphorus accumulating organisms' (PAOs') luxury uptake in aerobic condition. Nitrite awfully decreased the phosphorus uptake rate in aerobic condition. At the influent of 10 mg ${NO_3}^-$-NL, the phosphorus uptake was decreased to 52% comparing that at no influent of nitrate. And at the influent of 10 mg ${NO_2}^-$-NL, the phosphorus uptake was decreased to 28% comparing that at no influent of nitrite. At the influent of 20 mg ${NO_3}^-$-NL, nitrite and nitrate were co-existed and the phosphorus uptake rate was decreased to 16% comparing that at no influent of nitrite and nitrate. Also, the denitrification was occurred by denitrifying glycogen accumulating organisms (DGAOs)/denitrifying phosphorus accumulating organisms (OPAOs) in spite of aerobic condition, and the phosphorus uptake rate was increased by the decrease of influent nitrate concentration at the aerobic condition. The inflection point in the phosphorus uptake rate was shown at the nitrite concentration of 1.5~2 mg/L.

• 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.

• Journal of environmental and Sanitary engineering
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• v.12 no.3
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• pp.1-7
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• 1997

이 연구에서는 SBR 공법을 이용하여 질소, 인 동시제거기장에 대해 관찰하고 BOD-SS loading변화에 따른 오염물질 제거효율에 대해 검토하였다. BOD, TN 및 TP 제거율은 $20^{\circ}C$에서 95%, 74% and 81%로 나타났으며, Phosphorus luxury uptake는 호기성이 시작된후 1,2시간후에 각각 67% 및 84%를 흡수 하는 것으로 관찰 되었으며, 호기성 말기의 농도는 $0.9mg/{\ell}$ 이하를 유지하였다. 80% 및 85% 이상의 안정된 질소 제거효율을 유지하기 위해서는 BOD-SS loading 값을 0.15 및 0.08 kg-BOD/kg-SS.day 이하로 유지하여야 하는 것으로 나타났다. 또한 1회 방류수량의 변화에 따른 관찰에서, 반응조 유효용량의 30%, 40% 및 50%를 유출할 경우 TN은 각각 78%, 72% 및 58%를 TP는 각각 81%, 77% 및 66%의 제거효율을 보였다.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.6
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• pp.691-698
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• 2014

This study investigated the effect of a co-culture of Scenedesmus dimorphus and nitrifiers using artificial wastewater on the removal of ammonium, nitrate and phosphate in the advanced treatment. To test the synergistic effect of the co-culture, we compared the co-culture treatment with the cultures using S. dimorphus-only and nitrifiers-only treatment as controls. After 6 days of incubation, nitrate was removed only in the co-culture treatment and total amount of N removal was 1.3 times and 1.6 times higher in the co-culture treatment compared to those in the S. dimorphus- and nitrifiers-only treatments, respectively. In case of total amount of P, co-culture treatment removed 1.2 times and 12 times more P than the S. dimorphus -and nitrifiers-only conditions, respectively. This indicates that the co-culture improved removal rates for ammonium, nitrate, and phosphate. This further implies that there was no need for denitrification of nitrate and luxury uptake of P processes because nitrate and phosphate can be removed from the uptake by S. dimorphus. In addition, co-culture condition maintained high DO above 7 mg/L without artificial aeration, which is enough for nitrification, implying that co-culture has a potential to decrease or remove aeration cost in the wastewater treatment plants.

• Korean Journal of Ecology and Environment
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• v.41 no.4
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• pp.554-562
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• 2008

To evaluate the limitation for epiphytic and planktonic algal growth, acid extractable inorganic phosphorus (AP), implying the luxury uptake phosphorus, was measured in five reed zones of Lake Biwa. The AP in epiphytic substances was 0.7 to 1.4 mg P surface stem $m^{-2}$ in summer and 1.2 to 2.8 mg P $m^{-2}$ in winter. On the other hand, the amount in planktonic substances was 1.4 to 5.7 mg P m -3 and 0.8 to 5.4 mg P $m^{-3}$ in both seasons. Contribution of AP in the epiphytic and planktonic phosphorus was 23 to 31% and 8 to 27% in summer, and 17 to 22% and 9 to 17% in winter. It suggests that in summer both epiphytic and planktonic algae had been luxuriously taken up phosphate into cells. The weight ratios of C : N : P were averaged 79 : 20 : 1 for the epiphytic substances and 81 : 12 : 1 for the particulate substances. On the other hand, the ratios without the luxurious phosphorus were 93 : 24 : 1 and 103 : 15 : 1, showing much higher values than the Redfield ratio. High ratio in the epiphytic substances indicates that the phosphorus is the limiting parameter, rather than nitrogen, regulating the growth of epiphytic algal populations.

• Journal of Environmental Health Sciences
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• v.40 no.4
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• pp.322-329
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• 2014

Objectives: The purpose of this study was to investigate the effect of BIO-CLOD on advanced wastewater treatment for enhanced removal efficiency and meeting the stringent discharge water requirements of wastewater treatment plants. Methods: Two experimental apparatuses consisting of anaerobic, anoxic and aeration tanks were operated. One included a BIO-CLOD cultivation tank. Organic and nutrient parameters and removal efficiency were analyzed by pH, BOD, CODcr, SS, T-N and T-P. Results: The average removal efficiencies of BOD, COD and SS from the apparatus with BIO-CLOD tank installation were 95.5%, 88.6% and 92.9%, respectively, and these were higher than the results from the apparatus without BIO-CLOD. The average TP removal efficiency with BIO-CLOD tank marked 56.0%, higher than the 47.3% from the apparatus without one. BIO-CLOD showed a higher performance for TN removal at 49.6%, compared to the result without BIO-CLOD of 34.3% Conclusion: By reaction with BIO-CLOD, ammonia removal was effective in the aeration tank, as was phosphorus release in the anaerobic tank. Phosphorus luxury uptake and nitrification in aeration tank proceeded smoothly. The application of BIO-CLOD can improve the decrease of odor and settleability of activated sludge in a wastewater treatment plant, as well as increase the removal efficiency of organic and nutrient materials in water.