Method for treating high-nitrogen and low-carbon rare earth ore mining wastewater step by step by using microalgae and activated sludge

Abstract

The invention discloses a method for treating high-nitrogen and low-carbon rare earth ore mining wastewater by using microalgae and activated sludge and belongs to the technical field of sewage treatment. The method for treating rare earth ore mining water comprises the following steps: 1) regulating the ratio of nitrogen and phosphorus in the rare earth ore mining wastewater to (0.5-1.5):(2-3) byusing a phosphorus-containing compound to obtain to-be-purified wastewater; 2) adding enriching microalgae into the to-be-purified wastewater to carry out purification treatment, and separating algaefrom water to obtain primarily-purified water; and 3) adding activated sludge into the primarily-purified water to carry out purification treatment again to obtain purified water. The wastewater is treated by using scenedesmus and chlorella in the method for treating high-nitrogen and low-carbon rare earth ore mining wastewater by using microalgae and activated sludge, so that the contents of ammonia nitrogen and total nitrogen in the wastewater can be effectively reduced, COD additionally added during microalgae treatment is subjected to purification treatment again by the activated sludge,so that the COD value is reduced to 32mg / L, and the wastewater meets a discharge requirement of the first level A of the discharge standard for pollutants from an urban wastewater treatment plant.

Description

technical field [0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a method for step-by-step treatment of high-nitrogen and low-carbon rare earth mining wastewater by using microalgae and activated sludge. Background technique [0002] my country is the country with the largest rare earth reserves in the world. The mining of rare earth mines in Ganzhou, Jiangxi Province is very active. A large amount of ammonium sulfate is used as the extraction solution in the mining process of rare earth mines. Therefore, sulfate ions, ammonium ions , and nitrate ion content are very high, and there is almost no organic matter in the wastewater. For this kind of high-nitrogen wastewater with special components and serious pollution, there is still a lack of good treatment methods. [0003] At present, the available treatment methods for rare earth mining wastewater include the use of air stripping, chemical methods of break point chlorinati...

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Problems solved by technology

[0002] my country is the country with the largest rare earth reserves in the world. The mining of rare earth mines in Ganzhou, Jiangxi Province is very active. A large amount of ammonium sulfate is used as the extraction solution in the mining process of rare earth mines. Therefore, sulfate ions, ammonium ions , and the content of nitrate ions is very high, and there is almost no organic matter in the wastewater. For this kind of high-nitrogen wastewater with special components and serious pollution, there is still a lack of good treatment methods

[0003] At present, the available treatment methods for rare earth mining wastewater include the use of air stripping, chemical methods of break point chlorination and ion exchange, physical methods of membrane filtration and reverse osmosis, and biological methods such as nitrification and denitrification and oxidation ponds, but air stripping and Breakpoint chlorination is only effective for ammonia nitrogen, but not for nitrate nitrogen; ion exchange and nanofiltration reverse osmosis are expensive, and operation and management are complicated; The concentration of sulfate radicals will also adversely affect the physiological activities of activated sludge. Denitrification is under anoxic conditions, so its operation and management are complicated. The microorganisms in the oxidation pond have not been domesticated, so it is difficult to adapt to this special water quality.

Therefore, the method for the mining wastewater of rare earth mines in the prior art has the defects of high cost, poor feasibility, and being unfavorable for large-scale treatment.

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