Study On Biodegradation Of Azo Dye Acid Orange 7 (AO7) Stimulated By Low Intensity Ultrasound Radiation

The application of low intensity ultrasound in biological engineering is a hotspot, especially in the fields of fermentation engineering and food engineering in recent years. Until now, little is known about the application of low intensity ultrasound to pollutants treatment. This work contributes to the stimulation of low intensity ultrasound on the biodegradation process of azo dye Acid Orange 7 (AO7). The detailed information is as follows:(1) The optimum operation parameters of bio-ultrasound technique had been investigated. The stimulation effects were most obvious when bio-ultrasound reactor run with the optimum parameters as follows: ultrasound intensity 6.4 W L^-1, ultrasound frequency 25 kHz, influx glucose concentration 2000 mg L^-1, ultrasound exposure interval 5 min and air flux 0.4 mL min^-1. The results also showed the ultrasound radiation could increase the biodegradation rates of glucose and ABS which was a decolorization product of AO7.(2) The inhibition of high concentration NH₄⁺-N in aerobic biodegradation process of AO7 was investigated. The results showed that high concentration NH₄⁺-N could inhibit the bio-decolorization process of AO7, biodegradation of ABS and removal of COD. The Km and Vmax values were calculated on the basis of Michaelis-Menten equation. According to the Km and Vmax values, the NH₄⁺-N inhibition effects on the biodegradation of AO7 approximated a mixed inhibition model of noncompetitive and uncompetitive within initial NH₄⁺-N concentrations...