Wet oxidizer for the treatment of anaerobic offgas in sewage treatment plants for odor removal and disinfection, for example behind biological and denitrification stages. Suitable for the removal of mercaptanes in digesters and anaerobic pumping stations. Optionally equipped with AOP an system for the cracking of aromatics. The system has a self-sucking water jet to avoid the use of a ventilator and to improve the consumption of energy. The oxidation principle does not need any chemicals and is fully sustainable.