title: Removal of high concentrations of NH(3) by a combined photoreactor and biotrickling filter system.
abstract: Average emission levels as high as 800 ppm(v) NH(3) have often been found during the anaerobic fermentation process. At these levels, NH(3) is regarded as an environmental toxic compound. High concentrations of NH(3) gas are difficult to treat in a single treatment process, suggesting that, in terms of economic cost and treatment performance, a coupled system may be a feasible technological alternative. In the coupled TiO(2) photocatalytic-biological treatment system evaluated here, the optimal gas retention time for NH(3) removal--in terms of removal efficiency and capital cost--was 26 s. High gas temperatures, high NH(3) concentrations, and low oxygen contents were unfavorable conditions for NH(3) removal by the photoreactor. The coupled system successfully removed concentrated NH(3) gas (R % > 97 %) under disrupted and shutdown conditions. The photoreactor component of the system successfully fulfilled its role as a pretreatment process and enhanced the performance of the biotrickling filter at a high inlet NH(3) load (2,277 g-N m(-3) day(-1)). Potential ammonia-oxidizing bacteria, including Bacillus cereus, Pseudomonas aeruginosa, and Stenotrophomonas sp., were isolated under the high inlet NH(3) load condition. These microbial strains have a potential as biological agents in the removal of high concentrations of NH(3) in waste gas or wastewater.
authors.affiliation: Department of Industrial Engineering and Management, China University of Science and Technology, Taipei, Taiwan.
authors.forename: Li-Chun
authors.initials: LC
authors.lastname: Wu
authors.forename: Cheng-Lang
authors.initials: CL
authors.lastname: Kuo
authors.forename: Ying-Chien
authors.initials: YC
authors.lastname: Chung
mesh_terms: D000393:Air Pollutants / Q000378:metabolism* / Q000528:radiation effects*; D000397:Air Pollution / Q000517:prevention & control; D000641:Ammonia / Q000378:metabolism* / Q000528:radiation effects*; D001419:Bacteria / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D058491:Bacterial Load; D001673:Biodegradation, Environmental; D002384:Catalysis; D055668:Photochemical Processes; D014025:Titanium / Q000737:chemistry; D014466:Ultraviolet Rays
chemical_list: D000393:Air Pollutants; C009495:titanium dioxide; D000641:Ammonia; D014025:Titanium