AN IMPROVEMENT IN EFFLUENT DISPOSAL WITH EMPHASIS ON COTTON PRETREATMENT PROCESSES

Environmental protection is becoming a serious concern for textile wet processors. In the dyeing and finishing industry, the pretreatment pr ocesses of cotton often cause serious ecological problems. The aim of this project was to reduce the effluent pollution of cotton pretreatme nt processes by modifying production processes and substituting proces sing chemicals that are more environmentally friendly. The desizing an d bleaching processes were selected since these are the essential pret reatments required before dyeing. For the desizing process, yeasts wer e introduced into the enzyme desizing system by different application methods to decrease the COD (Chemical Oxygen Demand) loading of the ef fluent. Peracetic acid was used as a replacement for the conventional bleaching agent, sodium hypochlorite, since sodium hypochlorite used i n bleaching gives a high AOX (Adsorbable Organic Halogen) value and fo rms chloroform in the effluent. The COD values of the effluent from th e peracetic acid bleaching process were investigated and compared with those from conventional bleaching processes based on sodium hypochlor ite or hydrogen peroxide.