Novel pilot scale photocatalytic treatment of textile & dyeing industry wastewater to achieve process water quality and enabling zero liquid discharge

This paper presents a novel end-to-end pilot scale photocatalytic treatment of real textile & dyeing industry effluent, which involved innovative approach in primary treatment, followed by Heterogenous Photocatalysis (HP) involving nano-TiO2/UV as secondary treatment and suitable filtration leading to treated water meeting process water quality enhancing water re-use efficiency. This enables Zero Liquid Discharge (ZLD); which is the need of the hour in tackling problems of point source pollution and Water Conservation in developing countries like India. Overall treatment led to complete degradation and mineralization of organic pollutants and dye stuff thereby achieving adequate treatment, complete decolourization and deodorization of the effluent and almost hundred times less quantities of sludge residues in comparison to those obtained in conventional treatment methods. The nature and elemental composition of sludge residues, as investigated using Energy Dispersive Xray (EDX) elemental analysis, confirms complex organic dye components mineralized and nature being nontoxic. The complete treatment took place in 5 h without any kind of bioremediation method, which further highlights highly efficient and fast treatment coupled with small footprint. Overall cost of treatment is estimated to be around 1.55 USD/m(3). Such an innovation in wastewater treatment is expected to bring a revolution in developing countries, which are grappled together with problems of rapid industrialization, urbanization, regulatory compliances and environmental challenges.