Between 2008 and 2012, HOCHTIEF Solutions designed and built a wastewater treatment plant for the city of Rousse in Bulgaria. The municipal facility near the Romanian border has a capacity of 52,500 cubic meters a day, enough to treat the wastewater of 240,000 people. The water is first roughly cleaned mechanically, before being treated chemically and finally biologically. The energy from any biogas produced is recovered. Due to the facility’s location on the Danube, HOCHTIEF took precautions to protect the site from flooding while the work was in progress.