Effective waste water management in colouration of polyester using Bio-shell microcapsules

The present work aimed at efficient utilization of resources viz. , water, dyes and chemicals (without using any supportive chemical) for colouration of polyester. Disperse dye microcapsules were prepared using the method of complex coacervation. Bio-shell coated microcapsules of disperse dyes were analyzed for their resource efficient auxiliary chemicals free colouration on polyester (PET) over conventionally dyed one. The remnant liquor recovered from colouration of polyester was recycled for subsequent four colouration cycles (without treatment) showing acceptable shade difference. The remnant liquor obtained from fourth colouration cycles treated with basic primary water treatments and was found to be translucent, neutral in pH and low effluent load (TDS > 231 ppm, BOD > 114 mg/l, and COD > 469 mg/l). The solids recovered from bath were analyzed and found to be nontoxic (LD 50 ,> 8000) as well. Cost involved in microencapsulated colouration (USD $ 6.48) is lower than that of conventional process of colouration (USD $ 8.40). Thus, microencapsulated colouration is easily adoptable in existing process line of polyester colouration, which leads to small liquid discharge of low.