REMOVAL OF AZO DYE (CONGO RED) FROM SYNTHETIC WASTEWATER BY COAGULATION

Abstract

The dissertation work deals with the reduction of Color and Chemical Oxygen Demand (COD) from synthetic waste water containing azo dye (Congo red) by the chemical precipitation using coagulation/flocculation method. Various coagulants like alum, ferric chloride, copper sulfate and ferrous sulfate were used to treat the waste water. Effect of various parameters Iike pH, coagulant dosage and flocculation time was studied and these parameters. were hence optimized. The effect of these parameters on settling behavior was studied. Alum and ferric chloride showed good results and gave up to around 97% and 78% in color and COD removal respectively. Effect of polyacrylamide, a polyelectrolyte, was also studied in enhancing the settling process of the particles (flocs) produced by the coagulation. The calculations for Sludge Volume Index (SVI), filterability study and sludge disposal study were carried out on the sludge samples obtained in the process. The characteristics of sludge were studied using Scanning Electron Microscopy (SEM), Energy Dispersive:X-Ray (EDX) and Fourier Transform Infrared Spectroscopy (FTIR).