Composite landfill leachate treatment system

The invention provides a composite landfill leachate treatment system, which comprises a liquid collection tank, a fine filtration tower, an electrolytic tank, a three-dimensional electrode tank, a hydrodynamic cavitation tank and a biological resin tank, wherein the liquid collection tank, the fine filtration tower, the electrolytic tank, the three-dimensional electrode tank, the hydrodynamic cavitation tank and the biological resin tank are sequentially communicated through pipelines, the electrolytic tank is filled with an iron-carbon mixed filler layer, and is provided with a water inlet and a water outlet, the water inlet and the water outlet of the electrolytic tank are respectively positioned on different sides of the iron-carbon mixed filler layer, the three-dimensional electrode tank comprises graphene sponge, an anode and a cathode, the three-dimensional electrode tank is filled with the graphene sponge, the anode and the cathode are inserted into the graphene sponge at a certain distance, the anode