The biofiltration process is a promising technology for the treatment of dilute styrene emissions in air (less than 1 g‚m -3 ). The efficiency of this process is however strongly dependent upon various operational parameters such as the filter bed characteristics, nutrient supplies, input contaminant concentrations, and gas flow rates (gas residence times). The biofiltration of air containing styrene vapors was therefore investigated, employing a novel biomass filter material, in two identical but separate laboratory scale biofiltration units (units 1 and 2), both biofilters being initially inoculated with a microbial consortium. Each biofilter was irrigated with a nutrient solution supplying nitrogen in one of two forms; i.e., mainly as ammonia for unit 1 and exclusively as nitrate for unit 2. The experimental results have revealed that greater styrene elimination rates (up to 141 g‚m -3 ‚h -1 ) are achieved in the biofilter supplied with ammonia as the major nitrogen source in comparison to the lesser elimination performance (up to 50 g‚m -3 ‚h -1 ) obtained with the nitrate provided biofilter. However, in achieving the high styrene removal rates in the ammonia supplied biofilter, the excess of biomass accumulates on the filtering pellets and causes progressive clogging of the filter media. Furthermore, the effectiveness of nitrate supply as the sole nitrogen nutrient form, on reducing or controlling the biomass accumulation in the filter media in comparison to ammonia, could not be satisfactorilly demonstrated because the two biofilters operated with very different styrene elimination capacities. The monitoring of the carbon dioxide concentration profile through both biofilters revealed that the ratio of carbon dioxide produced to the styrene removed was approximately 3/1, which confirms the complete biodegradation of removed styrene, given that some of the organic carbon consumed is also used for the microbial growth. The effects of the most important design parameters, namely styrene input concentrations and gas flow rates, were investigated for each nutrient solution.
A laboratory scale biofilter system was used to eliminate toluene and ethanol, the main solvents employed in lacquering, from waste air. A specific micro-flora (mixture of Bacillus for ethanol and two pseudomonas species for toluene) able to degrade ethanol and toluene, was jimed on a packed bed of particles of commercial peat intermittently humidified by a nutrient solution necessary for the suroival of the micro-organisms.In the experiments, polluted gas was fed upwara3 through the bed and pbysical parameten: moisture content ofpat; humidity of aic temperature; pressure drop; inlevoutlet concentration of gas and microbialpopulation were measured regularly in order to check the performance of the biodegradation process.These experiments showed good pe~ormance and good stability of the biofilter over time.
Experiments during a period of 93 days are reported on the treatment of waste air containing toluene vapor using a laboratory scale biofilter system packed with peat inoculated with specific florae (Pseudomonas type) and intermittently humidified with a nutrient solution necessary for the survival of the micro-organisms. Design and operation parameters were regularly measured in order to check the performance of the biodegradation process.Under
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.