Novel rare-earth wastewater comprehensive treatment system and method

The invention relates to a novel rare-earth wastewater comprehensive treatment system which comprises a pretreatment unit, a sewage enrichment unit and a supercritical water oxidation unit, wherein the pretreatment unit comprises a screening device, a regulating tank and a floatation tank which are sequentially communicated; an inlet of the sewage enrichment unit is connected with an outlet of the pretreatment unit; a clean water outlet of the sewage enrichment unit is connected with a clean water tank; a supercritical water oxidation reactor, a gas-solid separation system and a gas-liquid separation system of the supercritical water oxidation unit are sequentially connected; a sewage inlet of the supercritical water oxidation reactor is connected with a concentrated water outlet of the sewage enrichment unit; an oxygen inlet of the supercritical water oxidation reactor is connected with the oxygen supply system; and an outlet of the gas-liquid separation system is connected with the clean water tank. The system integrates multiple processes to perform supercritical water oxidation treatment on rare-earth wastewater with wider COD (chemical oxygen demand) range, the organic matter removal rate can reach 99% above, and the chroma reaches the standard. The system has the advantages of thorough sewage treatment and lower cost.