A method for biochemical treatment and synchronous salt separation of high-salt pyrimidine ring industrial wastewater

Abstract

The application discloses a biochemical treatment and salt synchronous separation method of high-salt pyrimidine ring industrial wastewater. The high-salt pyrimidine ring industrial wastewater is introduced into a biochemical reaction system, and the biochemical reaction system at least comprises a biological adsorption induction unit, an inorganic salt interception and organic matter biological degradation cooperation unit and a denitrification unit. In the inorganic salt interception and organic matter biological degradation cooperation unit, sodium sulfate crystals / particles in the wastewater are physically intercepted by activated sludge flocs and enriched in the inside of the sludge flocs, and meanwhile, the activated sludge biodegrades organic matters in the wastewater. The sodium sulfate intercepted and enriched in the inside of the sludge flocs is discharged from the system with the remaining sludge, so that the synchronous separation of the sodium sulfate from the wastewater is realized. The biochemical treatment of the organic pollutants in the high-salt pyrimidine ring wastewater and the synchronous separation of the salt are completed in the same biochemical system, and no special salt removal unit such as a membrane separation unit, an evaporation crystallization unit or other units is arranged, so that the process flow is short, the equipment investment is low, and the operation cost is obviously reduced.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology for high concentration, high salinity, and high organic nitrogen factors, and specifically relates to a biochemical treatment and simultaneous salt separation method for high-salt pyrimidine ring industrial wastewater. Background Technology

[0002] With the rapid development of my country's chemical and pharmaceutical industries, a large amount of industrial wastewater containing compounds with pyrimidine ring structures has been generated. This type of wastewater not only has a high COD... cr High concentrations of ammonia nitrogen and total nitrogen, often accompanied by high concentrations of inorganic salts (such as sodium sulfate), make it a typical "three-high" wastewater characterized by high concentration, high salinity, and high organic nitrogen factors, which is extremely difficult to treat.

[0003] Currently, for high-salinity pyrimidine ring industrial wastewater containing sodium sulfate, conventional treatment processes typically employ a two-stage approach: "desalination pretreatment + biological treatment." First, sodium sulfate is removed from the wastewater using physicochemical methods such as membrane separation and evaporation crystallization. Then, the low-salinity wastewater is fed into a biological system for the biodegradation of organic matter. However, this technical approach has the following prominent problems:

[0004] (1) Sodium sulfate is difficult to biodegrade, and traditional desalination units are costly: Sodium sulfate, as an inorganic salt, is difficult to degrade through biological pathways, especially when it is used in high-concentration, high-salt pyrimidine ring industrial wastewater, and must be separated and removed from the aqueous phase. Existing desalination methods mainly rely on membrane separation and evaporation crystallization technologies. However, such equipment requires large investments and consumes a lot of energy. In actual operation, due to the large amount of organic matter and suspended solids in the wastewater, serious problems such as viscous feed liquid and blockage of the evaporator often occur, leading to frequent equipment shutdowns for cleaning, which seriously affects treatment efficiency and system stability.

[0005] (2) High salt environment inhibits microbial activity and results in low biochemical treatment efficiency: Sodium sulfate residue in wastewater creates a high osmotic pressure environment, which has a strong salt stress effect on activated sludge microorganisms, inhibiting their metabolic activity and leading to COD. cr The removal efficiency of ammonia nitrogen and total nitrogen decreases significantly, and may even cause the biological system to collapse. As a result, traditional processes have to invest heavily in desalination units to reduce the salt content to within the range that microorganisms can tolerate before biological treatment can proceed.

[0006] (3) Existing activated sludge processes lack a synergistic mechanism for the simultaneous removal of inorganic salts: Existing technologies, such as patent CN103508552A, disclose a method for maintaining particulate matter concentration in an activated sludge treatment system. This method maintains particulate matter concentration by controlling the ash content of the discharged residual sludge to be lower than the average ash content of the system sludge. The starting point of this technical solution is still to minimize the discharge of inorganic matter (ash) to avoid organic matter loss, without considering the use of activated sludge flocs to retain inorganic salts and achieve simultaneous salt removal. For high-salt pyrimidine ring wastewater containing sodium sulfate, this type of method cannot solve the problem of inorganic salt accumulation in the system. Salt is discharged with the effluent or continues to accumulate in the system, and cannot be effectively removed from the aqueous phase.

[0007] In summary, existing technologies for treating high-salt pyrimidine ring industrial wastewater suffer from several technical challenges, including the disconnect between desalination and biochemical treatment, easy clogging of desalination units, and high operating costs. There is an urgent need to develop a novel process that can simultaneously separate and remove sodium sulfate from the aqueous phase during biochemical treatment. Based on the current situation, a method for the simultaneous biochemical treatment and salt separation of high-salt pyrimidine ring industrial wastewater is proposed. Summary of the Invention

[0008] The purpose of this invention is to provide a method for the biochemical treatment and simultaneous salt separation of high-salt pyrimidine ring industrial wastewater, thereby solving the problems mentioned in the background art. The method for the biochemical treatment and simultaneous salt separation of high-salt pyrimidine ring industrial wastewater provided by this invention achieves a combination of a bio-adsorption induction unit, an inorganic salt retention and biodegradation synergistic unit, and a biological denitrification unit by constructing interconnected units with different specific functions, thus simultaneously reducing the influent COD. cr Under conditions where COD ≤10000mg / L, ammonia nitrogen ≤500mg / L, total nitrogen ≤1000mg / L, TDS ≤30000mg / L, and sulfate ≤20000mg / L, the effluent COD after biological treatment... cr Removal efficiency of ≤500mg / L, ammonia nitrogen ≤20mg / L, total nitrogen ≤50mg / L, TDS ≤14000mg / L, and sulfate ≤8000mg / L.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a method for biochemical treatment and simultaneous salt separation of high-salt pyrimidine ring industrial wastewater, comprising the following steps:

[0010] S1. Introduce high-salt pyrimidine ring industrial wastewater into a biochemical reaction system. The biochemical reaction system includes at least a bio-adsorption induction unit, an inorganic salt interception and organic matter biodegradation synergistic unit, and a denitrification unit.

[0011] S2. In the synergistic unit of inorganic salt interception and organic matter biodegradation, sodium sulfate crystals / particles in the wastewater are physically intercepted by activated sludge flocs and enriched inside the sludge flocs, while the activated sludge biodegrades the organic matter in the wastewater.

[0012] S3. Sodium sulfate that is trapped and enriched inside the sludge flocs is discharged from the system along with the remaining sludge, realizing the simultaneous separation of sodium sulfate from wastewater.

[0013] The biosorption induction unit comprises a hydrolysis acidification tank and an anaerobic tank connected sequentially along the water flow direction. High-salinity industrial wastewater containing pyrimidine rings is introduced into the biosorption section containing activated sludge. Operating under low dissolved oxygen conditions, the dissolved oxygen in the hydrolysis acidification section is controlled at 0.2-0.5 mg / L, and the dissolved oxygen in the anaerobic section is controlled at ≤0.2 mg / L. This induces the activated sludge to secrete extracellular polymeric substances (EPS). Through the electrostatic adsorption and complexation of EPS, metal cations in the wastewater are selectively enriched, forming an activated sludge mixed liquor loaded with metal cations.

[0014] Furthermore, in this invention, the synergistic unit for inorganic salt retention and organic biodegradation includes a biological decarbonization tank along the water flow direction. This unit raises the system pH to 7.8-8.5 through high-intensity aeration, triggering in-situ chemical precipitation reactions between metal cations adsorbed by extracellular polymers and anions such as sulfate in the wastewater within and on the surface of the activated sludge flocs. This reduces the effective salinity of the floc microenvironment. In a specific high-salt pyrimidine ring wastewater biochemical system, sodium sulfate is enriched from the aqueous phase to the sludge phase through microcrystal entrainment, floc embedding, sludge floc adsorption / retention, and sludge-water separation processes. This results in sludge flocs with an inorganic salt content 2-3 times higher than that in the wastewater environment, which is then discharged with the remaining sludge. Simultaneously, organic pollutants and nitrogenous pollutants are degraded by the salt-tolerant activated sludge.

[0015] Table 1. Salt Mass Balance Table

[0016]

[0017] Furthermore, in this invention, the denitrification unit employs a two-stage denitrification / nitrification combined process. The denitrification / nitrification unit uses the MBBR process and is equipped with MBBR suspended packing material and a matching stainless steel screen.

[0018] Biological denitrification unit: After treatment by the first two units, the wastewater index is reduced to COD. crWith concentrations of ≤1000mg / L, ammonia nitrogen ≤400mg / L, total nitrogen ≤850mg / L, TDS ≤14000mg / L, and sulfate ≤8000mg / L, the nitrogen removal efficiency is within the applicable range for nitrification / denitrification bacteria. Under the conditions of a 4-day residence time in the nitrification tank, dissolved oxygen of 2-4mg / L, and MBBR filling ratio of 25%, and a 6-day residence time in the denitrification tank, dissolved oxygen of 0.2-0.5mg / L, the degradation of pollutants ammonia nitrogen and total nitrogen is achieved through a two-stage nitrification / denitrification combination, ultimately meeting emission standards.

[0019] In this invention, the process parameters of the inorganic salt retention and organic matter biodegradation synergistic unit are: dissolved oxygen at 2-4 mg / L, system sludge age controlled at 12-15 days, sludge concentration controlled at 8000 mg / L-12000 mg / L, and daily average sludge discharge controlled at 1 / 12-1 / 15 of the sludge volume.

[0020] Furthermore, in this invention, after the second vertical flow sedimentation tank has been commissioned and reached the design load, it is necessary to maintain MLSS at 8000mg / L-12000mg / L, MLVSS at 2400mg / L-4800mg / L, SV30 at 25%, SVI at 20.83-31.25, moisture content at 98.8%-99.2%, and residual sludge ash content at 60%-70%.

[0021] Furthermore, in this invention, the discharged residual sludge is high-ash sludge (ash content 60%-70%). According to SEM images magnified 5000-10000 times, the original activated sludge is mainly composed of organic matter continuous phase with clear microbial outlines. The organic components of the residual sludge in this invention are tightly wrapped by inorganic ash. The sample is composed of tightly packed fine inorganic ash particles with rich pore structure and a large number of flaky / granular / needle-shaped inorganic minerals exposed.

[0022] In this invention, the residual sludge, after being incinerated in a muffle furnace at 600°C, has the following specific sodium sulfate content:

[0023] Table 2 Composition of residual sludge after incineration

[0024]

[0025] Furthermore, in this invention, 16S rRNA high-throughput sequencing of activated sludge from the inorganic salt retention and organic biodegradation synergistic unit showed that the synergistic unit of inorganic salt retention and organic biodegradation significantly reshaped the microbial community structure. The pollutant degradation functional bacteria genera such as Actinobacteria and Proteobacteria under high-salt environments were highly enriched and showed a significant positive correlation with the treatment efficiency.

[0026] In this invention, the mass fraction of inorganic salts, mainly sodium sulfate, in the high-salt pyrimidine ring industrial wastewater is 2.5%-3%.

[0027] Furthermore, in this invention, the pollutants degraded by the activated sludge include COD. cr Ammonia nitrogen and total nitrogen.

[0028] In this invention, the process flow of the biochemical reaction system is further as follows: equalization tank → hydrolysis acidification tank → anaerobic tank → biological decarbonization tank → primary denitrification tank → primary nitrification tank → secondary denitrification tank → secondary nitrification tank → secondary sedimentation tank.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] 1. This invention completes the biochemical treatment of organic pollutants and the simultaneous separation of salt in high-salt pyrimidine ring wastewater within the same biochemical system, eliminating the need for separate membrane separation, evaporation crystallization, or other dedicated desalination units. The process is short and the equipment investment is low.

[0031] 2. This invention utilizes the interception, encapsulation, and enrichment of sodium sulfate solid particles, microcrystals, or salt-laden particles by salt-tolerant activated sludge flocs, allowing sodium sulfate to be discharged from the system along with the remaining sludge, thus realizing the transfer of salt from the aqueous phase to the sludge phase. This avoids problems such as viscous liquid and evaporator blockage caused by high-salt wastewater directly entering the evaporation system.

[0032] 3. This invention can simultaneously reduce COD in wastewater while removing sodium sulfate. cr It can synergistically treat wastewater with high salinity, high nitrogen, and high organic matter content by reducing ammonia nitrogen and total nitrogen.

[0033] 4. The residual sludge discharged by this invention has a high ash content, good sludge settling performance, and stable sludge-water separation effect, which is conducive to continuous system operation.

[0034] 5. This invention can effectively reduce the treatment cost of high-salt pyrimidine ring wastewater by about 80% compared with existing traditional technologies. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the biochemical treatment system of the present invention.

[0036] Figure 2 This is a scanning electron microscope (SEM) image of ordinary activated sludge in an embodiment of the present invention.

[0037] Figure 3 The image shown is a scanning electron microscope (SEM) image of the residual sludge discharged in an embodiment of the present invention, with an ash content of 70%.

[0038] Figure 4The image shows a scanning electron microscope (SEM) image of the remaining sludge during the commissioning process in this embodiment of the invention, with an ash content of 45%.

[0039] Figure 5 The image shows a scanning electron microscope (SEM) image of the remaining sludge during the commissioning process in this embodiment of the invention, with an ash content of 55%.

[0040] In the diagram: 1. Equalization tank; 2. Hydrolysis acidification tank; 3. Anaerobic tank; 4. First vertical flow sedimentation tank; 5. Biological decarbonization tank; 6. Second vertical flow sedimentation tank; 7. First-stage denitrification tank; 8. First-stage nitrification tank; 9. Second-stage denitrification tank; 10. Second-stage nitrification tank; 11. Secondary sedimentation tank; 12. Clear water tank. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0043] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0044] In the description of this invention, the terms "upper," "lower," "right," and "left," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used merely for distinction in description and have no special meaning.

[0045] Example

[0046] Please see Figures 1-5 This embodiment provides the following technical solution: a biochemical treatment and simultaneous salt separation method for high-salt pyrimidine ring industrial wastewater. The wastewater being treated is high-salt pyrimidine ring industrial wastewater generated during the production process of a pharmaceutical intermediate company. The COD of this wastewater... cr ≈10000mg / L, ammonia nitrogen≈500mg / L, total nitrogen≈1000mg / L, TDS≈30000mg / L, sulfate≈20000mg / L, pH is 6.5-8.5.

[0047] Specifically, the biological treatment system includes, in sequence along the water flow direction, an equalization tank 1, a hydrolysis acidification tank 2, an anaerobic tank 3, a first vertical flow sedimentation tank 4, a biological decarbonization tank 5, a second vertical flow sedimentation tank 6, a primary denitrification tank 7, a primary nitrification tank 8, a secondary denitrification tank 9, a secondary nitrification tank 10, and a secondary settling tank 11. Among these, hydrolysis acidification tank 2 and anaerobic tank 3 belong to the biological adsorption induction section; biological decarbonization tank 5 and the second vertical flow sedimentation tank 6 belong to the biological treatment and simultaneous salt separation section; and primary denitrification tank 7, primary nitrification tank 8, secondary denitrification tank 9, secondary nitrification tank 10, and secondary settling tank 11 belong to the biological nitrogen removal section. Each unit has corresponding process parameters and supporting reflux facilities, as detailed below:

[0048] 1. Equalization tank 1, for water homogenization, retention time 12h;

[0049] 2. Hydrolysis acidification tank 2, dissolved oxygen 0.2-0.5 mg / L, gas-to-water ratio 5:1, residence time 5 days, internal reflux ratio 200%;

[0050] 3. Anaerobic tank 3, dissolved oxygen ≦0.2mg / L, equipped with submersible agitator (25), residence time 5d, internal reflux ratio 200%;

[0051] 4. First vertical flow sedimentation: 4 hours, residence time: 4 hours, external reflux ratio: 50%;

[0052] 5. Biological decarbonation tank 5, dissolved oxygen at 2-4 mg / L, gas-to-water ratio at 50:1, MLSS controlled at 8000 mg / L~12000 mg / L, retention time 8 days;

[0053] 6. Second vertical flow sedimentation, retention time 4 hours, external reflux ratio 50%, sludge ash content controlled at 60-70%;

[0054] 7. Primary denitrification tank 7, dissolved oxygen 0.2-0.5 mg / L, retention time 3 days, internal reflux ratio 400%;

[0055] 8. Primary nitrification tank, dissolved oxygen at 2-4 mg / L, MBBR filling rate 25%, retention time 2.5 days;

[0056] 9. Secondary denitrification tank 9, dissolved oxygen 0.2-0.5 mg / L, retention time 1.5 days, internal reflux ratio 400%;

[0057] 10. Secondary nitrification tank 10, dissolved oxygen at 2-4 mg / L, MBBR filling rate 25%, retention time 1 day;

[0058] 11. Secondary sedimentation tank 11, retention time 8 hours, external reflux ratio 50%;

[0059] The specific processing steps are as follows:

[0060] 1. Wastewater conditioning:

[0061] High-salt pyrimidine ring industrial wastewater was introduced into equalization tank 1 to regulate the water volume and quality, and to control the pH at 7.0-8.5. Nutrients were added according to the carbon, nitrogen, and phosphorus ratio in the wastewater to meet the needs of microbial growth.

[0062] 2. Acclimation of salt-tolerant activated sludge:

[0063] The sludge acclimatization of other units was carried out according to the conventional model.

[0064] The salt-tolerant activated sludge acclimation in the biological decarbonization tank involved using aerobic activated sludge from a conventional industrial wastewater treatment system as inoculum. After inoculation, the sludge concentration (MLSS) was controlled at 4000–5000 mg / L. Acclimation was carried out by gradually increasing the influent salinity, with the salt mass fraction in the high-salt wastewater (primarily sodium sulfate with TDS) gradually increasing from 0.5% to 3.0%. Each stage was maintained for 7–10 days of stable operation. When the COD… cr After the removal rate, ammonia nitrogen removal rate and sludge settling performance remained stable, salt-tolerant activated sludge was obtained.

[0065] 3. Biochemical reactions:

[0066] The adjusted wastewater is continuously fed into the biochemical reaction unit, passing sequentially through the biological adsorption induction section, the biochemical treatment and simultaneous salt separation section, and the biochemical denitrification section.

[0067] Biosorption induction unit: Maintains a low dissolved oxygen concentration to achieve high EPS induction while simultaneously achieving high COD concentration.cr Significant degradation and further improvement in biochemical B / C ratio.

[0068] Biochemical treatment and simultaneous salt separation unit: This unit raises the system pH to 7.8-8.5 through high-intensity aeration, triggering in-situ chemical precipitation reactions between metal cations adsorbed by extracellular polymers and anions such as sulfate in the wastewater within and on the surface of activated sludge flocs. This reduces the effective salinity of the floc microenvironment. In a specific high-salt pyrimidine ring wastewater biochemical system, sodium sulfate is enriched from the aqueous phase to the sludge phase through microcrystal entrainment, floc embedding, sludge floc adsorption / retention, and sludge-water separation processes. Simultaneously, organic pollutants and nitrogenous pollutants are degraded by salt-tolerant activated sludge.

[0069] Biological denitrification unit: After treatment by the first two units, the wastewater index is reduced to COD. cr The pollutants ammonia nitrogen and total nitrogen are degraded through a two-stage nitrification / denitrification combination, with ammonia nitrogen and total nitrogen levels ≤1000mg / L, ammonia nitrogen ≤400mg / L, total nitrogen ≤850mg / L, TDS ≤14000mg / L, and sulfate ≤8000mg / L, ultimately meeting emission standards.

[0070] Table 3. Statistics on final removal results

[0071]

[0072] 4. Simultaneous salt separation:

[0073] During the biochemical reaction process, sodium sulfate in the wastewater enters the sludge phase in the form of microcrystals, solid particles, flocs carrying salt, or sludge flocs encapsulating and enriching. After sludge-water separation in the second vertical flow sedimentation tank 6, the salt-enriched sludge settles to the bottom of the sedimentation tank. A portion of this sludge is recycled to maintain the system's sludge concentration, while the other portion is discharged from the system as excess sludge, thus separating sodium sulfate from the aqueous phase along with the excess sludge. The sludge age is controlled at 12-15 days, the sludge concentration is controlled at 8000 mg / L to 12000 mg / L, and the daily average sludge discharge is controlled at 1 / 12 to 1 / 15 of the sludge volume. The ash content of the discharged excess sludge reaches 60-70%.

[0074] In this embodiment, without pretreatment desalination methods such as evaporation and membrane separation, direct biochemical reaction of high-salt pyrimidine ring industrial wastewater was achieved, with an influent COD concentration of [missing information]. cr With COD levels of approximately 10000 mg / L, ammonia nitrogen approximately 500 mg / L, total nitrogen approximately 1000 mg / L, TDS approximately 30000 mg / L, sulfate approximately 20000 mg / L, and pH between 6.5 and 8.5, effluent COD was achieved through biochemical treatment and simultaneous salt separation. cr≤500mg / L, ammonia nitrogen ≤20mg / L, total nitrogen ≤50mg / L, TDS ≤14000mg / L, sulfate ≤8000mg / L.

[0075] Within 90 days after the system has been running stably, the effluent COD cr Ammonia nitrogen and total nitrogen levels consistently meet emission standards. The ash content of the residual sludge reaches 60%–75%, and the sludge exhibits good settling performance with no significant sludge bulking. Compositional analysis of the residual sludge ash reveals enrichment of sodium and sulfur elements, indicating that most of the sodium sulfate in the wastewater has transferred from the aqueous phase to the sludge phase and is discharged from the system with the residual sludge.

[0076] Comparative Example 1

[0077] A common pretreatment solution for this type of wastewater is "membrane concentration + MVR evaporation," followed by traditional biological treatment of the effluent. This solution can achieve COD control for this wastewater. cr Ammonia nitrogen and total nitrogen levels consistently meet discharge standards, with wastewater treatment costs approximately 120 yuan / m³. 3 The pretreatment cost is approximately 90 yuan / m³. 3 Waste salt treatment cost is approximately 10 / m³ 3 Biochemical treatment cost 20 yuan / m³ 3 Furthermore, MVR evaporation facilities often become clogged because the centrifuged mother liquor needs to be reused for evaporation multiple times. Each cleaning takes at least 2-3 days, which seriously affects production.

[0078] By adopting this method, COD of pollutants can be obtained without pretreatment. cr Ammonia nitrogen and total nitrogen levels will consistently meet discharge standards, while approximately 60% of TDS can be removed through biochemical treatment and simultaneous salinity separation. Using this solution, the cost of treating wastewater of the same quality is approximately 25 yuan / m³. 3 The pretreatment cost is 0 yuan / m³ 3 Waste salt treatment cost is approximately 5 / m³ 3 Biochemical treatment cost 20 yuan / m³ 3 This saves approximately 80% in costs compared to before.

[0079] Comparative Example 2

[0080] Ordinary activated sludge without salt tolerance acclimation was used to directly treat high-salt pyrimidine ring industrial wastewater with a sodium sulfate mass fraction of approximately 3.0%, with other operating conditions the same as in the previous example. In the initial stage of operation, the ordinary activated sludge exhibited decreased activity, loose flocs, and poorer settling performance, resulting in decreased COD. crThe ammonia nitrogen removal rate fluctuated significantly, making long-term stable operation of the system difficult. After 7 days of continuous operation, the entire biological system collapsed, the aerobic sludge developed a distinct fishy odor, and the removal rate approached zero. Compared with the example, ordinary activated sludge that has not undergone salt tolerance acclimation has poor adaptability to high-salt pyrimidine ring wastewater, making it difficult to achieve a stable coupling of organic pollutant and nitrogen pollutant removal with simultaneous salt separation.

[0081] In summary, this invention achieves effective treatment of high-salt pyrimidine ring industrial wastewater without the need for pretreatment by constructing a combination of a bio-adsorption induction section, a biochemical treatment and simultaneous salt separation section, and a biochemical denitrification section. At the same time, under the conditions of the embodiments of this invention, the operating cost is reduced by about 80% compared with the comparative process.

[0082] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for biochemical treatment and simultaneous salt separation of high-salt pyrimidine ring industrial wastewater, characterized in that, Includes the following steps: S1. Introduce high-salt pyrimidine ring industrial wastewater into a biochemical reaction system. The biochemical reaction system includes at least a bio-adsorption induction unit, an inorganic salt interception and organic matter biodegradation synergistic unit, and a denitrification unit. S2. In the synergistic unit of inorganic salt interception and organic matter biodegradation, sodium sulfate crystals / particles in the wastewater are physically intercepted by activated sludge flocs and enriched inside the sludge flocs, while the activated sludge biodegrades the organic matter in the wastewater. S3. Sodium sulfate that is trapped and enriched inside the sludge flocs is discharged from the system along with the remaining sludge, realizing the simultaneous separation of sodium sulfate from wastewater.

2. The method for biochemical treatment and simultaneous salt separation of high-salt pyrimidine ring industrial wastewater according to claim 1, characterized in that: The hydrolysis acidification section and anaerobic section of the biochemical reaction system are set as bio-adsorption induction units. The bio-adsorption induction units operate under low dissolved oxygen conditions, with a dissolved oxygen concentration of 0.2-0.5 mg / L, inducing activated sludge to secrete extracellular polymers. Through the electrostatic adsorption and complexation of extracellular polymers, metal cations in wastewater are enriched, forming activated sludge mixed liquor loaded with metal cations.

3. The method for biochemical treatment and simultaneous salt separation of high-salt pyrimidine ring industrial wastewater according to claim 1, characterized in that: The denitrification unit employs a two-stage denitrification / nitrification combined process.

4. The method for biochemical treatment and simultaneous salt separation of high-salt pyrimidine ring industrial wastewater according to claim 3, characterized in that: The denitrification / nitrification unit adopts the MBBR process and is equipped with MBBR suspended packing and a matching stainless steel screen.

5. The method for biochemical treatment and simultaneous salt separation of high-salt pyrimidine ring industrial wastewater according to claim 1, characterized in that: The concentration of activated sludge in the inorganic salt retention and organic biodegradation synergistic unit is 8000 mg / L-12000 mg / L.

6. The method for biochemical treatment and simultaneous salt separation of high-salt pyrimidine ring industrial wastewater according to claim 1, characterized in that: The discharge amount of the remaining sludge is controlled according to the ash content in the biochemical reaction system, and the sludge age of the system is controlled to be 12-15 days.

7. The method for biochemical treatment and simultaneous salt separation of high-salt pyrimidine ring industrial wastewater according to claim 1, characterized in that: The ash content of the discharged sludge is 60%-70%.

8. The method for biochemical treatment and simultaneous salt separation of high-salt pyrimidine ring industrial wastewater according to claim 1, characterized in that: The mass fraction of inorganic salts, mainly sodium sulfate, in the high-salt pyrimidine ring industrial wastewater is 2.5%-3%.

9. The method for biochemical treatment and simultaneous salt separation of high-salt pyrimidine ring industrial wastewater according to claim 1, characterized in that: The pollutants degraded by the activated sludge include COD. cr Ammonia nitrogen and total nitrogen.

10. The method for biochemical treatment and simultaneous salt separation of high-salt pyrimidine ring industrial wastewater according to claim 1, characterized in that: The process flow of the biochemical reaction system is as follows: equalization tank → hydrolysis acidification tank → anaerobic tank → biological decarbonization tank → primary denitrification tank → primary nitrification tank → secondary denitrification tank → secondary nitrification tank → secondary sedimentation tank.

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