Method and application of cultivating microalgae-bacteria granular sludge based on Maotai-flavor liquor wastewater

Abstract

The present application relates to the field of sewage treatment, and specifically discloses a method for culturing microalgae-bacteria granular sludge based on Maotai-flavor liquor wastewater and its application. The method for culturing microalgae-bacteria granular sludge based on Maotai-flavor liquor wastewater comprises the following steps: step S1, taking activated sludge from a sewage treatment plant, aerating and screening to obtain pre-treated activated sludge; step S2, configuring simulated Maotai-flavor liquor wastewater; step S3, using simulated Maotai-flavor liquor wastewater as the inlet base, inoculating the pre-treated activated sludge into an SBR reactor, and operating using an SBR process; step S4, continuously operating the SBR reactor in step S3 for at least 30 days to obtain microalgae-bacteria granular sludge. This scheme can realize the rapid granulation of microalgae-bacteria granular sludge, and can efficiently degrade a variety of pollutants in brewing wastewater, solving the problems of slow granulation speed and low degradation efficiency for wastewater with high organic content and difficult to degrade in the existing microalgae-bacteria granular sludge granulation method.

Description

Technical Field

[0001] The present application relates to the field of sewage treatment, and in particular to a method for culturing microalgae-bacteria granular sludge based on Maotai-flavor liquor wastewater and its application. Background Art

[0002] A large amount of brewing wastewater is generated during the production of liquor. The quality and volume of brewing wastewater fluctuate greatly, with high chroma and turbidity. The mass concentration of suspended solids in unprecipitated mixed wastewater is as high as 3000-5000 mg·L -1 ;COD is generally between 15000 and 20000 mg·L -1 It contains a lot of nitrogen, phosphorus and other elements, of which the total nitrogen is about 50-500 mg·L -1 , total phosphorus is about 120~900 mg·L -1 If it is discharged directly without treatment, it will seriously harm the natural environment.

[0003] At present, the combined process of "pretreatment ~ anaerobic biological treatment ~ aerobic biological treatment ~ deep treatment" is generally used to treat brewing wastewater. In this process, the removal effect of pollutants in the aerobic biological treatment stage largely determines the removal efficiency and cost of Maotai-flavor liquor wastewater. Among them, aerobic biological treatment processes include activated sludge process (CAS), such as anoxic / aerobic process (AO), circulating activated sludge process (CASS), etc., or biofilm process, such as membrane bioreactor (MBR), biological contact oxidation process, etc. However, the CAS process has the disadvantages of high energy consumption and high treatment cost, and the membrane biological process is also severely restricted by high energy consumption, high cost and membrane pollution. Therefore, it is necessary to use new process technologies to degrade it.

[0004] As a new type of biological treatment technology, microalgae-bacteria granular sludge (MBGS) has shown many advantages in the field of wastewater treatment. It has high sedimentation and good adsorption capacity, can effectively absorb organic matter through the granulation of algae and bacteria, and can also use algae to produce oxygen to reduce energy consumption, while fixing more carbon in biomass to reduce greenhouse gas emissions. At present, MBGS has been widely studied for the treatment of urban sewage, domestic sewage and industrial wastewater, but MBGS always has the problems of slow granulation speed and low degradation efficiency for wastewater with high organic content and difficult to degrade. In view of this, there is an urgent need for an algae-bacteria granular sludge with a fast granulation speed and the ability to efficiently degrade brewing wastewater. Summary of the invention

[0005] In view of the above situation, the present application aims to provide a method for culturing microalgae-bacteria granular sludge based on Maotai-flavor liquor wastewater, so as to solve the current problems of slow granulation speed of algae-bacteria granular sludge, high degradation turbidity, and low efficiency in treating wastewater with high organic matter and toxic and difficult-to-degrade substances.

[0006] In order to achieve the above technical objectives, the first aspect of the present application provides a method for culturing microalgae-bacteria granular sludge based on Maotai-flavor liquor wastewater, comprising the following steps:

[0007] Step S1, taking activated sludge from a sewage treatment plant, aerating and sieving, to obtain pretreated activated sludge;

[0008] Step S2, preparing simulated Maotai-flavor liquor wastewater, the physicochemical parameters of the simulated Maotai-flavor liquor wastewater include: a mass concentration of chemical oxygen demand of 600-1000 mg / L, a mass concentration of phosphate ions of 2.5-7.5 mg / L, a mass concentration of total phosphorus of 3.4-8.0 mg / L, a mass concentration of ammonia nitrogen of 40-60 mg / L, a mass concentration of total nitrogen of 55-100 mg / L, and trace elements;

[0009] Step S3, using simulated Maotai-flavor liquor wastewater as the influent base, inoculating the pretreated activated sludge obtained in step S1 into the SBR reactor, and operating the reactor using the SBR process;

[0010] Step S4, continuously operating the SBR reactor in step S3 for at least 30 days to obtain microalgae-bacteria granular sludge.

[0011] Furthermore, in step S2, the method for configuring the chemical oxygen demand specifically includes the following steps: preparing simulated Maotai-flavor liquor wastewater by mixing acetate, glucose, and p-cresol, so that the mass concentration of chemical oxygen demand in the simulated Maotai-flavor liquor wastewater reaches 600-1000 mg / L; in the simulated Maotai-flavor liquor wastewater, the chemical oxygen demand provided by p-cresol accounts for 50±5% of the total chemical oxygen demand of the simulated Maotai-flavor liquor wastewater.

[0012] Furthermore, in step S3 and step S4, the operating parameters of the SBR reactor include: the carbon-nitrogen ratio of the simulated Maotai-flavor liquor wastewater is 6-10, the hydraulic retention time is 8-12 h, and the light intensity is 80-240 μmol m -2 s -1 , the aeration intensity is 1.0~2.5 cm / s.

[0013] Furthermore, in step S3 and step S4, the operating parameters of the SBR reactor include: the carbon-nitrogen ratio of the simulated Maotai-flavor liquor wastewater is 10±0.1; the hydraulic retention time is 8±0.1 h; the light intensity is 160±5 μmol m -2 s -1 ; Aeration intensity is 2.0±0.1 cm / s.

[0014] Furthermore, in step S3 and step S4, the SBR process includes the following five stages: water inlet, anaerobic treatment, aeration, sedimentation, and drainage, with a light-dark cycle of 12:12, and a volume exchange rate of 50±2% for each operation cycle.

[0015] Furthermore, the pH of the simulated Maotai-flavor liquor wastewater is 7.2-7.5.

[0016] Furthermore, in step S2, the dry weight of the inoculated pretreated activated sludge is 3.0±0.2 g / L.

[0017] The invention discloses an application of a method for culturing microalgae-bacteria granular sludge based on Maotai-flavor liquor wastewater, which is used to treat wastewater containing high organic matter and / or p-cresol.

[0018] The second aspect of the present application provides a method for preparing microalgae-bacteria granular sludge based on the method of culturing microalgae-bacteria granular sludge with Maotai-flavor liquor wastewater.

[0019] A third aspect of the present application provides an application of microalgae-bacteria granular sludge, which is an application of microalgae-bacteria granular sludge in treating wastewater containing high organic matter and / or p-cresol.

[0020] Furthermore, in the wastewater, the chemical oxygen demand provided by p-cresol accounts for 45-60% of the total chemical oxygen demand of the wastewater.

[0021] In summary, the present invention uses simulated Maotai-flavor liquor wastewater containing high concentration of organic matter and high concentration of p-cresol as the inlet matrix of the SBR reactor, and by optimizing the operating parameters of the reactor, can realize microalgae-bacteria granular sludge granulation in a short time; at the same time, the microalgae-bacteria granular sludge obtained by the above method can efficiently degrade a variety of high-concentration organic and inorganic pollutants in the simulated Maotai-flavor liquor wastewater, including p-cresol that is difficult to degrade and has certain toxicity; in addition, the above method can be used to carry out targeted screening and cultivation of microorganisms in the microalgae-bacteria granular sludge, and obtain a large number of dominant bacterial communities that can degrade p-cresol. Compared with the prior art, the present invention can realize the rapid cultivation of microalgae-bacteria granular sludge in wastewater containing high concentration of pollutants and toxic and difficult-to-degrade pollutants, and at the same time efficiently degrade a variety of organic pollutants in the water, so as to solve the current problems of slow granulation speed of algae-bacteria granular sludge, high degradation turbidity, and low efficiency in treating wastewater containing high organic matter and toxic and difficult-to-degrade substances. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0023] Figure 1 A schematic diagram of the morphological changes of the MBGS provided in Example 5 of the present invention;

[0024] Figure 2 A schematic diagram of the change of the sludge index of the MBGS provided in Example 5 of the present invention;

[0025] Figure 3 A schematic diagram showing the changes in the volatile suspended solid concentration and the suspended solid concentration of the MBGS provided in Example 5 of the present invention;

[0026] Figure 4 A schematic diagram of the change of PN / PS of MBGS provided in Example 5 of the present invention;

[0027] Figure 5 A schematic diagram showing the changes of LB-PN / PS of the MBGS provided in Example 5 of the present invention;

[0028] Figure 6 A schematic diagram of the change of TB-PN / PS of MBGS provided in Example 5 of the present invention;

[0029] Figure 7 A schematic diagram of the change of chlorophyll in the MBGS provided in Example 5 of the present invention;

[0030] Figure 8 This is the abundance diagram of prokaryotes at the phylum level of the MBGS provided in Example 5 of the present invention;

[0031] Fig. 9 This is the abundance diagram of prokaryotes at the family level of the MBGS provided in Example 5 of the present invention;

[0032] Fig.10 This is the abundance diagram of eukaryotic organisms at the phylum level of MBGS provided in Example 5 of the present invention;

[0033] Fig.11 The abundance heat map of eukaryotic organisms at the family and genus level of MBGS provided in Example 5 of the present invention;

[0034] Fig.12 The species gene abundance map at the secondary classification genus level of MBGS provided in Example 5 of the present invention;

[0035] Fig.13A schematic diagram showing the change in COD removal efficiency of MBGS provided in Example 5 of the present invention;

[0036] Fig.14 A schematic diagram showing the change in the removal efficiency of p-cresol by MBGS provided in Example 5 of the present invention;

[0037] Fig.15 A schematic diagram showing the change in ammonia nitrogen removal efficiency of MBGS provided in Example 5 of the present invention;

[0038] Fig.16 A schematic diagram showing changes in the removal efficiency of inorganic phosphorus by MBGS provided in Example 5 of the present invention;

[0039] Fig.17 Schematic diagram of the changes in turbidity removal caused by MBGS provided in Example 5 of the present invention. DETAILED DESCRIPTION

[0040] The technical solutions of the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the specification of the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection requested by the present application.

[0041] The sources of all raw materials in the present invention are not particularly limited and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0042] The present invention provides a method for culturing microalgae-bacteria granular sludge based on Maotai-flavor liquor wastewater, characterized in that it comprises the following steps:

[0043] Step S1, taking activated sludge from a sewage treatment plant, aerating and sieving, to obtain pretreated activated sludge;

[0044] Step S2, preparing simulated Maotai-flavor liquor wastewater, the physicochemical parameters of the simulated Maotai-flavor liquor wastewater include: a mass concentration of chemical oxygen demand of 600-1000 mg / L, a mass concentration of phosphate ions of 2.5-7.5 mg / L, a mass concentration of total phosphorus of 3.4-8.0 mg / L, a mass concentration of ammonia nitrogen of 40-60 mg / L, a mass concentration of total nitrogen of 55-100 mg / L, and trace elements;

[0045] Step S3, using simulated Maotai-flavor liquor wastewater as the influent base, inoculating the pretreated activated sludge obtained in step S1 into the SBR reactor, and operating the reactor using the SBR process;

[0046] Step S4, continuously operating the SBR reactor in step S3 for 90 days to obtain microalgae-bacteria granular sludge.

[0047] Specifically, in some embodiments, the activated sludge is pretreated to activate the metabolic activity of microorganisms in the sludge and improve the quality and performance of the sludge; at the same time, wastewater containing high concentrations of p-cresol and organic matter is used as influent, various parameters of the reactor operation stage are adjusted, and the microorganisms in the activated sludge are targetedly screened and domesticated from the initial stage of microalgae-bacteria granular sludge cultivation, ultimately obtaining microalgae-bacteria granular sludge that can be quickly granulated and can efficiently degrade complex wastewater.

[0048] In some embodiments, in step S2, the method for configuring chemical oxygen demand specifically includes the following steps: mixing acetate, glucose, and p-cresol to configure simulated Maotai-flavor liquor wastewater so that the mass concentration of chemical oxygen demand in the simulated Maotai-flavor liquor wastewater reaches 600-1000 mg / L; in the simulated Maotai-flavor liquor wastewater, the chemical oxygen demand provided by p-cresol accounts for 50±5% of the total chemical oxygen demand of the simulated Maotai-flavor liquor wastewater.

[0049] Specifically, in some embodiments, acetate, glucose, and p-cresol can simulate the organic matter present in wastewater and provide a carbon source for biomass; among them, p-cresol can also simulate the phenolic compounds produced in the liquor brewing process, inhibit the metabolic activity of microorganisms, and increase the difficulty of treating simulated wastewater.

[0050] In some embodiments, in step S3 and step S4, the operating parameters of the SBR reactor include: the carbon-nitrogen ratio of the simulated Maotai-flavor liquor wastewater is 6-10, the hydraulic retention time is 8-12 h, and the light intensity is 80-240 μmol m -2 s -1 , the aeration intensity is 1.0~2.5 cm / s.

[0051] Preferably, in some embodiments, the carbon-nitrogen ratio of the simulated Maotai-flavor liquor wastewater is 10±0.1; the hydraulic retention time is 8±0.1 h; the light intensity is 160±5 μmol m -2 s -1 ; Aeration intensity is 2.0±0.1 cm / s.

[0052] In some embodiments, in step S3 and step S4, the SBR process includes the following five stages: water inlet, anaerobic, aeration, sedimentation, and drainage, the light-dark cycle is 12:12, and the volume exchange rate of each operation cycle is 50±2%.

[0053] Specifically, it simulates the day and night alternation of the natural environment and regulates the growth and metabolism of microorganisms.

[0054] In some embodiments, the pH of the simulated Maotai-flavor liquor wastewater is 7.2-7.5.

[0055] Specifically, the appropriate pH helps maintain the enzyme activity and cell function of microorganisms and improves the efficiency of biological treatment. The simulated Maotai-flavor liquor wastewater with a pH of 7.2 to 7.5 is more conducive to improving biological activity and enhancing the treatment effect of microorganisms on wastewater.

[0056] In some embodiments, in step S2, the dry weight of the inoculated pretreated activated sludge is 3.0±0.1 g / L.

[0057] Specifically, inoculating a sufficient amount of activated sludge can ensure that there are a sufficient number of microorganisms in the reaction system to initiate and participate in the formation process of granular sludge, increasing the possibility of forming a stable granular structure.

[0058] Example 1

[0059] This embodiment provides a method for culturing microalgae-bacteria granular sludge based on Maotai-flavor liquor wastewater, characterized in that it includes the following steps:

[0060] Step S1, taking activated sludge from a sewage treatment plant, aerating and sieving, to obtain pretreated activated sludge;

[0061] Step S2, preparing simulated Maotai-flavor liquor wastewater according to Table 2, and adjusting the pH of the simulated Maotai-flavor liquor wastewater to 7.0-7.5;

[0062] Step S3, using simulated Maotai-flavor liquor wastewater as the influent base, and inoculating the pretreated activated sludge obtained in step S1 into four SBR reactors, so that the dry weight of the activated sludge in the reactor reaches 3 g / L; at the same time, the operation cycle of the SBR reactor is set to five stages: influent-anaerobic-aeration-sedimentation-drainage, the volume exchange ratio of each cycle is 50%, the light-dark cycle of the reactor environment is 12:12, and the temperature is 25±2°C;

[0063] Step S4, continuously operating the SBR reactor in step S3 for at least 30 days to obtain microalgae-bacteria granular sludge.

[0064] In step S3 of this embodiment, the specific operating parameters of the reactor are as follows:

[0065] The carbon-nitrogen ratio of the simulated Maotai-flavor liquor wastewater was 8; the light intensity was 160 μmol m -2 s -1 ; The hydraulic retention time is 8 h, and the aeration intensity of the four reactors R1 to R4 are: 0.5; 1.0; 2.0; 2.5 cm / s. The operation cycle of the SBR reactor is shown in Table 1; the formula of the simulated Maotai-flavor liquor wastewater is shown in Table 2.

[0066] Table 1. Reactor operating parameters

[0067]

[0068] Table 2. Formula for simulating Maotai-flavor liquor wastewater

[0069]

[0070] Example 2

[0071] The difference from Example 1 is that the operating parameters of the reactor are as follows:

[0072] The carbon-nitrogen ratio of the simulated Maotai-flavor liquor wastewater was 8; the hydraulic retention time was 8 h, the aeration intensity was 2.0 cm / s; and the light intensities of reactors R1 to R4 were 0; 80; 160; and 240 μmol m -2 s -1 .

[0073] Example 3

[0074] The difference from Example 1 is that the operating parameters of the reactor are as follows:

[0075] The hydraulic retention time was 8 h, the aeration intensity was 2.0 cm / s, and the light intensity was 160 μmol m -2 s -1 ; The carbon-nitrogen ratios of the simulated Maotai-flavor liquor wastewater in reactors R1~R4 are 4; 6; 8; 10 respectively.

[0076] In this embodiment, the carbon-nitrogen ratio is mainly regulated by adjusting the dosage of glucose, sodium acetate, p-cresol and ammonium chloride. The specific dosages are shown in Table 3:

[0077] Table 3

[0078]

[0079] Example 4

[0080] The difference from Example 1 is that the operating parameters of the reactor are as follows:

[0081] The aeration intensity was 2.0 and the light intensity was 160 μmol m -2 s -1 ; The carbon-nitrogen ratio of the simulated Maotai-flavor liquor wastewater is 10; the hydraulic retention times of reactors R1 to R4 are 4; 8; 12; 16 h, respectively.

[0082] In this embodiment, when the hydraulic retention time of reactors R1 to R4 is 4, 8, 12, and 16 h, the operating parameters of the reactors are shown in Table 4:

[0083] Table 4. Reactor operating parameters

[0084]

[0085] Example 5

[0086] The difference from Example 1 is that the operating parameters of the reactor are as follows:

[0087] The aeration intensity was 2.0 and the light intensity was 160 μmol m -2 s -1 ; The carbon-nitrogen ratio of the simulated Maotai-flavor liquor wastewater is 8; The hydraulic retention time of reactors R1 to R3 is 4; 8; 12 h respectively; The pH of the simulated Maotai-flavor liquor wastewater is 7.2 to 7.5. Among them, the operating parameters of the reactor are shown in Table 5.

[0088] Table 5. Running time of each stage of the pilot experiment

[0089]

[0090] Please refer to Tables 6 to 10 for the results of the above examples.

[0091] Table 6

[0092]

[0093] Note: Table 6 is a table showing the characteristics of algae-bacteria particles and wastewater removal performance at each stage of the experiment in Example 1.

[0094] According to the test results in Example 1, the SVI of the biomass in the reactor R1 (0.5 cm / s) on the 30th day of operation was 30It was 150.9 ± 0.28 mL / g, and the protein and polysaccharide contents were low, indicating that the viscosity between the biomass in this reactor was low and the sedimentation property was poor. Combining with the phenomenon of black and odorous water in the reactor, it further showed that it was difficult to form microalgae-bacterial granular sludge under this condition. At the same time, R2 (1.0 cm / s), R3 (2.0 cm / s), and R4 (2.5 cm / s) all formed microalgae-bacterial granular sludge within 60 days, indicating that when the aeration intensity of the reactor was 1.0 or 2.0 or 2.5 cm / s, it was helpful to form microalgae-bacterial granular sludge. At the same time, in the later stage of granulation (30 - 60 days), through the experimental detection data, it was found that the detection results of the biomass in the R2 - R4 reactors were as follows: the particle size ranking was R2 (1.0 cm / s) > R3 (2.0 cm / s) > R4 (2.5 cm / s); the sedimentation property ranking was R3 (2.0 cm / s) < R4 (2.5 cm / s) < R2 (1.0 cm / s); the chlorophyll a content ranking was R3 (2.0 cm / s) > R4 (2.5 cm / s) > R2 (1.0 cm / s), indicating that the algal-bacterial particle structure formed in R3 (2.0 cm / s) was denser and more complete. Based on the above detections, when the aeration intensity was 1.0 - 2.5 cm / s, microalgae-bacterial granular sludge could be formed, and when the aeration intensity was 2.0 cm / s, the performance of forming microalgae-bacterial granular sludge was the best.

[0095] Table 7

[0096]

[0097] Note: Table 7 is the table of the characteristics of algal-bacterial particles and the wastewater removal performance at each stage of the experiment in Example 2.

[0098] According to the detection results in Example 2, the particle size of the granular sludge formed by R1 (0 μmol m -2 s -1 ) was 0.38 ± 0.15 mm, but the presence of chlorophyll a was not detected, indicating that under the condition of no light, it was difficult for algae to grow and reproduce, and microalgae-bacterial granular sludge could not be prepared. At the same time, R2 (1.0 cm / s), R3 (2.0 cm / s), and R4 (2.5 cm / s) all formed microalgae-bacterial granular sludge within 60 days, indicating that when the light intensity of the reactor was 80, 160, 240 μmol m -2 s -1 , it was helpful to form microalgae-bacterial granular sludge. At the same time, through the experimental detection data, it was found that in the later stage of granulation, the detection results of the biomass in the R2 - R4 reactors were as follows: the particle size ranking was that the particle size was R3 (160 μmol m -2 s -1) > R2 (80 μmol m -2 s -1 ) > R4 (240 μmol m -2 s -1 ); The sedimentation strength ranking is R3 (160 μmol m -2 s -1 ) < R2 (80 μmolm -2 s -1 ) < R4 (240 μmol m -2 s -1 ), indicating that the microalgae-bacterial granular sludge structure formed in R3 (160 μmol m -2 s -1 ) is more stable and compact. Based on the above detections, when the light intensity is 80, 160, 240 μmol m -2 s -1 , microalgae-bacterial granular sludge can be formed, and when the aeration intensity is 160 μmol m -2 s -1 , the performance of the formed microalgae-bacterial granular sludge is better.

[0099] Table 8

[0100]

[0101] Note: Table 8 is the table of the characteristics of algal-bacterial particles and the wastewater removal performance at each stage of the experiment in Example 3.

[0102] According to the detection results in Example 3, the SVI of R1 (4) on the 30th day of operation 30 is 100.2 ± 0.03 mL / g. At this time, the sludge sedimentation is poor, and the protein and polysaccharide contents are low; at the same time, it is observed that the water quality in reactor R1 is blackened, and the biomass is flocculently distributed, and no microalgae-bacterial granular sludge is formed. R2 (6), R3 (8) and R4 (10) all form microalgae-bacterial granular sludge within 60 days, indicating that when the carbon-nitrogen ratio in the simulated sauce-flavor Baijiu wastewater is 6, 8, 10, it is helpful to form microalgae-bacterial granular sludge. At the same time, through the experimental detection data, it can be found that in the later stage of granulation, the detection results of the biomass in reactors R2-R4 are as follows: the particle size ranking is R3 (8) > R4 (10) > R2 (6); the sedimentation strength ranking is R4 (10) < R3 (8) < R2 (6), indicating that the microalgae-bacterial granular sludge structure formed in R4 (10) is more stable and compact. In summary, when the carbon-nitrogen ratio of the simulated sauce-flavor Baijiu wastewater is 6, 8, 10, microalgae-bacterial granular sludge can be formed, and when the carbon-nitrogen ratio of the simulated sauce-flavor Baijiu wastewater is 10, the performance of the formed microalgae-bacterial granular sludge is better.

[0103] Table 9

[0104]

[0105] Note: Table 9 shows the characteristics of algal-bacterial granules and the wastewater removal performance at each stage of the experiment in Example 4.

[0106] According to the test results in Example 4, the SVI values measured for reactors R1 (4 h) and R4 (16 h) at 30 days were 30 75.2 ± 0.03 mL / g and 80.2 ± 7.4 mL / g respectively. At the same time, the protein and polysaccharide contents of the biomass in the reactors were measured to be low, and microalgae-bacterial granular sludge could not be cultivated as expected. However, R2 (8 h) and R3 (12 h) completed the granulation of microalgae-bacterial granular sludge within 60 days; in the later stage of reactor operation, the biomass of R2 (8 h) was significantly higher than that of R3 (12 h), indicating that the gradually increasing volumetric loading at a smaller HRT enabled the microorganisms to have a higher growth rate; when the particle size ranking was R3 (12 h) > R2 (8 h) and the sedimentation performance ranking was R3 (12 h) < R2 (8 h), it showed that a shorter HRT could increase the hydraulic scouring intensity and selection pressure, making the particle structure more uniform and compact; at the same time, a shorter HRT could prompt the microorganisms to secrete more extracellular polymers (EPS), which was more conducive to enhancing the microbial activity and particle stability. Based on the above tests, it shows that when the hydraulic retention time is 8 h and 12 h, microalgae-bacterial granular sludge can be formed, and when the hydraulic retention time is 8 h, the performance of forming microalgae-bacterial granular sludge is better.

[0107] Table 10

[0108]

[0109] Note: Table 10 shows the data of the microbial community richness and diversity of the algal-bacterial granules on the 90th day in Example 5.

[0110] According to the test results in Example 5 and Figure 1 it can be known that within the initial 25 days, the biomass concentration in reactor R1 (4 h) showed a downward trend and maintained at 2.0 g / L starting from the 25th day; at this time, the SVI ratio of the algal-bacterial granular sludge was much less than 1 and the EPS content was low, indicating poor sedimentation performance of the biomass in reactor R1; at the same time, through microscopic observation, it was found that the sludge in reactor R1 was flocculent on the 25th day and the water body showed a black, smelly and putrid phenomenon, making it difficult to form microalgae-bacterial granular sludge. Therefore, reactor R1 was stopped from operating, but the operating time of R2 (8 h) and R3 (12 h) was adjusted to 90 days, and the best operating parameters for granulation under simulated sauce-flavored Baijiu wastewater were studied by analyzing the morphological changes, physicochemical properties and microbial community of particle formation.

[0111] Morphological changes and sedimentation performance of algae and fungi particles Figure 1 , 2, 3. The average particle sizes of algae and fungi particles in the R2 (8 h) and R3 (12 h) reactors after 90 days of operation were 1.445 mm and 1.827 mm, respectively. Figure 1 The results showed that granulation appeared on the 30th day in reactors R2 (8 h) and R3 (12 h), algae that could be observed with the naked eye appeared on the 70th day, and the growth of filamentous microorganisms was detected during the 90-day operation. Figure 3 As shown in Figure 2, the MLSS and MLVSS of R2 (8 h) decreased and then increased from 15 to 40 days. Among them, the MLSS content of the microalgae-bacteria granular sludge reached the lowest on the 30th day, and the SVI 30 / SV I5 At day 30, SVI 30 The average values ​​are all around 60 mg / L, indicating that the microalgae-bacteria granular sludge has good sedimentation properties and can maintain a stable state. In addition, the growth of chlorophyll a was detected from the 10th to the 30th day, indicating that algae have grown in the biomass in the reactor under the condition of light. The above test data show that microalgae-bacteria granular sludge has appeared on the 30th day of operation of the R2 (8 h) reactor, which is consistent with the gradual formation of particles observed under the microscope for about 30 days. At the same time, according to the microscope observation, large and mature microalgae-bacteria granular sludge was formed on the 50th day of operation of the reactor.

[0112] EPS plays a vital role in the particle formation, sedimentation and structural stability of microbial aggregates. In order to study the role of each EPS component in the particles, the concentration and material composition of EPS during the entire experimental period were analyzed, such as Figures 4 to 6 As shown. The trends of EPS content changes in R2 (8 h) and R3 (12 h) were basically the same during the entire operation, but the content of R2 (8 h) was slightly higher than that of R3 (12 h). In addition, the large amount of tightly bound exopolymers TB-EPS secreted by microorganisms in microalgae-bacteria granular sludge was mainly protein (PN), which was the main contributor to particle formation and biomass. This suggests that the successful granulation in simulated Maotai-flavor liquor wastewater may be partly attributed to the higher PN content, which can enhance the hydrophobicity of the cell surface, thereby reducing the Gibbs free energy and promoting microbial aggregation, thereby forming particles with stable structure and good sedimentation. However, on the 61st day, the LB-EPS of the microalgae-bacteria granular sludge detected increased, and the TB-EPS content was less. By the 81st day, the LB-EPS content decreased and the TB-EPS increased, which was also consistent with the increase in MLSS content, and there may be a phenomenon of particle lysis.

[0113] The richness and diversity of the microbial community in the reactor are shown in Table 10. The coverage index of the sample is above 0.999, indicating that the sample contains all species of microorganisms and the sequencing depth is sufficient. During the experiment, the abundance of the microbial community in R2 (8 h) and R3 (12 h) gradually increased during the granulation process, but it was always lower than the initial sludge state. The number of OTUs formed in the particles at D50 was low, indicating that the formation of granular sludge involves the selection of microorganisms with the highest adaptability, among which microorganisms with stronger adaptability continue to exist, while microorganisms with poorer adaptability are eliminated. However, with the operation of the reactor, the number of species and the Chao and Ace indicators increased, indicating that the particles are gradually adapting to the simulated sauce-flavor liquor wastewater. High-throughput sequencing of microbial communities showed that Figures 8 to 11 As shown in the figure, Proteobacteria, Bacteroidetes and Actinobacteria accounted for 35.5-51.9%, 5.6-44.6% and 1.7-28% respectively, which are dominant phyla and play a vital role in the formation of microalgae-bacteria granular sludge and the degradation of organic pollutants. In the heat map at the family and genus level, Comamnadaceae and Flavobacteriaceae accounted for 3.5-28.7% and 1.5-13.6% in R2 (8 h) and R3 (12 h), respectively, which play an important role in promoting EPS secretion and participating in the formation of algae-bacteria granules. The content of Rhodocyclaceae and Pesudomonas in R2 (8 h) was significantly greater than that in R3 (12 h), which played a dominant role in the degradation of benzene compounds. Analysis of eukaryotic microorganisms showed that at the phylum level, green algae (Chlorophyta) were the dominant species and played an important role in particle formation and stability.

[0114] In order to further reveal the different behaviors of the R2 (8 h) and R3 (12 h) experiments at the molecular level, the embodiments of the present invention also summarize the genes between the R2 (8 h) and R3 (12 h) samples through the classification of the Gene Ontology (GO) secondary level pairs, such as Fig.12As shown. According to GO annotation, it is divided into molecular function (CC), cellular component (MF) and biological process (BP). The gene functions of R2 (8 h) are slightly higher than those of R3 (12 h), and the difference in gene functions between the two is not obvious. By comparing the DEP sequence with the NR database and calculating the genus-level microbial community distribution based on the corresponding protein abundance, it can be obtained that Zoogloea and Sphaerotilus play a role in structural support, maintaining biological activity and cooperating with other bacterial communities in the formation of algae-bacteria granular sludge, and can also effectively remove organic pollutants, which is crucial to maintaining the stability and function of sludge; at the same time, when Zoogloea and Sphingomonas are significantly more in reactor R2 (8 h) than in R3 (12 h), it is more conducive to the improvement of particle stability and sedimentation.

[0115] In order to further detect the removal effect of the mature microalgae-bacteria granular sludge on the pollutants in the simulated Maotai-flavor liquor wastewater, the concentrations of COD, p-cresol, ammonia nitrogen and inorganic phosphorus in the reactor were monitored during the operation stage of Example 5. Figures 13 to 17 As shown. In the later stage of the operation of reactor R2, the removal rates of COD, p-cresol, ammonia nitrogen, and inorganic phosphorus in the artificial simulated Maotai-flavor liquor wastewater can reach 95%, 95%, 99%, and 86%, respectively. At this time, the effluent is clear and transparent, indicating that the formed mature microalgae-bacteria granular sludge can effectively remove organic and inorganic pollutants in the simulated Maotai-flavor liquor wastewater and reduce the turbidity of the wastewater. Even for the toxic and difficult-to-degrade p-cresol, it can achieve a good removal effect.

[0116] The above embodiment of the present invention analyzes the method of rapid granulation of microalgae-bacteria granular sludge in simulated Maotai-flavor liquor wastewater, and studies are conducted from the five factors of aeration intensity, carbon-nitrogen ratio, light conditions, hydraulic retention time and influent pH. The results show that when the aeration intensity is 2 cm / s and the light intensity is 160 μmol m -2 s -1, carbon-nitrogen ratio of 10, HRT of 8 h, pH of 7.2-7.5, the rapid granulation of microalgae-bacteria granular sludge can be achieved on the 30th day; the microalgae-bacteria granular sludge formed at the same time not only has a high biomass concentration and good sedimentation, but is also rich in tightly bound extracellular polymers TB-EPS mainly composed of protein (PN), which can further enhance the stability of the particle structure. The microalgae-bacteria granular sludge formed at this time can also effectively remove organic pollutants and difficult-to-degrade and toxic p-cresol in simulated Maotai-flavor liquor wastewater. In addition, in the above embodiments of the present invention, Zoogloea and Sphingomonas play an important role in the granulation and degradation of p-cresol. The present invention also provides a certain data reference for the rational cultivation of microalgae-bacteria granular sludge in Maotai-flavor liquor wastewater, and can also be used as a low-carbon, low-energy consumption, low-cost sewage treatment technology in the field of liquor wastewater treatment, and can also provide certain technical support for the subsequent research on the removal of organic matter from Maotai-flavor liquor wastewater.

[0117] The above are only preferred embodiments of the present application and are not intended to limit the present invention. Although the present application has been described in detail with reference to the examples, those skilled in the art can still modify the technical solutions recorded in the aforementioned examples or make equivalent substitutions for some of the technical features therein. However, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for culturing microalgae-bacteria granular sludge based on Maotai-flavor liquor wastewater, characterized in that: The following steps are involved: Step S1, taking activated sludge from a sewage treatment plant, aerating and sieving, to obtain pretreated activated sludge; Step S2, preparing simulated Maotai-flavor liquor wastewater, the physicochemical parameters of the simulated Maotai-flavor liquor wastewater include: a mass concentration of chemical oxygen demand of 600-1000 mg / L, a mass concentration of phosphate ions of 2.5-7.5 mg / L, a mass concentration of total phosphorus of 3.4-8.0 mg / L, a mass concentration of ammonia nitrogen of 40-60 mg / L, a mass concentration of total nitrogen of 55-100 mg / L, and trace elements; Step S3, using simulated Maotai-flavor liquor wastewater as the influent base, inoculating the pretreated activated sludge obtained in step S1 into the SBR reactor, and operating the reactor using the SBR process; Step S4, continuously operating the SBR reactor in step S3 for 30 days to obtain microalgae-bacteria granular sludge; In step S2, the method for preparing chemical oxygen demand specifically comprises the following steps: mixing acetate, glucose and p-cresol to prepare simulated Maotai-flavor liquor wastewater, so that the mass concentration of total chemical oxygen demand in the simulated Maotai-flavor liquor wastewater reaches 600-1000 mg / L; in the simulated Maotai-flavor liquor wastewater, the chemical oxygen demand provided by p-cresol accounts for 50±5% of the total chemical oxygen demand of the simulated Maotai-flavor liquor wastewater; In step S3 and step S4, the operating parameters of the SBR reactor include: the carbon-nitrogen ratio of the simulated Maotai-flavor liquor wastewater is 10; the hydraulic retention time is 8 h; the light intensity is 160 μmol m -2 s -1 ; The aeration intensity is 2.0 cm / s; the pH of the simulated Maotai-flavor liquor wastewater is 7.2-7.

5.

2. The method for culturing microalgae-bacteria granular sludge based on Maotai-flavor liquor wastewater according to claim 1, characterized in that: In step S3 and step S4, the SBR process includes the following five stages: water inlet, anaerobic, aeration, sedimentation, and drainage, with a light-dark cycle of 12:12 and a volume exchange rate of 50±2% for each operation cycle.

3. The method for culturing microalgae-bacteria granular sludge based on Maotai-flavor liquor wastewater according to claim 1, characterized in that: In the step S2, the dry weight of the inoculated pretreated activated sludge is 3.0±0.1 g / L.

4. A microalgae-bacteria granular sludge prepared according to the method for culturing microalgae-bacteria granular sludge based on Maotai-flavor liquor wastewater according to any one of claims 1 to 3.

5. An application of the microalgae-bacteria granular sludge according to claim 4, characterized in that: Application of microalgae-bacteria granular sludge in treating wastewater containing high organic matter and p-cresol.

6. The use of microalgae-bacteria granular sludge according to claim 5, characterized in that: In the wastewater, the chemical oxygen demand provided by p-cresol accounts for 45-60% of the total chemical oxygen demand of the wastewater.

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