Biological treatment of a contaminated gaseous emission from a paint and varnish plant—from laboratory studies to pilot‐scale operation

Abstract

A Vapour-Phase Bioreactor (VPB), namely a biotrickling filter, was scaled-up and operated insitu for the treatment of gaseous emissions from a paint and varnish industrial plant. A microbial culture able to degrade the target compounds was enriched and a laboratory-scale VPB was established in order to evaluate the treatment's performance. The VPB presented removal efficiencies higher than 90% when exposed to Organic Loads (OL) of ca 50 g h −1 m −3 of reactor. The VPB was exposed to dynamic conditions often found in-situ (eg night and weekend shutdown periods) and showed a fast capacity to recover, with and without mineral medium recirculation. After a prolonged interruption period (10 months), the VPB was not able to cope with OL of ca 25 g h −1 m −3 of reactor and re-inoculation was required in order to recover the treatment performance. The VPB also showed limited treatment when exposed to higher OL (ca 500 g h −1 m −3 of reactor). The VPB was then scaled-up and a 3 m 3 VPB was operated in-situ, showing removal efficiencies higher than 50% when exposed to an OL of c 5 g h −1 m −3 of reactor, thus complying with current legal demands. The addition of a maintenance feed was shown to be a useful tool for VPB pilot-scale operation when shutdown periods occurred. A factorial design of experiments was carried out, which allowed reduction to one-tenth of the initial supply of the main mineral medium constituents, namely phosphate buffer, ammonium and magnesium salts, and also elimination of the metal supplement. Overall, the VPBs were shown to be robust equipment, being able to respond actively to dynamic treatment scenarios, particularly night and weekend shutdown periods.

Biofiltration of paint solvent mixtures in two reactor types: overloading by hydrophobic components

“…A similar impact of hydrocarbons was reported by Bastos et al [4] after 16 days of loading, and by Moe and Qi [8] after an even shorter period of loading. An inhibitory effect was also observed in our previous study [25] while using a similar solvent mixture (only without acetone).…”

“…Their removal from waste air, e.g., from paint booths, has been attempted using both biotrickling reactors [1][2][3][4][5][6] and biofilters [7][8][9][10][11]. The greatest challenge of paint solvent biofiltration involves the removal of complex mixtures of pollutants, i.e., a multi-parameter system with inherently complex interactions.…”

Effect of loading types on performance characteristics of a trickle-bed bioreactor and biofilter during styrene/acetone vapor biofiltration

“…This detrimental effect is less characteristic for TBRs; perhaps, due to a dilution of toxic substrates in the ample aqueous medium. A similar significant non-zero RE of a TBR, even at severely overloading concentrations, was observed by Bastos et al [23] Thus, whenever frequent overloading by these two substrates is possible, the use of a TBR may be advised. If the process is conducted under steady state conditions, the bioreactor selection becomes dependent on the substrate composition.…”

Biofiltration of a styrene/acetone vapor mixture in two reactor types under conditions of styrene overloading

“…A number of studies have been conducted on this application, using both common bioreactor types, i.e., biofilters (BFs) with low water usage (Li and Moe 2005) and their opposite, trickle-bed bioreactors (TBRs), which may be called in situ bioscrubbers . These studies laid a sound foundation for designing the bioreactors featuring sufficiently high residence times (low air flow rates) (Bastos et al 2003;Chang and Lu 2003;Atoche and Moe 2004;Mathur and Majumder 2008) and using appropriate mineral feeds and packing materials for various substrates in different reactors (Song et al 2003;Li and Moe 2005). However, two significant barriers to success exist for a wide use of biofiltration for the treatment paint booth off-gases.…”