Josiane Nikiema

Treatment of VOCs in biofilters inoculated with fungi and microbial consortium.

An experimental study on the removal of xylene vapours from an air stream was conducted on three identical upflow laboratory‐scale wood‐chips‐based bed biofilters. Three different inoculums were used: fungi (Phanerochaete chrysosporium and Cladosporium sphaerospermum), a bacterial consortium (EVB110), and a mixed culture of fungi and EVB110. The empty bed gas residence time was 59 s, and various inlet concentrations of the contaminant were tested. The results obtained revealed a strong correlation between the average temperature of the biofilter and the intensity of the microbial activity in the filter bed. In addition, the mass of carbon dioxide produced per mass of xylene removed was equal to 3.03, indicating elimination of the pollutant by aerobic biodegradation. The removal rates of xylene in both fungal and bacterial systems were similar up to an inlet load of 100 g m−3 h−1. However, a better performance was achieved in the fungal system at higher inlet loads of the pollutant. The maximum elimination capacity achieved in the fungal and bacterial systems was 77 and 58 g m−3 h−1, respectively; and an early set‐off of the inhibition effects was observed in the latter. The bioreactor inoculated with the mixed culture was the least effective, with a maximum elimination capacity of only 38 g m−3 h−1. Problems with microbial population survival and competition among different types of microorganisms could be responsible of this lower performance. The fungal system was also tested for the removal of toluene vapour and achieved a maximum elimination capacity of 110 g m−3 h−1.

Production of Biodiesel from Microalgae

Since the early 70s, several major energy crises have forced the scientific community to find alternative sources of power. In July 2008, the price of crude petroleum reached 145

ANALYSIS OF THE EFFECTS OF TEMPERATURE, THE AMOUNT OF NUTRIENT SOLUTION AND THE CARBON DIOXIDE CONCENTRATION ON METHANE BIOFILTRATION

US/barrel, the highest price ever achieved in 30 years (BP, 2011; Ervin & Associated, 2011). In July 2011, the price of crude petroleum was still relatively high at 108

Biofiltration Of Methane: Effect Of TemperatureAnd Nutrient Solution

US/barrel (Ervin & Associated, 2011). Moreover, the 2008 world economic crisis encouraged the United States government to develop biofuels in order to blend them with petroleum fuels without engine modifications or distribution process changes (Bindraban et al., 2009; The White House, 2010). Furthermore, in Canada, by 2012, the objective of adding biodiesel into transportation diesel and heating fuels is 2% (v/v) (Natural Ressources Canada, 2011b).

Elimination of methane generated from landfills by biofiltration: a review

Landfi ll gas emissions contribute to the greenhouse effect due to the presence of methane (CH 4 ). CH 4 emissions from old and small landfi lls can be reduced by using biofi ltration. The objective of this study was to optimize parameters that control CH 4 removal in a biofi lter. Temperature is one of the important parameters as well as the amount of nutrient solution (NS) supplied. The effects of the carbon dioxide (CO 2 ) concentration on CH 4 biofi ltration were also studied. Four biofi lters using an inorganic fi lter bed were studied under similar conditions: an inlet CH 4 concentration of 7000 ppmv and an air fl ow rate of 0.25 m 3 /h. A NS was supplied daily. The temperature was varied from 4°C to 43°C. The highest performance was obtained in the range of 31–34°C with an elimination capacity (EC) of 30 g CH 4 /m 3 /h for an inlet load (IL) of 80 g CH 4 /m 3 /h. The effect of the amount of NS supplied to the biofi lter at ambient temperature was also analyzed. The EC was 23 g CH 4 /m 3 /h for both 101 L NS /m 3 V bed /d and 34 L NS /m 3 V bed /d, but it fell to 17 g CH 4 /m 3 /h at 17 L NS /m 3 V bed /d. CO 2 concentrations were varied from 650 to 18,500 ppmv and no effect was noticed on the EC which remained constant at 18 g CH 4 /m 3 /h for an inlet load of 72 g CH 4 /m 3 /h.

Biofiltration of methane: An experimental study

Methane is a greenhouse gas (GHG) 21 times more contributing to global warming than carbon dioxide (CO2) and originates mainly from the energy, agriculture and landfill sectors. Methane can be valorized via combustion or transformed by catalytic processes into products like methanol. When valorization cannot be applied because of inappropriate flow rates or methane concentrations, biofiltration is a biotechnology well adapted to control the methane emissions. Biofiltration is a triphasic biotechnology, which uses microorganisms to reduce pollutants like volatile organic compounds (VOCs) or volatile inorganic compounds (VICs) or GHG like methane. Several studies have been published over the last three decades about VOC and VIC biofiltration, but fewer studies are available about methane control. At the Universite de Sherbrooke, research is being conducted to control methane emissions originating from landfills or livestock productions. The biofilter used in this study is a laboratory-scale bioreactor of 0.018 m divided into 3 sections. An inorganic packing material is used as the filter bed and a nutrient solution is supplied to irrigate the biofilter once daily. The objective of the present study is to determine the operating conditions to obtain high removal efficiencies at methane inlet concentrations around 7000 ppmv. The biofilter is operated under a nitrogen concentration of 0.5 gN/L and an inlet flow rate of air/methane mixture of 0.25 m/h. The parameters tested are the temperature of the bed filter and the amount of nutrient solution supplied to the biofilter. Better performances are obtained in the temperature range of 28-30°C with an elimination capacity of 39 gCH4/m/h for an inlet load of 67 gCH4/m/h. Reducing the daily amount of nutrient solution from 1500 to www.witpress.com, ISSN 1743-3541 (on-line)