Iran Nanotechnology Initiative Council participated in the 7th Iran International Water and Waste Water Exhibition which was held in Tehran\'s Permanent International Fairground from September 5 to 8, 2011.Expanding the applications of nanotechnology in water and wastewater industry, facilitating the presentation of products to the market and exchanging technical knowledge between the Iranian and foreign researchers in the field of nanotechnology were among the Iran Nanotechnology Initiative Council\'s objectives for taking part in the exhibition. By participating in the Seventh Iran International Water and Wastewater Exhibition, Iran Nanotechnology Initiative Council and the companies Vahid Industrial Group and \"Water Treatment Alchemists\" introduced the applications of nanotechnology in water and wastewater industry, including the use of nanoparticles in water purification, nanofiltration, and also the nanomembranes that are able to adsorb heavy metals. In addition to introducing the applications of nanotechnology in water and wastewater industry, Iran Nanotechnology Initiative Council presented two plans for the provision of drinking water for the city of Molasani by using nanofilters and the establishment and implementation of a pilot plant for the nanofiltration of Karoon River water in Southern Iran. Participation in the Seventh Iran International Water and Wastewater Exhibition was the sixth participation of Iran Nanotechnology Initiative Council in specialized exhibitions in 2011. Among other specialized exhibitions in which Iran Nanotechnology Initiative Council took part in the present year, mention can be made of the Eleventh International Exhibition of Building Construction, the Third International Exhibition of Energy Saving and Urban Electronic Management and the Nineteenth International Exhibition of Ceramics and Porcelain.