Removal of p-xylene from an air stream in a hybrid biofilter

ArticleinJournal of Hazardous Materials 136(2):288-95 · September 2006with8 Reads
DOI: 10.1016/j.jhazmat.2005.12.017 · Source: PubMed
Abstract
Biofiltration of an air stream containing p-xylene has been studied in a laboratory hybrid biofilter packed with a mixture of mature pig compost, forest soil and the packing material which was made of polyethylene (PE) and used in the moving bed biological reactor (MBBR) in wastewater treatment. Three flow rates, 9.17, 19.87 and 40.66 m(3)m(-2)h(-1), were investigated for p-xylene inlet concentration ranging from 0.1 to 3.3 g m(-3). A high elimination capacity of 80 g m(-3)h(-1) corresponding to removal efficiency of 96% was obtained at a flow rate of 9.17 m(3)m(-2)h(-1) (empty bed residence time of 132 s). At a flow rate of 40.66 m(3)m(-2)h(-1) (empty bed residence time of 30s), the maximum elimination capacity for p-xylene was 40 g m(-3)h(-1) and removal efficiencies were in the range of 47-100%. The production of carbon dioxide (P(CO(2))) is proportional to elimination capacity (EC) and the linear relation was formulated as P(CO(2))=1.65EC+15.58. Stable pH values ranging from 6.3 to 7.6 and low pressure drop values less than 0.2 cm H(2)O (19.6 Pa) of packing media in compost-based biofilter of hybrid biofilter were observed, which avoided acidification and compaction of packing media and sustained the activity of microorganism populations.
    • "According to their study, linear fits to experimental data was made, and mass-ratios of ethylbenzene and toluene were 1.36 and 2.84, respectively. Cheng Wu et al., 2006). "
    [Show abstract] [Hide abstract] ABSTRACT: A lab-scale biofilter packed with mixed packing materials was used for degradation of the toluene. Different empty bed residence times, 148.3, 74.2 and 49.4 s, were tested for inlet concentration ranging from 0.2 to 1.2 g/m 3 . The maximum elimination capacity of 36.0 g/(m 3 h) occurred at an inlet loading rate of 45.9 g/(m 3 h). The contribution of the lower layer was higher than other layers and always had the highest elimination capacity. The carbon dioxide production rate and distribution of micro-organisms followed toluene elimination capacities. The results of this study indicated that mixed packing materials could be considered as a potential biofilter carrier, with low pressure drop (less than 84.9 Pa/m), for treating air streams containing VOCs.
    Full-text · Article · May 2016
    • "Several possible combinations of biological reactors can be found in literature. Operational advantages may be obtained as a result of integrating two bioreactors , e.g., biofilter-biofilter,6789 TBR-biofilter(s),1011121314 biofilter-TBR, [15] mixing reactor-TBR, [16] and bioscrub- ber-biofilter. [17] In such integrated reactors, the expected TBR positioning is in front of BF, due to the high water usage in the TBR. "
    [Show abstract] [Hide abstract] ABSTRACT: Performance of a two-stage biofiltration system was investigated for removal of styrene-acetone mixtures. High steady-state acetone loadings (above Cin(Ac) = 0.5 g.m(-3) corresponding to the loadings > 34.5 g.m(-3).h(-1)) resulted in a significant inhibition of the system's performance in both acetone and styrene removal. This inhibition was shown to result from the acetone accumulation within the upstream trickle-bed bioreactor (TBR) circulating mineral medium, which was observed by direct chromatographic measurements. Placing a biofilter (BF) downstream to this TBR overcomes the inhibition as long as the biofilter has a sufficient bed height. A different kind of inhibition of styrene biodegradation was observed within the biofilter at very high acetone loadings (above Cin(Ac) = 1.1 g.m(-3) or 76 g.m(-3).h(-1) loading). In addition to steady-state measurements, dynamic tests confirmed that the reactor overloading can be readily overcome, once the accumulated acetone in the TBR fluids is degraded. No sizable metabolite accumulation in the medium was observed for either TBR or BF. Analyses of the biodegradation activities of microbial isolates from the biofilm corroborated the trends observed for the two-stage biofiltration system, particularly the occurrence of an inhibition threshold by excess acetone.
    Full-text · Article · Sep 2015
    • "In addition, all bacterial system involves production of acids as their intermediate or end products. Acidification of packing media can reduce the efficiency of biofiltration [1].The variation of pH of the filter media was recorded during the biofiltration studies and plotted inFig. 8.The pH varied in the range of 6.4 -7.4 during the entire period and no noticeable change in the state and structure of filter media was noted. "
    [Show abstract] [Hide abstract] ABSTRACT: The performance of a laboratory scale biofilter using date palm tree barks as packing material was studied to remove xylene. Experiments were performed by subjecting the biofilter to different xylene inlet loading rates(3.0-214.0 g/m3 h) and flow rates (0.06, 0.09 and 0.012 m3/h). Removal efficiencies greater than 90% were achieved in the inlet xylene concentration range of 0.1-3.2 g/m3. The elimination capacity was found to vary linearly with inlet loading rates.The concentration profiles were studied axially during the biofiltration experiments and the lower parts of the biofilter removed a significant part of inlet xylene. The temperature and pH variations were recorded during the entire biofiltration studies. The carbon dioxide production rate was related to elimination capacity by the equation CPR = 1.81 EC + 14.12. The Michaelis-Menten type model kinetic constants for the biofiltration of xylene were evaluated as maximum elimination capacity, ECmax = 178.57g/m3h and saturation constant Ks =1.232 g/m3.The stability of the biomass inside the biofilter was found to be good by subjecting the biofilter to shock load conditions.
    Full-text · Article · Feb 2015 · Journal of Environmental Science and Health Part A Toxic/Hazardous Substances & Environmental Engineering
Show more

  • undefined · undefined
  • undefined · undefined
  • undefined · undefined

Recommended publications

Discover more