A group of researchers from Dhaka University and Sweden’s Uppsala University have made nano filters from Pithophora algae. Nano filters are cellulose filters. It is like white paper and the pores of the filters are 17 nanometers. Waterborne microbes are 30-100 nanometers. So all viruses and bacteria are trapped in the filter. It is possible to separate toxic arsenic, ions, salts etc. from water.