Biotreatment of o-nitrobenzaldehyde manufacturing wastewater and changes in activated sludge flocs in a sequencing batch reactor

► SBR biotreatment of o-nitrobenzaldehyde manufacturing wastewater. ► Variables (SRT and HRT) were studied for the determination of kinetic constants. ► Changes of sludge flocs were studied by chemical analysis, FISH and DGGE. ► The results of DGGE profile analysis are in accordance with the FISH's, but more informative. ► β-Proteobacteria became dominant microbial population during adaptation.