Corrected first-order model of DEHP degradation

Corrected first-order model was applied to describe the biological removal of di-(2-ethylhexyl) phthalate (DEHP) in sludge-amended soil along with batch and continuous-flow anaerobic reactors with different initial/influent DEHP concentrations and hydraulic retention times. Only two kinetic parameters – the first-order rate coefficient k describing the overall kinetics of the process and the coefficient α characterizing the fraction of non-degradable DEHP – were used to fit the array of experimental data published earlier. The values of k and α estimated for DEHP removal from different sludges at 35 °C varied within the range of 0.03–0.07 d−1 and 0.25–0.5, respectively. In sludge-amended soil, the first-order kinetic coefficient k increased from 0.007 to 0.028 d−1 and the fraction of non-degradable DEHP α decreased from 0.6 to 0.5 with the increase in incubation temperature from 5 to 20 °C. The rate coefficient k increased by a factor of 2 when the temperature increased from 5 to 10 °C or from 10 to 20 °C.