Optimization of the energy consumption of the wastewater treatment plant in Castiglione T.se (NW of Italy)

The energy consumption represents a significant part of the operative cost of a wastewater treatment plant but, with a correct project and a careful management model, there are important possibilities for limitation. The proposed analysis concerns all the energetic aspects of the plant in Castiglione T.se (NW of Italy) that is the largest biological municipal wastewater treatment plant in Italy. The study takes into account every phase of the wastewater treatment scheme, in order to obtain specific electricity consumptions starting from a survey of the electrical devices operating in the plant: data from tele-control system, or direct readings and measurements in field have been used. By considering the obtained results, it is confirmed that the phase that uses the highest amount of energy is the biological wastewater oxidation, in consideration of the high electricity consumption arising from air compression and immission in the treatment tanks. Afterward the energy efficiency (by considering the obtained performances) of the used devices was calculated, and compared with literature and best practices indications. For the whole plant an energy balance has been performed, and some energy optimization solutions to decrease the corresponding cost were suggested.