A rotary disc filter for filtering a liquid comprising: a rotary drum for receiving the liquid and having a plurality of openings formed in a surface thereof; a solids trough disposed in the drum and configured to receive a backwash and suspended solids mixture; one or more filter discs secured to the drum and configured to receive liquid from the drum and filter the liquid as the liquid flows outwardly from the filter disc through filter media forming a part of the filter disc; wherein the filter disc comprises a filter frame that supports the filter media on opposite sides thereof; the filter disc including a plurality of openings formed in an inner periphery of the filter disc; a drive for rotatively driving the drum and causing the filter disc to rotate with the drum; a backwash system for backwashing the filter media and including a plurality of nozzles disposed exteriorly of the filter disc and configured to direct the backwash through the filter media and into the filter disc where the backwash dislodges suspended solids from the filter media and a backwash and suspended solids mixture is formed; a plurality of backwash guides secured to or integrally formed with the filter frame and projecting inwardly from the filter frame into the filter disc, the backwash guides projecting inwardly from opposite sides of the filter disc into the interior of the filter disc and including elongated edges that angle inwardly with respect to the filter media; the backwash guides and a portion of the filter disc form a series of backwash channels that extend through the filter disc; wherein the backwash channels extend generally toward the openings in the inner perimeter of the filter disc; and wherein in a backwashing operation, the backwash channels are configured to receive at least a portion of the backwash and suspended solids mixture and to direct the backwash and the suspended solids to the openings in the inner perimeter of the filter disc where the backwash and suspended solids pass through the openings in the drum and into the solids trough. a rotary drum for receiving the liquid and having a plurality of openings formed in a surface thereof; a solids trough disposed in the drum and configured to receive a backwash and suspended solids mixture; one or more filter discs secured to the drum and configured to receive liquid from the drum and filter the liquid as the liquid flows outwardly from the filter disc through filter media forming a part of the filter disc; wherein the filter disc comprises a filter frame that supports the filter media on opposite sides thereof; the filter disc including a plurality of openings formed in an inner periphery of the filter disc; a drive for rotatively driving the drum and causing the filter disc to rotate with the drum; a backwash system for backwashing the filter media and including a plurality of nozzles disposed exteriorly of the filter disc and configured to direct the backwash through the filter media and into the filter disc where the backwash dislodges suspended solids from the filter media and a backwash and suspended solids mixture is formed; a plurality of backwash guides secured to or integrally formed with the filter frame and projecting inwardly from the filter frame into the filter disc, the backwash guides projecting inwardly from opposite sides of the filter disc into the interior of the filter disc and including elongated edges that angle inwardly with respect to the filter media; the backwash guides and a portion of the filter disc form a series of backwash channels that extend through the filter disc; wherein the backwash channels extend generally toward the openings in the inner perimeter of the filter disc; and wherein in a backwashing operation, the backwash channels are configured to receive at least a portion of the backwash and suspended solids mixture and to direct the backwash and the suspended solids to the openings in the inner perimeter of the filter disc where the backwash and suspended solids pass through the openings in the drum and into the solids trough.