Method and device for removing ammonia from exhaust air from a livestock stable

A method for removing ammonia from exhaust air from a livestock stable, comprising passing said exhaust air and an aqueous liquid in a co-current manner through a device having multiple zones, which method comprises:

• i) passing said air and said aqueous liquid through a first zone of said device in which ammonia contained in said air is dissolved in the aqueous liquid while maintaining the pH in said first zone between 3.5 and 6.5 to allow conversion of ammonia to ammonium in said aqueous liquid;
• ii) passing said air and aqueous liquid containing dissolved ammonium from said first zone to a second zone of said device, wherein the second zone contains microorganisms capable to convert ammonium into nitrite, while maintaining the pH in said second zone between 2 and 8 to allow said microorganisms to convert ammonium to nitrite in said aqueous liquid;
• iii) passing said air and aqueous liquid containing dissolved nitrite from said second zone to a third zone of said device, in which the third zone the pH is maintained below 2 to convert nitrite to nitrate in said aqueous liquid,
• iv) discharging said air and aqueous liquid containing dissolved nitrate from said third zone.