Method and device for domesticating salt-tolerant activated sludge

Abstract

The invention discloses a domestication method and device for salt-tolerant activated sludge, and belongs to the technical field of microculture and sewage treatment devices. In order to solve the technical problems that in the prior art, domestication of salt-tolerant activated sludge is achieved in the mode that salinity is increased in a gradient mode, obtained sludge is poor in genetic adaptability and long in domestication period, the domestication method of the salt-tolerant activated sludge comprises the steps that fresh sludge with the sludge concentration MLSS being 5000-6000 mg / L and the MLSS / MLVSS being larger than or equal to 0.8 is put into a domestication device; the domestication device comprises an anaerobic-anoxic reaction zone and an aerobic reaction zone which are communicated with each other; the concentration of salt in the system is controlled to be 3-5%, when the CODcr removal rate is smaller than or equal to 30%, the CODcr concentration gradient is gradually increased at the gradient of 500-1000 mg / L in the modes of increasing nutrition addition, increasing the aeration rate of the aerobic reaction zone, returning the sludge in the aerobic reaction zone to the anaerobic-anoxic reaction zone, supplementing fresh sludge, discharging inactivated sludge and the like, and the obtained salt-tolerant activated sludge is good in heredity and high in salt tolerance. And the domestication period is short.

Description

Technical Field

[0001] The invention belongs to the technical field of microbial culture and sewage treatment equipment, and more specifically, relates to a method and device for taming salt-tolerant activated sludge. Background Art

[0002] As a widely used wastewater biological treatment technology, the activated sludge process mainly relies on the microbial community in the activated sludge to degrade organic matter in the sewage. However, in a high-salinity environment, the traditional activated sludge process faces severe challenges. The high concentration of inorganic salts in high-salinity wastewater will inhibit the activity of microorganisms, affect their growth and metabolism, and thus reduce the efficiency of sewage treatment. It is feasible to treat saline sewage through domestication. During the domestication process, microorganisms balance the osmotic pressure in the cell through osmotic pressure regulation mechanisms to protect the protoplasm in the cell. These regulatory mechanisms include aggregating low molecular weight substances to form a new extracellular protective layer, regulating metabolic pathways, and changing genetic composition.

[0003] At present, the methods for salt tolerance of activated sludge can be mainly divided into the bacterial method and the natural domestication method. The bacterial method changes the population structure of activated sludge by adding salt-tolerant bacteria to the seed sludge, thereby improving the tolerance to high salinity, but the operating cost is high and the feasibility is reduced. The natural domestication method is to domesticate by gradually increasing the salinity of the wastewater, but the population diversity is relatively low, and the suitable salinity that can be tolerated after successful domestication still needs to be controlled within 5%. The prior art discloses that the salinity of wastewater is gradually increased at a set rate to acclimate the sludge. For example, the Chinese invention application publication number is CN106396321A, the application date is June 17, 2016, and the invention name is "A method for acclimatizing activated sludge of high-salinity organic wastewater with improved salt tolerance by pressurization". In the disclosed scheme, the salinity of the wastewater in the initial seed sludge is gradually increased at a set rate, and each rate is acclimatized for a set number of days. The acclimatization process adopts the SBR operation mode. The acclimatization process is carried out in a closed constant pressure reactor, the absolute pressure is controlled at 0.2-0.4 MPa, and the aeration volume makes the dissolved oxygen in the reactor within 10 mg / L, which can effectively improve the removal effect of organic matter in high-salinity wastewater of 3%-5%. This scheme has the following shortcomings: (1) The acclimatization period is long, and the microorganisms need to gradually adapt to the gradually increasing salt concentration during this process. (2) The microorganisms in the acclimatized activated sludge have a limited tolerance range for salt and are sensitive to environmental changes. When the chloride ion environment suddenly changes, the adaptability of the microorganisms will immediately disappear. (3) The adaptability of microorganisms during the acclimation process is a temporary physiological adjustment and does not have genetic characteristics. This means that once the environment changes, the adaptability of microorganisms may be quickly lost. (4) Compared with the method of directly using salt-tolerant bacteria or diluting the influent, the acclimation method of gradually increasing the salt concentration is more complicated to operate and requires precise control of the rate of increase in salt concentration and acclimation conditions. (5) Although the method of gradually increasing the salt concentration can theoretically improve the salt tolerance range and treatment efficiency of the system, in practice it may increase economic costs due to the need for longer acclimation time and complex operations.

[0004] However, it is difficult to directly acclimate sludge in a high-salt environment so that it has the ability to degrade organic matter. The main reasons are as follows: (1) High-salt environment has an inhibitory and toxic effect on microbial growth and metabolism. Microorganisms need to balance the osmotic pressure in the cell through osmotic pressure regulation mechanisms in a high-salt environment. These regulatory mechanisms include aggregating low-molecular-weight substances to form a new extracellular protective layer, regulating metabolic pathways, and changing genetic composition. These physiological adjustments are temporary, not hereditary, and sensitive to environmental changes. Once the environment changes, the adaptability of the microorganism will disappear immediately. (2) The concentration of activated sludge decreases in the early stage of acclimatization because the increase in salt solution is toxic to microorganisms, causing some microorganisms to die, showing negative growth. During the acclimatization process, microorganisms need to gradually adapt to the high-salt environment. This process may be slow and require high operating conditions. (3) Salinity enhances the respiration of microorganisms and the lysis of cells, reducing the biodegradability and degradability of organic matter, and reducing the removal rate and degradation rate of organic matter. (4) In the process of cultivating and acclimatizing salt-tolerant activated sludge, the source of inoculated sludge needs to be considered. There are differences in the salt tolerance acclimation process of activated sludge from different sources, and the salinity increase rate also affects the final treatment effect.

[0005] Therefore, developing a new salt-tolerant activated sludge acclimatization method to improve its treatment effect in a higher salinity range is of great significance for the treatment of actual high-salinity wastewater. Summary of the invention

[0006] 1. Problem to be solved

[0007] In view of the technical problems that in the prior art, the domestication of salt-tolerant activated sludge is carried out by increasing the salinity in a gradient manner, resulting in poor genetic adaptability of the sludge and a long domestication period, the present invention provides a method for domesticating salt-tolerant activated sludge. On the other hand, the present invention also provides a device for domesticating salt-tolerant activated sludge.

[0008] 2. Technical solution

[0009] The technical solution adopted by the present invention is as follows:

[0010] Based on the purpose of the present invention, the first aspect of the present invention provides a method for acclimating salt-tolerant activated sludge, comprising the steps of:

[0011] S1. Add fresh sludge into the acclimation device, wherein the moisture content of the fresh sludge is 98% to 99%, VSS / TSS ≥ 0.8 ± 0.1, and SVI is 85 to 150; the acclimation device comprises an anaerobic-anoxic reaction zone and an aerobic reaction zone which are interconnected, and at the beginning of acclimation, the sludge concentration MLSS is controlled at 5000 to 6000 mg / L;

[0012] S2, control the salt concentration in the system to 3-5%, when CODcr removal rate ≤30%, through

[0013] Adding more nutrients to the acclimation device so that the proportion of the added carbon source reaches 1 / 4 to 1 / 5; and / or,

[0014] Increase the aeration volume in the aerobic reaction zone to make the dissolved oxygen in the aerobic reaction zone reach 5-6 mg / L; and / or,

[0015] Returning the sludge from the aerobic reaction zone to the anaerobic-anoxic reaction zone, with the return ratio controlled at 100% to 200%; and / or,

[0016] Add fresh sludge, with the new sludge dosage accounting for 1 / 5 to 1 / 3; and / or,

[0017] Discharge of inactivated sludge, the amount of inactivated sludge discharged accounts for 1 / 5 to 1 / 4, until the CODcr removal rate is ≥ 75%;

[0018] S3. Increase CODcr concentration gradient gradually with a gradient of 500-1000 mg / L. The acclimatization period of each CODcr concentration gradient is 5-10 days. Control the sludge age for 20-25 days. When the sludge concentration is ≥10000-12000 mg / L, discharge the sludge and control the sludge concentration to remain stable.

[0019] When the influent CODcr is ≥10000 mg / L and the removal rate is ≥70%, the acclimation is terminated to obtain the salt-tolerant activated sludge.

[0020] According to the salt-tolerant activated sludge acclimation method of any embodiment of the first aspect of the present invention, the method used to control the salt concentration in the system is to add salts; the salts are sodium chloride and sodium sulfate, and 3≤CODcr / SO 4 2- ≤10.

[0021] The method used for controlling the salt concentration in the system as described herein can also be used to directly add wastewater containing high salinity to the system to adjust the salt concentration in the system to 3-5%.

[0022] In sewage treatment, CODcr (chemical oxygen demand) and SO 4 2- (sulfate ion) ratio is an important parameter. 4 2- When the ratio is between 3 and 10: promote microbial metabolic balance; improve organic matter removal efficiency; enhance the system's ability to resist shock; optimize electron flow distribution; improve salt tolerance: in the domestication process of salt-tolerant activated sludge, gradually increasing the salinity method is more conducive to the cultivation of salt-tolerant bacteria. Appropriate CODcr / SO 42- The ratio helps to improve the tolerance of sludge microorganisms to salt concentration, thereby enhancing the salt tolerance of sludge; Stable operation: Maintaining an appropriate CODcr / SO 4 2- The ratio helps to maintain the stable operation of the activated sludge system, especially in a high salinity environment; reduce sludge production: the appropriate CODcr / SO 4 2- ratio helps to reduce the production of excess sludge due to reduced activity of sulfate-reducing bacteria, thereby reducing the cost of sludge handling and disposal.

[0023] According to the salt-tolerant activated sludge acclimation method of any embodiment of the first aspect of the present invention, the increased nutrient addition includes: the carbon source is wastewater carbon source and glucose in a mass ratio of 4:1; CODcr:N:P is 100-300:5:1.

[0024] Maintaining an appropriate CODcr:N:P ratio is essential for the growth of microorganisms, ensuring that the growth of microorganisms is not restricted by lack of carbon, nitrogen or phosphorus sources. In the denitrification process, the appropriate carbon-nitrogen ratio (C / N) is 5:1, while the proliferation ratio of foreign microorganisms in aerobic tanks is 100-300:5:1. By maintaining this ratio, the denitrification efficiency can be improved, especially when total nitrogen is removed in anoxic tanks. The addition of industrial glucose can improve the sedimentation and dewatering properties of sludge. In the sewage treatment process, the addition of industrial glucose can promote the biodegradation process of certain difficult-to-degrade pollutants. By compounding different reaction rates and different types of carbon sources, the carbon source and process residence time can be better matched, the diversity and activity of microorganisms can be improved, and the denitrification efficiency can be improved.

[0025] According to the method for acclimating salt-tolerant activated sludge of any embodiment of the first aspect of the present invention, the wastewater carbon source is a biomedical wastewater carbon source and does not contain degradable organic matter; the fresh sludge is taken from a biochemical sludge concentration tank of a food processing plant sewage treatment station.

[0026] Carbon sources such as pharmaceutical wastewater generally do not contain difficult-to-degrade organic matter, which helps to screen and domesticate microorganisms with stronger salt tolerance. Fresh sludge in food industry wastewater contains microbial communities that adapt to the characteristics of food wastewater. These microorganisms may help improve the stability and impact resistance of the system during the salt tolerance domestication process. In addition, fresh sludge in food industry wastewater may contain highly active microorganisms that can effectively degrade organic matter and improve the removal efficiency of organic matter.

[0027] According to the salt-tolerant activated sludge acclimation method of any embodiment of the first aspect of the present invention, the redox potential of the anoxic reaction zone is controlled at -100mV to +100mV; the redox potential of the aerobic reaction zone is controlled at +200mV to +400mV.

[0028] Under anoxic conditions, ORP control between -100mV and +100mV helps promote biological reactions under anoxic conditions, such as denitrification. This ORP range indicates that the system is in the active area of ​​​​facultative anaerobic microorganisms, which perform aerobic respiration above +100mV and anaerobic respiration below +100mV.

[0029] Controlling the redox potential (ORP) in the aerobic reaction zone within the range of +200mV to +400mV can promote the oxidation and decomposition of organic matter. Under aerobic conditions, a higher ORP value indicates that the system has a stronger oxidation capacity, which is conducive to the degradation of organic matter by aerobic microorganisms and improves the removal efficiency of COD. Optimize the nitrification process: Aerobic microorganisms can grow above +100mV, and the optimum is +300 to +400mV. Within this ORP range, the growth of nitrifying bacteria and the nitrification reaction can be promoted, thereby improving the conversion rate of ammonia nitrogen. Controlling the aerobic aeration volume through ORP can avoid insufficient or excessive aeration time, ensure the water quality of the treated water, and save energy at the same time.

[0030] According to the method for acclimating salt-tolerant activated sludge of any embodiment of the first aspect of the present invention, the anaerobic-anoxic reaction zone is aerated once every 4 to 6 hours.

[0031] Aeration can provide oxygen for microorganisms, promote nitrification reaction, and convert ammonia nitrogen into nitrite and nitrate, which is a key step in the biological denitrification process. Appropriate aeration frequency helps to control the expansion problem of activated sludge, because excessive aeration may cause sludge flocs to rupture, while insufficient aeration may cause sludge expansion. Aeration can accelerate the degradation and oxidation of organic matter, significantly improving sewage treatment efficiency and effluent quality. Appropriate aeration frequency helps to enhance the formation of sludge flocs, improve the sedimentation performance of sludge, and reduce suspended solids in effluent. Excessive aeration is not conducive to the normal growth and reproduction of activated sludge, and may cause sludge flocs to rupture. This situation can be avoided and the sludge can be kept in a healthy state by aerating every 4 to 6 hours.

[0032] In the method for acclimating salt-tolerant activated sludge according to any embodiment of the first aspect of the present invention, a flocculant is added to the aerobic reaction zone.

[0033] As described herein, the flocculant is preferably activated carbon powder, with a dosage of 0.01 kg-carbon / m 3 -Wastewater.

[0034] The addition of flocculants can improve the settling performance of sludge, reduce the problem of sludge expansion, and thus increase the settling speed and settling efficiency of sludge. Adding flocculants can promote the formation of aerobic granular sludge, improve the settling performance of granular sludge, stabilize the sludge mass concentration, and provide good effluent quality. Adding an appropriate amount of flocculants can reduce sludge production because flocculants can promote the aggregation and settling of sludge and reduce suspended solids in the system.

[0035] The second aspect of the present invention provides a salt-tolerant activated sludge acclimation device for implementing the salt-tolerant activated sludge acclimation method, the acclimation device comprising: an anaerobic-anoxic reactor and an aerobic reactor;

[0036] The upper parts of the anaerobic-anoxic reactor and the aerobic reactor are connected via a pipeline;

[0037] The lower parts of the anaerobic-anoxic reactor and the aerobic reactor are connected via a sludge return pipe, and the sludge return pipe is also connected to a sludge return pump;

[0038] The bottoms of the anaerobic-anoxic reactor and the aerobic reactor are both provided with microporous aerators;

[0039] The anaerobic-anoxic reactor is provided with a fluidized bed filler;

[0040] The aerobic reactor is provided with a stirrer;

[0041] The aerobic reactor is provided with a mud discharge port.

[0042] According to the salt-tolerant activated sludge acclimatization device of any embodiment of the second aspect of the present invention, the fluidized bed filler occupies ≥ 60% of the volume of the anaerobic-anoxic reactor.

[0043] According to the salt-tolerant activated sludge acclimation device of any embodiment of the second aspect of the present invention, the height-to-diameter ratios of the anaerobic-anoxic reactor and the aerobic reactor are both 2.5-5.

[0044] As described herein, the specifications of the anaerobic-anoxic reactor and the aerobic reactor are preferably 1.5 m high, 0.6 m in diameter, and 0.3 m in total effective volume. 3 The material is high-strength acrylic sheet. A row of sampling valves are set on the wall of the anaerobic-anoxic reactor and the aerobic reactor, and both are equipped with a pH meter, dissolved oxygen meter, and thermometer. A sludge outlet is set at the bottom of the aerobic reactor for collecting domesticated sludge.

[0045] 3. Beneficial effects

[0046] (1) The domestication method of salt-tolerant activated sludge of the present invention: a. High-efficiency salt-tolerant domestication: By gradually domesticating the activated sludge in a high-salinity (3% to 5%) environment, the present invention successfully screened out strains with high tolerance to high salt. These strains can remain active in extreme environments, significantly improving the salt tolerance of the sewage treatment system. b. Optimized sludge management: By controlling the selection of fresh and suitable sludge, sludge concentration MLSS (5000 to 6000 mg / L), and the initial CODcr concentration of domestication, the activity and treatment efficiency of the initial sludge are ensured. At the same time, by controlling the sludge concentration (discharging sludge when ≥10000 to 12000 mg / L) to maintain stability, the sludge management is optimized. c. Gradually improve the CODcr treatment efficiency: By gradually increasing the CODcr concentration gradient with a gradient of 500-1000 mg / L, and controlling each acclimatization cycle to 5-10 days, this scheme gradually enhances the adaptability of activated sludge to high CODcr loads, and finally achieves the goal of removal rate ≥70% when the influent CODcr ≥10000 mg / L. d. Flexible nutrition and aeration control: When the CODcr removal rate is ≤30%, the treatment conditions are flexibly adjusted by increasing nutrient addition, increasing aeration volume, sludge return, supplementing fresh sludge or increasing sludge discharge to increase the CODcr removal rate to ≥75%, thereby enhancing the adaptability and stability of the system. e. Environmentally friendly and cost-effective: The treatment efficiency of high-salt wastewater is improved through biological treatment, the demand for chemical treatment is reduced, the treatment cost is reduced, and the risk of secondary pollution to the environment is reduced. f. Broad application prospects: The method of the present invention is not only suitable for industrial wastewater treatment, but can also be extended to other sewage treatment fields that require high salt tolerance, and has broad application prospects. g. Easy and efficient operation: By gradually increasing the salinity and CODcr gradient, the domestication process is simplified, easy to operate and manage, and suitable for sewage treatment facilities of various sizes. It enriches the types of activated sludge and increases the adaptability of sludge to salinity. Through direct screening, domestication, and cultivation in a high-salt environment, the domestication cycle is shortened and the elimination of activated sludge with low tolerance to high salt is accelerated.

[0047] (2) The salt-tolerant activated sludge acclimation device of the present invention: a. Flexible and stable regulation: The split design allows the anaerobic-anoxic reactor and the aerobic reactor to be regulated separately, so that the system can recover quickly after being disturbed. This design improves the flexibility and stability of the system, so that each reactor can be optimized according to specific treatment needs. b. Reduce inhibition: The short-range nitrification stage in the split process can reduce certain poisons and organic matter and prevent them from directly entering another reactor, thereby reducing the inhibitory effect on the activated sludge. This is particularly important for treating wastewater containing poisons and organic matter, and improves the system's ability to withstand shock loads. c. Improve volume utilization and efficiency: The aerobic tank (aerobic module) is in a constant aeration state, which increases the volume utilization of the tank and improves the utilization of the equipment; the blower pressure is stable and efficient; the air oxygen conversion utilization rate is high, and the volume load and sludge load are high. e. Enhanced biofilm reaction: The anaerobic-anoxic reactor is equipped with a fluidized bed filler, the aerobic reactor is doped with activated carbon powder, and is equipped with a mixer. These designs help to form a stable biofilm, enhance the contact between microorganisms and pollutants in sewage, and improve mass transfer efficiency.

[0048] Instruction Manual

[0049] Figure 1 This is a schematic diagram of the structure of the salt-tolerant activated sludge acclimatization device in the embodiment of the present application;

[0050] In the figure:

[0051] 1. Anaerobic-anoxic reactor; 2. Aerobic reactor; 3. Fluidized bed filler; 4. Microporous aerator; 5. Sampling port; 6. Sludge outlet; 7. Mixer; 8. Rotor flowmeter; 9. Aeration fan; 10. Pipeline; 11. Thermometer; 12. Dissolved oxygen meter; 13. ORP meter; 14. Sludge return pipeline; 15. Sludge return pump. DETAILED DESCRIPTION

[0052] All documents cited in the present invention are incorporated herein by reference in their entirety, and if the meanings expressed in these documents are inconsistent with the present invention, the description of the present invention shall prevail. In addition, the various terms and phrases used in the present invention have the general meanings known to those skilled in the art. Even so, the present invention still hopes to provide a more detailed description and explanation of these terms and phrases. If the terms and phrases mentioned are inconsistent with the known meanings, the meanings expressed in the present invention shall prevail.

[0053] When items are described by using the conjunction terms "... and / or...," etc., the description should be understood to include any one of the associated listed items and all combinations of one or more thereof.

[0054] In general, the use of the term "about" indicates an approximate value that may vary depending on the desired properties obtained by the disclosed subject matter, and will be interpreted in a context-dependent manner based on function. Therefore, one of ordinary skill in the art will be able to interpret a certain degree of difference on a case-by-case basis. In some cases, the number of significant figures used when expressing a particular value can be a representative technique for determining the difference allowed by the term "about". In other cases, a gradient in a range of values ​​can be used to determine the range of differences allowed by the term "about". Further, all ranges in this disclosure are inclusive and combinable, and reference to the values ​​stated in the range includes each value within the range.

[0055] In the present invention, the term "comprising" or "containing" means that various components can be used together in the composition of the present invention. Therefore, the terms "consisting mainly of" and "consisting of" are included in the terms "comprising" or "containing".

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs; the terms used herein and / or include any and all combinations of one or more of the associated listed items.

[0057] The following will disclose any feature in this specification, unless otherwise stated, can be replaced by other equivalent or alternative features with similar purposes. Unless otherwise stated, each feature is just an example in a series of equivalent or similar features. It is described only to help understand the present invention and should not be regarded as a specific limitation of the present invention. Those who do not indicate specific conditions in the embodiment are carried out according to normal conditions or the conditions recommended by the manufacturer. Those who do not indicate the manufacturer of the reagents or instruments used are all conventional products that can be purchased.

[0058] The present invention is further described below in conjunction with specific embodiments.

[0059] Example 1

[0060] The schematic diagram of the device structure used in the salt-tolerant activated sludge acclimation method provided in this embodiment is as follows: Figure 1 As shown,

[0061] The acclimation device includes an anaerobic-anoxic reactor 1 and an aerobic reactor 2 of split design, the upper parts of the anaerobic-anoxic reactor 1 and the aerobic reactor 2 are connected by a pipe 10, and the lower parts are connected by a sludge return pipe 14. Through the pipe 10 and the sludge return pipe 14, sludge circulation and return between the two reactors can be achieved, which helps to maintain the biomass and treatment efficiency of the system, especially in the face of water quality fluctuations. The side walls of the anaerobic-anoxic reactor 1 and the aerobic reactor 2 are both provided with multiple sampling ports 5 for real-time sampling.

[0062] The bottom of the anaerobic-anoxic reactor 1 and the aerobic reactor 2 are both provided with a microporous aerator 4. The main function of the microporous aerator 4 is to introduce air into the reactor to provide sufficient dissolved oxygen for aerobic microorganisms to use and promote the oxidative decomposition of organic matter. It introduces gas into the water body through micropores or small pore structures to form bubbles, thereby increasing the oxygen content in the water. In addition, the microporous aerator also helps to stir the suspended matter in the pool to prevent it from sinking and strengthen the contact between the organic matter in the pool and the microorganisms and dissolved oxygen. The microporous aerator 4 is connected to the aeration fan 9 through a rotor flowmeter 8.

[0063] The anaerobic-anoxic reactor 1 and the aerobic reactor 2 are also provided with a thermometer 11, a dissolved oxygen meter 12, and an ORP meter 13, respectively. The thermometer 11 is used to measure the temperature in the reactor. The dissolved oxygen meter 12 is used to monitor the dissolved oxygen (DO) level in the reactor. The ORP meter 13 (oxidation-reduction potential meter) is used to measure the oxidation-reduction potential in the reactor, which is a comprehensive indicator that characterizes the relative degree of oxidizability or reducibility of the medium. Monitoring of the ORP value helps to understand the dynamic balance of oxidation and reduction reactions in the reactor, and has guiding significance for controlling biochemical reactions such as nitrification and denitrification in the anaerobic-anoxic reactor.

[0064] The anaerobic-anoxic reactor 1 is also provided with a fluidized bed filler 3. In this embodiment, the volume of the sulfidized fluidized bed filler 3 is 60% of the volume of the anaerobic-anoxic reactor 1. The aerobic reactor 2 is also provided with a stirrer 7 for stirring and aerating.

[0065] The specifications of the anaerobic-anoxic reactor 1 and the aerobic reactor 2 in this embodiment are both 1.5 m high, 0.6 m in diameter, and 0.3 m in total effective volume. 3 , the material is high-strength acrylic sheet. In actual use scenarios, when the height-to-diameter ratio of the anaerobic-anoxic reactor 1 and the aerobic reactor 2 is 2.5-5, the invention purpose of the present application can be achieved.

[0066] The specific domestication method is as follows:

[0067] Fresh sludge is added into the above-mentioned acclimation device. The fresh sludge is taken from the biochemical sludge concentration tank of the sewage treatment station of the food processing plant. The sludge moisture content is 98% to 99%; VSS / TSS ≥ 0.8 ± 0.1; SVI is 85 to 150. At this time, the initial salt concentration of the system is 0.5%, MLSS is 6000 mg / L, and CODcr is 3500 mg / L. After about 7 days of acclimation, when the influent CODcr is 4500 mg / L (carbon source composed of glucose), the CODcr removal rate is about 95%, and the sludge sedimentation performance is good.

[0068] At this time, the inlet salinity is controlled to be 3.5%, CODcr 3500mg / L, ammonia nitrogen 100mg / L, and total phosphorus 25mg / L. The salt content is prepared by adding sodium chloride and sodium sulfate, and the CODcr / SO is controlled to be 3≤ 4 2- ≤10, wherein CODcr is prepared by carbon source of biomedical wastewater (without refractory organic matter): external glucose carbon source in a ratio of 4:1. Parameters of biochemical biomedical wastewater: CODcr is 6000-8000 mg / L, total nitrogen is 70-100 mg / L, total phosphorus is 10-15 mg / L, and salt is 2%. In this embodiment, ammonia nitrogen is regulated by adding urea, and total phosphorus is regulated by adding potassium dihydrogen phosphate.

[0069] When the acclimation starts and a salinity of 3.5% is introduced into the acclimation device, the CODcr removal rate drops to 30% by: increasing the external carbon source, nitrogen source and phosphorus source in the aerobic reactor to make the CODcr:N:P ratio in the system reach 100:5:1-150:5:1; increasing the aeration volume in the aerobic reactor to make the dissolved oxygen reach 5-6 mg / L; increasing the external carbon source, nitrogen source and phosphorus source in the anaerobic reactor to make the CODcr:N:P ratio in the system reach 200:5:1-300:5:1; increasing the sludge return from the aerobic reactor to the anaerobic-anoxic reactor, and controlling the return ratio at 100%-200%; adding fresh sludge from the outside depending on the MLVSS / MLSS ratio. At the same time, the inactivated sludge is replaced, the proportion of new sludge added reaches 1 / 5~1 / 3, and the proportion of discharged inactivated sludge reaches 1 / 5~1 / 4, so that MLVSS / MLSS≥0.8. After about 10~15 days of adaptation, the CODcr removal rate rises to 75%.

[0070] The concentration of CODcr is gradually increased, and each gradient increase requires an adaptation period of about 5 to 7 days. In this embodiment, each gradient is a CODcr concentration of 1000 mg / L. CODcr is formed by a 5:1 ratio of biomedical wastewater carbon source to an external glucose carbon source. The higher the influent CODcr concentration, the longer the required acclimatization adaptation period. The redox potential of the anoxic reaction zone is controlled at -100mV to +100mV, and the anaerobic-anoxic reaction zone is aerated every 4h. The redox potential of the aerobic reaction zone is controlled at +200mV to +400mV. When the sludge concentration is ≥10000mg / L, sludge is discharged and the sludge concentration is controlled to remain stable.

[0071] The domesticated salt-tolerant activated sludge was used to treat biomedical wastewater with a salinity of 3%. The other parameters of the wastewater were CODcr 9700mg / L, total nitrogen 80mg / L, and total phosphorus 8mg / L. After adding the domesticated salt-tolerant activated sludge, on the 8th day of treatment, the influent CODcr was 2700mg / L, and the CODcr removal rate was stable at about 72.1%. The MLVSS of the sludge was 5.1g / L at the beginning of domestication, and after a period of time, its value finally stabilized at 7g / L, indicating that the sludge gradually adapted to the high-salinity wastewater, and its volatile components increased significantly, and the concentration of volatile activated sludge (MLVSS) increased by 37.3%.

[0072] Example 2

[0073] The salt-tolerant activated sludge acclimation method provided in this embodiment uses the acclimation equipment in Example 1, and the specific steps are as follows:

[0074] Fresh sludge is added into the above-mentioned acclimation device. The fresh sludge is taken from the biochemical sludge concentration tank of the sewage treatment station of the food processing plant. The sludge moisture content is 98% to 99%; VSS / TSS≥0.8±0.1; SVI is 85 to 150. At this time, the initial salt concentration of the system is 0.5%, MLSS is 6000mg / L, and CODcr is 3500mg / L. After about 10 days of acclimation, when the influent CODcr is 5000mg / L (carbon source prepared with glucose), the CODcr removal rate is about 95%, and the sludge sedimentation performance is good.

[0075] At this time, the inlet salinity is controlled to be 5%, CODcr 3500mg / L, ammonia nitrogen 80mg / L, and total phosphorus 15mg / L. The salt content is prepared by adding sodium chloride and sodium sulfate, and the CODcr / SO 4 2- ≤10, wherein CODcr is prepared by carbon source of biomedical wastewater (without refractory organic matter): external glucose carbon source in a ratio of 4:1, and the parameters of biomedical wastewater are CODcr 6000-8000 mg / L, total nitrogen 70-100 mg / L, total phosphorus 10-15 mg / L, and salt 2.5%. In this embodiment, ammonia nitrogen is regulated by adding urea, and total phosphorus is regulated by adding potassium dihydrogen phosphate.

[0076] When 5% salinity is introduced into the acclimatization device, the CODcr removal rate drops to 30% by taking the following measures:

[0077] The aerobic reactor increases the addition of external carbon source, nitrogen source and phosphorus source to make the CODcr:N:P in the system reach 100:5:1~150:5:1; the aerobic reactor increases the aeration volume and the dissolved oxygen reaches 5~6mg / L; the anaerobic reactor increases the addition of external carbon source, nitrogen source and phosphorus source to make the CODcr:N:P in the system reach 200:5:1~300:5:1; the sludge return from the aerobic reactor to the anaerobic-anoxic reactor is increased, and the return ratio is controlled at 100%~200%; depending on the MLVSS / MLSS ratio, fresh sludge from the outside is added and the inactivated sludge is replaced at the same time, the proportion of newly added sludge reaches 1 / 5~1 / 3, and the proportion of discharged inactivated sludge reaches 1 / 5~1 / 4, so that MLVSS / MLSS≥0.8, after about 15~20 days of adaptation, the CODcr removal rate rises to 75%.

[0078] The concentration of CODcr is gradually increased, and each gradient increase requires an adaptation period of about 5 to 7 days. In this embodiment, each gradient is an increase of 500 mg / L CODcr concentration. CODcr is formed by a 4:1 ratio of biomedical wastewater carbon source to an external glucose carbon source. The higher the influent CODcr concentration, the longer the required acclimatization period. The redox potential of the anoxic reaction zone is controlled at -100mV to +100mV, and the anaerobic-anoxic reaction zone is aerated every 6 hours. The redox potential of the aerobic reaction zone is controlled at +200mV to +400mV. When the sludge concentration is ≥12000mg / L, sludge is discharged and the sludge concentration is controlled to remain stable.

[0079] At the end of the domestication, the influent CODcr was 10000mg / L, and the CODcr removal rate was stable at about 70.5%. The MLVSS of the sludge was 5.1g / L at the beginning of the domestication. After a period of domestication, its value finally stabilized at 8.4g / L, indicating that the sludge gradually adapted to the high-salt wastewater and its volatile components increased significantly. From the initial stage of domestication to the final test period, the concentration of volatile activated sludge (MLVSS) increased by 64.7%, indicating that after a long period of domestication, microorganisms can grow and reproduce in wastewater with high salt content. Although the direct domestication method in a high-salt environment is subject to a large salinity shock in the early stage, it can eventually domesticate activated sludge that adapts to the high-salt environment, and the time used is relatively short, with an overall domestication time of 80 to 90 days.

[0080] Example 3

[0081] In this example, the salt-tolerant activated sludge obtained by domestication in Example 2 was transferred to another chemical and pharmaceutical wastewater with a salinity of 5%. The parameters of the wastewater were CODcr 9500mg / L, total nitrogen 60mg / L, total phosphorus 5mg / L, and salinity 5.1%. On the 12th day of treatment, the influent CODcr was 2800mg / L, and the CODcr removal rate was stabilized at about 70.5%. The MLVSS of the sludge was 7.2g / L at the beginning of domestication, and after a period of domestication, its value finally stabilized at 8.9g / L, indicating that the sludge gradually adapted to the high-salt wastewater and its volatile components increased significantly. The concentration of volatile activated sludge (MLVSS) increased by 23.6%, indicating that the salt-tolerant activated sludge obtained by domestication in this application has a strong adaptability to the fluctuation of high-salt wastewater.

[0082] Example 4

[0083] In this example, the salt-tolerant activated sludge obtained by acclimation in Example 1 was transferred into fine chemical wastewater with a salinity of 4%. The parameters of the wastewater were CODcr 9600 mg / L, total nitrogen 110 mg / L, total phosphorus 30 mg / L, and salinity 4%.

[0084] On the 15th day of treatment, the influent CODcr was 3100 mg / L, and the CODcr removal rate was stable at about 67.7%. The MLVSS of the sludge was 7 g / L at the beginning of domestication, and after a period of time, its value finally stabilized at 8.5 g / L, indicating that the sludge gradually adapted to the high-salt wastewater and its volatile components increased significantly. The concentration of volatile activated sludge (MLVSS) increased by 21.4%, indicating that the salt-tolerant activated sludge obtained by domestication in this application has good genetics.

[0085] Example 5

[0086] This embodiment is basically the same as embodiment 1, except that about 0.01 kg / m 3 Powdered activated carbon promotes the coagulation of activated sludge.

[0087] On the fifth day of treatment, the influent CODcr was 2600mg / L, and the CODcr removal rate was stable at about 73.2%. The MLVSS of the sludge was 5.1g / L at the beginning of acclimatization, and after a period of time, its value finally stabilized at 7.2g / L, indicating that the sludge gradually adapted to the high-salinity wastewater, its volatile components increased significantly, and the concentration of volatile activated sludge (MLVSS) increased by 41.2%.

[0088] Comparative Example 1

[0089] This comparative example is basically the same as Example 1, except that the concentration of acclimated salt in the system is 7%.

[0090] In the domestication method of this comparative example, due to the high salt concentration, a large number of activated sludge died. The MLVSS of the sludge was 4.8g / L at the beginning of domestication, and then quickly dropped to 1g / L. After multiple additions of fresh sludge, the concentration of volatile activated sludge (MLVSS) was still lower than 1.2g / L, and the CODcr removal rate was lower than 15%, indicating that when the salt concentration is too high, it is difficult to cultivate the activated sludge in salt-tolerant condition.

[0091] Comparative Example 2

[0092] This comparative example is basically the same as Example 1, except that the CODcr concentration gradient is gradually increased by 2000 mg / L.

[0093] In the acclimation method of this comparative example, since the gradient was set too high, when the CODcr increased from the initial CODcr 3500mg / L to 5500mg / L, the MLVSS of the sludge decreased from 5.1g / L to 4.8g / L, and then the MLVSS of the sludge was increased to 5.4g / L, the CODcr removal rate reached 75%, and the adaptation period was extended to more than 20 days by increasing nutritional supplements, adding fresh sludge, discharging inactivated sludge, and optimizing acclimation conditions. When the CODcr increased from 5500mg / L to 7500mg / L, the MLVSS of the sludge decreased again to 4g / L, and then it was restored to 5g / L, the CODcr removal rate reached 65%, and the adaptation period was about 25 days by increasing nutritional supplements, adding fresh sludge, discharging inactivated sludge, and optimizing acclimation conditions. This indicates that in a high-salinity environment, sludge is more sensitive to large-scale fluctuations in CODcr, the sludge adaptation period is increased, the sludge proliferation is restricted by both high salt and high CODcr factors, and the difficulty of sludge domestication increases.

Claims

1. A method for acclimatizing salt-tolerant activated sludge, characterized in that: Includes steps: S1. Add fresh sludge into the acclimation device, wherein the moisture content of the fresh sludge is 98% to 99%, VSS / TSS ≥ 0.8 ± 0.1, and SVI is 85 to 150; the acclimation device comprises an anaerobic-anoxic reaction zone and an aerobic reaction zone which are interconnected, and at the beginning of acclimation, the sludge concentration MLSS is controlled at 5000 to 6000 mg / L; S2, control the salt concentration in the system to 3-5%, when CODcr removal rate ≤30%, through Adding more nutrients to the acclimation device so that the proportion of the added carbon source reaches 1 / 4 to 1 / 5; and / or, Increase the aeration volume in the aerobic reaction zone to make the dissolved oxygen in the aerobic reaction zone reach 5-6 mg / L; and / or, Returning the sludge from the aerobic reaction zone to the anaerobic-anoxic reaction zone, with the return ratio controlled at 100% to 200%; and / or, Add fresh sludge, with the new sludge dosage accounting for 1 / 5 to 1 / 3; and / or, Discharge of inactivated sludge, the amount of inactivated sludge discharged accounts for 1 / 5 to 1 / 4, until the CODcr removal rate is ≥ 75%; S3. Increase CODcr concentration gradient gradually with a gradient of 500-1000 mg / L. The acclimatization period of each CODcr concentration gradient is 5-10 days. Control the sludge age for 20-25 days. When the sludge concentration is ≥10000-12000 mg / L, discharge the sludge and control the sludge concentration to remain stable. When the influent CODcr is ≥10000 mg / L and the removal rate is ≥70%, the acclimation is terminated to obtain the salt-tolerant activated sludge.

2. The method for acclimating salt-tolerant activated sludge according to claim 1, characterized in that: The method used to control the salt concentration in the system is to add salts; the salts are sodium chloride and sodium sulfate, and the concentration is controlled to be 3≤CODcr / SO4 2- ≤10.

3. The method for acclimating salt-tolerant activated sludge according to claim 1, characterized in that: The increased nutrient addition comprises: the carbon source is the wastewater carbon source and glucose in a mass ratio of 4:1 to 5:1; and the CODcr:N:P is 100:5:1 to 300:5:

1.

4. The method for acclimating salt-tolerant activated sludge according to claim 3, characterized in that: The wastewater carbon source is a biomedical wastewater carbon source and does not contain degradable organic matter; the fresh sludge is taken from a biochemical sludge concentration tank of a food processing plant sewage treatment station.

5. The method for acclimating salt-tolerant activated sludge according to claim 1, characterized in that: The redox potential of the anoxic reaction zone is controlled within a range of -100 mV to +100 mV; and the redox potential of the aerobic reaction zone is controlled within a range of +200 mV to +400 mV.

6. The method for acclimating salt-tolerant activated sludge according to claim 1, characterized in that: The anaerobic-anoxic reaction zone is aerated every 4 to 6 hours.

7. The method for acclimating salt-tolerant activated sludge according to any one of claims 1 to 6, characterized in that: A flocculant is added into the aerobic reaction zone.

8. Salt-tolerant activated sludge acclimatization device, characterized by: A method for taming salt-tolerant activated sludge according to any one of claims 1 to 7, wherein the taming device comprises: an anaerobic-anoxic reactor (1) and an aerobic reactor (2); The upper parts of the anaerobic-anoxic reactor (1) and the aerobic reactor (2) are connected via a pipeline (10); The lower parts of the anaerobic-anoxic reactor (1) and the aerobic reactor (2) are connected via a sludge return pipe (14), and the sludge return pipe (14) is also connected to a sludge return pump (15); The bottoms of the anaerobic-anoxic reactor (1) and the aerobic reactor (2) are both provided with microporous aerators (4); The anaerobic-anoxic reactor (1) is provided with a fluidized bed filler (3); The aerobic reactor (2) is provided with a stirrer (7); The aerobic reactor (2) is provided with a mud discharge port (6).

9. The salt-tolerant activated sludge acclimation device according to claim 8, characterized in that: The fluidized bed filler (3) accounts for ≥60% of the volume of the anaerobic-anoxic reactor (1).

10. The salt-tolerant activated sludge acclimation device according to claim 8, characterized in that: The height-to-diameter ratios of the anaerobic-anoxic reactor (1) and the aerobic reactor (2) are both 2.5-5.

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