Experimental Studies on pre-treatment of sludge by combination of thermal hydrolysis and ultrasound and sand removal by hydrocyclone to optimize wastewater and sludge treatment

In this paper, experimental studies on pre-treatment of sludge by using the combination of thermal hydrolysis and ultrasound were carried by using Bioprocess bench scale system. A set of experiments were conducted under different periods for thermal hydrolysis at 120 degree and various intensity of ultrasound treatment, and under mesophillic and thermophilic conditions. The experimental results were analysed with obvious potential of enhancing sludge digestion efficiency with shorter digestion time and better biogas production. Many WWTPs in southern part of China were built up without primary sedimentation tanks, therefore sand comes into biological system, resulting into accumulation of sand in biological tanks and in waste-activated sludge before digestion. Experimental study on using hydrocyclone on the returned sludge stream has been tested to evaluate the efficiency of sand removal from MLSS to improve MLVSS/MLSS and potential impact on both biological system capacity and anaerobic digestion of sludge.