Biomass accumulation in a biofilter treating toluene at high loads – Part 1: Experimental performance from inoculation to clogging

Abstract

Biomass accumulation was studied in a biofilter packed with an organic/inorganic, hybrid packing material made of clay pellets plus clay pellets covered by a thin layer of compost and inoculated with activated sludge from a municipal WWTP. Operating conditions under high loads of toluene were selected to force plant failure by clogging. The biofilter achieved a remarkably maximum elimination capacity of 595 g toluene •m-3 •h-1 (1280 g toluene•m-3 •h-1 based on the first 25 cm of the biofilter). The evolution of biofilter performance and biomass growth over the packing material were studied until the reactor collapsed. Several variables related to biomass growth such as reactor weight, oxygen consumption, CO 2 production, substrate removal and pressure drop were monitored. Alternated periods of substrate supply and starvation were tested to assess biomass growth and detachment. Moreover, pH and biomass content were periodically measured in the leachate to determine the washing efficiency of intermittent watering. Pressure drop measurements demonstrated that watering was an effective technique to wash the excess of biomass accumulated. Experimental data also permitted to determine important parameters for biofilter modeling as the biomass growth yield and the stoichometric coefficients of toluene biological oxidation. Variables monitored are sensitive to biomass accumulation

Profiling of oxygen in biofilms using individually addressable disk microelectrodes on a microfabricated needle

“…A mineral medium solution (prepared according to [32]) was supplied to the reactor using glucose as carbon source. The hydraulic residence time ranged from 4 to 8 hours throughout the FPB operation.…”

Biofilm dynamics characterization using a novel DO-MEA sensor: mass transport and biokinetics

“…A peristaltic pump (MCP Standard, Ismatec, Germany) was used to feed the reactor with a nutrient solution (Dorado et al 2012) containing glucose as the sole carbon and energy source at 13 g·l -1 , and a second peristaltic pump (Miniplus 3, Gilson, France) served to recirculating the liquid phase through the reactor.…”

An Investigation on the Efficiency of Air Purification Using a Biofilter with Activated Bed of Different Origin

“…Since toluene is an organic material much less soluble in water, its concentration after this layer varied not as much as that of acetone. Removal efficiency of pollutants from cleaned air depends on gas residence time in biofilters (AlvarezHornos et al, 2007;Dorado et al 2008Dorado et al , 2010Dorado et al , 2012aGracy et al, 2006;Hwang and Tang, 1997;Jeong at al., 2006;Qi, 2005;Yoon and Park, 2002;Zilli et al, 2001). The longer is the empty bed residence time (EBRT) of polluted gas the higher removal efficiency can be observed.…”

“…Dorado et al (2012a) found that biomass accumulation in a biofilter was enhanced by the high toluene load, particle size of the material, and its spatial distribution in the bed enabled to collect information on biomass growth. The results of their experiments demonstrated that high loads of toluene can be treated by a non-specific consortium in biofiltration.…”

“…In the recent papers of Dorado et al (2008Dorado et al ( , 2010Dorado et al ( , 2012a the authors provided more information on the performance of biofilters packed with different hybrid packing material covered by a thin layer of compost and inoculated with activated sludge from a municipal WWTP and applied them to purify air containing toluene vapour. Dorado et al (2012a) found that biomass accumulation in a biofilter was enhanced by the high toluene load, particle size of the material, and its spatial distribution in the bed enabled to collect information on biomass growth.…”