Grober Green

Due to its high solubility, ammonia cannot be passed through water like many other gases. Ammonia is dissolved in water.

Method and device for scrubbing ammonia from air exhausted from animal rearing facilities.
Ammonia in the air exhausted from animal containment facilities may be removed by scrubbing the air with a solution of a suitable salt of an acidic proton donor such as alum. Ammonia may be removed from the air within any enclosed animal building which includes at least one air inlet and at least one outlet, a ventilation system having an air mover effective to draw fresh air into the building through the inlet and exhaust contaminated air through the outlet, and an air scrubber in communication with the outlet. Prior to exhausting the air into the environment, the air is passed through the scrubber where it is contacted with a solution of the salt of an acidic proton donor effective for flocculating ammonia therein. The flocculated ammonia may then be removed from the solution, which may then be recycled to the scrubber.

A Biotrickling Filter for Removing Ammonia and Odour in Ventilation Air from a Unit with Growing-Finishing Pigs

Abstract  – (full- article)

The results demonstrated that the filter significantly reduced the ammonia concentration (ppm) in the outlet air (P<0.05). Even though, the ammonia concentration before the filter ranged between 8.1 and 9.0 ppm during the winter period and 4.1 and 5.9 ppm during the summer period, the ammonia concentration after the filter was in the range of 1.2 to 2.4 ppm during the entire study. The filter significantly reduced the odour concentration (OUE/m3) in the outlet air (P<0.05). However, there were large variations in the odour removal efficiency, which ranged from an average of 54 % during the winter period and 28 % during the summer period. A possible explanation for the reduced odour removal efficiency during the summer was the increased ventilation rate, which reduced the retention time of the outlet air in the filter. It was observed that some areas on the filter were clogged up with dust and biofilm and this may also have impaired the odour removal. In conclusion, the filter was able to reduce the ammonia and odour concentrations in the outlet air from a unit with growing-finishing pigs. However, it is required to improve the odour removal efficiency and to find methods to increase the retention time and prevent the clogging with dust and biofilm.

The ventilation system was based on the principle of negative pressure ventilation. Fresh air entered the unit through a diffuse inlet in the ceiling. The outlet air was sucked out from the slurry channels and into ventilation channels under the solid floor in each side of the unit. The ventilation channels were connected to the filter rooms. The ventilation fan was placed on the clean side of the filter and the outlet air was drawn through the filter. The filter was composed by two vertical cellulose pads, which were continuously humidified with water. As the outlet air passed through the cellulose pads dust, ammonia and odour compounds in the air stream were degraded and metabolized by the biofilm on the pads.