A pump arrangement for a chamber filter press 1 for dewatering sludge. The pump arrangement is intended for delivering conditioned sludge from a mixing container to the chamber filter press 1. It contains at least two piston pumps 2, 3 which are connected to a common delivery line 4. The pistons of the piston pumps 2, 3 are mechanically connected 5 to one another in such a way that the two pistons move 180 DEG out of phase. <IMAGE>
