The invention relates to the technical field of sewage treatment equipment, and discloses a secondary sedimentation tank suitable for glass processing wastewater treatment. The sewage treatment tank comprises a tank body, a sludge hopper is arranged at the bottom of the tank body, a sludge outlet pipe is fixedly mounted on one side of the sludge hopper, a central cylinder is fixedly connected to the middle of the sludge hopper, a water inlet pipe is fixedly connected to one side of the bottom of the central cylinder, and a water outlet pipe is fixedly connected to the upper end of the centralcylinder. A mud scraping device is arranged; when the mud scraping device is mounted; a mud scraping plate clings to the tank bottom under the action of an air bag; a gap is prevented from appearing between the mud scraping plate and the tank bottom; incomplete mud scraping is generated, the separation efficiency is influenced, meanwhile, when the sludge scraping plate scrapes sludge, the air baghas a downward compression tendency under the static pressure of water in the tank, and after the sludge scraping plate is abraded, the air bag extrudes the sludge scraping plate, so that the sludgescraping plate is always tightly attached to the bottom of the tank, the situation that a gap exists between the sludge scraping plate and the tank bottom is avoided, and the problems of incomplete sludge scraping and poor sludge scraping effect are avoided.