VOC elimination in a compost biofilter using a previously acclimated bacterial inoculum

Area of Science:

• Environmental microbiology
• Bioremediation technologies
• Air pollution control

Background:

• Volatile organic compounds (VOCs) like benzene, toluene, and xylenes pose environmental and health risks.
• Compost biofilters offer a sustainable approach for removing VOCs from contaminated air streams.
• Understanding biodegradation efficiencies is crucial for optimizing biofilter performance.

Purpose of the Study:

• To compare biodegradation efficiencies of specific volatile aromatic hydrocarbons in a compost biofilter.
• To determine the optimal moisture content for biofilter operation.
• To assess the impact of different pollutant mixtures and loads on removal efficiency.

Main Methods:

• A compost biofilter was inoculated with an acclimated microbial culture.
• The biofilter was exposed to synthetic and free-phase product mixtures of benzene, toluene, ethylbenzene, and xylenes at increasing loads.
• Inlet/outlet concentrations were monitored to calculate removal efficiencies and elimination capacities.
• Optimal moisture content was determined experimentally.

Main Results:

• Optimal moisture content for the biofilter was found to be 40%.
• High removal efficiencies (80-99%) were observed for most compounds in the synthetic mixture, except o-xylene.
• The biofilter demonstrated dynamic removal efficiencies (70-95%) for the free-phase product mixture, attributed to co-contaminants.
• Short acclimation periods (1-5 days) were noted due to the effective inoculum.

Conclusions:

• Compost biofilters are effective for biodegrading volatile aromatic hydrocarbons.
• An acclimated inoculum and optimized moisture content significantly enhance biodegradation performance.
• The presence of co-contaminants, such as chlorinated aliphatics, can influence removal efficiencies in complex mixtures.