Do full-scale gas-phase biofilters reduce or increase bioaerosol emissions?

Area of Science:

• Environmental Microbiology
• Air Pollution Control
• Biosafety Assessment

Background:

• Biofilters are crucial for treating odorous gases, but their biosafety requires evaluating bioaerosol emissions.
• Understanding the origin and characteristics of bioaerosols is essential for assessing real-world biofilter applications.
• Previous studies have not fully elucidated the contribution of packing material versus inlet air to bioaerosol emissions.

Purpose of the Study:

• To investigate the characteristics, size distribution, and sources of bioaerosols from full-scale biofilters over a 12-month period.
• To assess the impact of biofilters on bacterial emissions and potential pathogenicity.
• To determine the contribution of biofilter packing material versus inlet air to overall bioaerosol emissions.

Main Methods:

• Collected bioaerosols from the inlet and outlet of three full-scale biofilters.
• Analyzed packing material microbiome composition.
• Characterized bioaerosol size distribution and quantified emissions over a year-long period.

Main Results:

• Over 96% of bioaerosols originated from the inlet air, not the biofilter packing material.
• Full-scale biofilters reduced bacterial emissions by 5-17% and lowered potential pathogenicity.
• Despite reduction, residual bioaerosols with potential pathogenicity were primarily linked to inlet air sources.

Conclusions:

• Biofilters effectively reduce bioaerosol emissions and associated risks, but inlet air remains a significant source of potential pathogenicity.
• Evaluating the biosafety of biofilters necessitates a thorough consideration of upstream processes and their contribution to bioaerosol load.
• Targeting upstream emission sources is crucial for enhancing the overall biosafety of biofilter applications in odorous gas treatment.