Head water quality pre-purification method for water obtained from lake and reservoir type water source

The present invention relates to the technology of water quality purification treatment, and discloses a head water quality pre-purification method for water obtained from a lake and reservoir type water source. In the method, a step basin type floating island structure with high edges and a low middle is adopted; along the flow direction, a grating, a microbiological flocculation layer, a short fiber filter material layer, a foam iron adsorption layer, a biological activated carbon purification layer, and a three-dimensional coupling electrode reaction layer which are used for filtering and removing sundries are arranged in sequence on each step from outside to inside; raw water passes through the grating, the microbiological flocculation layer, the short fiber filter material layer, the foam iron adsorption layer, the biological activated carbon purification layer, and the three-dimensional coupling electrode reaction layer from the edges via a step basin by relaying on gravity flow, then flows to the cente