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Background: Bioaerosol is defined as airborne particles such as living organisms include bacteria, viruses, fungi and their related metabolites, such as endotoxin. The exposure to bioaerosols in the hospital may causes infection especially in immunocompromised patients. The purpose of this study was to investigate the Bioaerosol concentrations in air of various parts of three hospitals of Isfahan University of medical sciences, Iran. Methods: An Anderson biosampler was used for the bacterial and fungal collection. The effect of factors such as humidity, temperature and outdoor Bioaerosol concentrations were also evaluated. Findings: The lowest mean of fungal and bacterial concentration was observed in hospital operating rooms and the highest concentration was detected in infectious diseases ward of hospital 1 and 2 and surgery ward of hospital 3. Significantly, bacterial levels were found to be higher in hospital wards than outdoor; except hospital operating roo. Conclusion: Our results show that bioaerosol concentrations in hospitals were relatively high and in particular, the higher levels of bacteria than outdoor might be related to the presence of patients, their activity, unsuitable ventilation and disinfection. Therefore, environmental control measures are needed to assure hospital environmental quality especially in wards with immunocompromised patients.

In this study, experiments have been conducted to evaluate the organics and nutrients removal from synthetic wastewater by a laboratory scale moving bed biofilm process. For nutrients removal, moving bed biofilm process has been applied in series with anaerobic, anoxic and aerobic units in four separate reactors. Moving bed biofilm reactors were operated continuously at different loading rates of nitrogen and Phosphorus. During optimum conditions, close to complete nitrification with average ammonium removal efficiency of 99.72% occurred in the aerobic reactor. In the aerobic reactor, the average specific nitrification rate was 1.8 g NOx-N kg VSS −1 h −1 . The results of the average effluent soluble COD concentration from each reactor showed that denitrification process in the second anoxic reactor consumed most of the biodegradable organic matter. As seen from the results, denitrification rate has increased with increasing NOx-N loading in the second anoxic reactor. The aerobic phosphate removal rate showed a good correlation to the anaerobic phosphate release rate. Moreover, phosphate removal rate showed a strong correlation to the phosphate loading rate in the aerobic reactor. In optimum conditions, the average SCOD, total nitrogen and phosphorus removal efficiencies were 96.9, 84.6 and 95.8%, respectively. This study showed that the moving bed biofilm process could be used as an ideal and efficient option for the total nutrient removal from municipal wastewater.