Removal of N and P in a Rotating Biological Contactor Plant: Case Study Agnita, Romania

The wastewater treatment plant of Agnita, Romania was designed with a rotational biological contactor system for population approximately 9500, but environmental protection reasons it must comply regulations concerning nitrogen and phosphorus larger communities. In order to achieve the prescribed limits these pollutants, we have used 40% FeCl3 solution, continuously added distributor, without changes in flow or equipment. Its use boosts removal ammonia nitrogen, phosphorus, bringing them within reasonable cost. To determine ferric chloride be considered, aside from pollutant load, water temperature, introduced new parameter: specific power that enabled us optimize volume FeCl3. A major contribution achieved by denitrification bacteria favored presence ions, which also precipitate phosphorus. results this study, performed since September 2021, enable continue method enlarge its application other plants owned local operator.