CN111847701A - Pretreatment method of ultrahigh-concentration ammonia nitrogen wastewater - Google Patents
Pretreatment method of ultrahigh-concentration ammonia nitrogen wastewater Download PDFInfo
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Abstract
The invention discloses a pretreatment method of ultra-high concentration ammonia nitrogen wastewater, which mainly comprises the following steps: (1) adding a solution containing sulfite ions into the ammonia nitrogen wastewater with ultrahigh concentration, and uniformly mixing to obtain a mixed solution; (2) adjusting the mixed solution to be acidic; (3) and (3) adding the solution containing ferrous ions or ferric ions into the mixed solution adjusted to be acidic in the step (2), stirring for reaction, separating, and removing precipitates to obtain the low-concentration ammonia nitrogen wastewater. The method for pretreating the ultrahigh-concentration ammonia-nitrogen wastewater by adopting crystallization precipitation is simple, the process route is safe and reasonable, the used raw materials are easily purchased in the market, the product cost is low, secondary pollution is avoided, and the prepared ammonium ferrous sulfite and ammonium ferric sulfite have the advantages of high purity, high economic benefit and the like.
Description
Technical Field
The invention relates to a wastewater pretreatment method, in particular to a pretreatment method of ultra-high concentration ammonia nitrogen wastewater, belonging to the technical field of wastewater treatment in resource environment protection.
Background
The ammonia nitrogen wastewater mainly comes from fertilizers, coking, petrifaction, pharmacy, foods, refuse landfills and the like. After entering the water body, a large amount of ammonia nitrogen wastewater can become nutrient elements of organisms such as algae, so that toxic organisms in the water body are massively propagated in a short time, and eutrophication phenomena such as red tide and water bloom are generated, and meanwhile, dissolved oxygen in water can be consumed, and the life safety of fishes and shrimps and the health of people and livestock are seriously threatened.
At present, with the rapid development and growth of industries such as chemical fertilizers, petrochemical industry and the like, the generated high ammonia nitrogen wastewater also becomes one of the industry development restriction factors; according to the report, red tide occurs up to 77 times in 2001 in China's sea area, ammonia nitrogen is one of important causes of pollution, in particular to pollution caused by high-concentration ammonia nitrogen wastewater. Therefore, the economic and effective control of high concentration pollution is also an important subject of current research by environmental protection workers, and is highly regarded by the industry. The general formation of ammonia nitrogen wastewater is caused by the coexistence of ammonia water and inorganic ammonia, generally, the main source of ammonia nitrogen in wastewater with pH above neutral is the combined action of inorganic ammonia and ammonia water, and the ammonia nitrogen in wastewater under the acidic condition of pH is mainly caused by inorganic ammonia. The ammonia nitrogen in the wastewater mainly comprises two ammonia nitrogen components, wherein one is formed by ammonia water, and the other is formed by inorganic ammonia, and the other is mainly ammonium sulfate, ammonium chloride and the like.
At the present stage, the methods for removing ammonia nitrogen in wastewater commonly comprise a chemical precipitation method, a stripping method, a chemical oxidation method, a biological method, a membrane separation method, an ion exchange method and the like, and each method has advantages and disadvantages. Generally, the precipitation method is applied more in the pretreatment method of high-concentration ammonia nitrogen substances. For the ammonia nitrogen precipitation method, there are reports of struvite precipitation method, such as chinese patent CN 108191115A. However, the method has the problems that the waste water needs to be adjusted to be alkalescent, ammonia gas is released, and secondary pollution is caused in the using process. Also has the disadvantages of high treatment cost and easy residue of magnesium and phosphorus.
Research and analysis find that the method in the prior art is well applied to conventional high-concentration ammonia nitrogen wastewater, such as Chinese patent CN 107473519A. But no good technology exists at present for the ultra-high concentration ammonia nitrogen wastewater (ammonia nitrogen is more than 3000 mg/L). Therefore, if the treatment method can be used for pretreating the ultra-high concentration ammonia nitrogen wastewater to reduce the ammonia nitrogen concentration, and then the conventional high concentration ammonia nitrogen wastewater treatment technology is adopted, the problem of treatment of the ultra-high concentration ammonia nitrogen wastewater can be well solved.
Ammonia nitrogen is one of the important research objects for wastewater treatment, and people are continuously trying to develop and apply various process technologies such as physics, chemistry, biology and the like. In view of the problems of various methods and development prospects thereof, the company continuously reforms, innovatively and develops a pretreatment method for the ammonia nitrogen wastewater with ultrahigh concentration, and tries to strengthen technical innovation in the field of treatment processes for the ammonia nitrogen wastewater with ultrahigh concentration.
Disclosure of Invention
The invention aims to provide a method for pretreating ultrahigh-concentration ammonia nitrogen wastewater by crystallization and precipitation to reduce ammonia nitrogen in the wastewater so that the wastewater can be suitable for the conventional high-concentration ammonia nitrogen treatment method at present, aiming at overcoming the defects of the prior art.
In order to achieve the purpose, the technical scheme provided by the invention is as follows:
a pretreatment method of ultra-high concentration ammonia nitrogen wastewater comprises the following steps:
(1) adding a solution containing sulfite ions into the ammonia nitrogen wastewater with ultrahigh concentration, and uniformly mixing to obtain a mixed solution;
(2) adjusting the mixed solution to be acidic;
(3) and (3) adding the solution containing ferrous ions or ferric ions into the mixed solution adjusted to be acidic in the step (2), stirring for reaction, separating, and removing precipitates to obtain the low-concentration ammonia nitrogen wastewater.
Preferably, the ultra-high concentration ammonia nitrogen wastewater is wastewater containing ammonium ions. Preferably, the concentration of ammonium ions contained in the ultra-high concentration ammonia nitrogen wastewater is not less than 3000mg/L, preferably not less than 3200mg/L, and more preferably not less than 3600 mg/L.
Preferably, the solution containing sulfite ions in the step (1) is a solution containing soluble salts of sulfite ions, preferably one or more of sodium sulfite, sodium bisulfite and potassium sulfite.
Preferably, the adjusting the mixed solution to be acidic in the step (2) is specifically: the pH value of the mixed solution is adjusted to be in a range of 3-7, preferably in a range of 3.5-6.5, and more preferably in a range of 5-6.
Preferably, the solution containing ferrous ions in the step (3) is a solution containing soluble salts of ferrous ions, preferably ferrous chloride and/or ferrous sulfate.
Preferably, the solution containing ferric ions is a solution containing soluble salts of ferric ions, preferably ferric chloride and/or ferric sulfate.
Preferably, the concentration of sulfite ions in the sulfite ion-containing solution in step (1) is more than 0.1mol/L, preferably more than 0.2mol/L, and more preferably more than 0.3 mol/L.
Preferably, the sulfite ion-containing solution is added in an amount such that the molar ratio of sulfite ions to ammonium ions is from 1:0.2 to 2, preferably from 1:0.5 to 1.5, more preferably from 1:0.8 to 1.2.
Preferably, the adjusting of the mixed solution to acidity in step (2) is performed with a dilute acid and/or a dilute base. Preferably, the dilute acid is one or more of sulfuric acid and hydrochloric acid, and the dilute alkali is one or more of sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate and potassium bicarbonate.
Preferably, the mass concentration of the dilute acid is 2-20%, preferably 5-15%, more preferably 8-12%. The mass concentration of the dilute alkali is 2-20%, preferably 5-15%, and more preferably 8-12%.
Preferably, the ferrous ion or ferric ion concentration in the ferrous ion or ferric ion containing solution in step (3) is more than 0.05mol/L, preferably more than 0.1mol/L, more preferably more than 0.2 mol/L; and/or
The amount of the solution containing ferrous ions or ferric ions is added so that the molar ratio of ferrous ions or ferric ions to ammonium ions is 1:0.1 to 1.5, preferably 1:0.2 to 1.2, more preferably 1:0.5 to 1.
Preferably, the stirring reaction time in the step (3) is 0.1-48h, preferably 0.2-24h, more preferably 0.3-12 h; stirring, reacting, cooling and separating. Preferably, the mixed solution after the reaction is cooled to 5-30 ℃, preferably the mixed solution is cooled to 8-25 ℃, and more preferably the mixed solution is cooled to 10-20 ℃; and/or
The separation adopts filtration separation or suction filtration separation, and preferably adopts one or more methods of a gravity precipitation method, an air floatation method or a filtration method to realize solid-liquid separation.
Preferably, the concentration of ammonium ions in the low-concentration ammonia nitrogen wastewater obtained in the step (3) is less than 1800mg/L, preferably less than 1600mg/L, and more preferably less than 1500 mg/L.
In the invention, the purpose of fully and uniformly mixing the ultra-high concentration ammonia nitrogen wastewater and the mixed solution containing sulfite ions and then adjusting the mixture to be acidic is to prevent the ammonium ions in the ammonia nitrogen wastewater from being converted into ammonia gas to cause environmental pollution and waste, and further to prevent the ferrous ions or ferric ions added in the step (2) from being combined with free hydroxide ions to generate precipitates. However, since sulfite ions have very strong reducibility and are oxidized into sulfate ions in a strong acid environment, the adjustment of the ultra-high concentration ammonia nitrogen wastewater and the mixed solution containing sulfite ions to acidity in the invention means adjustment to weak acidity (for example, pH value of 3 to 7, preferably pH value of 3.5 to 6.5, more preferably pH value of 5 to 6).
The concentration of sulfite ions in the solution containing sulfite ions added in the step (1) is more than 0.1mol/L, and the concentration of ferrous ions or ferric ions in the solution containing ferrous ions or ferric ions added in the step (3) is more than 0.05mol/L, so that the concentration of ammonium ferrous sulfite or ammonium ferric sulfite formed in the solution is more than the crystallization precipitation concentration of the ammonium ferrous sulfite or ammonium ferric sulfite, because the ammonium ferrous sulfite and the ammonium ferric sulfite do not belong to precipitates, the crystals of the ammonium ferrous sulfite and the ammonium ferric sulfite are mainly supersaturated crystals. In the step (3), after stirring reaction, cooling to 5-30 ℃ for example is carried out to destroy the metastable zone of the ammonium ferrous sulfite and the supersaturated solution of the ammonium ferrous sulfite so as to separate out crystals. Since studies have shown that the solubility of ferrous ammonium sulfite and ferric ammonium sulfite solutions increases with increasing temperature.
The invention utilizes ferrous ammonium sulfite (NH)4)2Fe(SO3)2Or ferric ammonium sulfite NH4Fe(SO3)2Low solubility, adding SO to the wastewater3 2-Solution and Fe2+(or Fe)3+) And the solution realizes the removal of ammonia nitrogen. Adding sulfite ions and ferrous ions or ferric ions into ammonium ions in the high-concentration ammonia nitrogen wastewater, and utilizing soluble SO3 2-、NH4 +、Fe2+A composite reaction occurs to form ferrous ammonium sulfite (NH)4)2Fe(SO3)2. Due to ferrous ammonium sulfite (NH) 4)2Fe(SO3)2The solubility of the compound is low, and the compound can be separated out from the solution preferentially to form a precipitate; or by readily soluble 5O3 2-、NH4 +、Fe3+A composite reaction occurs to form ferric ammonium sulfite NH4Fe(SO3)2. Due to ammonium ferric sulfite NH4Fe(SO3)2The solubility of (b) is low, and precipitates are preferentially formed from the solution, thereby forming a precipitate.
The chemical formula of the reaction of the invention is as follows:
SO3 2-+NH4 ++Fe2+→(NH4)2Fe(SO3)2↓
SO3 2-+NH4 ++Fe3+→NH4Fe(SO3)2↓。
the ferrous ammonium sulfite prepared by the method has a special sheet shape and high purity, is closer to ferrous ammonium sulfate in terms of chemical composition, and has stronger reducibility than ferrous ammonium sulfate, so that the ferrous ammonium sulfite can be used as an alternative substance for replacing ferrous ammonium sulfate.
Compared with the prior art, the technical scheme of the invention has the following beneficial technical effects:
1. the invention adopts soluble SO3 2-、NH4 +、Fe2+Or Fe3+The compound reaction is carried out, the precipitate is generated, the separation is easy, and the ammonium ions in the high-concentration ammonia nitrogen wastewater are removed with higher efficiency;
2. the ferrous ammonium sulfite (NH) prepared by the invention4)2Fe(SO3)2Or ferric ammonium sulfite NH4Fe(SO3)2The purity is high, the product has special appearance, and the economic benefit is high;
3. the preparation method is simple, the process route is safe and reasonable, the used raw materials are easily purchased in the market, the product cost is low, and secondary pollution is avoided.
Drawings
FIG. 1 is a process flow diagram of the present invention;
FIG. 2 is an X-ray diffraction pattern of ammonium ferrous sulfite prepared by the present invention;
FIG. 3 is a scanning electron microscope image of ammonium ferrous sulfite prepared by the present invention;
Detailed Description
The technical solution of the present invention is illustrated below, and the claimed scope of the present invention includes, but is not limited to, the following examples.
Example 1
(1) Adding a solution containing sulfite ions (a soluble salt solution containing sulfite, such as a sodium sulfite solution; the concentration of sulfite ions in the solution containing sulfite ions is more than 0.1 mol/L; the amount of the solution containing sulfite ions is such that the molar ratio of sulfite ions to ammonium ions is 1:0.2-2, such as 1:1) into the ammonia-nitrogen wastewater with ultrahigh concentration (the ammonia-nitrogen wastewater with ultrahigh concentration refers to the concentration of ammonium ions not less than 3000mg/L, for example, the concentration of ammonium ions not less than 3600mg/L), and uniformly mixing to obtain a mixed solution;
(2) adjusting the mixed solution to weak acidity (adjusting the pH value of the mixed solution to 3-7, such as pH value of 5 or 6);
(3) adding a solution containing ferrous ions or ferric ions (a soluble salt solution containing ferrous ions or ferric ions, such as ferrous chloride; the concentration of the ferrous ions or ferric ions in the solution containing ferrous ions or ferric ions is more than 0.05 mol/L; the amount of the solution containing ferrous ions or ferric ions is 1:0.1-1.5, such as 1:1) into the mixed solution adjusted to be acidic in the step (2), stirring for 0.1-48h (such as 24h), cooling the mixed solution to 5-30 ℃ (such as 15 ℃) after reaction, separating, and removing precipitates to obtain the low-concentration ammonia nitrogen wastewater.
Example 2
(1) Adding a sodium sulfite solution with the concentration of sulfite ions of 0.2mol/L into ammonia nitrogen wastewater with the concentration of 3600mg/L of ammonium ions, wherein the adding amount is that the molar ratio of the sulfite ions to the ammonium ions is 1:1, and uniformly mixing to obtain a mixed solution;
(2) adjusting the pH value of the mixed solution to 1;
(3) adding a ferrous chloride solution with ferrous ion concentration of 0.2mol/L into the mixed solution adjusted to be acidic in the step (2), stirring and reacting for 24 hours, cooling the mixed solution after reaction to 15 ℃, and detecting that the content of ammonium ions in the ammonia nitrogen wastewater is 3489mg/L without obvious precipitation.
Example 3
(1) Adding a sodium sulfite solution with the concentration of sulfite ions of 0.2mol/L into ammonia nitrogen wastewater with the concentration of 3600mg/L of ammonium ions, wherein the adding amount is that the molar ratio of the sulfite ions to the ammonium ions is 1:1, and uniformly mixing to obtain a mixed solution;
(2) adjusting the pH value of the mixed solution to 2;
(3) adding a ferrous chloride solution with ferrous ion concentration of 0.2mol/L into the mixed solution adjusted to be acidic in the step (2), stirring and reacting for 24 hours, cooling the mixed solution after the reaction to 15 ℃, forming a small amount of precipitate, separating, removing the precipitate, detecting the content of ammonium ions in the ammonia nitrogen wastewater to be 3011mg/L, and detecting the purity of ferrous ammonium sulfite to be 99%.
Example 4
(1) Adding a sodium sulfite solution with the concentration of sulfite ions of 0.2mol/L into ammonia nitrogen wastewater with the concentration of 3600mg/L of ammonium ions, wherein the adding amount is that the molar ratio of the sulfite ions to the ammonium ions is 1:1, and uniformly mixing to obtain a mixed solution;
(2) adjusting the pH value of the mixed solution to 4;
(3) adding a ferrous chloride solution with ferrous ion concentration of 0.2mol/L into the mixed solution adjusted to be acidic in the step (2), stirring and reacting for 24 hours, cooling the mixed solution after the reaction to 15 ℃, forming a large amount of precipitates, separating, removing the precipitates, detecting that the content of ammonium ions in the ammonia nitrogen wastewater is 1739mg/L, and the purity of ferrous ammonium sulfite is 99%.
Example 5
(1) Adding a sodium sulfite solution with the concentration of sulfite ions of 0.2mol/L into ammonia nitrogen wastewater with the concentration of 3600mg/L of ammonium ions, wherein the adding amount is that the molar ratio of the sulfite ions to the ammonium ions is 1:1, and uniformly mixing to obtain a mixed solution;
(2) adjusting the pH value of the mixed solution to 5;
(3) adding a ferrous chloride solution with ferrous ion concentration of 0.2mol/L into the mixed solution adjusted to be acidic in the step (2), stirring and reacting for 24 hours, cooling the mixed solution after reaction to 15 ℃, forming a large amount of precipitates, separating, removing the precipitates to obtain low-concentration ammonia nitrogen wastewater, and detecting that the content of ammonium ions in the low-concentration ammonia nitrogen wastewater is 1546mg/L and the purity of ferrous ammonium sulfite is 99%.
Example 6
(1) Adding a sodium sulfite solution with the concentration of sulfite ions of 0.2mol/L into ammonia nitrogen wastewater with the concentration of 3600mg/L of ammonium ions, wherein the adding amount is that the molar ratio of the sulfite ions to the ammonium ions is 1:1, and uniformly mixing to obtain a mixed solution;
(2) adjusting the pH value of the mixed solution to 6;
(3) adding a ferrous chloride solution with ferrous ion concentration of 0.2mol/L into the mixed solution adjusted to be acidic in the step (2), stirring and reacting for 24 hours, cooling the mixed solution after reaction to 15 ℃, forming a large amount of precipitates, separating, removing the precipitates to obtain low-concentration ammonia nitrogen wastewater, detecting that the content of ammonium ions in the low-concentration ammonia nitrogen wastewater is 1489mg/L, and the purity of ferrous ammonium sulfite is 99%.
Example 7
(1) Adding a sodium sulfite solution with the concentration of sulfite ions of 0.2mol/L into ammonia nitrogen wastewater with the concentration of 3600mg/L of ammonium ions, wherein the adding amount is that the molar ratio of the sulfite ions to the ammonium ions is 1:1, and uniformly mixing to obtain a mixed solution;
(2) adjusting the pH value of the mixed solution to 8;
(3) adding a ferrous chloride solution with ferrous ion concentration of 0.2mol/L into the mixed solution adjusted to be acidic in the step (2), stirring and reacting for 24 hours, cooling the mixed solution after reaction to 15 ℃, forming a large amount of precipitates, separating, removing the precipitates to obtain low-concentration ammonia nitrogen wastewater, and detecting that the content of ammonium ions in the low-concentration ammonia nitrogen wastewater is 1872mg/L and the purity of ferrous ammonium sulfite is 81%.
Example 8
(1) Adding a sodium sulfite solution with the concentration of sulfite ions of 0.2mol/L into ammonia nitrogen wastewater with the concentration of 3600mg/L of ammonium ions, wherein the adding amount is that the molar ratio of the sulfite ions to the ammonium ions is 1:1, and uniformly mixing to obtain a mixed solution;
(2) adjusting the pH value of the mixed solution to 9;
(3) adding a ferrous chloride solution with ferrous ion concentration of 0.2mol/L into the mixed solution adjusted to be acidic in the step (2), stirring and reacting for 24 hours, cooling the mixed solution after reaction to 15 ℃, forming a large amount of precipitates, separating, removing the precipitates to obtain low-concentration ammonia nitrogen wastewater, and detecting that the content of ammonium ions in the low-concentration ammonia nitrogen wastewater is 1668mg/L and the purity of ferrous ammonium sulfite is 70%.
In view of the above embodiment, the treated wastewater and ferrous ammonium sulfite are detected, and the concentration of ammonium ions in the treated wastewater and the purity of the obtained by-product ferrous ammonium sulfite are detected, and the results are as follows:
test detection analysis results
Example 9
(1) Adding a sodium sulfate solution containing sulfate ions into ammonia nitrogen wastewater containing 3600mg/L of ammonium ions, wherein the adding amount is such that the molar ratio of the sulfate ions to the ammonium ions is 1:1, and uniformly mixing to obtain a mixed solution;
(2) Adjusting the pH value of the mixed solution;
(3) adding an iron chloride solution with the iron ion concentration of 0.2mol/L into the mixed solution adjusted to be acidic in the step (2), stirring and reacting for 24 hours, cooling the mixed solution after the reaction to 15 ℃, observing the formation condition of a precipitate, separating, removing the precipitate to obtain treated wastewater, detecting the content of ammonium ions in the treated ammonia nitrogen wastewater, and detecting the purity of the obtained by-product ammonium sulfite.
The procedure of example 9 was followed to test the treatment conditions under different experimental conditions, with the following process conditions and experimental results:
in the invention, the condition that the mixed solution of the ultra-high concentration ammonia nitrogen wastewater and the sulfite ions is adjusted to be acidic refers to the condition that the mixed solution is adjusted to be weakly acidic (for example, the pH value is 3-7, preferably the pH value is 3.5-6.5, and more preferably the pH value is 5-6). Using readily soluble SO3 2-、NH4 +、Fe2+A composite reaction occurs to form ferrous ammonium sulfite (NH)4)2Fe(SO3)2. Due to sulfurous acidIron ammonium (NH)4)2Fe(SO3)2The solubility of the compound is low, and the compound can be separated out from the solution preferentially to form a precipitate; or by readily soluble SO3 2-、NH4 +、Fe3+A composite reaction occurs to form ferric ammonium sulfite NH4Fe(SO3)2. Due to ammonium ferric sulfite NH4Fe(SO3)2The solubility of (b) is low, and precipitates are preferentially formed from the solution, thereby forming a precipitate.
The invention utilizes ferrous ammonium sulfite (NH) 4)2Fe(SO3)2Or ferric ammonium sulfite NH4Fe(SO3)2Low solubility, adding SO to the wastewater3 2-Solution and Fe2+(or Fe)3+) And the solution realizes the removal of ammonia nitrogen.
In the invention, because sulfite ions are required to be added, if the reaction environment is strong acid, the existence of the sulfite ions is destroyed, so that the sulfite ions are decomposed to release sulfur dioxide or are converted into sulfate ions by strong oxidizing acid, and the solubility of ferrous ammonium sulfate or ferric ammonium sulfate is high, so that the ammonium ions in the wastewater or waste liquid cannot be removed by forming precipitates. As shown in the results of examples 2, 3, 10 and 11, in a strong acid environment, sulfite ions are destroyed and converted into sulfate ions, only a small amount of ammonium ferrous sulfite or ammonium ferric sulfite precipitates are formed, and a large amount of ammonium ferrous sulfate or ammonium ferric sulfate is formed, and the solubility of ammonium ferrous sulfate or ammonium ferric sulfate in water is high; the concentration of ammonium ions in the treated wastewater is still high. The solubility of the ammonium ferric sulfate is higher than that of the ammonium ferrous sulfate, so that the concentration of ammonium ions in the treated wastewater is higher under a strong acid condition by adopting the technical scheme of adding the ferric ions than the technical scheme of adding the ferrous ions.
In the invention, if the reaction environment is alkaline, ammonium ions in the ammonia nitrogen wastewater directly react with hydroxide ions in the alkaline environment to generate ammonia gas which escapes to cause secondary pollution. Furthermore, as shown in the results of examples 7, 9, 15 and 16, if an alkaline environment is used, the purity of the finally obtained ferrous or ferric ammonium sulfite is lowered, reducing the economic value of the by-product ferrous ammonium sulfite.
Claims (10)
1. A pretreatment method of ultra-high concentration ammonia nitrogen wastewater comprises the following steps:
(1) adding a solution containing sulfite ions into the ammonia nitrogen wastewater with ultrahigh concentration, and uniformly mixing to obtain a mixed solution;
(2) adjusting the mixed solution to be acidic;
(3) and (3) adding the solution containing ferrous ions or ferric ions into the mixed solution adjusted to be acidic in the step (2), stirring for reaction, separating, and removing precipitates to obtain the low-concentration ammonia nitrogen wastewater.
2. The pretreatment method of the ultra-high concentration ammonia nitrogen wastewater according to claim 1, characterized in that: the ultra-high concentration ammonia nitrogen wastewater is wastewater containing ammonium ions; preferably, the concentration of ammonium ions contained in the ultra-high concentration ammonia nitrogen wastewater is not less than 3000mg/L, preferably not less than 3200mg/L, and more preferably not less than 3600 mg/L.
3. The method for pretreating ultra-high concentration ammonia nitrogen wastewater according to claim 1 or 2, characterized by comprising the following steps: the solution containing sulfite ions in the step (1) is a solution of soluble salt containing sulfite ions, preferably one or more of sodium sulfite, sodium bisulfite and potassium sulfite.
4. The method for pretreating ultra-high concentration ammonia nitrogen wastewater according to any one of claims 1-3, wherein the method comprises the following steps: the step (2) of adjusting the mixed solution to acidity specifically comprises: the pH value of the mixed solution is adjusted to be in a range of 3-7, preferably in a range of 3.5-6.5, and more preferably in a range of 5-6.
5. The method for pretreating ultra-high concentration ammonia nitrogen wastewater according to any one of claims 1-4, wherein the method comprises the following steps: the solution containing ferrous ions in the step (3) is a solution of soluble salt containing ferrous ions, preferably ferrous chloride and/or ferrous sulfate; and/or
The solution containing ferric ions is a solution containing soluble salts of ferric ions, and ferric chloride and/or ferric sulfate are preferred.
6. The method for pretreating ultra-high concentration ammonia nitrogen wastewater according to any one of claims 1-5, wherein the method comprises the following steps: the concentration of sulfite ions in the solution containing sulfite ions in the step (1) is more than 0.1mol/L, preferably more than 0.2mol/L, and more preferably more than 0.3 mol/L; and/or
The sulfite ion-containing solution is added in an amount such that the molar ratio of sulfite ions to ammonium ions is from 1:0.2 to 2, preferably from 1:0.5 to 1.5, more preferably from 1:0.8 to 1.2.
7. The method for pretreating ultra-high concentration ammonia nitrogen wastewater according to any one of claims 1-6, wherein the method comprises the following steps: adjusting the mixed solution to be acidic in the step (2) by adopting dilute acid and/or dilute alkali; preferably, the dilute acid is one or more of sulfuric acid and hydrochloric acid, and the dilute alkali is one or more of sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate and potassium bicarbonate;
preferably, the mass concentration of the dilute acid and the dilute alkali is 2-20%, preferably 5-15%, and more preferably 8-12%.
8. The method for pretreating ultra-high concentration ammonia nitrogen wastewater according to any one of claims 1-7, wherein the method comprises the following steps: the concentration of ferrous ions or ferric ions in the solution containing ferrous ions or ferric ions in the step (3) is more than 0.05mol/L, preferably more than 0.1mol/L, and more preferably more than 0.2 mol/L; and/or
The amount of the solution containing ferrous ions or ferric ions is added so that the molar ratio of ferrous ions or ferric ions to ammonium ions is 1:0.1 to 1.5, preferably 1:0.2 to 1.2, more preferably 1:0.5 to 1.
9. The method for pretreating ultra-high concentration ammonia nitrogen wastewater according to any one of claims 1-8, wherein the method comprises the following steps: the stirring reaction time in the step (3) is 0.1-48h, preferably 0.2-24h, and more preferably 0.3-12 h; stirring, reacting, cooling and separating; preferably, the mixed solution after the reaction is cooled to 5-30 ℃, preferably the mixed solution is cooled to 8-25 ℃, and more preferably the mixed solution is cooled to 10-20 ℃; and/or
The separation adopts filtration separation or suction filtration separation, and preferably adopts one or more methods of a gravity precipitation method, an air floatation method or a filtration method to realize solid-liquid separation.
10. The method for pretreating ultra-high concentration ammonia nitrogen wastewater according to any one of claims 1-9, wherein the method comprises the following steps: and (3) the concentration of ammonium ions in the low-concentration ammonia nitrogen wastewater obtained in the step (3) is lower than 1800mg/L, preferably lower than 1600mg/L, and more preferably lower than 1500 mg/L.
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| US3984312A (en) * | 1973-04-23 | 1976-10-05 | Industrial Resources, Inc. | Process for insolubilizing potentially water pollutable wastes from sodium or ammonium type sulfur dioxide air pollution control systems |
| JPS51126990A (en) * | 1975-04-30 | 1976-11-05 | Idemitsu Kosan Co Ltd | Process for removing nitrogen oxides |
| CN102139944A (en) * | 2011-02-21 | 2011-08-03 | 南京大学 | Method for treating high-concentration ammonia nitrogen waste water by utilizing ferric sulfate |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114212930A (en) * | 2021-11-03 | 2022-03-22 | 湘潭大学 | Method for improving purity of wet desulphurization wastewater byproduct |
| CN114212930B (en) * | 2021-11-03 | 2023-05-26 | 湘潭大学 | Method for improving purity of wet desulfurization waste water byproducts |
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