Wastewater treatment with renewable energy

Porvoon vesi is an enterprise owned by the city, which supplies its customers with household water and directs and treats wastewater. The City of Porvoo’s wastewater is treated in Hermanninsaari, which functions as the main treatment plant and where the wastewater from all primary zones is directed.

The Hermanninsaari wastewater treatment plant recovers heat from the wastewater, using it for heating the premises. In addition, solar panels have been installed on the roof of the plant, producing electricity for the plant. In 2018, a total of 31,119 kWh of energy was received from the solar panels.

The most energy in the treatment process at the plant is used in the aeration of the wastewater. Hermanninsaari has adopted aeration control, which allows for only the optimal amount of air to be fed for the treatment process.