866 J ournal of Sabzevar U niversity of Medical Sciences February & March 2017. Vol 23. Num 6 * Corresponding Author: Hamza Ali Jamali, PhD Address: Department of Environmental Health Engineering, School of Public Health, Qazvin University of Medical Sciences, Qazvin, Iran. Tel: +98 (912) 3819051 E-mail: jamalisadraei@yahoo.com Research Paper Applicaton of Response Surface Methodology (RSM) to Optmize Coagulaton–flocculaton Process for Treatment of Metal Working Fluids Using Calcium Chloride and Ferric Sulfate 1. Assistant Professor, Department of Environmental Health Engineering, School of Public Health, Hormozgan University of Medical Sciences, Bandar Abbas, Iran. 2. MSc. Student, Department of Environmental Health Engineering, School of Public Health, Qazvin University of Medical Sciences, Qazvin, Iran. 3. Assistant Professor, Department of Environmental Health Engineering, School of Public Health, Qazvin University of Medical Sciences, Qazvin, Iran. Kavoos Dindarloo 1 , Ali Arezoumand 2 , *Hamza Ali Jamali 3 Backgrounds The current study aimed at optmizing the coagulaton-focculaton process to treat metal working fuids (MVF) by calcium chloride and ferric sulfate using response surface methodology (RSM). Methods & Materials The removal efciencies of chemical oxygen demand (COD), turbidity, and the amount of released oil via coagulaton process using calcium chloride and ferric sulfate as coagulants were studied. Central Composite Design (CCD) and RSM were used to optmize the operatng variables including coagulant dosage and pH. Quadratc models were developed for the 3 responses of COD, tur- bidity, and released oil from MWF. Results The results of the current study indicated that the optmum conditons were calcium chloride dosage of 4 g/L at pH 3.5. The COD, turbidity removal efciency, and oil releasing from MWF were 93%, 96.9%, and 31.8 mL, respectvely and the level of desirability was 91.2%. Optmum conditon for ferric sulfate was 6.5 g/L at pH 4.5. The COD, turbidity removal efciency, and oil releasing from MWF were 62.1%, 93.6% and 13.7 mL, respectvely and the level of desirability was 91%. Conclusion Coagulaton-focculaton process using calcium chloride, compared with conventonal coagu- lants such as ferric sulfate, was very efectve on pollutants removal. Calcium chloride usage was 35% less than common coagulant while removal efciency was greater. A B S T R A C T Keywords: Metal working fuid, Coagulaton- foccu- laton, Calcium Chlo- ride, Ferric Sulfate, Response surface methodology Received: 29 Aug. 2016 Accepted: 19 Dec. 2016 Use your device to scan and read the artcle online Citation: Dindarloo K, Arezoumand A, Jamali HA. [Application of Response Surface Methodology (RSM) to Optimize Coagulation–flocculation Process for Treatment of Metal Working Fluids Using Calcium Chloride and Ferric Sulfate (Per - sian)]. Journal of Sabzevar University of Medical Sciences. 2017; 23(6): 866-875. http://dx.doi.org/10.21859/sums-2306866 : http://dx.doi.org/10.21859/sums-2306866