Supercritical Water Oxidation of Wastewater and Sludges – Design Considerations

The SCWO process is a promising technology for the treatment of industrial wastewaters and sludges. The commercial or industrial development of this technology mainly goes through engineering considerations, such as reactor design, solids separation and equipment corrosion. In this paper, state of the art of these topics and the flow sheets and energy and mass balances for diluted wastewater and sludge treatment are presented. This plant simulation has been done using the software ASPEN PLUS and it shows that the SCWO process is an interesting alternative from the energetic point of view. The energy integration of a SCWO plant for 2 m³/h sludges with a heating value of 23000 kJ/kg can produce 420 kW as mechanical work and 2522 kg/h of process steam (0.3 MPa). For diluted wastewater the process is autothermal for feeds with an enthalpic content of 900 kJ/kg.