CN116589065A - An emergency treatment method for total nitrogen exceeding the standard in nanofiltration concentrated liquid - Google Patents

Abstract

The invention provides an emergency treatment method for total nitrogen exceeding of nanofiltration concentrated solution. The emergency treatment method comprises the following steps: sequentially carrying out Na on nanofiltration concentrated solution ₂ S treatment, secondary Na ₂ S treatment and three times Na ₂ S, processing. The emergency treatment method for the total nitrogen standard exceeding of the nanofiltration concentrated solution provided by the invention explores pH, temperature and acid radical ion Na ₂ The influence of the addition amount of S on the removal effect of total nitrogen in the nanofiltration concentrated solution has the advantages of simple principle, convenient operation, low construction cost investment and higher economic and social environmental benefits.

Description

An emergency treatment method for total nitrogen exceeding the standard in nanofiltration concentrated liquid

technical field

The invention belongs to the field of leachate concentrate treatment with complex components, and relates to an emergency treatment method for the total nitrogen of the nanofiltration concentrate exceeding the standard, in particular to a method for treating high-nitrogen nanofiltration concentrate based on multi-stage nanofiltration.

Background technique

To deal with leachate treatment with complex components and large changes in water quality and quantity with seasons, the traditional biological treatment as the core treatment method is suitable for leachate with low ammonia nitrogen concentration. With the increase of landfill life, the nitrogen content of the leachate system will decrease. Continuously increasing, the removal of total nitrogen has always been a difficult point in the leachate problem. Now the leachate treatment project relies on the "MBR+RO" treatment mode to meet the new standard's removal requirements for total nitrogen, but the reverse osmosis water yield is low, the cost of cleaning and membrane replacement is high, and the treatment of reverse osmosis membrane concentrate is complicated. practical problems that need to be solved urgently. The reverse osmosis system has better performance for the treatment of stable leachate, that is, shorter filtration time, higher membrane flux and higher salt rejection. Higher organic concentrations in unstable leachate can clog membrane pores and reduce the efficiency of the reverse osmosis system.

The nanofiltration membrane has a strong interception ability for organic pollutants, the interception rate for COD reaches more than 90%, and the interception rate for total nitrogen is only about 50%. It shows that as long as the biochemical reaction is relatively complete, the easily degradable organic pollutants with small molecules can be fully degraded in the biochemical system, and the remaining organic pollutants in the effluent are basically large molecular weight refractory organics, which can be stably removed by nanofiltration membranes. Compared with the reverse osmosis membrane, the nanofiltration membrane has a larger pore size, cannot intercept monovalent salt ions, does not cause the accumulation of TDS, and concentrates are easier to handle. The water output of nanofiltration concentrate is also higher than that of reverse osmosis. When "nanofiltration + nanofiltration concentrate 3-stage reduction" is used in the transformation process of the fourth phase leachate treatment plant of Laogang domestic waste landfill, the nanofiltration The clear liquid yield of the filtration treatment process is as high as 97%, which is much higher than the 71% clear liquid yield of the traditional reverse osmosis process.

Usually, the first-level nanofiltration cannot meet the standard requirements stably. Second-level and third-level nanofiltration can be used in the project. At the same time, the concentrated solution of the second-level nanofiltration is mixed with the clear water of the first-level nanofiltration to increase the water production rate of the system. "MBR+two-stage NF" is applied to treat old leachate in landfill, which can treat 425m ³ /d of leachate. Since the concentrated liquid in the secondary nanofiltration contains high total nitrogen, it will also increase the difficulty of removing total nitrogen after mixing. Therefore, the removal of total nitrogen is the key to replace reverse osmosis with nanofiltration.

Because the chemical reaction principle is simple, the operation is convenient, and the construction cost is low, the present invention aims at the nanofiltration concentrated liquid and clear liquid effluent, and develops an emergency treatment plan for the total nitrogen of the effluent when multi-stage nanofiltration is used as advanced treatment, and then applied to leachate The removal of total nitrogen increases the guarantee for the effluent to meet the standard. This technical method has not been reported yet.

Contents of the invention

Aiming at the deficiencies of the prior art, the object of the present invention is to provide an emergency treatment method for the total nitrogen of nanofiltration concentrated liquid exceeding the standard. The Na ₂ S multi-stage nanofiltration advanced treatment emergency denitrification process adopted in the emergency treatment method has a simple chemical reaction principle, convenient operation, and low construction cost investment. Na ₂ S is added to the refluxing secondary nanofiltration concentrated liquid to remove the total Nitrogen proves the possibility of replacing reverse osmosis with nanofiltration, which has high economic, social and environmental benefits.

For reaching this purpose, the present invention adopts following technical scheme:

The invention provides an emergency treatment method in which the total nitrogen of nanofiltration concentrated liquid exceeds the standard, and the emergency treatment method comprises the following steps:

The concentrated nanofiltration solution is subjected to Na ₂ S treatment once, Na ₂ S treatment twice, and Na ₂ S treatment three times.

In view of the characteristics of complex components of leachate and large changes in water quality and quantity with seasons, the present invention provides an emergency treatment method for total nitrogen exceeding the standard in nanofiltration concentrated liquid. The emergency treatment method is simple in principle, easy to operate, and low in construction costs. Higher economic and social environmental benefits.

As a preferred technical solution of the present invention, said one-time Na ₂ S treatment includes:

Mixing the concentrated nanofiltration solution and the first Na ₂ S, performing a reaction and then filtering, and then performing an acid-base adjustment, standing still and filtering to obtain the first supernatant.

As a preferred technical solution of the present invention, the secondary Na ₂ S treatment includes:

The first supernatant and the second Na ₂ S are mixed, filtered after the second reaction, and then the second acid-base adjustment is performed, and the second supernatant is obtained after standing and filtering.

As a preferred technical solution of the present invention, the three Na ₂ S treatments include:

The second supernatant and the third Na ₂ S were mixed, and three acid-base adjustments were performed after the three reactions.

The reaction principle of the first Na ₂ S treatment, the second Na ₂ S treatment and the third Na ₂ S treatment in the present invention is: by adding Na ₂ S, the solution contains a large amount of negative divalent sulfide ions, and then by adjusting the The pH reacts 6H ⁺ +5S ^2- +2NO ₃ ^- = 2NO↑+5S↓+3H ₂ O, thereby reducing the nitrogen content of the nanofiltration concentrate.

It is worth noting that after the three Na ₂ S treatment processes of the present invention, there is no precipitation after adding Na ₂ S. The reason is that after the addition of sodium sulfide three times, most of the nitrate ions in the concentrated solution have been dissolved in the acidic environment. React with negative divalent sulfide ions, and a small amount of nitrate no longer participates in the reaction.

As a preferred technical solution of the present invention, the dosage ratio of the first Na ₂ S and the nanofiltration concentrate is (0.5-2.0) mol:100mL, for example, it can be 0.5mol:100mL, 1.0mol:100mL, 1.5mol: 100mL or 2.0mol:100mL, but not limited to the listed values, other unlisted values within the range of values are also applicable.

Preferably, the temperature of the first Na ₂ S treatment is 18-30°C, such as 18°C, 20°C, 22°C, 24°C, 26°C, 28°C or 30°C, but not limited to the listed values, Other unrecited values within the range of values also apply.

Preferably, the time for the first reaction is 10-15 minutes, for example, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes or 15 minutes, but not limited to the listed values, and other unlisted values within the numerical range are also applicable.

Preferably, the end point of the primary acid-base adjustment is a pH of 8.0 to 10.0, such as 8.0, 8.4, 8.8, 9.2, 9.6 or 10.0, but not limited to the listed values, other unlisted values within the value range The same applies.

Preferably, the filtration in the first Na ₂ S treatment is medium-speed filter paper filtration.

Preferably, the thickness of the filter membrane used in the filtration is 0.4-0.5mm, for example, it can be 0.4mm, 0.42mm, 0.46mm, 0.48mm or 0.5mm, but it is not limited to the listed values. The listed values also apply.

As a preferred technical solution of the present invention, the amount ratio of the second Na ₂ S to the first supernatant is (0.2-0.5) mol:100mL, for example, it can be 0.2mol:100mL, 0.3mol:100mL, 0.4mol : 100mL or 0.5mol: 100mL, but not limited to the listed numerical values, other unlisted numerical values in the numerical range are also applicable.

Preferably, the temperature of the secondary Na ₂ S treatment is 18-30°C, such as 18°C, 20°C, 22°C, 24°C, 26°C, 28°C or 30°C, but not limited to the listed values , other unlisted values within the value range are also applicable.

Preferably, the time for the secondary reaction is 8-10 minutes, such as 8 minutes, 9 minutes or 10 minutes, but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

Preferably, the end point of the secondary acid-base adjustment is a pH of 8.0 to 10.0, such as 8.0, 8.4, 8.8, 9.2, 9.6 or 10.0, but not limited to the listed values, other unlisted values within the range Numerical values also apply.

Preferably, the filtration in the secondary Na ₂ S treatment includes medium-speed filter paper filtration with a pore size of 30-50 microns.

As a preferred technical solution of the present invention, the dosage ratio of the third Na ₂ S and the first supernatant is (0.2-0.5) mol:100mL, for example, it can be 0.2mol:100mL, 0.3mol:100mL, 0.4mol : 100mL or 0.5mol: 100mL, but not limited to the listed numerical values, other unlisted numerical values in the numerical range are also applicable.

Preferably, the temperature of the three Na ₂ S treatments is 18-30°C, such as 18°C, 20°C, 22°C, 24°C, 26°C, 28°C or 30°C, but not limited to the listed values, Other unrecited values within the range of values also apply.

Preferably, the time for the three reactions is 5-8 minutes, for example, 5 minutes, 6 minutes, 7 minutes or 8 minutes, but is not limited to the listed values, and other unlisted values within the range of values are also applicable.

Preferably, the end point of the three acid-base adjustments is pH 8.0-10.0, such as 8.0, 8.4, 8.8, 9.2, 9.6 or 10.0, but not limited to the listed values, other unlisted values within the value range The same applies.

As a preferred technical solution of the present invention, the acid-base regulator used in the primary acid-base regulation and secondary acid-base regulation process includes acid solution.

Preferably, the acid solution includes hydrochloric acid and/or sulfuric acid.

As a preferred technical solution of the present invention, the first Na ₂ S, the second Na ₂ S and the third Na ₂ S are all sodium sulfide nonahydrate crystals.

As a preferred technical solution of the present invention, the emergency treatment method of the nanofiltration concentrated liquid total nitrogen exceeding the standard of the present invention comprises the following steps:

(1) At 18-30°C, mix the nanofiltration concentrate and sodium sulfide nonahydrate crystals, filter after one reaction, and then use acid solution to adjust the pH to 8.0-10.0, and then use 0.4-0.5 mm filter membrane to obtain the first supernatant;

Wherein, the dosage ratio of the sodium sulfide nonahydrate crystal and the nanofiltration concentrate is (0.5～2.0)mol:100mL;

(2) At 18-30°C, mix the sodium sulfide nonahydrate crystals and the first supernatant obtained in step (1), filter after the second reaction, and then use an acid solution to adjust the acid-base to a pH of 8.0-10.0, Filtration after standing to obtain the second supernatant;

Wherein, the dosage ratio of the sodium sulfide nonahydrate crystal and the first supernatant is (0.2～0.5)mol:100mL

(3) At 18-30°C, mix sodium sulfide nonahydrate crystals with the second supernatant liquid obtained in step (2), and after three reactions, use acid solution to adjust acid-base three times to pH 8.0-10.0.

The numerical ranges described in the present invention not only include the above-mentioned point values, but also include any point values between the above-mentioned numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention will not exhaustively list the above-mentioned point values. Specific point values covered by the stated ranges.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The emergency treatment method for total nitrogen exceeding the standard in the nanofiltration concentrated liquid provided by the present invention explores the influence of pH, temperature, and the amount of acid radical ion Na ₂ S on the removal effect of total nitrogen in the nanofiltration concentrated liquid, which can be used for leachate effluent Reaching the standard increases protection;

(2) The Na ₂ S multi-stage nanofiltration advanced treatment emergency denitrification process adopted in the emergency treatment method for the total nitrogen exceeding the standard of the nanofiltration concentrated liquid provided by the present invention has simple chemical reaction principle, convenient operation, and low construction cost investment;

(3) The emergency treatment method that the total nitrogen of the nanofiltration concentrate provided by the present invention exceeds the standard is by adding Na in the secondary nanofiltration concentrate of backflow _S thereby removes total nitrogen, proves the possibility of nanofiltration replacing reverse osmosis, has Higher economic and social environmental benefits.

Description of drawings

Fig. 1 is a schematic diagram of the impact of the emergency treatment method for total nitrogen exceeding the standard of the nanofiltration concentrated liquid provided by the embodiment of the present invention on the total nitrogen removal effect of the nanofiltration concentrated liquid;

Among them, (a) is the change of total nitrogen removal rate when the pH value is changed; (b) is the change of total nitrogen removal rate when the acid ion is changed; (c) is the change of total nitrogen removal rate when the temperature is changed; (d) is Na ₂ S The total nitrogen removal rate changes when the addition amount changes;

Fig. 2 is a broken line diagram of the total nitrogen removal effect of the nanofiltration concentrated liquid by the emergency treatment method provided by Examples 1 and 15 of the present invention.

Detailed ways

The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and through specific implementation methods. It should be clear to those skilled in the art that the examples are only for helping to understand the present invention, and should not be regarded as specific limitations on the present invention.

The source of some components in the following examples and comparative examples is as follows:

The sodium sulfide nonahydrate crystals, hydrochloric acid and sulfuric acid were all purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. and were analytically pure.

Example 1

This embodiment provides an emergency treatment method in which the total nitrogen of the nanofiltration concentrated liquid exceeds the standard, and the emergency treatment method includes the following steps:

(1) At 20°C, mix the nanofiltration concentrate and sodium sulfide nonahydrate crystals, filter after a reaction for 12 minutes, and then use sulfuric acid to adjust the acid-base to pH 9.0, and then filter it with a 0.45mm filter membrane to obtain the first supernatant;

Wherein, the consumption ratio of described sodium sulfide nonahydrate crystal and nanofiltration concentrate is 1.5mol:100mL;

(2) At 20°C, mix the sodium sulfide nonahydrate crystals and the first supernatant liquid obtained in step (1), filter after the second reaction for 9 minutes, and then use sulfuric acid to adjust the acid-base to pH 9.0, and filter after standing Obtain the second supernatant;

Wherein, the consumption ratio of described sodium sulfide nonahydrate crystal and the first supernatant liquid is 0.5mol:100mL;

(3) At 20°C, mix sodium sulfide nonahydrate crystals and the second supernatant liquid obtained in step (2), perform three acid-base adjustments to pH 9.0 with sulfuric acid after three reactions for 7 minutes;

Wherein, the dosage ratio of the sodium sulfide nonahydrate crystal and the second supernatant liquid is 0.5mol:100mL.

Example 2

This embodiment provides an emergency treatment method in which the total nitrogen of the nanofiltration concentrated liquid exceeds the standard. The difference between the emergency treatment method and Example 1 is only that:

In this embodiment, the end points of the first acid-base adjustment, the second acid-base adjustment and the third acid-base adjustment described in steps (1)-(3) are modified to a pH value of 5.0.

Example 3

This embodiment provides an emergency treatment method in which the total nitrogen of the nanofiltration concentrated liquid exceeds the standard. The difference between the emergency treatment method and Example 1 is only that:

In this embodiment, the end point of the primary acid-base adjustment described in step (1) is modified to a pH value of 6.0.

Example 4

This embodiment provides an emergency treatment method in which the total nitrogen of the nanofiltration concentrated liquid exceeds the standard. The difference between the emergency treatment method and Example 1 is only that:

In this embodiment, the end point of the primary acid-base adjustment described in step (1) is modified to a pH value of 7.0.

Example 5

This embodiment provides an emergency treatment method in which the total nitrogen of the nanofiltration concentrated liquid exceeds the standard. The difference between the emergency treatment method and Example 1 is only that:

In this embodiment, the end point of the primary acid-base adjustment described in step (1) is modified to a pH value of 8.0.

Example 6

This embodiment provides an emergency treatment method in which the total nitrogen of the nanofiltration concentrated liquid exceeds the standard. The difference between the emergency treatment method and Example 1 is only that:

In this embodiment, the end point of the primary acid-base adjustment described in step (1) is modified to a pH value of 10.0.

Example 7

This embodiment provides an emergency treatment method in which the total nitrogen of the nanofiltration concentrated liquid exceeds the standard. The difference between the emergency treatment method and Example 1 is only that:

In this embodiment, the sulfuric acid described in steps (1)-(3) is modified to hydrochloric acid.

Example 8

This embodiment provides an emergency treatment method in which the total nitrogen of the nanofiltration concentrated liquid exceeds the standard. The difference between the emergency treatment method and Example 2 is only that:

In this embodiment, the sulfuric acid described in steps (1)-(3) is modified to hydrochloric acid.

Example 9

This embodiment provides an emergency treatment method in which the total nitrogen of the nanofiltration concentrated liquid exceeds the standard. The difference between the emergency treatment method and Example 3 is only:

In this embodiment, the sulfuric acid described in steps (1)-(3) is modified to hydrochloric acid.

Example 10

This embodiment provides an emergency treatment method in which the total nitrogen of the nanofiltration concentrated liquid exceeds the standard. The difference between the emergency treatment method and Example 4 is only:

In this embodiment, the sulfuric acid described in steps (1)-(3) is modified to hydrochloric acid.

Example 11

This embodiment provides an emergency treatment method in which the total nitrogen of the nanofiltration concentrated liquid exceeds the standard. The difference between the emergency treatment method and Example 5 is only that:

In this embodiment, the sulfuric acid described in steps (1)-(3) is modified to hydrochloric acid.

Example 12

This embodiment provides an emergency treatment method in which the total nitrogen of the nanofiltration concentrated liquid exceeds the standard. The difference between the emergency treatment method and Example 6 is only:

In this embodiment, the sulfuric acid described in steps (1)-(3) is modified to hydrochloric acid.

Example 13

This embodiment provides an emergency treatment method in which the total nitrogen of the nanofiltration concentrated liquid exceeds the standard. The difference between the emergency treatment method and Example 1 is only that:

This embodiment provides 4 sets of experiments, which are respectively: In this embodiment, the reaction temperatures described in steps (1)-(3) are respectively modified to 30°C, 40°C, 50°C and 60°C.

The results of the total nitrogen removal rate of the emergency treatment methods carried out at different temperatures are shown in Fig. 1(c).

Example 14

This embodiment provides an emergency treatment method in which the total nitrogen of the nanofiltration concentrated liquid exceeds the standard. The difference between the emergency treatment method and Example 1 is only that:

This embodiment provides 4 sets of experiments, respectively: In this embodiment, the dosage of sodium sulfide nonahydrate crystals described in step (1) is respectively modified to 0.25 mol, 0.5 mol, 1.0 mol and 2 mol.

The results of the total nitrogen removal rate of the emergency treatment method carried out at different dosages of sodium sulfide nonahydrate crystals are shown in Figure 1(d).

Example 15

This embodiment provides an emergency treatment method in which the total nitrogen of the nanofiltration concentrated liquid exceeds the standard. The difference between the emergency treatment method and Example 1 is only that:

This embodiment provides 4 sets of experiments, respectively: In this embodiment, the endpoints of the three acid-base adjustments described in step (3) are respectively modified to pH values of 5.0, 6.0, 7.0, 8.0 and 10.0.

Modifying the pH of the three acid-base adjustments described in step (3) will affect the total nitrogen removal rate, and the results are shown in Figure 2.

Comparative example 1

This comparative example provides a kind of emergency treatment method that the total nitrogen of the nanofiltration concentrated liquid exceeds the standard, and the difference between the emergency treatment method and Example 1 is only:

In this comparative example, the three Na ₂ S treatments described in step (3) were omitted.

The total nitrogen removal rate after the nanofiltration concentrate is treated by the treatment method provided in Examples 1-6 is shown in Figure 1(a). Adopt embodiment 1-12 to provide treatment method to the total nitrogen removal rate after the nanofiltration concentrate is processed as shown in Figure 1 (b), and Figure 1 (b) represents the influence of acid radical ion on removing the total nitrogen of nanofiltration concentrate .

According to Figure 1(a), it can be seen that when a small amount of sulfuric acid is added dropwise to a high pH value, the content of hydrogen ions in the solution is less, which is not conducive to the reaction between Na ₂ S and nitrate, and the removal rate of total nitrogen is low; gradually increase the content of hydrogen ions to When the pH value is 9, as the content of hydrogen ions in the solution increases, the target reaction is promoted, and the total nitrogen removal rate increases to a certain extent, up to about 18.5%; continue to increase the content of hydrogen ions, and a large amount of white precipitate can be observed. , and accompanied by the generation of more irritating gases, the removal rate of total nitrogen decreased.

According to Figure 1(b), it can be seen that when the pH is 9 and above, due to being in a slightly stronger alkaline environment, the sulfide ions and sulfate radicals hardly undergo a neutralization reaction, and have no effect on the reaction between Na ₂ S and nitrate radicals . However, in weakly alkaline, neutral and acidic environments, the increase of sulfate promotes the neutralization reaction, consumes Na ₂ S, and reduces the removal rate of total nitrogen. Therefore, it is more suitable to use hydrochloric acid instead of sulfuric acid to adjust the acidity and alkalinity of the solution after removing the precipitate.

According to Figure 1(c), it can be seen that with the increase of temperature, the reaction efficiency of Na ₂ S to reduce nitrate does not increase significantly. Considering economic factors and reaction effects, the removal rate of about 18% at 20°C is the most ideal.

According to Fig. 1(d), it can be seen that the effect of the addition amount of Na ₂ S on the removal of total nitrogen in the nanofiltration concentrate. As the content of hydrogen ions in the filtered solution increases, the more hydrogen sulfide is generated by adjusting the pH, the more sulfur ions participate in the removal of total nitrogen, and the removal rate reaches the peak when the addition amount is 1.5mol/L.

According to Figure 2, it can be seen that: in the process of adjusting the acidity of the reaction with sulfuric acid, and the pH value from large to small, it is observed that a small amount of light yellow and white precipitates are gradually produced, accompanied by the generation of rotten egg odor gas; and the pH value when a small amount of sulfuric acid is added dropwise Higher, the hydrogen ion content in the solution is less, which is not conducive to the reaction of sodium sulfide and nitrate; when the pH value is gradually adjusted to 9, as the hydrogen ion content in the solution increases, the target reaction is promoted, and the total nitrogen removal rate has a certain amount increase, up to about 17.5%.

In summary, the emergency treatment method for total nitrogen exceeding the standard in the nanofiltration concentrated liquid provided by the present invention explores the influence of pH, temperature, and the amount of acid radical ion Na ₂ S on the removal effect of total nitrogen in the nanofiltration concentrated liquid. The principle is simple, The operation is convenient, the construction cost is low, and it has high economic and social environmental benefits.

The applicant declares that the present invention illustrates the detailed structural features of the present invention through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of selected components in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the scope of protection and disclosure of the present invention.

The applicant declares that the present invention illustrates the detailed process flow of the present invention through the above-mentioned examples, but the present invention is not limited to the above-mentioned detailed process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent replacement of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the scope of protection and disclosure of the present invention.

Claims (10)

1. an emergency treatment method that the total nitrogen of nanofiltration concentrated liquid exceeds the standard, it is characterized in that, described emergency treatment method comprises: The concentrated nanofiltration solution is subjected to Na ₂ S treatment once, Na ₂ S treatment twice, and Na ₂ S treatment three times. 2. The emergency treatment method according to claim 1, characterized in that, said primary _Na2S treatment comprises: Mixing the concentrated nanofiltration solution and the first Na ₂ S, performing a reaction and then filtering, and then performing an acid-base adjustment, standing still and filtering to obtain the first supernatant. 3. The emergency treatment method according to claim 2, wherein the secondary Na ₂ S treatment comprises: The first supernatant and the second Na ₂ S are mixed, filtered after the second reaction, and then the second acid-base adjustment is performed, and the second supernatant is obtained after standing and filtering. 4. The emergency treatment method according to claim 3, wherein the three Na ₂ S treatments include: The second supernatant and the third Na ₂ S were mixed, and three acid-base adjustments were performed after the three reactions. 5. The emergency treatment method according to claim 2, wherein the dosage ratio of the first Na ₂ S and the nanofiltration concentrate is (0.5～2.0)mol:100mL; Preferably, the temperature of the first Na ₂ S treatment is 18-30°C; Preferably, the time for the first reaction is 10 to 15 minutes; Preferably, the end point of the primary acid-base adjustment is pH 8.0-10.0; Preferably, the filtration in the primary Na ₂ S treatment is ordinary medium-speed filter paper filtration; Preferably, the filter paper used in the filtering has a pore size of 30-50 microns. 6. The emergency treatment method according to claim 3, characterized in that, the dosage ratio of the second Na ₂ S and the first supernatant is (0.2～0.5)mol:100mL; Preferably, the temperature of the secondary Na ₂ S treatment is 18-30°C; Preferably, the time for the secondary reaction is 8 to 10 minutes; Preferably, the end point of the secondary acid-base adjustment is pH 8.0-10.0; Preferably, the filtration in the secondary Na ₂ S treatment includes medium-speed filter paper. 7. The emergency treatment method according to claim 4, characterized in that, the dosage ratio of the third Na ₂ S and the first supernatant is (0.2～0.5)mol:100mL; Preferably, the temperature of the three Na ₂ S treatments is 18-30°C; Preferably, the time for the three reactions is 5 to 8 minutes; Preferably, the end point of the three acid-base adjustments is pH 8.0-10.0. 8. The emergency treatment method according to any one of claims 1-7, characterized in that, the acid-base regulator used in the primary acid-base adjustment and secondary acid-base adjustment process comprises acid solution; Preferably, the acid solution includes hydrochloric acid and/or sulfuric acid. 9. The emergency treatment method according to any one of claims 2-8, characterized in that, the first Na ₂ S, the second Na ₂ S and the third Na ₂ S are all sodium sulfide nonahydrate crystals. 10. The emergency treatment method according to any one of claims 1-9, characterized in that the emergency treatment method comprises the steps of: (1) At 18-30°C, mix the nanofiltration concentrate and sodium sulfide nonahydrate crystals, filter after a reaction for 10-15 minutes, and then use acid solution to adjust the pH to 8.0-10.0, and use it after standing 0.4 ~ 0.5mm membrane filtration to obtain the first supernatant; Wherein, the dosage ratio of the sodium sulfide nonahydrate crystal and the nanofiltration concentrate is (0.5～2.0)mol:100mL; (2) At 18-30°C, mix the sodium sulfide nonahydrate crystals and the first supernatant obtained in step (1), filter after the second reaction for 8-10 minutes, and then use an acid solution to adjust the acid-base to pH 8.0 ~10.0, after standing still, filter to obtain the second supernatant; Wherein, the dosage ratio of the sodium sulfide nonahydrate crystal and the first supernatant is (0.2～0.5)mol:100mL; (3) At 18-30°C, mix sodium sulfide nonahydrate crystals and the second supernatant liquid obtained in step (2), react three times for 5-8 minutes, and use acid solution to adjust acid-base three times to pH 8.0-10.0; Wherein, the dosage ratio of the sodium sulfide nonahydrate crystal and the second supernatant liquid is (0.2-0.5) mol:100mL.