
Special membranes are used for ultra filtration processes, the CBR or carbon block resin, filters that are micro porous ceramic, filters that are metallic alloy in nature and carbon filtering membranes are some of the filters that are activated by granules. Filtration methods of more than one kind are used in certain filters. Water used for drinking can be filtered in jug filters, built in filters in kettles etc for reducing build up of lime scale. Water filters of the portable kind are also used for filtering water. Many of the medical aid organizations, military forces, hikers etc make the best use of portable filters which are light in weight and small and work on a hand pump that can be used mechanically.