DISTRIBUTION OF WATER IN SLUDGES IN RELATION TO THEIR MECHANICAL DEWATERING

The water content of a sludge is generally considered to be constitute d by two fractions: free water and bound water. This classification do es not, however, characterize the binding energy of water to the solid phase. By using the dilatometric technique, the bound water content o f sludge was measured as a function of the mechanical dewatering strai n applied to the sludge. Thus, it was possible to separate water into different categories (free water, bound water removable by moderate me chanical strain, bound water removable by maximal mechanical strain, b ound water not removable mechanically), depending on its behavior duri ng mechanical dewatering.