LAUSR

Abstract This work aimed to improve sludge disintegration and nutrient solubility using synergism of a surfactant (sodium dodecylbenzene sulfonate (SDBS)) and ultrasound. The results illustrated that the critical micelle concentration (CMC) of the surfactant (0.025 g SDBS/g total solid (TS)) was significantly related to the cost-effective pre-treatment performance. The particle sizes of Dx(10) and Dx(50) were decreased from 16.4 μm and 55.4 μm to 3.69 μm and 12.9 μm, respectively, under a 600 W ultrasound input with the CMC of SDBS. As the surfactant dosage was further increased (0.05 SDBS g/g TS), the maximum increment rates of total nitrogen (TN) and total phosphorus were obtained at 1250.1% and 197.1%, respectively. However, higher pre-treatment efficiency could be achieved when SDBS was below the CMC. It related to the decrease of surface tension. Based on the economic evaluation, the total cost significantly increased when the amount of surfactant was greater than the CMC.