Removal of Color and Chemical Oxygen Demand (COD) from Textile Effluent

This review discusses the methods for the removal of dyes from the textile effluents. The textile effluents contain synthetic dyes which cause a potential hazard to the environment hence these dyes need to remove from the water bodies. The various dye removal techniques are classified into Chemical, Physical, and Biological methods. Physical methods includes adsorption, ion exchange, and filtration/coagulation methods etc. while chemical methods includes flotation and filtration, precipitation- flocculation with Fe(II)/Ca(OH)2, electro-coagulation, conventional oxidation methods by oxidizing agents (ozone), irradiation, electro-flotation or electrochemical processes and biological methods include aerobic degradation, anaerobic degradation, biosorption etc. Electro-coagulation treatment using iron and aluminum electrodes found to be very effective method among the all available dye removal methods and also effective for COD removal. Dyes from the industrial effluents are effectively separated by using electro-coagulation however its cost restricts the use in small scale applications. The results showed that dye and chemical oxygen demand removals were 92% and 91% and it can be concluded that electro-coagulation process is very efficient and clean process for reactive dye removal from coloured wastewater.