The intention is to provide an introduction to Filter Press technology as it applies to sludge dewatering and filtration and provide the basic facts for an understanding of these processes.

Introduction

Sludge dewatering using filter presses has become accepted as a reliable and efficient method of dewatering effluents and sludges from industrial and municipal waste treatment processes.  Some typical applications include:

* Metal hydroxide sludge

* Brine sludge

* Secondary biological sludge

* Water treatment alum sludge

* Oily sludge

One of the most difficult problems today is the disposal of sludges in waste treatment. Dewatered sludges from traditional dewatering equipment, (i.e. rotary vacuum drum filters, centrifuges and belt presses), are less acceptable for disposal in landfills and due to their high moisture content they are not economical feasible. The filter press process results in drier sludge that has proven to be an effective solution to this problem.

For example – sludges (such as alum sludge and waste activated sludge) that were previously considered difficult to dewater on traditional equipment can now be dewatered in a filter press sufficiently to produce a hard, dry, easily handled and autogenous material for incineration.

The Filter Press

The filter press basically consists of a number of chamber filter plates (also referred to as recessed filter plate pack) mounted vertically on and between two sidebars or suspended from an overhead support beam. The support beam or sidebars are connected at one end to a fixed head, also known as a feed head, and at the other end to a closing head. Through a closing arrangement on the closing head, usually a hydraulic ram, the recessed filter plate pack is compressed tightly together between the fixed feed head an a third head know as the moving or follower head, thus forming a compact filtering unit using recessed chamber filter plates or flush plates and frames.