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.

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.

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.

Free Ammonia Inhibition of Nitrification in River Sediments Leading to Nitrite Accumulation

1997 ◽  
Vol 26 (4) ◽  
pp. 1049-1055 ◽  
Author(s):  
R. V. Smith ◽  
L. C. Burns ◽  
R. M. Doyle ◽  
S. D. Lennox ◽  
B. H. L. Kelso ◽  
...  
Keyword(s):  
River Sediments ◽  
Free Ammonia ◽  
Nitrite Accumulation ◽  
Ammonia Inhibition ◽  
Inhibition Of Nitrification

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.

Anaerobic digestion of slaughterhouse waste with UF-membrane separation and recycling of permeate after free ammonia stripping

2005 ◽  
Vol 52 (1-2) ◽  
pp. 531-536 ◽  
Author(s):  
H. Siegrist ◽  
W. Hunziker ◽  
H. Hofer
Keyword(s):  
Anaerobic Digestion ◽  
Phosphorus Removal ◽  
Membrane Separation ◽  
Ammonia Concentration ◽  
Free Ammonia ◽  
Ammonium Concentration ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Digested Sludge ◽  
Ammonia Stripping

Anaerobic digestion can adapt to free ammonia to a certain extent. During the anaerobic digestion of slaughterhouse waste, however, an ammonia concentration of up to 15 g N l−1 can be reached in the sludge liquid and this will even inhibit adapted sludge. To lower this concentration, a fraction of the digester liquid must therefore be continuously separated from the digested sludge and the free ammonia stripped before the liquid is recycled to the digester. A mesophilic laboratory digester was successfully operated with an ammonium concentration of 4–5 g l−1 and a pH of 8.0–8.4. After free ammonia stripping, the excess liquid was treated in a laboratory SBR for nitrogen and phosphorus removal before being added to the receiving water. The effluent had no toxic effect on daphnia and algae.

Study on Nitrite Accumulation in Biological Aerated Filter Treating Municipal Wastewater

2011 ◽  
Vol 90-93 ◽  
pp. 2960-2964
Author(s):  
Shou Bin Zhang ◽  
Li Ping Qiu ◽  
Hong Lan Li
Keyword(s):  
Wastewater Treatment ◽  
Filtration Rate ◽  
Municipal Wastewater ◽  
Ph Value ◽  
Accumulation Rate ◽  
Nitrite Accumulation ◽  
Biological Aerated Filter ◽  
Hydraulic Loading ◽  
Aerated Filter

The nitrite accumulation in Biological Aerated Filter (BAF) treating simulated municipal wastewater was investigated and the possibility of nitrous nitrification in low ammonia wastewater treatment was discussed. The results indicate that the lower concentration of DO was of advantage to the formation of the nitrite accumulation. When the concentration of DO was controlled to less than 0.5 mg/L, the nitrite accumulation rate can improved significantly to the maximum over 80%. By adjusting pH, nitrite accumulation can take place in BAF. When the influent pH value was 6.5 to 7, the highest nitrite accumulation rate was 57%. But long-term stable nitrite accumulation cannot be obtained only through changing influent pH value. The increasing of hydraulic loading can contribute to nitrite accumulation. When the hydraulic loading was enhanced to 10 m3/(m2•h) , the average nitrite accumulation rate can be increased by 52.5 times. When concentration of DO was 1.0 to 1.5, influent pH was 6.5 to 7 and the filtration rate was 5 m/h, the nitrite accumulation of BAF reactor was of good stability. During 60 days’ running, the nitrite accumulation rate can keep at 65% to 75% stably and obvious nitrous nitrification was found.

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