Critical Evaluation of Some Available Treatment Techniques for Textile & Paper Industry Effluents: A Review

Abstract

The disposal of untreated effluents from the textile & paper industries is a major environmental concern these days. Textile effluents are colored & contain carcinogenic aromatic amines, dyes, organic & inorganic molecules. However, paper mill effluents are dark in colour due to the presence of wood extractives, lignin, resins, tannins, synthetic dyes & their degradation products. Both textile & paper industry wastewaters are characterized by extreme fluctuations in many parameters such as pH, color, temperature, suspended solids, biological oxygen demand (BOD), chemical oxygen demand (COD), adsorbable organic halides (AOX) & salinity. The recycling of wastewater of textile & paper industries has thus been recommended due to the high levels of contamination in dyeing and finishing processes. So this review discusses the various methods of treatment available in the literature for textile and paper industry effluents. Use of low cost adsorbents obtained from various plant materials such as neem leaves, bark of babul & maize corn carbon (MCC)are highly encouraged for the decolorization of aqueous solutions of dyed effluents of industries because they are not only cost effective but sometimes more efficient than the commercially available activated charcoal. A combination of anaerobic-aerobic treatments to effluents of textile and paper industries has been found to be more economical & effective in terms of reduction of pollution. Also the degradation of dyes by mixed cultures has been found to be more effective than those of the individual strains of microorganisms. Among all these methods, advanced oxidation processes are the most promising treatment techniques these days as these processes can be used to oxidize the more complex organic compounds without production of any secondary components to be handled.