Preparation method of algal-bacterial symbiotic filler and filler composite structure based on algal-bacterial symbiotic filler

Abstract

The invention discloses a preparation method of a bacteria-algae symbiotic filler, which specifically comprises the following steps: adding an activated sludge dispersion liquid into a reactor filled with a filler, operating for 7-10 days under an aeration condition, and introducing simulated tail water in the operation process; then chlorella is inoculated according to the volume ratio of the activated sludge dispersion liquid to the chlorella dispersion liquid being 1: (5-50), operation is conducted for 14-20 days at the temperature of 22-30 DEG C under illumination, and the light-dark ratio is that illumination is conducted for 6-12 h, and darkness is conducted for 12-18 h; tail water of the simulated sewage plant is introduced in the operation process; the filler hung with the algal-bacterial symbiotic biological membrane is obtained. In the formed algal-bacterial symbiotic membrane, the microalgae can promote enrichment of nitrogen and phosphorus removal flora and organic matter metabolism functional flora, and bacteria can improve the photosynthesis performance and carbon sequestration performance of the microalgae through material exchange, information transfer and other ways, so that the algal-bacterial symbiotic system can efficiently purify N / P / organic matter in a water body; meanwhile, the emission of greenhouse gas is reduced. The invention also discloses a filler composite structure based on the algal-bacterial symbiotic filler.

Description

Technical Field

[0001] The invention relates to a method for preparing a bacteria-algae symbiotic filler, and also relates to a filler combination structure based on the bacteria-algae symbiotic filler. Background Art

[0002] For the water pollution control industry, traditional treatment technologies have disadvantages such as high energy consumption, high cost, and greenhouse gas emissions (such as CO2, N2O, CH4) during water treatment. Microalgae has the potential to treat sewage and fix CO2. Microalgae use nitrogen, phosphorus and other substances in sewage and CO2 as raw materials, release O2 through photosynthesis, and promote aerobic degradation of pollutants, thereby achieving sewage treatment and CO2 fixation at the same time. However, a single microalgae system has poor sedimentation, is easily lost with tail water, is greatly affected by the external environment, and has weak risk resistance, which limits the application of microalgae. Summary of the invention

[0003] Purpose of the invention: The purpose of the present invention is to provide a method for preparing a bacteria-algae symbiotic filler, which generates a bacteria-algae biofilm on the filler. The bacteria-algae symbiotic system has good sedimentation and risk resistance, and can also improve the sewage treatment effect. Another purpose of the present invention is to provide a filler combination structure based on the above-mentioned bacteria-algae symbiotic filler, and apply the filler combination structure to a reactor to treat sewage.

[0004] Technical solution: The preparation method of the bacteria-algae symbiotic filler of the present invention is specifically as follows: adding an activated sludge dispersion into a reactor filled with filler, operating under aeration conditions for 7 to 10 days, and introducing simulated tail water during the operation; then inoculating Chlorella at a volume ratio of 1:5 to 50 between the activated sludge dispersion and the Chlorella dispersion, operating at 22 to 30°C and light for 14 to 20 days, wherein the light-dark ratio is: 6 to 12 hours of light and 12 to 18 hours of darkness; introducing simulated sewage plant tail water during the operation; the activated sludge and microalgae adhere to form a biofilm in the order of inoculation to obtain a filler with a bacteria-algae symbiotic biofilm.

[0005] The method of the present invention adopts a biofilm-forming method of first inoculating sludge to form a bacterial biofilm on the surface of the filler, and then inoculating microalgae to form a bacterial-algae symbiotic biofilm, that is, the microalgae will adhere to the first formed bacterial biofilm to form a microalgae biofilm (bacteria-algae symbiotic biofilm).

[0006] It takes 7 to 10 days for bacterial biofilm to form on the filler. The bacterial biofilm is formed first, and then algae are inoculated to form bacterial-algal biofilm. The total biofilm maturity time is 21 to 30 days.

[0007] Among them, the activated sludge is the activated sludge that has been domesticated and cultivated; the domestication and cultivation process of the activated sludge is as follows: the sludge used in this study was taken from the second sedimentation tank of a sewage treatment plant in Jiangning District, Nanjing City, Jiangsu Province. After the sludge was retrieved, it was first sieved through a sieve (1mm×1mm) to remove large particle impurities, and the supernatant was removed after gravity sedimentation for 24 hours, and then tap water was added to wash it 3 times and then it was left to stand for use. After the sludge was washed, the pH was controlled to be 7.5-8.5 and the water temperature was 25-30℃. The sludge was aerated for 24 hours (air aeration), and then the sludge concentration was diluted to MLSS of 100-500mg / L. The sludge dispersion and the Chlorella dispersion were 1:1 in volume ratio. The same initial concentration of Chlorella dispersion was passed into the simulated tail water for domestication, and the aeration was continued for 3-7 days to obtain the domesticated activated sludge. The domesticated activated sludge is more likely to adhere to the surface of the filler to form a bacterial biofilm, which is also conducive to the mutual adhesion and harmonious symbiosis of the bacterial biofilm and the subsequently inoculated microalgae cells. Directly inoculating undomesticated sludge into the reactor and then inoculating Chlorella can easily cause the death of a large number of Chlorella.

[0008] Among them, continuous aeration for 3 to 7 days maintains the dissolved oxygen (DO) concentration at 0.8 to 1.8 mg / L.

[0009] Wherein, the filler is a hollow cylindrical MBBR filler; the material of the filler is polyethylene.

[0010] The filling rate of the filler in the reactor is 30-50%.

[0011] The water inlet and outlet of the reactor are operated in a bottom-in and top-out mode.

[0012] Wherein, a water distribution orifice plate is provided at the water inlet of the reactor.

[0013] Among them, the formula of simulated tail water is: each liter of simulated tail water contains the following concentrations of substances: sodium acetate 64 mg / L, ammonium chloride 19.11 mg / L, potassium dihydrogen phosphate 2.20 mg / L, sodium nitrate 60.71 mg / L, magnesium sulfate 30 mg / L, calcium chloride 20 mg / L, EDTA (ethylenediaminetetraacetic acid) 1.0 mg / L and trace element solution 1 mL / L.

[0014] Among them, each liter of trace element solution contains substances with the following concentrations: boric acid 1.8 mg / L, ferric chloride 12 mg / L, copper sulfate 0.2 mg / L, manganese sulfate 1.2 mg / L, sodium molybdate 0.6 mg / L, zinc sulfate 1.5 mg / L, cobalt chloride 1.6 mg / L and potassium iodide 1.5 mg / L; the solvent for preparing the trace element solution is water.

[0015] The initial concentration of the activated sludge dispersion is 100-500 mg / L; the initial concentration of the Chlorella dispersion is 100-500 mg / L; and the initial concentrations of the two during inoculation are the same.

[0016] The filler combination structure based on the above-mentioned bacteria-algae symbiotic filler includes a plurality of porous spherical shells filled with bacteria-algae symbiotic fillers, and the plurality of porous spherical shells are connected in series in any combination through connecting rods or connecting lines.

[0017] Wherein, the filling rate of the biofilm filler in the porous spherical shell is 30% to 70%.

[0018] The size of the through holes on the porous spherical shell is smaller than the size of the biofilm filler; the mesh holes on the spherical shell are in the shape of a rectangle (8 to 16 mm in length and 16 mm in width). The material of the spherical shell is polypropylene.

[0019] The present invention forms a bacterial-algae biofilm by first inoculating sludge and then inoculating microalgae biofilm, improves the pollution reduction and carbon reduction ability of microalgae, prevents it from being lost with water, and uses filler assembly to prevent the filler from being lost with water and external water flow and pollutants from destroying the biofilm on the surface of the filler; then it is applied to ecological water bodies to improve treatment efficiency and reduce greenhouse gas emissions. The present invention promotes the adhesion and growth of microalgae on the surface of bacterial biofilm by pre-taming the bacterial community to form a symbiotic biofilm of bacteria and algae, thereby preventing the loss of microalgae with water and improving the risk resistance of the bacterial-algae symbiotic system. Among them, the bacterial community is used to improve the photosynthetic performance of microalgae and improve the photosynthetic carbon fixation ability of microalgae; while the microalgae assimilates and absorbs nutrients in the ecological water body, it performs photosynthesis and releases oxygen, which supplies nutrients such as organic matter to the bacterial community for decomposition and metabolism, and the microalgae promotes the enrichment of functional bacterial communities such as nitrogen and phosphorus, organic matter metabolism and EPS secretion, thereby improving the pollution reduction and carbon reduction ability of the overall filler system for the water body.

[0020] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0021] (1) In the bacteria-algae symbiotic membrane formed by the present invention, the microalgae can promote the enrichment of denitrification and phosphorus removal bacteria and organic matter metabolism functional bacteria, and the bacteria can improve the photosynthetic performance and carbon fixation performance of the microalgae through material exchange and information transmission, so that the bacteria-algae symbiotic system can efficiently purify N / P / organic matter in the water body and reduce greenhouse gas emissions.

[0022] (2) In the process of forming the bacteria-algae symbiotic film, the present invention adopts the method of first inoculating sludge and then inoculating microalgae to form a bacteria-algae biofilm, which can effectively overcome the disadvantage that microalgae are easily lost with water and improve the sedimentation and risk resistance of the bacteria-algae symbiotic system. At the same time, compared with the simultaneous bacteria-algae biofilm method, this biofilm method can further improve the pollution reduction and carbon reduction capabilities of the bacteria-algae symbiotic system.

[0023] (3) The fillers with symbiotic membranes of bacteria and algae are assembled to form a filler combination structure, which can further prevent the disadvantage of microalgae being easily lost in ecological water bodies, so that the fillers with symbiotic membranes of bacteria and algae can continue to exist in ecological water bodies and exert their pollution reduction and carbon reduction capabilities. At the same time, it can also prevent external water flow and pollutants from destroying the symbiotic membrane of bacteria and algae on the fillers in the spherical shell; finally, the microalgae release oxygen through photosynthesis, which helps to improve the self-purification ability of the water body. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of one of the combined structures of assembling bacteria-algae symbiotic fillers into a filler combination;

[0025] Figure 2 It is a schematic diagram of the structure of the reactor in the process of forming the bacteria-algae symbiotic filler;

[0026] Figure 3 This is a physical picture of a hollow cylindrical MBBR filler;

[0027] Figure 4 This is a physical picture of a spherical shell;

[0028] Figure 5 The carbon fixation performance of fillers obtained by different cultivation methods;

[0029] Figure 6 The removal effects of N, P and organic matter on fillers obtained by different cultivation methods;

[0030] Figure 7 A physical picture showing the application of the filler combination formed by the bacteria-algae symbiotic filler of Example 1 to a gallery-type bioreactor;

[0031] Figure 8 To compare the carbon fixation effect of fillers with different hydraulic retention times in gallery bioreactors;

[0032] Fig. 9 Comparison of COD removal effects at different hydraulic retention times in gallery bioreactors;

[0033] Fig.10 The comparison of ammonia nitrogen removal effect with different hydraulic retention time in gallery bioreactor;

[0034] Fig.11 The comparison of total nitrogen removal effect at different hydraulic retention times in gallery bioreactors;

[0035] Fig.12 The comparison of total phosphorus removal effect with different hydraulic retention time in gallery bioreactor;

[0036] Fig.13This is a schematic diagram of the filler combination structure used in the gallery bioreactor of Example 2. DETAILED DESCRIPTION

[0037] Figure 2 The continuous flow biofilm reactor of the present invention has a water inlet at the bottom of the reactor, a water distribution orifice plate at the water inlet, and a water outlet at the top of the reactor, so that the water inlet and water outlet of the reactor are operated in a bottom-in-top-out mode; a plurality of aeration stones are placed in the reactor, and the aeration stones are connected to an external air pump through an air pipe.

[0038] Example 1

[0039] The preparation method of the bacteria-algae symbiotic filler of the present invention is specifically as follows:

[0040] Will Figure 3 The hollow cylindrical MBBR filler (diameter 25 mm) shown is added to the continuous flow biofilm reactor, and the filling rate is 30% (v / v), that is, the filling volume of the filler is 30% of the reactor volume; an activated sludge dispersion with an initial concentration of 100 mg / L is added to the reactor, and it is operated for 10 days under aeration conditions. During the operation, simulated tail water is introduced; then the activated sludge dispersion and the Chlorella dispersion (the initial concentration of the Chlorella dispersion is 100 mg / L) are inoculated at a volume ratio of 1:50 Chlorella, control the temperature at 25-30℃, wrap the plant growth light strips around the reactor, set the timer to start lighting at 7:00 am every day and end the simulation at 7:00 pm, ensuring 12h (light): 12h (darkness); run for 18 days, and pass simulated tail water during the operation; obtain the filler with bacteria-algae symbiotic biofilm; to ensure that the filler in the reactor is in a suspended state, the reactor water inlet adopts the "bottom-in and top-out" operation mode, and the simulated tail water is sucked to the water inlet at the bottom of the reactor by a peristaltic pump.

[0041] After the biofilm in the reactor is mature and stable (the total maturation time is 28 days), the original operating conditions are maintained unchanged. The CO2 gas flux and the inlet and outlet water quality (COD, NH4 + -N, TN, TP), the test results are as follows Figures 5-6 shown.

[0042] Among them, in Example 1, the activated sludge is domesticated activated sludge, and the domestication and cultivation process of the activated sludge is as follows: the sludge used in this study was taken from the second sedimentation tank of a sewage treatment plant in Jiangning District, Nanjing City, Jiangsu Province. After the sludge was retrieved, it was first sieved through a sieve (1mm×1mm) to remove large particle impurities, and the supernatant was removed after gravity sedimentation for 24 hours, and then tap water was added to wash it 3 times and then it was left to stand for use. After the sludge was washed, the pH was controlled to be 7.5-8.5 and the water temperature was 25-30°C. The sludge was aerated for 24 hours (air aeration), and then the sludge concentration was diluted to MLSS of 100 mg / L, and the sludge dispersion and the Chlorella dispersion were 1:1 in volume ratio. The Chlorella dispersion with the same initial concentration was passed into the simulated tail water for domestication, and the aeration was continued for 3-7 days (the dissolved oxygen concentration in the simulated tail water during the aeration process was 0.8-1.5 mg / L), and the domesticated activated sludge was obtained.

[0043] Comparative Example 1

[0044] Comparative Example 1 uses the same continuous flow film forming reactor as in Example 1. Figure 3 The hollow cylindrical MBBR filler (diameter 25 mm) shown is added to a continuous flow biofilm reactor with a filling rate of 30% (v / v); only Chlorella is inoculated in the reactor, and a Chlorella dispersion with an initial concentration of 100 mg / L of the same volume as in Example 1 is added, the temperature is controlled at 25-30° C., a plant growth light strip is wrapped around the reactor, and a timer is set to start illumination at 7:00 am every day and end the simulation at 7:00 pm to ensure 12 h (illumination): 12 h (darkness); the reactor is operated for 28 days, and simulated tail water is introduced during the operation; Chlorella adheres to the surface of the filler to obtain a filler with a microalgae biofilm.

[0045] After the biofilm in the reactor is mature and stable (the total maturation time is 28 days), the original operating conditions are maintained unchanged. The CO2 gas flux and the inlet and outlet water quality (COD, NH4 + -N, TN, TP), the test results are as follows Figures 5-6 shown.

[0046] Comparative Example 2

[0047] Comparative Example 1 uses the same continuous flow film forming reactor as in Example 1. Figure 3The hollow cylindrical MBBR filler (25 mm in diameter) shown is added to the continuous flow biofilm reactor, with a filling rate of 30% (v / v); the bacterial solution and algae solution are inoculated into the reactor at the same time, that is, the activated sludge dispersion and the Chlorella dispersion are added to the reactor at a volume ratio of 1:50, and the initial inoculation concentration of the two is maintained at 100 mg / L; the added volume of each of the two is the same as in Example 1; the temperature is controlled at 25-30°C, the plant growth light strip is wrapped around the reactor, and the timer is set to start lighting at 7:00 am every day and end the simulation at 7:00 pm to ensure 12h (light): 12h (darkness); run for 28 days, and pass simulated tail water during the operation; the bacteria and microalgae inoculated synchronously adhere to the surface of the filler to obtain a filler with bacterial and algal biofilm. The activated sludge in Comparative Example 2 is also the activated sludge domesticated by the same method as in Example 1.

[0048] After the biofilm in the reactor is mature and stable (the total maturation time is 28 days), the original operating conditions are maintained unchanged. The CO2 gas flux and the inlet and outlet water quality (COD, NH4 + -N, TN, TP), the test results are as follows Figures 5-6 shown.

[0049] like Figure 5 As shown in Figure 1, the CO2 gas flux of the pure algae system in Comparative Example 1 is only -69.43 mg / m 2 / d, after the activated sludge was inoculated and mixed with biofilm, the CO2 fixation performance of the bacteria-algae synchronous system of comparative example 2 and the bacteria-first-then-algae system of example 1 were both enhanced, and the CO2 gas flux of the two increased to -108.32 mg / m 2 / d and -119.98mg / m 2 / d, CO2 fixation rate also increased from 20.04% to 31.50% and 35.30%. The results show that adding a small amount of activated sludge can promote the absorption of CO2 by Chlorella, and the biofilm method of bacteria first and then algae is more conducive to improving the CO2 fixation efficiency of the bacterial-algal symbiotic system. Different biofilm methods also have a significant effect on the purification efficiency of sewage plant tail water ( Figure 6 ). Compared with the pure algae system, the COD removal rates of the bacteria-algae synchronous system and the bacteria-first-then-algae system were increased from 51.57% to 56.54% and 62.33%, and the TP removal rates were increased from 74.92% to 78.79% and 84.23%, respectively. The effluent quality met the "Surface Water Environmental Quality Standard" (GB 3838-2002) Class IV (COD ≤ 30 mg / L, TP ≤ 0.3 mg / L). The bacteria-algae synchronous system and the bacteria-first-then-algae system had a significant effect on NH4 + -N and TN removal rates were significantly improved, and NH4 +The removal rate of -N increased from 50.14% to 83.66% and 89.44%, and the removal rate of TN increased from 43.09% to 64.97% and 66.93%, which shows that the biofilm formation method of first bacteria and then algae in the present invention can greatly improve the pollution reduction performance of the bacteria-algae symbiotic filler.

[0050] Wherein, the formula of the simulated tail water used in Example 1 and Comparative Examples 1 to 2 is (the water quality of the simulated tail water refers to the "Pollutant Discharge Standard for Urban Sewage Treatment Plants" (GB 18918-2002) Level A): per liter of simulated tail water, the following concentrations of substances are contained: sodium acetate 64mg / L, ammonium chloride 19.11mg / L, potassium dihydrogen phosphate 2.20mg / L, sodium nitrate 60.71mg / L, magnesium sulfate 30mg / L, calcium chloride 20mg / L, EDTA (ethylenediaminetetraacetic acid) 1.0mg / L and trace element solution 1mL / L. Wherein, per liter of trace element solution, the following concentrations of substances are contained: boric acid 1.8mg / L, ferric chloride 12mg / L, copper sulfate 0.2mg / L, manganese sulfate 1.2mg / L, sodium molybdate 0.6mg / L, zinc sulfate 1.5mg / L, cobalt chloride 1.6mg / L and potassium iodide 1.5mg / L; the solvent for preparing the trace element solution is water.

[0051] like Figure 1 As shown, the filler combination structure based on the bacteria-algae symbiotic filler of Example 1 includes a plurality of porous spherical shells filled with bacteria-algae symbiotic fillers, and the plurality of porous spherical shells are connected in series in any combination through connecting rods or connecting lines.

[0052] Example 2

[0053] like Fig.13 As shown, a filler combination structure is prepared based on the bacteria-algae symbiotic filler in Example 1, and the filler combination structure includes a plurality of porous spherical shells filled with bacteria-algae symbiotic fillers, and the plurality of porous spherical shells are connected in series by connecting rods, and the spacing between adjacent porous spherical shells is 40 mm; wherein the filling rate of biofilm fillers in the porous spherical shells is 50%.

[0054] The above-mentioned filler combination was added to the gallery-type bioreactor, and three parallel experiments were carried out. The hydraulic retention time (HRT) of the three gallery-type bacteria and algae bioreactors was set to 12h, 24h, and 48h, respectively, to investigate the pollution reduction and carbon reduction effects of the three reactors with different HRT.

[0055] The corridor reactor is made of plexiglass, 570 mm long, 240 mm wide and 140 mm high. Four corridors with a length of 460 mm, a width of 40 mm and a height of 80 mm are arranged in parallel in the middle. There is a 30 mm connecting area between two adjacent corridors for water to flow through.

[0056] The above filler combination is added to each corridor of the reactor to construct a corridor-type bacteria-algae bioreactor (such as Figure 7 The reactor is fed with water from the first gallery on the left and discharged from the first gallery on the right. The inlet and outlet pipes are 20 mm long and 10 mm in outer diameter. A water baffle 50 mm long and 30 mm from the bottom is set 30 mm away from the water inlet to reduce the scouring of the algae symbiotic filler by water flow. The CO2 gas emission flux is determined by static box-gas chromatography.

[0057] The fixation of CO2 in gallery-type algae bioreactors with different HRTs is shown in Figure 2. Figure 8 The CO2 fixation performance of the reactors with different HRTs increased with the increase of operation time, and the CO2 gas flux of emission reduction reached the maximum on the 20th day. On the 20th day, the CO2 gas flux of the gallery-type bacteria-algae bioreactor with an HRT of 12h was -121.27mg / m 2 / d, the CO2 gas flux in the reactor with HRT of 24h increased to -402.89mg / m 2 / d. The CO2 gas flux in the reactor with HRT of 48h is -267.23mg / m 2 / d. The results showed that the gallery-type bacteria-algae bioreactor with a HRT of 24h had the best CO2 fixation performance.

[0058] The removal efficiency of COD in gallery-type algae bioreactors with different HRTs is shown in Figure 2. Fig. 9 As shown. The COD removal efficiency of different HRT reactors increases with the increase of operation time, and the COD removal efficiency reaches the highest on the 20th day of operation, and the effluent meets the "Surface Water Environmental Quality Standard" (GB 3838-2002) Class IV (COD ≤ 30 mg / L). However, there are significant differences in the COD removal efficiency of gallery-type algae bioreactors with different HRT. For example, on the 20th day, the COD removal rate of the reactor with an HRT of 12h was only 61.82%, and the effluent COD was 21.65mg / L; the COD removal rate in the reactor with an HRT of 24h was further increased to 68.85%, and the effluent COD was 17.67mg / L, which met the "Surface Water Environmental Quality Standard" (GB 3838-2002) Class III (COD ≤ 20mg / L).

[0059] Fig.10 The results of the gallery-type algae bioreactor with different HRTs on NH4 + The gallery-type algae bioreactors with different HRTs operated efficiently and stably during the test period. The gallery-type algae bioreactor with HRT of 12h NH4 + -N removal rate is 49.58% to 59.49%, HRT is 24h and 48h reactor NH4 +-N removal rate was stable at 96.71% to 99.38%. Compared with the reactor with HRT of 12h, the NH4 + The -N removal effect is significantly improved, meeting the "Surface Water Environmental Quality Standard" (GB 3838-2002) Class II (NH4+-N≤0.5mg / L).

[0060] The removal efficiency of TN by gallery-type algae bioreactors with different HRTs is shown in Figure 2. Fig.11 As shown. The TN removal efficiency in the gallery-type bacteria-algae bioreactors with different HRTs increased with the increase of operating time, and the TN removal efficiency reached the highest on the 20th day of operation. However, there were significant differences in the TN removal efficiency of the gallery-type bacteria-algae bioreactors with different HRTs. For example, on the 20th day, the TN removal rate of the reactor with an HRT of 12h was only 33.80%, and the TN in the effluent was 9.06mg / L; in the reactors with HRTs of 24h and 48h, the TN removal rates increased to 48.58% and 48.51%, respectively.

[0061] The removal efficiency of TP in gallery-type algae bioreactors with different HRTs is shown in Figure 2. Fig.12 As shown. The TP removal efficiency in the gallery-type bacteria-algae bioreactors with different HRTs increased with the increase of operation time, and reached the highest TP removal efficiency on the 20th day of operation, and the effluent met the Class III (TP≤0.2mg / L) of the Environmental Quality Standard for Surface Water (GB 3838-2002). There were significant differences in the TP removal efficiency in the gallery-type bacteria-algae bioreactors with different HRTs. Specifically, on the 20th day, the TP removal rate of the gallery-type bacteria-algae bioreactor with an HRT of 12h was 92.00%, and the effluent TP was 0.05mg / L. In the reactors with HRTs of 24h and 48h, the TP removal rates increased to 98.21% and 99.83%, respectively, and the effluent TP was 0.011mg / L and 0.002mg / L, respectively, meeting the Class II (TP≤0.1mg / L) of the Environmental Quality Standard for Surface Water (GB 3838-2002).

[0062] The corridor-type bacteria-algae bioreactor treats ecological water, and has good effects on the removal of N, P, organic matter and greenhouse gas emissions. The simulated wastewater formula used in Example 2 is the same as that in Example 1. The present invention aims to solve the problem that a single microalgae system has weak pollution reduction and carbon reduction capabilities. The bacteria and microalgae are combined. On the one hand, the bacteria-algae cells metabolize and secrete EPS, which is used to adhere and aggregate the bacteria-algae cells together to form a bacteria-algae biofilm, thereby improving the sedimentation and risk resistance of the bacteria-algae symbiotic system; on the other hand, the bacteria-algae symbiotic system formed can greatly improve the sewage treatment capacity when treating the tail water of the sewage treatment plant, and further improve the photosynthesis capacity and carbon fixation capacity of the microalgae.

Claims

1. A method for preparing a bacteria-algae symbiotic filler, characterized in that: Specifically, activated sludge dispersion is added to a reactor filled with fillers, and the reactor is operated under aeration conditions for 7 to 10 days, during which simulated tail water is introduced; then Chlorella is inoculated according to a volume ratio of activated sludge dispersion to Chlorella dispersion of 1:5 to 50, and the reactor is operated at 22 to 30°C and light for 14 to 20 days, wherein the light-dark ratio is: light for 6 to 12 hours and darkness for 12 to 18 hours; during the operation, simulated sewage plant tail water is introduced; and fillers with bacteria-algae symbiotic biofilms are obtained.

2. The method for preparing the bacteria-algae symbiotic filler according to claim 1, characterized in that: The activated sludge is activated sludge that has been domesticated and cultured; the domestication and culture process of the activated sludge is as follows: the cleaned sludge is aerated for 24 hours under the conditions of pH 7.5-8.5 and water temperature 25-30°C, the sludge concentration is diluted to MLSS 100-500 mg / L, the activated sludge dispersion and the Chlorella dispersion are inoculated with the same initial concentration of Chlorella dispersion at a volume ratio of 1:1, simulated tail water is introduced for domestication, and aeration is continued for 3-7 days to obtain the domesticated activated sludge.

3. The method for preparing the bacteria-algae symbiotic filler according to claim 2, characterized in that: Continue aeration for 3 to 7 days to maintain the dissolved oxygen concentration at 0.8 to 1.8 mg / L.

4. The method for preparing the bacteria-algae symbiotic filler according to claim 1, characterized in that: The filler is a hollow cylindrical MBBR filler.

5. The method for preparing the bacteria-algae symbiotic filler according to claim 1, characterized in that: The filling rate of the filler in the reactor is 30 to 50%.

6. The method for preparing the bacteria-algae symbiotic filler according to claim 1, characterized in that: The water inlet and outlet of the reactor are operated in a bottom-in-top-out mode.

7. The method for preparing the bacteria-algae symbiotic filler according to claim 6, characterized in that: A water distribution orifice plate is provided at the water inlet of the reactor.

8. The method for preparing the bacteria-algae symbiotic filler according to claim 1, characterized in that: The initial concentration of the activated sludge dispersion is 100-500 mg / L; the initial concentration of the Chlorella dispersion is 100-500 mg / L; the initial concentrations of the two when inoculated are the same.

9. The filler combination structure based on the bacteria-algae symbiotic filler according to claim 1 is characterized in that: It comprises a plurality of porous spherical shells with bacteria-algae symbiotic fillers inside, and the plurality of porous spherical shells are connected in series in any combination through connecting rods or connecting lines.

10. The packing combination structure according to claim 9, characterized in that: The filling rate of the biofilm filler in the porous spherical shell is 30% to 70%.

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