Abstract:Aiming at intermediate autoxidation and bioactivity inhibition by hypersaline in anaerobic-aerobic biological treatment processes of azo dyes-loading wastewater, biodegradation characteristics of Acid Orange 7 (AO7) at the NaCl concentration of 100 g/L were investigated using some enhancement strategies. Addition of glucose (0.5g/L), peptone (1g/L) and yeast powder (0.5g/L) was propitious to the degradation of AO7 under hypersaline conditions. Biodecolorization rate of AO7 could be increased when acid red B was added to the anaerobic reactor. Anthraquinone-activated sludge self-immobilization system could enhance the biodecolorization of AO7 when anthraquinone was added to the salt-tolerant sludge and the maximal decolorization rate was about 92% at the anthraquinone concentration of 100mg/L. Addition of activated carbon felt as biological carrier allowed stable running of the anaerobic and aerobic reactors with a good sludge settlement and decoloration rate of 26.67mg/(L×h), and that the autoxidation of intermediate product 1-Amino-2-naphthol under aerobic condition could be inhibited effectively and over 90% of COD removal was maintained.