NOVELTY - Small-scale annual composite purification system comprises a buffering pool (1), an aeration tank (201), an anaerobic fermenting tank (202), a water hyacinth culturing tank (301), a small artificial wetland (302), a methane tank and a greenhouse. The aeration tank, anaerobic fermenting tank, water hyacinth culturing tank, small artificial wetland and methane tank are mounted in the greenhouse. A heat supply network is mounted below the greenhouse. The sewage is drained in the river system through e.g. buffering pool, aeration tank, anaerobic fermenting tank, and water hyacinth culturing tank.    USE - The small-scale annual composite purification system is useful for purifying domestic sewage through water hyacinth.    ADVANTAGE - The system can purify municipal sewage, recycle nutritional source and perform resource utilization for the wetland plant; and can achieve high efficiency operation.    DETAILED DESCRIPTION - Small annual composite purification system comprises a buffering pool (1), an aeration tank (201), an anaerobic fermenting tank (202), a water hyacinth culturing tank (301), a small artificial wetland (302), a methane tank and a greenhouse. The aeration tank, the anaerobic fermenting tank, the water hyacinth culturing tank, the small artificial wetland and methane tank are mounted in the greenhouse. A heat supply network is mounted below the greenhouse. The sewage is drained in the river system through the buffering pool, aeration tank, anaerobic fermenting tank, water hyacinth culturing tank and small artificial wetland. The plants of water hyacinth culturing tank and small artificial wetland are conveyed to the methane tank. The biogas slurry in methane tank is fed to the phosphorus recycling module. The methane in the methane tank is fed to a hot water boiler. The hot water boiled by hot water boiler is fed to the heat supply pipe network. The heat produced by the heat supply pipe network is fed to the greenhouse.    DESCRIPTION OF DRAWING(S) - The drawing shows a block diagram of the small-scale annual composite purification system.    Buffering pool (1)    Aeration tank (201)    Anaerobic fermenting tank (202)    Water hyacinth culturing tank (301)    Small artificial wetland (302)