Enhanced styrene removal in a two-phase partitioning bioreactor operated as a biotrickling filter: Towards full-scale applications

Abstract

Styrene vapor abatement was investigated in a two-phase partitioning bioreactor operated as a biotrickling filter (TPPB-BTF). The removal performance of the TPPB-BTF was simultaneously compared with a conventional BTF, which served as a control. Industrialgrade silicone oil was used as the non-aqueous phase in the TPPB-BTF due to its high affinity for styrene. Both bioreactors were operated at styrene inlet concentrations ranging from 55 to 323 mg C m-3 and empty bed residence times (EBRT) of 15-30 s, corresponding to pollutant loading rates of 13-77 g C m-3 h-1. Both bioreactors exhibited styrene removal efficiencies (REs) higher than 90% at an EBRT of 30 s. Nevertheless, the TPPB-BTF showed a superior removal performance than that recorded in the control BTF at EBRTs shorter than 30 s. REs of 89%, 84% and 57% were recorded in the TPPB-BTF at EBRT of 15 s and loading rates of 13, 22 and 77 g C m-3 h-1 , respectively, while the control BTF supported removal efficiencies of 64%, 42% and 18-42% under the same experimental conditions. The resilience and robustness of the TPPB-BTF over styrene shock loadings and transient inlet concentration was also confirmed, the TPPB-BTF being able to recover a stable RE of 89% one day after such operation disturbances. The potential of the TPPB-BTF towards full scale applications was also critically discussed based on the experimental determination of silicone oil loses through aqueous phase renewal, which accounted for 0.4% of the initial volume of oil added to the TPPB-BTF after 87 days of operation.

Experiments and modelling of a biotrickling filter (BTF) for removal of styrene from airstreams

“…The system of Eqs. (12)- (15) and (24), (25), with boundary conditions (17)(18)(19)(20)(21), constitute the mathematical description of the process of biopurification of air containing styrene (moderately hydrophobic VOC) carried out in a BTF.…”

“…In order to estimate the styrene and oxygen concentration profiles along the bed length the boundary value problems defined by the system of Eqs. (12)- (15) and (24), (25), subject to boundary conditions (17)- (21), have to be solved. The integration of this system of differential equations demands knowledge of the values of derivatives dS i dΘ for Θ = 0.…”

“…In the literature one can find numerous studies whose authors examined the process of biopurification of air from styrene in laboratory‐scale biofilters (BF) and biotrickling filters (BTF) (recently). Pilot studies on the removal of styrene from the air are still scarce thus making its industrial implementation difficult.…”

“…5 Moreover styrene, a moderately hydrophobic compound, is readily biodegradable and can be used as a model substance for studying microbial degradation of aromatic compounds. 2 In the literature one can find numerous studies whose authors examined the process of biopurification of air from styrene in laboratory-scale biofilters (BF) and biotrickling filters (BTF) (recently [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Pilot studies on the removal of styrene from the air are still scarce 6,13,20 thus making its industrial implementation difficult.…”

“…Attempts to increase the efficiency of the process of biopurification of air are made by the addition of silicone oil as a non-aqueous phase (NAP) to the liquid trickling over the packing of BTF; in this way the mass transfer of hydrophobic compounds from gas to liquid phase was enhanced, 10,12,15,19,24 or by using integrated UV-BTF systems. 9,13 Rene et al [17][18][19] studied removal of styrene using a newly isolated fungus Sporothrix veriecibatus.…”