Method for treating high-concentration nitrate wastewater

Abstract

The invention discloses a method for treating high-concentration nitrate wastewater. The method includes the following steps: S1, adding a carbon source and nitrogen and phosphorus nutrients into thenitrate wastewater, and adjusting the pH of the wastewater to 2-4 to obtain pretreated wastewater; and S2, mixing the pretreated wastewater and circulating water, introducing the obtained mixed waterinto an anoxic expanded bed reactor to be in contact with a biological filler, and performing a denitrification reaction to obtain denitrified wastewater, wherein the circulating water is a product obtained by the denitrification reaction of the pretreated wastewater and the biological filler. The cost of treating the nitrate wastewater by using the method is lower, and the method can continuouslytreat the high-concentration nitrate (3000-35000 mg / L) wastewater, and has high treatment efficiency.

Description

technical field [0001] The invention relates to a method for treating high-concentration nitrate wastewater. Background technique [0002] Nitrogen and phosphorus are one of the main factors causing water eutrophication, especially the increasing discharge of nitrate in industrial sewage, which seriously damages the natural cycle of nitrogen. Nitrates can be reduced to nitrites, which cause methemoglobinemia. When the normal hemoglobin content in the human body is lower than 90%, it will cause suffocation or even death. In order to maintain the ecological environment and protect people's health, the country's sewage discharge standards are gradually stricter. For example, the effluent standards of the United States, Canada and other countries TN (total nitrogen content) is less than 3mg / L and TP (total phosphorus content) is less than 0.18mg / L, so It is urgent to deal with the problem of nitrate in wastewater. [0003] Different methods can be used to treat high-concentra...

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Problems solved by technology

It has been reported that using graphite electrode electrosorption to treat potassium nitrate-containing brine, the removal rate of nitrate nitrogen can reach 52.2%, but the disadvantage of this method is high cost and poor ability to remove nitrate

CN 103964550A discloses a method of using graphene-loaded nano-iron to adsorb and remove nitrate in water, and the removal rate of nitrate nitrogen can reach 85%, but the preparation of graphene-loaded nano-iron needs to be carried out under the protection of an inert atmosphere or a nitrogen atmosphere. The operation is complex and cannot handle large-scale wastewater, and this process is difficult for practical application

Another method is to use new technology of ion exchange to treat nitrate wastewater, and use D890 resin to completely remove nitrate in wastewater. However, due to the large amount of nitrate wastewater in industrial production, and D890 resin is expensive, the cost of treating a large amount of wastewater is too high. High, difficult to meet the needs of actual production

CN106219716A discloses a method for treating high-concentration nitrate wastewater. Under normal temperature and pressure, zinc powder and sulfamic acid are added to high-concentration nitrate wastewater to react. The method does not need to purchase additional wastewater treatment equipment. After wastewater treatment, NO 3 - Concentration ≤ 15mg / L, but the disadvantage is the introduction of secondary pollution such as zinc powder

[0004] The biological denitrification process has attracted extensive attention due to its low treatment cost. The denitrifying bacteria use the self-existing carbon source or external carbon source in the wastewater as an electron donor to convert nitrate into nitrogen for removal. The activity of denitrifying bacteria is usually inhibited under nitrate conditions

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