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

Abstract

The invention relates to the technical field of wastewater purification, and discloses a high-sulfate high-ammonia-nitrogen wastewater treatment method, which comprises: (1) sequentially carrying out chemical pre-precipitation treatment and neutralization treatment on high-sulfate high-ammonia-nitrogen wastewater to obtain a sulfur-containing precipitation product and first effluent; (2) carrying out sulfate reduction denitrification reaction on the first effluent to obtain methane and second effluent; and (3) carrying out denitrification desulfurization reaction on the second effluent to obtain nitrogen, elemental sulfur and purified water. Through treatment by the method, the concentration of sulfate in the obtained purified water is reduced to 5-10g / L, the concentration of ammonia nitrogen is reduced to 2-6mg / L, and the COD value is 40-50mg / L, so that the synchronous removal of carbon, nitrogen and sulfur in the wastewater is realized, the salinity of the wastewater is greatly reduced, the emission requirement is met, and elemental sulfur is recovered.

Description

Technical Field

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

[0002] The flue gas desulfurization and denitrification wastewater generated 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 sulfate concentration in the water quality 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 sulfate 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 to be no higher than 8mg / L.

[0003] At present, there are few purification engineering cases for this type of wastewater, and physical desalination treatment is mainly used, such as multi-effect evaporation crystallization, reverse osmosis, forward osmosis, electrodialysis, etc. These methods have the disadvantage of generating secondary pollution, and the equipment is complex and the investment and operation costs are high. In addition to the above-mentioned physical methods, although there are also reports of using biological methods (such as biofilm, MBR, etc.) to treat high-salinity and high-ammonia nitrogen wastewater, the wastewater treated by these biological methods is mainly chloride salt, not sulfate. There is no technology for removing high ammonia nitrogen in high sulfate by biological methods. In addition, a simple biological method needs to gradually domesticate microorganisms from low salinity to high salinity. The higher the salinity of the target wastewater to be treated, the longer the adaptation time of the microorganism. The excessive domestication time will not only increase the cost of starting the biological system, but also waste a large amount of dilution water during the startup period, which brings troubles to practical applications. In addition, a simple biological method has the disadvantages of not being able to effectively reduce salinity, low elemental sulfur recovery rate, and unstable purification effect.

[0004] Therefore, providing a method for effectively treating high-sulfate and high-ammonia nitrogen wastewater is of great significance for achieving the harmless and resource-based treatment of such wastewater. Summary of the invention

[0005] Aiming at the problems that high-sulfate and high-ammonia nitrogen wastewater has great difficulty in purification treatment, unsatisfactory removal effect of sulfate and ammonia nitrogen contained therein and high treatment cost, the present invention provides a method for treating high-sulfate and high-ammonia nitrogen wastewater.

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

[0007] (1) subjecting the high-sulfate and high-ammonia nitrogen wastewater to chemical pre-precipitation treatment and neutralization treatment in sequence to obtain a sulfur-containing precipitation product and a first effluent;

[0008] (2) subjecting the first effluent to a sulfate reduction and denitrification reaction to obtain methane and a second effluent;

[0009] (3) subjecting the second effluent to a denitrification and desulfurization reaction to obtain nitrogen, elemental sulfur and purified water.

[0010] Through the above technical solution, the present invention has the following beneficial effects:

[0011] (1) The present invention adopts a treatment method of chemical pre-precipitation-two-stage anaerobic biological method coupling for wastewater containing high concentrations of sulfate and ammonia nitrogen, which can efficiently remove sulfate and ammonia nitrogen contained in the wastewater. After treatment, the concentration of sulfate in the purified water obtained is reduced to 5-10g / L, the concentration of ammonia nitrogen is reduced to 2-6mg / L, and the COD value is 40-50mg / L, achieving the simultaneous removal of carbon, nitrogen and sulfur in the wastewater, greatly reducing the salinity of the wastewater to meet the discharge requirements, and recovering elemental sulfur, thereby achieving harmless and resourceful treatment of the wastewater;

[0012] (2) Compared with the existing physical treatment method of concentration and evaporation, the method provided by the present invention has simple process, small equipment investment, low energy consumption, convenient and controllable operation, and is easy to promote industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] 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:

[0014] Figure 1 It is a schematic diagram of the device used in Examples 1-4 of the present invention to treat high-sulfate and high-ammonia nitrogen wastewater.

[0015] Description of Reference Numerals

[0016] 1. Dosing and mixing device 2. Sedimentation tank

[0017] 3. Primary EGSB reactor 4. Secondary EGSB reactor

[0018] 5a, first peristaltic pump 5b, second peristaltic pump

[0019] 5c, third peristaltic pump 5d, fourth peristaltic 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-sulfate and high-ammonia nitrogen wastewater, the method comprising:

[0022] (1) subjecting the high-sulfate and high-ammonia nitrogen wastewater to chemical pre-precipitation treatment and neutralization treatment in sequence to obtain a sulfur-containing precipitation product and a first effluent;

[0023] (2) subjecting the first effluent to a sulfate reduction and denitrification reaction to obtain methane and a second effluent;

[0024] (3) subjecting the second effluent to a denitrification and desulfurization reaction to obtain nitrogen, elemental sulfur and purified water.

[0025] According to the present invention, the high-sulfate and high-ammonia nitrogen wastewater contains high concentrations of ammonia nitrogen and soluble sulfates, wherein the ammonia nitrogen refers to ammonia gas nitrogen soluble in water and ammonium ion nitrogen in an ionized state; the soluble sulfates may include but are not limited to sodium sulfate and / or potassium sulfate.

[0026] According to the present invention, the high-sulfate and high-ammonia nitrogen wastewater contains high-concentration sulfate, wherein the concentration of sulfate is 30-80 g / L, preferably 40-60 g / L.

[0027] In the present invention, the concentration of sulfate in the high-sulfate and high-ammonia nitrogen wastewater is measured by the amount of sulfate compounds. For example, in some embodiments, when the sulfate in the high-sulfate and high-ammonia nitrogen wastewater is Na2SO4 and / or K2SO4, the content of sulfate in the high-sulfate and high-ammonia nitrogen wastewater is measured by the concentration of Na2SO4 and / or K2SO4. The concentration of sulfate is measured according to the method specified in "Water Quality - Determination of Sulfate by Gravimetric Method" (GB / T 11899-1989).

[0028] According to the present invention, the high-sulfate and high-ammonia nitrogen wastewater contains a high concentration of ammonia nitrogen, wherein the concentration of ammonia nitrogen is 10-300 mg / L, preferably 40-80 mg / L.

[0029] 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).

[0030] According to the present invention, the high-sulfate and high-ammonia nitrogen wastewater may also contain refractory organic carbon-containing compounds, including but not limited to at least one of acetone, n-hexane, ethyl acetate, isobutanol and benzene series. Preferably, the high-sulfate and high-ammonia nitrogen wastewater has a COD value of 15-60 mg / L, preferably 40-60 g / L.

[0031] In the present invention, the COD value is determined according to the method specified in "Determination of Chemical Oxygen Demand of Water Quality - Rapid Digestion Spectrophotometry" (HJ / T399-2007).

[0032] According to the present invention, preferably, the high-sulfate and high-ammonia nitrogen wastewater can be flue gas desulfurization and denitrification wastewater from a power plant.

[0033] According to the present invention, in step (1) of the method, the high-sulfate and high-ammonia nitrogen wastewater is subjected to chemical pre-precipitation treatment, and a precipitant is used to react with the soluble sulfate contained therein to generate a sulfur-containing precipitation product, so as to achieve the removal of most of the SO4 contained in the high-sulfate and high-ammonia nitrogen wastewater. 2- Separate and remove.

[0034] According to the present invention, the precipitant used in the chemical pre-precipitation treatment contains Ca 2+ , preferably calcium hydroxide and / or calcium oxide. Wherein, calcium hydroxide can be in solid form or in the form of Ca(OH)2 solution, and the present invention has no particular limitation on this.

[0035] According to the present invention, the sulfur-containing precipitation product is mainly calcium sulfate.

[0036] According to the present invention, in step (1) of the method, a water-soluble base is generated during the chemical pre-precipitation treatment, so that the pH value of the wastewater obtained after the chemical pre-precipitation treatment increases to 10-14, and the pH value of the wastewater is adjusted to near neutral by performing the neutralization treatment.

[0037] According to the present invention, preferably, the neutralizing agent used in the neutralization treatment is an organic acid. Using an organic acid as a neutralizing agent can not only adjust the pH value of the wastewater, but also serve as an organic carbon source required for subsequent sulfate reduction denitrification reaction and denitrification desulfurization reaction by microbial method.

[0038] According to the present invention, preferably, the organic acid is selected from at least one of acetic acid, succinic acid, oxalic acid and citric acid, and more preferably acetic acid.

[0039] According to the present invention, in step (1) of the method, the amount of the precipitant is such that: the Ca in the precipitant is 2+ SO4 in the high sulfate and high ammonia nitrogen wastewater 2- The molar ratio is (0.9-1.3):1, preferably (1-1.2):1. The above preferred molar ratio can better take into account SO4 2- removal effect and the effect of supplementing the microbial matrix.

[0040] According to the present invention, in step (1) of the method, the amount of the neutralizing agent added is such that the pH value of the first effluent is 6.5-7.5. By controlling the pH value of the first effluent to be within the above range, it is beneficial to provide a more suitable pH environment for microorganisms in the subsequent sulfate reduction denitrification reaction and denitrification desulfurization reaction by microbial method, so as to better play the role of microorganisms.

[0041] According to the present invention, in step (1) of the method, the sulfate concentration in the first effluent is significantly reduced compared to the untreated high-sulfate and high-ammonia nitrogen wastewater. Preferably, the sulfate concentration in the first effluent is 12-16 g / L.

[0042] According to the present invention, in step (2) of the method, the first effluent is subjected to a biological sulfate reduction denitrification reaction (SR-DR), and under the action of anaerobic microorganisms, the SO4 contained in the first effluent is reduced to 2- Reduction into sulfide ions (S 2- ), a small amount of hydrogen sulfide, most of the ammonia nitrogen contained is oxidized and converted into NO3 - , NO2-, and the COD contained is converted into methane, carbon dioxide and water. Among them, the converted sulfur ion (S 2- )、NO3 - , NO2- and unconverted ammonia nitrogen exist in the second effluent, and methane can be utilized as a resource after being collected.

[0043] In the present invention, the anaerobic microorganisms used in the sulfate reduction and denitrification reaction include at least Raoultella, Megasphaera and Klebsiella.

[0044] According to the present invention, for the anaerobic microorganisms used in the sulfate reduction and denitrification reaction, based on the total amount of the anaerobic microorganisms, the biomass of Raoultella accounts for 5-40%, the biomass of Megasphaera accounts for 10-40%, and the biomass of Klebsiella accounts for 5-30%. Preferably, the biomass of Raoultella accounts for 8-40%, the biomass of Megasphaera accounts for 12-40%, and the biomass of Klebsiella accounts for 8-30%.

[0045] According to the present invention, the anaerobic microorganisms used in the sulfate reduction and denitrification reaction may include at least one of the genera Lactobacillus, Buttiauxella, Bifidobacterium, Simplicispira, Thauera and Shinella, in addition to Raoultella, Megasphaera and Klebsiella.

[0046] In the present invention, the biomass ratio refers to the ratio of the number of microorganisms of a certain genus in an anaerobic microorganism population to the number of all microorganisms in the anaerobic microorganism population.

[0047] In the present invention, preferably, the activated sludge used in the sulfate reduction denitrification reaction is at least one of activated sludge from a sewage plant, sludge cultured from seawater sludge, and high-salinity wastewater sludge.

[0048] 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 cultivated in the seawater sludge refers to the sludge obtained by taming 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.

[0049] According to the present invention, in step (2) of the method, the conditions for the sulfate reduction denitrification reaction include: temperature of 30-35°C; pH value of 6.5-7.5; reflux ratio of (25-35):1; hydraulic retention time of 20-30h.

[0050] According to the present invention, in step (3) of the method, the second effluent is subjected to a biological denitrification desulfurization reaction (DSR), and under the action of anaerobic microorganisms, the sulfur ions (S 2- ) is converted into elemental sulfur, and the ammonia nitrogen and NO3 - , NO2- is converted into nitrogen. Among them, elemental sulfur can be recycled after being collected, and nitrogen can be collected or discharged.

[0051] In the present invention, the anaerobic microorganisms used in the denitrification desulfurization reaction include at least Raoultella, Megasphaera and Klebsiella.

[0052] According to the present invention, for the anaerobic microorganisms used in the denitrification desulfurization reaction, based on the total amount of the anaerobic microorganisms, the biomass of Raoultella accounts for 15-50%, the biomass of Megasphaera accounts for 5-40%, and the biomass of Klebsiella accounts for 5-30%. Preferably, the biomass of Raoultella accounts for 20-40%, the biomass of Megasphaera accounts for 10-40%, and the biomass of Klebsiella accounts for 10-30%.

[0053] According to the present invention, the anaerobic microorganisms used in the denitrification desulfurization reaction may include at least one of the genera Lactobacillus, Buttiauxella, Bifidobacterium, Simplicispira, Thauera and Shinella, in addition to Raoultella, Megasphaera and Klebsiella.

[0054] In the present invention, preferably, the activated sludge used in the denitrification desulfurization reaction is at least one of activated sludge from a sewage plant, sludge cultured from seawater sludge, and high-salinity wastewater sludge.

[0055] According to the present invention, in step (3) of the method, the conditions of the denitrification desulfurization reaction include: temperature of 30-35°C; pH value of 6.5-7.5; reflux ratio of (25-35):1; hydraulic retention time of 20-30h.

[0056] According to the present invention, in the sulfate reduction denitrification reaction or the denitrification desulfurization reaction, a portion of the reactant-product system (i.e., the reflux liquid) will return and continue to participate in the reaction from which it came. In the above reaction conditions, the reflux ratio refers to the ratio of the flow rate of the reflux liquid to the flow rate of the effluent.

[0057] According to the present invention, in the above reaction conditions, the hydraulic retention time refers to the average time for the treated sewage to undergo sulfate reduction denitrification reaction or denitrification desulfurization reaction (ie, the average residence time of the treated sewage in the reactor).

[0058] According to the present invention, the anaerobic microorganisms used in the sulfate reduction denitrification reaction and the denitrification desulfurization reaction can be domesticated by conventional methods known in the art. The present invention does not particularly limit the process and conditions used for domestication.

[0059] According to the present invention, preferably, the sulfate reduction denitrification reaction and the denitrification desulfurization reaction are each independently carried out in a UASB (Upflow Anaerobic Sludge Blanket) reactor or an EGSB (Expanded Granular Sludge Bed) reactor. In order to obtain better reaction effect and treatment efficiency, it is further preferably carried out in an EGSB reactor.

[0060] In the present invention, the main components of the UASB reactor and EGSB reactor include a water inlet and outlet system, a reaction zone, a sedimentation zone, a three-phase separator, etc., and their specific composition and structure can be selected from those known in the prior art, and the present invention has no particular limitation on this.

[0061] According to the present invention, the method can efficiently remove sulfate and ammonia nitrogen contained in high-sulfate and high-ammonia nitrogen wastewater. After treatment, in the obtained purified water, the concentration of sulfate is reduced to 5-10g / L, the concentration of ammonia nitrogen is reduced to 2-6mg / L, and the COD value is 40-50mg / L.

[0062] The present invention will be described in detail below by way of examples. In the following examples and comparative examples,

[0063] High sulfate and high ammonia nitrogen wastewater: The wastewater was 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.

[0064] Table 1

[0065] Components content Sodium sulfate 40g / L Potassium sulfate 20g / L Ammonia nitrogen 43mg / L COD value 54mg / L

[0066] Note: In Table 1, the content of sodium sulfate 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.

[0067] The following examples 1-4 adopt Figure 1 The system shown is used to treat high-sulfate and high-ammonia nitrogen wastewater, and the system comprises a dosing and mixing device 1, a sedimentation tank 2, a primary EGSB reactor 3 and a secondary EGSB reactor 4 connected in sequence; wherein,

[0068] The primary EGSB reactor 3 and the secondary EGSB reactor 4 have the same structure and specifications. The two are connected in series. The parameters of a single reactor are as follows: the reactor is made of plexiglass, is equipped with a heating rod, and the reaction temperature in the reactor is controlled by a temperature controller; the reactor water inlet is introduced from the bottom by the first peristaltic pump 5a or the second peristaltic pump 5b, and a reflux port is provided near the three-phase separator, and part of the effluent is recycled back to the reactor from the reflux port by the third peristaltic pump 5c or the fourth peristaltic pump 5d; the total effective volume of a single reactor is 9.568L, and the total height is 200cm (wherein the inner diameter of the reaction zone is 6cm, the height is 150cm, and the volume is 4.0L; the inner diameter of the sedimentation zone is 15cm, the height is 35cm, and the volume is 5.568L); 8 sampling ports are provided on the reactor, and the spacing between each sampling port is 18cm.

[0069] The culture conditions of the anaerobic microorganisms used in the following examples are: temperature of 30-35°C and pH of 6.5-7.5.

[0070] Example 1

[0071] (1) High sulfate and high ammonia nitrogen wastewater is introduced into the dosing and mixing device 1, and calcium hydroxide solid (wherein the Ca 2+ SO4 in high sulfate and high ammonia nitrogen wastewater 2- The molar ratio is 1.1:1), after being fully and slowly stirred and mixed, the mixture is transferred to the sedimentation tank 2, and the produced calcium sulfate precipitate is removed by sedimentation separation;

[0072] After the above chemical pre-precipitation treatment, the pH value of the wastewater reached 13, and acetic acid was added for neutralization treatment to obtain the first effluent (pH value of 7.3, sulfate concentration of 16 g / L);

[0073] (2) The first effluent is introduced from the bottom of the primary EGSB reactor 3 through the first peristaltic pump 5a, enters the reaction zone from bottom to top and undergoes sulfate reduction and denitrification reaction (reaction temperature is 31°C, pH value is 7.1, reflux ratio is 30:1, hydraulic retention time is 24h);

[0074] The methane, carbon dioxide and a small amount of hydrogen sulfide obtained by the reaction are drawn out from the top of the first-stage EGSB reactor 3;

[0075] A portion of the effluent produced by the reaction is circulated back to the reactor from the reflux port near the three-phase separator of the first-stage EGSB reactor 3 through the third peristaltic pump 5c to continue the reaction, and the rest is drawn out from the top of the first-stage EGSB reactor 3 as the second effluent;

[0076] Among them, the anaerobic microorganisms used in the first-level EGSB reactor 3 are Raoultella, Megasphaera, Klebsiella, Lactobacillus, Buttiola, Bifidobacterium, Spirulina, Shennella and Tauer; based on the total amount of anaerobic microorganisms, the biomass of Raoultella accounts for 11.7%, the biomass of Megasphaera accounts for 13.1%, the biomass of Klebsiella accounts for 10.5%, the biomass of Lactobacillus accounts for 19.6%, the biomass of Buttiola accounts for 18.6%, the biomass of Bifidobacterium accounts for 13.4%, the biomass of Spirulina accounts for 5.9%, the biomass of Shennella accounts for 3.3%, and the biomass of Tauer accounts for 3.9%;

[0077] The activated sludge used is activated sludge from a sewage plant;

[0078] (3) The second effluent is introduced from the bottom of the secondary EGSB reactor 4 through the peristaltic second pump 5b, enters the reaction zone from bottom to top and undergoes a denitrification and desulfurization reaction (reaction temperature is 32°C, pH value is 6.9, reflux ratio is 31:1, hydraulic retention time is 24h);

[0079] The nitrogen obtained by the reaction is discharged from the top of the secondary EGSB reactor 4, and the elemental sulfur obtained is drawn out from the bottom of the secondary EGSB reactor 4 and recovered;

[0080] A portion of the water obtained by the reaction is circulated back to the reactor from the reflux port near the three-phase separator of the secondary EGSB reactor 4 through the fourth peristaltic pump 5d to continue the reaction, and the remaining portion is drawn out from the top of the secondary EGSB reactor 4 as purified water;

[0081] Among them, the anaerobic microorganisms used in the secondary EGSB reactor 4 are Raoultella, Megasphaera, Klebsiella, Lactobacillus, Buttiola, Bifidobacterium, Spirillum, Sheinella and Tauerella; based on the total amount of anaerobic microorganisms, the biomass of Raoultella accounts for 21%, the biomass of Megasphaera accounts for 14%, the biomass of Klebsiella accounts for 13%, the biomass of Lactobacillus accounts for 12.8%, the biomass of Buttiola accounts for 12.6%, the biomass of Bifidobacterium accounts for 12.3%, the biomass of Spirillum accounts for 11.7%, the biomass of Sheinella accounts for 2.3%, and the biomass of Tauerella accounts for 0.3%;

[0082] The activated sludge used is activated sludge from a sewage plant.

[0083] After treatment, the COD value of the purified water obtained, as well as the concentrations of sulfate and ammonia nitrogen contained therein are shown in Table 2.

[0084] Example 2

[0085] (1) High sulfate and high ammonia nitrogen wastewater is introduced into the dosing and mixing device 1, and calcium hydroxide solid (wherein the Ca 2+ SO4 in high sulfate and high ammonia nitrogen wastewater 2- The molar ratio is 1.2:1), after being fully and slowly stirred and mixed, the mixture is transferred to the sedimentation tank 2, and the produced calcium sulfate precipitate is removed by sedimentation separation;

[0086] After the above chemical pre-precipitation treatment, the pH value of the wastewater reached 13.5, and acetic acid was added for neutralization treatment to obtain the first effluent (pH value of 7.1, sulfate concentration of 14 g / L);

[0087] (2) The first effluent is introduced from the bottom of the primary EGSB reactor 3 through the first peristaltic pump 5a, enters the reaction zone from bottom to top and undergoes sulfate reduction and denitrification reaction (reaction temperature is 30.2°C, pH value is 7.3, reflux ratio is 28:1, hydraulic retention time is 28h);

[0088] The methane, carbon dioxide and hydrogen sulfide obtained by the reaction are drawn out from the top of the first-stage EGSB reactor 3;

[0089] A portion of the effluent produced by the reaction is circulated back to the reactor from the reflux port near the three-phase separator of the first-stage EGSB reactor 3 through the third peristaltic pump 5c to continue the reaction, and the rest is drawn out from the top of the first-stage EGSB reactor 3 as the second effluent;

[0090] Among them, the anaerobic microorganisms used in the first-level EGSB reactor 3 are Raoultella, Megasphaera, Klebsiella, Lactobacillus, Buttiola, Bifidobacterium, Spirillum, Sheinella and Tauerella; based on the total amount of anaerobic microorganisms, the biomass of Raoultella accounts for 9%, the biomass of Megasphaera accounts for 12%, the biomass of Klebsiella accounts for 11%, the biomass of Lactobacillus accounts for 16.2%, the biomass of Buttiola accounts for 16.4%, the biomass of Bifidobacterium accounts for 12.6%, the biomass of Spirillum accounts for 13.5%, the biomass of Sheinella accounts for 8%, and the biomass of Tauerella accounts for 1.3%;

[0091] The activated sludge used is activated sludge from a sewage plant;

[0092] (3) The second effluent is introduced from the bottom of the secondary EGSB reactor 4 through the second peristaltic pump 5b, enters the reaction zone from bottom to top and undergoes a denitrification and desulfurization reaction (reaction temperature is 30.2°C, pH value is 6.6, reflux ratio is 30:1, hydraulic retention time is 27h);

[0093] The nitrogen obtained by the reaction is discharged from the top of the secondary EGSB reactor 4, and the elemental sulfur obtained is drawn out from the bottom of the secondary EGSB reactor 4 and recovered;

[0094] A portion of the water obtained by the reaction is circulated back to the reactor from the reflux port near the three-phase separator of the secondary EGSB reactor 4 through the fourth peristaltic pump 5d to continue the reaction, and the remaining portion is drawn out from the top of the secondary EGSB reactor 4 as purified water;

[0095] Among them, the anaerobic microorganisms used in the secondary EGSB reactor 4 are Raoultella, Megasphaera, Klebsiella, Lactobacillus, Buttiola, Bifidobacterium, Spirillum, Sheinella and Tauerella; based on the total amount of anaerobic microorganisms, the biomass of Raoultella accounts for 24%, the biomass of Megasphaera accounts for 13%, the biomass of Klebsiella accounts for 11%, the biomass of Lactobacillus accounts for 13.6%, the biomass of Buttiola accounts for 15.1%, the biomass of Bifidobacterium accounts for 12.6%, the biomass of Spirillum accounts for 3.4%, the biomass of Sheinella accounts for 5.7%, and the biomass of Tauerella accounts for 1.6%;

[0096] The activated sludge used is activated sludge from a sewage plant.

[0097] After treatment, the COD value of the purified water obtained, as well as the concentrations of sulfate and ammonia nitrogen contained therein are shown in Table 2.

[0098] Example 3

[0099] (1) High sulfate and high ammonia nitrogen wastewater is introduced into the dosing and mixing device 1, and calcium hydroxide solid (wherein the Ca 2+ SO4 in high sulfate and high ammonia nitrogen wastewater 2- The molar ratio of the mixture is 1.25:1), and after being fully and slowly stirred and mixed, the mixture is transferred to the sedimentation tank 2, and the produced calcium sulfate precipitate is removed by sedimentation separation;

[0100] After the above chemical pre-precipitation treatment, the pH value of the wastewater reached 14, and acetic acid was added for neutralization treatment to obtain the first effluent (pH value of 7.3, sulfate concentration of 13.6 g / L);

[0101] (2) The first effluent is introduced from the bottom of the primary EGSB reactor 3 through the first peristaltic pump 5a, enters the reaction zone from bottom to top and undergoes sulfate reduction and denitrification reaction (reaction temperature is 34.6°C, pH value is 6.9, reflux ratio is 26:1, hydraulic retention time is 26h);

[0102] The methane, carbon dioxide and hydrogen sulfide obtained by the reaction are drawn out from the top of the first-stage EGSB reactor 3;

[0103] A portion of the effluent produced by the reaction is circulated back to the reactor from the reflux port near the three-phase separator of the first-stage EGSB reactor 3 through the third peristaltic pump 5c to continue the reaction, and the rest is drawn out from the top of the first-stage EGSB reactor 3 as the second effluent;

[0104] Among them, the anaerobic microorganisms used in the first-level EGSB reactor 3 are Raoultella, Megasphaera, Klebsiella, Lactobacillus, Buttiola, Bifidobacterium, Spirillum, Sheinella and Tauerella; based on the total amount of anaerobic microorganisms, the biomass of Raoultella accounts for 7.6%, the biomass of Megasphaera accounts for 11%, the biomass of Klebsiella accounts for 6.8%, the biomass of Lactobacillus accounts for 13.2%, the biomass of Buttiola accounts for 13.1%, the biomass of Bifidobacterium accounts for 12.3%, the biomass of Spirillum accounts for 14.9%, the biomass of Sheinella accounts for 11.6%, and the biomass of Tauerella accounts for 9.5%;

[0105] The activated sludge used is activated sludge from a sewage plant;

[0106] (3) The second effluent is introduced from the bottom of the secondary EGSB reactor 4 through the second peristaltic pump 5b, enters the reaction zone from bottom to top and undergoes a denitrification and desulfurization reaction (reaction temperature is 34.6°C, pH value is 6.9, reflux ratio is 29:1, hydraulic retention time is 26h);

[0107] The nitrogen obtained by the reaction is discharged from the top of the secondary EGSB reactor 4, and the elemental sulfur obtained is drawn out from the bottom of the secondary EGSB reactor 4 and recovered;

[0108] A portion of the water obtained by the reaction is circulated back to the reactor from the reflux port near the three-phase separator of the secondary EGSB reactor 4 through the fourth peristaltic pump 5d to continue the reaction, and the remaining portion is drawn out from the top of the secondary EGSB reactor 4 as purified water;

[0109] Among them, the anaerobic microorganisms used in the secondary EGSB reactor 4 are Raoultella, Megasphaera, Klebsiella, Lactobacillus, Buttiola, Bifidobacterium, Spirillum, Sheinella and Tauerella; based on the total amount of anaerobic microorganisms, the biomass of Raoultella accounts for 26%, the biomass of Megasphaera accounts for 6.8%, the biomass of Klebsiella accounts for 6%, the biomass of Lactobacillus accounts for 13.6%, the biomass of Buttiola accounts for 15.4%, the biomass of Bifidobacterium accounts for 12.9%, the biomass of Spirillum accounts for 13.5%, the biomass of Sheinella accounts for 4.3%, and the biomass of Tauerella accounts for 1.5%;

[0110] The activated sludge used is activated sludge from a sewage plant.

[0111] After treatment, the COD value of the purified water obtained, as well as the concentrations of sulfate and ammonia nitrogen contained therein are shown in Table 2.

[0112] Example 4

[0113] (1) High sulfate and high ammonia nitrogen wastewater is introduced into the dosing and mixing device 1, and calcium hydroxide solid (wherein the Ca 2+ SO4 in high sulfate and high ammonia nitrogen wastewater 2- The molar ratio is 1.1:1), after being fully and slowly stirred and mixed, the mixture is transferred to the sedimentation tank 2, and the produced calcium sulfate precipitate is removed by sedimentation separation;

[0114] After the above chemical pre-precipitation treatment, the pH value of the wastewater reached 13, and acetic acid was added for neutralization treatment to obtain the first effluent (pH value of 7.3, sulfate concentration of 16 g / L);

[0115] (2) The first effluent is introduced from the bottom of the primary EGSB reactor 3 through the first peristaltic pump 5a, enters the reaction zone from bottom to top and undergoes sulfate reduction and denitrification reaction (reaction temperature is 31°C, pH value is 7.1, reflux ratio is 30:1, hydraulic retention time is 24h);

[0116] The methane, carbon dioxide and a small amount of hydrogen sulfide obtained by the reaction are drawn out from the top of the first-stage EGSB reactor 3;

[0117] A portion of the effluent produced by the reaction is circulated back to the reactor from the reflux port near the three-phase separator of the first-stage EGSB reactor 3 through the third peristaltic pump 5c to continue the reaction, and the rest is drawn out from the top of the first-stage EGSB reactor 3 as the second effluent;

[0118] The anaerobic microorganisms used in the first-stage EGSB reactor 3 are Raoultella, Megasphaera and Klebsiella; based on the total amount of anaerobic microorganisms, the biomass of Raoultella accounts for 38%, the biomass of Megasphaera accounts for 35%, and the biomass of Klebsiella accounts for 27%;

[0119] The activated sludge used is activated sludge from a sewage plant;

[0120] (3) The second effluent is introduced from the bottom of the secondary EGSB reactor 4 through the second peristaltic pump 5b, enters the reaction zone from bottom to top and undergoes a denitrification and desulfurization reaction (reaction temperature is 32°C, pH value is 6.9, reflux ratio is 31:1, hydraulic retention time is 24h);

[0121] The nitrogen obtained by the reaction is discharged from the top of the secondary EGSB reactor 4, and the elemental sulfur obtained is drawn out from the bottom of the secondary EGSB reactor 4 and recovered;

[0122] A portion of the water obtained by the reaction is circulated back to the reactor from the reflux port near the three-phase separator of the secondary EGSB reactor 4 through the fourth peristaltic pump 5d to continue the reaction, and the remaining portion is drawn out from the top of the secondary EGSB reactor 4 as purified water;

[0123] The anaerobic microorganisms used in the secondary EGSB reactor 4 are Raoultella, Megasphaera and Klebsiella; based on the total amount of anaerobic microorganisms, the biomass of Raoultella accounts for 36%, the biomass of Megasphaera accounts for 37%, and the biomass of Klebsiella accounts for 27%;

[0124] The activated sludge used is activated sludge from a sewage plant.

[0125] After treatment, the COD value of the purified water obtained, as well as the concentrations of sulfate and ammonia nitrogen contained therein are shown in Table 2.

[0126] Comparative Example 1

[0127] The method of Example 1 is different in that no chemical pre-precipitation treatment is performed, but high-sulfate and high-ammonia nitrogen wastewater is used instead of the "first effluent" to perform steps (2) and (3) in sequence. Other conditions are the same as those of Example 1.

[0128] After treatment, the COD value of the purified water obtained, as well as the concentrations of sulfate and ammonia nitrogen contained therein are shown in Table 2.

[0129] Table 2

[0130]

[0131] Note: The sulfate concentration in Table 2 is based on the total concentration of Na2SO4 and K2SO4 in the purified water.

[0132] As can be seen from Table 2, the treatment method for high-sulfate and high-ammonia nitrogen wastewater provided by the present invention can make the sulfate concentration in the purified water lower than 10 / g / L, the ammonia nitrogen concentration lower than 6 / mg / L, and the COD value lower than 50, effectively achieving the simultaneous removal of carbon, nitrogen, and sulfur in the wastewater, greatly reducing the salinity of the wastewater, meeting the discharge requirements, and recovering elemental sulfur. In particular, Comparative Example 1 only uses biological methods. Due to the high sulfate and ammonia nitrogen concentrations in the wastewater, the osmotic pressure that the microorganisms need to tolerate is relatively large, the activity and treatment capacity of the microorganisms are limited, and the treatment effect is significantly worse than that of Examples 1-4.

[0133] 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-sulfate and high-ammonia nitrogen wastewater, characterized in that: The method includes: (1) subjecting the high-sulfate and high-ammonia nitrogen wastewater to chemical pre-precipitation treatment and neutralization treatment in sequence to obtain a sulfur-containing precipitation product and a first effluent; (2) subjecting the first effluent to a sulfate reduction and denitrification reaction to obtain methane and a second effluent; (3) subjecting the second effluent to a denitrification and desulfurization reaction to obtain nitrogen, elemental sulfur and purified water.

2. The method according to claim 1, wherein: In the high-sulfate and high-ammonia nitrogen wastewater, the concentration of sulfate is 30-80 g / L, preferably 40-60 g / L; Preferably, the concentration of ammonia nitrogen in the high-sulfate and high-ammonia nitrogen wastewater is 10-300 mg / L, more preferably 40-80 mg / L; Preferably, the COD value of the high-sulfate and high-ammonia nitrogen wastewater is 15-60 mg / L, and more preferably 40-60 g / L.

3. The method according to claim 1 or 2, wherein: In step (1), the precipitant used in the chemical pre-precipitation treatment is selected from calcium hydroxide and / or calcium oxide; Preferably, the neutralizing agent used in the neutralization treatment is an organic acid; Preferably, the organic acid is selected from at least one of acetic acid, succinic acid, oxalic acid and citric acid, more preferably acetic acid.

4. The method according to claim 3, wherein: In step (1), the amount of the precipitant is such that: 2+ SO4 in the high sulfate and high ammonia nitrogen wastewater 2- The molar ratio is (0.9-1.3):1, preferably (1-1.2):1; Preferably, the amount of the neutralizing agent added is such that the pH value of the first effluent is 6.5-7.5; Preferably, the concentration of sulfate in the first effluent is 12-16 g / L.

5. The method according to any one of claims 1 to 4, wherein: In step (2), the anaerobic microorganisms used in the sulfate reduction and denitrification reaction include at least Raoultella, Megasphaera and Klebsiella; Preferably, based on the total amount of the anaerobic microorganisms, the biomass of Raoultella accounts for 5-40%, the biomass of Megasphaera accounts for 10-40%, and the biomass of Klebsiella accounts for 5-30%; further preferably, the biomass of Raoultella accounts for 8-40%, the biomass of Megasphaera accounts for 12-40%, and the biomass of Klebsiella accounts for 8-30%; Preferably, the activated sludge used in the sulfate reduction denitrification reaction is selected from at least one of activated sludge from a sewage plant, sludge cultured from seawater sludge, and sludge from high-salinity wastewater.

6. The method according to any one of claims 1 to 5, wherein: In step (2), the conditions for the sulfate reduction denitrification reaction include: temperature of 30-35° C.; pH value of 6.5-7.5; reflux ratio of (25-35):1; and hydraulic retention time of 20-30 h.

7. The method according to any one of claims 1 to 6, wherein: In step (3), the anaerobic microorganisms used in the denitrification desulfurization reaction include at least Raoultella, Megasphaera and Klebsiella; Preferably, based on the total amount of the anaerobic microorganisms, the biomass of Raoultella accounts for 15-50%, the biomass of Megasphaera accounts for 5-40%, and the biomass of Klebsiella accounts for 5-30%; further preferably, the biomass of Raoultella accounts for 20-40%, the biomass of Megasphaera accounts for 10-40%, and the biomass of Klebsiella accounts for 10-30%; Preferably, the activated sludge used in the denitrification desulfurization reaction is at least one of activated sludge from a sewage plant, sludge cultivated from seawater sludge, and sludge from high-salinity wastewater.

8. The method according to any one of claims 1 to 7, wherein: In step (3), the conditions for the denitrification desulfurization reaction include: temperature of 30-35°C; pH value of 6.5-7.5; reflux ratio of (25-35):1; hydraulic retention time of 20-30h.

9. The method according to any one of claims 1 to 8, wherein: In the purified water, the concentration of sulfate is 5-10 g / L, the concentration of ammonia nitrogen is 2-6 mg / L, and the COD value is 40-50 mg / L.

10. The method according to any one of claims 1 to 9, wherein: The sulfate reduction denitrification reaction and the denitrification desulfurization reaction are each independently carried out in a UASB reactor or an EGSB reactor.

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