Thermal treatment of waste activated sludge using liquid boiling

In this work we investigated the use of a short time, low superheat boiling process to treat biological sludge. The treated sludge would exhibit a deteriorated filterability, and a marked increase in soluble organics content. A large portion of extracellular polymers was released from the solid phase by boiling. The microbial density levels of the total coliform bacteria and the heterotrophic bacteria were reduced after treatment. Dilution in sludge concentration could allow more organic compounds to be hydrolyzed and a greater fraction of microbes to be disinfected when compared with the undiluted samples.