Biocathodes of bioelectrochemical system(BES)could enhance reduction of nitroaromatics,halogenated aromatics and azo dyes.However,specific substrate enrichment is usually needed for the startup and the process is time consuming.To establish a non-specific biocathode at a short time,polar inversion from anode to cathode has been proposed to acclimate electroactive biofilm that can catalyze different aromatic compounds reduction.Once start-up of bioanodes within about 12 days,they were directly used as biocathodes for nitrobenzene(NB),acid orange 7(AO7)reduction and antibiotics chloramphenicol(CAP)reduction after a short acclimation.