Preparation method and application of phycomycete compound

Abstract

The invention relates to the technical field of water treatment, in particular to a preparation method and application of a phycomycete compound. The phycomycete compound is applied to nitrogen and phosphorus removal and surface water treatment. Wherein the chlorella vulgaris and the quadruplex obliquus have strong reproductive capacity and strong adaptive capacity to environment, and absorb various elements such as carbon, nitrogen and phosphorus from water through autotrophy, heterotrophy and polyculture growth; activated sludge containing bacteroides and pseudomonas can degrade complex organic compounds, has metabolic capabilities such as heterotrophic denitrification and the like, and is beneficial to forming a co-culture system with microalgae in the initial culture stage; and nitrifying and denitrifying bacteria are compounded to consolidate the nitrogen removal environment order, so that the water body is effectively purified and the water color is good. The phycomycete compound obtained by the invention not only can be suitable for high-nitrogen simulation wastewater of a laboratory, but also can be applied to in-situ treatment of an actual river channel, has remarkable environmental benefits and has a wide application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, and in particular to a preparation method and application of an algae-bacteria complex. Background Art

[0002] The research and development of related technologies for nitrogen and phosphorus removal from waste / sewage has always been a hot topic in the field of water treatment. Traditional biological nitrogen and phosphorus removal technologies often have the problem of insufficient efficiency, and therefore they rely on physical or chemical methods to achieve the goal of water purification.

[0003] The removal of nitrogen and phosphorus from natural surface water bodies is of great significance in dealing with eutrophication of water bodies and protecting human health. The mixing of rainwater and sewage or the direct discharge of sewage causes sewage in the pipe network to enter the surface water body from the river outlet, so the problem of river water pollution is still occurring. Biotechnology for surface water pollution control is extremely rare. Most inventions rely on a specific device, equipment, reactor or carrier.

[0004] The bacteria-algae symbiotic technology will become a green and low-cost alternative technology for biological denitrification and phosphorus removal, and will be widely used in the treatment of simulated industrial wastewater, domestic wastewater, agricultural wastewater, and food processing wastewater. A previously disclosed bacteria-algae mixture (publication number CN107354110A) was applied to aquaculture tail water, but the removal effect on COD and TP was not shown. Another invention (publication number CN115491312A) focuses on the formation of Chlorella biofilm. Not only is the algae species single, but it only discloses the removal effect of TN in laboratory simulated sewage. There are also public inventions of complexes of polyalgae and polybacteria, but the polybacteria therein are usually artificially compounded exogenous strains, and their stability and diversity are far inferior to those of indigenous strains in activated sludge, and they do not pay attention to the denitrification and phosphorus removal effects on natural surface water bodies.

[0005] Therefore, how to correctly and reasonably use bacteria and algae technology to remove nitrogen and phosphorus, especially in the field of surface water treatment, is an urgent problem that needs to be solved. Summary of the invention

[0006] In order to solve the above problems, the present invention provides a method and application of an algae-bacteria complex in denitrification and phosphorus removal and surface water treatment. The method of the present invention can construct an efficient denitrification and phosphorus removal system using microalgae and activated sludge, and can also compound different populations and different proportions of exogenous bacteria to form a variety of algae-bacteria complexes to construct a more efficient system.

[0007] Furthermore, the present invention also provides the application of the algae-bacteria complex in various water treatments, which can fully utilize the advantages of multiple microalgae and multiple bacteria to purify water quality and significantly reduce total nitrogen, total phosphorus, COD Cr and ammonia nitrogen, significantly improving the effluent quality standards.

[0008] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0009] The present invention provides an algae-bacteria complex, which includes mixed microalgae and activated sludge or mixed microalgae, activated sludge and composite bacteria with denitrification function. The mixed microalgae include Chlorella vulgaris and Tetradesmus obliquus, the activated sludge includes at least bacterial flora of the phylum Bacteroidetes and the phylum Pseudomonas, and the composite bacteria with denitrification function include Nitrobacter, Nitrospira, Nitrosomonas, Pseudomonas and Bacillus.

[0010] The Chlorella vulgaris and Tetraselmis obliquus contained in the algae-fungus complex of the present invention have strong reproductive ability and environmental adaptability, can absorb various elements such as carbon, nitrogen, phosphorus, etc. from water, can grow autotrophically under CO2 and light conditions, fix CO2 and assimilate nitrogen and phosphorus; can grow heterotrophically under organic carbon conditions, use organic carbon as the only carbon source, and use nitrogen and phosphorus as essential elements for nucleic acids, cell membranes and energy storage, which are simultaneously fixed into the carbon skeleton; and can also grow efficiently in a mixed culture under the condition of coexistence of inorganic carbon and organic carbon.

[0011] The algae-bacteria complex of the present invention contains bacterial communities of the Bacteroidetes and Pseudomonas phyla. The microorganisms of the Bacteroidetes phylum can produce various lytic enzymes to degrade complex organic carbon compounds. Denitrifying bacteria are also present in the phylum, which have heterotrophic denitrification metabolic capabilities. Some bacterial communities in the Pseudomonas phylum have been identified as plant growth-promoting bacteria, which can synthesize auxins to enhance the interaction between algae and bacteria, and are conducive to forming a co-culture system with algae in the early stage of cultivation.

[0012] The algae-bacteria complex of the present invention contains Nitrobacter, Nitrospira, Nitrosomonas, Pseudomonas and Bacillus, which can enhance the denitrification effect. Bacteria of the genera Nitrobacter, Nitrospira and Nitrosomonas can be called nitrifying bacteria; bacteria of the genera Pseudomonas and Bacillus can be called denitrifying bacteria; they can be used for environmental sewage treatment research, can degrade pollutants, can remove nitrogen, and can be used for natural surface water environment restoration.

[0013] The present invention provides a method for preparing an algae-fungus complex, comprising the following steps:

[0014] Step 1) Cultivating a single species / mixed algae liquid: Chlorella vulgaris and Tetrasegmentosum obliquus algae species are respectively inoculated into BG11 liquid culture medium at a volume ratio of 2-4%, and cultured in a constant temperature and light incubator, with a light duration of 10-14 hours, a temperature controlled at 20-30° C., and cultured for 5-10 days to obtain Chlorella vulgaris liquid or Tetrasegmentosum obliquus liquid, and mixed to obtain a mixed microalgae liquid;

[0015] Step 2) Cultivating activated sludge: placing sludge with microbial activity in an SBR reactor for pre-cultivation, using 200-400 mg / L methanol as the only carbon source, ammonium chloride and potassium dihydrogen phosphate as nitrogen and phosphorus sources, controlling the C:N:P ratio to be approximately 100:5:1, and preparing activated sludge when the MLSS and SVI of the sludge in the reactor are relatively stable;

[0016] Step 3) preparing the algae-bacteria complex: inoculating the mixed microalgae liquid into the activated sludge to obtain the algae-bacteria complex, and then continuing to culture to meet the application conditions;

[0017] or,

[0018] Step 1) and step 2) are the same as above;

[0019] Step 3) Expanding and culturing the denitrification functional bacterial solution: adding the denitrification functional bacterial solution of claim 4 to the corresponding liquid culture medium at a volume ratio of 2-8%, and expanding and culturing for 4-6 days, controlling the culture temperature at 25-35° C., and the rotation speed at 100-200 r / min, to obtain the corresponding expanded bacterial solution;

[0020] Step 4) preparing the algae-bacteria complex: inoculating a mixed microalgae solution and a denitrification functional bacteria solution into the activated sludge to obtain the algae-bacteria complex, and then continuing to culture to meet the application conditions.

[0021] Preferably, when the activated sludge is used, the MLSS is 1200-1500 mg / L and the SVI is 50-100 mL / g.

[0022] Preferably, the algae density of the mixed microalgae liquid is 2×10 6 ~1×10 7 cell / mL, the cell number ratio of Chlorella vulgaris and Tetraselmis obliquus is (1-4):(1-4).

[0023] Preferably, the bacterial content of the denitrification functional bacterial solution is 2×10 7 ~2×10 8 cfu / mL, and the number ratios of the genera Nitrobacter, Nitrospira, Nitrosomonas, Pseudomonas and Bacillus are (1-2):(1-2):(1-2):(1-2):(1-2).

[0024] Preferably, the continuous culture conditions are: light intensity of 8000-12000 Lux, light-dark alternating cycle time of 3-6 h, water temperature of 25-30° C., dissolved oxygen of 2.0-4.0 mg / L, and culture time of 1-3 days.

[0025] The present invention also provides the use of the algae-bacteria complex in the in-situ treatment of laboratory high-nitrogen simulated wastewater, actual river water and river channels.

[0026] In summary, the method and application of an algae-bacteria complex in nitrogen removal, phosphorus removal and river management provided by the present invention have the following beneficial effects:

[0027] The present invention utilizes Chlorella vulgaris and Tetrasegmentella obliquus to form a mixed microalgae system, and prepares an algae-bacteria complex with activated sludge containing Bacteroidetes and Pseudomonas flora. The algae-bacteria complex can be directly inoculated into various bioreactors. Compared with a pure microalgae system and a pure activated sludge system, the system is more stable and has superiority in biomass growth and pollutant removal effects. Nearly 100% nitrogen and phosphorus removal effects can be achieved under laboratory conditions. After the demonstration device treats actual surface water bodies, the water body is improved by at least one standard.

[0028] The present invention adds bacterial flora of the genera Nitrobacter, Nitrospira, Nitrosomonas, Pseudomonas and Bacillus to the above-mentioned bacteria-algae complex to prepare another algae-bacteria complex. The preparation method is simple and the application mode is convenient. It is more suitable for high-nitrogen waste / sewage treatment and actual in-situ treatment of surface water bodies, can achieve water quality purification and ecological restoration, and has good social and environmental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the preparation steps of a specific embodiment of the present invention. DETAILED DESCRIPTION

[0030] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0031] Unless otherwise specified, the materials described in the present invention are all purchased by those skilled in the art.

[0032] The present invention provides an algae-bacteria complex, which includes mixed microalgae and activated sludge or mixed microalgae, activated sludge and composite bacteria with denitrification function. The mixed microalgae include Chlorella vulgaris and Tetraselena obliquus, the activated sludge includes at least bacterial flora of the phylum Bacteroidetes and the phylum Pseudomonas, and the composite bacteria with denitrification function include Nitrobacter, Nitrospira, Nitrosomonas, Pseudomonas and Bacillus.

[0033] The present invention has no special requirements for the source of microalgae species, and the preferred source is the freshwater algae species library of the Chinese Academy of Sciences. The present invention has no special requirements for the source of activated sludge, as long as it contains bacterial flora of Bacteroidetes and Pseudomonas. The preferred source is Shanghai Jiading Wastewater Treatment Plant A 2 The present invention has no special requirements on the source of the composite bacteria with denitrification function, and the preferred source is the China Industrial Microbial Culture Collection Management Center.

[0034] The present invention provides a method for preparing an algae-fungus complex, comprising the following steps:

[0035] Step 1) Cultivating a single species / mixed algae liquid: Chlorella vulgaris and Tetrasegmentosum obliquus algae species are respectively inoculated into BG11 liquid culture medium at a volume ratio of 2-4%, and cultured in a constant temperature and light incubator, with a light duration of 10-14 hours, a temperature controlled at 20-30° C., and cultured for 5-10 days to obtain Chlorella vulgaris liquid or Tetrasegmentosum obliquus liquid, and mixed to obtain a mixed microalgae liquid;

[0036] Step 2) Cultivating activated sludge: placing sludge with microbial activity in an SBR reactor for pre-cultivation, using 200-400 mg / L methanol as the only carbon source, ammonium chloride and potassium dihydrogen phosphate as nitrogen and phosphorus sources, controlling the C:N:P ratio to be approximately 100:5:1, and preparing activated sludge when the MLSS and SVI of the sludge in the reactor are relatively stable;

[0037] Step 3) preparing the algae-bacteria complex: inoculating the mixed microalgae liquid into the activated sludge to obtain the algae-bacteria complex, and then continuing to culture to meet the application conditions;

[0038] or,

[0039] Step 1) and step 2) are the same as above;

[0040] Step 3) Expanding and culturing the denitrification functional bacterial solution: adding the denitrification functional bacterial solution of claim 4 to the corresponding liquid culture medium at a volume ratio of 2-8%, and expanding and culturing for 4-6 days, controlling the culture temperature at 25-35° C., and the rotation speed at 100-200 r / min, to obtain the corresponding expanded bacterial solution;

[0041] Step 4) preparing the algae-bacteria complex: inoculating a mixed microalgae solution and a denitrification functional bacteria solution into the activated sludge to obtain the algae-bacteria complex, and then continuing to culture to meet the application conditions.

[0042] The microalgae liquid culture medium of the present invention is preferably BG11 liquid culture medium; the inoculation volume ratio of the algae seed liquid to the BG11 liquid culture medium is preferably 2-4%, more preferably 3%; the illumination time for culturing a single species / mixed algae liquid is preferably 10-14h, more preferably 12h, the temperature is preferably 20-30°C, more preferably 26°C, and the culture time is preferably 5-10 days, more preferably 7 days.

[0043] The preferred pre-culture conditions of the SBR reactor of the present invention are air aeration for 12 hours, daily water change and addition of methanol, ammonium chloride and potassium dihydrogen phosphate; the methanol addition amount is preferably 200-400 mg / L, more preferably 300 mg / L, and the preferred addition amounts of ammonium chloride and potassium dihydrogen phosphate are determined by C:N:P=100:5:1.

[0044] In the present invention, before preparing an algae-bacteria complex, the MLSS and SVI of the activated sludge in the SBR reactor must be relatively stable, preferably MLSS = 3000-4000 mg / L, SVI = 50-100 mL / g; the preferred MLSS of the activated sludge when used is 1200-1500 mg / L, which can ensure the sludge activity, the sludge concentration is appropriate, oxygenation will not be hindered, and the biological phase is rich and the sedimentation performance is good.

[0045] The bacteria with denitrification function described in the present invention are preferably Nitrobacter, Nitrospira, Nitrosomonas, Pseudomonas and Bacillus; the strain is freeze-dried bacterial powder, and the resurrection operation is preferably to use a sterile pipette to absorb 0.4-0.5mL of basic liquid culture medium into the freeze-drying tube to completely dissolve the freeze-dried bacterial powder, and the dissolved bacterial suspension is transferred to a test tube containing 4-5mL of basic liquid culture medium, mixed, and statically cultured; the static culture time is preferably 4-6 days, more preferably 6 days, to obtain the corresponding first-generation bacterial liquid; the basic liquid culture medium, Nitrobacter, Nitrospira and Nitrosomonas are preferably prepared K1 culture medium, Pseudomonas is preferably prepared LB culture medium, Bacillus is preferably prepared nutrient broth culture medium, more preferably using the corresponding finished culture medium, the present invention has no special limitation on the purchase channel of the finished culture medium, and the conventional purchase channel of technicians in this field can be used.

[0046] After the first generation of bacterial culture, the strain of the present invention preferably also includes expanding the culture of denitrification functional bacterial liquid. In the present invention, the expansion culture transfer conditions are preferably 2-8% by volume of the first generation bacterial liquid to the corresponding basic liquid culture medium, more preferably 5%; the expansion culture days are preferably 4-6 days, more preferably 4 days; the expansion culture temperature is preferably 25-35°C, more preferably 30°C; the culture speed is preferably 100-200r / min, more preferably 150r / min.

[0047] In the present invention, the algae density of the mixed microalgae liquid in the algae-bacteria complex is preferably 2×10 6 ~1×10 7 cell / mL, more preferably 6×10 6 cell / mL; the cell number ratio of the common Chlorella and the oblique Tetraselmus is preferably (1-4): (1-4), more preferably 1:1; the bacterial content of the denitrification functional bacterial solution is preferably 2×10 7 ~2×10 8 cfu / mL, more preferably 1×10 8 cfu / mL; the number ratio of the genus Nitrobacter, Nitrospira, Nitrosomonas, Pseudomonas and Bacillus is preferably (1-2):(1-2):(1-2):(1-2):(1-2), and more preferably 1:1:1:1:1. The present invention requires that the algae-bacteria complex be cultured for a period of time to stabilize the algae-bacteria complex system to meet the application conditions. The continuous culture conditions are preferably: light intensity 8000-12000 Lux, light-dark alternating cycle time 3-6 h, water temperature 25-30 ° C, dissolved oxygen 2.0-4.0 mg / L, and culture time 1-3 days; the light intensity is more preferably 10000 Lux, the light-dark alternating cycle time is more preferably 3 h, the water temperature is more preferably 26 ° C, the dissolved oxygen is more preferably 2.5 mg / L, and the culture time is more preferably 3 days before application.

[0048] The present invention also provides the use of the algae-bacteria complex in the in-situ treatment of laboratory high-nitrogen simulated wastewater, actual river water and river channels.

[0049] The application process of the present invention can be carried out in different seasons and under different weather conditions; the application process can be carried out under natural light. In the case of insufficient light, it is preferred to use an artificial light source, and more preferably, natural light combined with artificial light to supplement the light to 8000-12000Lux, so as to save electricity consumption costs and achieve the best water treatment effect.

[0050] In order to further illustrate the present invention, the method and application of an algae-fungus complex provided by the present invention in nitrogen removal and phosphorus removal and surface water treatment are described in detail below in combination with some embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0051] Example 1

[0052] A method for preparing an algae-bacteria complex comprises the following steps:

[0053] (1) Cultivating Chlorella vulgaris and Tetrasegmentosum obliquus algae liquid to prepare mixed microalgae liquid: 8 mL of the mother liquid of Chlorella vulgaris and Tetrasegmentosum obliquus in the stable period were inoculated into 250 mL of conventional BG11 liquid culture medium, and cultured in a constant temperature and light incubator. The culture temperature was set to 26°C, the light intensity was set to 6000 Lux, and the light was on from 9 am to 9 pm, and the rest of the time was dark. The culture was carried out for 7 days to obtain Chlorella vulgaris liquid and Tetrasegmentosum obliquus liquid. The algae cell density was measured, which was about 2×10 7 cell / mL, the two were mixed in a 1:1 ratio to obtain a mixed microalgae solution, and the culture was continued under the original conditions;

[0054] (2) Cultivating activated sludge: 3 L of sludge with microbial activity was placed in a 10 L SBR reactor for pre-cultivation, and 300 mg / L methanol was added as a carbon source, 57 mg / L ammonium chloride was added as a nitrogen source, and 13 mg / L potassium dihydrogen phosphate was added as a phosphorus source. Air aeration was performed from 9 am to 9 pm daily, and the dissolved oxygen was controlled to be greater than 2 mg / L. The water was changed at 8 am and nutrients were added at the above concentrations. The MLSS and SVI of the sludge in the reactor were observed. When the sludge concentration was too high, too low, or the sludge expanded, timely responses were taken, such as sludge discharge, addition of new sludge, addition of flocculants, etc., to achieve the purpose of relatively stable MLSS and SVI of the sludge in the reactor, that is, activated sludge was obtained.

[0055] (3) Preparation of algae-bacteria complex: Take the activated sludge of required concentration, MLSS = 1300 mg / L, SVI = 85 mL / g, and inoculate 6×10 6 The algae-bacteria complex was prepared from the mixed microalgae liquid prepared in 1% cell / mL (1). The subsequent culture conditions were set as follows: light intensity of 10000 Lux. Considering the light-shielding property of the sludge, the light intensity was increased. The light was illuminated for 3 hours and the dark was dark for 3 hours for 4 cycles per day to prevent the water temperature from rising due to excessive light exposure. The water temperature was controlled to be about 26°C and the dissolved oxygen was about 2.5 mg / L. Wastewater / sewage could be added after 2 days of culture.

[0056] Example 2

[0057] A method for preparing an algae-bacteria complex similar to that of Example 1, wherein the algae-bacteria complex has a stronger denitrification ability, comprises the following steps:

[0058] (1) Cultivating Chlorella vulgaris and Tetrasegmentosum obliquus algae liquid to prepare mixed microalgae liquid: 8 mL of the mother liquid of Chlorella vulgaris and Tetrasegmentosum obliquus in the stable period were inoculated into 250 mL of conventional BG11 liquid culture medium, and cultured in a constant temperature and light incubator. The culture temperature was set to 26°C, the light intensity was set to 6000 Lux, and the light was on from 9 am to 9 pm, and the rest of the time was dark. The culture was carried out for 7 days to obtain Chlorella vulgaris liquid and Tetrasegmentosum obliquus liquid. The algae cell density was measured, which was about 2×10 7 cell / mL, the two were mixed in a 1:1 ratio to obtain a mixed microalgae solution, and the culture was continued under the original conditions;

[0059] (2) Cultivating activated sludge: 3 L of sludge with microbial activity was placed in a 10 L SBR reactor for pre-cultivation, and 300 mg / L methanol was added as a carbon source, 57 mg / L ammonium chloride was added as a nitrogen source, and 13 mg / L potassium dihydrogen phosphate was added as a phosphorus source. Air aeration was performed from 9 am to 9 pm daily, and the dissolved oxygen was controlled to be greater than 2 mg / L. The water was changed at 8 am and nutrients were added at the above concentrations. The MLSS and SVI of the sludge in the reactor were observed. When the sludge concentration was too high, too low, or the sludge expanded, timely responses were taken, such as sludge discharge, addition of new sludge, addition of flocculants, etc., to achieve the purpose of relatively stable MLSS and SVI of the sludge in the reactor, that is, activated sludge was obtained.

[0060] (3) Expanding the culture of denitrification functional bacterial liquid: Dissolve the purchased freeze-dried strains of Nitrobacter, Nitrospira, Nitrosomonas, Pseudomonas and Bacillus with 0.5 mL of conventional liquid culture medium, transfer the dissolved bacterial suspension to a test tube containing 5 mL of basal liquid culture medium, mix well, and culture for 6 days to obtain the corresponding first-generation bacterial liquid; for the conventional liquid culture medium, Nitrobacter, Nitrospira and Nitrosomonas are purchased from K1 medium products, Pseudomonas are purchased from LB medium products, and Bacillus is purchased from nutrient broth medium products; 5 mL of the first-generation bacterial liquid is added to 100 mL of the corresponding conventional liquid culture medium for 4 days of second-generation expansion culture, the temperature is controlled at 30° C., and the rotation speed is 150 r / min to obtain the corresponding expanded bacterial liquid;

[0061] (4) Preparation of algae-bacteria complex: Take the activated sludge of required concentration, MLSS = 1400 mg / L, SVI = 90 mL / g, and inoculate 6 × 10 6 The mixed microalgae solution prepared in (1) was inoculated with the expanded bacterial solution prepared in (3), and the total bacterial solution concentration was 1×10 8 cfu / mL, and the concentrations of Nitrobacter, Nitrospira, Nitrosomonas, Pseudomonas, and Bacillus were 2×10 7cfu / mL, the algae-bacteria complex was obtained, and the subsequent culture conditions were set as: light intensity 10000Lux. Considering the light-shielding property of the sludge, the light intensity was increased, and the light was cycled for 3 hours and dark for 3 hours per day for 4 times to prevent the water temperature from rising due to excessive light exposure. The water temperature was controlled at about 26°C and the dissolved oxygen was about 2.5mg / L. Waste / sewage could be added after 3 days of culture.

[0062] Example 3

[0063] A similar algae-bacteria complex as described in Example 1 was used in a wastewater / sewage reactor for 2 days of culture for water treatment. The difference from Example 1 was that the initial MLSS of the algae-bacteria complex used was 1322.13 mg / L, the SVI was 65 mL / g, and the density of the mixed microalgae was 5.24×10 6 cell / mL. The water to be treated was actual surface water collected from a polluted river. The wastewater reactor used a conventional column photobioreactor with an effective volume of 2L and a treatment time of 7 days. During this period, MLSS fluctuated between 1322.13 and 1360.87 mg / L, and SVI 30 It fluctuates between 55 and 90 mL / g, and the dissolved oxygen is controlled at about 3 mg / L. The experimental water quality index data results are shown in Table 1:

[0064] Table 1 Changes in water quality indicators

[0065]

[0066]

[0067] As shown in Table 1, the river water initially collected was seriously polluted and belonged to Class V water according to the Surface Water Environmental Quality Standard (GB3838-2002). During the treatment, the sludge state was stable, the density of microalgae increased, and the algae-bacteria complex showed excellent water treatment effect. In summary, after one week of treatment with the algae-bacteria complex, the effluent COD, TN, NH3-N and TP decreased by 86.11%, 91.19%, 96.38% and 93.88% respectively, and the effluent water quality was improved to Class II water, with significant water treatment effect.

[0068] Example 4

[0069] The algae-bacteria complex used in Example 3 was applied to a demonstration project device, and the implementation location was the Third Industrial Park of Jiangsu Xinchen Environmental Protection Group. The water to be treated was actual surface water collected from the polluted river. The waste / sewage reactor was a new type of photobioreactor built in the park, with an effective volume of 150L and a treatment time of 15 days. The experimental water quality index data and calculation results are shown in Table 2:

[0070] Table 2 Changes in water quality of inlet and outlet water of the demonstration device

[0071] COD(mg / L) TN(mg / L) <![CDATA[NH3-N(mg / L)]]> TP(mg / L) DO(mg / L) Water Intake 19 1.59 0.61 0.58 4.36 Classification Ⅲ Ⅴ Ⅲ Ⅴ Ⅳ Water 7 0.75 0.13 0.19 12.35 Classification Ⅰ Ⅲ Ⅰ Ⅲ Ⅰ

[0072] As can be seen from the records in Table 2, according to the surface water environmental quality standard (GB3838-2002), the influent is seriously polluted and belongs to Class V water. After 15 days of treatment with the algae-bacteria complex of the present invention, the water quality is improved to Class III water, which fully meets the water quality requirements of the natural surface water body in the park. The effluent COD, NH3-N and DO even reach the Class I water standard, which is enough to show the superiority of the algae-bacteria complex in water treatment effect. The reduction of NH3-N is greater than that of TN. It is speculated that the nitrogen source that microalgae like to use is ammonia nitrogen. The substantial increase in DO also comes from the contribution of microalgae photosynthesis to produce oxygen. In addition to Chlorella vulgaris and Tetraselmis obliquus, the algae species in the water body after the experiment also appeared in Nostoc and Scalycanthus. It is speculated that the algae spores in the activated sludge reproduced under light conditions, enriching the diversity of mixed microalgae in the algae-bacteria complex, so the effluent water quality is difficult to achieve by the traditional activated sludge method.

[0073] Example 5

[0074] The algae-bacteria complex prepared in Example 2 was applied to a waste / sewage reactor and cultured for 3 days before water treatment. The water to be treated was simulated domestic sewage, but the nitrogen source was appropriately increased to explore the treatment effect of the algae-bacteria complex on high-nitrogen sewage. The waste / sewage reactor used a conventional flat-plate photobioreactor with an effective volume of 10L and a treatment time of 3 days. The changes in the inlet and outlet water quality are shown in Table 3:

[0075] Table 3 Treatment effect of laboratory simulated high nitrogen wastewater

[0076] Water Intake Water Degradation rate COD(mg / L) 500 39 92.20％ TN(mg / L) 60 1.49 97.52％ TP(mg / L) 6 0.99 83.50％

[0077] As shown in Table 3, the algae-bacteria complex has a good treatment effect on laboratory simulated high-nitrogen sewage. The removal rate of TN is as high as 97.52%. Compared with the traditional activated sludge treatment technology, the COD required to remove more than 58 mg / L of total nitrogen is more than 500 mg / L, which shows the advantages of the present invention in the field of water treatment; the removal effect of TP is not as good as that of TN. It is speculated that the algae-bacteria complex adds a bacterial community with denitrification function to enhance the removal effect of TN. At this time, the dominant effect of polyphosphate bacteria is not obvious enough, so that the polyphosphate bacteria lack sufficient carbon source to synthesize polyphosphates and PHB particles and other substances, thereby affecting the removal of phosphates. However, despite this, the effluent quality of TP can still meet the first-level emission standard of pollutants for urban sewage treatment plants.

[0078] Example 6

[0079] The algae-bacteria complex prepared in Example 2 was applied to the in-situ treatment of actual natural surface water bodies. The implementation location was an actual river in the industrial park at No. 207 Yuandong Avenue, Gaocheng Town, Yixing City, Wuxi City, Jiangsu Province. 2L of the algae-bacteria complex prepared in Example 2 was connected to the existing bioreactor in the river. The algae-bacteria complex can grow as a biofilm in the reactor and diffuse to the surrounding water body. The water treatment time was 20 days, and the sampling point was 1m away from the bioreactor. The changes in water quality indicators are shown in Table 4:

[0080] Table 4 Changes in water quality during in-situ treatment of surface water bodies

[0081] Days (d) 0 10 20 COD(mg / L) 15.34 13.28 12.00 TN(mg / L) 2.12 1.87 0.97 <![CDATA[NH3-N(mg / L)]]> 1.32 1.15 0.55 TP(mg / L) 0.27 0.21 0.17

[0082] As shown in Table 4, the algae-bacteria complex prepared by the present invention is also effective in the treatment of actual surface water bodies. When a small amount of algae-bacteria complex is added, the water quality of the surrounding waters outside the bioreactor is also improved in the case of continuous discharge of pollutants in the river. On the 20th day, the COD concentration value reached the Class I standard in the Surface Water Environmental Quality Standard (GB3838-2002), and the other recorded indicators were close to the Class II standard.

[0083] It can be seen from the records of the above embodiments that the preparation method of an algae-bacteria complex of the present invention is simple, and the core lies in the synergistic effect of microalgae and activated sludge, but the microalgae commonly used in the field of water treatment are preferred to ensure their contribution to denitrification and phosphorus removal, and the activated sludge is also preferred to contain Bacteroidetes and Pseudomonas. The bacterial flora of the Bacteroidetes can degrade complex organic compounds, and some of them also have heterotrophic denitrification metabolism ability. Some of the bacterial flora in the Pseudomonas are conducive to forming a symbiotic effect with microalgae in the early stage of cultivation, and jointly treat waste / sewage. The algae-bacteria complex of the present invention can also be added with exogenous bacterial agents, such as the denitrification functional bacteria, and it can also be considered to add phosphorus removal bacteria to enhance the denitrification, phosphorus removal and carbon reduction functions. In addition, the implementation method of the present invention is convenient, and the waste / sewage reactor can be selected according to actual needs. Whether it is a column type, a flat plate type or a new type of device, it is applicable and suitable for a variety of influent water quality. The application scope of the algae-bacteria complex is no longer limited to the laboratory. It has shown the ability to improve water quality in demonstration devices and actual surface water treatment, and has a broad market environment and application prospects.

[0084] Although the present invention has been disclosed in preferred embodiments and the above embodiments have been described in detail, it should not be understood as limiting the present invention. Under the concept of the present invention, the technical features in different embodiments can be combined, but any combination, omission, modification, etc. of the content within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing an algae-fungus complex, characterized in that: The following steps are involved: Step 1) Cultivating a single / mixed microalgae liquid: Inoculate a plurality of algae species into a BG11 liquid culture medium at a volume ratio of 2-4%, and culture in a constant temperature and light incubator, with a light duration of 10-14 hours and a temperature controlled at 20-30° C. for 5-10 days to obtain a single microalgae liquid, and mix to obtain a mixed microalgae liquid; Step 2) Cultivating activated sludge: placing sludge with microbial activity in an SBR reactor for pre-cultivation, using 200-400 mg / L methanol as the only carbon source, ammonium chloride and potassium dihydrogen phosphate as nitrogen and phosphorus sources, controlling the C:N:P ratio to be approximately 100:5:1, and preparing activated sludge when the MLSS and SVI of the sludge in the reactor are relatively stable; Step 3) preparing the algae-bacteria complex: inoculating the mixed microalgae liquid into the activated sludge to obtain the algae-bacteria complex, and then continuing to culture to meet the application conditions.

2. The method for preparing the algae-fungus complex according to claim 1, characterized in that: The step 3) of preparing the algae-bacteria complex is replaced by the following steps: Step 3') expanding the culture of the denitrification functional bacterial solution: adding 2-8% of the denitrification functional bacterial solution to the corresponding liquid culture medium for expansion culture for 4-6 days, controlling the culture temperature at 25-35° C. and the rotation speed at 100-200 r / min to obtain the corresponding expanded bacterial solution; Step 4') preparing the algae-bacteria complex: inoculating a mixed microalgae solution and a denitrification functional bacteria solution into the activated sludge to obtain the algae-bacteria complex, and then continuing to culture to meet the application conditions.

3. The method for preparing the algae-fungus complex according to claim 1 or 2, characterized in that: The algae species include Chlorella vulgaris and Tetraselena obliquus.

4. The method for preparing the algae-fungus complex according to claim 1 or 2, characterized in that: The algae density of the mixed microalgae liquid is 2×10 6 ~1×10 7 cell / mL, the cell number ratio of Chlorella vulgaris and Tetraselmis obliquus is (1-4):(1-4).

5. The method for preparing the algae-fungus complex according to claim 1 or 2, characterized in that: The sludge with microbial activity at least includes bacterial flora of the phylum Bacteroidetes and the phylum Pseudomonas.

6. The method for preparing the algae-fungus complex according to claim 1 or 2, characterized in that: In the step 2), when activated sludge is used, the MLSS is 1200-1500 mg / L and the SVI is 50-100 mL / g.

7. The method for preparing the algae-fungus complex according to claim 2, characterized in that: The bacteria having denitrification function include Nitrobacter, Nitrospira, Nitrosomonas, Pseudomonas and Bacillus.

8. The algae-fungus complex according to claim 2, characterized in that: The expanded bacterial solution contains 2×10 7 ~2×10 8 cfu / mL, the number ratio of the Nitrobacter, Nitrospira, Nitrosomonas, Pseudomonas and Bacillus is (1-2): (1-2): (1-2):(1-2):(1-2)。 9. The algae-fungus complex according to claim 1 or 2, characterized in that: The continuous culture conditions are as follows: light intensity of 8000-12000 Lux, light-dark alternating cycle time of 3-6 hours, water temperature of 25-30° C., dissolved oxygen of 2.0-4.0 mg / L, and culture for 1-3 days.

10. An application of an algae-bacteria complex, prepared by the preparation method according to any one of claims 1 to 9, characterized in that: The algae-bacteria complex was applied to treat laboratory high-nitrogen simulated wastewater.

11. An application of an algae-bacteria complex, prepared by the preparation method according to any one of claims 1 to 9, characterized in that: The algae-bacteria complex is applied to actual in-situ river management.

Images