ABSTRACT
Water is the elixir of economic development providing energy, food, water supply to the population. Therefore, suitable quantity and quality are to be ensured for need-based use and application of water resources. With increasing demands for water supply and discharges of wastewaters, there is urgency of therapeutic actions to improve quality of water depending on use. Suspended and dissolved solids are to be removed from the water to attain the desired quality for defined use or consumption. Various physicochemical and biotechnological techniques are being employed to purify the water. In most of the techniques, the simplest mechanism used is filtration. It can physically or chemically aid biotechnologically accomplished filtration systems to remove undesirable substances. These filters are composed of various cellulosic, noncellulosic, sand, soil, plastic, and nonplastic materials. Various filtration mechanisms and techniques such as sand and soil filtration, bank filtration, pressure filters, carbondual-media filters, membrane filtration, ultrafiltration, nanofiltration, reverse osmosis, and so on have evolved in the last century. These filters are useful in treating the source water and water for residential areas, industries, and agriculture. They are also useful in treating the domestic and industrial wastewaters to comply with the stated discharge norms. Filters are inevitable in environmental technological applications in improving the water and wastewater quality.
