biofilter
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A 2:1 (w/w) mixture of styrene (STY) and acetone (AC) was subjected to lab-scale biofiltration under varied loading in both a trickle bed reactor (TBR) and biofilter (BF) to investigate substrate interactions and determine the limits of biofiltration efficiency of typical binary air pollutant mixtures containing both hydrophobic and polar components. A comparison of the STY/AC mixture degradation in the TBR and BF revealed higher pollutant removal efficiencies and degradation rates in the TBR, with the pollutant concentrations increasing up to the overloading limit. The maximum styrene degradation rates were 12 and 8 gc m(-3) h(-1) for the TBR and BF, respectively. However, the order of performance switched in favor of the BF when the loading was conducted by increasing air flow rate while keeping the inlet styrene concentration (Cin) constant in contrast to loading by increasing Cin. This switch may be due to a drastic difference in the effective surface area between these two reactors, so the biofilter becomes the reactor of choice when the rate-limiting step switches from biochemical processes to mass transfer by changing the loading mode. The presence of acetone in the mixture decreased the efficiency of styrene degradation and its degradation rate at high loadings. When the overloading was lifted by lowering the pollutant inlet concentrations, short-term back-stripping of both substrates in both reactors into the outlet air was observed, with a subsequent gradual recovery taking several hours and days in the BF and TBR, respectively. Removal of excess biomass from the TBR significantly improved the reactor performance. Identification of the cultivable strains, which was performed on Day 763 of continuous operation, showed the presence of 7 G(-) bacteria, 2 G(+) bacteria and 4 fungi. Flies and larvae of Lycoriella nigripes survived half a year of the biofilter operation by feeding on the biofilm resulting in the maintenance of a nearly constant pressure drop.
- Klíčová slova
- Lycoriella nigripes, Trickle-bed bioreactor, acetone, backwashing, biofilter, biofiltration, styrene,
- MeSH
- aceton chemie MeSH
- bioreaktory * MeSH
- filtrace metody MeSH
- látky znečišťující vzduch chemie MeSH
- lidé MeSH
- styren chemie MeSH
- znečištění ovzduší prevence a kontrola MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- aceton MeSH
- látky znečišťující vzduch MeSH
- styren MeSH
Performance of a two-stage biofiltration system was investigated for removal of styrene-acetone mixtures. High steady-state acetone loadings (above C(in)(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 C(in)(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.
- Klíčová slova
- Acetone, biofilm identification, biofiltration, intermediates, styrene, two-stage reactor,
- MeSH
- aceton chemie MeSH
- Bacteria metabolismus MeSH
- biodegradace MeSH
- biofilmy * MeSH
- bioreaktory * MeSH
- filtrace metody MeSH
- plyny chemie MeSH
- styren chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- aceton MeSH
- plyny MeSH
- styren MeSH
A granular-activated-carbon-packed biofilter receiving a constant loading rate of styrene was subjected to changes in residence time and concentration, and the effects on performance characteristics and the composition of biofilm along the bed height in the biofilter were studied. This study was carried out during the last 3 months of the entire biofilter operation of 16 months. The total bed height of the biofilter was physically divided into four individual reactor stages in series. This configuration permitted measurement of the leachate pH in each stage. Also, between-stage mixing of the culture was minimized. Each reactor stage was loaded in an upflow mode. The shortest residence time tested, 1.05 min, resulted in a decrease of removal efficiency to 95% (from 100% achieved at longer residence times). The shorter residence time nonetheless resulted in a higher elimination capacity in the higher stages of the filter bed. In the first two stages, the leachate pH values were 6.4 and 6.6, slightly lower than in higher stages (pH 7). A decrease of the styrene concentration along the bed height significantly affected the total cell number of immobilized cells whereas the number of degraders, Pseudomonads, and eukaryotes changed only a little. Microbial analysis of the mixed culture showed the presence of four bacterial strains and three fungi.
- MeSH
- Bacteria klasifikace metabolismus MeSH
- biodegradace MeSH
- biofilmy MeSH
- časové faktory MeSH
- dřevěné a živočišné uhlí chemie MeSH
- filtrace MeSH
- houby klasifikace metabolismus MeSH
- koncentrace vodíkových iontů MeSH
- styren analýza chemie metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- dřevěné a živočišné uhlí MeSH
- styren MeSH
Laboratory-scale biofilters packed with a mixture of peat, bark and wood were used for xylene and toluene removal from waste air. Two kinds of peat, which differed in the resulting pH of the leachate, were chosen for degradation of the pollutants by a mixed culture. Using peat with the lower pH value, the feasibility of single and multiple pollutant loading during the start-up period and augmentation with Pseudomonas putida strains were characterized. The lower pH value of the bed resulted in higher efficiency of toluene degradation from the mixture of pollutants. At higher pH values better degradation of both pollutants was achieved. Regarding the manner of loading during the start-up period, the best results were obtained using toluene as a single pollutant in the initial phase of operation. Pseudomonas strains demonstrated a high ability to degrade both pollutants; more efficient degradation for xylene than for toluene was observed at high loading rates.
- MeSH
- biodegradace MeSH
- koncentrace vodíkových iontů MeSH
- látky znečišťující vzduch metabolismus MeSH
- Pseudomonas putida metabolismus MeSH
- půda MeSH
- toluen metabolismus MeSH
- xyleny metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- látky znečišťující vzduch MeSH
- půda MeSH
- toluen MeSH
- xyleny MeSH
Efficient removal of nitrate under low temperature is challenging because of the reduction of the microbial activity. This study successfully explored the promotion on the performance of denitrification utilizing the immobilized biochar in biofilters under low temperature (6 ± 2 °C). The results showed that the immobilized biochar increased the denitrification rate by 76.8% and decreased the nitrous oxide emissions by 82.5%. Mechanistic studies revealed that the immobilized biochar increased the activities of the denitrifying enzymes and three enzymes involved in glycolysis. Furthermore, the immobilized biochar elevated the activity of the electron transport system by 31.8%. Finally, structural equation model explained that the increase of nitrate reductase activity was a crucial factor to enhance the total nitrogen removal efficiency in biofilters with immobilized biochar. Overall, the use of immobilized biochar can be a novel strategy to enhance nitrogen removal and reduce greenhouse gas emissions in biofilters under low temperature.
- Klíčová slova
- Biofilter, Denitrification, Enzyme activity, Immobilized biochar, Low temperature, Microbial community,
- MeSH
- denitrifikace * MeSH
- dřevěné a živočišné uhlí * MeSH
- dusík MeSH
- oxid dusný MeSH
- teplota MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- biochar MeSH Prohlížeč
- dřevěné a živočišné uhlí * MeSH
- dusík MeSH
- oxid dusný MeSH
The aim of this study was to evaluate the treatment of organic-carbon-deficient wastewater containing benzotriazole (BTA) in lab-scale aerated biofilters filled with natural manganese oxide ore, sand coated with synthetic manganese oxides and sand (as a control material) in terms of BTA removal efficiency, its transformation products and ecotoxicological impact of the treated wastewater. Additionally, the effect of Mn(II) feeding was tested. The removal of BTA in all the biofilters was ≥97%. The contribution of the biotic removal of this compound was 15%, 50%, and 75% in the systems filled with sand, synthetic and natural manganese oxides, respectively. Only the columns filled with natural manganese oxides provided significant removal of DOC and decrease of UV254 and SUVA254, with even more pronounced effect with Mn(II) feeding. The presence of Mn(II) was also found to enhance the removal of NNH4 in the systems filled with either form of manganese oxides, otherwise the removal of NNH4 was negligible or negative. The transformation reactions of BTA were methylation, hydroxylation, and triazole ring cleavage. Based on the number of compounds and their relative abundance, the methylated transformation products were predominant in the effluent. The reduction of the ecotoxicity (Microtox bioassay) of the effluents was positively correlated with the decrease of UV254, SUVA and DOC and only moderately with the removal of BTA. This study has shown that the natural manganese oxide ore provides the broadest set of services as a filtering material for aerated biofilters treating carbon-deficient wastewater containing BTA.
- Klíčová slova
- Benzotriazole, Biofilter, Ecotoxicity, Manganese oxides, Mn(II) feeding, Transformation products,
- MeSH
- čištění vody metody MeSH
- mangan chemie MeSH
- odpadní voda chemie MeSH
- oxidy MeSH
- sloučeniny manganu MeSH
- triazoly izolace a purifikace MeSH
- uhlík MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- benzotriazole MeSH Prohlížeč
- mangan MeSH
- manganese oxide MeSH Prohlížeč
- odpadní voda MeSH
- oxidy MeSH
- sloučeniny manganu MeSH
- triazoly MeSH
- uhlík MeSH
The dataset represents micro computed tomography (µCT) images of undisturbed samples of constructed Technosol, obtained by sampling from the top layer of the biofilter in two bioretention cells. A bioretention cell is a stormwater management system designed to collect and temporarily retain stormwater runoff and treat it by filtering it through a soil media called a biofilter. Soil samples were collected at 7, 12, 18, 23, and 31 months after the establishment of bioretention cells. The constructed Technosol was composed of 50% sand, 30% compost, and 20% topsoil. The bioretention cell 1 (BC1) was designed to collect water from the nearby building roof, and bioretention cell 2 (BC2) was without regular inflow for possible irrigation events. This allowed for the capture of the dynamics of early soil structure development. The dataset comprises a total of 120 three-dimensional µCT images. The 16-bit µCT images obtained by industrial scanner have resolutions of 12 and 20 µm. The characteristics of total porosity, volumetric weight of the dry sample and field capacity were determined in the laboratory for each sample. The generated dataset captures the soil structure development within the biofilter during the initial years of operation of bioretention cells with two distinct water regimes. Originally produced to describe the development of the macropore system during early biofilter evolution, this extensive and high-quality dataset can be reused for further studies on constructed Technosol evolution, focusing on soil structure or hydraulic properties. It is particularly beneficial for research into macropore network development and changes in hydraulic properties in constructed soils. The dataset can support model validation and improve understanding of soil property variability in bioretention systems. It serves as a valuable resource for researchers who lack the means to collect and scan their own samples.
- Klíčová slova
- Biofilter, Bioretention cell, Constructed Technosols, Rain garden, Soil structure, Swale, Urban soil, X-ray microtomography,
- Publikační typ
- časopisecké články MeSH
Two cost-effective packing materials were used for n-butyl acetate removal in lab-scale biofilters, namely waste spruce root wood chips and biochar obtained as a byproduct from a wood gasifier. Three biofilters packed with spruce root wood chips: without biochar (SRWC), a similar one with 10% of biochar (SRWC-B) and that with 10% of biochar impregnated with a nitrogen fertilizer (SRWC-IB) showed similar yet differing maximum elimination capacities of 206 ± 27, 275 ± 21 and 294 ± 20 g m-3 h-1, respectively, enabling high pollutant removal efficiency (>95% at moderate loads) and stable performance. The original biochar adsorption capacity was high (208 ± 6 mgtoluene g-1), but near 70% of it was lost after a 300-day biofilter operation. By contrast, the exposed impregnated biochar drastically increased its adsorption capacity in 300 days (149 ± 7 vs. 17 ± 5 mgtoluene g-1). Colony forming unit (CFU) and microscopic analyses revealed significant packing material colonization by microorganisms and grazing fauna in all three biofilters with an acceptable pressure drop, up to 1020 Pa m-1, at the end of biofilter operation. Despite a higher price (14 vs. 123 €m-3), the application of the best performing SRWC-IB packing can reduce the total investment costs by 9% due to biofilter volume reduction.
- Klíčová slova
- CFM, Packing material, biochar, biofilter, grazing fauna, impregnated biochar, n-butyl acetate, root spruce wood, waste air treatment,
- MeSH
- acetáty * MeSH
- biodegradace MeSH
- dřevěné a živočišné uhlí * MeSH
- filtrace * MeSH
- toluen MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- acetáty * MeSH
- biochar MeSH Prohlížeč
- butyl acetate MeSH Prohlížeč
- dřevěné a živočišné uhlí * MeSH
- toluen MeSH
Styrene vapors from contaminated air were eliminated using long-term adapted mixed microbial culture inoculated on four perlite packed biofilters (serial arrangement, up-flow configuration). During start-up the inlet concentration of styrene rose from 175 to 1300 mg/m3 of total carbon. The total actual residence time in the four biofilters was 24 s. Styrene was successfully degraded by the microbial population in the biofilter. An average of 66% of eliminated styrene was transformed to CO2. The removal efficiency of the pollutant was, after 18 d of start-up, nearly 85% at an organic load of 170 g/m3 per h. The concentration profiles along the bed height were linear for various pollutant inlet concentrations. The total amount of microorganisms in analyzed biomass from the biofilters was about 10(9) per gram of dry packing mass. The moisture content was around 80% in all biofilters.
The knowledge gaps regarding the degradation of sulfamethoxazole (SMX) in biofilters include the effect of aeration, constant feeding with readily biodegradable organic carbon and the presence of reactive media such as manganese oxides (MnOx). Thus, the goal of this study was to assess the removal of SMX in lab-scale biofilters with various operation variables: aeration, presence of MnOx as an amendment of filtering medium and the presence of readily biodegradable organic carbon (acetate). The sand used in the experiment as a filtering medium was previously exposed to the presence of SMX and acetate, which provided acclimation of the biomass. The removal of SMX was complete (>99%) with the exception of the unaerated columns fed with the influent containing acetate, due to apparent slower rate of SMX degradation. The obtained results suggest that bacteria were able to degrade SMX as a primary substrate and the degradation of this compound was subsequent to the depletion of acetate. The LC-MS/MS analysis of the effluents indicated several biotransformation reactions for SMX: (di)hydroxylation, acetylation, nitrosation, deamonification, S-N bond cleavage and isoxazole-ring cleavage. The relative abundance of transformation products was decreased in the presence of MnOx or acetate. Based on the Microtox assay, only the effluents from the unaerated columns filled with MnOx were classified as non-toxic. The results offer important implications for the design of biofilters for the elimination of SMX, namely that biofilters offer the greatest performance when fed with secondary wastewater and operated as non-aerated systems with a filtering medium containing MnOx.
- Klíčová slova
- Aeration, Biofilters, Ecotoxicity, Manganese oxides, Sulfamethoxazole, Transformation products,
- MeSH
- aklimatizace MeSH
- chemické látky znečišťující vodu * MeSH
- chromatografie kapalinová MeSH
- sulfamethoxazol * MeSH
- tandemová hmotnostní spektrometrie MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- chemické látky znečišťující vodu * MeSH
- sulfamethoxazol * MeSH
