Comparison study of the effects of temperature and free ammonia concentration on nitrification and nitrite accumulation

2008 ◽  
Vol 43 (2) ◽  
pp. 154-160 ◽  
Author(s):  
Jung-Hoon Kim ◽  
Xuejun Guo ◽  
Hung-Suck Park
Keyword(s):  
Ammonia Concentration ◽  
Free Ammonia ◽  
Nitrite Accumulation ◽  
Comparison Study ◽  
Effects Of Temperature ◽  
Free Ammonia Concentration

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.

Effects of pH and urea concentration on urea removal from dialysate by enzymatic conversion and gas absorption using a capillary hemodialyzer

1980 ◽  
Vol 3 (1) ◽  
pp. 36-40
Author(s):  
E. Pişkin ◽  
T.M.S. Chang
Keyword(s):  
Gas Phase ◽  
Ammonia Concentration ◽  
Urea Concentration ◽  
Gas Absorption ◽  
Free Ammonia ◽  
Enzymatic Conversion ◽  
Ph Values ◽  
Effects Of Ph ◽  
Hydrolysis Of ◽  
Free Ammonia Concentration

This paper reports the effects of initial urea concentrations and pH values on the performance of a capillary hemodialyzer for the removal of free ammonia (NH3) formed by enzymatic hydrolysis of urea. Air was chosen as the gas phase. NaOH was used for alkalinization of dialysate. It was shown that one of the most important parameters was free ammonia concentration. The degrees of alkalinization and the initial urea concentration, were also important. Although even without the addition of NaOH, about 42% of the initial urea can be removed in one hour.

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.

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.

Assessment of chloramination control strategy based on free-ammonia concentration

2009 ◽  
Vol 58 (1) ◽  
pp. 29-39 ◽  
Author(s):  
Skadi Motzko ◽  
Rolando Fabris ◽  
Alexander Badalyan ◽  
Ralph Henderson ◽  
Christopher W. K. Chow ◽  
...  
Keyword(s):  
Control Strategy ◽  
Ammonia Concentration ◽  
Free Ammonia ◽  
Free Ammonia Concentration

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.

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