A belt press for use in removing water from sewage sludge, and including a frame, a pair of belts for compressing sludge material therebetween, the said belts being water-permeable whereby water in said sludge may drain through said belts, and a gravity belt thickener adjacent the belt press. The gravity belt thickener includes a belt having a belt flight adapted to support sewage sludge thereon, the belt of the gravity belt thickener having a width greater than the width of the belt of the belt press.

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