Treatment method of high-salt and high-ammonia-nitrogen wastewater

Abstract

The invention relates to the technical field of wastewater purification, and discloses a treatment method of high-salt and high-ammonia-nitrogen wastewater. The method comprises the following steps: (1) carrying out nitration treatment on the high-salt and high-ammonia-nitrogen wastewater under an aerobic condition to obtain first effluent containing nitrate; (2) carrying out denitrification treatment on the first effluent under an anaerobic condition to obtain nitrogen and purified water; wherein the nitrification treatment and the denitrification treatment are independently carried out in the presence of a compound microbial agent; the compound microbial agent at least comprises the following components: Thioalkalivibrio versutus D301, Thauera sp. Strain SND5 (Single Nucleotide Polymorphism 5), and Rhodococcus corynebacterium bacteria (Rhodococcus corynebacterium bacteria), and is characterized in that the compound microbial agent at least comprises the following components of: Thioalkalivibrio versutus D301, Thauera sp. Strain SND5 (Single Nucleotide Polymorphism 5) and Rhodococcus corynebacterium bacteria (Rhodococcus corynebacterium bacteria (Rhodococcus corynebacterium bacteria). The method provided by the invention can effectively remove ammonia nitrogen contained in the high-salt and high-ammonia-nitrogen wastewater, so that the concentration of the ammonia nitrogen in the purified water is lower than 8mg / L, and the emission requirement is met. The method also has the characteristics of extremely small sludge discharge amount, quick start and stable purification effect.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater purification, and in particular to a method for treating high-salt and high-ammonia nitrogen wastewater. Background Art

[0002] The flue gas desulfurization and denitrification wastewater produced by power plants contains a large amount of ammonia nitrogen, and the salinity, mainly sulfate, can reach up to 80g / L. Taking the wastewater from the fourth power station of Sinopec Zhenhai Refining and Chemical Company as an example, the SO4 2- The concentration of organic carbon is 45-50g / L, the average ammonia nitrogen concentration is 43.17mg / L, and the COD concentration is 15-56mg / L, showing the characteristics of low organic carbon, high salt and high ammonia nitrogen. According to the requirements of water pollution prevention and control, the ammonia nitrogen concentration index in the discharged wastewater should be controlled not higher than 8mg / L.

[0003] Generally, for wastewater containing ammonia nitrogen with low salt content, the activated sludge method or biofilm method can be used to effectively remove ammonia nitrogen through nitrification-denitrification. However, for wastewater containing high salt and ammonia nitrogen, the high concentration of salt contained in it will reduce the metabolic function of microbial enzymes, inhibit their activity, and even cause the death of microorganisms, causing the existing methods to sharply reduce the removal effect of ammonia nitrogen when treating wastewater containing ammonia nitrogen with a salinity of more than 30g / L.

[0004] Therefore, there is an urgent need to provide a treatment method for high-salt and high-ammonia nitrogen wastewater to effectively reduce the ammonia nitrogen content in such wastewater and achieve discharge compliance. Summary of the invention

[0005] Aiming at the problem that the existing treatment methods are not effective in removing ammonia nitrogen contained in high-salt and high-ammonia nitrogen wastewater, the present invention provides a treatment method for high-salt and high-ammonia nitrogen wastewater.

[0006] In order to achieve the above object, the present invention provides a method for treating high-salt and high-ammonia nitrogen wastewater, the method comprising:

[0007] (1) subjecting the high-salt and high-ammonia nitrogen wastewater to nitrification treatment under aerobic conditions to obtain a first effluent containing nitrate;

[0008] (2) subjecting the first effluent to denitrification treatment under anaerobic conditions to obtain nitrogen and purified water;

[0009] Wherein, the nitrification treatment and the denitrification treatment are each independently carried out in the presence of a composite microbial agent;

[0010] The composite microbial agent at least comprises Thioalkalivibrio versutus D301, Thauera sp. strain SND5 and Rhodococcus corynebacterioides.

[0011] Through the above technical scheme, the present invention targets wastewater containing high salt concentration and high ammonia nitrogen concentration (in the high-salt and high-ammonia nitrogen wastewater, the salt concentration is 30-60g / L, the ammonia nitrogen concentration is 30-80mg / L, and the COD value is 30-80mg / L). Based on a specific composite microbial agent, the wastewater is subjected to nitrification treatment under aerobic conditions and denitrification treatment under anaerobic conditions in sequence, so as to effectively remove the ammonia nitrogen contained in the wastewater. The ammonia nitrogen concentration in the purified water obtained after treatment is reduced to below 8mg / L, preferably to below 2mg / L, and more preferably to below 0.8mg / L, which meets the discharge requirements. In addition, the method has the advantages of small sludge discharge, fast startup, and stable operation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0013] Figure 1 It is a schematic diagram of the device used in Examples 1-4 of the present invention to treat high-salt and high-ammonia nitrogen wastewater.

[0014] Description of Reference Numerals

[0015] 1. Aerobic pool 2. Anoxic pool

[0016] 3. Fixed filler 4. Water inlet pipe

[0017] 5. Aeration device 6. Water inlet pump

[0018] 7. Connecting hole 8. Water outlet pipe

[0019] 9. Water outlet pump DETAILED DESCRIPTION

[0020] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0021] The present invention provides a method for treating high-salt and high-ammonia nitrogen wastewater, the method comprising:

[0022] (1) subjecting the high-salt and high-ammonia nitrogen wastewater to nitrification treatment under aerobic conditions to obtain a first effluent containing nitrate;

[0023] (2) subjecting the first effluent to denitrification treatment under anaerobic conditions to obtain nitrogen and purified water;

[0024] Wherein, the nitrification treatment and the denitrification treatment are each independently carried out in the presence of a composite microbial agent;

[0025] The composite microbial agent at least comprises Thioalkalivibrio versutus D301, Thauera sp. strain SND5 and Rhodococcus corynebacterioides.

[0026] According to the present invention, the high-salt and high-ammonia nitrogen wastewater contains both high-concentration soluble salts and high-concentration ammonia nitrogen. The salts contained may include but are not limited to at least one of sulfates, chlorides and nitrates. The ammonia nitrogen refers to ammonia gaseous nitrogen dissolved in water and ammonium ion nitrogen in an ionized state.

[0027] According to the present invention, the high-salt and high-ammonia nitrogen wastewater contains high-concentration soluble salts, wherein the salt concentration is 30-60 g / L, preferably 30-40 g / L.

[0028] In the present invention, the salt content in the high-salt and high-ammonia nitrogen wastewater is measured as the concentration of all salt compounds. For example, in some embodiments, when the salt in the high-salt and high-ammonia nitrogen wastewater is Na2SO4 and / or K2SO4, the salt content in the high-salt and high-ammonia nitrogen wastewater is measured as the concentration of Na2SO4 and / or K2SO4.

[0029] In the present invention, in the high-salt and high-ammonia nitrogen wastewater, the concentration of total salt compounds is determined according to the method specified in "Gravimetric Method for Determination of Total Salt Content in Water Quality" (HJ / T 51-1999).

[0030] According to the present invention, the high-salt and high-ammonia nitrogen wastewater contains high concentration of ammonia nitrogen, wherein the concentration of ammonia nitrogen is 30-80 mg / L, preferably 30-40 mg / L.

[0031] In the present invention, the concentration of ammonia nitrogen is determined according to the method specified in "Determination of Ammonia Nitrogen in Water Quality - Salicylic Acid Spectrophotometry" (HJ 536-2009).

[0032] According to the present invention, the high-salt and high-ammonia nitrogen wastewater may also contain organic carbon compounds, including but not limited to at least one of acetone, n-hexane, ethyl acetate, isobutanol and benzene series. Preferably, the COD value of the high-salt and high-ammonia nitrogen wastewater is 30-80 mg / L, more preferably 40-50 mg / L.

[0033] In the present invention, the COD value of the wastewater is determined according to the method specified in "Water Quality - Determination of Chemical Oxygen Demand - Rapid Digestion Spectrophotometric Method" (HJ / T 399-2007).

[0034] According to the present invention, preferably, the high-salt and high-ammonia nitrogen wastewater may include but is not limited to flue gas desulfurization and denitrification wastewater from power plants.

[0035] The inventors of the present invention have found that a composite microbial agent comprising at least Thioalkalivibrio versutusD301, Thauera sp.strain SND5 and Rhodococcus corynebacterioides is used to purify the high-salt and high-ammonia nitrogen wastewater. The composite microbial agent can efficiently oxidize and convert the ammonia nitrogen contained in the high-salt and high-ammonia nitrogen wastewater into nitrate under aerobic conditions, and then efficiently reduce the converted nitrate into nitrogen gas under anaerobic conditions, thereby reducing the concentration of ammonia nitrogen in the obtained purified water to below 8 mg / L, and making the purification method provided by the present invention have the characteristics of extremely small sludge discharge, fast startup and stable operation effect.

[0036] According to the present invention, in the composite microbial agent, the biomass of Thioalkalivibrio accounts for 20-40%, the biomass of Tauella accounts for 15-35%, and the biomass of Rhodobacter accounts for 10-36%. When the above biomass proportion range is met, a better ammonia nitrogen removal effect can be achieved.

[0037] In the present invention, the biomass ratio refers to the percentage of the number of a certain type of microorganisms in the composite microbial agent to the total number of microorganisms in the composite microbial agent.

[0038] According to the present invention, on the basis of satisfying the above-mentioned biomass proportion range, preferably, the number ratio of Thioalkalivibrio, Tauella and Rhodobacter in the composite microbial agent is 100:(75-83):(50-87), which can bring about a further improved ammonia nitrogen removal effect.

[0039] According to the present invention, the composite microbial agent may further include Escherichia coli, Bacillus subtilis, etc. in addition to Thioalkalivibrio, Tauella and Rhodobacter.

[0040] In the present invention, the composite microbial agent can be obtained by culturing and domesticating by conventional methods known in the art. The present invention has no particular limitation on the process and conditions used for culturing and domesticating.

[0041] According to the present invention, the activated sludge used in the nitrification and denitrification treatments is selected from at least one of activated sludge from a sewage plant, sludge cultured from seawater sludge, and sludge from high-salinity wastewater.

[0042] In the present invention, the activated sludge of the sewage plant refers to the activated sludge of the domestic sewage treatment plant A 2 The sludge returned from the sedimentation tank in the O (anaerobic-anoxic-aerobic method) process; the sludge cultivated with seawater sludge refers to the sludge obtained by acclimatizing and cultivating the sediment taken from the seawater wetland; the high-salt wastewater sludge refers to the sludge collected from the high-salt sewage treatment facility, and the high-salt wastewater includes but is not limited to high-salt mustard wastewater, concentrated water obtained from the seawater desalination process, etc.

[0043] According to the present invention, preferably, the MLSS value of the activated sludge is 1000-4000 mg / L.

[0044] According to the present invention, the MLSS value refers to the sludge concentration, which can be specifically referred to as the "mixed liquor suspended solids concentration", which represents the total weight of activated sludge solids contained in a unit volume of mixed liquor in a container where the nitrification or denitrification treatment is carried out. In the present invention, the MLSS value is determined according to the method specified in the "Urban Sewage Treatment Plant Sludge Inspection Method" (CJ / T221-2005).

[0045] According to the present invention, the ammonia nitrogen in the high-salt and high-ammonia nitrogen wastewater is efficiently converted into NO3- by the nitrification treatment under the aerobic conditions. Preferably, the conditions of the nitrification treatment include: dissolved oxygen of 3-5 mg / L, temperature of 20-30°C, and pH of 7.5-8.6.

[0046] According to the present invention, the nitrification treatment is also carried out in the presence of bioavailable organic matter. Preferably, the concentration of the bioavailable organic matter added to the wastewater is 1-3 times the ammonia nitrogen concentration in the high-salt and high-ammonia nitrogen wastewater.

[0047] According to the present invention, preferably, in the nitrification treatment, the bioavailable organic matter used is selected from at least one of sodium acetate, glucose and starch.

[0048] According to the present invention, preferably, before the nitrification treatment, sodium bicarbonate (NaHCO3) is added to adjust the pH value of the high-salt and high-ammonia nitrogen wastewater to 7-8.6, so as to supplement the alkalinity consumed by the microorganisms during the nitrification treatment and keep the composite microbial agent highly active.

[0049] According to the present invention, preferably, before the nitrification treatment, a high-salt buffer regulator is added to the high-salt and high-ammonia nitrogen wastewater. The high-salt buffer regulator can promote the microorganisms in the composite microbial agent to control the concentration of compatible solutes in the cells to maintain the balance of osmotic pressure, which is beneficial to maintaining the high activity of the composite microbial agent. Preferably, in the high-salt and high-ammonia nitrogen wastewater, the concentration of the high-salt buffer regulator is 2-20 mg / L.

[0050] In the present invention, preferably, the high-salt buffer regulator comprises at least one of alkaloids, sugars and polyols, and more preferably betaine.

[0051] According to the present invention, after the nitrification treatment, the concentration of nitrate nitrogen in the first effluent obtained is 20-50 mg / L.

[0052] In the present invention, the concentration of nitrate nitrogen is determined according to the method specified in "Determination of Nitrate Nitrogen in Water Quality - Phenol Disulfonic Acid Spectrophotometric Method" (GB 7480-87).

[0053] According to the present invention, the NO3- in the first effluent is efficiently converted into nitrogen gas by denitrification treatment under anaerobic conditions. Preferably, the conditions of the denitrification treatment include: dissolved oxygen < 0.3 mg / L, temperature 20-30°C, pH 7.5-8.6.

[0054] According to the present invention, the denitrification treatment is also carried out in the presence of bioavailable organic matter. Preferably, the concentration of the bioavailable organic matter added to the wastewater is 1.5-2 times the ammonia nitrogen concentration in the high-salinity and high-ammonia nitrogen wastewater.

[0055] According to the present invention, preferably, in the denitrification treatment, the bioavailable organic matter used is selected from at least one of sodium acetate, glucose and starch.

[0056] In the present invention, during the digestion and denitrification processes, the bioavailable organic matter can provide carbon sources, energy and substrates for the composite microbial agent.

[0057] According to the present invention, preferably, the total hydraulic retention time of the nitrification treatment and the denitrification treatment is 20-30h.

[0058] In the present invention, the hydraulic retention time refers to the average time for the sewage to be treated to undergo nitrification or denitrification treatment (i.e., the average residence time of the sewage to be treated in the nitrification treatment container or the denitrification treatment container).

[0059] According to the present invention, in step (2), at least a portion of the purified water is returned to step (1) as at least a portion of the reflux liquid to be subjected to the nitrification treatment together with the high-salt and high-ammonia nitrogen wastewater, which can effectively dilute the ammonia nitrogen concentration in the influent water and reduce the load of the composite microbial agent on degrading ammonia nitrogen.

[0060] In the present invention, in step (2), a portion of the reactant-product system (i.e., reflux liquid) will return to step (1) to continue to participate in the nitrification treatment. The reflux ratio refers to the ratio of the flow rate of the reflux liquid to the flow rate of the denitrification treatment effluent. Preferably, the reflux ratio of the reflux liquid is (2-3):1.

[0061] According to the present invention, after the treatment, the salt concentration in the purified water obtained is 30-60 g / L; the ammonia nitrogen concentration is 0.5-8 mg / L; and the COD value is 20-50 mg / L.

[0062] According to the present invention, the method for treating high-salt and high-ammonia nitrogen wastewater can preferably be implemented in an A / O (anoxic / aerobic) biofilm reactor, such as Figure 1 As shown, the main structure of the A / O biofilm reactor includes: an aerobic tank 1, an anoxic tank 2, and a fixed filler 3 arranged in the aerobic tank 1 and the anoxic tank 2 for fixing the growth of the composite microbial agent; wherein the aerobic tank 1 is provided with a water inlet pipe 4 and an aeration device 5, and the water inlet flow of the water inlet pipe 4 is controlled by a water inlet pump 6; a stirrer is arranged at the bottom of the aerobic tank 1 and the anoxic tank 2 ( Figure 1 The anoxic pool 2 is provided with a water outlet pipe 8, and the water outlet flow of the water outlet pipe 8 is controlled by a water outlet pump 9; wherein the water outlet pipe 8 is provided with two branch outlets, one of which is used as a purified water outlet, and the other branch outlet ( Figure 1 The aerobic tank 1 is connected to the aerobic tank 1 (not shown) to return the reflux liquid to the aerobic tank 1. In the present invention, the specific composition and structure of the A / O biofilm reactor can be selected from those known in the prior art, and the present invention has no particular limitation on this.

[0063] The present invention will be described in detail below by way of examples. In the following examples and comparative examples,

[0064] High-salt and high-ammonia nitrogen wastewater: The wastewater is taken from the flue gas desulfurization and denitrification wastewater of the fourth power station of Sinopec Zhenhai Refining and Chemical Company. Its main components and contents are shown in Table 1.

[0065] Table 1

[0066] Components content Sodium sulfate 40g / L Potassium sulfate 20g / L Ammonia nitrogen 43mg / L COD value 54mg / L

[0067] Note: The content of sodium sulfate in Table 1 is based on the concentration of Na2SO4 in the wastewater, and the content of potassium sulfate is based on the concentration of K2SO4 in the wastewater.

[0068] The following examples 1-4 use Figure 1 The A / O biofilm reactor with the structure shown in the figure is used to treat high-salt and high-ammonia nitrogen wastewater. The effective volumes of the aerobic tank 1 and the anoxic tank 2 are 13.44L and 6.72L respectively, and a 1cm 2 The connecting holes have a built-in fixed filler 3 for fixing the growth of the composite microbial agent, which is a biological rope filler with a filling rate of 17.5%.

[0069] Example 1

[0070] The composite microbial agent is composed of: Thioalkalivibrio (biomass accounts for 25%), Taue's bacteria (biomass accounts for 20%), Rhodobacterium (biomass accounts for 20%), Escherichia coli (biomass accounts for 20%) and Bacillus subtilis (biomass accounts for 15%). The number ratio of Thioalkalivibrio: Taue's bacteria: Rhodobacterium is 100:80:80.

[0071] (1) adding betaine (making the concentration of betaine in the high-salt and high-ammonia nitrogen wastewater reach 15 mg / L) and sodium bicarbonate to the high-salt and high-ammonia nitrogen wastewater to make the pH value of the wastewater 7.5;

[0072] The water inlet pump 6 is started to introduce the wastewater into the aerobic tank 1 through the water inlet pipe 4. Under the action of the composite microbial agent, the wastewater is nitrified (wherein, the dissolved oxygen in the aerobic tank 1 is 4 mg / L through the aeration device 5, and the wastewater temperature in the aerobic tank 1 is controlled to be 28° C. and the pH value is 7.5); in this process, sodium acetate is added to the aerobic tank 1 (so that the concentration of sodium acetate in the wastewater of the aerobic tank is 80 mg / L), and the bottom agitator of the aerobic tank is adjusted to prevent the suspended activated sludge from staying in the aerobic tank 1 or depositing at the bottom of the tank body, so as to ensure that the liquid surface is clear; after the nitrification treatment, the first effluent (the concentration of nitrate nitrogen is 38 mg / L) is obtained and enters the anoxic tank 2 through the connecting hole 7;

[0073] The activated sludge used in nitrification treatment is sludge cultivated from seawater sediment, and the MLSS value is maintained at 3800 mg / L;

[0074] (2) In the anoxic tank 2, under the action of the composite microbial agent, the first effluent is subjected to denitrification treatment (wherein, the dissolved oxygen in the anoxic tank 2 is 0.2 mg / L, the wastewater temperature is controlled to be 28°C, and the pH value is 7.8); in this process, sodium acetate is added to the anoxic tank 2 (so that the concentration of sodium acetate in the wastewater of the anoxic tank is 70 mg / L), and the bottom agitator is adjusted to prevent the suspended activated sludge from staying in the anoxic tank 2 or depositing at the bottom of the tank body to ensure that the liquid surface is clear; after the denitrification treatment, the obtained nitrogen is emptied, and the obtained purified water (wherein the salt, ammonia nitrogen and COD values ​​are shown in Table 2) is divided into two paths, wherein one path is discharged from the reactor through a branch outlet of the outlet pipe 8 under the action of the outlet pump 9, and the other path is returned to the aerobic tank 1 as reflux liquid through another branch outlet of the outlet pipe 8 for the above-mentioned nitrification treatment (the reflux ratio of the reflux liquid is 2.5:1);

[0075] The activated sludge used in denitrification treatment is sludge cultivated from seawater sediment, and the MLSS value is maintained at 3800 mg / L;

[0076] The total hydraulic retention time of nitrification and denitrification treatment is 24h.

[0077] This method can completely treat high-salinity and high-ammonia nitrogen wastewater with a salt concentration of 60g / L within 6 days, and the ammonia nitrogen concentration of the purified water remains stable at 0.5mg / L in the subsequent 70 days, meeting the discharge requirements specified in the "Comprehensive Wastewater Discharge Standard" (GB 8978-1996). The entire operation process produces little sludge, and the sludge discharge cycle is 12 months.

[0078] Example 2

[0079] The composite microbial agent consists of: Thioalkalivibrio (biomass accounts for 20%), Taue's bacteria (biomass accounts for 19%), Rhodobacterium (biomass accounts for 15%), Escherichia coli (biomass accounts for 21%) and Bacillus subtilis (biomass accounts for 25%). The number ratio of Thioalkalivibrio: Taue's bacteria: Rhodobacterium is 100:76:60.

[0080] (1) adding betaine (making the concentration of betaine in the high-salt and high-ammonia nitrogen wastewater reach 5 mg / L) and sodium bicarbonate to the high-salt and high-ammonia nitrogen wastewater to make the pH value of the wastewater 7.5;

[0081] Start the water inlet pump 6, introduce the wastewater into the aerobic tank 1 through the water inlet pipe 4, and perform nitrification treatment on the wastewater under the action of the composite microbial agent (wherein, the dissolved oxygen in the aerobic tank 1 is made 4 mg / L by the aeration device 5, and the wastewater temperature in the aerobic tank 1 is controlled to be 26° C. and the pH value is 7.9); in this process, sodium acetate is added to the aerobic tank 1 (so that the concentration of sodium acetate in the wastewater of the aerobic tank is 80 mg / L), and the bottom agitator of the aerobic tank is adjusted to prevent the suspended activated sludge from staying in the aerobic tank 1 or depositing at the bottom of the tank body, so as to ensure the clarity of the liquid surface; after nitrification treatment, the first effluent (nitrate nitrogen concentration is 40 mg / L) is obtained and enters the anoxic tank 2 through the connecting hole 7;

[0082] The activated sludge used in nitrification treatment is sludge cultivated from seawater sediment, and the MLSS value is maintained at 4000 mg / L;

[0083] (2) In the anoxic tank 2, under the action of the composite microbial agent, the first effluent is subjected to denitrification treatment (wherein, the dissolved oxygen in the anoxic tank 2 is 0.2 mg / L, the wastewater temperature is controlled to be 26°C, and the pH value is 7.9); in this process, sodium acetate is added to the anoxic tank 2 (so that the concentration of sodium acetate in the wastewater of the anoxic tank is 75 mg / L), and the bottom agitator is adjusted to prevent the suspended activated sludge from staying in the anoxic tank 2 or depositing at the bottom of the tank body to ensure that the liquid surface is clear; after the denitrification treatment, the obtained nitrogen is emptied, and the obtained purified water (wherein the salt, ammonia nitrogen and COD values ​​are shown in Table 2) is divided into two paths, wherein one path is discharged from the reactor through a branch outlet of the outlet pipe 8 under the action of the outlet pump 9, and the other path is returned to the aerobic tank 1 as reflux liquid through another branch outlet of the outlet pipe 8 for the above-mentioned nitrification treatment (the reflux ratio of the reflux liquid is 2.6:1);

[0084] The activated sludge used in denitrification treatment is sludge cultivated from seawater sediment, and the MLSS value is maintained at 4000 mg / L;

[0085] The total hydraulic retention time of nitrification and denitrification treatment is 24h.

[0086] This method can completely treat high-salinity and high-ammonia nitrogen wastewater with a salinity of 60g / L within 10 days. In the subsequent 60 days, the ammonia nitrogen concentration of the purified water remains stable at 0.8mg / L, meeting the discharge requirements of the "Comprehensive Wastewater Discharge Standard" (GB 8978-1996). The entire operation process produces little sludge, and the sludge discharge cycle is 12 months.

[0087] Example 3

[0088] The composition of the composite microbial agent is: Thioalkalivibrio (biomass accounts for 23%), Tauella sinensis (biomass accounts for 16%), Rhodobacterium (biomass accounts for 14%), Escherichia coli (biomass accounts for 30%) and Bacillus subtilis (biomass accounts for 17%). The number ratio of Thioalkalivibrio: Tauella sinensis: Rhodobacterium is 100:70:61.

[0089] (1) adding betaine (making the concentration of betaine in the high-salt and high-ammonia nitrogen wastewater be 15 mg / L) and sodium bicarbonate to the high-salt and high-ammonia nitrogen wastewater to make the pH value of the wastewater 7.5;

[0090] The water inlet pump 6 is started to introduce the wastewater into the aerobic tank 1 through the water inlet pipe 4. Under the action of the composite microbial agent, the wastewater is nitrified (wherein, the dissolved oxygen in the aerobic tank 1 is 4 mg / L through the aeration device 5, and the wastewater temperature in the aerobic tank 1 is controlled to be 28° C. and the pH value is 7.5); in this process, sodium acetate is added to the aerobic tank 1 (so that the concentration of sodium acetate in the wastewater of the aerobic tank is 80 mg / L), and the bottom agitator of the aerobic tank is adjusted to prevent the suspended activated sludge from staying in the aerobic tank 1 or depositing at the bottom of the tank body, so as to ensure that the liquid surface is clear; after the nitrification treatment, the first effluent (the concentration of nitrate nitrogen is 42 mg / L) is obtained and enters the anoxic tank 2 through the connecting hole 7;

[0091] The activated sludge used in nitrification treatment is sludge cultivated from seawater sediment, and the MLSS value is maintained at 3800 mg / L;

[0092] (2) In the anoxic tank 2, under the action of the composite microbial agent, the first effluent is subjected to denitrification treatment (wherein, the dissolved oxygen in the anoxic tank 2 is 0.2 mg / L, the wastewater temperature is controlled to be 28°C, and the pH value is 8.2); in this process, sodium acetate is added to the anoxic tank 2 (so that the concentration of sodium acetate in the wastewater of the anoxic tank is 70 mg / L), and the bottom agitator is adjusted to prevent the suspended activated sludge from staying in the anoxic tank 2 or depositing at the bottom of the tank body to ensure that the liquid surface is clear; after the denitrification treatment, the obtained nitrogen is emptied, and the obtained purified water (wherein the salt, ammonia nitrogen and COD values ​​are shown in Table 2) is divided into two paths, wherein one path is discharged from the reactor through a branch outlet of the outlet pipe 8 under the action of the outlet pump 9, and the other path is returned to the aerobic tank 1 as reflux liquid through another branch outlet of the outlet pipe 8 for the above-mentioned nitrification treatment (the reflux ratio of the reflux liquid is 2.5:1);

[0093] The activated sludge used in denitrification treatment is sludge cultivated from seawater sediment, and the MLSS value is maintained at 3800 mg / L;

[0094] The total hydraulic retention time of nitrification and denitrification treatment is 24h.

[0095] This method can completely treat high-salinity and high-ammonia nitrogen wastewater with a salinity of 60g / L within 15 days. In the subsequent 40 days, the ammonia nitrogen concentration of the purified water has remained stable at 7.8mg / L, meeting the discharge requirements of the "Comprehensive Wastewater Discharge Standard" (GB 8978-1996). The entire operation process produces little sludge, and the sludge discharge cycle is 12 months.

[0096] Example 4

[0097] The composite microbial agent is composed of: Thioalkalivibrio (biomass accounts for 38%), Taue's bacteria (biomass accounts for 29%) and Rhodobacter (biomass accounts for 33%), and the number ratio of Thioalkalivibrio: Taue's bacteria: Rhodobacter is 100:76:87.

[0098] (1) adding betaine (making the concentration of betaine in the high-salt and high-ammonia nitrogen wastewater reach 15 mg / L) and sodium bicarbonate to the high-salt and high-ammonia nitrogen wastewater to make the pH value of the wastewater 7.5;

[0099] The water inlet pump 6 is started to introduce the wastewater into the aerobic tank 1 through the water inlet pipe 4. Under the action of the composite microbial agent, the wastewater is nitrified (wherein, the dissolved oxygen in the aerobic tank 1 is 5 mg / L through the aeration device 5, and the wastewater temperature in the aerobic tank 1 is controlled to be 24° C. and the pH value is 7.8); in this process, sodium acetate is added to the aerobic tank 1 (so that the concentration of sodium acetate in the wastewater of the aerobic tank is 75 mg / L), and the bottom agitator of the aerobic tank is adjusted to prevent the suspended activated sludge from staying in the aerobic tank 1 or depositing at the bottom of the tank body, so as to ensure that the liquid surface is clear; after the nitrification treatment, the first effluent (nitrate nitrogen concentration is 42 mg / L) is obtained and enters the anoxic tank 2 through the connecting hole 7;

[0100] The activated sludge used in nitrification treatment is sludge cultivated from seawater sediment, and the MLSS value is maintained at 4000 mg / L;

[0101] (2) In the anoxic tank 2, under the action of the composite microbial agent, the first effluent is subjected to denitrification treatment (wherein, the dissolved oxygen in the anoxic tank 2 is 0.1 mg / L, the wastewater temperature is controlled to be 24°C, and the pH value is 7.8); in this process, sodium acetate is added to the anoxic tank 2 (so that the concentration of sodium acetate in the wastewater of the anoxic tank is 73 mg / L), and the bottom agitator is adjusted to prevent the suspended activated sludge from staying in the anoxic tank 2 or depositing at the bottom of the tank body to ensure the clarity of the liquid surface; after the denitrification treatment, the obtained nitrogen is emptied, and the obtained purified water (wherein the salt, ammonia nitrogen and COD values ​​are shown in Table 2) is divided into two paths, wherein one path is discharged from the reactor through a branch outlet of the outlet pipe 8 under the action of the outlet pump 9, and the other path is returned to the aerobic tank 1 as reflux liquid through another branch outlet of the outlet pipe 8 for the above-mentioned nitrification treatment (the reflux ratio of the reflux liquid is 2.5:1);

[0102] The activated sludge used in denitrification treatment is sludge cultivated from seawater sediment, and the MLSS value is maintained at 4000 mg / L;

[0103] The total hydraulic retention time of nitrification and denitrification treatment is 24h.

[0104] This method can completely treat high-salinity and high-ammonia nitrogen wastewater with a salinity of 60g / L within 12 days, and the ammonia nitrogen concentration of the purified water remains stable at 2mg / L in the subsequent 50 days, meeting the discharge requirements specified in the "Comprehensive Wastewater Discharge Standard" (GB 8978-1996). The entire operation process produces little sludge, and the sludge discharge cycle is 12 months.

[0105] Comparative Example 1

[0106] The method of Example 1 is different in that the composite microbial agent consists of: Bacillus subtilis (biomass accounting for 40%), Tauerella (biomass accounting for 20%), Rhodobacter (biomass accounting for 20%) and Escherichia coli (biomass accounting for 20%). Other conditions are the same as in Example 1.

[0107] After treatment, the salt, ammonia nitrogen and COD values ​​contained in the purified water are shown in Table 2.

[0108] This method can treat high-salt and high-ammonia nitrogen wastewater with a salinity of 60g / L within 20 days. The ammonia nitrogen concentration of the purified water will be at the level of 20mg / L within the subsequent 30 days, which cannot meet the emission requirements specified in the "Integrated Sewage Discharge Standard" (GB 8978-1996).

[0109] Comparative Example 2

[0110] The method of Example 1 is different in that the composite microbial agent consists of: Vibrio thioalkali (biomass accounting for 20%), Tauer (biomass accounting for 34%), Escherichia coli (biomass accounting for 21%) and Bacillus subtilis (biomass accounting for 25%). Other conditions are the same as in Example 1.

[0111] After treatment, the salt, ammonia nitrogen and COD values ​​contained in the purified water are shown in Table 2.

[0112] This method can treat high-salt and high-ammonia nitrogen wastewater with a salinity of 60g / L within 20 days. In the subsequent 30 days, the ammonia nitrogen concentration of the purified water remains stable at 30mg / L, which cannot meet the emission requirements specified in the "Comprehensive Sewage Discharge Standard" (GB 8978-1996).

[0113] Comparative Example 3

[0114] The method of Example 1 is different in that the composite microbial agent consists of: Vibrio thioalkali (biomass accounting for 20%), Rhodobacter (biomass accounting for 34%), Escherichia coli (biomass accounting for 21%) and Bacillus subtilis (biomass accounting for 25%). Other conditions are the same as in Example 1.

[0115] After treatment, the salt, ammonia nitrogen and COD values ​​contained in the purified water are shown in Table 2.

[0116] This method can treat high-salt and high-ammonia nitrogen wastewater with a salinity of 60g / L within 20 days. In the subsequent 30 days, the ammonia nitrogen concentration of the purified water remains stable at 35mg / L, which cannot meet the emission requirements specified in the "Comprehensive Sewage Discharge Standard" (GB 8978-1996).

[0117] Comparative Example 4

[0118] The method of Example 1 is different in that the composite microbial agent consists of: Taue's bacterium (biomass accounting for 39%), Rhodobacter (biomass accounting for 15%), Escherichia coli (biomass accounting for 21%) and Bacillus subtilis (biomass accounting for 25%). Other conditions are the same as in Example 1.

[0119] After treatment, the salt, ammonia nitrogen and COD values ​​contained in the purified water are shown in Table 2.

[0120] This method can treat high-salt and high-ammonia nitrogen wastewater with a salinity of 60g / L within 30 days. In the subsequent 30 days, the ammonia nitrogen concentration of the purified water remained stable at 38mg / L, which could not meet the discharge requirements of the Comprehensive Wastewater Discharge Standard (GB 8978-1996).

[0121] Table 2

[0122]

[0123] Note: The salt concentration in Table 2 is the total concentration of Na2SO4 and K2SO4.

[0124] As can be seen from Table 2, the treatment method for high-salt and high-ammonia nitrogen wastewater provided by the present invention can effectively remove ammonia nitrogen contained in the wastewater, and the concentration of ammonia nitrogen in the purified water obtained after treatment is reduced to below 8 mg / L, among which, Examples 1 and 2 show significant effect advantages, achieving the reduction of the concentration of ammonia nitrogen to below 0.8 mg / L. Comparative Examples 1-4 do not use the specific composite microbial agent of the present invention, and the purification effect is significantly worse than that of Examples 1-4.

[0125] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for treating high-salt and high-ammonia nitrogen wastewater, characterized in that: The method includes: (1) subjecting the high-salt and high-ammonia nitrogen wastewater to nitrification treatment under aerobic conditions to obtain a first effluent containing nitrate; (2) subjecting the first effluent to denitrification treatment under anaerobic conditions to obtain nitrogen and purified water; Wherein, the nitrification treatment and the denitrification treatment are each independently carried out in the presence of a composite microbial agent; The composite microbial agent at least comprises Thioalkalivibrio versutus D301, Thauera sp. strain SND5 and Rhodococcus corynebacterioides.

2. The method according to claim 1, wherein: The salt contained in the high-salt and high-ammonia nitrogen wastewater includes at least one of sulfate, chloride and nitrate; Preferably, the salt concentration in the high-salt and high-ammonia nitrogen wastewater is 30-60 g / L, and more preferably 30-40 g / L; Preferably, the concentration of ammonia nitrogen in the high-sulfate and high-ammonia nitrogen wastewater is 30-80 mg / L, more preferably 30-40 mg / L; Preferably, the COD value of the high-sulfate and high-ammonia nitrogen wastewater is 30-80 mg / L, and more preferably 40-50 mg / L.

3. The method according to claim 1 or 2, wherein: In the composite microbial agent, the biomass of Thioalkalivibrio accounts for 20-40%, the biomass of Tauesella accounts for 15-35%, and the biomass of Rhodobacter accounts for 10-36%; Preferably, in the composite microbial agent, the quantitative ratio of Thioalkalivibrio: Tauella sinensis: Rhodobacterium is 100:(75-83):(50-87).

4. The method according to any one of claims 1 to 3, wherein: The activated sludge used in the nitrification and denitrification treatments is selected from at least one of activated sludge from a sewage plant, sludge cultured from seawater sludge, and sludge from high-salinity wastewater; Preferably, the MLSS value of the activated sludge is 1000-4000 mg / L.

5. The method according to any one of claims 1 to 4, wherein: The conditions of the nitrification treatment include: dissolved oxygen of 3-5 mg / L, temperature of 20-30° C., and pH of 7.5-8.6; Preferably, the nitrification treatment is also carried out in the presence of bioavailable organic matter, and the concentration of the bioavailable organic matter is 1-3 times the ammonia nitrogen concentration in the high-salt and high-ammonia nitrogen wastewater; Preferably, the bioavailable organic matter is selected from at least one of sodium acetate, glucose and starch.

6. The method according to claim 5, wherein: Before the nitrification treatment, a high-salt buffer regulator is added to the high-salt and high-ammonia nitrogen wastewater; Preferably, in the high-salt and high-ammonia nitrogen wastewater, the concentration of the high-salt buffer regulator is 2-20 mg / L; Preferably, the high-salt buffer regulator comprises at least one of alkaloids, sugars and polyols, and more preferably betaine.

7. The method according to any one of claims 1 to 6, wherein: In the first effluent, the concentration of nitrate nitrogen is 20-50 mg / L.

8. The method according to any one of claims 1 to 7, wherein: The conditions of the denitrification treatment include: dissolved oxygen <0.3 mg / L, temperature 20-30°C, pH 7.5-8.6; Preferably, the denitrification treatment is also carried out in the presence of bioavailable organic matter, and the concentration of the bioavailable organic matter is 1.5-2 times the ammonia nitrogen concentration in the high-salt and high-ammonia nitrogen wastewater; Preferably, the bioavailable organic matter is selected from at least one of sodium acetate, glucose and starch; Preferably, the total hydraulic retention time of the nitrification and denitrification treatments is 20-30 hours.

9. The method according to any one of claims 1 to 8, wherein: At least part of the purified water is returned to step (1) to continue participating in the nitrification treatment.

10. The method according to any one of claims 1 to 9, wherein: In the purified water, the salt concentration is 30-60 g / L; the ammonia nitrogen concentration is 0.5-8 mg / L; and the COD value is 20-50 mg / L.

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