Polyvinyl alcohol is a water-soluble synthetic polymer. It is used in papermaking, textiles and variety of coatings. It is white and odorless. It is supplied a beads or as solutions in waste. PVA is used as an emulsion polymerization aid, as protective colloid, to make polyvinyl acetate dispersions. PVA recovery system helps to recover 90 per of the PVA out of the waste liquor which in turn saves 50 per of the cost. PVA is used as yarn size formulation to achieve required yarn performance properties during weaving. Using 100 per, PVA formulations for certain fabrics significantly increases COD or BOD levels compared to starch and also presents opportunities for reclaiming and reusing size. The COD in waste PVA is very high and reached approx 40,000ppm.
By recovering the PVA, COD in the waste water is reduced by around 80 per, the remaining, which can easily be treated by an ETP Plant. The recovered PVA is then sent to a pressure sand filter where it forms a cake, which is then dissolved in acid to keep PVA in liquid form.