Abstract: A novel process for treating a fluid is disclosed. Generally, the process utilizes a novel fluidized bed reactor and down flow filter. The process includes filling the reactor, and thereafter fluidizing the media bed contained therein. A catalyst is added, and the entire batch fluid is allowed to react with the catalyst. After appropriate settling of the media bed, the batch fluid is recycled. A filtration step is then included and appropriate disposition of the collected filtrate may be effected.