Method for treating combined-alkali wastewater

Abstract

The application provides a treatment method of combined alkali wastewater, comprising the following steps: (1) using landfill leachate to strengthen culture of short-cut nitrification sludge and anaerobic ammonia oxidation granular sludge; (2) mixing short-cut nitrification sludge and anaerobic ammonia oxidation granular sludge according to a set sludge dry weight ratio, and inoculating into a SBR reactor; (3) using combined alkali wastewater as influent, and adopting intermittent operation, and stopping reaction when the dissolved oxygen concentration continuously exceeds a set value; (4) adjusting the ratio of short-cut nitrification sludge and anaerobic ammonia oxidation granular sludge by controlling the sludge age, and realizing short-cut nitrification-anaerobic ammonia oxidation coupling; (5) mixing coal gasification furnace gas circulating water into the combined alkali wastewater, and realizing short-cut nitrification-anaerobic ammonia oxidation-sulfur autotrophic denitrification coupling after debugging operation; (6) after debugging and stabilizing, controlling the operation temperature, pH value and dissolved oxygen concentration, and realizing removal of ammonia nitrogen and total nitrogen in the combined alkali wastewater. The application realizes efficient and stable removal of ammonia nitrogen and total nitrogen in high-concentration combined alkali wastewater.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment and relates to a method for treating alkali wastewater. Background Art

[0002] Combined alkali wastewater is wastewater generated during the combined alkali production process. Its sources include carbonization tower tail gas washing wastewater (ammonia purification tower wastewater), heavy alkali calcination furnace gas condensation tower condensate, heavy alkali calcination furnace gas washing tower wastewater and vacuum filtration system ammonia purification tower wastewater, as well as ammonia II mud filter press plate frame washing water, equipment cleaning water, alkali filter machine car washing water, analytical testing water, centrifuge washing water, etc. The ammonia nitrogen concentration of this type of wastewater can usually reach more than 3000-5000 mg / L, Cl - The concentration can reach above 5000 mg / L, DDS can reach 40000μs / cm, with a certain concentration of elemental sulfur and sulfide, and almost no biodegradable COD. It is a typical high-salt, low carbon-nitrogen ratio and high ammonia nitrogen wastewater.

[0003] At present, technicians mainly use traditional biological denitrification processes based on nitrification and denitrification to treat high-concentration alkaline wastewater. First, it is diluted by adding clean water (or using low-concentration sewage in the park). The diluted wastewater is oxidized into nitrate nitrogen by the nitrification action of nitrifying bacteria under absolutely aerobic conditions. The nitrified wastewater is denitrified by adding external carbon sources under anoxic conditions, thereby achieving the removal of total nitrogen.

[0004] However, the above treatment methods have the following problems: (1) Low denitrification efficiency. The denitrification volumetric load of traditional nitrification and denitrification processes is usually less than 0.1 kgN / (m 3 ·d), the required retention time is long and the sewage station occupies a large area; (2) the system stability is poor, the wastewater not only has high ammonia nitrogen and total nitrogen concentrations, but also has high Cl - The concentration can reach more than 5000 mg / L. It is difficult for the traditional process microbial flora to achieve stable operation and is easily impacted. It usually needs to be diluted before treatment; (3) The amount of carbon source added is large. Since the wastewater is a typical low carbon-nitrogen ratio and high ammonia nitrogen wastewater, in order to achieve total nitrogen removal, a large amount of external carbon source must be added in the denitrification stage, and the operating cost is high; (4) The residual sludge output is large. Due to the large amount of external carbon source added in the denitrification stage, the amount of residual sludge increases significantly, thereby increasing the cost of residual sludge treatment and disposal; (5) The operating energy consumption is high. The nitrification process needs to be carried out under absolutely aerobic conditions. It takes 4.57g O2 to oxidize 1g of ammonia nitrogen into nitrate nitrogen. Therefore, a large amount of aeration energy will be consumed in the nitrification stage. In order to achieve denitrification, a large reflux ratio needs to be provided. Therefore, a large amount of reflux energy will be consumed in the denitrification stage.

[0005] It can be seen that how to provide a treatment method for combined alkali wastewater, improve denitrification efficiency and system stability, reduce carbon source addition and residual sludge production, and reduce operating energy consumption and treatment costs has become an urgent problem that technical personnel in this field need to solve. Summary of the Invention

[0006] The object of the present invention is to provide a method for treating soda-soaked wastewater, which achieves efficient and stable removal of ammonia nitrogen and total nitrogen in high-concentration soda-soaked wastewater, improves denitrification efficiency and system stability, reduces carbon source addition and residual sludge production, reduces operating energy consumption and treatment costs, and is conducive to large-scale promotion and application.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] The present invention provides a method for treating alkali wastewater, which comprises the following steps:

[0009] (1) Using landfill leachate to intensify the cultivation of short-range nitrification sludge and anaerobic ammonium oxidation granular sludge;

[0010] (2) mixing the short-cut nitrification sludge and the anaerobic ammonium oxidation granular sludge according to the set sludge dry weight ratio, and inoculating the resulting mixed sludge into the SBR reactor;

[0011] (3) The SBR reactor uses alkali wastewater as influent and operates intermittently. Each operating cycle consists of four steps: influent, reaction, sedimentation, and drainage. The reaction is stopped when the dissolved oxygen concentration in the system is continuously higher than the set value.

[0012] (4) By controlling the sludge age, the ratio of short-cut nitrification sludge to anaerobic ammonium oxidation granular sludge is adjusted to achieve short-cut nitrification-anaerobic ammonium oxidation coupling in the SBR reactor;

[0013] (5) Mixing the coal gasification furnace gasification circulating water with the alkali wastewater, and using the elemental sulfur and sulfide in the gasification circulating gas to cultivate sulfur autotrophic denitrifying bacteria, after commissioning and operation, the coupling of short-cut nitrification-anaerobic ammonium oxidation-sulfur autotrophic denitrification is achieved in the SBR reactor;

[0014] (6) After debugging and stabilization, control the operating temperature, pH value and dissolved oxygen concentration, and remove ammonia nitrogen and total nitrogen from the soda ash wastewater.

[0015] The ammonia nitrogen concentration of the soda ash wastewater is 3000-5000 mg / L, for example, 3000 mg / L, 3200 mg / L, 3400 mg / L, 3600 mg / L, 3800 mg / L, 4000 mg / L, 4200 mg / L, 4400 mg / L, 4600 mg / L, 4800 mg / L or 5000 mg / L.- The concentration is ≥5000 mg / L, for example, it can be 5000 mg / L, 5200 mg / L, 5400 mg / L, 5600 mg / L, 5800 mg / L, 6000 mg / L, 6200 mg / L, 6400 mg / L, 6600 mg / L, 6800 mg / L or 7000 mg / L; the conductivity is ≥40000 μs / cm, for example, it can be 40000 μs / cm, 42000 μs / cm, 44000 μs / cm, 46000 μs / cm, 48000 μs / cm, 50000 μs / cm, 52000 μs / cm, 54000 μs / cm, 56000 μs / cm, 58000 μs / cm or 60000 μs / cm, but is not limited to the listed values, and other unlisted values ​​within this numerical range are equally applicable.

[0016] Preferably, the enhanced culture time of the short-range nitrification sludge and anaerobic ammonium oxidation granular sludge in step (1) is ≥100d, for example, it can be 100d, 105d, 110d, 115d, 120d, 125d, 130d, 135d, 140d, 145d or 150d, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0017] The present invention uses landfill leachate with complex components and high biological toxicity to carry out intensive cultivation of short-range nitrification sludge and anaerobic ammonia oxidation sludge for more than 100 days, effectively improving the microbial activity of ammonia nitrogen concentration and Cl - Concentration and conductivity tolerance.

[0018] Preferably, the set value of the sludge dry weight ratio in step (2) is 1:(3-4), for example, it can be 1:3, 1:3.1, 1:3.2, 1:3.3, 1:3.4, 1:3.5, 1:3.6, 1:3.7, 1:3.8, 1:3.9 or 1:4, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0019] Preferably, the sludge concentration in the SBR reactor after inoculation of the mixed sludge in step (2) is 6000-10000 mg / L, for example, it can be 6000 mg / L, 6500 mg / L, 7000 mg / L, 7500 mg / L, 8000 mg / L, 8500 mg / L, 9000 mg / L, 9500 mg / L or 10000 mg / L, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0020] Preferably, the water filling ratio of the inlet water in step (3) is (6-10):100, for example, it can be 6:100, 6.5:100, 7:100, 7.5:100, 8:100, 8.5:100, 9:100, 9.5:100 or 10:100, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0021] Preferably, the water intake and drainage in step (3) are performed manually.

[0022] Preferably, the SBR reactor in step (3) is operated under aeration conditions.

[0023] Preferably, the set value of the dissolved oxygen concentration in step (3) is 1.5 mg / L.

[0024] Preferably, the sludge age of the short-range nitrification sludge in step (4) is controlled to be 20-40d, for example, it can be 20d, 22d, 24d, 26d, 28d, 30d, 32d, 34d, 36d, 38d or 40d, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0025] Preferably, the sludge age of the anaerobic ammonium oxidation granular sludge in step (4) is controlled to be 80-120d, for example, it can be 80d, 85d, 90d, 95d, 100d, 105d, 110d, 115d or 120d, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0026] Preferably, the mixing ratio of the gasification furnace gasification circulating water in the alkali wastewater in step (5) is 5-8wt%, for example, it can be 5wt%, 5.5wt%, 6wt%, 6.5wt%, 7wt%, 7.5wt% or 8wt%, but it is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0027] Preferably, the debugging operation time in step (5) is 8-12 days, for example, it can be 8 days, 8.5 days, 9 days, 9.5 days, 10 days, 10.5 days, 11 days, 11.5 days or 12 days, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] Preferably, the operating temperature in step (6) is 20-35°C, for example, it can be 20°C, 22°C, 24°C, 26°C, 28°C, 30°C, 32°C, 34°C or 35°C, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0029] Preferably, the pH value in step (6) is 7.0-8.5, for example, 7.0, 7.2, 7.4, 7.6, 7.8, 8.0, 8.2, 8.4 or 8.5, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0030] Preferably, the dissolved oxygen concentration in step (6) is ≤0.5 mg / L, for example, it can be 0.05 mg / L, 0.1 mg / L, 0.15 mg / L, 0.2 mg / L, 0.25 mg / L, 0.3 mg / L, 0.35 mg / L, 0.4 mg / L, 0.45 mg / L or 0.5 mg / L, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0031] As a preferred technical solution of the present invention, the processing method includes the following steps:

[0032] (1) Using landfill leachate to intensify the cultivation of short-range nitrification sludge and anaerobic ammonium oxidation granular sludge, and the intensified cultivation time is ≥100 days;

[0033] (2) Short-cut nitrification sludge and anaerobic ammonium oxidation granular sludge were mixed at a sludge dry weight ratio of 1:(3-4), and the resulting mixed sludge was inoculated into a SBR reactor. After inoculation, the sludge concentration in the SBR reactor was 6000-10000 mg / L;

[0034] (3) Under aeration conditions, the SBR reactor uses the soda ash wastewater as the inlet water, and the water filling ratio is set to (6-10):100. It adopts intermittent operation, and each operation cycle consists of four processes: water inlet, reaction, precipitation and drainage. The water inlet and drainage are performed manually. The reaction is stopped when the dissolved oxygen concentration in the system is continuously higher than 1.5 mg / L.

[0035] (4) The sludge age of the shortcut nitrification sludge is controlled to 20-40 days, and the sludge age of the anaerobic ammonium oxidation granular sludge is controlled to 80-120 days to adjust the ratio of the shortcut nitrification sludge and the anaerobic ammonium oxidation granular sludge, and realize the coupling of shortcut nitrification and anaerobic ammonium oxidation in the SBR reactor;

[0036] (5) Mixing 5-8 wt% of gasification circulating water from a coal gasifier into the soda ash wastewater, cultivating sulfur autotrophic denitrifying bacteria using elemental sulfur and sulfide in the gasification circulating gas, and achieving the coupling of short-cut nitrification-anaerobic ammonium oxidation-sulfur autotrophic denitrification in a SBR reactor after 8-12 days of commissioning and operation;

[0037] (6) After the debugging is stable, the operating temperature is controlled at 20-35℃, the pH value is 7.0-8.5, and the dissolved oxygen concentration is ≤0.5mg / L, and the ammonia nitrogen and total nitrogen are removed from the soda ash wastewater.

[0038] The ammonia nitrogen concentration of the soda ash wastewater is 3000-5000 mg / L, and the Cl - Concentration ≥5000mg / L, conductivity ≥40000μs / cm.

[0039] The numerical range described in the present invention includes not only the point values ​​listed above, but also any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) The denitrification efficiency is high, and the denitrification volumetric load of the coupled process of short-range nitrification-anaerobic ammonium oxidation-sulfur autotrophic denitrification can be stably higher than 0.8kgN / (m 3 d) The required residence time is short, which can save more than 80% of the floor space and effective pool volume compared to traditional nitrification and denitrification processes, thereby significantly reducing civil engineering and investment costs;

[0042] (2) The system has high stability. The short-term nitrification sludge and anaerobic ammonium oxidation sludge cultivated with landfill leachate for a long time can effectively treat high concentrations of ammonia nitrogen and high concentrations of Cl - It has good tolerance to high concentration TDS and can withstand high concentration alkali wastewater with ammonia nitrogen concentration of 3000-5000 mg / L, Cl - The water quality conditions are as follows: concentration of 5000mg / L or above, conductivity of 40000μs / cm or above, the system has good stability, is not easily affected by shock, and the wastewater can be directly treated without dilution;

[0043] (3) Substantially save external carbon source. The anaerobic ammonia oxidation denitrification process uses ammonia nitrogen as an electron donor and nitrite nitrogen as an electron acceptor. No external carbon source is required. In this stage, a total nitrogen removal rate of more than 90% is achieved under fully autotrophic conditions. The remaining small portion (less than 10%) of residual nitrate nitrogen can be treated to meet the standards by denitrification. Compared with the traditional nitrification and denitrification process, more than 90% of the external carbon source can be saved, thereby significantly reducing the cost of adding the carbon source.

[0044] (4) The amount of excess sludge is small. Short-term nitrifying bacteria, anaerobic ammonia oxidizing bacteria and sulfur autotrophic denitrifying bacteria are all chemoautotrophic microorganisms with low sludge yield coefficients, which greatly reduces the amount of excess sludge and effectively reduces the cost of excess sludge treatment and disposal.

[0045] (5) Low operating energy consumption. During the treatment process, only 55% of the ammonia nitrogen is oxidized into nitrite nitrogen under aerobic conditions. It only takes 3.42g of O2 to oxidize 1g of ammonia nitrogen into nitrite nitrogen. The remaining 45% of the ammonia nitrogen is oxidized into nitrogen gas through nitrite nitrogen under anoxic conditions, which can save 57% of the aeration energy consumption. In addition, because the process does not require denitrification through reflux, it can save 100% of the reflux energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a graph showing the change trend of the ammonia nitrogen concentration in the inlet and outlet water over time in the treatment method provided in Example 1;

[0047] Figure 2 This is a graph showing the change in total nitrogen concentration over time in the treatment method provided in Example 1;

[0048] Figure 3 This is a graph showing the change trend of total nitrogen removal rate over time in the treatment method provided in Example 1;

[0049] Figure 4 This is a graph showing the change trend of ammonia nitrogen concentration in the inlet and outlet water over time in the treatment method provided in Example 2;

[0050] Figure 5 This is a graph showing the change in total nitrogen concentration over time in the treatment method provided in Example 2;

[0051] Figure 6 This is a graph showing the total nitrogen removal rate changing over time in the treatment method provided in Example 2. DETAILED DESCRIPTION

[0052] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0053] Example 1

[0054] This embodiment provides a method for treating alkali wastewater under working condition 1, comprising the following steps:

[0055] (1) Landfill leachate was used to intensify the cultivation of short-range nitrification sludge and anaerobic ammonium oxidation granular sludge, and the intensified cultivation time was 120 days;

[0056] (2) Short-cut nitrification sludge and anaerobic ammonium oxidation granular sludge were mixed at a sludge dry weight ratio of 1:3, and the resulting mixed sludge was inoculated into a SBR reactor. After inoculation, the sludge concentration in the SBR reactor was 8000 mg / L;

[0057] (3) Under aeration conditions, the SBR reactor (the main body is a tendon plastic barrel with a height of 1315 mm, a diameter of 1070 mm, and an effective volume of 1000 L) uses the soda ash wastewater as the inlet water, sets the water filling ratio to 8:100, and operates at room temperature. The aeration volume is controlled by a rotor flowmeter and intermittent operation is adopted. Each operation cycle consists of four processes: water inlet, reaction, precipitation, and drainage. Water inlet and drainage are carried out manually. The reaction endpoint is indicated by the dissolved oxygen concentration in the system. The reaction is stopped when the dissolved oxygen concentration in the system rises rapidly and remains higher than 1.5 mg / L.

[0058] (4) The sludge age of the shortcut nitrification sludge was controlled to 30 days, and the sludge age of the anaerobic ammonium oxidation granular sludge was controlled to 100 days to adjust the ratio of the shortcut nitrification sludge and the anaerobic ammonium oxidation granular sludge, and to achieve the coupling of shortcut nitrification and anaerobic ammonium oxidation in the SBR reactor;

[0059] (5) 6 wt% of gasification furnace gasification circulating water was mixed into the alkali wastewater, and the elemental sulfur and sulfide in the gasification circulating gas were used to cultivate sulfur autotrophic denitrifying bacteria. After 10 days of commissioning, the coupling of short-range nitrification-anaerobic ammonia oxidation-sulfur autotrophic denitrification was achieved in the SBR reactor. The ammonia nitrogen concentration of the effluent was stabilized within 2-5 mg / L, and the total nitrogen volumetric load removal rate reached 0.9 kgN / (m 3 d) The total nitrogen removal rate is over 90%;

[0060] (6) After the debugging is stable, the operating temperature is controlled at 30±5℃, the pH value is 7.5±0.5, and the dissolved oxygen concentration is ≤0.5mg / L. The ammonia nitrogen and total nitrogen of the soda ash wastewater are removed. The stable operation is continued for 30 days, and the data is recorded and analyzed.

[0061] In this embodiment, the trend of ammonia nitrogen concentration in the inlet and outlet water over time is shown in Figure 1 The trend of total nitrogen concentration in inlet and outlet water over time is shown in Figure 2 The trend of total nitrogen removal rate over time is shown in Figure 3 .

[0062] Combine Figure 1-3 It can be seen that the treatment method provided in this embodiment can achieve a total nitrogen removal rate of more than 90% for the soda ash wastewater without the participation of an external carbon source.

[0063] Example 2

[0064] This embodiment provides a method for treating alkali wastewater under working condition 2, comprising the following steps:

[0065] (1) Landfill leachate was used to intensify the cultivation of short-range nitrification sludge and anaerobic ammonium oxidation granular sludge, and the intensified cultivation time was 150 days;

[0066] (2) Short-cut nitrification sludge and anaerobic ammonium oxidation granular sludge were mixed at a sludge dry weight ratio of 1:3, and the resulting mixed sludge was inoculated into a SBR reactor. After inoculation, the sludge concentration in the SBR reactor was 9000 mg / L;

[0067] (3) Under aeration conditions, the SBR reactor (the main body is an acrylic reactor with a height of 990 mm, a diameter of 525 mm, and an effective volume of 200 L) uses the soda ash wastewater as the inlet water, sets the water filling ratio to 10:100, and operates at room temperature. The aeration volume is controlled by a rotor flowmeter and intermittent operation is adopted. Each operation cycle consists of four processes: water inlet, reaction, precipitation, and drainage. Water inlet and drainage are carried out manually. The reaction endpoint is indicated by the dissolved oxygen concentration in the system. The reaction is stopped when the dissolved oxygen concentration in the system rises rapidly and remains higher than 1.5 mg / L.

[0068] (4) The sludge age of the shortcut nitrification sludge was controlled to 20 days, and the sludge age of the anaerobic ammonium oxidation granular sludge was controlled to 80 days to adjust the ratio of the shortcut nitrification sludge and the anaerobic ammonium oxidation granular sludge, and to achieve the coupling of shortcut nitrification and anaerobic ammonium oxidation in the SBR reactor;

[0069] (5) 8 wt% of gasification furnace circulating water was mixed into the alkali wastewater, and the elemental sulfur and sulfide in the circulating gas were used to cultivate sulfur autotrophic denitrifying bacteria. After 9 days of commissioning, the coupling of short-range nitrification-anaerobic ammonia oxidation-sulfur autotrophic denitrification was achieved in the SBR reactor. The ammonia nitrogen concentration of the effluent was stabilized within 1-6 mg / L, and the total nitrogen volumetric load removal rate reached 1.0 kgN / (m 3 d) The total nitrogen removal rate is over 91%;

[0070] (6) After the debugging is stable, the operating temperature is controlled at 30±5℃, the pH value is 7.5±0.5, and the dissolved oxygen concentration is ≤0.5mg / L. The ammonia nitrogen and total nitrogen of the soda ash wastewater are removed. The stable operation is continued for 22 days, and the data is recorded and analyzed.

[0071] In this embodiment, the trend of ammonia nitrogen concentration in the inlet and outlet water over time is shown in Figure 4 The trend of total nitrogen concentration in inlet and outlet water over time is shown in Figure 5 The trend of total nitrogen removal rate over time is shown in Figure 6 .

[0072] Combine Figure 4-6 It can be seen that the treatment method provided in this embodiment can achieve a total nitrogen removal rate of more than 91% for the soda ash wastewater without the participation of an external carbon source.

[0073] It can be seen that the treatment methods provided in Examples 1 and 2 have the following beneficial effects:

[0074] (1) The denitrification efficiency is high. The denitrification volumetric load of the coupled process of short-range nitrification-anaerobic ammonium oxidation-sulfur autotrophic denitrification can be stably higher than 0.8 kgN / (m 3 ·d) and 1.0kgN / (m 3 d) The required residence time is short, which can save more than 80% of the floor space and effective pool volume compared to traditional nitrification and denitrification processes, thereby significantly reducing civil engineering and investment costs;

[0075] (2) The system is highly stable. The short-term nitrification sludge and anaerobic ammonium oxidation sludge cultivated with landfill leachate for a long time (120 days and 150 days) can effectively treat high concentrations of ammonia nitrogen and Cl - It has good tolerance to high concentration TDS and can withstand high concentration alkali wastewater with ammonia nitrogen concentration of 3000-5000 mg / L, Cl - The water quality conditions are as follows: concentration of 5000mg / L or above, conductivity of 40000μs / cm or above, the system has good stability, is not easily affected by shock, and the wastewater can be directly treated without dilution;

[0076] (3) Substantially saves external carbon source. The anaerobic ammonia oxidation denitrification process uses ammonia nitrogen as an electron donor and nitrite nitrogen as an electron acceptor, without the need for external carbon source participation. In this stage, Examples 1 and 2 respectively achieve total nitrogen removal rates of 90% and 91% or more under fully autotrophic conditions. The remaining small portion (less than 10%) of residual nitrate nitrogen can be treated to meet the standards by supplementing denitrification. Compared with the traditional nitrification and denitrification process, more than 90% of the external carbon source can be saved, thereby significantly reducing the cost of adding the carbon source.

[0077] (4) The amount of excess sludge is small. Short-term nitrifying bacteria, anaerobic ammonia oxidizing bacteria and sulfur autotrophic denitrifying bacteria are all chemoautotrophic microorganisms with low sludge yield coefficients, which greatly reduces the amount of excess sludge and effectively reduces the cost of excess sludge treatment and disposal.

[0078] (5) Low operating energy consumption. During the treatment process, only 55% of the ammonia nitrogen is oxidized into nitrite nitrogen under aerobic conditions. It only takes 3.42g of O2 to oxidize 1g of ammonia nitrogen into nitrite nitrogen. The remaining 45% of the ammonia nitrogen is oxidized into nitrogen gas through nitrite nitrogen under anoxic conditions, which can save 57% of the aeration energy consumption. In addition, because the process does not require denitrification through reflux, it can save 100% of the reflux energy consumption.

[0079] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for treating alkali wastewater, characterized in that: The processing method comprises the following steps: (1) Using landfill leachate to intensify the cultivation of short-cut nitrification sludge and anaerobic ammonium oxidation granular sludge; (2) Mixing the short-cut nitrification sludge and the anaerobic ammonium oxidation granular sludge according to the set sludge dry weight ratio, and inoculating the resulting mixed sludge into the SBR reactor; (3) The SBR reactor uses alkali wastewater as influent and operates intermittently. Each operating cycle consists of four processes: water inlet, reaction, sedimentation, and drainage. The reaction is stopped when the dissolved oxygen concentration in the system is continuously higher than the set value. (4) The sludge age of the short-cut nitrification sludge is controlled to 20-40 days, and the sludge age of the anaerobic ammonium oxidation granular sludge is controlled to 80-120 days to adjust the ratio of the short-cut nitrification sludge and the anaerobic ammonium oxidation granular sludge, and realize the coupling of short-cut nitrification and anaerobic ammonium oxidation in the SBR reactor; (5) 5-8 wt% of gasification furnace circulating water is mixed into the alkali wastewater, and the elemental sulfur and sulfide in the gasification circulating gas are used to cultivate sulfur autotrophic denitrifying bacteria. After 8-12 days of commissioning, the coupling of short-cut nitrification-anaerobic ammonium oxidation-sulfur autotrophic denitrification is achieved in the SBR reactor; (6) After the debugging is stable, the operating temperature is controlled at 20-35℃, the pH value is 7.0-8.5, and the dissolved oxygen concentration is ≤0.5mg / L, and the ammonia nitrogen and total nitrogen are removed from the soda ash wastewater; The ammonia nitrogen concentration of the soda ash wastewater is 3000-5000 mg / L, and the Cl - Concentration ≥5000mg / L, conductivity ≥40000μs / cm.

2. The processing method according to claim 1, characterized in that The intensive culture time of the short-cut nitrification sludge and anaerobic ammonium oxidation granular sludge in step (1) is ≥100 days.

3. The processing method according to claim 1, characterized in that The set value of the sludge dry weight ratio in step (2) is 1:(3-4).

4. The processing method according to claim 1, characterized in that The sludge concentration in the SBR reactor after the mixed sludge inoculation in step (2) is 6000-10000 mg / L.

5. The processing method according to claim 1, characterized in that The filling ratio of the inlet water in step (3) is (6-10):

100.

6. The processing method according to claim 1, characterized in that The water intake and drainage in step (3) are performed manually.

7. The processing method according to claim 1, characterized in that The SBR reactor in step (3) is operated under aeration conditions.

8. The processing method according to claim 1, characterized in that The set value of the dissolved oxygen concentration in step (3) is 1.5 mg / L.

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