A filter press is a device that is used to filter, or clean, wastewater produced by industrial sources or residential uses. The purpose of the filter press is to produce water as an end product that can be reused by the original consumer. The wastewater will typically contain elements that will be described by the term "sludge" that need to be removed, or filtered out, of the water.
Filter Cloths
Siemens is a major manufacturer of filter presses, having years of experience in the production and proper use of the product to obtain the desired goal of reusable water. In its section of frequently asked questions, the company explains filter cloths come in many sizes, and are made with different materials. The type of filter cloth required is based upon the type of filter press and the desired outcome. Each owner of a filter press has to assess their own requirements and then determine the filter press needed. Siemens provides general guidelines, but clearly state that each filter press must be fitted on an individual basis.
Dewatering
Durco is another manufacturer of filter presses for "dewatering," or separating the liquid sludge from the solid sludge, known as "filter cake." Durco makes two basic products to reduce, or remove the sludge, with the process involving the liquid sludge passing through the filter cloths, while the filter cake remains in the press, to be emptied as a solid once the process is complete, Durco lists the wide range of industrial and municipal uses for its product.
Belts
Another product to reduce sludge through a filter press involves the use of belts, hence the term belt filter press. This product, sold by Komline-Sanderson, utilizes mechanical pressure to reduce the sludge by positioning it between two or three belts. The sludge then goes through a series of rollers, with the pressure from the belts producing a solid sludge which is discharged from the belt filter press.