Food industry sewage treatment system and method

The invention discloses a food industry sewage treatment system. The food industry sewage treatment system comprises a water collecting well, a hydraulic screen, a preliminary sedimentation tank, a regulating tank, a UASB (upflow anaerobic sludge blanket) reactor, a CASS (cyclic activated sludge system) reactor, a sand filter tank and a quicksand filter, wherein food industry sewage of the water collecting well enters the hydraulic screen through a lifting pump; the hydraulic screen, preliminary sedimentation tank, regulating tank, UASB reactor, CASS reactor, sand filter tank and quicksand filter are sequentially communicated through a pipeline; the regulating tank is communicated with the CASS reactor through a pipeline; the UASB reactor is provided with a biogas recycling system; and the food industry sewage treatment system also comprises a cooling tower for cooling food industry sewage in the regulating tank. The invention also discloses a food industry sewage treatment method. The food industry sewage treatment system disclosed by the invention can implement complete equipment control on the food industry sewage from the water inlet stage to the water outlet stage, has wider applicability, and is convenient for operation and maintenance.