The February issue of “Hydro” is online. The special coverage “Desalination and reverse osmosis”, on page 18, is the main focus of this issue, showing that the water crisis in the country has aroused interest in the desalination of sea water for public supply. A large project is about to become reality in Fortaleza, CE, in partnership with the private sector. See on page 28 the article “Ash and iron composites as a biofilm support medium in a biological filter”, a study that analyses the use of heavy ash from mineral coal burning in a thermoelectric plant for the production of a sintered ceramic composite. The material can be used as biofilm support medium in domestic sewage after treatment. Furthermore, on page 36, the article “Potential of rainwater harvesting in the Southeast Region”, assessing the potential of rainwater harvesting as an alternative non-potable source, based on the determination of urban water demand in the capitals of the Southeast region and the rate of monthly rainfall. This issue brings also the updated “Dosing pumps”, “Chemical products for water and wastewater treatment” and “Mechanical equipment for water and wastewater plants” buyers’ guides.