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1.
The removal of toluene from an experimental gas-stream was studied in an industrial biofilter filled with poplar wood bark. Toluene degradation, approximately 85% through the operating period, resulted in low levels of toluene in the off-gas effluent. For a toluene load of 6.7 g m-3 h-1 the elimination capacity of the biofilter was found to be 6.0 g m-3 h-1. Toluene removal was due to biodegradative activity of microorganisms in the filter bed; the most probable number counts of toluene degraders increased from 2.4×102 to 6.4×107 MPN/g dry packing material in about seven months of air-toluene supply. The degradative capacity of a Burkholderia (Pseudomonas) cepacia strain, isolated from the biofilter material, as an example of the effectiveness of microbial toluence removal was tested in batch culture. The microorganism degraded completely 250 ppm of toluence supplied as sole carbon source in 24 hours. The high performance demonstrated for a long period and the mechanical and physico-chemical stability of the biofilter favour its use in industrial full-scale off-gas control. 相似文献
2.
A 2-l (1-l working volume) two-phase partitioning bioreactor (TPPB) was used as an integrated scrubber/bioreactor in which the removal and destruction of benzene from a gas stream was achieved by the reactor's organic/aqueous liquid contents. The organic solvent used to trap benzene was n-hexadecane, and degradation of benzene was achieved in the aqueous phase using the bacterium Alcaligenes xylosoxidans Y234. A gas stream with a benzene concentration of 340 mg l(-1) at a flow rate of 0.414 l h(-1) was delivered to the system at a loading capacity of 140 g m(-3) h(-1), and an elimination capacity of 133 g m(-3 )h(-1) was achieved (the volume in this term is the total liquid volume of the TPPB). This elimination capacity is between 3 and 13 times greater than any benzene elimination achieved by biofiltration, a competing biological air treatment strategy. It was also determined that the evaluation of TPPB performance in terms of elimination capacity should include the cell mass present in the system, as this is a readily controllable quantity. A specific benzene utilization rate of 0.57 g benzene (g cells)(-1) h(-1) was experimentally determined in a bioreactor with a cell concentration that varied dynamically between 0.2 and 1 g l(-1). If it assumed that this specific benzene utilization rate (0.57 g g(-1) h(-1)) is independent of cell concentration, then a TPPB operated at high cell concentrations could potentially achieve elimination capacities several hundred times greater than those obtained with biofilters. 相似文献
3.
Biofiltration of waste gases with the fungi Exophiala oligosperma and Paecilomyces variotii 总被引:1,自引:0,他引:1
Two biofilters fed toluene-polluted air were inoculated with new fungal isolates of either Exophiala oligosperma or Paecilomyces variotii, while a third bioreactor was inoculated with a defined consortium composed of both fungi and a co-culture of a Pseudomonas strain and a Bacillus strain. Elimination capacities of 77 g m–3 h–1 and 55 g m–3 h–1 were reached in the fungal biofilters (with removal efficiencies exceeding 99%) in the case of, respectively, E. oligosperma and Paecilomyces variotii when feeding air with a relative humidity (RH) of 85%. The inoculated fungal strains remained the single dominant populations throughout the experiment. Conversely, in the biofilter inoculated with the bacterial–fungal consortium, the bacteria were gradually overgrown by the fungi, reaching a maximum elimination capacity around 77 g m–3 h–1. Determination of carbon dioxide concentrations both in batch assays and in biofiltration studies suggested the near complete mineralization of toluene. The non-linear toluene removal along the height of the biofilters resulted in local elimination capacities of up to 170 g m–3 h–1 and 94 g m–3 h–1 in the reactors inoculated, respectively, with E. oligosperma and P. variotii. Further studies with the most efficient strain, E. oligosperma, showed that the performance was highly dependent on the RH of the air and the pH of the nutrient solution. At a constant 85% RH, the maximum elimination capacity either dropped to 48.7 g m–3 h–1 or increased to 95.6 g m–3 h–1, respectively, when modifying the pH of the nutrient solution from 5.9 to either 4.5 or 7.5. The optimal conditions were 100% RH and pH 7.5, which allowed a maximum elimination capacity of 164.4 g m–3 h–1 under steady-state conditions, with near-complete toluene degradation. 相似文献
4.
Mutafov S Angelova B Schmauder HP Avramova T Boyadjieva L 《Applied microbiology and biotechnology》2004,65(2):228-234
The applicability of a recently published modification of the chemostat, named titrostat, for microbial continuous-flow purification of toluene-contaminated air is discussed. This article describes the operative range and the toluene elimination efficiency of a 2-l titrostat running with a mixed bacterial culture dominated by two Acinetobacter species: A. calcoaceticus and A. radioresistens. The study focuses on the kinetics and stoichiometry of the process. Special attention is paid to the peculiarities of toluene as an unconventional growth substrate having high carbon and energy content. Removal productivity as high as 2.24 g l–1 h–1 with 99.9% elimination efficiency was observed at air flow rate 60 l h–1, temperature 32°C, pH 6.2, toluene concentration in the inlet air 37.4 mg l–1 and titrant solution containing NH3 at 1.87 g l–1. The maximum biomass yield from assimilated toluene, Y
s
m=0.880±0.011, and a rate of substrate expenditures for cell maintenance, m
s=0.022±0.002 h–1, were estimated. 相似文献
5.
Prabhat Kumar Thakur Anil Kumar Mathur Shashi Bala Gautam Chandrajit Balomajumder Rahul 《Bioremediation Journal》2013,17(1):61-70
ABSTRACT A laboratory-scale biofilter unit packed with a mixture of compost, sugarcane bagasse, and granulated activated carbon (GAC) in the ratio of 55:30:15 by weight was used for a biofiltration study of air stream containing benzene, toluene, ethylbenzene, and o-xylene (BTEX). The effect of superficial velocity on mass transfer coefficient for the packing was studied by maintaining gas flow rates of 3, 4, 5, 6, and 8 L min?1 for inlet concentrations of 0.1, 0.4, and 0.8 g m?3 for each of benzene, toluene, ethylbenzene, and o-xylene. The maximum elimination capacity was found to be 20.92, 22.72, 20.73, and 18.94 g m?3 h?1 for BTEX, respectively, for stated flow rates. Removal efficiency of BTEX decreased from 99% to 71% for increasing inlet concentration from 0.1 to 0.8 g m?3. Gas film mass transfer coefficient predicted by modified Onda's equation was within ±10% of the experimental values. 相似文献
6.
This investigation characterizes a novel 11 L airlift two‐phase partitioning bioreactor (TPPB) for the treatment of gases contaminated with a mixture of benzene, toluene, ethylbenzene, and o‐xylene (BTEX). The application of the TPPB technology in an airlift bioreactor configuration provides a novel technology that reduces energy intensity relative to traditional stirred tank TPPB configurations. The addition of a solid second phase of silicone rubber beads (10%, v/v) or of a liquid second phase of silicone oil (10%, v/v) resulted in enhanced performance of the airlift bioreactor relative to the single phase case, with 20% more BTEX being removed from the gas phase during an imposed transient loading. During a 4 h loading step change of three times the nominal loading (60 g m?3 h?1), overall removal efficiencies for the airlift TPPBs containing a liquid or solid phase remained above 75%, whereas the single phase airlift had an overall removal efficiency of 47.1%. The airlift TPPB containing a silicone rubber second phase was further characterized by testing performance during steady‐state operation over a range of loadings and inlet gas flow rates in the form of a 32 factorial experimental design. Optimal operating conditions that avoid oxygen limitations and that still have a slow enough gas flow rate for sufficient BTEX transfer from the gas phase to the working volume are identified. The novel solid–liquid airlift TPPB reduces energy inputs relative to stirred tank designs while being able to eliminate large amounts of BTEX during both steady‐state and fluctuating loading conditions. Biotechnol. Bioeng. 2009;103: 1077–1086. © 2009 Wiley Periodicals, Inc. 相似文献
7.
Feliu Sempere Carmen Gabaldón Vicente Martínez‐Soria Josep Manuel Penya‐roja Francisco Javier Álvarez‐Hornos 《Engineering in Life Science》2009,9(4):317-323
The removal of a 1:1 by weight mixture of ethanol and ethyl acetate was studied in a gas phase biotrickling filter running under conditions that simulated industrial emissions from the flexographic sector, i.e. discontinuous loading (twelve hours per day and five days per week) and oscillating concentration of the inlet stream. Three sets of experimental conditions were tested in which empty‐bed residence time varied from 60 to 25 s (inlet loads from 50 to 90 g C m?3 h?1). The biotrickling filter reached a maximum elimination capacity of 48.5 g C m?3 h?1 (removal efficiency=68.9%) for an empty‐bed residence time of 40 s. A decrease in the residence time from 40 to 25 s adversely affected the elimination capacity (40.3 g C m?3 h?1, removal efficiency=46.6%). For the three tested residence times, outlet concentrations during pollutant feeding were above 100 mg C m?3 (EU legal limit for flexographic facilities). Then an activated carbon prefilter was installed to buffer the fluctuating concentration, enabling a more stable operation. The desorbed pollutant from the activated carbon during non‐feeding hours also served as an extra source of substrate, avoiding severe starvation. The use of the activated carbon prefilter with a volume 25 times lower than that of the bioreactor was shown to reach an average outlet emission concentration lower than 50 mg C m?3 operating the biotrickling filter at an empty‐bed residence time of 40 s, with a maximum elimination capacity of 59.6 g C m?3 h?1 (removal efficiency=92.0%). 相似文献
8.
Simultaneous removal of benzene, toluene and xylenes mixture by a constructed microbial consortium during biofiltration 总被引:1,自引:0,他引:1
A bacterial consortium with complementary metabolic capabilities was formulated and specific removal rates were 0.14, 0.35, 0.04, and 0.39 h–1 for benzene, toluene, o-xylene, and m,p-xylene, respectively. When immobilized on a porous peat moss biofilter, removal of all five (= BTX) components was observed with rates of 1.8–15.4 g m–3 filter bed h–1. Elimination capacities with respect to the inlet gas concentrations of BTX and airflow rates showed diffusive regimes in the tested concentration range of (0.1–5.3 g m–3) and airflow (0.55–1.82 m3 m–2 h–1) except for o-xylene which reached its critical gas concentration at 0.3 g m–3. 相似文献
9.
A two-phase aqueous/organic partitioning bioreactor scheme was used to degrade mixtures of toluene and benzene, and toluene
and p-xylene, using simultaneous and sequential feeding strategies. The aqueous phase of the partitioning bioreactor contained
Pseudomonas sp. ATCC 55595, an organism able to degrade benzene, toluene and p-xylene simultaneously. An industrial grade of oleyl alcohol served as the organic phase. In each experiment, the organic
phase of the bioreactor was loaded with 10.15 g toluene, and either 2.0 g benzene or 2.1 g p-xylene. The resulting aqueous phase concentrations were 50 mg/l, 25 mg/l and 8 mg/l toluene, benzene and p-xylene respectively. The simultaneous fermentation of benzene and toluene consumed these compounds at volumetric rates of
0.024 g l−1 h−1 and 0.067 g l−1 h−1, respectively. The simultaneous fermentation of toluene and p-xylene consumed these xenobiotics at volumetric rates of 0.066 g l−1 h−1 and 0.018 g l−1 h−1, respectively. A sequential feeding strategy was employed in which toluene was added initially, but the benzene or p-xylene aliquot was added only after the cells had consumed half of the initial toluene concentration. This strategy was shown
to improve overall degradation rates, and to reduce the stress on the microorganisms. In the sequential fermentation of benzene
and toluene, the volumetric degradation rates were 0.056 g l−1 h−1 and 0.079 g l−1 h−1, respectively. In the toluene/p-xylene sequential fermentation, the initial toluene load was consumed before the p-xylene aliquot was consumed. After 12 h in which no p-xylene degradation was observed, a 4.0-g toluene aliquot was added, and p-xylene degradation resumed. Excluding that 12-h period, the microbes consumed toluene and p-xylene at volumetric rates of 0.074 g l−1 h−1 and 0.025 g l−1 h−1, respectively. Oxygen limitation occurred in all fermentations during the rapid growth phase.
Received: 16 November 1998 / Received revision: 29 March 1999 / Accepted: 9 April 1999 相似文献
10.
Removal of toluene in waste gases using a biological trickling filter 总被引:12,自引:0,他引:12
The removal of toluene from waste gas was studied in a trickling biofilter. A high level of water recirculation (4.7 m h–1) was maintained in order to keep the liquid phase concentration constant and to achieve a high degree of wetting. For loads in the range from 6 to 150 g m–3 h–1 the maximum volumetric removal rate (elimination capacity) was 35±10 g m–3 h–1, corresponding to a zero order removal rate of 0.11±0.03 g m–2 h–1 per unit of nominal surface area. The surface removal was zero order above the liquid phase concentrations of approximately 1.0 g m–3, corresponding to inlet gas concentrations above 0.7–0.8 g m–3. Below this concentration the surface removal was roughly of first order. The magnitude of the first order surface removal rate constant, k1A
, was estimated to be 0.08–0.27 m h–1 (k1A
a=24–86 h–1). Near-equilibrium conditions existed in the gas effluent, so mass transfer from gas to liquid was obviously relatively fast compared to the biological degradation. An analytical model based on a constant liquid phase concentration through the trickling filter column predicts the effluent gas concentration and the liquid phase concentration for a first and a zero order surface removal. The experimental results were in reasonable agreement with a very simple model valid for conditions with an overall removal governed by the biological degradation and independent of the gas/liquid mass transfer. The overall liquid mass transfer coefficient, KLa, was found to be a factor 6 higher in the system with biofilm compared to the system without. The difference may be explained by: 1. Difference in the wetting of the packing material, 2. Mass transfer occurring directly from the gas phase to the biofilm, and 3. Enlarged contact area between the gas phase and the biofilm due to a rough biofilm surface. 相似文献
11.
Hee Wook Ryu So Jong Kim Kyung-Suk Cho Tae Ho Lee 《Biotechnology and Bioprocess Engineering》2008,13(3):360-365
In the present study, toluene elimination in the polyurethane (PU) biofilter during long-term (145 day) operation was characterized,
and assessed the effects of changing the inlet loading and space velocity (SV). A very high elimination capacity of 3.7 kg·m−3·h−1 was obtained at an inlet loading of 4.0 kg·m–3·h−1 (inlet toluene concentration of 900 ppmv at a SV of 1,040 h−1). Backwashing with irrigation and compressed air allowed maintenance of a pressure drop of < 80 mm H2O·m−1-filter at an SV of 830 h−1 and an elimination efficiency of > 90% during the 145 day of operation. In conclusion, the PU biofilter can overcome the
problems of clogging caused by excess biomass growth and of low treatment capacities of conventional biofilters. 相似文献
12.
Several biofilters and biotrickling filters were used for the treatment of a mixture of formaldehyde and methanol; and their efficiencies were compared. Results obtained with three different inert filter bed materials (lava rock, perlite, activated carbon) suggested that the packing material had only little influence on the performance. The best results were obtained in a biotrickling filter packed with lava rock and fed a nutrient solution that was renewed weekly. A maximum formaldehyde elimination capacity of 180 g m–3 h–1 was reached, while the methanol elimination capacity rose occasionally to more than 600 g m–3 h–1. Formaldehyde degradation was affected by the inlet methanol concentration. Several combinations of load vs empty bed residence time (EBRTs of 71.9, 46.5, 30.0, 20.7 s) were studied, reaching a formaldehyde elimination capacity of 112 g m–3 h–1 with about 80% removal efficiency at the lowest EBRT (20.7 s). 相似文献
13.
Removal and destruction of high concentrations of gaseous toluene in a two-phase partitioning bioreactor by Alcaligenes xylosoxidans 总被引:1,自引:0,他引:1
A two-phase bioreactor consisting of hexadecane dispersed in an aqueous, cell-containing medium (organic fraction = 0.33) was used to trap toluene vapours from an air stream. The affinity for toluene by the solvent resulted in high efficiency of removal and transfer to the aqueous phase based on equilibrium transfer. The system was readily able to handle a loading capacity of 748 mg l–1 h–1 at a toluene degradation efficiency of greater than 98%. 相似文献
14.
Microbial response and elimination capacity in biofilters subjected to high toluene loadings 总被引:4,自引:0,他引:4
Elimination capacity (EC) is frequently used as a performance and design criterion for vapor-phase biofilters without further
verification of the microbial quantity and activity. This study was conducted to investigate how biofilters respond to high
pollutant loadings and ultimately how this affects the EC of the biofilter. Two identical laboratory-scale biofilters were
maintained at an initial toluene loading rate of 46 g m−3 h−1 for a period of 24 days. After the initial biofilm development stage, the loading rates were increased to 91 g m−3 h−1 and 137 g m−3 h−1, respectively. Following a short period of pseudo-steady state, toluene removal efficiencies rapidly declined in both biofilters,
with a concurrent decline in both critical and maximum ECs. The decline was mainly due to deterioration in the biodegradation
activity of the biofilm and a decline in the toluene-degrading bacterial population within the biofilm phase. The findings
imply that high toluene loadings accelerated the deterioration in overall performance due to a rapid accumulation of inactive
biomass. As a result, care must be used when relying on EC values for biofilter design and operational purposes, since the
values do not appropriately reflect the temporal changes in biodegradation activity and active biomass quantities that can
occur in biofilters subjected to high inlet loadings. 相似文献
15.
Microbial Succession in a Compost-packed Biofilter Treating
Benzene-contaminated Air 总被引:2,自引:0,他引:2
Borin S Marzorati M Brusetti L Zilli M Cherif H Hassen A Converti A Sorlini C Daffonchio D 《Biodegradation》2006,17(2):79-89
Air artificially contaminated with increasing concentrations of benzene was treated in a laboratory scale compost-packed biofilter
for 240 days with a removal efficiency of 81–100%. The bacterial community in the packing material (PM) at different heights
of the biofilter was analysed every 60 days. Bacterial plate counts and ribosomal intergenic spacer analysis (RISA) of the
isolated strains showed that the number of cultivable aerobic heterotrophic bacteria and the species diversity increased with
benzene availability. Identification of the isolated species and the main bands in denaturing gradient gel electrophoresis
(DGGE) profiles from total compost DNA during the treatment revealed that, at a relatively low volumetric benzene load (1.2≤VBL≤6.4 g m−3
PM h−1), besides low G+C Gram positive bacteria, originally present in the packing compost, bacteroidetes and β- and γ-proteobacteria
became detectable in the colonising population. At the VBL value (24.8 g m−3
PM h−1) ensuring the maximum elimination capacity of the biofilter (20.1 g m−3
PM h−1), strains affiliated to the genus Rhodococcus dominated the microflora, followed by β-proteobacteria comprising the genera Bordetella and Neisseria. Under these conditions, more than 35% of the isolated strains were able to grow on benzene as the sole carbon source. Comparison
of DGGE and automated RISA profiles of the total community and isolated strains showed that a complex bacterial succession
occurred in the reactor in response to the increasing concentrations of the pollutant and that cultivable bacteria played
a major role in benzene degradation under the adopted conditions. 相似文献
16.
Active compost biofiltration of toluene 总被引:5,自引:0,他引:5
Composting of leaves and alfalfa (i.e. active compost) was used for thebiofiltration of toluene-contaminated air in a 6-L biofilter (initial bedheight: 180 mm). During the thermophilic phase (45 to 55 °C), toluenebiodegradation rates reached 110 gtoluene.m-3.h-1 at an inlet concentration ofabout 5 g.m-3.h-1 and a gas residence time of 90 seconds. Thehighest rates were obtained late in the thermophilic phase suggesting amicrobial adaptation was occurring. Biodegradation rates decreased rapidly(50% in 48h) in the cooling stage. Under mesophilic conditions, themaximum biodegradation rates that could be obtained by increasing the inlettoluene concentration were near 89 gtoluene.m-3.h-1 which issimilar to that reported in the literature for mature compost biofilters. Novolatile by-product was detected by gas chromatography. Mineralization of14C-toluene and benzene showed that they were completelydegraded into CO2 and H2O under boththermophilic and mesophilic conditions. Bacteria isolated from latemesophilic stage had the capacity to degrade all BTEX compounds but were notable to transform chlorinated compounds. No organisms were isolated whichcould use toluene as their sole source of carbon and energy at 50 °C.Active compost biofiltration should be an excellent process for thetreatment of gaseous BTEX by biofiltration. This is the first report ofthermophilic biofiltration of toluene. 相似文献
17.
Evaluation of the performance of structured mixed packing and inert packing materials in toluene biotrickle-filtration 总被引:1,自引:0,他引:1
Duanfang Sun Jianjun Li Taicheng An Meiying Xu Guoping Sun Jun Guo 《Biotechnology and Bioprocess Engineering》2011,16(5):1009-1018
Packing materials play a key role in waste gas treatment. Organic and inert packing materials have their disadvantages, which
may be minimized by mixed packing. In this study, various operating conditions were applied to evaluate the performance of
structured mixed packing and inert packing materials in toluene biotricklefiltration. Four biotrickle filters were packed
with structured mixed packing materials, namely, ceramic pall rings, ceramic rashig rings, and lava rock. Their toluene removal
capacity was studied for 217 day using a laboratory-scale reaction under various operating conditions. The key elimination
capacity (removal efficiency > 95%) ranking of the biotrickle filters was as follows: Structured mixed packing (306.20 ± 7.90
g/m3/h) > pall ring (156.71 ± 7.84 g/m3/h) > rashig ring (153.31 ± 6.14 g/m3/h) > lava rock (150.32 ± 9.19 g/m3/h). The structured mixed packing and inert packing resulted in excellent toluene-degrading biofilter performance under long-term
operation. The structured mixed packing provided a more rapid startup rate and better process robustness than the inert packing
did. The biotrickle filter with mixed packing materials had a high elimination capacity which makes it suitable for various
real-life applications, whereas the capability of the inert packing material was more suitable for treating a steady low toluene
load. 相似文献
18.
Benzene, toluene, ethylbenzene and xylene (BTEX) substrate interactions for a mesophilic (25°C) and thermophilic (50°C) toluene-acclimatized composted pine bark biofilter were investigated. Toluene, benzene, ethylbenzene, o-xylene, m-xylene and p-xylene removal efficiencies, both individually and in paired mixtures with toluene (1:1 ratio), were determined at a total loading rate of 18.1 g m–3 h–1 and retention time ranges of 0.5–3.0 min and 0.6–3.8 min for mesophilic and thermophilic biofilters, respectively. Overall, toluene degradation rates under mesophilic conditions were superior to degradation rates of individual BEX compounds. With the exception of p-xylene, higher removal efficiencies were achieved for individual BEX compounds compared to toluene under thermophilic conditions. Overall BEX compound degradation under mesophilic conditions was ranked as ethylbenzene >benzene >o-xylene >m-xylene >p-xylene. Under thermophilic conditions overall BEX compound degradation was ranked as benzene >o-xylene >ethylbenzene >m-xylene >p-xylene. With the exception of o-xylene, the presence of toluene in paired mixtures with BEX compounds resulted in enhanced removal efficiencies of BEX compounds, under both mesophilic and thermophilic conditions. A substrate interaction index was calculated to compare removal efficiencies at a retention time of 0.8 min (50 s). A reduction in toluene removal efficiencies (negative interaction) in the presence of individual BEX compounds was observed under mesophilic conditions, while enhanced toluene removal efficiency was achieved in the presence of other BEX compounds, with the exception of p-xylene under thermophilic conditions. 相似文献
19.
A mixed culture was utilized to evaluate methyl tert-butyl ether (MTBE) removal under various conditions and to isolate a MTBE-degrading pure culture. The results showed that
high MTBE removal efficiencies can be reached even in the presence of other substrates. The biodegradation sequence of the
target compounds by the mixed culture, in order of removal rate, was toluene, ethyl benzene, p-xylene, benzene, MTBE, ethyl ether, tert-amyl methyl ether, and ethyl tert-butyl ether. In addition, preincubation of the mixed cultures with benzene and toluene showed no negative effect on MTBE
removal; on the contrary, it could even increase the degradation rate of MTBE. The kinetic behavior showed that the maximum
specific growth rate and the saturation constant of the mixed culture degrading MTBE are 0.000778 h−1 and 0.029 mg l−1, respectively. However, a high MTBE concentration (60 mg l−1) was slightly inhibiting to the growth of the mixed culture. The pure culture isolated from the enrichments in the bubble-air
bioreactor showed better efficiency in MTBE removal than the mixed culture; whereas, tert-butyl alcohol was formed as a metabolic intermediate during the breakdown of MTBE. 相似文献
20.
Gallastegui G Avalos Ramirez A Elías A Jones JP Heitz M 《Bioresource technology》2011,102(17):7657-7665
Interactions of toluene and p-xylene in air treatment biofilters packed with an inert filter media were studied. The effect of the inlet load of toluene, p-xylene and mixtures of both compounds on the biodegradation rate was analyzed in three lab-scale biofilters. A maximum elimination capacity (EC) of 26.5 and 40.3 g C m−3 h−1 for an inlet load (IL) of 65.6 and 57.8 g C m−3 h−1 was obtained for p-xylene and toluene biofilters, respectively. Inhibition of p-xylene biodegradation by the presence of toluene took place when the mixture was treated, whereas the presence of p-xylene had an enhancing effect on the toluene removal efficiency. Specific growth rates (μ) from 0.019 to 0.068 h−1 were calculated in the mixed biofilter, where the highest values were similar to mixtures with lower p-xylene levels (ILp-Xyl 8.84 ± 0.29 g C m−3 h−1). Michaelis-Menten and Haldane type models were fitted to experimental EC for p-xylene and toluene biofilters, respectively. 相似文献