Effects of Caustic Recovery on Pollution and Cost of Production in a Cotton Textile Industry

Textile manufacturing industry is uses substantial amount of chemicals not only in the production processes but also in manufacturing the raw materials. Chemicals used in textile production are generally classified as commodity chemicals and speciality chemicals. Former are used in Bulk and the later are used in small quantities. Caustic Soda (Sodium Hydroxide) is one of the major chemicals which are used in large quantities for producing cotton textiles. Caustic soda results in highly alkaline waste water from the textile mills which makes the effluent toxic and poses difficulty in treatment of effluent. This study to assess the impact of caustic recovery from the mercerization plant was conducted in a cotton fabric manufacturing unit. A pilot scale single effect evaporator was used to concentrate the effluent stream from mercerization process and the changes in the quality of effluent and concentration of caustic lye were studied over a period of one year. In addition to the improvements in the quality of effluent, the study has also focussed on the cost savings in terms of effluent treatment and production due to reuse of the recovered caustic.