Effects of chloramphenicol on the bacterial community structure and simultaneous nitrification and denitrification performance in a sequencing biofilm batch reactor

•CAP had different inhibitory effects on nitrification and denitrification in SBBR.•The SOUR, nitrifying, denitrifying rate of the biofilm declined under CAP stress.•The CAP removal amount increased with influent CAP concentration.•Differences in bacterial community structure were observed due to CAP.