Comparison of the conventional chemical coagulation process and electrocoagulation and flotation efficiency in cosmetics industry wastewater treatment

Background: Cosmetic and personal care industry wastewater contains chemicals and nonbiodegradable organic compounds that must be treated before discharge into the environment.This study aimed to compare the efficiency of conventional chemical coagulation and electrocoagulation-flotation processes in treating wastewater from the cosmetic industry.Materials and Methods: In this experimental study, both processes were designed using a central composite design (CCD) approach.For the chemical coagulation process, the variables optimized included pH (5-9), rapid mixing time (30-60 sec), slow mixing time (10-20 min), settling time (30-60 min), and the dose of the coagulant (0.5-1 g/L).For the electrocoagulation process, the optimized variables were pH (5-9), direct current intensity (2-4 A), reaction time (40-80 min), the number of electrodes (4-8 n), and the distance between electrodes (2-4 cm).Results: In both processes, the designed model followed a quadratic model with a high correlation coefficient.The efficiency of the electrocoagulation process in reducing COD levels in cosmetic industry wastewater was significantly higher than the conventional chemical coagulation process.Under optimal conditions, the COD concentration decreased from 570 mg/L to 57 mg/L in the electrocoagulation process.In contrast, the conventional chemical coagulation process achieved 65% efficiency under optimal conditions, reducing COD levels to 199.8 mg/L. Conclusion:The results indicated that after treatment using the aforementioned processes, the effluent can be safely discharged into the environment.