An improved collection system for a wet drum magnetic separator including a tank for receiving a flow of a mixture of magnetic and non-magnetic particles in a feed port. A collection system includes a rotating drum having a roughened collection surface disposed in the tank, an array of permanent magnetic elements disposed inside the drum arranged in a fixed position relative to an azimuthal section of the drum for establishing an azimuthal magnetic interaction region defined by a level of the mixture in the tank for attracting the magnetic particles to the roughened collection surface, a non- magnetic particle discharge port located on an opposite side of the tank that receives the flow for removing the non-magnetic particles, a magnetic particle discharge port located outside the tank for receiving the magnetic particles, and a magnetic particle removal subsystem for removing the magnetic particles trapped in the roughed collection surface and dispensing the magnetic particles to the magnetic particle discharge port.