A liquid/solids waste separator apparatus for use in separating animal waste or waste water into filtered liquid and collected solid particles. It has an elongated housing having a pair of support legs attached to the rear end of the housing for varying the inclination angle of the housing. Positioned downwardly from the top edge of the housing is an elongated mesh screen that extends substantially the length of the housing. A plurality of nozzles are laterally spaced from each other and connected to the top of a spray tube that extends transversely beneath the mesh screen. A separate slide pad supports each of the opposite ends of the spray tube and they travel along their respective tracks formed on the inner surface of the respective right and left side walls of the housing beneath the mesh screen. An electric motor drives a chain passing around a pair of longitudinally spaced sprocket gears in the housing. A pin extends upwardly from the chain and it is captured by a travel block that travels transversely in a guide track assembly. This allows the spray tube to reciprocally travel back and forth beneath the mesh screen and the nozzles produces a water knife spray against the bottom surface of the mesh screen to unclog any apertures in the mesh screen that have become clogged. Part of the filtered liquid is recycled by a pump connected to a fluid line leading to the respective nozzles. Waste particles that do not pass through the mesh screen are collected 3in containers placed adjacent the front end of the housing.