Because it is the cheapest method to remove ammonia. No chemicals, no wastes.

Thanks Dear Dr Kótai

i think there are more responses than. air stripping is not effective for lower concentrations on ammonia and it unable to remove the lower conc.s of 100-200 mg/L and i dont have any response for this fact.

Ammonia in aq. solutions is in equilibirum with its protonated forms (depending on pH). So, a given amount of ammonia will be divided between NH3 and ammonium ion, the higher concentration of sum of ammonia species the higher amount of ammonia dissolved in water in ammonia form is present. If you saturate the solution with air, because of equlibriums between the gas/liquid phases, the gas phase will contain some amount of air (this amount will be released form aq. soln)., and the air stream will it transport from the equilibrium. It means, the free and summarized ammonia concentration in the solution will be decreased until the limit, where the partial pressure of NH3 above the solution becoames as low that this method becomes ineffective.

It strongly depedns on pH and temperature. The higher temp. and higher pH, the method is more effective - but not without limtits.

In my opinion it should be ammonia stripping where the air is mixed with the ammonia containing waste that lead to the formation of oxides of nitorgen. the dissipation of oxides of nitrogen depends on several factors.

Nitrogen oxides are formed only in the presence of metallic catalyst (NH3 ignition), but in aq. soln. the oxidation could be done (generally) until N2 but not under simple stripping conditions.

The aeration process does not rely on ammonia oxidation - it h=is based on the vaporization of the unionized species and so is pH dependent. As comments above indicate it is the generally the cheapest method available.

thank you all for excellent responses.

but, what factors are limited ammonia stripping in high pH and lower concentrations (below 100-200 mg/L).

THe concentration/pH/temp. -dependent equilibriums. When no dissolved molecular ammonia which can be in equilibrium with NH3 gas (with a given partial pressure of NH+) above the solution (Henry Dalton laws), no chance to strip out anything. Ammonia can form ammonium ion in aq. solns., so if the residual ammonia content is in ammonium ion form, the stripping is not effective.

thank you Dr Kotai

Thank you Dr. Kótai for your correction. I would also like to known how the metallic catalysts are added during ammonia stripping? In fact in natural wetlands H. Brix reported the oxidation of ammonia but he did not mention about the role of metallic catalysts. Although I agree with you. Does dissolved oxygen have any direct oxidizing potential in wastewater without any catalysts? Kindly suggest......

Air Ammonia stripping is suitable for wastewater with ammonia concentrations between 10 to 100mg/l. For higher concentrations steam stripping is preferable in combination with ammonia recovery to reduce operating costs.

Dear Jatin,

In natural wetland the "catalysts" are bacteria or other microorganisms. These are generally nitrificate ammonia then denitrifying bacteria convert it into N2.

Normally, oxygen cannot oxidize ammonia in water. But in the presence of bacteria or a catylst, selecting appropriate conditions, it is possible. In cas eof water, the oxation of ammonium ion is a better approximation, because iun dilute solution the main part is in ammonium ion form.

Getting confused, air stripping process work in low concentration (10-100 mg/l) or high concentration condition?

@Prasenjit Sadhukhan low concentration

I just want to know if the stripping process doesn't affect the anaerobic digestion process in the reactor? Because air stripped in the reactor is sometimes contaminated with oxygen while the condition is anaerobic.