It consists of pumping the sludge, typically at a concentration of ~50g/l (0.5%), at a pressure between 6 and 18 bar, to a filter press.
A filter press is made of a series of plates, usually in polypropylene, which are covered by a filtration cloth, also typically in polypropylene thus creating chambers between each plate where the solids are retained and gradually dewatered under the pressure from the feed pump.
The resulting dry matter content of the sludge cake depends on the type of sludge, the quality of the flocculation and the operating pressure.
Metal hydroxide sludge at 13 bar and over can reach 35% to 40%, sludge with high calcium content (calcium carbonates, calcium sulphates etc.) can reach 60% dry matter content.
The filtrated water, whilst usually compliant, is typically returned to the clarified water processing or the inlet of the effluent plant.
The produced sludge cake can either be collected in a skip placed under the press or on a conveyor to be directed to a skip.
Nowadays, filter presses offer many options :
Review the fully automated emptying sequence of a press we recently installed :
"I would highly recommend Puretech Environmental as they provide excellent solutions, service and are always available to help you. The people are very well skilled and passionate about what they do, and this is clearly seen in their work - Five start rating"
