The belt filter is an industrial machine, used for solid/liquid separation processes, particularly the dewatering of sludges in the chemical industry, mining and water treatment. The process of filtration is primarily obtained by passing a pair of filtering cloths and belts through a system of rollers. The system takes a sludge or slurry as a feed, and separates it into a filtrate and a solid cake.
The belt filter is mainly used for dewatering of sludge and slurry and juice extraction from apples, pears and other fruits, as well as grapes for winemaking, etc. Belt filters are used both municipally and industrially in a range of areas including urban sewage and wastewater treatment, metallurgy and mining, steel plants, coal plants, breweries, dyeing, tanneries, as well as chemical and paper factories.
The applications of a belt filter are only limited to the sludges, slurry or mashed fruit that it can process. The sludges from municipal use include raw, anaerobically digested and aerobically digested sludges, alum sludge, lime softening sludge and river water silt. In industry, any sludge or slurry is sourced from food processing wastes, pulp and paper wastes, chemical sludges, pharmaceutical wastes, industrial waste processing sludges, and petrochemical wastes. These wastes can include mixed sludge, mineral slurry, dust sediment, selected coal washing mud, biological sludge, primary sludge, and straw, wood or waste paper pulp.
Some dewatering objectives include reducing the volume to reduce the transport and storage costs, removing liquids before landfill disposal, reducing fuel requirements before further drying or incineration, producing adequate material for composting, avoiding runoff and pooling when used for land applications, and optimizing other drying processes. Belt filters are specifically designed for each of these particular applications and feeds.