A sludge dewatering system comprising a moving foraminous belt (10) having a horizontal conveying run on which sludge is carried to permit drainage of water therefrom through the belt. In accordance with the invention a row of deflectors (12) are mounted on a pivotal cross beam (13) extending over the belt (10). Each deflector has a leading edge (19) and a pair of diverging and upwardly concave walls (21) whereby sludge proceeding along the conveying run of belt (10) is divided overturned and compressed by the deflectors.