The efficiency of solid/liquid separation may be improved significantly by using synthetic polymers as flocculation aids. Flocculation may be caused by the interparticle collision or by reducing the particle electric load. This paper presents the synthetic flocculation aids having the role of blocking (cationic and anionic polyacrylamides), action mechanism, factors affecting flocculation (charge, effect of shear, effect of particle size, effect of stock consistency, effect of polymer molecular weight, effect of pH, effect of temperature and charging place). The experimental part shows the effect of using some cationic and anionic polyacrylamides in the paper making process. Improvement of physico-mechanical and optical paper properties as well as reduction of suspensions in waste water by over 50% are noticed.
