fa بررسی تجزیه فرم‌آلدهید با کمک میکروارگانیسم های جدا شده از فاضلاب صنایع شیمیایی ایمنی Safety پژوهشي Research <p align="right">چکیده</p> <p> <strong> Background and aims </strong></p><p> <strong> </strong>Formaldehyde is one of hazardous compounds that may be found in waste water of different industries. This compound is toxic and biodegradation of it is difficult. The aim of this study is determination of efficiency of isolated microorganisms from polluted effluents by formaldehyde in aerobic and suspended and attached growth. </p><p> <strong> Methods </strong></p><p> <strong> </strong>In this study formaldehyde degrading microorganisms were separated from waste  water and soil in a chemical industry. Then microorganisms were isolated and separated by using special culture medias. 12 microorganisms were separated and used for biodegradation of formaldehyde. Standard method was used to evaluated of degradation value. </p><p> <strong> Results </strong></p><p>  The results showed that pseudomonas aeruginosa was the most effective microorganisms. COD removal efficiency of pseudomonas aeruginosa was 85% in suspended  growth and 83% in attached growth condition. Also removal kinetic parameters were calculated That μmax, K, Y, Ks and Kd coefficients were 1.44 l/d , 3.28 mg COD/mg MLSS.day, 0.44 28 mg  COD/mg MLSS. day, 1.36 mg/l and 0.04 l/day respectively. </p><p> <strong> Conclusion </strong></p><p>  Using aerobic conditions in this study to degrade formaldehyde and acceptable output reduction in the COD can be the advantages of aerobic exercises method in comparison  with anaerobic exercises. </p> فرم‌آلدهید ، تجزیه بیولوژیکی ، رشد چسبیده و معلق ، صنایع شیمیایی Formaldehyde, biological degradation, suspended and attached growth, Chemical industries 47 54 http://ioh.iums.ac.ir/browse.php?a_code=A-10-3-14&slc_lang=fa&sid=1 A. Joneidi احمد جنیدی جعفری moc.oohay@idinoj_damha 1360031947532846004175 1360031947532846004175 Yes IranUniversity of MedicaSciences, Tehran, Iran.l A. Talaee امیر رضا طلایی 1360031947532846004176 1360031947532846004176 No Faculty member of Civil Engineering of Jami Institute S. Jofee سهند جوفی 1360031947532846004177 1360031947532846004177 No Faculty member of Civil Engineering of Jami Institute M.M. Mehrabaniardakani محمد مهدی مهربانی اردکانی 1360031947532846004178 1360031947532846004178 No Iran University of Medical Sciences, Tehran, Iran.