Steady-state and transient-state performance of a biotrickling filter treating chlorobenzene-containing waste gas

Abstract

Biotrickling filter (BTF) technology was applied for the treatment of waste gas containing a mixture of chlorobenzene and 1,2-dichlorobenzene. An adapted microbial community was immobilised on a structured packing material. The strategy followed was to reach high removal efficiencies at initially low mass loading rates followed by an increase of the latter. This procedure was successful and resulted in a short start-up period of only 2 weeks. A 3-month operation under steady-state conditions showed good performance, with >95% removal efficiency at a mass loading rate of 1,800 g m(-3) day(-1). Dimensionless concentration profiles showed that the chlorobenzenes were simultaneously degraded. Low dissolved organic carbon of 15 mg l(-1) and stoichiometric chloride concentrations in the trickling liquid indicated complete mineralisation of the pollutant. Transient-state experiments with five times higher mass loading rates caused a decrease in the removal efficiency that recovered rapidly once the mass loading rate returned to its original steady-state level. A progressive increase of the mass loading rate in a long-term performance experiment showed that the removal efficiency could be kept stable between 95 and 99% at loads of up to 5,200 g m(-3) day(-1) over several days. Above this mass loading rate, the elimination capacity did not increase any further. These results demonstrated that with a well-adapted inoculum and optimal operation parameters, a BTF system with excellent performance and stability that efficiently removes a mixture of chlorobenzene vapours from air can be obtained.

Comparative study of the elimination of toluene vapours in twin biotrickling filters using two microorganisms Bacillus cereus S1 and S2

“…A thinner liquid film can shorten the diffusion distance of toluene, and capture by bacteria of toluene molecules is easier and more rapid with a thin film. The capability of the biotrickling filter to purify toluene in the waste gas is thus intensified, and vice versa, 8 because most of the degradation occurs in the biofilm, although in selected cases, significant activity can occur in the recycle liquid. 21 For strain S1, the degradation capacity is much higher than that of strain S2.…”

Microbial degradation of chlorinated benzenes

“…In another study, the removal of CBs during infiltration of water into sand dunes as part of a drinking water treatment scheme was evaluated with laboratory-scale columns (V = 0.6 or 5.7 l) filled with sand (Bosma et al 1996). Under aerobic conditions, CB, 1,2-DCB, 1,3-DCB, 1,4-DCB, and 1,2,4-TCB were removed by [99, 90, 30, 90, and 40%, respectively. Several studies considered the removal of CB in waste gases in biological trickling reactors (Oh and Bartha 1994;Mpanias and Baltzis 1998;Seignez et al 2004;Mathur et al 2006). In the first study, a laboratory biotrickle column of 1.57 l was packed with perlite and used to treat CB and 1,2-DCB vapors supplied at concentrations of 1.2 and 0.7 g m -3 air, respectively (Oh and Bartha 1994).…”

“…Maximum volumetric removal rates of up to 1,500 g m -3 reactor day -1 were obtained. In the third study, a 40-l biotrickle reactor with cylindrical PVC as packing (Seignez et al 2004) was used to treat mixtures of CB and 1,2-DCB. After 3 months of operation at steady-state, the reactor achieved maximum volumetric loading rates of 5,200 g m -3 reactor day -1 with removal efficiencies in the range of 95-99%.…”

Transient performance of two‐phase partitioning bioreactors treating a toluene contaminated gas stream

“…Longer step changes were studied by Seignez et al (2004) who induced 2-3-h step changes in a biotrickling filter treating chlorobenzene-containing waste gas. When the inlet feed stream was increased from 75 to 375 g/m 3 /h (five times the nominal loading rate) the instantaneous removal efficiency of the system dropped from values above 95% to a minimum of 55% and took almost 6 h to fully recover.…”