Wet oxidation is the oxidation of soluble or suspended components in an aqueous environment using oxygen as the oxidizing agent. When air is used as the source of oxygen the process is referred to as wet air oxidation (WAO). The oxidation reactions occur at temperatures of 150°C to 320°C (275°F to 608°F), and at pressures from 10 to 220 Bar (150 to 3200 psi). The required operating temperature is determined by the treatment objectives. Higher temperatures require higher pressure to maintain a liquid phase in the system.