Modeling of a vapor-phase fungi bioreactor for the abatement of hexane: Fluid dynamics and kinetic aspects

Abstract

During some previous works, a packed-bed lab-scale biofilter (177 . 10(-6) m3), inoculated with a selected strain of Aspergillus niger had been tested for the abatement of hexane vapors, showing a maximum elimination capacity of 200 g hexane/m3 reactor/h. A steady-state mathematical model taking into account axial dispersion effect was applied to describe the process and predict experimental results, but many model parameters could not be calculated from experimental data. The aim of the present work was to carry out further investigations to accurately determine the dispersion coefficient and the kinetics parameters to verify the effective validity of the model. Analysis of residential time distribution revealed the presence of a certain degree of axial dispersion (dispersion coefficient D of 1.22 . 10(-4) m2/s). Experimental data from kinetic trials carried out in reduced height reactors, together with data from full-scale runs, were elaborated to estimate the kinetic saturation constant (K(s)), the coefficient yield (Y), the maximum growth rate (mu(max)) and maximum substrate degradation rate (r(max)). All these parameters were introduced into the model, which was then solved by simulation software finding a good correlation between experimental and theoretical results.

Phase partition of gaseous hexane and surface hydrophobicity of Fusarium solani when grown in liquid and solid media with hexanol and hexane

“…The HPC of F. solani grown in biofilters has a 200-fold increase in n-hexane bioavailability as compared to water. Although these values were obtained in vitro they may partially explain why fungal biofilters have shown high performance with hydrophobic substrates, (van Groenestijn and Liu 2002;Arriaga and Revah 2005a, b;Spigno and De Faveri 2005).…”

“…The use of Fusarium solani by Arriaga and Revah (2005a) in a Perlite-packed biofilter attained EC values from 50 g m -3 h -1 to 130 g m -3 h -1 with an inlet n-hexane concentration from 1 g m -3 to 11 g m -3 . Spigno and De Faveri (2005) found an EC of n-hexane of 150 g m -3 h -1 using Aspergillus niger.…”

“…Furthermore, bacterial biofilms offer a low surface area for the transfer of these contaminants from the gas to the biologically active phase (van Groenestijn and Kraakman 2005). One alternative to improve these limitations is to use filamentous fungi as the biological agents (van Groenestijn and Liu 2002;Arriaga and Revah 2005a, b;Spigno and De Faveri 2005).…”

“…Recent work by Arriaga and Revah (2005a, b) and Spigno and De Faveri (2005) showed a greater elimination capacity (EC) of n-hexane in biofilters with filamentous fungi. The use of Fusarium solani by Arriaga and Revah (2005a) in a Perlite-packed biofilter attained EC values from 50 g m -3 h -1 to 130 g m -3 h -1 with an inlet n-hexane concentration from 1 g m -3 to 11 g m -3 .…”

Treatment of hydrophobic VOCs in trickling bed air biofilter: Emphasis on long-term effect of initial alternate use of hydrophilic VOCs and microbial species evolution

“…Many processes were tested for addressing the bioavailability of hydrophobic contaminants. One is the introduction of surfactants (Aly Hassan and Sorial, 2008;Woertz and Kinney, 2004), providing favorable conditions for fungi (Aly Hassan and Sorial, 2008;Arriaga and Revah, 2005a;Hernández-Meléndez et al, 2008;Spigno and De Faveri, 2005;Van Groenestijn et al, 2001); others include mixture of n-hexane with other less hydrophobic compound such as benzene (Aly Hassan and Sorial, 2010a), introduction of more hydrophilic contaminants in mixture with n-hexane, such methanol (Zehraoui et al, 2012(Zehraoui et al, , 2013, and most recently the alternate use of methanol with n-hexane (Zehraoui et al, 2014).…”