Kamaleddin Hosseinzadeh - Water and Wastewater Research Center, Applied Chemistry Department, Faculty of Chemistry, Razi University, Kermanshah, Iran
Mehdi Ghayebzadeh - Department of Environmental Health Engineering, School of Public Health, Kermanshah University of Medical Sciences, Kermanshah, Iran
Mehdi Shahi - Department of Environmental Health Engineering, Ardabil University, Ardabil, Iran
Zargam Hosseini - BSc in Health Environmental health centers of Ardabil city, Ardabil University of Medical Sciences, Ardabil, Iran

Flocculation is an important industrial process for solid-liquid separation during the primary purification of wastewater. Effects of the solution pH and flocculants dosage to examine the performance of five commercially available cationic & anionic polyacrylamides (Chemfloc 3876, Chemfloc 1510C, Chemfloc 530A, AN913 and AN913 SH), with different molecular weights and different charge densities to treating the tile factories wastewater were investigated. To minimize turbidity and total suspended solids (TSS), the experiments were carried out using jar tests, and response surface methodology (RSM) was applied to optimize this process. The optimal conditions for flocculent dosage and pH were determined 20 mg/l and 3-5.25, respectively, where 99.6% of TSS removal and final turbidity of 18 NTU could be obtained for Chemfloc 1510C. This paper shows that higher molecular weight polymers improved initial aggregation but the effect of cationic charge was more important for a stable flocculation. The results suggest that single-polymer system can be used alone in the coagulation-flocculation process due to the efficiency of the polyacrylamide.

flocculation, Polyacrylamide, Tile Industry Wastewater, Turbidity, RSM