Enhanced Removal of Phosphorus from Wastewater Using Sequential Electrocoagulation and Chemical Coagulation

An electrokinetic batch treatment scheme was investigated combining sequential electrocoagulation (EC) and chemical coagulation treatment (CC) processes. Synthetic and microbrewery wastewaters were tested in this investigation. The generated results demonstrated the capacity for the integration of EC-CC to effectively remove phosphorus contamination from wastewater under varying operating conditions. The effect of several operational parameters such as current density, conductivity, nutrient loading, and electrolysis time were investigated. The results showed that increased salinity can significantly accelerate the removal of phosphorous during EC treatment with 84.2% and 92.4% removal found for the applied power of 5 and 10 W, respectively. The addition of a sequential chemical coagulant stage following treatment by EC demonstrated the potential for an integrated EC-CC system to lower energy consumption while maintaining effective nutrient removal capabilities. Removal of phosphorous at 95% and 98% was achieved in just 10 min of EC treatment coupled with the addition of 15 mg/L aluminum sulfate. The estimated power consumption over a 10-min period was found to be 0.28 Kwh/m3 with a dissolution rate of 0.28 g/cm2 min held at a constant current density. The experimental anode dissolution rate for the synthetic wastewater ranged between 0.13 and 0.24 g/cm2 min encompassing all salinity levels. The anode dissolution rate increased during treatment of microbrewery wastewater with 0.67 g/cm2 min for 10 W EC treatment. This was attributed to the increase in current density and nutrient loading resulting in increased energy consumption and electrode passivation.