Textile Wastewater Treatment and Recycling

Abstract

Textile industry consumes huge quantities of fresh water (100–150 l/kg of cotton for direct dye). During various stages of textile processing, wastewater is charged with substantial amounts of chemical pollutants. Direct discharge of these effluents into the environment causes irreversible ecological problems. Effluents coming from the different steps of dyeing cycle can be collected separately for a further treatment at source or simultaneously to be treated using a traditional treatment process. Various technologies are developed to reduce environmental damage. The most used technologies are Conventional Activated Sludge (CAS) and coagulation-flocculation (CF). However, color and salt removal from textile wastewater by means of these technologies still a major problem. Membrane processes represents a better alternative for the treatment and reuse of such wastewaters due to their capability to produce a water quality, in conformity with the more and more strict legislation in place. Microfiltration and Nanofiltration used separately or combined together have been found to be the most successful treatment methods. Various aspects will be discussed regarding the methodology and process adopted to enhance the efficiency of the treatment including the treatment at source which can be a good alternative. Also, several examples will be given.