It is becoming increasingly urgent to investigate the partition coefficients (expressed as log KDOC values) of polybrominated diphenyl ethers (PBDEs) in dissolved organic carbon (DOC) present in wastewater. In the current study, after 72 h of equilibration, the concentrations of four common PBDEs were measured in the presence of four DOC solutions from two laboratories and two full-scale anaerobic digestion plants. Sixteen log KDOCs were determined by calculation and unit conversion. The results for the laboratory samples, such as log KDOCs for 2,2',4,4',5,5'-hexabromodiphenyl ether being 6.38 and 5.46 at different reaction temperatures during the cultivate procedure, suggest that a thermophilic environment promotes the solubility of PBDEs to a greater extent than mesophilic conditions. DOC composition directly influences the solubility of PBDEs, even at the same cultivating temperature: the highest log KDOCs for 2,2',4,4',5,6'-hexabromodiphenyl ether were 6.71 and 6.33 in different full-scale plant digestates. A linear regression with an R2 of 0.9863 was used to construct a model describing the potential relationship between log KDOC and the composition of DOC, which includes proteins, polysaccharides and lipids, and which takes into account the positions of bromine atoms, for use in predicting the log KDOC values of PBDEs in different water systems.
Keywords: Anaerobic digestion; Dissolved organic carbon; Partition coefficient; Polybrominated diphenyl ethers; Simulation.
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