Abstract: Method for dewatering sewage sludge with the aid of organic polymeric flocculating agents (polyelectrolytes) made preferably by emulsion polymerization. To obtain optimum dewatering results, a substantial amount of the aqueous phase of the sludge is removed by decantation after flocculant addition prior to the dewatering treatment proper. The flocculated and thickened sludge may then be dewatered much more quickly with the dewatering behavior improved additionally by causing a reactivating flocculation to take place on the delivery side of the sludge feed pump. The Figures show a preferred embodiment of the inventive sludge dewatering system using a recessed plate press.