Hybrid filter unit

A hybrid filter unit, comprising.

• a housing with an inlet for input of a fluid to be cleaned and an outlet for output of the fluid in a cleaned state;
• a wall structure arranged inside of the housing defining a mixing chamber for the fluid, wherein the wall structure defines an inner cross section area that at least partly decreases in a direction from the inlet towards the outlet;
• a nozzle arranged to provide an oxidizing agent to the mixing chamber so that the fluid may be subjected to the oxidizing agent and react with the oxidizing agent as it flows between the inlet and the outlet;
• and
• a filtering structure arranged between an inner wall surface of the housing and an outer wall surface of the wall structure and wherein the filtering structure comprises volcanic Pumice wherein the wall structure is at least partly adapted for through-flow of the fluid from the mixing chamber to the filtering structure.