DIE ANWENDUNG DER DEHYDROGENASENAKTIVITAETSBESTIMMUNG IN UNTERSUCHUNGEN ZUM BIOLOGISCHEN ABBAU GRENZFLAECHENAKTIVER STOFFE.

The investigations with several surface active agents indicated that in the case of anionic surface active agents and in the case of well biogradable nonionic surface active agents the microorganisms of the activated sludge are adapted to such a great extent that with increasing residence time and simultaneous increase of the dosis of the surface active agent examined the biological degradation was enhanced. In the cases where the biological degradation was reduced after an initial period of an enhanced degradation, a supersensitive state of the microbes is supposed at that time, when the toxic dose is reached very soon. This observation was made with mixtures of nonionic surface active agents.