Sludge oxidation with peroxydisulphate: Effects on disintegration, anaerobic degradability and filterability properties

Abstract

usability of peroxydisulphate (PDS) oxidation for biological sludge obtained in municipal wastewater treatment plant for sludge disintegration prior to stabilization by anaerobic method was investigated. In addition, PDS oxidation has been evaluated as a conditioning process in order to improve the filterability properties of sludges. In this study, PDS oxidation was applied to sludges taken from Denizli Wastewater Treatment Plant where municipal wastewater is treated. Process conditions (concentration and temperature) were optimized using response surface statistical analysis in terms of disintegration and conditioning. Disintegration Degree (DD) for disintegration process and reduction in Capillary Suction Time (CST) are considered as efficiency for conditioning process. After determining the optimum conditions for the disintegration method, biochemical methane potential (BMP) tests were conducted to determine the anaerobic degradability of the sludge. The highest degree of disintegration (DD) was obtained when 900 g/kg DS concentration and 100°C temperature was applied and DD value was determined as 51.5%. This application enabled an increase of 42.6% methane gas compared to raw sludge. As a result of the study, It has been determined that oxidation process with PDS causes more methane gas formation in the anaerobic digestion process by providing disintegration of sludge. The lowest KES value was obtained in 1100 g/kg KM and 20 °C application, and the decrease in KES value was calculated as 89% in this application. This result showed that PDS oxidation improved the dewatering property of the sludges.