Patent ID: 7811458

Claim:
A method for the dewatering of sludge including negatively charged particles obtained from rivers, harbors, the sea floor, or sandbanks, comprising adjusting the concentration of the sludge to a pumpable concentration by addition of water, flushing the sludge through a pipeline to a dewatering field, mixing the sludge with an aqueous solution of a polymeric flocculating agent while it is being transported, allowing the sludge to settle in the dewatering field to form a sediment and partly freeing the sludge of supernatant and/or drainage water and then subjecting the sludge to natural evaporative drying, wherein the polymeric flocculating agent is a water-soluble, anionic, polymeric flocculating agent that contains from 5 to 30 percent by weight of anionic monomer units and has a weight-average molecular weight Mw of higher than 1.0×10 7 .