Under visse omstændigheder kræves der dog specifikke oplysninger om, hvordan et kemikalie reagerer over for forskellige metoder til spildevandsrensning, som f.eks. biofilm, nedsivnings- eller nedrislingsfiltre, roterende biologiske kontaktorer og fluide bede.
In some circumstances, however, specific information is required relating the behaviour of a chemical to methods of waste water treatment involving biofilms, namely, percolating or trickling filters, rotating biological contactors, fluidised beds. To meet this need various devices have been developed. 2. Gerike et al.