The May/June issue of “Hydro” is online. This special edition features on page 18 a preview of “Fitabes – International Fair of Environmental Sanitation Technologies” (May 21st to 24th), one of the largest environmental sanitation technology fairs in Latin America, where more than 200 exhibitors will show the latest innovations in technology to an estimated audience of more than 8 thousand visitors. Simultaneously, the 32nd CBESA – Brazilian Congress of Sanitary and Environmental Engineering takes place. See on page 34, the article “Artificial intelligence in WTP”, showing that, as a solution to comply with the legislation of an WTP located in a remote area, a study was carried out with online physical - chemical and microbiological tests, which allowed the automation of its process of monitoring the water quality. Furthermore. on page 50, the article “Nitrogen removal in sanitary sewage treatment”, presenting some possibilities, such as the process of simultaneous nitrification and denitrification (NSD), the use of aerobic granular sludge (AML), the anammox process (anaerobic oxidation of ammonia) and, more recently, comammox (complete ammonia oxidation). This issue also brings the update “Pressure reduction valves”, “Water storage tanks“ and “Water flow meters” buyers’ guides.