CN109354184B

CN109354184B - Method for improving heavy metal pollution impact load resistance of sewage biological denitrification system

Info

Publication number: CN109354184B
Application number: CN201811298332.7A
Authority: CN
Inventors: 余冉; 高欢; 常岩; 吴俊康; 叶金宇
Original assignee: Southeast University
Current assignee: Southeast University
Priority date: 2018-11-02
Filing date: 2018-11-02
Publication date: 2021-06-01
Anticipated expiration: 2038-11-02
Also published as: CN109354184A

Abstract

The invention belongs to the field of environmental toxicology and biological sewage treatment, and particularly relates to a method for improving the impact load of microorganisms in a biological sewage denitrification system against heavy metal pollution, wherein in the biological sewage denitrification system containing heavy metal pollutants, an N-acyl homoserine lactone compound consisting of a lactonized homoserine part and an acyl side chain with 6-14 carbon atoms is exogenously added; the method has the advantages of simple operation and high treatment efficiency, can obviously improve the capability of resisting the heavy metal impact load of microorganisms by a small amount of medicament, effectively improves the effluent quality of the sewage biological treatment system under the stress of heavy metal pollution, is economic, environment-friendly and free from secondary pollution, can effectively improve the system stability and the system performance recovery capability in time when the sewage biological treatment system is subjected to the toxic impact of heavy metal pollutants, and can be called as a sewage emergency treatment technology under the sudden heavy metal pollution accident.

Description

Method for improving heavy metal pollution impact load resistance of sewage biological denitrification system

Technical Field

The invention belongs to the fields of environmental toxicology and biological sewage treatment, relates to a method for improving impact load resistance of a biological sewage denitrification system, and particularly relates to a method for improving impact load resistance of microorganisms in the biological sewage denitrification system to heavy metal pollution.

Background

With the development of industries such as mining, chemical engineering, electroplating, smelting, electronics and the like, civil solid wastes and the like are improperly buried and stacked, and the heavy metal pollution of the water body is increasingly serious. In the production, use and treatment processes of heavy metals, the heavy metal content in the wastewater can seriously exceed the standard due to the stealing discharge phenomenon of industrial wastewater containing high-concentration heavy metals and sudden pollution accidents of the heavy metals, and finally enters the wastewater through a sewage collecting pipe networkMunicipal sewage treatment systems are an important and common class of pollutants in municipal sewage. If a plurality of heavy metals exist in sludge samples of coastal urban sewage plants in China, the average content of Cu and Cr is the highest and the heavy metals tend to increase continuously; the existing data show that the heavy metal content in the industrial wastewater can be remarkably reduced to 1-100 mg/L after strict process management of enterprises and the control of a necessary metal treatment facility, but is still far higher than the standard of discharge or entering a sewage treatment plant; researches have found that the content of heavy metal zinc in domestic sewage and sludge is highest, copper is secondly, and the Cu content is the same as that of the domestic sewage and the sludge²⁺Obviously stronger harm to the treatment performance of the sewage biological denitrification system than Zn²⁺. Heavy metals are difficult to biodegrade and easy to accumulate and migrate in a biological organism, a traditional physical and chemical treatment unit of a sewage treatment system has a certain removal effect on the heavy metals, but residual heavy metal pollutants still have toxic influence on functional microorganisms in a subsequent biological treatment unit, and can cause decay in severe cases, and the microbial community structure and function disorder of the whole sewage biological treatment system are caused, for example, the activity of related reaction enzymes of biological nitrogen and phosphorus removal is inhibited, metabolic pathways are damaged, so that the removal efficiency of organic matters and nitrogen and phosphorus is influenced, the stability of the system is reduced, and finally the performance deterioration and even collapse of the whole water treatment system can be caused.

Research shows that bacteria can generate and accumulate chemical signal molecules which can diffuse to the outside of cells, and as the density of flora increases, when the concentration of the signal molecules reaches a certain threshold value, the bacteria can carry out intra-species or inter-species information exchange and control the behavior of the population, and the phenomenon is called Quorum Sensing (QS). Quorum sensing and related regulatory bacteria and regulatory genes regulated by N-Acyl Homoserine Lactones (AHLs) are proved to be widely present in a sewage biological denitrification treatment system, such as nitrosomonas and nitrobacter which can generate the AHLs. Nitrite bacteria and nitrifying bacteria, which are typical and widely existing chemoautotrophic bacteria in sewage denitrification processes, are very sensitive to environmental changes and pollutant toxicity stress, and heavy metals entering a sewage treatment system are known to cause the concentration and specific gravity of the nitrifying bacteria, particularly the nitrite bacteria, in activated sludge to be reduced, so that the total nitrogen removal efficiency of the system is reduced. It has been found that AHLs signal molecules have important significance in biological wastewater treatment, such as promotion of aggregation and stabilization of microorganisms, acceleration of formation and maturation of biofilms, improvement of microbial biochemical reaction enzyme activity, promotion of aerobic sludge granulation, and the like, but there is a fresh report on improvement of heavy metal pollutant toxicity stress resistance and alleviation of the influence of heavy metal impact load on a sewage biological system, particularly on biological denitrification performance, by using bacterial quorum sensing.

Disclosure of Invention

The invention solves the problems in the prior art and provides a method for improving the impact load of heavy metal pollutants in a sewage biological denitrification system.

In order to solve the problems, the technical scheme of the invention is as follows:

a method for improving the heavy metal pollution impact load resistance of a sewage biological denitrification system comprises the following steps: in a sewage biological denitrification system containing heavy metal pollutants, an N-acyl homoserine lactone compound consisting of a lactonized homoserine part and an acyl side chain with 6-14 carbon atoms is added externally.

Preferably, the sewage biological nitrogen removal system process is a sequencing batch activated sludge reactor (SBR).

Preferably, the sewage biological denitrification system is used for treating domestic sewage or industrial wastewater containing heavy metals.

Preferably, the heavy metal is Zn²⁺And/or Cu²⁺。

Preferably, the heavy metal content in the sewage biological denitrification system is 1 mg/L-30 mg/L.

Preferably, the N-acylhomoserine lactone is C₆-HSL、C₁₀-HSL、C₁₄-HSL、3-oxo-C₆-HSL、3-oxo-C₁₀-HSL or 3-oxo-C₁₄-one or more of HSL.

Preferably, the N-acylhomoserine lactone is C₁₄-HSL and 3-oxo-C₁₄HSL is dosed in a molar ratio of 1: 1.

Preferably, in the biological sewage denitrification system, the molar concentration of the exogenously added N-acyl homoserine lactone compound is 1-3 mu mol/L.

Compared with the prior art, the invention has the advantages that,

the invention provides a method for improving heavy metal pollution impact load resistance of a sewage biological denitrification system by adding N-acyl homoserine lactone from an external source in the sewage biological denitrification treatment system.

The method has the advantages of simple operation and high treatment efficiency, can obviously improve the capability of resisting the heavy metal impact load of microorganisms by a small amount of medicament, effectively improves the effluent quality of the sewage biological treatment system under the stress of heavy metal pollution, is economic, environment-friendly and free from secondary pollution, can effectively improve the system stability and the system performance recovery capability in time when the sewage biological treatment system is subjected to the toxic impact of heavy metal pollutants, and can be called as a sewage emergency treatment technology under the sudden heavy metal pollution accident.

Drawings

FIG. 1 shows that different concentrations C are added by external sources₁₄-HSL or 3-oxo-C₁₄30mg/L Zn in HSL pair²⁺Influence of the activated sludge biomass of the SBR reactor under toxic impact load, where&Respectively shows that the composition has significant difference (P) compared with a control group and a group only subjected to heavy metal impact load<0.05)。

FIG. 2 shows that different concentrations C are added by external source₁₄-HSL or 3-oxo-C₁₄30mg/L Zn in HSL pair²⁺Influence of the biological Activity of the activated sludge of the SBR reactor under toxic impact load, wherein&Respectively shows that the composition has significant difference (P) compared with a control group and a group only subjected to heavy metal impact load<0.05)。

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the test examples of the present invention, and the embodiments are implemented on the premise of the technical solutions of the present invention, and detailed implementation manners and specific operation procedures are given, but the scope of protection of the present invention is not limited to the following embodiments. The structural formula and the full name of the N-acyl homoserine lactone compound related in the embodiment are shown in a table 1.

TABLE 1 structural formula and full name of N-acyl homoserine lactone compounds

Example 1

Taking activated sludge from an aeration tank of a certain municipal sewage treatment plant, and preparing artificial simulated wastewater: take 6.5g CH₃COONa，1.2g NaHCO₃，2.3g NH₄Cl，0.11g KH₂PO₄，0.14g K₂HPO₄2mL of trace element liquid (ZnSO)₄·7H₂O 0.6g，MnCl₂·₄H₂O 0.6g，NaMoO₄·₂H₂O 0.3g，CuSO₄·₅H₂O 0.15g，KI 0.15g，H₃BO₃0.75g，CoCl₂·₆H₂O 0.75g，FeCl₃·₆H₂O7.5 g in 1L ultrapure water), 2mL CaCl₂·H₂O solution, 2mL MgSO₄·7H₂And (3) placing the O solution in a culture tank with an effective volume of 10L, and artificially simulating the wastewater quality conditions as follows: COD 500 + -3 mg/L, SOP 5.0 + -0.3 mg/L, NH₄ ⁺-N＝60±2mg/L，NO₂ ^--N＝1.5±0.2mg/L，NO₃ ^--N ═ 4.2 ± 0.6mg/L, pH ═ 7.0 ± 0.5. Inoculating activated sludge into artificial wastewater, acclimating in laboratory for 5 months until water outlet index is stable, and adding ZnSO with final concentration of 30mg/L into SBR reactor with effective volume of 1.5L (reaction period totally 8 h: water inlet 10 min; oxygen deficiency 120 min; aerobic 240 min; precipitation 40 min; water outlet 10 min; idle 60min)₄Or 1mg/L CuSO₄Dissolving, and separately adding C₆-HSL、C₁₀-HSL、C₁₄-HSL、3-oxo-C₆-HSL、3-oxo-C₁₀-HSL or 3-oxo-C₁₄HSL is added into the artificial simulated wastewater inoculated with the sludge at a final concentration of 2 mu mol/L, and a blank control group is arranged and only ZnSO is added₄Or CuSO₄The control group of (1). Sampling and detecting the ammonia nitrogen concentration, the nitrite nitrogen concentration, the nitrate nitrogen concentration and the total nitrogen concentration of effluent subjected to Zn after each group of sludge runs in the SBR reactor for one cycle at the constant temperature of 25 DEG C²⁺Or Cu²⁺The results of the nitrogen concentration of each form of the effluent from the SBR reactor for impact loading of contaminants are shown in tables 2 and 3, respectively.

TABLE 2.30 mg/L Zn²⁺The nitrogen concentration (mg/L) of each form of the effluent of the SBR reactor under the toxic impact load

TABLE 3.1 mg/L Cu²⁺Nitrogen concentration (mg/L) of each form of SBR reactor effluent under toxic impact load

The results of this example show that the addition of different N-acyl homoserine lactones can reduce the heavy metal ion Zn to different degrees²⁺Or Cu²⁺The concentrations of ammonia nitrogen, nitrite nitrogen and nitrate nitrogen in the effluent of the SBR reactor with acute toxic impact load, particularly the addition of N-acyl homoserine lactones with 10 or 14 carbon atoms of acyl side chains can be respectively and obviously improved by 30mg/L Zn²⁺Or 1mg/L Cu²⁺The total nitrogen removal rate of the effluent of the impact-loaded SBR reactor is about 4.92-6.36 percent or 6.97-10.21 percent, which shows that the treatment performance of the biological denitrification system is remarkably recovered under the action of the N-acyl homoserine lactone compound with 10 or 14 carbon atoms of the acyl side chain, and the latter effect is better.

Example 2

Taking activated sludge from an aeration tank of a certain municipal sewage treatment plant, and preparing artificial simulated wastewater: take 6.5g CH₃COONa，1.2g NaHCO₃，2.3g NH₄Cl，0.11g KH₂PO₄，0.14g K₂HPO₄2mL of trace element liquid (ZnSO)₄·₇H₂O 0.6g，MnCl₂·₄H₂O 0.6g，NaMoO₄·₂H₂O 0.3g，CuSO₄·₅H₂O 0.15g，KI 0.15g，H₃BO₃0.75g，CoCl₂·₆H₂O0.75g，FeCl₃·₆H₂O7.5 g in 1L ultrapure water), 2mL CaCl₂·H₂O solution, 2mL MgSO₄·7H₂And (3) placing the O solution in a culture tank with an effective volume of 10L, and artificially simulating the wastewater quality conditions as follows: COD 500 + -3 mg/L, SOP 5.0 + -0.3 mg/L, NH₄ ⁺-N＝60±2mg/L，NO₂ ^--N＝1.5±0.2mg/L，NO₃ ^--N ═ 4.2 ± 0.6mg/L, pH ═ 7.0 ± 0.5. Inoculating activated sludge into artificial wastewater, acclimating in laboratory for 5 months until water outlet index is stable, adding ZnSO with final concentration of 25mg/L into SBR reactor with effective volume of 1.5L (reaction period totally 8 h: water inlet 10 min; oxygen deficiency 120 min; aerobic 240 min; precipitation 40 min; water outlet 10 min; idle 60min)₄And 1mg/L of CuSO₄And separately mixing C with C₆-HSL、C₁₀-HSL、C₁₄-HSL、3-oxo-C₆-HSL、3-oxo-C₁₀-HSL or 3-oxo-C₁₄HSL is added into the artificial simulated wastewater inoculated with the sludge at a final concentration of 2 mu mol/L, and a blank control group is arranged and only ZnSO is added₄And CuSO₄The control group of (1). Sampling and detecting the ammonia nitrogen concentration, the nitrite nitrogen concentration, the nitrate nitrogen concentration and the total nitrogen concentration of effluent subjected to Zn after each group of sludge runs in the SBR reactor for one cycle at the constant temperature of 25 DEG C²⁺And Cu²⁺The results of the nitrogen concentration of the mixed toxicity impact load SBR reactor effluent in each form are shown in Table 4.

TABLE 4.Zn²⁺And Cu²⁺Nitrogen concentration (mg/L) of each form of water discharged from SBR reactor under mixed toxicity impact load

The results of this example show that the addition of different N-acylhomoserine lactones can reduce the content of N-acylhomoserine lactones to different extentsLow heavy metal Zn²⁺And Cu²⁺The addition of the N-acyl homoserine lactone compound with the concentrations of ammonia nitrogen, nitrite nitrogen and nitrate nitrogen in the effluent of the SBR reactor mixed with impact load and the carbon number of the acyl side chain of 6, 10 or 14 can respectively and obviously improve the content of Zn in the effluent²⁺And Cu²⁺The removal rate of ammonia nitrogen and total nitrogen in the effluent of the SBR reactor under the mixed impact load is about 5.67-6.14%, 9.49-9.74% or 10.56-11.03%, which indicates that the treatment performance of the biological denitrification system under the heavy metal toxicity impact load is remarkably recovered under the action of the N-acyl homoserine lactone compound.

Example 3

Taking activated sludge from an aeration tank of a certain municipal sewage treatment plant, and preparing artificial simulated wastewater: take 6.5g CH₃COONa，1.2g NaHCO₃，2.3g NH₄Cl，0.11g KH₂PO₄，0.14g K₂HPO₄2mL of trace element liquid and 2mL of CaCl₂·H₂O solution, 2mL MgSO₄·7H₂And (3) placing the O solution in a culture tank with an effective volume of 10L, and artificially simulating the wastewater quality conditions as follows: COD 500 + -3 mg/L, SOP 5.0 + -0.3 mg/L, NH₄ ⁺-N＝60±2mg/L，NO₂ ^--N＝1.5±0.2mg/L，NO₃ ^--N ═ 4.2 ± 0.6mg/L, pH ═ 7.0 ± 0.5. Inoculating activated sludge into artificial wastewater, acclimating in laboratory for 5 months until water outlet index is stable, adding ZnSO with final concentration of 25mg/L into SBR reactor with effective volume of 1.5L (reaction period totally 8 h: water inlet 10 min; oxygen deficiency 120 min; aerobic 240 min; precipitation 40 min; water outlet 10 min; idle 60min)₄And 1mg/L of CuSO₄Mixing the solution, and adding C₁₀-HSL and C₁₄HSL (molar ratio 1:1) or C₁₄-HSL and 3-oxo-C₁₄HSL (molar ratio 1:1) is prepared into mixed solution, the mixed solution is added into the artificial simulation wastewater inoculated with the sludge at the final concentration of 2 mu mol/L, and a blank control group is arranged and only ZnSO is added₄And CuSO₄The control group of (1). After each group of sludge is operated in the SBR reactor for one period at the constant temperature of 25 ℃, sampling and detecting the ammonia nitrogen concentration, the nitrite nitrogen concentration, the nitrate nitrogen concentration and the total nitrogen concentration of the effluent, and the result is shown in a table 5.

TABLE 5.Zn²⁺And Cu²⁺SBR effluent nitrogen concentration (mg/L) of various forms under mixed toxicity impact load

The results of this example show that addition of C with acyl side chains of the same configuration but of different chain lengths₁₀-HSL and C₁₄HSL mixtures or C with acyl side chains of the same chain length but of different configuration₁₄-HSL and 3-oxo-C₁₄All HSL mixtures can significantly reduce Zn²⁺And Cu²⁺Mixing the ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and total nitrogen concentration of the SBR effluent under the impact load. For addition C₁₀-HSL and C₁₄For an experimental group of the HSL mixture, compared with an experimental group only subjected to heavy metal toxicity impact load, the removal rate of the ammonia nitrogen and the total nitrogen in effluent can be respectively and remarkably improved by about 6.25% and 13.10%; for addition C₁₄-HSL and 3-oxo-C₁₄Compared with the experimental group only subjected to heavy metal toxicity impact load, the experimental group of the HSL mixture can respectively and obviously improve the removal rate of the ammonia nitrogen and the total nitrogen in the effluent by about 7.39 percent and 14.88 percent. The results show that the mixture of N-acylhomoserine lactones is susceptible to Zn²⁺And Cu²⁺The denitrification performance recovery of the SBR system with mixed toxicity impact load has obvious promotion effect, and the mixed adding mode has better promotion effect on the denitrification performance recovery of the SBR system than the mode of only singly adding one compound in the embodiment 2.

Example 4

Taking activated sludge from an aeration tank of a certain municipal sewage treatment plant, and preparing artificial simulated wastewater: take 6.5g CH₃COONa，1.2g NaHCO₃，2.3g NH₄Cl，0.11g KH₂PO₄，0.14g K₂HPO₄2mL of trace element liquid and 2mL of CaCl₂·H₂O solution, 2mL MgSO₄·7H₂And (3) placing the O solution in a culture tank with an effective volume of 10L, and artificially simulating the wastewater quality conditions as follows: COD 500 + -3 mg/L, SOP 5.0 + -0.3 mg/L, NH₄ ⁺-N＝60±2mg/L，NO₂ ^--N＝1.5±0.2mg/L，NO₃ ^--N ═ 4.2 ± 0.6mg/L, pH ═ 7.0 ± 0.5. Inoculating activated sludge into artificial wastewater, acclimating in laboratory for 5 months until water outlet index is stable, adding ZnSO with final concentration of 25mg/L into SBR reactor with effective volume of 1.5L (reaction period totally 8 h: water inlet 10 min; oxygen deficiency 120 min; aerobic 240 min; precipitation 40 min; water outlet 10 min; idle 60min)₄And 1mg/L of CuSO₄Mixing the solution, and adding C₁₄-HSL and 3-oxo-C₁₄HSL is prepared into mixed solution in a molar ratio of 2:1 or 1:2 respectively and is added into the artificial simulation wastewater inoculated with the sludge in a final concentration of 2 mu mol/L respectively, and a blank control group is arranged and only ZnSO is added₄And CuSO₄The control group of (1). After each group of sludge is operated in the SBR reactor for one period at the constant temperature of 25 ℃, sampling and detecting the ammonia nitrogen concentration, the nitrite nitrogen concentration, the nitrate nitrogen concentration and the total nitrogen concentration of the effluent, and the result is shown in a table 6.

TABLE 6.Zn²⁺And Cu²⁺SBR effluent nitrogen concentration (mg/L) of various forms under mixed toxicity impact load

The results of this example show that addition of C₁₄-HSL and 3-oxo-C₁₄The HSL mixture can reduce Zn obviously²⁺And Cu²⁺Mixing the ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and total nitrogen concentration of the SBR effluent under the impact load. For C₁₄-HSL and 3-oxo-C₁₄-HSL in molar ratios 2:1, 1:1 and 1:2, compared with the experimental group only subjected to the heavy metal toxicity impact load, the removal rates of the effluent ammonia nitrogen and the total nitrogen can be respectively and obviously improved by about 7.27 percent and 11.94 percent, 8.32 percent and 13.05 percent, 7.66 percent and 11.43 percent. The results show that C₁₄-HSL and 3-oxo-C₁₄The HSL mixture is added to the Zn in a molar ratio of 1:1²⁺And Cu²⁺The significant promotion of the recovery of denitrification performance of the SBR system with mixed toxic impact loading is best.

Example 5

From a certain cityTaking activated sludge from an aeration tank of a municipal sewage treatment plant, and configuring artificial simulation wastewater: take 6.5g CH₃COONa，1.2g NaHCO₃，2.3g NH₄Cl，0.11g KH₂PO₄，0.14g K₂HPO₄2mL of trace element liquid and 2mL of CaCl₂·H₂O solution, 2mL MgSO₄·7H₂And (3) placing the O solution in a culture tank with an effective volume of 10L, and artificially simulating the wastewater quality conditions as follows: COD 500 + -3 mg/L, SOP 5.0 + -0.3 mg/L, NH₄ ⁺-N＝60±2mg/L，NO₂ ^--N＝1.5±0.2mg/L，NO₃ ^--N ═ 4.2 ± 0.6mg/L, pH ═ 7.0 ± 0.5. Inoculating activated sludge into artificial wastewater, acclimating in laboratory for 5 months until water outlet index is stable, adding ZnSO with final concentration of 30mg/L into SBR reactor with effective volume of 1.5L (reaction period totally 8 h: water inlet 10 min; oxygen deficiency 120 min; aerobic 240 min; precipitation 40 min; water outlet 10 min; idle 60min)₄A solution, and mixing C₁₄-HSL or 3-oxo-C₁₄HSL is added into the artificial simulated wastewater inoculated with the sludge respectively at the final concentration of 1 mu mol/L, 2 mu mol/L, 3 mu mol/L, 4 mu mol/L or 5 mu mol/L, a blank control group is arranged, and only ZnSO is added₄And a control group which is only added with AHLs with corresponding concentration (1-5 mu mol/L). After each group of sludge is operated in an SBR reactor under the constant temperature condition of 25 ℃ for one cycle, sampling and detecting the ammonia nitrogen concentration, the nitrite nitrogen concentration, the nitrate nitrogen concentration and the total nitrogen concentration of water, the results are respectively shown in tables 7 and 8, MLVSS (mixed liquor volatile suspended solid concentration) of the sludge after one cycle of reaction is measured to represent the biomass of an activated sludge treatment system (figure 1), and SOUR (specific oxygen consumption rate) of the activated sludge is simultaneously measured to represent the existence of N-acyl homoserine lactone compounds to 30mg/L Zn²⁺Effect of biological activity of activated sludge under toxic impact load (figure 2).

TABLE 7.30 mg/L Zn²⁺The nitrogen concentration (mg/L) of each form of SBR effluent water under the toxic impact load (adding C)₁₄-HSL group)

TABLE 8.30 mg/L Zn²⁺The nitrogen concentration (mg/L) of each form of SBR effluent is added with 3-oxo-C under the toxic impact load₁₄-HSL group)

The result of the embodiment shows that the adding concentration of C is 1-4 mu mol/L₁₄-HSL or 3-oxo-C₁₄HSL is reduced by 30mg/L Zn to various degrees²⁺The ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and total nitrogen concentration of the SBR effluent under impact load are added by 1-5 mu M C from an external source₁₄-HSL or 3-oxo-C₁₄HSL has no significant influence on the biological denitrification treatment performance of sewage. For addition C₁₄Experimental group of-HSL, compared to Zn alone²⁺Experimental groups for toxic impact loads, C at concentrations of 2. mu. mol/L or 3. mu. mol/L₁₄The HSL can respectively and obviously improve the total nitrogen removal rate of the effluent by about 5.86 percent and 5.82 percent, and the concentration of C is 1-3 mu mol/L₁₄HSL can significantly increase activated sludge bio-content by about 13.71%, 15.14% and 17.14%, respectively; when the concentration is continuously increased, the concentration of ammonia nitrogen and total nitrogen in effluent is obviously increased, the biomass of activated sludge is reduced, the biological activity is reduced, and when the concentration reaches 5 mu mol/L, the slow release effect is not even realized. For the addition of 3-oxo-C₁₄Experimental group of-HSL, compared to Zn alone²⁺Experimental group of toxic impact load, 3-oxo-C with concentration of 1-3 mu mol/L₁₄HSL can respectively and obviously improve the total nitrogen removal rate of effluent by about 4.39%, 6.16% and 6.04%, and respectively and obviously improve the biomass of activated sludge by about 10.58%, 17.72% and 17.15%; when the concentration continues to rise, the removal rate of the ammonia nitrogen and the total nitrogen in the effluent is obviously reduced, the biomass of the activated sludge is reduced, the biological activity is reduced, and the slow release effect is not achieved. Comprehensive factors such as cost and efficiency, and C with the concentration range of 1-3 mu mol/L₁₄-HSL or 3-oxo-C₁₄HSL vs Zn at 30mg/L²⁺Toxic impactThe denitrification performance recovery of the SBR system under load has better promotion effect.

It should be noted that the above-mentioned embodiments are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention, and all equivalent substitutions or substitutions made on the above-mentioned embodiments are included in the scope of the present invention.

Claims

1. A method for improving heavy metal pollution impact load resistance of a sewage biological denitrification system is characterized in that an N-acyl homoserine lactone compound consisting of a lactonized homoserine part and an acyl side chain with 6-14 carbon atoms is added into the sewage biological denitrification system containing heavy metal pollutants in an exogenous mode;

the heavy metal is Zn²⁺And/or Cu²⁺。

2. The method of claim 1, wherein the biological denitrification system is a sequencing batch activated sludge process.

3. The method for improving the impact load resistance against heavy metal pollution of a biological nitrogen removal system for sewage as claimed in claim 1, wherein the object to be treated by the biological nitrogen removal system for sewage is domestic sewage or industrial wastewater containing heavy metals.

4. The method for improving the impact load of the biological nitrogen removal system for sewage treatment as claimed in claim 1, wherein the concentration of heavy metal is 1-30 mg/L.

5. The method of improving the impact load of heavy metal pollution in a biological nitrogen removal system from wastewater according to claim 1, wherein said N-acylhomoserine lactone compound is C₆-HSL、C₁₀-HSL、C₁₄-HSL、3-oxo-C₆-HSL、3-oxo-C₁₀-HSL or 3-oxo-C₁₄-one or more of HSL.

6. The method of improving the impact load of heavy metal pollution in a biological nitrogen removal system from wastewater according to claim 1, wherein said N-acylhomoserine lactone compound is C₁₄-HSL and 3-oxo-C₁₄HSL is dosed in a molar ratio of 1: 1.

7. The method for improving the impact load resistance of the sewage biological denitrification system of claim 1, wherein the molar concentration of the exogenously added N-acyl homoserine lactone compound in the sewage biological denitrification system is 1-3 μmol/L.