Comparing the Effects of Deep and Surface Aeration Methods on Density and Type of Airborne Bactria and Fungi in Municipal Wastewater Treatment Plant

نویسندگان

  • Ghazi, Mona Assistant Professor, Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
  • Yazdanbakhsh, Ahmadreza Professor, Workplace Promotion Health Resaerch Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran Professor, Despartment of Environmental Health Engineering, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran
  • Abtahi Mohasel, Mehrnoosh Assistant Professor, Department of Environmental Health Engineering, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran
  • Zare Bidaki, Maryam MSc Student in Environmental Health Engineering, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran
چکیده مقاله:

Background and purpose: Emission of bioaerosols from wastewater treatment plants is a potential hazard to human health. In this study aimed at investigating the effects of surface and deep aeration techniques on density and type of airborne bacteria and fungi in two municipal wastewater treatment plants. Materials and methods: This descriptive cross-sectional study was done in two wastewater treatment plants in Tehran equipped with surface and deep aerations. Microbial samples were taken from air beside aeration tank, grit chamber, secondary sedimentation basin and two control points (upwind and downwind) every 6 days during summer and autumn 2017. Samples were analyzed for density of bioaerosols and types of bacteria and fungus applying standard methods. Results: Wastewater treatment plant with surface aeration tank had the greatest effect on emission of bioaerosols than the plant with deep aeration. Mean values for density of bacterial bioaerosols and fungal emission were 6845 and 15784 CFU/m2/h in summer and 535 and 899 CFU/m2/h in autumn, respectively. Different gram-positive and gram-negative bacteria were identified in both wastewater treatment plants investigated. Conclusion: According to current study, emission of bioaerosol in wastewater treatment plants with surface aeration is more than that of those with deep aeration and has greater potential hazard.  

برای دانلود باید عضویت طلایی داشته باشید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

the effects of keyword and context methods on pronunciation and receptive/ productive vocabulary of low-intermediate iranian efl learners: short-term and long-term memory in focus

از گذشته تا کنون، تحقیقات بسیاری صورت گرفته است که همگی به گونه ای بر مثمر ثمر بودن استفاده از استراتژی های یادگیری لغت در یک زبان بیگانه اذعان داشته اند. این تحقیق به بررسی تاثیر دو روش مختلف آموزش واژگان انگلیسی (کلیدی و بافتی) بر تلفظ و دانش لغوی فراگیران ایرانی زیر متوسط زبان انگلیسی و بر ماندگاری آن در حافظه می پردازد. به این منظور، تعداد شصت نفر از زبان آموزان ایرانی هشت تا چهارده ساله با...

15 صفحه اول

on translation of politeness strategies in dialogues involving female characters in translations and retranslations of novels translated before and after the islamic revolution of iran and their effects on the image of women: a polysystem theory approach

abstract reception environment has considerable effects on accepting a translation. as the expectations of a target culture and its values and needs change throughout history, its criteria for accepting a translation or rejecting it will change accordingly (gentzler, 2001). the expectations of iran, as the reception environment in the present study, have changed after the islamic revolution. i...

the effects of planning on accuracy and complexity of iranian efl students’ written narrative task performance

this study compared the different effects of form-focused guided planning vs. meaning-focused guided planning on iranian pre-intermediate students’ task performance. the study lasted for three weeks and concentrated on eight english structures. forty five pre-intermediate iranian students were randomly assigned to three groups of guided planning focus-on-form group (gpfg), guided planning focus...

15 صفحه اول

the effects of previewing and providing background knowledge on iranian university efl learners’ comprehension of literary and academic texts

abstract poor reading comprehension can result in failure in using references, benefiting from professional gatherings and resources, keeping up with the growing body of knowledge in the virtual world of the internet, and failing to achieve in efl programs. the purpose of the present quasi-experimental study was to explore the effects of background knowledge and previewing narrative and expos...

15 صفحه اول

on the comparison of keyword and semantic-context methods of learning new vocabulary meaning

the rationale behind the present study is that particular learning strategies produce more effective results when applied together. the present study tried to investigate the efficiency of the semantic-context strategy alone with a technique called, keyword method. to clarify the point, the current study seeked to find answer to the following question: are the keyword and semantic-context metho...

15 صفحه اول

منابع من

با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

ذخیره در منابع من قبلا به منابع من ذحیره شده

{@ msg_add @}


عنوان ژورنال

دوره 29  شماره 174

صفحات  121- 133

تاریخ انتشار 2019-07

با دنبال کردن یک ژورنال هنگامی که شماره جدید این ژورنال منتشر می شود به شما از طریق ایمیل اطلاع داده می شود.

کلمات کلیدی

کلمات کلیدی برای این مقاله ارائه نشده است

میزبانی شده توسط پلتفرم ابری doprax.com

copyright © 2015-2023