Biodegradation of phthalic acid esters by acclimated activated sludge

The microbial degradation by acclimated activated sludge of three phthalates, priority pollutants listed by both the China National Environmental Monitoring Centre and the U.S. EPA, i.e., dimethyl (DMP), di-n-butyl (DBP), and di-n-octyl (DOP) phthalate was investigated. The experimental results demonstrated that DMP and DBP with the shorter alkyl-side chain phthalic acid esters (PAEs) can be rapidly degraded—nearly 90% within 3 d for DMP and 8 d for DBP. However, the degradation rate of DOP was slow. The degradation of PAEs can be described by the first-order reaction model. The first-order rate constants (k₁) of three PAEs determined in this study can correlate with the corresponding second-order hydrolysis rate constants (K_OH).