Bioaerosols in a sewage treatment plant

What is it about?

Sewage treatment plants emit microbial contamination in the form of bioaerosols to the atmosphere mainly from wastewater. Due to differentiated aeration and mixing of wastewater in the bioreactor, air samples were taken for microbiological analysis from the central part of the bioreactor above the sewage surface of the nitrification and denitrification chambers. In each of these chambers a test stand was set, located at the height of 20, 50 and 100 cm above the sewage surface, which enabled direct sampling of air (bioaerosol) at the designated altitude. From the same biological reactor chambers (nitrification and denitrification), in which the bioaerosol was tested, sewage samples were also collected from the near - surface layer.

Featured Image

Why is it important?

The emission of microorganisms in the atmosphere is influenced by the type of a chamber in which sewage is located. It was found that the process of mixing, aeration of wastewater, have an effect on the emission of microorganisms. In order to assess the degree of the emission of microorganisms from the wastewater into the air, the so-called percentage emission ratio ER was calculated. Bearing in mind the fact that the microorganisms from the wastewater penetrate the air as a result of an intense turbulence, overflow and aeration of the wastewater, as well as the effect of wind and convective air movement on the border between liquid and gas phase (wastewater / air), it has been calculated that the percentage of the microorganisms in the bioaerosols coming from the sewage (percentage emission ratio) is only a fraction of a percent.

Perspectives