The invention provides a high-efficiency oily
sewage treatment method, comprising the following steps: pressurizing to-be-treated oily
sewage, and then delivering the pressurized oily
sewage into an electric
flocculation tank so as to generate a polynuclear hydroxy complex,
hydroxide floccules and
hydrogen gas bubbles; adding gas-dissolved water into the oily sewage after
electrolysis to enable the polynuclear hydroxy complex to adsorb the floccules,
sediment grains and large-particle oil drops in the sewage; wrapping the oil drops and the
sediment grains with micro-bubbles and
hydrogen gas bubbles in the gas-dissolved water; performing
cyclone separation to remove the floccules, the large
sediment grains and the oil drops; and performing flotation separation on the treated sewage in a full-water low-pressure state to remove the remaining polynuclear hydroxy complex-oil drops,
hydroxide floccules-
suspended particles, micro-bubbles-oil drops and sediment impurities, so as to obtain
purified water. The device and the method provided by the invention can be used for removing oil drops, sediments, colloids, dissolved organic matters and heavy
metal ions in sewage at the same time,
bacteria and viruses in water can also be killed without adding chemical reagents, and the
water quality after treatment is stable and reaches the standards.