Abstract: Process for the removal of metals, in particular heavy metals and strontium, from waste water in the form of their sulfide by mixing the waste water with a water soluble sulfide. According to the invention the metal containing waste water is thoroughly mixed with the water soluble sulfide at a suitable pH in a reactor of the fluidized bed type, which is provided with an appropriate bed material, on which the metal sulfide crystallizes out, whereby the thus obtained bed material provided with crystalline metal sulfide is removed from and new bed material is added to the reactor from time to time. Usually as water soluble sulfide an alkali metal sulfide or alkali metal hydrogen sulfide or ammonium sulfide or FeS is used, whereas the use of sodium sulfide, sodium hydrogen sulfide, potassium sulfide or potassium hydrogen sulfide is preferred. According to the present process a.o. the following metals: Ni, Sr, Zn, Cu, Fe, Ag, Pb, Cd, Hg, Co, Mn, Te, Sn, In, Bi or Sb may be removed.

Abstract: Heterogenous nucleation on a seed material is promoted in the removal of phosphate from water by contacting the water with the seed material in a bed of grains of the seed material which bed is fluidized and kept in fluidization by the water stream itself, while the introduction of the reagent or reagents is effected so as to have a substantially complete heterogenous nucleation take place on the seed material.

Abstract: A dredging vessel, specifically intended for the dredging of rivers or similar water courses, equipped with propulsion means allowing the vessel to move independently through the water; an adjustable suction line, with suction head, connected to the suction side of a pump installed in the vessel; and a discharge pipe, connected to the delivery side of the pump, rotatable about an approximately vertical axis and terminating in a nozzle with adjustable passage opening.

Abstract: A filter tube for drain purposes provided with openings debouching at its outer surface, said openings being adapted to be connected to a sub-atmospheric source through at least one discharge channel in the tube. At least one flush-channel is formed in the tube, which is fully separated from the discharge channel(s) and which is adapted to be connected to a source of pressure fluid at or adjacent the one tube end, while at or adjacent the other tube end an outlet for said pressure fluid is formed.