Effects of packing material on the biofiltration of benzene, toluene and xylene vapours

Abstract

Biofiltration was used to eliminate volatile organic compounds from air streams in bench-scale reactors inoculated with an adapted consortium. Organic and inert supports were tested on 100 days of operation. The supports were: peat, vermiculite, a mixture of vermiculite and activated carbon, tree bark and, porous glass Rashig rings. A mixture of benzene, toluene and xylene vapors with a load of 200 gC m(-3) h(-1) was fed to the biofilters with an empty bed residence time of 60 s. Removal efficiencies higher than 95% were obtained with the mixture of vermiculite and activated carbon, 85% for peat and bark, 80% for vermiculite and 65% for the Rashig rings. In all cases, drying problems in beds were observed after several days of operation. Water addition with or without nutrients was required to maintain and increase the performance of biofilters. In steady state operation, experiments at loads ranging from 50 to 400 gC m(-3) h(-1) were carried out and a maximum elimination capacity of 260 gC m(-3) h(-1) was obtained for vermiculite-activated carbon support. The three xylene isomers were degraded. Observations of the supports surface by scanning electronic microscopy at the end of the biofiltration experiment showed abundant growth of fungi, which were not in the inoculum, had colonized the biofilter.

Interaction between sorption and biodegradation in a biofilter packed with activated carbon

“…If elimination capacities remain constant, the increase in carbon dioxide concentration can be only attributed to the microorganisms, which are also able to oxidize the organic matter previously adsorbed on the surface of the material. In this sense, Ortiz et al (2003) affirmed that sorption can favor the contact between microorganisms and the pollutants.…”

“…Abumaizar et al (1998) showed that biofilters containing granular activated carbon exhibited significantly higher removal efficiencies and more stable operation during sudden load increases than biofilters containing only compost. Ortiz et al (2003) studied the effect of the presence of activated carbon in a vermiculite-based biofilter observing positive effects in the removal efficiencies. Dorado et al (2009) demonstrated that a sludge-based carbon with a high capacity to smooth inlet load changes was a good support to immobilize and grow the biomass obtaining relative good removal efficiencies (up to 90%).…”

“…Among their main disadvantages, organic materials tend to be eventually biodegraded bringing a loss of structure as well as require of frequent replacement. Inorganic materials have uniform structure and size which reduce compaction and allow better air distribution, resistance to water addition and can be cleaned and regenerated (Ortiz et al 2003).…”

Start-up and performance characteristics of a trickle bed reactor degrading toluene

“…In the following 32 days of operation, the system was loaded by the air flow rate with a constant toluene inlet concentration of 100 mg.m -3 (Fig. 3) (Morales et al, 1998), compost (Delhomenie et al, 2003, vermiculite (Ortiz et al, 2003), perlite (Arriaga and Revah, 2005), activated carbon (Li et al, 2002 . Therefore, an EBRT of 35s was the optimal value for this system, with respect to sufficient air cleaning at a good elimination capacity of 7.5 g C .m…”

Optimization of Nitrification Process by a Bacterial Consortium in the Submerged Biofiltration System with Ceramic Bead Carrier

“…Although the cost of inert filter beads, in most cases, is higher compared to that of organic counterparts, the former have a range of advantages: chemical and physical inactivity, long lifetime, high performance, more regular shape, uniform air distribution, and reduced number of channeling issues. In addition, inert carriers are also much easier to clean and replace [1,9,14]. Porous ceramic beads have also been shown to be an appropriate packing material for biofilters due to their high gas and liquid film mass transfer coefficients [12].…”