Removal of phosphorus and chemical oxygen demand from excess sludge supernatant using of ultrasound waves

The use of ultrasound is one of the most studied methods in treatment of water and wastewater. This study was going to remove pollutants from the supernatant of excess sludge by using of ultrasound. Initial raw supernatant with COD equal to 1600 mg/L and phosphorous equal to 80 mg/L was exposed to ultrasound. The experimental design was used to determine the experiments with variables including time (1.5-9.5 h), ultrasonic power (40-360 w), and the volume of sample (20-180 mL). COD and phosphorous were the responses, those were investigated in this research. Based on the Response Surface Methodology (RSM), a model for COD and phosphorous removal was obtained with a 95 % confidence interval. The optimized removal of COD (97.39 %) and phosphorous (98.73 %) was observed. According to the results, ultrasonic waves is a good way to remove COD and phosphorus from sludge. This method can be used in wastewater treatment plants for treatment of supernatant of excess sludge.