Process and device for dewatering sludge, in particular mud from rivers, harbours or the like

摘要

It is known to divide the sludge pre-dewatered in centrifuges, sieve belt presses or the like into pellet-shaped lumps or mouldings, to encase the sludge mouldings with a layer of pulverulent drainage material such as ash and then to compress a bulk of these mouldings in a press and thus to give them a secondary dewatering, as a result of which high degrees of sludge dewatering are achieved. This known dewatering method with pressing of sludge lumps is efficient, in particular, if the sludge has a high content of compressible solids, which, for example, is the case with mud. In order, in the known dewatering process, to be able to produce the drainage material as simply as possible, according to the invention it is proposed that a fine sand fraction (15) is separated off from the sludge or mud (12) in a classifier such as a hydrocyclone (14), which fine sand fraction, if appropriate after dewatering (22) thereof, is used as fine-grained drainage material (23) for encasing the mud lumps. <IMAGE>