Effect of Low-intensity Ultrasound on Cd Tolerance of Partial Nitrification Sludge

Abstract

Abstract Cadmium (Cd) is a typical nitrification inhibitor, which has a strong inhibitory effect on partial nitrification (PN). The discrepancy on Cd tolerance of PN sludge caused by low-intensity ultrasound (LIU) was studied. It suggested that the half inhibitory concentration (IC50) of sludge was increased from 24.51 to 29.07 mg/L by 35 days of ultrasonic treatment, and the Cd tolerance of sludge was enhanced. Further analysis indicated that contents of extracellular polymeric substances (EPS) rose substantially because of LIU, which played a catalytic role on increasing adsorption capacity of PN sludge for Cd.