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Biofilter Performance (biofilter + performance)
Selected AbstractsMathematical modeling of gas-phase biofilter performanceJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2003Hasnaa Jorio Abstract In the present paper, a new mathematical model describing the physical, chemical and biological phenomena involved in the process of contaminant removal in biofilters is developed. In addition to the contaminant, the key components of the present theoretical model are carbon dioxide and oxygen. The model predicts the concentration profile of the key components in the gas phase, the biofilm and the sorption liquid retained in the solid particles composing the filter bed at both steady and transient regimes. The model equations were solved numerically and comparison between theory and experiment showed that the model results for styrene and carbon dioxide concentration profiles were in very good agreement with experimental data for the biofiltration of styrene vapors at steady state. The analysis of oxygen concentration profile in the biofilm predicted by the theoretical model revealed that oxygen limitation does not occur under the operating styrene biodegradation rate in the biofilter. Copyright © 2003 Society of Chemical Industry [source] Influence of nitrogen on the degradation of toluene in a compost-based biofilterJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 9 2001Marie-Caroline Delhoménie Abstract Two identical laboratory-scale bioreactors were operated simultaneously, each treating an input air flow rate of 1,m3,h,1. The biofilters consisted of multi-stage columns, each stage packed with a compost-based filtering material, which was not previously inoculated. The toluene inlet concentration was fixed at 1.5,g,m,3 of air. Apart from the necessary carbon, the elements nitrogen, phosphorus, sulfur, potassium and other micro-elements are also essential for microbial metabolism. These were distributed throughout the filter bed material by periodic ,irrigations' with various test nutrient solutions. The performance of each biofilter was quantified by determining its toluene removal efficiency, and elimination capacity. Nutrient solution nitrogen levels were varied from 0 to 6.0,g,dm,3, which led to elimination capacities of up to 50,g,m,3,h,1 being obtained for a toluene inlet load of 80,g,m,3,h,1. A theoretical analysis also confirmed that the optimum nitrogen solution concentration lays in the range 4.0,6.0,g,dm,3. Validation of the irrigation mode was achieved by watering each biofilter stage individually. Vertical stage-by-stage stratification of the biofilter performance was not detected, ie each filter bed section removed the same amount of pollutant, the elimination capacity per stage being about 16,g,m,3,h,1 per section of column. © 2001 Society of Chemical Industry [source] Modeling and design of vapor-phase biofiltration for chlorinated volatile organic compoundsAICHE JOURNAL, Issue 9 2002Walter Den A mathematical model was developed for biofilter design and performance prediction with reference to the purification of contaminated gas streams. The model incorporated important aspects such as mass transfer, biodegradation, and adsorption processes. A systematic modeling protocol incorporated the development of a scale-up strategy based on dimensional analysis and similitude. Trichloroethylene (TCE) was employed as the model contaminant for biofiltration testing and model verification. The biokinetic and adsorption parameters for the contaminant were determined independently from a series of minibiofilter and miniadsorber column experiments, specifically designed to simulate the actual biofilter operational regimes in a miniature scale. Bench-scale biofilter experiments employing granular activated carbon columns indicated the good predictive capability of the model for the removal of TCE. Dynamic simulation studies were performed to assess the transient- and steady-state behavior of the model under various operating conditions. Model sensitivity was studied to evaluate the influence of adsorption equilibrium, transport and biological parameters on the biofilter dynamics. The results demonstrated that the biofilter performance was greatly influenced by the Monod coefficients and the biofilm thickness. [source] Removal of TEX vapours from air in a peat biofilter: influence of inlet concentration and inlet loadJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2006Carmen Gabaldón Abstract This paper presents the results of the study of the removal of toluene, ethylbenzene, and o -xylene (TEX) by biofiltration using a commercial peat as filter-bed material. Runs with a single organic compound in air, and with the mixture of TEX in air, were carried out for at least 55 days in laboratory-scale reactors inoculated with a conditioned culture. The influence of organic compound inlet load and of gas flow rate on the biofilter's performance was studied, including relatively high values of pollutant inlet concentration (up to 4.3 gC m,3 for ethylbenzene, 3.2 gC m,3 for toluene, and 2.7 gC m,3 for o -xylene). Results obtained show maximum elimination capacities of 65 gC m,3 h,1 for o-xylene, 90 gC m,3 h,1 for toluene, and 100 gC m,3 h,1 for ethylbenzene, and high removal efficiency (>90%) even for moderately elevated concentrations: 3.0, 2.5 and 1.8 gC m,3 for ethylbenzene, toluene and o -xylene, respectively. The behaviour of the TEX mixture was in good agreement with the results obtained for the runs in which only one organic compound was present. Ethylbenzene and toluene are degraded easier than o -xylene, and inhibitory effects due to the presence of multiple substrates were not observed. Copyright © 2005 Society of Chemical Industry [source] Development and simulation studies of an unsteady state biofilter model for the treatment of cyclic air emissions of an ,-pinene gas streamJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2005Christina Dirk-Faitakis Abstract This paper describes the development and simulation of an unsteady state biofilter model used to predict dynamic behaviour of cyclically-operated biofilters and compares it with experimental results obtained from three, parallel, bench-scale biofilters treating both periodically fluctuating concentrations and constant concentrations of an ,-pinene-laden gas stream. The dynamic model, using kinetic parameters estimated from the constant concentration biofilter, was able to predict the performance of cyclic biofilters operating at short cycle periods (ie, in the order of minutes and hours). Steady state kinetic data from a constant concentration biofilter can be used to predict unsteady state biofilter operation. At a 24 h cycle period, the dynamic model compared well with experimental results. For long cycle periods (ie, hours and days), removal efficiency decreased after periods of non-loading: the longer the period of non-loading, the poorer the biofilter's performance at the re-commencement of pollutant loading. At longer time scales the model did not effectively predict transient behaviour, as adsorption and changes in kinetic parameters were not accounted for. Modelling results showed that similar biofiltration performance for the cyclic and constant concentration biofiltration of ,-pinene is expected for biofilters operating solely in the first order kinetics regime. Poorer performance for cyclic biofilters following Monod kinetics spanning the entire kinetics range is expected as the cycle amplitude increases. The most important parameters affecting the performance of a cyclically-operated biofilter with short cycle periods are: amplitude of cyclic fluctuations, Cg, max/Cg, relative value of the half-saturation constant in the Monod expression, Ks, and effective diffusivity of ,-pinene in the biofilm, De. Copyright © 2005 Society of Chemical Industry [source] | ||||||||||