Coal chemical industry wastewater pretreatment method with combination of hydrolytic acidification and ammonia-nitrogen desorption

Abstract

The invention relates to a coal chemical industry wastewater pretreatment method with the combination of hydrolytic acidification and ammonia-nitrogen desorption. The coal chemical industry wastewater pretreatment method specifically comprises the following steps of 1, first-level ammonia-nitrogen desorption, wherein air is introduced into coal chemical industry wastewater with the high ammonia nitrogen concentration, normal-temperature aeration desorption is performed and stopped till the ammonia nitrogen concentration in the coal chemical industry wastewater is smaller than 300 mg / L; 2, hydrolytic acidification, wherein the coal chemistry wastewater treated after ammonia-nitrogen desorption is subjected to hydrolytic acidification, so that the B / C is improved to 0.3 or more; 3, second-level ammonia-nitrogen desorption, wherein air is introduced into outlet water obtained after hydrolytic acidification again, normal-temperature aeration desorption is performed, and the ammonia-nitrogen concentration generated in wastewater through hydrolytic acidification is decreased, so that the C / N is improved to 4.0-5.0, and the ammonia nitrogen density is smaller than 80-100 mg / L. Compared with the prior art, the coal chemical industry wastewater pretreatment method has the advantages that the wastewater biodegradability can be remarkably improved, the total nitrogen removal rate can reach 60-65%, and the C / N is improved to about 4.0-5.0 so as to reinforce the follow-up biological denitrification effect.

Description

technical field [0001] The invention relates to a wastewater pretreatment method, in particular to a coal chemical wastewater pretreatment method combining hydrolytic acidification and ammonia nitrogen stripping. Background technique [0002] The volume of coal chemical wastewater is as high as several thousand to tens of thousands m 3 / d, the wastewater contains a large amount of solid suspended particles and soluble toxic and harmful compounds, the biodegradability of the wastewater is only about 0.28, there are many kinds of organic pollutants, the chemical composition is very complex, and it contains a large amount of phenols, long-chain alkanes, and aromatic hydrocarbons , Heterocycles, ammonia nitrogen, cyanide and other toxic and harmful substances are typical high-concentration industrial wastewater that is difficult to biodegrade. [0003] The COD value in typical coal chemical wastewater is generally 22000-35000mg / L, the phenol concentration is as high as 4200-750...

AI Technical Summary

Problems solved by technology

[0007] A coal chemical wastewater pretreatment method combining hydrolytic acidification and ammonia nitrogen stripping, aiming at the problem of high organic nitrogen content of complex molecules and low ammonia nitrogen content in coal chemical wastewater with high concentration of total nitrogen, the coal chemical wastewater is passed through the first-stage ammonia nitrogen After stripping and removing ammonia nitrogen in the raw water, the conversion of complex molecular organic nitrogen to ammonia nitrogen is strengthened through the hydrolysis and acidification unit, and then the second-stage ammonia nitrogen stripping is carried out to achieve enhanced pre-removal of total nitrogen and wastewater biodegradability and carbon-nitrogen ratio (C / N) improvement

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