Heat pump at Utrecht sewage treatment plant

The Utrecht sewage treatment plant is located in the Utrecht neighbourhood of Overvecht. The old treatment plant was decommissioned and the new plant commissioned in May 2019. Every day, around 65 million litres of wastewater are treated at the plant. The wastewater that enters the plant is relatively warm because it is partly made up of shower water, hot tap water and water from dishwashers and washing machines. For this reason, even during a cold winter the temperature of the treated wastewater is 12 degrees, while in the summer it is 24 degrees. The residual heat from water is called aquathermal energy.

Thanks to the heat pump, the heat no longer dissipates. Instead, the temperature of the water is increased after treatment and the water is supplied to the heat network. A new 600-metre heat pipeline is being installed to connect the heat pump to the existing heat network. The cooled residual water will be discharged into the Vecht river.

The heat pump will be installed beside the pumping station on the site of the sewage treatment plant. The plant consists of a heat-pump building and two buffer vessels for heat storage.