Novel Phosphorus Recovery from Sewage Sludge Using Supercritical Water Gasification

Abstract

The aim of this work is to develop a new phosphorus recovery from sewage sludge using the supercritical water gasification treatment. The experiment was carried out using a laboratory scale continuous reactor under several temperatures in the range of 350-600 ⁰C. The pressure was kept at 25 MPa and varying residence time in the range of 5- 30 s. It was found in this study that the phosphate ions could be collected as precipitate in the supercritical water gasification and phosphorus could be successfully recovered and separated from the organics. Surprisingly, phosphorus was released to the liquid phase in inorganic form much before the completion of gasification. This behavior of phosphorus was expressed in the reaction model incorporated with the precipitation model. The model fit well with the experimental result.