Biotreatments of odours: control and performances of a biofilter and a bioscrubber

Abstract

Biotechnology has been applied to find systems to decrease the level of pollution. The main biological systems used in the deodorisation of waste gases are biofilters, biotrickling filters and bioscrubbers. These technologies work at normal operating conditions of temperature and pressure, and therefore they are relatively cheap with high efficiencies when the waste gas is characterised by high flow and low concentrations of odorous compounds. The aim of this work was to study the influence of different parameters (residence time of the gas phase, pollutant loads) of a biofilter and a bioscrubber on removal efficiencies. Ethanol was used as pollutant compound, because it is representative of both volatile organic compounds and odorous molecules. The performances of the two biological systems are presented and discussed. The use of pressure drop monitoring as a tool to control the operation of a biofilter and to obtain optimal conditions in a bioscrubber is proposed.

Benzene vapor treatment using a two-phase partitioning bioscrubber: an improved steady-state protocol to enhance long-term operation

“…Since the operating policies of the TPPB now draw a closer resemblance to more traditional vapor-phase bioreactors, a direct comparison of these technologies for the treatment of benzene contaminated waste gases is more appropriate. The data of Table 3 reflect the fact that biofilters and trickling biofilters are typically best suited to treat high volume gases with low benzene content [19], since few of the feed concentrations exceed even 1 g/m 3 . In contrast, the influent benzene concentration averaged 5.6 g/m 3 for the TPPBs in this study.…”

Bioprocesses for air pollution control

“…96,97 Waste gases containing hydrophilic VOCs such as, for example, methanol can also be treated efficiently in bioscrubbers. 98 Several full-scale systems have been commercialized worldwide for the desulphurisation (H 2 S removal) of biogas, landfill gas and natural gas. 99 Another process, the BioDeNOx technology, has been tested for NO x removal from flue gas.…”

Direct Comparison of Fluidized and Packed Bed Bioreactors for Bioremediation of an Air Pollutant

“…Biological techniques can be highly effective for the treatment of VOC emissions, particularly for waste gas emissions with high volumetric rates and low contaminant concentrations (Le Cloirec et al, 2001). To mitigate these harmful effects, VOC emissions from point sources such as storage vessels or building ventilation ducting can be captured for treatment.…”

“…Biotrickling filters involve a continuous, recirculating stream of liquid that flows over packed bed media; these filters are very effective for treating waste gases that are water soluble and transfer easily from the waste gas to the liquid stream (Kennes and Thalasso, 1998). Biofilters are normally designed to treat superficial gas velocities from 0.014 to 0.042 m s -1 , with contaminant concentrations less than 5 g m -3 (Le Cloirec et al, 2001). For treating air contaminated with both soluble and insoluble substances, biofilters (packed beds where micro-organisms coat the packing) are already used in several industrial situations.…”

“…An external-loop airlift bioreactor was shown to be effective at treating the hydrophilic compounds ethanol and p-cresol (Wei et al, 1999). Le Cloirec et al (2001) investigated a biofilter of moist wood chips to treat 0.06 to 1.3 g m -3 ethanol in air. Biofilters are normally designed to treat superficial gas velocities from 0.014 to 0.042 m s -1 , with contaminant concentrations less than 5 g m -3 (Le Cloirec et al, 2001).…”