A device includes a compartment for separating the solids and liquids. The compartment includes a base that is concavely curved according to a cylindrical portion having a transverse axis and is formed of a sieve, an idler roller mounted transversely on an arm, a drive which actuates the arm, and resilient means for adjusting the pressure exerted by the rollers. Both the contact interface between the sieve and the roller and the rotational interface between the roller and the arm are made of a non-metal material on at least one of the two contacting surfaces that form each of the interfaces, such that, there is no metal-on-metal contact between surfaces moving relative to one another at the interfaces.
