Elimination of Methanol and Ethanol by Biofiltration: An Experimental Study

Abstract

This study presents the experimental results obtained during long-term operation of two biofilters treating two alcohols: methanol and ethanol. The biofilters used for this purpose were previously packed with a compost material made from tobacco processing residues. The alcohols concentrations tested lay between 0.40 and 3.20 g/m 3 for methanol, and 0.55 and 5.05 g/m 3 for ethanol. The empty bed residence time in each biofilter was 60 s. Biofilter inlet loads of less than 190 and 300 g/m 3 /h for the methanol and ethanol additions respectively, were thereafter evaluated. In addition, the concentrations of nutrient nitrogen were also varied, from 0.1 to 2.0 g-N/l and from 0.3 to 11.3 g-N/l for the ethanol and the methanol, respectively. The results thus obtained have made it possible to select the optimal nitrogen concentrations which, for the cases examined, turn out to be 0.3 g-N/l and between 2 and 3.8 g-N/l for the ethanol and methanol substrates, respectively. The maximum elimination capacities obtained in this study were 82 and 150 g/m 3 /h, respectively for the methanol and ethanol cases. It was therefore concluded that, for a readily biodegradable compound such as ethanol, the nitrogen requirement is substantially lower than that needed for the methanol degradation, the latter appearing to be more difficult to degrade biologically under similar operating conditions. The production rate of the co-product carbon dioxide during methanol and ethanol biofiltration was also investigated. Also, a good correlation was found to exist between the temperature and the conversion achieved in the biofilter.

Biofiltration of high concentrations of methanol vapors: removal performance, carbon balance and microbial and fly populations

“…Mainly, system IL was rather high, surpassing biodegradation rates. This is reinforced by the fact that methanol ECs are usually below 200 g m −3 h −1 . Moreover, higher methanol availability could have induced excessive biomass growth with associated clogging and pressure drop increase, preventing homogeneous air distribution in the filter bed and hindering performance .…”

“…Methanol mineralization (%) was estimated by dividing P CO2 by the theoretical stoichiometric CO 2 production, assuming a complete oxidation of methanol and neglecting biomass formation (1.38 g of CO 2 produced per gram of methanol) …”

Steady state and dynamic behaviors of a methane biofilter under periodic addition of ethanol vapors

“…Unlike CH 4 , there is no limitation for ethanol solubility in the biofilm phase since ethanol is miscible with water (Mackay et al, 2006). Ethanol was removed completely (RE of 100%) in biofilters for ILs up to 100 g ethanol m À3 h À1 under EBRTs shorter than 1 min (Christen et al, 2002;Dastous et al, 2008). Fig.…”

“…The CH 4 leakage from anaerobic wastewater treatment plants of food industries can include ethanol (United States Environmental Protection Agency, 2016). Ethanol is also considered a hazardous component for humans and targeted for removal in biofilters (Christen et al, 2002;Dastous et al, 2008). Unlike CH 4 which has poor solubility (dimensionless Henry's law constant of 28 at 25 C, P ¼ 1 atm) (Staudinger and Roberts, 1996), ethanol is completely miscible with water with a low dimensionless Henry's constant (0.002 at 25 C, P ¼ 1 atm).…”

“…Therefore, ethanol is more readily bioavailable in the biofilm phase compared to CH 4 under similar conditions in the biofilters (Mackay et al, 2006). Ethanol biofilters are usually subjected to EBRTs shorter than 1 min (Dastous et al, 2008). In contrast, EBRTs longer than 4 min for CH 4 biofilters can provide sufficient contact time between CH 4 and the biofilm phase and can increase the bioavailability of CH 4 in biofilm (Hern andez et al, 2015;Lebrero et al, 2016).…”