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Improved peroxidase-mediated biodegradation of toluene vapors in the moving-bed activated sludge diffusion (MASD) process using biosurfactant-generating biomass stimulated with H2O2

Aghayani, Ehsan, Moussavi, Gholamreza, Naddafi, Kazem
Journal of hazardous materials 2019 v.361 pp. 259-266
Pseudomonas, activated sludge, air, air flow, air pollution, bacteria, biodegradation, biomass, biosurfactants, hydrogen peroxide, mineralization, peroxidase, toluene, vapors
Two strategies were attempted to improve the biodegradation and mineralization of toluene vapors in the activated sludge diffusion (ASD) process using biosurfactant-generating Pseudomonas spp. and Bacillus spp. mixture. Different operational parameters including toluene concentration, superficial air velocity, biomass concentration, moving-media insertion and H2O2 were evaluated on toluene removal in the ASD process within 550 days of operation. It was found that complete biodegradation and 79.8% mineralization of toluene vapors at inlet loading rate of 144 g/m³.h could be achieved in the ASD process by inserting moving media (MASD) at a volume ratio of 20% along with stimulation of bacteria with H2O2. The concentration of biosurfactant and peroxidase generated in the integrated process (H2O2-stimulated MASD reactor) was 3.7 and 2.5 times of that in the conventional ASD process. The maximum toluene elimination capacity obtained in the H2O2- stimulated MASD process was 285 g/m³.h at an inlet loading rate of around 430 g/m³.h. Accordingly, H2O2-mediated MASD process could be a promising technique for efficient biodegradation and mineralization of aromatic hydrocarbons in the contaminated air streams.