Ultrasound assisted enzymatic pre-treatment of high fat content dairy wastewater

• Ultrasound used for the intensification of enzyme pretreatment of dairy waste water.
• Effect of various parameters on ultrasound assisted enzyme catalyzed reaction of fat was studied.
• COD was decreased from 42,400 ppm to 11,250 ppm with 73.5% removal efficiency.
• Ultrasound alone significantly reduce the reaction time by 97%.

This paper illustrates the application of ultrasound in a dairy waste water treatment for the removal of fat using enzyme as a catalyst. Lipase Z was used to perform the enzymatic pre-hydrolysis of a synthetic dairy wastewater containing around 2000 mg/L of fat content coupled with ultrasound irradiation. Different process parameters like effect of enzyme loading, temperature, ultrasound power, frequency, duty cycle and speed of agitation are optimized. The maximum hydrolysis of 78% is achieved at 0.2% enzyme loading (w/v), 30 °C temperature, 165 W of ultrasonication power at 25 kHz and 66% duty cycle. It was observed that the enzymatic pre-hydrolysis under the influence of ultrasound drastically reduces the reaction time from 24 h to 40 min as compared to conventional stirring with improved yield.