A review of polycyclic aromatic hydrocarbons and their substitutions in full-scale wastewater treatment plants

Wastewater treatment plants (WWTPs) become a main contributor of polycyclic aromatic hydrocarbons (PAHs) and their substitutions present in freshwater systems. This paper reviews PAHs and their substitutions in full-scale WWTPs including their fate and behaviors, analytical techniques, biological treatments, feasibility examination, and modeling. In addition, challenges and future outlook are also highlighted. This study found that PAHs and their substitutions have been detected in WWTPs. GC-MS and HPLC analytical methods have been found to be acceptable for the detection and analysis of PAHs and their substitutions. Although some biological treatments such as activated sludge and membrane bioreactors are capable for the treatment process, their technical, social, economic, and environmental aspects must be considered. The fate and treatability estimator (FATE) model has been used for the modeling of removal of PAHs in full-scale WWTPs, but in some cases their shortcoming has been reported, which calls for an evaluation and modification of the model based on physicochemical processes.