title: Biological treatment characteristics of benzene and toluene in a biofilter packed with cylindrical activated carbon.
abstract: The biodegradation of toluene and benzene in a biofilter using cylindrical activated carbon as the filler materials was studied. Three gas low rates, i.e. 0.25, 0.50 and 0.75 m3/h, corresponding to empty bed gas residence of 75, 37.5 and 25 s, respectively, and total organic load lower than 400 g/m3 x h were tested. The biofilter proved to be highly efficient in biodegradation of toluene and benzene, and toluene was more easily degraded than benzene. When each inlet load was lower than 150 g/m3 x h, removal rate increased with inlet load and reached a maximum, which was 150 and 120 g/m(-3) x h for toluene and benzene, respectively. For inlet load higher than the maximum removal capacity conditions, the removal rate decreased with inlet load. Carbon dioxide concentration profile through the biofilter revealed that the mass ratios of carbon dioxide produced to the toluene and benzene removed were 2.15 g(CO2)/g(toluene) and 1.67 g(CO2)/g(benzene), which furthermore, confirmed the biodegradation performance in biofilter. The observation of biotic community demonstrated that the microbes consisted of bacillus, spore bacillus and fungi, of which the spore bacillus was dominant.
authors.affiliation: ESPC, Department of Environment Science and Engineering, Tsinghua University, Beijing 100084, China.
authors.forename: G W
authors.initials: GW
authors.lastname: Li
authors.forename: H Y
authors.initials: HY
authors.lastname: Hu
authors.forename: J M
authors.initials: JM
authors.lastname: Hao
authors.forename: H Q
authors.initials: HQ
authors.lastname: Zhang
mesh_terms: D000327:Adsorption; D001419:Bacteria; D001554:Benzene / Q000378:metabolism*; D001673:Biodegradation, Environmental; D018533:Biomass; D019149:Bioreactors; D002244:Carbon; D005374:Filtration; D014050:Toluene / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism*; D018508:Water Purification / Q000379:methods*
chemical_list: D014874:Water Pollutants, Chemical; D014050:Toluene; D002244:Carbon; D001554:Benzene