Journal of Health and Safety at Work

Introduction: Bioaeroslos released from wastewater treatment plants may contain pathogens existing in the sewage which could endanger the health of workers. The aim of this study was to evaluate the status of bioaerosol emissions form in a sanitary wastewater treatment plant.

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Material and Method: This cross-sectional study was carried out in different units of a sanitary wastewater treatment plant. For this purpose, air samples were collected on blood agar and dextro agar in an Andersen single-stage sampler with flow of 28.3 lit/min for 10 minutes. Collected samples were shipped to the lab immediately and incubated for 48 hours. Then, incubated samples were counted for colonies concentration.

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Result: Based on the result of this study, the mean density of bacterial and fungal bioaerosols in all wastewater treatment plants were 412.86±23.30 and 53.72±23.99 CFU/m³, respectively. Microbial contamination of the air within a kilometer away from the site (control areas) was 17 times less than its average density.

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Conclusion: Wastewater treatment processes can contaminate the air surrounding the plant, particularly with bacteria bioaerosols. Therefore, it is necessary to control the emissions and protect the health of workers against risks arising from exposure to bioaerosols.

Introduction: Harmful effects of environmental pollutants and their environmental impacts necessitate revention of the pollution emission from various industries. Leather industry is one of the most polluting industries, with chromium compounds as an important contamination, widely used in the tanning process. The present study aimed to determine the causes of high chromium concentration from leather production process in Charmshahr industrial complex in Varamin city.
 

Methods and material: Continuous sampling was done from the wastewater in each plant for six months and the contaminations resulted from different stages of leather products were investigated. In this regard, for determining the chemical quality and pollution load of wastewater from tannery process, following parameters were examined: PH, Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD), Total Dissolved Solids (TDS), Chromium (III), and Chromium (VI). Analysis of data was conducted by SPSS and Excel softwares. The t-test was used for comparison with standards at significance level of P<0.05.
 

Results: The results indicated the existence of toxic pollutants such as Cr⁺³ and Cr⁺⁶ in leather wastewater, the relatively high level of organic loads with low biodegradability, high levels of COD, BOD, TDS and finally the complexity of the treatment of wastewater.