Journal of North Khorasan

Abstract Background & Objectives: Biological aerosol term refers to airborne particles of biological origin, and includes a diverse range of microorganisms and living organisms. One of the major concerns associated with composting facilities is reproduction and distribution of biological aerosols in considerable quantities. The aim of this study was to determine the bioaerosols concentrations of the various units of the Tehran's Kahrizak compost plant and compare with standard concentrations. Materials & Methods: In this study, the total bacteria, Gram-negative bacteria and the fungus Aspergillus fumigatus in different parts of the plant using the direct method of sampling was tested. Sampling was performed during one month in four week of the field, separation unit, screening unit, mass windrow, 10 meters high (upwind) and lower mass windrow (wind direction). Results: The results of this study showed that the number of microorganisms in the field for total bacteria and gram-negative bacteria was respectively 791 to 1785 and from 12 to 135 CFU / m3 and for the fungus Aspergillus fumigatus 710 to 1000 CFU / m3. In samples taken from different processes to produce compost was reported the total bacteria and gram-negative bacteria was respectively, from 1250 to 2948 and 22 to 304 CFU / m3 and fungus Aspergillus fumigatus 796 to 1850 CFU / m3. Conclusion: The results of this study show that the biological aerosols from composting facilities units are further than the ASTM standards. This subject is remarkable in screening and separation units.