A method for activating unstable algae-bacteria granular sludge

Abstract

A method for activating unstable algae-bacteria granular sludge belongs to the field of water treatment technology and overcomes the defect of poor restart effect of ABGS (algae-bacteria granular sludge) in the prior art after long-term storage at room temperature. A method for activating unstable algae-bacteria granular sludge comprises: adding unstable algae-bacteria granular sludge, adding functional bacteria that can secrete AHLs into the influent, and running until the edge of the algae-bacteria granular sludge is compacted and SVI is stable. 30 The addition of functional bacteria is stopped when the nitrogen and phosphorus removal rates are both above 80% and the concentration is ≤40mL / g. The unstable algae-bacteria granular sludge is obtained by allowing algae-bacteria granular sludge to stand at room temperature for more than six months after stable operation for more than 100 days. The functional bacteria are screened and expanded during the cultivation of the stable algae-bacteria granular sludge. The method of the present invention can significantly reduce costs, does not cause secondary pollution to the environment, and has a faster recovery efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment, and in particular relates to a method for activating unstable algae-bacteria granular sludge. Background Art

[0002] Aerobic granular sludge (AGS) is a recently emerging wastewater biological treatment process with promising application prospects. It offers numerous advantages, including excellent settling performance, high sludge activity, high biomass density, and strong shock resistance. Microalgae possess advantages such as high photosynthetic rates, rapid reproduction, strong environmental adaptability, and efficient nitrogen and phosphorus treatment. Some microalgae exhibit strong chemoheterotrophic and mixotrophic capacities, directly utilizing certain organic matter in wastewater to synthesize their own cellular biomass. Combining the respective strengths of AGS and microalgae, a novel algal-bacterial granular sludge (ABGS) wastewater treatment technology has been developed. This technology addresses the problem of poor microalgae settling performance while also enabling the carbon dioxide produced by bacterial metabolism to be utilized by microalgae for photosynthesis, contributing to the oxygen cycle within the ABGS microenvironment. This reduces system energy consumption, such as the external oxygen supply, and, to a certain extent, contributes to the reduction of greenhouse gas emissions, such as CO2, from wastewater treatment plants.

[0003] Certain bacteria in sewage sludge systems secrete a variety of quorum sensing signaling molecules, which transmit instructions and information. Acylated homoserine lactones (AHLs) are among the earliest discovered, fully characterized, and currently the most comprehensively studied class of signaling molecules. They are crucial for the formation and stability of AGS, manifesting in promoting microbial activity, secretion of extracellular polymeric substances (EPS), and bacterial aggregation. Because EPS adheres to microbial surfaces, it is a key determinant of microbial surface properties. Signaling molecules can alter microbial surface properties by regulating EPS synthesis, further influencing particle formation and decomposition. Studies have shown that AHLs can promote the synthesis of EPS components such as tryptophan and proteins, thereby increasing the hydrophobicity of microbial surfaces. Furthermore, AHLs have been shown to affect algal physiological properties, with bacterial secretion of AHLs promoting microbial growth. Therefore, quorum sensing mediated by AHLs is crucial for the structural integrity of AGS and the maintenance of the bacterial-algal symbiotic relationship.

[0004] The complete granulation of ABGS takes a long time, and this process generates high energy consumption, thus limiting the development of this new sewage treatment technology. Cryopreservation is currently a common method for storing granular sludge. Current research on the reactivation of ABGS after storage includes exploring the storage of sludge at low temperatures (4 degrees or -20 degrees) for half a year or short-term storage at room temperature before restarting. However, low-temperature storage of granular sludge will incur time and energy costs and is inconvenient to operate. At the same time, the significant reduction in pollutant removal efficiency will also cause certain difficulties for restarting; the recovery effect after short-term storage at room temperature is better, but if the storage time is not long, it is not conducive to the application of actual projects. If the existing technology is used to store at room temperature for a long time and then restart, the particle morphology will not recover well and the pollutant removal efficiency will be low. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defect in the prior art that ABGS has poor restarting effect after long-term storage at room temperature, thereby providing a method for activating unstable algae-bacteria granular sludge.

[0006] To this end, the present invention provides the following technical solutions.

[0007] A method for activating unstable algae-bacteria granular sludge, comprising: adding unstable algae-bacteria granular sludge, adding functional bacteria capable of secreting AHLs into the influent, and running the process until the edges of the algae-bacteria granular sludge are compacted and SVI is 30 Stop adding functional bacteria when the removal rate of ammonia nitrogen and total phosphorus is above 80%;

[0008] The unstable algae-bacteria granular sludge is sludge obtained by allowing the algae-bacteria granular sludge to stand at room temperature for more than half a year after stable operation for more than 100 days;

[0009] The functional bacteria are screened out during the process of cultivating the stably operating algae-bacteria granular sludge and then expanded and cultured.

[0010] The edge compaction of algae-bacteria granular sludge means that there are no filamentous bacteria on the edges of more than 80% of the algae-bacteria granular sludge.

[0011] Furthermore, the steps of screening functional bacteria include:

[0012] Step 1: Cultivating algae-bacteria granular sludge and regularly measuring the concentration of AHLs;

[0013] Step 2: The mud-water mixture at the time of the highest AHLs concentration is crushed and enriched for culture to isolate bacteria;

[0014] Step 3: Select various bacteria with obvious morphological differences and culture them to obtain different strains;

[0015] Step 4: inoculating the different strains obtained in step 3 into liquid culture medium for enrichment, taking the supernatant, and adding acid to the supernatant for acidification;

[0016] Step 5: Add the acidified supernatant to the culture medium containing the biosensor to screen out functional bacteria that can secrete AHLs.

[0017] Furthermore, step 5 also includes biological identification of the screened functional bacteria to ensure accuracy.

[0018] Furthermore, after the functional bacteria are screened out, they are expanded and cultured separately, and the bacterial solutions of the expanded and cultured functional bacteria in the logarithmic phase are mixed in a certain proportion to obtain a mixed biological bacterial solution, and a certain amount of the mixed biological bacterial solution is added to the influent water;

[0019] Preferably, 8 to 10 functional bacteria that secrete high concentrations of AHLs are selected and cultured separately.

[0020] Furthermore, bacterial suspensions of various functional bacteria in logarithmic phases were mixed in equal volumes.

[0021] Furthermore, in step 1, the cultivation of algae-bacteria granular sludge satisfies at least one of the following conditions:

[0022] (1) The inoculated sludge used was the sludge from the aerobic tank of the municipal sewage treatment plant;

[0023] (2) The initial sludge concentration in the reactor immediately after the inoculated sludge was added was 3000-5000 mg / L;

[0024] (3) The COD of the influent is 200-250 mg / L, NH4 + -N is 18-25 mg / L, TP is 3-3.5 mg / L;

[0025] (4) The inlet water temperature used was 25 ± 2 °C and the pH was 7.5 ± 0.5;

[0026] (5) Light intensity is 40-120 μmol / m 2 ·s, photoperiod is 12h / 12h or 6h / 18h;

[0027] (6) The reactor operation mode is anaerobic / aerobic / anoxic.

[0028] Furthermore, the reactor operation cycle is 6-8h;

[0029] Preferably, the operation cycle is to allow water to flow in for 2 to 5 minutes, without aeration after the water is introduced, and to first operate in an anaerobic state for 2 to 3 hours, and then operate in an aerobic state for 90 to 120 minutes after aeration, and finally turn off the aeration and operate in an anoxic state for a period of time, and then settle for 2 to 15 minutes, and then discharge the water for 5 to 10 minutes;

[0030] Preferably, the aeration flow rate is 100-150 mL / min. The operation cycle refers to a cycle from water inlet to water outlet.

[0031] Furthermore, in step 5, the culture medium containing the biosensor includes a plate containing A136 bacterial solution and a plate containing CV026 bacterial solution.

[0032] Furthermore, the OD of the mixed biological bacterial solution 600 Controlled at 0.8-1.

[0033] Furthermore, the volume ratio of the dosage of the mixed biological bacteria liquid to the water intake is between 1 / 1000 and 1 / 500.

[0034] Furthermore, the AHLs signaling molecules secreted by the bacteria themselves during the cultivation of algae-bacteria granular sludge in step 1 include C6-HSL, 3OC12-HSL, C8-HSL and C12-HSL.

[0035] Furthermore, the AHLs concentration was determined by filtering a certain amount of the mud-water mixture, extracting the filtered aqueous phase, removing the solvent from the extract, and measuring the AHLs concentration using a liquid chromatograph coupled with a triple quadrupole mass spectrometer. AHLs concentration was highest before bacterial granulation (the first 50 days of initiation) and then decreased during the mature phase.

[0036] Furthermore, the culture medium used for separating and screening functional bacteria is LB solid culture medium, and the culture medium used for expanding and culturing functional bacteria is LB culture medium.

[0037] Furthermore, in step 1, an intermittent SBR reactor is used to culture the algae-bacteria granular sludge, and 1 to 3 glue-filled waterproof LED hard light strips are arranged outside the reactor to control the light intensity. The light strips are wrapped with tin foil to prevent interference from the surrounding environment.

[0038] Furthermore, the SVI of step 1 30 (Sludge volume index) is 40-120mL / g.

[0039] Furthermore, in step 1, the volume exchange ratio (the ratio of the water output in each cycle to the limited volume of the entire reactor) is 50%, and the hydraulic retention time (HRT) is 12-16 hours.

[0040] Preferably, in step 2, 100-200 mL of the sludge-water mixture is taken during the period when the AHLs concentration is highest during the cultivation of algae-bacteria granular sludge.

[0041] Preferably, the method for preparing a plate containing A136 bacterial liquid comprises: under sterile conditions, activating Agrobacterium tumefaciens A136 overnight in LB medium containing 3-5 mg / mL tetracycline and 5-20 mg / mL spectinomycin; then mixing the overnight activated Agrobacterium tumefaciens A136 bacterial liquid with LB medium containing 5-10 mg / L 5-bromo-4-chloro-3-indole-β-D-galactoside (X-gal), spreading the mixture on a sterile culture dish, solidifying it to form a culture plate, and then punching the plate to form a plurality of circular wells with a diameter of 0.8-1 cm. The overnight activated Agrobacterium tumefaciens A136 bacterial liquid accounts for 10%-20% of the total volume of the overnight activated Agrobacterium tumefaciens A136 bacterial liquid + LB medium.

[0042] Preferably, the method for preparing a plate containing a CV026 bacterial solution comprises: under sterile conditions, activating Chromobacterium violaceum CV026 overnight in LB medium containing 1-5 mg / mL kanamycin; then, mixing the activated Chromobacterium violaceum CV026 bacterial solution with the LB medium and spreading the solution on a sterile culture dish, allowing it to solidify to form a culture plate; and then punching the plate to form a plurality of circular wells with a diameter of 0.8-1 cm. The activated Chromobacterium violaceum CV026 bacterial solution accounts for 10% to 20% of the total volume of the activated Chromobacterium violaceum CV026 bacterial solution + LB medium.

[0043] Biosensor Principle: In the presence of AHLs with carbon chain lengths between 6 and 14, Agrobacterium tumefaciens A136 hydrolyzes X-gal, causing a visual blue appearance. When the culture supernatant of the test strain is added to a culture plate containing Agrobacterium tumefaciens A136 and X-gal, a blue color is produced, indicating that the test strain has the ability to secrete AHLs. The presence of AHLs with carbon chain lengths between 4 and 8 induces quorum sensing in Chromobacterium violaceum CV026 to produce violacein. When the culture supernatant of the test strain is co-cultured with Chromobacterium violaceum CV026, a purple color is produced, indicating that the test strain has the ability to secrete AHLs.

[0044] The signs of successful recovery are dark green sludge color, increased sludge particle size, tight edge structure of most particles, SVI 30 ≤40mL / g, COD, ammonia nitrogen and total phosphorus removal rates>70%.

[0045] The technical solution of the present invention has the following advantages:

[0046] 1. The activation method of the unstable algae-bacteria granular sludge of the present invention comprises: adding unstable algae-bacteria granular sludge, adding functional bacteria capable of secreting AHLs into the influent, and running until the edge of the algae-bacteria granular sludge is compacted and SVI is 30 The addition of functional bacteria is stopped when the removal rates of ammonia nitrogen and total phosphorus are both above 80% and the destabilized algae-bacteria granular sludge is sludge obtained by allowing algae-bacteria granular sludge that has been stably operated for more than 100 days to stand at room temperature for more than half a year; the functional bacteria are screened out during the process of culturing the stably operated algae-bacteria granular sludge and are expanded and cultured.

[0047] ABGS stored at room temperature for a long time can be domesticated through quorum sensing of functional bacteria that can secrete AHLs signal molecules, and the activated sludge can be reused as inoculum sludge for cultivating ABGS, which is of great significance for the rapid start-up and batch-scale application of ABGS.

[0048] This method screens for functional bacteria during the existing culture of stable algae-bacteria granular sludge, significantly reducing costs. Furthermore, both the unstable algae-bacteria granular sludge and the screened functional bacteria originate from the system itself, and their addition to the algae-bacteria system does not cause secondary environmental pollution. Furthermore, this method increases the biodiversity of the system and provides faster recovery efficiency than directly adding signal molecules.

[0049] The method of the present invention can quickly produce structurally stable ABGS with a high removal rate. This not only reduces the storage cost of algae-bacteria granular sludge, but also addresses the need for mature ABGS commercialization in practical projects. Furthermore, the method is easy to operate, and the materials are sourced from the system itself, without causing secondary pollution to the environment.

[0050] 2. The activation method of unstable algae-bacteria granular sludge provided by the present invention is to regularly extract signal molecules and measure the concentrations of different types during the cultivation of algae-bacteria granular sludge, and perform correlation analysis with the sludge characteristics of ABGS (the experimental data were analyzed by SPSS21.0. The correlation between objects was analyzed by correlation analysis and Pearson test (levels included complete positive correlation r=1 and complete negative correlation r=-1). The difference between objects was analyzed by One-way ANOVA (levels included significant p<0.05 and extremely significant p<0.01). The results showed that the detected signal molecules C6-HSL, C8-HSL, 3OC12-HSL and C12-HSL were significantly positively correlated with the average sludge particle size and EPS synthesis (p<0.01). The action mechanism of AHLs signal molecules in the formation and maturation of ABGS can be clarified. In this process, functional bacteria that can secrete signal molecules are screened and prepared into a bacterial solution and added to the unstable ABGS system, which can quickly restore the disintegrated granular sludge to its original state and effectively shorten the restart time of ABGS.

[0051] 3. The activation method of unstable algae-bacteria granular sludge provided by the present invention takes the mud-water mixture when the AHLs concentration is the highest, and the functional bacteria screened out have stronger ability to secrete signal molecules, more types, higher concentrations, and stronger group response. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0053] Figure 1 Figure 1 is a diagram of the ABGS culture device;

[0054] Figure 2 The microscopic morphology of ABGS after 180 days of static storage (magnification 40 times);

[0055] Figure 3 This is a photo of ABGS after 50 days of restoration using the method of Example 1;

[0056] Figure 4 This is a photo of ABGS after 50 days of restoration using the method of Comparative Example 1;

[0057] Figure 5 The changes of ammonia nitrogen concentration in different implementation methods before standing and during the recovery stage;

[0058] Figure 6The changes of total phosphorus concentration before standing and in different implementation methods during the recovery stage;

[0059] Figure 7 This is the microscope morphology of ABGS before standing (magnification 40 times). DETAILED DESCRIPTION

[0060] The following examples are provided for a better understanding of the present invention and are not intended to limit the best mode of implementation. They do not limit the content and scope of protection of the present invention. Any product identical or similar to the present invention obtained by anyone under the guidance of the present invention or by combining the features of the present invention with other prior arts shall fall within the scope of protection of the present invention.

[0061] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in this field can be used. If the manufacturer of the reagents or instruments is not specified, they are all commercially available conventional reagents.

[0062] Example 1

[0063] This embodiment provides a method for activating unstable algae-bacteria granular sludge, comprising the following steps:

[0064] (1) Cultivate stably operating algae-bacteria granular sludge, screen functional bacteria that can secrete AHLs during the cultivation process, and expand the culture.

[0065] Step 1: Cultivate algae-bacteria granular sludge and regularly measure the concentration of AHLs in the system during the cultivation process:

[0066] Devices for cultivating algae-bacteria granular sludge such as Figure 1 As shown, a columnar SBR reactor made of organic glass is used, with an inner diameter of 10 cm, a height of 32 cm, and an effective volume of 2.3 L. The outside of the reactor is tied with an LED light strip, and the light intensity is 40.7±1.8μmol / m 2s, with a photoperiod of 12 h / 12 ​​h. The reactor operated in an A / O / A (anaerobic / aerobic / anoxic) mode, with only agitation provided in the anaerobic section at a rate of approximately 250 rpm. The operating cycle was 6 h, with four cycles per day. Each cycle consisted of a 2-min water inlet, followed by no aeration, 120 min of anaerobic operation, 90 min of aerobic operation after aeration, and finally 123-136 min of anoxic operation with aeration turned off, followed by 2-15 min of settling, and 10 min of effluent. The volume exchange ratio was 50%, and the hydraulic retention time (HRT) was 12 h. Aeration was achieved via a bottom aerator with an aeration flow rate set at 100 mL / min. The reactor's inlet, agitation, aeration, effluent, and illumination were all connected to microcomputer-controlled switches to maintain normal operation. The inlet water used simulated domestic sewage, with an inlet temperature of 25 ± 2°C and a pH of 7.5 ± 0.5.

[0067] The inoculum sludge used to culture algae-bacteria granular sludge was taken from the aerobic tank of Wuhan Longwangzui Wastewater Treatment Plant. The sludge was flocculent and yellow-brown in color. After the sludge was taken back, it was first air-dried for 1 day and then acclimated with artificial simulated domestic sewage for one week. The initial MLSS in the reactor after adding the inoculum sludge was 3700 mg / L, MLVSS (mixed liquor volatile suspended solids concentration) was 1530 mg / L, and SVI was 1000 mg / L. 30 It is 92.17mL / g.

[0068] Artificial simulated domestic sewage: COD 220mg / L (sodium acetate), NH4 + -N 20mg / L (ammonium chloride), TP 3mg / L (potassium dihydrogen phosphate), Mg 2+ 10mg / L (magnesium sulfate), Ca 2+ 10mg / L (calcium chloride), 1mL / L trace element solution. The trace element solution consists of 0.9mg / L ferric chloride, 0.15mg / L boric acid, 0.18mg / L potassium iodide, 0.03mg / L copper sulfate pentahydrate, 0.06mg / L manganese chloride tetrahydrate, 0.12mg / L zinc sulfate heptahydrate, 0.15mg / L cobalt chloride hexahydrate, 0.06mg / L sodium molybdate dihydrate, and 10mg / L ethylenediaminetetraacetic acid.

[0069] The method for measuring the concentration of AHLs in the culture system during the incubation process includes: 200 mL of the sludge-water mixture from the reactor is filtered through a 0.45 μm filter flask. The filtered aqueous phase is then extracted twice with equal volumes of acidified ethyl acetate (0.1% acetic acid). The combined ethyl acetate extracts from the two extractions are stored at -20°C until use. The solvent is removed from the ethyl acetate layer using a rotary evaporator and nitrogen purge. The residue is redissolved in 1 mL of chromatographic-grade methanol and collected in a liquid phase vial for analysis. Liquid chromatography coupled with a triple quadrupole mass spectrometer is used to quantitatively detect multiple signal molecules. Results indicate that four AHL-like signal molecules, C6-HSL, C8-HSL, C12-HSL, and 3OC12-HSL, were detected in the reactor sludge-water mixture. Determining the types of signal molecules present in the reactor allows for the determination of specific screening methods.

[0070] Step 2: Take a certain amount of mud-water mixture during the period when the total concentration of AHLs in the reactor is the highest, crush the mud-water mixture, and then enrich and culture it. Then, dilute it in a gradient manner on a solid culture medium to separate the bacteria:

[0071] Enrichment culture: While measuring the AHLs concentration in the sludge-water mixture in the reactor, collect granular sludge (ABGS) during the anoxic phase at the same time. Select the ABGS during the period with the highest AHLs concentration, wash it three times with sterile phosphate buffer solution, then add an equal volume of sterile PBS solution and place it in a conical flask for shaking culture. Place a few glass beads in the conical flask to break up the sludge flocs, which facilitates the release of bacteria from the sludge sample. After shaking for 2 hours, let it stand for 10 minutes. Take 20mL of the supernatant and enrich it in a sterile culture medium containing the same influent components as the ABGS. Place it in a constant temperature shaking incubator at 25°C and 150 rpm until the culture medium becomes turbid. Repeat this step three times to ensure that the bacterial concentration reaches a high level.

[0072] Sterile PBS solution was diluted graded (10 -3 , 10 -4 , 10 -5 ) and plated on solid culture medium.

[0073] Step 3: Select bacteria with obvious morphological differences (bacteria of different genera) from the solid culture medium and inoculate them onto new solid culture medium and repeat the streak culture three times to obtain different strains:

[0074] Select bacteria with obvious morphological differences from the plate and inoculate them on a new solid culture medium for multiple streak culture. Place the culture medium in a biochemical incubator with the same external conditions as the reactor until the line shape is clear and the tail is distributed in multiple points.

[0075] Step 4: Inoculate the different strains obtained in step 3 into liquid culture medium for enrichment, take the supernatant, and add acid to the supernatant for acidification:

[0076] The isolated bacteria were inoculated into LB liquid culture medium at a ratio of 1% of the culture medium volume and cultured at 37°C and 150 rpm until the OD 600 =0.3. A small amount of bacterial solution was centrifuged (4°C, 5000 rpm) for 15 min, the supernatant was collected and acidified by adding acetic acid, the mass concentration of acetic acid being 1%.

[0077] Step 5: Add the acidified supernatant to the culture medium containing the biosensor, screen out the functional bacteria that can secrete AHLs, and perform bioassay on the functional bacteria.

[0078] Based on the results of the AHL signaling molecule assay in step 1, a flat-plate sensor containing an Agrobacterium tumefaciens A136 bacterial suspension was prepared. The preparation steps were as follows: Under sterile conditions, Agrobacterium tumefaciens A136 was activated overnight in LB medium containing 5 mg / mL tetracycline and 10 mg / mL spectinomycin. The overnight activated A136 suspension was then mixed with LB medium containing 10 mg / L X-gal and spread onto a sterile Petri dish before cooling to form a culture plate. The overnight activated A136 suspension accounted for 20% of the total volume of the overnight activated A136 suspension plus the LB medium containing 10 mg / L X-gal. Several circular wells with a diameter of 0.8 cm were then punched into the plate. 50 μL of the acidified supernatant was inoculated into each of these wells. After the plates are placed in an incubator and cultured for 24-36 hours, when blue pigment appears on the culture plates, it indicates that the culture supernatant of the strain responds to the Agrobacterium tumefaciens A136 bacterial solution. This indicates that the strain has the ability to produce AHLs and has a quorum sensing effect. At the same time, the response time for each strain to produce blue is recorded.

[0079] Biological identification of AHLs-secreting bacteria: All bacteria with quorum sensing effects are subjected to 16srRNA sequencing to identify their species.

[0080] Select a variety of strains with large blue areas and short response times in the circular holes for inoculation into LB liquid culture medium for expansion culture, and then evenly mix the above bacterial solutions in the logarithmic growth phase in equal volumes. 600 Control to 1 to obtain mixed biological bacterial liquid.

[0081] (2) Activate unstable algae-bacteria granular sludge.

[0082] (1) The mature ABGS (average sludge particle size > 1 mm, NH4+ -N, COD, TP removal rates are all above 80%) and stored at room temperature without external light for more than half a year to obtain unstable algae-bacteria granular sludge. The microscopic morphology of mature ABGS before standing after stable operation for more than 100 days is shown in the figure below. Figure 7 shown.

[0083] (2) The unstable algae-bacteria granular sludge after standing is placed in an SBR reactor. The operating conditions and influent formula of the SBR reactor remain consistent with those described in (1).

[0084] The sludge SOUR (Specific Oxygen Consumption Rate), settling performance, particle morphology, and inlet and outlet water quality in the two reactors were monitored on the first day after restart. The results showed that the sludge SOUR value decreased by more than 50% compared with the previous stable period, the sludge color turned black, and the presence of microalgae was almost undetectable. At the same time, many particles were observed to disintegrate, the content of flocculent sludge increased significantly, and some particles had loose structures and were in the form of thin strips. The sludge morphology under an electron microscope was as follows: Figure 2 As shown in the figure, the sludge settling performance decreased significantly, SVI 30 Increased to 95mL / g. NH4 + The -N removal rate dropped from over 90% to below 70%, and the TP removal rate was negative. The system was operating in very poor condition.

[0085] The mixed biological bacterial liquid prepared in (I) is combined with the artificial simulated domestic sewage in (I) step 1 in a certain ratio (v / v is 1 / 500), and is used as the influent after the reactor is restarted and continuously operated for a period of time.

[0086] Real-time monitoring of sludge morphology, chlorophyll concentration, and effluent carbon, nitrogen, and phosphorus concentrations in the reactor.

[0087] Example 2

[0088] This embodiment is basically the same as embodiment 1, except that the mixed biological bacterial solution prepared in (I) and the artificial simulated domestic sewage in step 1 of (I) are combined in a certain ratio (v / v is 1 / 800).

[0089] Comparative Example 1

[0090] This comparative example is basically the same as Example 1, except that in this comparative example (II) (2), no mixed biological bacterial solution is added to the influent water, and only an LB liquid culture medium equal to the mixed biological bacterial solution in Example 1 is added.

[0091] Comparative Example 2

[0092] This comparative example is basically the same as Example 1, except that, in this comparative example (II) (2), no mixed biological bacteria liquid is added to the influent, but a purchased signal molecule mixture is added (the signal molecule mixture is an equal volume mixture of C6-HSL, C8-HSL, 3OC12-HSL and C12-HSL, and the concentration of the signal molecules in the influent containing signal molecules is 50 nmol / L. After the influent containing signal molecules at this concentration is subjected to a color development reaction with Agrobacterium tumefaciens, it is found that the color development area is consistent with that of the influent in the example, indicating that the concentration of the signal molecules in comparative example 2 is basically the same as that in Example 1).

[0093] The time for adding the mixed biological liquid or culture medium / signal molecule liquid in Examples 1 and 2 and Comparative Examples 1 and 2 was kept consistent. When the sludge morphology and the dirt removal rate of one embodiment returned to a stable state close to that before standing, the addition was stopped, that is, the embodiment with the fastest recovery was used as the benchmark.

[0094] The test results showed that the color of the sludge in Example 1 changed to light yellow after 5 days, at which time the COD removal rate had reached 80%, and returned to light green after 10 days. The chlorophyll a concentration was undetectable on the first day, but recovered to 1.33 mg / g·VSS on the 10th day. The MLSS increased from 2250 mg / L to 2685 mg / L, and the SVI of the sludge was 0. 30 The TP removal rate recovered to 40.15 mL / g. On the 15th day, the content of filamentous bacteria decreased significantly, the particle size increased significantly, and all particles under the microscope were complete in structure, with compact edges and dark green color. The TP removal rate recovered to more than 70% on the 20th day. The addition of mixed biological solution was stopped on the 25th day. At this time, the SVI of the sludge 30 Restore to 30mL / g, such as Figure 5 、 Figure 6 As shown in Figure 2, on the 25th day, the ammonia nitrogen and total phosphorus removal rates of Example 1 were both above 80%, and the reactor as a whole continued to operate in a good state. After stopping the addition of functional bacteria, the operating conditions after the addition of functional bacteria were continuously monitored. The algae-bacteria granular sludge activated by the present invention did not become unstable for a long time. The granule morphology on the 50th day was as follows: Figure 3 The concentration of the mixed biological liquid added in Example 2 is slightly lower than that in Example 1, and the effluent water quality recovery speed is slightly slower than that in Example 1. On the 35th day, it basically recovered to the level of the stable state before standing, but it is still better than Comparative Examples 1 and 2.

[0095] The reactor outlet water NH4 in Comparative Example 1 +The -N concentration did not return to its stable state before standing until the 35th day, while the TP took longer, nearly 50 days. In addition, free filamentous bacteria were still observed on the edges of some (more than 30%) particles at 50 days, and the supernatant was turbid. The sludge settling performance and pollutant removal rate were worse than those of the example. The particle morphology of the comparative example 1 on the 50th day was as follows: Figure 4 The effluent of Comparative Example 2 basically recovered to the level of the stable state before standing on the 40th day, which was still longer than that of Examples 1 and 2.

[0096] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for activating unstable algae-bacteria granular sludge, characterized in that: include: Add unstable algae-bacteria granular sludge and add functional bacteria that can secrete AHLs into the influent water, and keep running until the edge of the algae-bacteria granular sludge is compacted and SVI is 30 Stop adding functional bacteria when the removal rate of ammonia nitrogen and total phosphorus is above 80%; The unstable algae-bacteria granular sludge is sludge obtained by allowing the algae-bacteria granular sludge to stand at room temperature for more than half a year after stable operation for more than 100 days; The functional bacteria are screened out during the process of cultivating the stably operating algae-bacteria granular sludge and then expanded and cultured; The steps for screening functional bacteria include: Step 1: Cultivating algae-bacteria granular sludge and regularly measuring the concentration of AHLs; Step 2: The mud-water mixture at the time of the highest AHLs concentration is crushed and enriched for culture to isolate bacteria; Step 3: Select various bacteria with obvious morphological differences and culture them to obtain different strains; Step 4: inoculating the different strains obtained in step 3 into liquid culture medium for enrichment, taking the supernatant, and adding acid to the supernatant for acidification; Step 5: Add the acidified supernatant to the culture medium containing the biosensor to screen out functional bacteria that can secrete AHLs.

2. The activation method according to claim 1, characterized in that: Step 5 also includes biological identification of the screened functional bacteria.

3. The activation method according to claim 1 or 2, characterized in that: After the functional bacteria are screened out, they are expanded and cultured separately, and the logarithmic phase bacterial solutions of the expanded and cultured functional bacteria are mixed in a certain proportion to obtain a mixed biological bacterial solution, and a certain amount of the mixed biological bacterial solution is added to the influent water.

4. The activation method according to claim 3, characterized in that: After screening out the functional bacteria, 8 to 10 strains of functional bacteria that secrete high concentrations of AHLs are selected for expansion culture.

5. The activation method according to claim 3, characterized in that: Equal volumes of logarithmic-phase bacterial solutions of various functional bacteria were mixed.

6. The activation method according to claim 1 or 2, characterized in that: In step 1, the cultivation of algae-bacteria granular sludge satisfies at least one of the following conditions: (1) The inoculated sludge used was the sludge from the aerobic tank of the municipal sewage treatment plant; (2) The initial sludge concentration in the reactor immediately after the inoculated sludge was added was 3000-5000 mg / L; (3) The COD of the influent is 200-250 mg / L, NH4 + -N is 18-25 mg / L, TP is 3-3.5 mg / L; (4) The inlet water temperature used was 25 ± 2 °C and the pH was 7.5 ± 0.5; (5) Light intensity is 40-120 μmol / m 2 ·s, photoperiod is 12h / 12h; (6) The reactor operation mode is anaerobic / aerobic / anoxic.

7. The activation method according to claim 1 or 2, characterized in that: In step 1, the light intensity for culturing algae-bacteria granular sludge is 40-120 μmol / m 2 ·s, and the photoperiod was 6h / 18h.

8. The activation method according to claim 6, characterized in that: The reactor operation cycle is 6-8h.

9. The activation method according to claim 6, characterized in that: During the operation cycle, water is added for 2 to 5 minutes. After the water is added, no aeration is performed. The system first operates in an anaerobic state for 2 to 3 hours, and then operates in an aerobic state for 90 to 120 minutes after aeration. Finally, the aeration is turned off and the system operates in an anoxic state for a period of time, followed by sedimentation for 2 to 15 minutes and water discharge for 5 to 10 minutes.

10. The activation method according to claim 9, characterized in that: The aeration flow rate is 100-150 mL / min.

11. The activation method according to claim 1 or 2, characterized in that: In step 5, the culture medium containing the biosensor includes a plate containing A136 bacterial solution and a plate containing CV026 bacterial solution.

12. The activation method according to claim 3, characterized in that: The OD of the mixed biological bacterial solution 600 Controlled at 0.8-1.

13. The activation method according to claim 12, characterized in that: The volume ratio of the dosage of the mixed biological bacteria liquid to the water intake is between 1 / 1000 and 1 / 500.

Images