Facts
Otto Bachmann operates a fur processing facility in Bottenwil. The domestic wastewater and that from his business flow into the Uerke. On June 1, 1966, the Building Directorate of the Canton of Aargau issued a decree prohibiting the discharge of industrial wastewater from Bachmann's business into the Uerke as of October 1, 1966. A further decree dated November 22, 1966 postponed the enforcement of the wastewater discharge prohibition until May 1, 1967.
On June 12, 1967, the Building Directorate granted Bachmann permission to discharge the treated domestic wastewater into the Uerke. The "Special Conditions and Requirements" of this permit stated that the industrial wastewater situation should be regulated by the construction of a new building within the sewer district.
On October 3, 1969, the Public Prosecutor's Office brought charges against Bachmann for violating the Water Protection Act, as he was alleged to have continued discharging industrial wastewater into the Uerke after October 1, 1966. The District Court of Zofingen acquitted Bachmann, as it assumed that the further discharge of industrial wastewater was either tolerated by the authorities or permitted by an "informal but written authorization" until the municipal treatment plant was put into operation.
On appeal by the Public Prosecutor's Office, however, the High Court of the Canton of Aargau convicted Bachmann of continued intentional violation of the Water Protection Act. It assumed that the prohibition of November 22, 1966 had remained in effect after May 1, 1967, and that Bachmann had violated it at least with conditional intent.
Considerations
The Federal Supreme Court overturned the judgment of the High Court. It concluded that the High Court had violated Bachmann's right to be heard by not considering his offer of evidence to support his claim that he had been orally and in writing authorized to continue discharging the industrial wastewater.
The Federal Supreme Court stated that, in accordance with the principle of good faith, informal…