Pilot-scale biofiltration at a materials recovery facility: The impact on bioaerosol control

Area of Science:

• Environmental Engineering
• Microbiology
• Air Pollution Control

Background:

• Materials Recovery Facilities (MRFs) generate bioaerosols, posing potential health risks.
• Effective bioaerosol control is crucial for public health and environmental safety in waste management.

Purpose of the Study:

• To evaluate the performance of pilot-scale biofilters in removing specific bioaerosols from MRF waste airstreams.
• To assess the impact of inlet concentrations and gas residence time on biofilter efficiency.

Main Methods:

• Utilized a six-stage Andersen sampler to quantify bioaerosol concentrations (Aspergillus fumigatus, total fungi, total mesophilic bacteria, Gram-negative bacteria) before and after biofiltration over 11 months.
• Monitored biofilter performance under varying inlet concentrations typical of waste treatment facilities.

Main Results:

• Achieved average removal efficiencies of 70% for Aspergillus fumigatus, 71% for total fungi, 68% for total mesophilic bacteria, and 50% for Gram-negative bacteria at high inlet concentrations.
• Observed high variability and potential net emission at low inlet concentrations; gas residence time showed no significant impact.
• Outlet air contained a higher proportion of smaller, respirable particles, though overall concentrations were low.

Conclusions:

• Biofilters designed for odor control can significantly reduce bioaerosol concentrations in waste airstreams.
• Performance is dependent on inlet bioaerosol load, with potential for net emission under low load conditions.
• Biofilters offer a viable strategy for bioaerosol management in materials recovery facilities.