A batch process for the treatment of an aqueous solution so that the treated product is more desirable for disposal includes obtaining an influent batch of aqueous solution for treatment, treating the batch of solution by an advanced oxidation process. The advanced oxidation process including causing ozone to be mixed with the solution, maintaining the mixture of solution and ozone at a pressure above atmospheric for a time of at least two seconds. In a preferred embodiment of the process, the process includes continuously recirculating the fluid to be treated, through a recirculation conduit, the recirculation conduit including an ozone injector and the ozone injector is adapted to inject ozone into the aqueous solution as the aqueous solution circulates through an ozone injector. Influent to be treated may be selected from the group including sewage, septage, leachate, ballast or other aqueous solutions where it is desirable to treat the fluid prior to disposal, further treatment, or reuse. The process is carried out to improve a level of disinfection and/or denutrification of the effluent.