Classification and Dewatering of Sludges

Abstract

The disposal of dredged sediments has become an ecological problem in Hamburg as well as in other seaports since these sediments have turned out to be contaminated with heavy metals (Table 1). The traditional solution of using the dredged sludge for filling up low marshland is no longer accepted by the public. The port authorities are therefore forced to look for alternative solutions to this problem, the dimension of which is obvious from the quantities which have to be dredged annually. In the fairways and harbour basins of the port of Hamburg about 2.5 million m³ of mud and sand have to be dredged per year (Christiansen et al. 1982) and the corresponding figure for Rotterdam is of the order of 20 million m³. Facing this problem Hamburg’s port authorities have initiated a research program, the Hamburg Dredged Material Research Program, in the scope of which the reasons and origin of sedimentation and the contaminations in sediments as well as alternative methods for treatment and deposit of harbour mud are being investigated (Christiansen et al. 1982).