Abstract: The invention relates to a pulsed sludge bed settling method for treating all types of liquid, in particular water, and which uses at least one powder or grain reactant, according to which: the liquid and the reactant(s) for the treatment are contained in a tank (1) comprising, at the base thereof, a means (2) for uniformly feeding liquid to be treated over the entire surface thereof; the treated liquid is discharged into the top portion of the tank, at the top level (S) of the liquid; the liquid to be treated is supplied into the tank by pulsations, inducing alternating vertical movements of the sludge bed (M); and part of the sludge is spilled into a concentrator (12) when the top level of the sludge bed exceeds a spilling level (Ld).