MANOMETRIC DETERMINATION OF BIOLOGICAL DEGRADABILITY OF SUBSTANCES POORLY SOLUBLE IN AQUEOUS ENVIRONMENTS

Several ways or methods of testing the biological degradability of org anic substances poorly soluble in aqueous environments were verified b y applying manometric BOD measurements. Model substrates employed here were dibutyl phthalate, dioctyl adipate, bio-fuel and some of their c omponents. Dosages of substrates were varied by combining direct weigh ing and sonification, by using an emulsion with Triton X100, or by a s olution in 1,1,2-trichlorotrifluoroethane. These selected variants of dosage, except for the last, proved to be equivalent from the viewpoin t of degree and rate of biological degradation. The applied methods ga ve values of biochemical/theoretical oxygen demand ratio (BOD/ThOD) ar ound 50%, even for substrates claimed to be biologically easily degrad able. (C) 1997 Elsevier Science Limited.