Two-stage separation process

A process is disclosed for producing an oxidized liquid effluent containing minimal dissolved gases therein, from a subcritical wet oxidation treatment system. The oxidation mixture exiting from the treatment system is separated into a first oxidized liquid effluent and a first gaseous phase as the mixture a first separator vessel operated at a relatively low superatmospheric pressure. Sufficient pressure is maintained in the first gaseous phase to provide the motive force for transport to further treatment or discharge. The first oxidized liquid effluent flows to a second separator vessel operated at essentially atmospheric pressure, where remaining dissolved gases separate from the first oxidized liquid effluent. The second gaseous phase is discharged and the second oxidized liquid effluent is suitable for storage or further treatment. Provision for adjusting the pH of the oxidized liquid effluent during the separation process is also disclosed.