Method for treating low-concentration ammonia-containing wastewater by use of membrane separation technology

Abstract

The invention relates to a treatment method for low-concentration ammonia-containing wastewater, and particularly relates to a technical method taking a membrane separation technology as a core treatment unit. Low-concentration ammonia-containing wastewater often occurs in the production process of the chemical industry; although the concentration is relatively low, the low-concentration ammonia-containing wastewater is hard to treat and not easy to recycle. According to the characteristics, the invention provides a method for treating low-concentration ammonia-containing wastewater by use of a membrane separation technology, which specifically comprises the steps of neutralization with sulfuric acid, ultrafiltration separation, nanofiltration concentration and separation and reverse osmosis concentration and separation. The concentrated solution of nanofiltration can be recycled as a concentrated ammonium sulfate solution and is utilized in a production process; the yielding water of reverse osmosis can reach relatively high yielding water quality and can be discharged or recycled; the thick water of reverse osmosis flows back to the incoming water of nanofiltration so that the whole process basically realizes zero discharge and is environmentally friendly and energy-saving.

Description

technical field [0001] The invention relates to a treatment method for low-concentration ammonia-containing wastewater, in particular to a technical method with membrane separation technology as the core treatment unit, and belongs to the technical field of water treatment. Background technique [0002] Most of the ammonia-containing wastewater comes from the process links of large-scale chemical production. Typical industries, such as the production process of persulfate, will produce a large amount of ammonia-containing wastewater. Persulfate, also known as peroxodisulfate, includes lithium, sodium, potassium, rubidium, cesium, ammonium, manganese, calcium, strontium, barium and other persulfates. Among them, three kinds of persulfates of sodium, potassium and ammonium, which are widely used and have formed industrial production scale, are collectively referred to as alkali metal persulfates. Persulfates are mainly used as polymerization initiators for synthetic resins, s...

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Problems solved by technology

[0009] The treatment methods of general traditional ammonia-containing wastewater include evaporation, stripping, biological treatment, etc., but these techniques all have considerable limitations, such as CN99116665. The ammonia-containing wastewater is cooked in the kettle, and the ammonia gas produced by the cooking is absorbed into ammonia water. This method is suitable for general ammonia-containing wastewater with complex components, and can achieve the purpose of recycling ammonia, but its huge energy consumption is the The biggest problem with the method is that it is not suitable for the condensed ammonia-containing wastewater in the persulfate production process; the blow-off process is to use air or steam to take ammonia out in gas form and recycle it. The blow-off method for treating ammonia-containing wastewater is very mature , such as ZL90107237.0 uses single-tower steam stripping to treat refinery ammonia-containing wastewater. This technical means is economically suitable for treating concentrated ammonia-containing wastewater, especially when the water volume is small, while the water volume is large and ammonia When the ammonia content is low, this treatment method will consume a lot of energy, and the economy is poor, so it is not suitable for application; for low-concentration ammonia-containing wastewater, traditional biological treatment methods can also be used, but because the treated water quality becomes complicated, it cannot Realize the recycling of ammonia components, causing unnecessary waste

[0010] In summary, the traditional technical methods have certain disadvantages, such as large energy consumption, poor economy, or failure to achieve the purpose of resource recovery. Therefore, the present invention proposes a membrane concentration recovery method for treating ammonia-containing wastewater. To overcome the defects existing in the prior art

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