ABSTRACT
I. THE PROBLEM OF SURFACTANTS (1959-1964) In 1959, German rivers were foaming. After the long dry summer, the MBAS level of drinking water from the Ruhr River increased at domestic taps to as much as 1.73 mg/liter in the city of Essen on December 21, 1959. Downstream
of dams massive and stable foam layers formed (Fig. 1). In canal locks barges disappeared in the foam. Long foam trails like condensation formed behind barges on the Rhine. The (few) biological sewage treatment plants with activated sludge processes produced foam barriers a couple of meters tall, which were blown by the wind into the surrounding water (Fig. 2).
