The Investigation of the Parameters Affecting the Solubility of Waste Activated Sludge in the Electro‑oxidation Process

Since the beginning of the last century, there has been a high demand for renewable energy sources due to the decrease in fossil-based energy sources and the intense pollution of these energy types. Bioenergy recovery from sludge biomass is an attractive renewable energy source. Electrochemical treatment is one of the investigated physicochemical methods to increase methane production from waste activated sludge (WAS) biomass. It can be used as a new and efficient pretreatment for the hydrolysis of WAS. In this study, electrochemical technology with platinum/titanium (Pt/Ti) mesh electrodes was first applied for WAS before aerobic digestion. The effects of various operating conditions such as current intensity and initial pH of the sludge were investigated. The study showed that the amount of soluble COD of WAS increased with increasing current intensity. In addition, the results obtained showed that pH values higher or lower than the pH value of WAS (6.2) are favorable for the degradation of organic substances. An approximately 358% increase in COD solubility was detected at the end of the reaction time of 30 min at a current intensity of 25 A. The conducted study showed that electrochemical pretreatment is feasible and that increasing the methane production rate for anaerobic digester-containing wastewater treatment plants in Turkey has the potential to provide environmental and economic benefits.