The present study was aimed at evaluating the air microflora on the premises of the sewage treatment plant Kapuściska in Bydgoszcz and in the surrounding area, and was conducted with the use of the sedimentation and impaction methods. The analysis reveals that mould fungi were the most abundant, followed by mesophylic heterotrophic bacteria. Actinomycetes and mannitol-positive staphylococci constituted the least abundant group. The highest counts of the studied microorganisms (with the exception of staphylococci) were determined at Site III, located between the aeration tanks and the bioreactor, which are considered to be the main emitters of microbial aerosol contamination. The concentration of microorganisms decreased considerably with distance from the source of microbial aerosol emissions.
The following genera prevailed among the mould fungi: Penicillium (54%), Aspergillus (23%), Cladosporium (11%), Fusarium (6%), Alternaria (3%), and others (3%).