Ammonia nitrogen removal and ammonium salt enrichment method for high-concentration ammonia-nitrogen wastewater through membrane method

Abstract

The invention discloses an ammonia nitrogen removal and ammonium salt enrichment method for high-concentration ammonia-nitrogen wastewater through a membrane method. The ammonia nitrogen removal and ammonium salt enrichment method comprises the steps that firstly, impurity removal through sedimentation is conducted to obtain purified high-concentration ammonia-nitrogen wastewater; secondly, the pH of the wastewater is regulated to be 10-11 by adding alkali to enable ammonia nitrogen to exist in the form of volatile NH3; finally, ammonia nitrogen in the wastewater is removed through the gas membrane process, the operation conditions are strictly controlled, the osmotic distillation process of water which has the same mass transfer direction as ammonia and is accompanied in the gas membrane process is effectively inhibited, the condition that an absorption solution is diluted is avoided, a high-concentration ammonium salt solution is obtained, and the step of concentration of the diluted absorption solution is omitted. According to the method, efficient and low-consumption ammonia removal of the high-concentration ammonia nitrogen wastewater can be achieved, no secondary pollution is generated, and environmental friendliness is achieved.

Description

technical field [0001] The invention relates to wastewater treatment technology, in particular to a membrane method high-concentration ammonia nitrogen wastewater treatment technology. Background technique [0002] With the development of industrial and agricultural production and the improvement of people's living standards, the discharge of nitrogen-containing compounds has increased sharply, and has become the main source of environmental pollution and has attracted attention from all walks of life. Ammonia-nitrogen wastewater has a wide range of sources and a large amount of discharge, such as chemical fertilizers, petrochemicals, metallurgy, pharmaceuticals, food, landfills, etc., all produce a large amount of high-concentration ammonia-nitrogen wastewater. When the concentration of ammonia nitrogen is high, it is easy to cause eutrophication of the water body. In severe cases, the dissolved oxygen in the water will drop sharply, a large number of fish will die, the bal...

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Problems solved by technology

However, in the gaseous membrane deamination process, not only ammonia molecules enter the absorption liquid through the membrane wall, but also water molecules enter the absorption liquid through the micropores on the membrane wall, resulting in rapid expansion of the absorption liquid volume, a decrease in the concentration of the absorption liquid, and a decrease in the absorption capacity. decline, the operation cannot be carried out smoothly, which seriously hinders the industrial application process of the method

The current solution is to stop the operation and concentrate the absorption liquid when the removal rate of ammonia nitrogen is greatly reduced or when the volume of the absorption liquid expands by half, which has the disadvantages of complicated process and high treatment cost.

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