Modelling of biological nitrogen removal during treatment of piggery wastewater

2007 ◽  
Vol 55 (10) ◽  
pp. 11-19 ◽  
Author(s):  
F. Béline ◽  
H. Boursier ◽  
F. Guiziou ◽  
E. Paul
Keyword(s):  
Experimental Data ◽  
Maximum Growth ◽  
Ammonia Concentration ◽  
Pilot Scale ◽  
Free Ammonia ◽  
Effect Of Temperature ◽  
Nitrification Rate ◽  
Nitrite Accumulation ◽  
Piggery Wastewater ◽  
Pilot Scale Reactor

During this study, a mathematical model simulating piggery wastewater treatment was developed, with the objective of process optimisation. To achieve this, the effect of temperature and free ammonia concentration on the nitrification rate were experimentally studied using respirometry. The maximum growth rates obtained were higher for ammonium-oxidising biomass than for nitrite-oxidising biomass for the temperatures above 20 °C; values at 35 °C were equal to 1.9 and 1.35 day−1, respectively. No inhibition of nitrification was observed for free ammonia concentrations up to 50 mgN/L. Using these data with others experimental data obtained from a pilot-scale reactor to treat piggery wastewater, a model based on a modified version of the ASM1 was developed and calibrated. In order to model the nitrite accumulation observed, the ASM1 model was extended with a two-step nitrification and denitrification including nitrite as intermediate. Finally, the produced model called PiWaT1 demonstrated a good fit with the experimental data. In addition to the temperature, oxygen concentration was identified as an important factor influencing the nitrite accumulation during nitrification. Even if some improvements of the model are still necessary, this model can already be used for process improvement.

Nitrite accumulation in submerged biofilters - combined effects

1996 ◽  
Vol 34 (3-4) ◽  
pp. 371-378 ◽  
Author(s):  
F. Fdz-Polanco ◽  
S. Villaverde ◽  
P. A. Garcia
Keyword(s):  
Ammonia Concentration ◽  
Relative Activity ◽  
Free Ammonia ◽  
Effect Of Temperature ◽  
Ammonia Oxidizer ◽  
Ammonium Concentration ◽  
Nitrite Accumulation ◽  
Biological Aerated Filter ◽  
Ammonia Inhibition ◽  
Aerated Filter

The combined effect of temperature, pH and ammonium concentration over the nitrite accumulation phenomena in situations of free ammonia inhibition, their effect over the ammonia and nitrite oxidizer microorganiisms influence over the nitrification, have been studied in an Up-flow Biological Aerated Filter (UBAF). The free ammonia inhibition effect highly depends on the values of pH, temperature and ammonium concentration. For the same specific free ammonia concentration different values of temperature, pH and ammonium concentration bring about different nitrite accumulations. In conditions of no free ammonia inhibition and low values of temperature and pH, high ammonium concentrations bring about a higher relative activity of ammonia oxidizer microorganisms of the filter increases the nitratation efficiency in zones close to the outlet and will favour the nitrite accumulation in situations of free ammonia inhibition.

Preliminary assessment of a shortcut in nitrogen removal from wastewater

1986 ◽  
Vol 13 (6) ◽  
pp. 600-605 ◽  
Author(s):  
O. Turk ◽  
D. S. Mavinic
Keyword(s):  
Nitrogen Removal ◽  
Oxygen Demand ◽  
Ammonia Concentration ◽  
Free Ammonia ◽  
Nitrite Reduction ◽  
Nitrification Rate ◽  
Nitrite Accumulation ◽  
Nitrite Level ◽  
In Series ◽  
System 2

The objective of this long-term research project was to demonstrate the feasibility of removing nitrogen from highly nitrogenous wastewater by (a) blocking the nitrification process at the intermediary nitrite level through the action of free ammonia and (b) subsequently reducing the nitrite to nitrogen gas. The success of such a process could lead to substantial reductions in nitrogen removal costs.Two identical bench-scale activated sludge systems were operated for 147 days, in the initial phase. Each system was composed of four equal-sized, completely mixed cells in series. The free ammonia concentration was highest in the first cell of each system. It averaged 2 mg NH3-N/L in the first system and 5 mg NH3-N/L in the second. Nitrite buildup, in excess of 80% of the oxidized nitrogen present, was induced and sustained for around 2 months in all cells of the second system, after which time a steady decline occurred. Nitrite buildup could not be sustained in the first system. Average chemical oxygen demand (COD) for nitrite reduction was 40% lower than that for nitrate reduction. The nitrification rate for the ammonia oxidizers was similar for both systems. The presence of up to 100 mg [Formula: see text] nitrite in system 2 caused no discernible inhibition. Subsequent runs proved that nitrite accumulation could not be sustained indefinitely, owing to acclimation to free ammonia levels as high as 22 mg NH3-N/L. Periodic resting and flushing may be required; further research is being pursued along these lines. Key words: biological treatment, denitrification, nitrification, nitrite, nitrogen removal, nitrogenous wastewater.

scholarly journals Influence of dissolved oxygen on nitrification kinetics in a circulating bed reactor

1998 ◽  
Vol 37 (4-5) ◽  
pp. 189-193 ◽  
Author(s):  
V. Lazarova ◽  
R. Nogueira ◽  
J. Manem ◽  
L. Melo
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Municipal Wastewater ◽  
Ammonia Concentration ◽  
Pilot Scale ◽  
Biofilm Reactor ◽  
Laboratory Scale ◽  
Nitrification Rate ◽  
Nitrification Kinetics ◽  
Laboratory Scale Reactor

The influence of dissolved oxygen concentration in nitrification kinetics was studied in a new biofilm reactor, the circulating bed reactor (CBR). The study was carried out partly at laboratory scale with synthetic water containing inorganic carbon and nitrogen compounds, and partly at pilot scale for secondary and tertiary nitrification of municipal wastewater. The experimental results showed that either the ammonia or the oxygen concentration could be limiting for the nitrification rate. The transition from ammonia to oxygen limiting conditions occurred for an oxygen to ammonia concentration ratio of about 1.5 - 2 gO2/gN-NH4+ for both laboratory- and pilot-scale reactors. The nitrification kinetics of the laboratory-scale reactor was close to a half order function of the oxygen concentration, when oxygen was the rate limiting substrate.

Modeling bioaugmentation with nitrifiers in membrane bioreactors

2014 ◽  
Vol 71 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Alberto Mannucci ◽  
Giulio Munz ◽  
Gualtiero Mori ◽  
Jacek Makinia ◽  
Claudio Lubello ◽  
...  
Keyword(s):  
Experimental Data ◽  
Linear Correlation ◽  
State Of The Art ◽  
Pilot Scale ◽  
Membrane Bioreactors ◽  
Operating Conditions ◽  
Effect Of Temperature ◽  
Preliminary Step ◽  
Temperature Time ◽  
Activated Sludge Models

Bioaugmentation with nitrifiers was studied using two pilot-scale membrane bioreactors, with the purpose of assessing the suitability of state-of-the-art activated sludge models (ASMs) in predicting the efficiency of bioaugmentation as a function of operating conditions. It was demonstrated that the temperature difference between seeding and seeded reactors (ΔT) affects bioaugmentation efficiency. Experimental data were accurately predicted when ΔT was within a range of up to 10 °C at the higher range, and when the temperature was significantly lower in the seeded reactor compared to the seeding one, standard ASMs overestimated the efficiency of bioaugmentation. A modified ASM, capable of accurately representing the behavior of seeded nitrifying biomass in the presence of high ΔT, would require the inclusion of the effect of temperature time gradients on nitrifiers. A simple linear correlation between ΔT and the Arrhenius coefficient was proposed as a preliminary step.

Temperature effect on nitrifying bacteria activity in biofilters: activation and free ammonia inhibition

1994 ◽  
Vol 30 (11) ◽  
pp. 121-130 ◽  
Author(s):  
F. Fdz-Polanco ◽  
S. Villaverde ◽  
P. A. García
Keyword(s):  
Plug Flow ◽  
Biomass Concentration ◽  
Ammonia Concentration ◽  
Free Ammonia ◽  
Nitrifying Bacteria ◽  
Ammonium Concentration ◽  
Nitrite Accumulation ◽  
Specific Rate ◽  
Activation Effect ◽  
Ammonia Inhibition

Nitrifying bacteria activity and concentrations depend on specific free ammonia concentration (ratio NH3/biomass), that is a function of temperature, pH, ammonium concentration and nitrifying biomass concentration. So, temperature is a key parameter in the nitrification process producing two opposite effects: bacteria activation and free ammonia inhibition. These phenomena are studied in an up-flow biological aerated filter (UBAF) settled by a nitrifying biofilm (measured as Volatile Attached Solids, VAS). The plug flow allows to disclosure of both effects, activation and inhibition. For Nitrosomonas bacteria only an activation effect was observed; their activity reaches a maximum at 28-29 °C. For Nitrobacter the free ammonia inhibition prevails against the activation effect for values greater than 1 mg N-NH3/mg VAS allowing nitrite accumulation of 80%; this inhibition threshold value for nitrifying biofilm is obtained measuring the specific rate of utilization of substratum per unit of biomass (μmax/Y) by activity test. The knowledge of this threshold in a biofilm process is fundamental in order to control the nitrite accumulation in nitrifying biofilm reactors.

Nitrite accumulation in the treatment of wastewaters with high ammonia concentration

2003 ◽  
Vol 48 (3) ◽  
pp. 135-141 ◽  
Author(s):  
W. Yang ◽  
J. Vollertsen ◽  
T. Hvitved-Jacobsen
Keyword(s):  
Nitrous Acid ◽  
Ammonia Oxidation ◽  
Ammonia Concentration ◽  
Pilot Scale ◽  
Nitrite Accumulation ◽  
Operational Parameters ◽  
Treatment Unit ◽  
Operational Conditions ◽  
Reject Water ◽  
Oxidation Rates

Different operational parameters of the nitritation process were investigated in both jar tests and pilot scale Sequencing Batch Reactors (SBRs). In the laboratory study, 100-1,200 mg N l-1 of ammonia was used. The pH and temperature were varied. Batch experiments were done on municipal sludge, pectin industrial sludge and sludge from a reject water treatment unit. Ammonia oxidation was observed with relative nitrite accumulations from 2% to 100% and ammonia oxidation rates from 0.01 to 0.58 g N g VSS-1 d-1. The nitritation process and relative nitrite accumulation were highly affected by pH, temperature and the sludge type. pH 8.0-8.5 and temperature 30°C were found favourable for the nitritation. Pilot SBR systems for treating reject water achieved 100% of nitrite accumulation under the operational conditions of pH 7.5-8.0, temperature 30°C and dissolved oxygen (DO) 1.0 mg l-1. Six months of operation revealed that pH regulations were essential to avoid the inhibitions by either free ammonia or nitrous acid. At an unionized ammonia concentration of approximately 20 mg NH3-N l-1, half of the normal nitritation ability still remained. Total inhibition occurred when the concentration of nitrous acid reached 3.0 mg HNO2-N l-1. However, both types of inhibitions were reversible in the SBR with a proper operation control. Stable and controllable nitritation could be achieved in pilot scale.

Effect of inorganic carbon on nitrite accumulation in an aerobic granule reactor

2006 ◽  
Vol 53 (12) ◽  
pp. 285-294 ◽  
Author(s):  
T. Tokutomi ◽  
T. Kiyokawa ◽  
C. Shibayama ◽  
H. Harada ◽  
A. Ohashi
Keyword(s):  
Inorganic Carbon ◽  
Average Diameter ◽  
Pilot Scale ◽  
Oxygen Limitation ◽  
Nitrite Accumulation ◽  
High Concentration ◽  
Nitrification Process ◽  
Do Concentration ◽  
Pilot Scale Reactor ◽  
Scale Reactor

Pilot scale experiments were performed to evaluate the potential of nitrite type nitrification process with an airlift reactor and granular biomass. Initially, oxygen limitation was used as the main control parameter for accumulating nitrite in the effluent. After 30 d operation, the maximum nitrite conversion rate reached 2.5 kgNO2-N m−3 d−1, average diameter of the granule was 0.7 mm. Nitrite type reaction continued over 100 d, but nitrate formation increased after 150 d of operation. Once nitrate formation increased, oxygen limitation could not eliminate nitrite oxidising bacteria from granule. To overcome nitrate formation, laboratory scale batch experiments were conducted and it revealed a high concentration of inorganic carbon which had a significant effect on nitrite accumulation. Following this new concept, inorganic carbon was fed to the pilot scale reactor by changing pH adjustment reagent from NaOH to Na2CO3 and nitrite accumulation was recovered successfully without changing DO concentration. These results show that a high concentration of inorganic carbon is one of the control parameters for accumulating nitrite in biofilm nitrification system.

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