The invention discloses a sewage treatment system with quick assembly and disassembly functions, and belongs to the technical field of mud scrapers. The system comprises a tank body, a bearing block arranged in the middle of the tank body, a main shaft which is arranged on the bearing block in a rotating manner, and a mud scraper positioned on the main shaft, wherein a connecting rack is fixedly connected on the mud scraper, and a slag scraper is fixedly connected to the upper end of the connecting rack; a supporting rod is fixedly connected on the bearing block, is positioned in the radial direction of the main shaft and is provided with a slag retaining device corresponding to the slag scraper; a support disc is fixedly connected on the main shaft, and mud scraping cylinder rods are fixedly connected to two opposite sides of the support disc; and a supporting rod matched with a mounting hole is arranged in the mounting hole, one end of the supporting rod is fixedly connected with the mud scraper, and the other end of the supporting rod is provided with a spacing hole. According to the sewage treatment system, the problems that the connection structure of the mud scraper of an existing mud scraping machine is fixed and is not beneficial to daily maintenance, and a slag separation device of the mud scraping machine has relatively low scum collection efficiency are solved.