Abstract: A plant for conditioning and dewatering a suspension comprises a belt press, centrifuge or other continuous dewatering apparatus (3), a flow-line (1) leading to the dewatering apparatus, a pump (2) for causing suspension to flow along the line (1), means (5-9) for dosing conditioner into he suspension at a dosing point (4), means (12) for measuring density D, means (10) for measuring the flow rate V and thereby for calculating the dry mass per unit time M, and control means (16, 17, 18) for automatically dosing a mount A of conditioner into the suspension where A-kM and k is a constant and for automatically varying V in response to D and for automatically varying the constant k in response to D.

Abstract: The addition of polymeric flocculant or other chemical dewatering modifier to a suspension flowing through a service line to a dewatering plant is controlled automatically in response to automatic determination of a filtration rate parameter. This may be determined using novel apparatus which includes a filtration assembly comprising a chamber with a filter element mounted across its open end and water sprays for washing the filter element. In one embodiment it is preferred to assist back-washing with an air purge while in another embodiment there are means for disassembling the filtration assembly to permit cleaning.