Prototype of horizontal bio-trickling air scrubber (HBAS) for ammonia removal in swine farm

Abstract

Modelling of Bio-Trickling Air Scrubber (HBAS) system is one of the methods to treat biological odor and gas emission in air treatment of manufacturing facility management. A cheaper way of efficient gas elimination is using sprinkling water in the direction of air flow in the media microbial adhesion. Samples of ammonia gas was continuously collected throughout swine production for 20 weeks. The experimental systems consisted of six different conditions by varying the amount of scrubbed water, the space between water spray and media, and the amount of media materials. Microorganism species in media, which affected to ammonia removal, were also classified. The results indicated that the highest efficiency of ammonia removal was 51.9% at the experimental condition as follows: 1) water spray rate of turn on: turn off - 60 : 30 seconds, 2) distance between water spray and media of 1 meter, and 3) a half of media microbial adhesion area. The treated ammonia concentration was lower than the standard value of the chemical in working atmosphere as determined by the American Conference of Governmental Industrial Hygienist (ACGIH TLV), giving ammonia not more than 25 ppm. Additionally, media bio-scrubber could classify five bacteria species (Brachybacterium sp., Micromonospora sp., Methylobacterium sp., Rhodococcus rubber and Cellulosimicrobium sp.), which ammonia was used as a natural resource. The main mechanism in gas removal was proposed by the liquid adsorption, whereas the microorganism adhering to the media did not affect in statistical signification. Improvement of removal efficiency could be achieved by an increase of gas retention time in the system and the space between water spray and media.