Efficiency of Coagulation and Flocculation Process Combined with Chemical Sequestration in Removal of Organic and Inorganic Contaminants from Aautomotive Industry Sewag

Introduction: The most important environmental problem of automotive industries is the produced wastewater due to its various processes. The flocculation and coagulation along with chemical sequestration are among important processes for removing contaminants from wastewaters. The aim of this study is to investigate the efficiency of coagulation and flocculation process along with chemical sequestration in the removal of organic and inorganic pollutants from automotive industry sewage. Study Method: This study is an applied-experimental study. The removal of organic and inorganic substances by coagulation, flocculation process combined with chemical sequestration was carried out in batch reactors. The parameters turbidity, heavy metals' concentration, color, phosphate, coagulants concentration, exposure time, TSS, pH and COD were studied. The concentration of color and residue of heavy metals were determined using spectrophotometer -UV and atomic absorption. Results: The research results showed that the removal percentage of Cr, Ni, Pb and Zn by ferric sulfate combined with lime at a pH equal to 10 and the exposure time of 100 minutes were 52.65, 96.3, 3.27 and 100 respectively, and percentage of removing them by aluminum sulfate combined with lime was 52.65, 97.8, 3.37 and 99.81 respectively. the removal percentage of TSS, COD, color, turbidity, phosphates ferric sulfate was also 68.9, 83, 94, 84 and 47.2 respectively, and this amount of removal by aluminum sulfate was 62, 80, 94, 73.5 and 48 respectively at neutral pH and concentration of coagulant was obtained equal to 150 mg / L. Conclusion: According to the results, the use of coagulation and flocculation process combined with chemical sequestration in the removal of organic and inorganic pollutants in wastewaters of automotive industry achieved under optimal conditions is very effective and can be used in water treatment of automotive industry.