Treatment of Pulp and Paper Mill Wastewater With Cationic and Anionic Polyelectrolytes

The flocculation method has been used in treating the pulp and paper mill wastewater. the selectionof an appropriate polyelectrolyte for the treatment of wastewater is not easy as there is a large variety ofpolyelectrolyte available. the correct choice of polyelectrolyte is vital to get the best results. the flocculationperformance of nine cationic and anionic polyacrlayamide (organopol 5415, organopol 5020, organopol 5470,organopol 5450, organopol5540, chernfloc 1515c, chemfloc 430a, an 913 and an 913sh) with wide rangeof molecular weights and different charge densities have been used as flocculants to investigate theeffectivenessof the polyacrylamides in removal of turbidity,tss and codof wastewaters. organopol 5415 withhigh molecular weight and low charge density was the best flocculant with highest flocculation efficiency inthe treatment of the pulp and paper mill wastewater. at optimum dosage of smgr', 95% of turbidity removal,98% oftss removal, 89% of cod removal and svi of27ml.g-' were achieved. from the obtained data, it wasconcluded that use of a single-polymer system in the coagulation-flocculation process was very effective. theefficiency of the polyacrylamide was remarkable. sedimentation of the sludge by the gravity thickening with30 minute settling time was finalized, based on identified sludge settling characteristics.