The information regarding the biological degradation of PPCPs has been added in the introduction. The revised sentences are shown below: In the BAC biofilters, the biotransformation and adsorption both contributed to the PPCPs removal. The activated carbon adsorbed PPCPs to the surface and interior, where microorganisms were suitable for growth. Under the long-term effect of high-concentration PPCPs, the dominant microorganisms in the biofilter were selected to survive. These microorganisms mostly transformed PPCPs into many segments and even directly mineralized them to CO2 [3, 14].
The authors should include some information regarding the biological degradation of PPCPs by microorganisms in the introduction section.