Changes of pH in A2O Process System and its Impact on Nitrogen and Phosphorus Removal

2012 ◽  
Vol 588-589 ◽  
pp. 55-58
Author(s):  
Yong Feng Li ◽  
Jian Yu Yang ◽  
Guo Cai Zhang
Keyword(s):  
Phosphorus Removal ◽  
Ph Value ◽  
Removal Rate ◽  
Phosphorus Release ◽  
Ammonia Nitrogen ◽  
Biological Nutrient Removal ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Process System ◽  
High Level

Simulate sewage were used in an anaerobic-anoxic-aerobic biological nutrient removal system(A2O process), by observing the pHs in different compartments and its reflected changes in nitrogen and phosphorus removal, studied on the effects of different pHs on the removal of pollutants. The experiments indicates that the anaerobic phosphorus release showed the main performance of the decline of pH, denitrification in anoxic zone caused the rise of pH, uptake of phosphate in the aerobic zone mainly caused the continuous rise of pH. There is no evidently changes in COD removal, ammonia nitrogen get the highest removal as the pH value was between 8.0-8.5, when pH was at 6.5-7.5, the TN have the maximum removal rate, TP can keep in a high level when the pH was above 6.0.

Improvment of nitrogen and phosphorus removal in the anaerobic-oxic-anoxic-OXIC (AOAO) process by stepwise feeding

2000 ◽  
Vol 42 (3-4) ◽  
pp. 89-94 ◽  
Author(s):  
H.Y. Chang ◽  
C.F. Ouyang
Keyword(s):  
Carbon Source ◽  
Phosphorus Removal ◽  
Removal Rate ◽  
Feeding Strategy ◽  
Synthetic Wastewater ◽  
Biological Nutrient Removal ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Kjeldahl Nitrogen ◽  
P Removal

This investigation incorporated a stepwise feeding strategy into the biological process containing anaerobic/oxide/anoxic/oxide (AOAO) stages to enhance nitrogen and phosphorus removal efficiencies. Synthetic wastewater was fed into the experimental reactors during the anaerobic and anoxic stages and the substrates/nutrients were successfully consumed without recycling either nitrified effluent or external carbon source. An intrinsic sufficient carbon source developed during the anoxic stage and caused the NOx (NO2-N+NO3-N) concentration to be reduced from 11.85mg/l to 5.65mg/l. The total Kjeldahl nitrogen (TKN) removal rate was between 81.81%∼93.96% and the PO4-P removal ratio ranged from 93%∼100%. The substrate fed into the anaerobic with a Q1 flow rate and a Q2 into the anoxic reactor. The three difference experiments contained within this study produced Q1/Q2 that varied from 7/3, 8/2, and 9/1. The AOAO process saved nearly one-third of the energy compared with typical biological nutrient removal (BNR) system A2O processes.

A novel wastewater treatment process: simultaneous nitrification, denitrification and phosphorus removal

2004 ◽  
Vol 50 (10) ◽  
pp. 163-170 ◽  
Author(s):  
R.J. Zeng ◽  
R. Lemaire ◽  
Z. Yuan ◽  
J. Keller
Keyword(s):  
Phosphorus Removal ◽  
Batch Reactor ◽  
Phosphorus Release ◽  
Gas Analysis ◽  
Simultaneous Nitrification And Denitrification ◽  
Biological Phosphorus Removal ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Wastewater Treatment Process ◽  
Nitrification And Denitrification

Simultaneous nitrification and denitrification (SND) via the nitrite pathway and anaerobic–anoxic enhanced biological phosphorus removal (EBPR) are two processes that can significantly reduce the COD demand for nitrogen and phosphorus removal. The combination of these two processes has the potential of achieving simultaneous nitrogen and phosphorus removal with a minimal requirement for COD. A lab-scale sequencing batch reactor (SBR) was operated in alternating anaerobic–aerobic mode with a low dissolved oxygen concentration (DO, 0.5 mg/L) during the aerobic period, and was demonstrated to accomplish nitrification, denitrification and phosphorus removal. Under anaerobic conditions, COD was taken up and converted to polyhydroxyalkanoates (PHA), accompanied with phosphorus release. In the subsequent aerobic stage, PHA was oxidized and phosphorus was taken up to less than 0.5 mg/L at the end of the cycle. Ammonia was also oxidised during the aerobic period, but without accumulation of nitrite or nitrate in the system, indicating the occurrence of simultaneous nitrification and denitrification. However, off-gas analysis found that the final denitrification product was mainly nitrous oxide (N2O) not N2. Further experimental results demonstrated that nitrogen removal was via nitrite, not nitrate. These experiments also showed that denitrifying glycogen-accumulating organisms rather than denitrifying polyphosphate-accumulating organisms were responsible for the denitrification activity.

The Influence Factors in Denitrifying Phosphorus Removal

2013 ◽  
Vol 401-403 ◽  
pp. 2084-2087
Author(s):  
Ming Fen Niu ◽  
Si Li ◽  
Hong Jing Jiao ◽  
Jian Wei ◽  
Yuan Yang Sun ◽  
...  
Keyword(s):  
Retention Time ◽  
Phosphorus Removal ◽  
Ph Value ◽  
Influence Factors ◽  
Volume Ratio ◽  
Wastewater Sludge ◽  
Practical Application ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Denitrifying Phosphorus Removal

Denitrifying phosphorus removal can be achieved with the same matrix simultaneous nitrogen and phosphorus removal，is a hot topic of abroad study biological wastewater treatment，This is discussed the Influence factors of anoxic tank NO3- load, dissolved oxygen and the volume ratio of aerobic tank and anoxic tank, pH value of wastewater, sludge retention time (SRT), hydraulic retention time (HRT), mixed liquor suspended solids (MLSS) and temperature on denitrifying phosphorus removal, for denitrifying phosphorus removal process simulation, experimental research and practical application provides a reference and basis.

Biological nitrogen and phosphorus removal in UCT-type MBR process

2009 ◽  
Vol 59 (11) ◽  
pp. 2093-2099 ◽  
Author(s):  
H. Lee ◽  
J. Han ◽  
Z. Yun
Keyword(s):  
Phosphorus Removal ◽  
P Uptake ◽  
Biological Nutrient Removal ◽  
Anoxic Zone ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Nitrate Inhibition ◽  
Biological Nitrogen ◽  
P Removal ◽  
Production Characteristics

A lab-scale UCT-type membrane bio-reactor (MBR) was operated for biological nitrogen (N) and phosphorus (P) removal simultaneously. In order to examine biological nutrient removal (BNR) characteristics of MBR, the lab unit was fed with a synthetic strong and weak wastewater. With strong wastewater, a simultaneous removal of N and P was achieved while application of weak wastewater resulted in a decrease of both N and P removal. Recycled nitrate due to the limited organic in weak wastewater operation probably caused a nitrate inhibition in anaerobic zone. In step feed modification with weak wastewater, both N and P removal capability recovered in the system, indicating that the allocation of COD for denitrification at anoxic zone was a key to increase the biological P removal. In addition, the analysis on the specific P uptake rate in anoxic zone demonstrated that denitrifying phosphorus accumulating organism (dPAO) played an important role to remove up to 40% of P along with N. The sludge production characteristics of UCT-type MBR were similar to ordinary activated sludge with BNR capability.

Comparison of nutrient removal efficiency between pre- and post-denitrification wastewater treatments

2006 ◽  
Vol 53 (9) ◽  
pp. 169-175 ◽  
Author(s):  
K. Hamada ◽  
T. Kuba ◽  
V. Torrico ◽  
M. Okazaki ◽  
T. Kusuda
Keyword(s):  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Biological Nutrient Removal ◽  
Biological Phosphorus Removal ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Nutrient Removal Efficiency ◽  
Polyphosphate Accumulating Organisms ◽  
Biological Phosphorus ◽  
Denitrification Process

A shortage of organic substances (COD) may cause problems for biological nutrient removal, that is, lower influent COD concentration leads to lower nutrient removal rates. Biological phosphorus removal and denitrification are reactions in which COD is indispensable. As for biological simultaneous nitrogen and phosphorus removal systems, a competition problem of COD utilisation between polyphosphate accumulating organisms (PAOs) and non-polyphosphate-accumulating denitrifiers is not avoided. From the viewpoint of effective utilisation of limited influent COD, denitrifying phosphorus-removing organisms (DN-PAOs) can be effective. In this study, DN-PAOs activities in modified UCT (pre-denitrification process) and DEPHANOX (post-denitrification ptocess) wastewater treatments were compared. In conclusion, the post-denitrification systems can use influent COD more effectively and have higher nutrient removal efficiencies than the conventional pre-denitrification systems.

BICT biological process for nitrogen and phosphorus removal

2004 ◽  
Vol 50 (6) ◽  
pp. 179-188
Author(s):  
Y. Huang ◽  
Y. Li ◽  
Y. Pan
Keyword(s):  
Phosphorus Removal ◽  
Municipal Wastewater ◽  
Biological Process ◽  
Synthetic Wastewater ◽  
Nitrifying Bacteria ◽  
Biological Nutrient Removal ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Attached Growth ◽  
Removal Process

An updated biological nitrogen and phosphorus removal process - BICT (Bi-Cyclic Two-Phase) biological process - is proposed and investigated. It is aimed to provide a process configuration and operation mode that has facility and good potential for optimizing operation conditions, especially for enhancing the stability and reliability of the biological nutrient removal process. The proposed system consists of an attached-growth reactor for growing autotrophic nitrifying bacteria, a set of suspended-growth sequencing batch reactors for growing heterotrophic organisms, an anaerobic biological selector and a clarifier. In this paper, the fundamental concept and operation principles of BICT process are described, and the overall performances, major operation parameters and the factors influencing COD, nitrogen and phosphorus removal in the process are also discussed based on the results of extensive laboratory experiments. According to the experimental results with municipal sewage and synthetic wastewater, the process has strong and stable capability for COD removal. Under well controlled conditions, the removal rate of TN can reach over 80% and TP over 90% respectively, and the effluent concentrations of TN and TP can be controlled below 15 mg/L and 1.0 mg/L respectively for municipal wastewater. The improved phosphorus removal has been reached at short SRT, and the recycling flow rate of supernatant between the main reactors and attached-growth reactor is one of the key factors controlling the effect of nitrogen removal.

Boston Harbor Clean-Up: Comparison of Conventional Oxygen Activated Sludge with and without Anaerobic Selectors

1992 ◽  
Vol 25 (4-5) ◽  
pp. 281-287 ◽  
Author(s):  
P. T. Bowen ◽  
V. S. Magar ◽  
R. Otoski ◽  
T. McMonagle
Keyword(s):  
Activated Sludge ◽  
Phosphorus Removal ◽  
Pilot Scale ◽  
Ammonia Nitrogen ◽  
Design Parameters ◽  
Boston Harbor ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Activated Sludge Processes ◽  
Treatment Design

To determine secondary treatment design parameters for the Massachusetts Water Resources Authority Deer Island Treatment Facility, a pilot study was conducted. Due to the constricted site, oxygen activated sludge processes were considered. A pilot-scale conventional oxygen activated sludge (COAS) and COAS preceded by an anaerobic selector process (ASP) were compared. Both processes achieved comparable levels of total and soluble BOD, total and soluble COD, total nitrogen, ammonia nitrogen, and phosphorus removal. Higher percent removals occurred during the spring and summer flow periods. Neither process appeared more stable than the other with respect to changing influent loading and hydraulic stress. Differences in the process were the sludge settleability and sludge yield. The ASP had a slightly higher sludge yield than COAS, but the solids settled faster.

Two stage intermittent aeration membrane bioreactor for simultaneous organic, nitrogen and phosphorus removal

2000 ◽  
Vol 41 (10-11) ◽  
pp. 217-225 ◽  
Author(s):  
G.T. Seo ◽  
T.S. Lee ◽  
B.H. Moon ◽  
J.H. Lim ◽  
K.S. Lee
Keyword(s):  
Phosphorus Removal ◽  
Membrane Bioreactor ◽  
Removal Rate ◽  
Domestic Wastewater ◽  
Intermittent Aeration ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Aeration Conditions ◽  
Two Phases ◽  
Filtration Experiment

A submerged membrane bioreactor (SMBR) was operated in 2-stage intermittent aeration for simultaneous removal of organic matter, nitrogen and phosphorus. The system consists of two reactors with a total volume of 0.27 m3 (1st reactor 0.09 m3 and 2nd 0.18 m3). Real domestic wastewater was used as influent to the system. Membrane used for this experiment was hollow fiber polyethylene membrane with pore size of 0.1μm and effective surface area, 4 m2. The membrane was submerged in the 2nd reactor for suction type filtration. Experiment was carried out in two phases varying the time cycles of aeration and non-aeration. SRT was maintained at 25 days and HRT, 16–19 hours. MLSS concentration in the reactors was in the range of 2,700–3,400 mg/l. The MLSS internal recycling ratio was maintained at 100% of influent flow rate. When time cycles of aeration and non-aeration were set at 30/90 min and 60/60 min in reactor 1 and 2, the removal of BOD and COD was 98.3% and 95.6%, respectively. A relatively low nitrogen and phosphorus removal was observed in this condition (73.6% as T–N and 46.6% as T–P). However, with 60/60 min intermittent aeration conditions for both reactors, the removal rate of nitrogen and phosphorus for two weeks steady state were enhanced to 91.6% as TN and 66% as TP, respectively. Further a high organic removal (98% BOD and 96.2% COD) was achieved too. In these conditions, the membrane of flux declined from 0.1 m/d to 0.08 m/d and suction filtration was at 10–12 kPa for a month long operation period.

Soft sensors for control of nitrogen and phosphorus removal from wastewaters by neural networks

2002 ◽  
Vol 45 (4-5) ◽  
pp. 101-107 ◽  
Author(s):  
L. Luccarini ◽  
E. Porrà ◽  
A. Spagni ◽  
P. Ratini ◽  
S. Grilli ◽  
...  
Keyword(s):  
Phosphorus Removal ◽  
Biological Nutrient Removal ◽  
Batch Reactors ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Removal Processes ◽  
Pollutants Removal ◽  
Biological Nitrogen

In this paper, we describe the results of research aimed to evaluate the possibility of using a neural network (NN) model for predicting biological nitrogen and phosphorus removal processes in activated sludge, utilising oxidation reduction potential (ORP) and pH as NN inputs. Based on N and P concentrations predictions obtained via the NN, a strategy for controlling sequencing batch reactors (SBRs) phases duration, optimising pollutants removal and saving energy, is proposed. The NN model allowed us to reproduce the concentration trends (change in slope, or process end), with satisfactory accuracy. The NN results were generally in good agreement with the experimental data. These results demonstrated that NN models can be used as “soft on-line sensors” for controlling biological processes in SBRs. By monitoring ORP and pH, it is possible to recognise the N and P concentrations during different SBRs phases and, consequently, to identify the end of the biological nutrient removal processes. This information can then be used to design control systems.

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