Method for storing and reactivating bacteria-algae granular sludge

Abstract

The invention belongs to the technical field of sewage treatment, and discloses a bacteria-algae granular sludge storage and reactivation method which comprises the following steps: cleaning bacteria-algae granular sludge to be stored with pure water to obtain cleaned bacteria-algae granular sludge; adding the pretreated clear water and the cleaned bacteria-algae granular sludge into a storage reactor, and storing in a preset low-temperature environment and in a periodic light-dark alternating environment; when the stored bacteria-algae granular sludge needs to be reactivated, removing supernate in the storage reactor, and providing aeration and illumination in situ to obtain reactivated bacteria-algae granular sludge; a collaborative preservation system is formed through a clear water storage medium and coupling with a low-temperature environment and light-dark alternation period regulation and control means, so that the stored bacteria-algae system can quickly recover the sewage treatment efficiency, and meanwhile, the algae biomass is completely maintained; the obvious advantages are shown in the aspects of stability maintenance and function recovery efficiency of a symbiotic system of the bacteria-algae granular sludge.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, and specifically relates to a method for storing and reactivating bacterial and algal granular sludge. Background Technology

[0002] Microalgae granular sludge refers to a bio-aggregate formed by the symbiosis of microalgae and aerobic granular sludge. Its core lies in the integration of synergistic metabolism and structural function between bacteria and microalgae. Microalgae continuously supply dissolved oxygen to the symbiotic bacteria through photosynthesis, driving the efficient degradation of organic pollutants, while fixing carbon dioxide and absorbing nitrogen and phosphorus nutrients. Meanwhile, the carbon dioxide produced by bacterial metabolism provides substrates for microalgae growth. Based on the synergistic mechanism of bacteria and microalgae, it has shown significant potential in the simultaneous removal of nitrogen and phosphorus and carbon emission reduction in wastewater treatment, and is regarded as one of the cutting-edge technologies for achieving energy self-sufficiency and carbon neutrality in wastewater treatment plants. However, in the actual engineering application of microalgae granular sludge, it faces limitations such as loss of activity and irreversible structural damage during long-term storage.

[0003] Currently, traditional sludge storage technologies (such as low-temperature refrigeration, freeze drying, and chemical fixation) are mostly developed based on single microbial systems (such as pure bacterial aerobic / anaerobic granular sludge). Their design logic is difficult to adapt to the complex biological characteristics of the bacterial-algae symbiotic system in bacterial-algae granular sludge, thus failing to achieve the active preservation of bacterial-algae granular sludge across seasons or regions.

[0004] Specifically, long-term dark storage leads to the degradation of chloroplast function in microalgae and the loss of photosynthetic oxygen supply capacity, which in turn causes an imbalance in the bacterial community structure under the anoxic environment inside the aerobic granular sludge. While freeze-drying can extend the storage time, the dehydration process may cause particle disintegration and disordered spatial distribution of functional bacteria. The more fundamental contradiction lies in the fact that the functional stability of the bacterial-algae symbiotic system is highly dependent on the dynamic balance of bacterial-algae metabolic feedback and the integrity of the particle structure. Traditional storage methods often result in a mismatch between bacterial and algal metabolic rates due to the lack of design for coordinated regulation of light, temperature, and oxygen. For example, the photosynthetic chain of algae is interrupted in dark storage, and the inability to continuously supply oxygen forces aerobic bacteria to turn to endogenous respiration and release intracellular polymers, weakening the strength of the particle structure. The above problems are further amplified in extreme environments (such as high-altitude and high-salinity areas). Therefore, it is urgent to develop a new bacterial-algae granular sludge storage technology, which is a key breakthrough to promote the technology from the laboratory to engineering applications. Summary of the Invention

[0005] To address the technical problems existing in the prior art, the present invention provides a method for storing and reactivating granular sludge containing bacteria and algae, thereby solving the technical problem that traditional sludge storage technologies cannot achieve the active preservation of granular sludge containing bacteria and algae across seasons or regions.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a method for storing and reactivating granular sludge containing bacteria and algae, comprising: The stored bacterial and algae granular sludge was washed with pure water to obtain the washed bacterial and algae granular sludge. Pretreated clean water and washed algae granular sludge are added to the storage reactor and stored in a preset low-temperature environment with periodic light and dark alternation. When it is necessary to reactivate the stored bacterial and algal granular sludge, the supernatant in the storage reactor is removed, and aeration and light are provided in situ to obtain reactivated bacterial and algal granular sludge.

[0007] Furthermore, the bacterial and algae granular sludge to be stored is mature bacterial and algae symbiotic granular sludge; The preparation process of mature algae-microbe symbiotic granular sludge includes: Activated sludge is placed in an SBR reactor, using simulated wastewater as influent. The SBR reactor is run periodically until algae-bacterial symbiotic granular sludge is formed. Then, it is transferred to a cylindrical glass reactor for continuous operation to obtain mature algae-bacterial symbiotic granular sludge.

[0008] Furthermore, the concentration of COD in the simulated wastewater was 500-550 mg / L, and the concentration of NH4+ was... + The concentration of -N was 40-45 mg / L, TP was 6-8 mg / L, and Ca... 2+ The concentration is 80-100 mg / L.

[0009] Furthermore, when the SBR reactor is operated periodically, the operating time for each operating cycle is 5-6 hours; Within each operating cycle, the anaerobic operation time is 1-1.5 hours, and the aeration operation time is 3 hours 50 minutes to 4 hours 5 minutes. During the aeration operation, an environment with a light intensity of 4000-4500 lux is provided simultaneously, and the aeration rate is 1-2 L / min.

[0010] Furthermore, the pretreatment process for preparing clean water includes: Nitrogen gas is introduced into tap water to remove residual chlorine and oxygen, resulting in pretreated clean water; the nitrogen gas is introduced for 20-30 minutes.

[0011] Furthermore, the preset low temperature environment is 4±0.5℃.

[0012] Furthermore, in a periodic light-dark alternation environment, the light-dark time ratio in each light-dark alternation cycle is 1:1, and the light intensity is 3000-4500 lux.

[0013] Furthermore, in the periodic light-dark alternation environment, the light time in each light-dark alternation cycle is 6 hours and the dark time is 6 hours.

[0014] Furthermore, when it is necessary to reactivate the stored bacterial and algal granular sludge, the supernatant in the storage reactor is removed, and in-situ aeration and light treatment are provided to obtain reactivated bacterial and algal granular sludge, as follows: Remove the supernatant from the storage reactor; then, use the restored simulated wastewater as influent, and run the storage reactor under in-situ aeration of 1-2 L / min and light of 3000-4500 lux to obtain reactivated bacterial and algal granular sludge.

[0015] Furthermore, the concentration of COD in the simulated wastewater was restored to 500-520 mg / L, and the concentration of NH4+ was... + The concentration of -N was 35-40 mg / L, TP was 6-7 mg / L, and Ca... 2+ The concentration is 80-100 mg / L.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a method for storing and reactivating granular sludge containing bacteria and algae. The method utilizes pure water to wash the sludge before storage, thoroughly removing residual nutrients and metabolic byproducts, thereby eliminating unnecessary metabolic activity during storage and inducing the microorganisms in the sludge to enter a dormant state. Furthermore, using purified water as the storage medium, coupled with a low-temperature environment and a periodic light-dark cycle control mechanism, a synergistic preservation system is formed. This allows the bacteria-algae system to quickly restore its wastewater treatment efficiency after storage while maintaining complete algal biomass. Setting the storage temperature to a preset low-temperature environment effectively reduces the metabolic rate of microorganisms, ensuring the activity of the granular sludge. Applying a periodic light-dark cycle matches the survival needs of the algae in the granular sludge, maintaining its physiological activity and functional stability. This invention fills a technological gap in dedicated storage methods for granular sludge containing bacteria and algae, demonstrating significant advantages over conventional microbial preservation methods in maintaining the stability of the symbiotic system and improving functional recovery efficiency. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 These are photographs of the storage reactors used in Example 1 and the comparative example; Figure 2 This is a photograph of the bacterial and algal granular sludge before storage in Example 1; Figure 3 The image shows a photograph of the stored bacterial and algal granular sludge from Example 1. Figure 4 This is a graph showing the effect of bacterial and algal granular sludge in the in-situ recovery period in Example 1 on COD removal. Figure 5 To remove NH4 from the granular sludge of bacteria and algae in the in-situ recovery period in Example 1. + The effect curve of -N; Figure 6 This is a graph showing the change in chlorophyll content before and after storage of the bacterial and algal granular sludge in Example 1. Figure 7 The above is a photograph of the actual bacterial and algal granular sludge stored in the comparative example. Figure 8 A graph showing the COD removal effect of bacterial and algal granular sludge in the in-situ recovery period in the comparative example. Figure 9 To remove NH4 from granular sludge of bacteria and algae in the in-situ recovery period in the comparative example. + The effect curve of -N; Figure 10 This is a graph showing the change in chlorophyll content before and after storage of the bacterial and algal granular sludge in the comparative example. Detailed Implementation

[0019] To make the technical problems, technical solutions, and beneficial effects solved by this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] This invention provides a method for storing and reactivating granular sludge containing bacteria and algae, comprising the following steps: Step 1: Obtain the bacterial-algae granular sludge to be stored; wherein, the bacterial-algae granular sludge to be stored is mature bacterial-algae symbiotic granular sludge; specifically, the preparation process of mature bacterial-algae symbiotic granular sludge includes: Activated sludge was placed in an SBR reactor using simulated wastewater as influent. The SBR reactor was run periodically until algae-bacterial symbiotic granular sludge was formed. Afterward, it was transferred to a cylindrical glass reactor for continuous operation to obtain mature algae-bacterial symbiotic granular sludge. The COD concentration in the simulated wastewater was 500-550 mg / L, and the NH4+ concentration was... +The concentration of -N was 40-45 mg / L, TP was 6-8 mg / L, and Ca... 2+ The concentration is 80-100 mg / L; when the SBR reactor is running periodically, the running time of each cycle is 5-6 h; the anaerobic running time is 1-1.5 h, and the aeration running time is 3 h 50 min - 4 h 5 min; when aeration is running, an environment with a light intensity of 4000-4500 lux is provided simultaneously, and the aeration rate is 1-2 L / min.

[0021] Step 2: Use pure water to wash the stored bacterial and algae granular sludge 2-3 times to thoroughly remove residual nutrients and metabolic byproducts, eliminate unnecessary metabolic activities during storage, and induce microorganisms to enter a dormant state, thereby obtaining the washed bacterial and algae granular sludge.

[0022] Step 3: Measure the preset amount of tap water; introduce nitrogen gas into the tap water for 20-30 minutes to remove residual chlorine and oxygen from the tap water and obtain pretreated clean water.

[0023] Step 4: Add the cleaned algae and bacterial granular sludge to the pretreated clean water to form a mixed system; transfer the mixed system to a storage reactor and store it under a preset low temperature environment and a periodic light-dark alternation environment. The preset low temperature environment is 4±0.5℃; in the periodic light-dark alternation environment, the light-dark time ratio in each light-dark alternation cycle is 1:1, and the light intensity is 3000-4500 lux; preferably, in the periodic light-dark alternation environment, the light time in each light-dark alternation cycle is 6 hours, and the dark time is 6 hours.

[0024] Step 5: When reactivation of the stored algal granular sludge is required, remove the supernatant from the storage reactor and provide in-situ aeration and light treatment to obtain reactivated algal granular sludge. Specifically, remove the supernatant from the storage reactor; then, use simulated recovery wastewater as influent, and operate the storage reactor under in-situ aeration of 1-2 L / min and light irradiation of 3000-4500 lux to obtain reactivated algal granular sludge; wherein, the concentration of COD in the simulated recovery wastewater is 500-520 mg / L, and NH4+ is... + The concentration of -N was 35-40 mg / L, TP was 6-7 mg / L, and Ca... 2+ The concentration is 80-100 mg / L.

[0025] Storage and reactivation principles: The method for storing and reactivating granular sludge of bacteria and algae described in this invention involves obtaining the granular sludge to be stored by simply supplying light to the activated sludge to form mature symbiotic granular sludge, without the need for exogenous algae. Then, the mature symbiotic granular sludge is washed in pure water to thoroughly remove residual nutrients and metabolic byproducts, eliminating unnecessary metabolic activity during storage and inducing microorganisms into a dormant state. Next, during storage, a low-temperature environment is used to effectively reduce the metabolic rate of microorganisms and ensure the activity of the granular sludge. A periodic light-dark alternation environment is applied to match the survival needs of the algae, maintaining their physiological activity and functional stability. Based on the principle of synergistic regulation of environmental factors, this invention constructs a clear water storage medium, couples a low-temperature maintenance system with light-dark periodic regulation methods, and forms a synergistic preservation system. This allows the stored granular sludge of bacteria and algae to quickly restore its wastewater treatment efficiency while maintaining complete algal biomass, demonstrating significant advantages in maintaining the stability of the symbiotic system and improving functional recovery efficiency.

[0026] The following specific embodiments further explain the method for storing and reactivating granular sludge of bacteria and algae provided by the present invention: Example 1 This embodiment 1 provides a method for storing and reactivating granular sludge containing bacteria and algae, including the following steps: Step 1: Place the activated sludge in the SBR reactor and use simulated wastewater as the influent. The SBR reactor is run periodically until the algae-bacterial symbiotic granular sludge is formed. Then, it is transferred to a cylindrical glass reactor for continuous operation to obtain mature algae-bacterial symbiotic granular sludge.

[0027] The activated sludge was selected from the recycled activated sludge of the wastewater treatment plant. It was yellowish-brown in color, with an initial MLSS of 5.9 g / L and an SVI30 of 83.05 mL / g.

[0028] The concentration of COD in the simulated wastewater was 500 mg / L, and the concentration of NH4+ was... + The concentration of -N was 45 mg / L, TP was 6 mg / L, and Ca... 2+ The concentration is 100 mg / L; when the SBR reactor is running periodically, each cycle lasts for 6 hours; the anaerobic operation time is 1.5 hours, and the aeration operation time is 4 hours and 5 minutes; during aeration operation, a light environment of 4500 lux is provided simultaneously, and the aeration rate is controlled at 1 L / min.

[0029] Step 2: Wash the stored bacterial and algae granular sludge three times with pure water to thoroughly remove residual nutrients and metabolic byproducts, eliminate unnecessary metabolic activities during storage, and induce microorganisms to enter a dormant state, thereby obtaining the washed bacterial and algae granular sludge.

[0030] Step 3: Measure the preset amount of tap water; introduce nitrogen gas into the tap water for 25 minutes to remove residual chlorine and oxygen from the tap water and obtain pretreated clean water.

[0031] Step 4: Add the cleaned algae and bacterial granular sludge to the pretreated water to form a mixed system; transfer the mixed system to a photobioreactor and store it under a preset low-temperature environment with periodic light-dark alternation. The preset low-temperature environment is a periodic light-dark alternation environment at 4℃, with a light intensity of 4500 lux in each light-dark alternation cycle, a light duration of 6 hours, and a darkness duration of 6 hours in each light-dark alternation cycle.

[0032] Step 5: When reactivation of the stored algal granular sludge is required, remove the supernatant from the photobioreactor; then, using the simulated recovery wastewater as influent, operate the storage reactor under in-situ aeration of 1 L / min and 4500 lux of light to obtain reactivated algal granular sludge; wherein, the concentration of COD in the simulated recovery wastewater is 520 mg / L, and NH4+ is... + The concentration of -N was 40 mg / L, TP was 7 mg / L, and Ca... 2+ The concentration is 70 mg / L.

[0033] Comparative Example The method for storing and reactivating granular sludge provided in this comparative example differs from the method for storing and reactivating granular sludge described in Example 1 above in that: In the comparative example, the mixed system was transferred to a photobioreactor fully wrapped in aluminum foil to utilize the filter of the covering to block external light sources from penetrating the photobioreactor, thereby maintaining a dark environment during storage; as shown in the attached figure. Figure 1 As shown, attached Figure 1 Physical photographs of the storage reactors in Example 1 and the comparative example are provided in the appendix; Figure 1 As can be seen from the above, the storage reactor in Example 1 is an unobstructed photobioreactor, while the storage reactor in the comparative example is a photobioreactor completely wrapped in aluminum foil.

[0034] Example 2 This embodiment 2 provides a method for storing and reactivating bacterial and algal granular sludge, including the following steps: Step 1: Place the activated sludge in the SBR reactor and use simulated wastewater as the influent. The SBR reactor is run periodically until the algae-bacterial symbiotic granular sludge is formed. Then, it is transferred to a cylindrical glass reactor for continuous operation to obtain mature algae-bacterial symbiotic granular sludge.

[0035] The activated sludge was selected from the recycled activated sludge of the wastewater treatment plant. It was yellowish-brown in color, with an initial MLSS of 6.1 g / L and an SVI30 of 95.08 mL / g.

[0036] The concentration of COD in the simulated wastewater was 550 mg / L, and the concentration of NH4+ was... + The concentration of -N is 40 mg / L, TP is 8 mg / L, and Ca... 2+ The concentration is 80 mg / L; when the SBR reactor is running periodically, each cycle lasts for 5 hours; the anaerobic operation time is 1 hour, and the aeration operation time is 3 hours and 50 minutes; during the aeration operation, a light environment of 4000 lux is provided simultaneously, and the aeration rate is controlled at 2 L / min.

[0037] Step 2: Wash the stored bacterial and algae granular sludge twice with pure water to thoroughly remove residual nutrients and metabolic byproducts, eliminate unnecessary metabolic activities during storage, and induce microorganisms to enter a dormant state, thereby obtaining the washed bacterial and algae granular sludge.

[0038] Step 3: Measure the preset amount of tap water; introduce nitrogen gas into the tap water for 20 minutes to remove residual chlorine and oxygen from the tap water and obtain pretreated clean water.

[0039] Step 4: Add the cleaned algae and bacterial granular sludge to the pretreated clean water to form a mixed system; transfer the mixed system to a photobioreactor and store it under a preset low-temperature environment with periodic light-dark alternation. The preset low-temperature environment is a periodic light-dark alternation environment at 4.5℃, with a light intensity of 4000 lux in each light-dark alternation cycle, a light duration of 6 hours, and a darkness duration of 6 hours in each light-dark alternation cycle.

[0040] Step 5: When reactivation of the stored algal granular sludge is required, remove the supernatant from the photobioreactor; then, using the simulated recovery wastewater as influent, operate the storage reactor under in-situ aeration of 2 L / min and 4500 lux of light to obtain reactivated algal granular sludge; wherein, the concentration of COD in the simulated recovery wastewater is 500 mg / L, and NH4+ is... + The concentration of -N was 35 mg / L, TP was 6 mg / L, and Ca... 2+ The concentration is 80 mg / L.

[0041] Example 3 This embodiment 3 provides a method for storing and reactivating bacterial and algal granular sludge, including the following steps: Step 1: Place the activated sludge in the SBR reactor and use simulated wastewater as the influent. The SBR reactor is run periodically until the algae-bacterial symbiotic granular sludge is formed. Then, it is transferred to a cylindrical glass reactor for continuous operation to obtain mature algae-bacterial symbiotic granular sludge.

[0042] The activated sludge was selected from the recycled activated sludge of the wastewater treatment plant. It was yellowish-brown in color, with an initial MLSS of 5.5 g / L and an SVI30 of 87.27 mL / g.

[0043] The concentration of COD in the simulated wastewater was 520 mg / L, and the concentration of NH4+ was... + The concentration of -N was 42 mg / L, TP was 7 mg / L, and Ca... 2+ The concentration is 90 mg / L; when the SBR reactor is running periodically, the running time of each cycle is 5.5 h; the anaerobic running time is 1.5 h, and the aeration running time is 3 h 50 min; during the aeration running time, a light environment of 4300 lux is provided simultaneously, and the aeration rate is controlled at 1.7 L / min.

[0044] Step 2: Wash the stored bacterial and algae granular sludge three times with pure water to thoroughly remove residual nutrients and metabolic byproducts, eliminate unnecessary metabolic activities during storage, and induce microorganisms to enter a dormant state, thereby obtaining the washed bacterial and algae granular sludge.

[0045] Step 3: Measure the preset amount of tap water; introduce nitrogen gas into the tap water for 30 minutes to remove residual chlorine and oxygen from the tap water and obtain pretreated clean water.

[0046] Step 4: Add the cleaned algae and bacterial granular sludge to the pretreated clean water to form a mixed system; transfer the mixed system to a photobioreactor and store it under a preset low-temperature environment with periodic light-dark alternation. The preset low-temperature environment is a periodic light-dark alternation environment at 3.5℃, with a light intensity of 3000 lux in each light-dark alternation cycle, a light duration of 6 hours, and a darkness duration of 6 hours in each light-dark alternation cycle.

[0047] Step 5: When reactivation of the stored algal granular sludge is required, remove the supernatant from the photobioreactor; then, using the simulated recovery wastewater as influent, operate the storage reactor under in-situ aeration of 1.7 L / min and 3000 lux of light to obtain reactivated algal granular sludge; wherein, the concentration of COD in the simulated recovery wastewater is 510 mg / L, and NH4+ is... + The concentration of -N was 37 mg / L, TP was 6.5 mg / L, and Ca... 2+ The concentration is 90 mg / L.

[0048] Example 4 This embodiment 4 provides a method for storing and reactivating granular sludge containing bacteria and algae, including the following steps: Step 1: Place the activated sludge in the SBR reactor and use simulated wastewater as the influent. The SBR reactor is run periodically until the algae-bacterial symbiotic granular sludge is formed. Then, it is transferred to a cylindrical glass reactor for continuous operation to obtain mature algae-bacterial symbiotic granular sludge.

[0049] The activated sludge was selected from the recycled activated sludge of the wastewater treatment plant. It was yellowish-brown in color, with an initial MLSS of 5.6 g / L and an SVI30 of 85.71 mL / g.

[0050] The concentration of COD in the simulated wastewater was 530 mg / L, and the concentration of NH4+ was... + The concentration of -N was 45 mg / L, TP was 7.5 mg / L, and Ca... 2+ The concentration is 85 mg / L; when the SBR reactor is running periodically, each cycle lasts for 6 hours; the anaerobic operation time is 1.5 hours, and the aeration operation time is 4 hours and 5 minutes; during the aeration operation, a light environment of 4100 lux is provided simultaneously, and the aeration rate is controlled at 1.5 L / min.

[0051] Step 2: Wash the stored bacterial and algae granular sludge twice with pure water to thoroughly remove residual nutrients and metabolic byproducts, eliminate unnecessary metabolic activities during storage, and induce microorganisms to enter a dormant state, thereby obtaining the washed bacterial and algae granular sludge.

[0052] Step 3: Measure the preset amount of tap water; introduce nitrogen gas into the tap water for 25 minutes to remove residual chlorine and oxygen from the tap water and obtain pretreated clean water.

[0053] Step 4: Add the cleaned algae and bacterial granular sludge to the pretreated clean water to form a mixed system; transfer the mixed system to a photobioreactor and store it under a preset low-temperature environment with periodic light-dark alternation. The preset low-temperature environment is a periodic light-dark alternation environment at 4℃, with a light intensity of 4100 lux in each light-dark alternation cycle, a light duration of 6 hours, and a darkness duration of 6 hours in each light-dark alternation cycle.

[0054] Step 5: When reactivation of the stored algal granular sludge is required, remove the supernatant from the photobioreactor; then, using the simulated recovery wastewater as influent, operate the storage reactor under in-situ aeration of 1.5 L / min and 3000 lux of light to obtain reactivated algal granular sludge; wherein, the concentration of COD in the simulated recovery wastewater is 500 mg / L, and NH4+ is... + The concentration of -N was 40 mg / L, TP was 7 mg / L, and Ca... 2+ The concentration is 80 mg / L.

[0055] Example 5 This embodiment 5 provides a method for storing and reactivating granular sludge containing bacteria and algae, including the following steps: Step 1: Place the activated sludge in the SBR reactor and use simulated wastewater as the influent. The SBR reactor is run periodically until the algae-bacterial symbiotic granular sludge is formed. Then, it is transferred to a cylindrical glass reactor for continuous operation to obtain mature algae-bacterial symbiotic granular sludge.

[0056] The activated sludge was selected from the recycled activated sludge of the wastewater treatment plant. It was yellowish-brown in color, with an initial MLSS of 5.6 g / L and an SVI30 of 83.33 mL / g.

[0057] The concentration of COD in the simulated wastewater was 550 mg / L, and the concentration of NH4+ was... + The concentration of -N was 45 mg / L, TP was 7 mg / L, and Ca... 2+ The concentration is 100 mg / L; when the SBR reactor is running periodically, the running time of each cycle is 6 h; the anaerobic running time is 1.5 h, and the aeration running time is 4 h 5 min; during the aeration running time, a light environment of 4000 lux is provided simultaneously, and the aeration rate is controlled at 1.5 L / min.

[0058] Step 2: Wash the stored bacterial and algae granular sludge three times with pure water to thoroughly remove residual nutrients and metabolic byproducts, eliminate unnecessary metabolic activities during storage, and induce microorganisms to enter a dormant state, thereby obtaining the washed bacterial and algae granular sludge.

[0059] Step 3: Measure the preset amount of tap water; introduce nitrogen gas into the tap water for 20 minutes to remove residual chlorine and oxygen from the tap water and obtain pretreated clean water.

[0060] Step 4: Add the cleaned algae and bacterial granular sludge to the pretreated clean water to form a mixed system; transfer the mixed system to a photobioreactor and store it under a preset low-temperature environment with periodic light-dark alternation. The preset low-temperature environment is a periodic light-dark alternation environment at 4.5℃, with a light intensity of 4000 lux in each light-dark alternation cycle, a light duration of 6 hours, and a darkness duration of 6 hours in each light-dark alternation cycle.

[0061] Step 5: When reactivation of the stored algal granular sludge is required, remove the supernatant from the photobioreactor; then, using the simulated recovery wastewater as influent, operate the storage reactor under in-situ aeration of 1.5 L / min and 4500 lux of light to obtain reactivated algal granular sludge; wherein, the concentration of COD in the simulated recovery wastewater is 520 mg / L, and NH4+ is... +The concentration of -N was 40 mg / L, TP was 6.5 mg / L, and Ca... 2+ The concentration is 100 mg / L.

[0062] Performance testing: The stored bacterial and algal granular sludge from Examples 1-5 and the comparative examples was reactivated, and the morphology, COD, and NH4 content of the reactivated bacterial and algal granular sludge from Examples 1-5 and the comparative examples were analyzed. + The removal effect of -N was tested.

[0063] The specific testing process is as follows: The effluent from the reaction cycle was pretreated. The treatment process involved filtering the water sample through a 0.45 μm filter membrane to check COD and NH4. + -N was obtained using the dichromate method and Nessler's reagent method, respectively.

[0064] The morphology of the bacterial and algal granular sludge before and after storage was collected using a portable digital imaging device.

[0065] Test results showed that when the stored bacterial and algal granular sludge from Examples 1-5 was reactivated for 15-20 days, COD and NH4 levels could be restored. + The removal effect of -N was improved, and the removal effect could be restored to more than 90% of the removal effect before the storage of bacterial and algae granular sludge; while the recovery effect of the bacterial and algae granular sludge stored in the comparative example after 20 days of reactivation was far lower than that of Example 1, and the recovery rate was also low.

[0066] Specifically, the stored bacterial and algal granular sludge in Example 1 has a positive effect on COD and NH4. + The removal efficiency of -N can be restored to more than 90% of the removal efficiency before storage of the bacterial and algae granular sludge within 15 days, and the bacterial and algae granular sludge can show excellent removal efficiency in the initial stage of the recovery period; at the same time, the reactivated bacterial and algae granular sludge can maintain a good biomass of algae. The bacterial and algae granular sludge stored in Example 2 effectively reduced COD and NH4 levels. + The removal efficiency of -N can be restored to more than 90% of the removal efficiency before storage of the bacterial and algae granular sludge within 20 days. In Example 3, the stored bacterial and algae granular sludge showed improved performance in removing COD and NH4+. + The removal efficiency of -N can be restored to more than 90% of the removal efficiency before storage of the bacterial and algae granular sludge within 18 days. In Example 4, the stored bacterial and algae granular sludge showed improved performance in COD and NH4+ removal. + The removal efficiency of -N was restored to over 90% of the effect before storage of the algae-bacterial granular sludge within 19 days. In Example 5, the stored algae-bacterial granular sludge showed improved performance in removing COD and NH4+. +The removal effect of -N can restore more than 90% of the removal effect before the storage of bacterial and algal granular sludge within 22 days.

[0067] As attached Figure 2-3 As shown, attached Figure 2 The document provides photographs of the bacterial and algal granular sludge before storage in Example 1, with accompanying images. Figure 3 The attached document provides photographs of the stored algal granular sludge from Example 1; Figure 2 As can be seen, the granular sludge containing bacteria and algae maintained a relatively intact structure before storage; from the attached... Figure 3 As can be seen from the attached Figure 2 Compared to the granular sludge of bacteria and algae before storage, the attached... Figure 3 Although some filamentous algae expanded and proliferated in the stored bacterial and algal granular sludge, it still maintained a relatively good sludge structure.

[0068] As attached Figure 4 As shown, attached Figure 4 The figure shows the COD removal effect curve of the bacterial and algal granular sludge in the in-situ recovery period in Example 1; from the attached figure Figure 4 As can be seen, the COD removal rate of the stored and in-situ restored bacterial and algal granular sludge exceeded 90% after 15 days and remained stable.

[0069] As attached Figure 5 As shown, attached Figure 5 The example provided illustrates the removal of NH4 by granular sludge from algae and bacteria during the in-situ recovery period in Example 1. + The effect curve of -N; from the attached... Figure 5 It can be seen that after 7 days, the activated bacterial and algal granular sludge has low NH4 content. + The -N removal rate reached 100%, demonstrating excellent nitrification function.

[0070] As attached Figure 6 As shown, attached Figure 6 The figure shows the change curve of chlorophyll content before and after storage of the bacterial and algal granular sludge in Example 1; from the appendix Figure 6 As can be seen, although chlorophyll decreased significantly after storage, chlorophyll increased rapidly during the recovery period, indicating that the storage strategy did not affect the algal life activities during the recovery period.

[0071] As attached Figure 7 As shown, attached Figure 7 The accompanying image shows photographs of the stored bacterial and algal granular sludge from the comparative example; from the attached image... Figure 7 As can be seen, compared with before storage, the bacterial and algal granular sludge after storage has fine particles, indicating that there is a disintegration of the granular sludge structure.

[0072] As attached Figure 8 As shown, attached Figure 8 The figure shows the COD removal effect curve of the bacterial and algal granular sludge in the in-situ recovery period in the comparative example; from the appendix Figure 8 As can be seen, although the restored bacterial and algal granular sludge maintained a high COD removal efficiency, a relatively obvious fluctuation occurred at 15 days.

[0073] As attached Figure 9 As shown, attached Figure 9 The paper presents a comparative example of NH4 removal by granular sludge from algae and bacteria during the in-situ recovery period. + The effect curve of -N; from the attached... Figure 9 As can be seen, compared with the efficient recovery of nitrification function in Example 1, the bacterial and algal granular sludge in this comparative example has a consistently poor effect on ammonia nitrogen removal, indicating that the nitrification function may require a longer recovery time.

[0074] As attached Figure 10 As shown, attached Figure 10 The figure shows the change curves of chlorophyll content before and after storage of the bacterial and algal granular sludge in the comparative example; from the appendix... Figure 10 As can be seen, although the chlorophyll reduction was less when the proportional storage strategy was adopted, considering the overall structure of the bacterial and algal granular sludge and its pollutant removal effect, the proportional storage strategy could not effectively balance the cooperative relationship between bacteria and algae, resulting in poor pollutant removal effect of the bacterial and algal granular sludge during the recovery period.

[0075] The method for storing and reactivating granular sludge of bacteria and algae described in this invention is based on the principle of synergistic regulation of environmental factors. It constructs a low-temperature-dark cycle environment, forming a synergistic preservation system that couples a clean water storage medium with a low-temperature maintenance system and a light-dark cycle regulation. This allows the bacteria-algae system to rapidly restore its wastewater treatment efficiency after storage, while maintaining complete algal biomass. Specifically, the low-temperature environment effectively reduces the metabolic rate of microorganisms, ensuring the activity of the granular sludge; the light-dark cycle matches the survival needs of algae, maintaining their physiological activity and functional stability. This invention effectively fills the technical gap in dedicated storage methods for granular sludge of bacteria and algae, demonstrating significant advantages over conventional microbial preservation methods in maintaining the stability of the symbiotic system and improving functional recovery efficiency. It should be noted that the bacteria involved in this invention are all common species in the field and are not the focus of this application; therefore, they will not be elaborated upon here.

[0076] The above embodiments are merely one of the implementation methods for achieving the technical solution of the present invention. The scope of protection claimed by the present invention is not limited to this embodiment, but also includes any variations, substitutions and other implementation methods that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention.

Claims

1. A method for storing and reactivating granular sludge containing bacteria and algae, characterized in that, include: The stored bacterial and algae granular sludge was washed with pure water to obtain the washed bacterial and algae granular sludge. Pretreated clean water and washed algae granular sludge are added to the storage reactor and stored in a preset low-temperature environment with periodic light and dark alternation. When it is necessary to reactivate the stored bacterial and algal granular sludge, the supernatant in the storage reactor is removed, and aeration and light are provided in situ to obtain reactivated bacterial and algal granular sludge.

2. The method for storing and reactivating granular sludge of bacteria and algae according to claim 1, characterized in that, The bacterial and algae granular sludge to be stored is a mature bacterial and algae symbiotic granular sludge. The preparation process of mature algae-microbe symbiotic granular sludge includes: Activated sludge is placed in an SBR reactor, using simulated wastewater as influent. The SBR reactor is run periodically until algae-bacterial symbiotic granular sludge is formed. Then, it is transferred to a cylindrical glass reactor for continuous operation to obtain mature algae-bacterial symbiotic granular sludge.

3. The method for storing and reactivating granular sludge of bacteria and algae according to claim 2, characterized in that, The concentration of COD in the simulated wastewater was 500-550 mg / L, and the concentration of NH4+ was... + The concentration of -N was 40-45 mg / L, TP was 6-8 mg / L, and Ca... 2+ The concentration is 80-100 mg / L.

4. The method for storing and reactivating granular sludge of bacteria and algae according to claim 2, characterized in that, When the SBR reactor is operated in a periodic manner, the operating time of each operating cycle is 5-6 hours. Within each operating cycle, the anaerobic operation time is 1-1.5 hours, and the aeration operation time is 3 hours 50 minutes to 4 hours 5 minutes. During the aeration operation, an environment with a light intensity of 4000-4500 lux is provided simultaneously, and the aeration rate is 1-2 L / min.

5. The method for storing and reactivating granular sludge of bacteria and algae according to claim 1, characterized in that, The process of preparing pretreated clean water includes: Nitrogen gas is introduced into tap water to remove residual chlorine and oxygen, resulting in pretreated clean water; the nitrogen gas is introduced for 20-30 minutes.

6. The method for storing and reactivating granular sludge of bacteria and algae according to claim 1, characterized in that, The preset low temperature environment is 4±0.5℃.

7. The method for storing and reactivating granular sludge of bacteria and algae according to claim 1, characterized in that, In a periodic light-dark alternation environment, the light-dark time ratio in each light-dark alternation cycle is 1:1, and the light intensity is 3000-4500 lux.

8. The method for storing and reactivating granular sludge of bacteria and algae according to claim 7, characterized in that, In a periodic light-dark environment, the light duration is 6 hours and the darkness duration is 6 hours in each light-dark cycle.

9. The method for storing and reactivating granular sludge of bacteria and algae according to claim 1, characterized in that, When it is necessary to reactivate the stored bacterial and algal granular sludge, the supernatant in the storage reactor is removed, and in-situ aeration and light treatment are provided to obtain reactivated bacterial and algal granular sludge, as follows: Remove the supernatant from the storage reactor; then, use the restored simulated wastewater as influent, and run the storage reactor under in-situ aeration of 1-2 L / min and light of 3000-4500 lux to obtain reactivated bacterial and algal granular sludge.

10. A method for storing and reactivating granular sludge of bacteria and algae according to claim 9, characterized in that, The COD concentration in the simulated wastewater was then restored to 500-520 mg / L, and the NH4+ concentration was... + The concentration of -N was 35-40 mg / L, TP was 6-7 mg / L, and Ca... 2+ The concentration is 80-100 mg / L.

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