Region Olten, ARA Winznau
The Zweckverband der Abwasserregion Olten (ZAO) is an association of 13 municipalities which treat their wastewater in the WWTP Winznau. The WWTP itself was and is already the subject of refurbisching measures, but other structures in the sewer network also showed a considerable need for refurbischment, including pumping stations and storm water tanks.
