ABSTRACT

Sludge conditioning is a process whereby sludge solids are treated chemically or various other ways to improve the dewatering of sludge. Sludge conditioning is achieved through artificial methods, viz. by vacuum or press filters or by centrifuges. Conditioning can be accomplished either by chemical methods, in which organic or inorganic flocculating chemicals are used, or physical methods using heat and freezing to change the characteristics of the sludge. Particle size plays an important role in sludge dewaterability, since the chemical addition enhance the size of particles and decrease the bound water. Ferric salts are the most common coagulants used for conditioning the sludge to be dewatered by vacuum filtration. Intimate admixing of sludge and coagulant is essential for proper conditioning. Polyelectrolytes have found increased utilization for sludge conditioning, even for pressure filtration where inorganic chemicals were traditionally preferred. The oxidative method differs from the nonoxidative one by the fact that the former uses air for the sludge treatment process.