Study on Biodegradation of Azo Dye by Thermophilic Anaerobic Process

Biodegradation of Reactive Red 2(RR2) by anaerobic process UASB was investigated under thermophilic condition such as 55 plusmn 1degC. The quasi-steady state of the UASB reactor was achieved after 92 running days when the conditions were as follows: hydraulic retention time (HRT) 12 h, salinity 50000 mg/L, COD 1000 mg/L, RR2 100 mg /L. The removal efficiencies of COD and RR2 were about 20% and 92%, respectively. High performance liquid chromatography (HPLC) and gas chromatography-mass spectrometer (GC/MS) were used to inspect the products generating during the degradation process of RR2, and the mechanism of RR2 removal was also revealed. The reductive cleavage of the azo linkage, which resulted in dye decolourisation and production of aromatic amine was brought about by thermophilic salt-tolerant anaerobic granular sludge and then some aromatic amines degraded through hydrolysis or oxidation and released NH₃.