Biological risk associated to bio-treatments: monitoring and modeling bacterial dispersion into the atmosphere in a soil bioremediation plant and in a wastewater treatment plant

Abstract

Wastewater is a mixture of domestic, municipal and industrial waste dissolved in water. The biggest fraction of wastewater is sanitary sewer water. Before its release in rivers or sea, water must be cleaned and all harmful bacteria must be killed. Biosolids are nutrient-rich organic waste obtained following wastewater treatment and used beneficially as fertilizer. Routinely, biosolids are deposited in agricultural areas or incinerated. For this reason the level of microbial pathogens in the biosolids must be limited. Nowadays, while human population increases, the question of safety managing and disposal of biosolids is becoming more and more important. Traditional bio-engineering based methods of cleaning polluted water and soil are not always safe for human population and may involve some level of risk. Airborne particulate matter (PM) is a complex and dynamic mixture of organic and inorganic substances of different chemical, physical and biological origins in the atmosphere. The biggest fraction of airborne particulate matter is represented by airborne microorganisms as bacterial cells, endotoxins, fungal spores and viruses. Bioremediation plants contain a big amount of different microorganisms that can become aerosolized in the atmosphere during different steps of treatment procedures. These microorganisms cause different infections in plant workers and affect the population living in surrounding areas. Some bacterial species like E.coli, Clostridium perfringens, and Enterococcus spp. are quite pathogenic and are of part