Ammonia nitrogen is the main nutrient of plants and microorganisms, and the concentration of ammonia nitrogen in water is an important index to evaluate the pollution degree of water. The increase of ammonia nitrogen content in water will cause eutrophication of the water body, make water black and smelly, and cause water quality deterioration. For the sustainable development of ecology, the discharge standard of ammonia nitrogen wastewater is increasingly strict.
Non-ferrous metal smelting wastewater mainly comes from the use of liquid ammonia and ammonia water as metal precipitators (such as tantalum and niobium), extractants (such as tungsten smelting) to produce a large number of precipitating mother liquor and washing water, or extract residue wastewater. A large amount of ammonia nitrogen industrial wastewater produced in the process of non-ferrous metal metallurgy cannot be discharged directly, and it is one of the special wastewater that is difficult to be treated by non-ferrous metallurgical enterprises. It can be discharged only after the treatment of ammonia nitrogen removal and reducing the ammonia nitrogen concentration of wastewater.
Common ammonia nitrogen wastewater treatment technologies include the biological process, air-stripping method, membrane technology, adsorption method, stripping distillation, etc.
The biological process established the biological nitrogen removal system, which can realize effective nitrogen removal of high-salt wastewater. This process has low production cost, short cycle, and high nitrification and denitrification efficiency. However, it is only suitable for nitrogen removal treatment of wastewater with low ammonia concentration. For wastewater with high ammonia concentration, a large amount of water will be needed to dilute it in advance, resulting in large wastewater output, higher cost, and poor applicability. The air-stripping method is mostly used in the pretreatment stage of wastewater with high ammonia nitrogen concentration. The residual concentration of ammonia nitrogen in the wastewater after adding chemical agents for reaction by the chemical adsorption method is high, and corresponding measures should be taken to deal with it. The ammonia-containing wastewater obtained by stripping ammonia cannot be discharged directly up to the standard and needs further biochemical treatment, which has certain limitations. The nitrogen removal effect of ammonia nitrogen wastewater with low concentration is not good. A large number of alkaline reagents will be needed if the nitrogen should be removed sufficiently, which requires high reaction conditions and has the disadvantages of high energy consumption and easy secondary pollution at the same time.
The degassing membrane uses the principle of diffusion, and degassing purpose can be achieved by using the hydrophobicity and air permeability of the hollow fiber membrane; that is, under certain conditions, gas can pass through the membrane surface while liquid cannot. Due to the large surface area of the hollow fiber membrane, the water and the membrane can be fully contacted to achieve a good degassing effect, and the degassing efficiency can reach 99.99%.
Ammonia removal by degassing membrane method has the advantages of high removal efficiency, simple and convenient operation, small footprint, stable operation, and flexible expansion, thus realizing the goal of wastewater harmlessness and resourcezation treatment, and helping non-ferrous metal and other related metallurgical enterprises to solve the problem of wastewater discharge fundamentally.
Since the establishment of Guochu Technology (Xiamen) Co., Ltd, we have taken membrane separation technology as our core and are committed to the promotion of new separation technology. We have provided comprehensive filtration and purification solutions to biopharmaceutical, food and beverage, fermentation, agricultural products deep processing, plant extraction, petroleum and petrochemical, environmental protection water treatment, gas separation, chemical industry, and other industries to meet the highly differentiated needs of different customers.
Guochu Technology (Xiamen) Co., Ltd. will also continue to explore new applications of the new degassing membrane technology in the fields of food, dairy, beverage, microelectronics, metallurgy, chemical industry, machinery, and environment to provide more users with professional gas separation solutions.
