Mohammad Javad Jafari - Department of Occupational Health, School of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Leila Omidi - Department of Occupational Health, School of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Mansour Rezazadeh Azari - Department of Occupational Health, School of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Mohammad Reza Massoudi - Department of Environmental Health, School of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran

The selection of the packing media is concerned when ammonia is going to be scrubbed through apacked tower. In this study, a packed tower with two types of packing including raschig rings and PVC were used to remove the ammonia gas from air stream. Three gas flow rates as well as three ammonia concentrationsand three pH of scrubbing liquid were applied. The level of ammonia at the inlet and out let of the packed towerwas measured through a direct reading device. The removal efficiency of column significantlyincreased in both modes, packed with raschig rings and PVC (p<0.001) as the inlet concentrationof ammonia gas wasincreased. With decreasing pH of scrubbing liquid from 7 to 5, the removalefficiency of the tower packedwith raschig rings significantly increased (p< 0.01). The head loss acrossthe bed was significantly increased(p< 0.001) as air flow rate increased from 5 to 10 and 10 to 15 l/s. The head loss across the bed was also higherwhen column was packed with raschig rings rather than packed with PVC. The lower ammonia removalefficiency of PVC rings could be ignoredconsidering their other advantages such as light weight, low headlosses, low initial and operating costs.

Raschig rings, PVC, Packed tower, Ammonia removal, Efficiency, pH