Abstract: A filter system with a deep bed filter of microbeads is provided. The filter system may include a mixed bed trickling filter that utilizes microbeads as a high specific surface area media for biofiltration, capture of fine particulate solids, as well as degassing and oxygenating. Mixing devices, such as mechanical stirrers, axial flow pumps, airlift pumps or helical screws, may be integrated to enhance the mixing of the bed and to prevent clogging. Degassing or oxygenating process may be integrated within the microbead filter to introduce or withdraw gases in the bed. In a particular embodiment, the filter system includes serial distribution plates, which support multi-layered beds that create separate chambers in a filter vessel. Degassing or oxygenation process may be integrated within each microbead filter chamber.