Method for removing COD (Chemical Oxygen Demand) and recycling high-ammonia-nitrogen high-salt organic wastewater

Abstract

The invention provides a method for removing COD (Chemical Oxygen Demand) from high-ammonia-nitrogen high-salt organic wastewater, which comprises the following steps: (1) adding alkali into high-ammonia-nitrogen wastewater for deamination to obtain deaminated liquid; (2) standing the deaminated liquid to separate out sodium sulfate crystal salt, and performing solid-liquid separation to obtain crystallized liquid; (3) adjusting the pH value of the crystallized liquid, and aerating; (4) performing electrocatalytic oxidation on the solution obtained in the step (3); (5) further performing Fenton reaction on the solution obtained in the step (4); (6) adding alkali liquor to adjust the solution obtained in the step (5) to be alkaline; and (7) adding a flocculating agent into the solution obtained in the step (6), and carrying out solid-liquid separation to obtain a COD-removed solution. According to the method, COD in the high-ammonia-nitrogen high-salt organic wastewater can be efficiently removed, meanwhile, ammonium salt and sodium sulfate can be recycled, the treatment cost is low, the slag amount is small, and the treatment steps are simple and convenient.

Description

technical field [0001] The invention relates to the field of wastewater treatment in the new energy industry, in particular to a method for removing COD and recycling organic wastewater with high ammonia nitrogen and high salt. Background technique [0002] In the process of nickel, cobalt, manganese smelting and nickel-cobalt-manganese recovery of waste batteries, P507 or P204 are commonly used for nickel-cobalt enrichment and purification. The extraction method can realize the enrichment and purification of nickel, cobalt and manganese. Generally, the extractant (mainly phosphate ester extractant, such as P507, P204) is diluted with a solvent such as sulfonated kerosene before extraction, and then ammonia water is used. Or saponification such as liquid caustic soda, saponification of the organic phase for extraction. After the extraction reaction finishes, through mechanical clarification, phase separation obtains raffinate (water phase) and extraction phase (cobalt-rich ...

AI Technical Summary

Problems solved by technology

However, the existing methods for high-ammonia-nitrogen and high-salt organic wastewater have great limitations, such as the coagulation-sedimentation method has a low removal rate of dissolved substances, low reuse rate of activated carbon and high cost; the traditional Fenton method is too expensive to treat , a large amount of iron-containing sludge will be produced during the degradation of organic matter, causing secondary pollution. At the same time, due to the presence of a large amount of ammonium sulfate in the solution, a large amount of ammonia gas will also be generated in the Fenton reaction, which will pollute the air. The concentration of salt will reduce the removal efficiency of COD in organic wastewater; because there are a lot of ammonium sulfate and oil in the wastewater, and the electro-oxidation process is non-selective, so the electro-oxidation process not only needs to oxidize organic matter, but also needs to oxidize ammonium ions, so that Lead to high power consumption; high salt water environment is not conducive to the growth of microorganisms, and microbial poisoning will occur, so biochemical methods are not suitable for treating this type of wastewater

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