Method for rapidly culturing bacteria-algae granular sludge at low superficial gas velocity

Abstract

The invention relates to the technical field of sewage treatment, and discloses a method for quickly culturing bacteria-algae granular sludge at low superficial gas velocity, comprising a water inlet tank for storing sewage to be treated; the water inlet pipe is connected with the water inlet tank, the water inlet pipe introduces sewage into the reactor through a peristaltic pump, and the peristaltic pump is controlled by an electronic relay to start and stop; the height-diameter ratio of the reactor is greater than 12.5, the interior of the reactor is used for culturing the bacteria-algae granular sludge, and the reactor is a place for removing pollutants from the bacteria-algae granular sludge; the nano-membrane aeration assembly is arranged at the bottom of the reactor and is used for supplementing oxygen required by metabolism of aerobic microorganisms; the water outlet pipe is connected with the reactor. According to the present invention, through the high height-diameter ratio of the reactor, the nanometer film aeration mode and the accurate regulation and control of the operation parameters, the rapid culture of the bacteria-algae granular sludge can be achieved at the low superficial gas velocity, and compared with the traditional high superficial gas velocity culture mode, the process energy consumption is significantly reduced, and the low-carbon operation of the sewage treatment is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment, and in particular to a method for rapidly culturing bacteria and algae granular sludge at low superficial gas velocity. Background Art

[0002] The bacterial-algae symbiotic system is a new type of sewage treatment technology, that is, under light, microalgae use nitrogen and phosphorus in sewage to synthesize their own cell substances through photosynthesis, and release oxygen for bacteria to use, while bacteria degrade organic matter and synthesize nutrients required by microalgae. The bacterial-algae symbiotic system can not only efficiently remove organic matter and nitrogen and phosphorus in wastewater through the symbiotic relationship between microorganisms, but also reduce energy consumption, so it has attracted much attention. Granular sludge has high biomass and compact spatial structure, which can cope with high pollutant loads and reduce the diffusion of toxic substances. In addition, the different microenvironments inside the granular sludge can provide a suitable place for the symbiosis of bacteria and algae. In summary, bacterial-algae granular sludge is a more efficient technology with broad application prospects. Although many scholars have achieved granulation of bacterial-algae granular sludge by adjusting light intensity, increasing weak static magnetic field or signal molecules, this is based on high superficial air velocity. High superficial air velocity requires high aeration intensity to achieve high shear force and suitable dissolved oxygen, which makes energy consumption too large and does not meet the existing low-carbon requirements.

[0003] To this end, those skilled in the art have proposed a method for rapidly culturing bacteria and algae granular sludge at low superficial gas velocity to solve the above problems. Summary of the invention

[0004] In view of the deficiencies of the prior art, the present invention provides a method for rapidly culturing bacteria and algae granular sludge at low superficial gas velocity, which solves the problems raised in the above-mentioned background technology.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: a device for rapidly culturing bacteria and algae granular sludge at low superficial gas velocity, comprising:

[0006] Inlet tank for storing sewage to be treated;

[0007] A water inlet pipe connected to the water inlet tank, the water inlet pipe is connected to a peristaltic pump to introduce sewage into the reactor, the peristaltic pump is started and stopped by an electronic relay to control the water inlet flow rate and water inlet time;

[0008] The reactor has a height-to-diameter ratio greater than 12.5, and is used to cultivate bacteria-algae granular sludge. It is a place for bacteria-algae granular sludge to remove pollutants. The reactor has a longer sedimentation zone, which can effectively discharge flocculent sludge by shortening the sedimentation time, and accelerate the granulation process of the sludge. The oxygen produced by the metabolism of Chlorella in the reactor can be used for the metabolism of aerobic microorganisms, reducing the demand for aeration and oxygen supplementation. The nano-membrane aeration disk is placed at the bottom of the reactor to supplement the oxygen required for the metabolism of aerobic microorganisms.

[0009] The outlet pipe is connected to the reactor and discharges the treated sewage out of the reactor through peristalsis. The peristalsis is controlled by an electronic relay to start and stop, and is used to adjust the sewage discharge flow and time of the reaction to ensure the stability of the water quality in the reactor and the treatment efficiency.

[0010] An aeration pump, the outside of which is connected to an aeration pipe, the aeration pipe is connected to the nano-membrane aeration at the bottom of the reaction, and the aeration is started and stopped by an electronic relay to ensure that the dissolved oxygen concentration in the reaction is maintained within the required range;

[0011] The dissolved oxygen probe is arranged inside the reactor and is used to monitor the dissolved oxygen concentration in the reactor in real time.

[0012] Preferably, the water temperature of the reactor is controlled at 27±2°C to maintain an optimal growth environment for microalgae and bacteria. In addition, the reactor is given a light intensity of 6500±200lx, and an alternating light cycle of 12 hours of light and 12 hours of darkness is set.

[0013] Preferably, the water outlet pipe is installed at 1 / 2 of the total height of the reactor.

[0014] Preferably, the nanobubbles formed by the nanomembrane aeration disk can improve the efficiency of dissolved oxygen.

[0015] A method for rapidly culturing bacteria-algae granular sludge at low superficial gas velocity comprises the following steps:

[0016] Step 1: Inoculate the reactor with sludge at a concentration of 4 g / L, and control the ratio of sludge concentration to Chlorella concentration to be 3:1;

[0017] Step 2: During the startup phase, set the cycle to 4-5 hours, including 5-10 minutes of water inlet, 55-70 minutes of anaerobic treatment, 145-180 minutes of aeration, 30-45 minutes of sedimentation, and 5-12 minutes of water outlet;

[0018] Step 3: In the first 4 days, extend the sedimentation time as much as possible to prevent the loss of algae and sludge. Then shorten the sedimentation time by 5-8 minutes and increase the aeration time by 5 minutes every 5 days. Finally, shorten the sedimentation time to 5-6 minutes and increase the aeration time to 170-210 minutes.

[0019] Preferably, in steps 1 to 3, the volume exchange ratio of each cycle is not less than 50%.

[0020] Preferably, the superficial gas velocity of the entire process from step 1 to step 3 is always maintained at 0.6-0.7 cm / s, the aeration intensity is between 1.8-2.0 L / min, and the dissolved oxygen concentration in the reactor is between 6.0-6.5 mg / L.

[0021] Preferably, the sedimentation time in step three is maintained at 5-8 minutes, and through the above method, the granulation process of bacteria and algae granular sludge can be completed within 35 days.

[0022] The invention provides a method for rapidly culturing bacteria and algae granular sludge at low superficial gas velocity.

[0023] It has the following beneficial effects:

[0024] 1. The present invention can achieve rapid cultivation of bacteria and algae granular sludge at low superficial gas velocity through the high aspect ratio of the reactor and nano-membrane aeration, which significantly reduces the demand for aeration intensity compared to traditional high superficial gas velocity treatment technologies. In the past, high superficial gas velocity usually requires high-intensity aeration equipment, resulting in increased energy consumption. The aeration intensity of this method is only 1.8-2.0L / min, and the superficial gas velocity is maintained at 0.6-0.7cm / s, which achieves the cultivation of bacteria and algae granular sludge and effectively reduces process energy consumption. This energy-saving feature not only reduces operating costs, but also makes this method more in line with the requirements of modern environmental protection and sustainable development, and meets current energy-saving standards.

[0025] 2. The present invention achieves granulation of bacterial and algae sludge by precisely controlling various operating parameters of the reactor. The formation of granular sludge not only improves the biomass and sedimentation of sewage treatment, but its internal diversified micro-region environment also provides a suitable space for the symbiosis of bacteria and microalgae, allowing the two to better rely on each other, thereby improving the treatment efficiency of the entire system for organic matter, nitrogen, phosphorus and other pollutants. In addition, the high sedimentation of granular sludge can also reduce secondary pollution, reduce the complexity of subsequent treatment, and improve the stability and reliability of the overall sewage treatment system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the working state structure of the present invention;

[0027] Figure 2 This is a diagram showing the pollutant removal capability of an embodiment of the present invention;

[0028] Figure 3 This is a diagram showing the sludge characteristic treatment effect of an embodiment of the present invention.

[0029] Among them, 1. Water inlet tank; 2. Water inlet pipe; 3. Aeration pump; 4. Aeration pipe; 5. Reactor; 6. Dissolved oxygen probe; 7. Bacteria and algae granular sludge; 8. Nano membrane aeration plate; 9. Water outlet pipe; 10. Peristaltic pump; 11. Electronic relay. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Please refer to the attached Figure 1 - Attachment Figure 3 The embodiment of the present invention provides a device for rapidly culturing bacteria and algae granular sludge at a low superficial gas velocity, comprising:

[0032] A water inlet tank 1, used for storing sewage to be treated;

[0033] The water inlet pipe 2 connects the water inlet tank 1 and the reactor 5. The water inlet pipe 2 is connected to a peristaltic pump 10. The start and stop of the peristaltic pump 10 is controlled by an electronic relay 11 to introduce sewage into the reactor 5.

[0034] The reactor 5 has a height-to-diameter ratio greater than 12.5, and is used to cultivate bacteria-algae granular sludge 7 inside. It is a place for bacteria-algae granular sludge to remove pollutants. The reactor has a longer sedimentation zone, which can effectively discharge flocculent sludge by shortening the sedimentation time, and accelerate the granulation process of the sludge. The oxygen produced by the metabolism of Chlorella in the reactor 5 can be used for the metabolism of aerobic microorganisms, thereby reducing the demand for aeration and oxygen supplementation. The nano-membrane aeration plate 8 is placed at the bottom of the reactor 5 to supplement the oxygen required for the metabolism of aerobic microorganisms.

[0035] The outlet pipe 9 is connected to 1 / 2 of the total height of the reactor 5. The outlet pipe 9 is connected to a peristaltic pump 10. The start and stop of the peristaltic pump 10 is controlled by an electronic relay 11 to discharge the sewage from the reactor 5.

[0036] The aeration pump 3 delivers air to the nano-membrane aeration plate 8 at the bottom of the reactor 5 through the aeration pipe 4. The nano-bubbles formed by the nano-membrane aeration plate 8 can improve the dissolved oxygen efficiency. The aeration pump 3 is started and stopped by the electronic relay 11 to ensure that the dissolved oxygen concentration in the reactor 5 is maintained within a suitable range.

[0037] The dissolved oxygen probe 6 is disposed inside the reactor 5 and is used to monitor the dissolved oxygen concentration in the reactor in real time.

[0038] The water temperature of reactor 5 was controlled at 27±2°C to maintain the best growth environment for microalgae and bacteria. In addition, the reactor was given a light intensity of 56500±200 lx, and an alternating light cycle of 12 hours of light and 12 hours of darkness was set.

[0039] Specifically, the height-to-diameter ratio of the reactor 5 is greater than 12.5, so that the flocculent sludge can be effectively discharged by shortening the sedimentation time, accelerating the granulation process of the sludge. The sewage to be treated flows into the reactor 5 from the water inlet tank 1 through the water inlet pipe 2, ensuring that it is fully stirred before entering the reactor 5 to achieve uniform distribution of components. The design of the nano-membrane aeration plate 8 makes the dissolved oxygen evenly distributed, increases the contact area between the gas and the sewage, improves the dissolved oxygen efficiency, and achieves higher dissolved oxygen in the water under low aeration energy consumption. Under the set water temperature of 27±2℃ and the environment of suitable dissolved oxygen concentration, the bacterial and algae granular sludge 7 in the reactor proliferates rapidly, enhancing the removal ability of organic matter and pollutants such as nitrogen and phosphorus in the sewage. The dissolved oxygen probe 6 monitors the dissolved oxygen concentration in the reactor in real time, and automatically adjusts the aeration intensity according to the monitoring data to ensure the best microbial growth environment and treatment efficiency.

[0040] Key Benefits:

[0041] Energy saving and high efficiency: The oxygen produced by the metabolism of microalgae and the high dissolved oxygen efficiency of nano-membrane aeration can still meet the dissolved oxygen required for aerobic microbial metabolism at low superficial gas velocity, which not only reduces energy consumption, but also reduces operating costs.

[0042] Environmentally friendly: Algae outbreaks usually produce algal blooms, which may lead to eutrophication and deterioration of water quality. However, collecting and utilizing algae can effectively reduce the impact of algal blooms on water bodies.

[0043] A method for rapidly culturing bacteria-algae granular sludge at low superficial gas velocity comprises the following steps:

[0044] Step 1, inoculating sludge into the reactor 5 at a concentration of 4 g / L, and controlling the ratio of sludge concentration to Chlorella concentration to be 3:1;

[0045] Step 2: During the startup phase, set the cycle to 4-5 hours, including 5-10 minutes of water inlet, 55-70 minutes of anaerobic treatment, 145-180 minutes of aeration, 30-45 minutes of sedimentation, and 5-12 minutes of water outlet;

[0046] Step 3: In the first 4 days, extend the sedimentation time as much as possible to prevent the loss of algae and sludge. Then shorten the sedimentation time by 5-8 minutes and increase the aeration time by 5 minutes every 5 days. Finally, shorten the sedimentation time to 5-6 minutes and increase the aeration time to 170-210 minutes.

[0047] Specific advantages:

[0048] Optimize growth conditions: By controlling the ratio of sludge to Chlorella, an environment conducive to symbiosis is created, promoting the rapid growth of bacteria and algae particles.

[0049] Flexible operation cycle: Setting a reasonable cycle can maximize the treatment efficiency of each stage, thereby improving the stability of the entire sewage treatment process.

[0050] Continuous monitoring and adjustment: Dynamic adjustment of the settling time and aeration time in the method can adapt to the needs of microorganisms at different stages and optimize the treatment effect.

[0051] High-efficiency decontamination capability: Through efficient aeration, the pollutant degradation capability of aerobic bacteria is enhanced, thus improving the effluent quality.

[0052] In steps 1 to 3, the volume exchange ratio of each cycle is not less than 50%.

[0053] In the entire process from step 1 to step 3, the superficial gas velocity is maintained at 0.6 cm / s, and the aeration intensity is between 1.8-2.0 L / min, ensuring that the dissolved oxygen concentration in the reactor is between 6.0 mg / L.

[0054] The following table is an example table of reaction time comparison. The table shows the changes in culture time and main operating parameters under different conditions, and focuses on comparing the differences in reaction time, aeration time, sedimentation time, etc. between the traditional method and the method of the present invention in the culture process of algae granular sludge.

[0055] Table 1:

[0056]

[0057]

[0058] Conclusion: As shown in Table 1, by optimizing the operation cycle and adjusting the aeration and sedimentation time, stable bacterial and algal granular sludge can be quickly cultivated within 35 days, while the traditional method requires 40-45 days using low superficial air velocity and low aeration intensity, effectively reducing energy consumption and operating costs.

[0059] In summary: The present invention uses low superficial air velocity to cultivate bacterial and algal granular sludge 7, which significantly reduces the dependence on aeration intensity compared to traditional high superficial air velocity treatment technology. High superficial air velocity usually requires stronger aeration equipment, resulting in increased energy consumption, while the present method controls the aeration intensity at 1.8-2.0L / min and the superficial air velocity at 0.6-0.7cm / s, effectively reducing energy consumption. This energy-saving feature not only reduces operating costs, but also makes the method more in line with modern environmental protection and sustainable development standards.

[0060] In addition, the present invention effectively promotes the generation of bacterial and algae granular sludge 7 by precisely controlling various parameters in the reactor. The formation of granular sludge improves the biomass and sedimentation of sewage treatment, while optimizing the symbiotic relationship between microalgae and bacteria, and enhancing the removal efficiency of organic matter and pollutants such as nitrogen and phosphorus in sewage. The diversified microenvironment inside the granular sludge creates an ideal space for the symbiosis of bacteria and algae, enhances their mutual dependence, and thus improves the overall treatment efficiency. In addition, the excellent sedimentation of granular sludge helps to reduce secondary pollution, simplify subsequent treatment processes, and improve the stability and reliability of the entire sewage treatment system. At the same time, compared with the currently reported bacterial and algae granular sludge culture time of 40-45 days, the treatment method of the present invention can achieve the cultivation of bacterial and algae granular sludge in 35 days under low superficial gas velocity conditions, and the cultured bacterial and algae granular sludge has a stable structure and a strong pollutant removal ability.

[0061] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A device for rapidly culturing bacteria and algae granular sludge at low superficial gas velocity, characterized in that: include: A water inlet tank (1) for storing sewage to be treated; A water inlet pipe (2) is connected to the water inlet tank (1), and the water inlet pipe (2) is connected to a peristaltic pump (10) to introduce sewage into the interior of the reactor. The peristaltic pump (10) is controlled to start and stop by an electronic relay (11) to control the water inlet flow rate and water inlet time; The reactor (5) has a height-to-diameter ratio greater than 12.5, and is used to cultivate bacterial and algae granular sludge (7) inside. It is a place for bacterial and algae granular sludge to remove pollutants. The reactor has a longer sedimentation zone, and can effectively discharge flocculent sludge by shortening the sedimentation time, thereby accelerating the granulation process of the sludge. Inside the reactor (5), oxygen produced by the metabolism of Chlorella can be used for the metabolism of aerobic microorganisms, thereby reducing the demand for aeration and oxygen supplementation. The nano-membrane aeration disk (8) is placed at the bottom of the reactor (5) to supplement the oxygen required for the metabolism of aerobic microorganisms. The water outlet pipe (9) is connected to the reactor (5) and discharges the treated sewage out of the reactor (5) via a peristaltic pump (10). The peristaltic pump (10) is started and stopped by an electronic relay (11) and is used to adjust the sewage discharge flow rate and time of the reactor (5) to ensure the stability of the water quality and the treatment efficiency in the reactor (5). An aeration pump (3) is externally connected to an aeration pipe (4), wherein the aeration pipe (4) is connected to a nano-membrane aeration plate (8) at the bottom of the reactor (5), and the aeration pump (3) is controlled to start and stop by an electronic relay (11) to ensure that the dissolved oxygen concentration in the reactor (5) is maintained within a desired range; The dissolved oxygen probe (6) is arranged inside the reactor (5) and is used to monitor the dissolved oxygen concentration in the reactor in real time.

2. The device for rapidly culturing bacteria and algae granular sludge at low superficial gas velocity according to claim 1, characterized in that: The water temperature of the reactor (5) is controlled at 27±2°C to maintain an optimal growth environment for microalgae and bacteria. In addition, the reactor (5) is provided with a light intensity of 6500±200 lx, and an alternating light cycle of 12 hours of light and 12 hours of darkness is set.

3. The device for rapidly culturing bacteria and algae granular sludge at low superficial gas velocity according to claim 1, characterized in that: The water outlet pipe (9) is installed at 1 / 2 of the total height of the reactor (5).

4. The device for rapidly culturing bacteria and algae granular sludge at low superficial gas velocity according to claim 1, characterized in that: The nanometer bubbles formed by the nanometer membrane aeration disk (8) can improve the efficiency of oxygen dissolution.

5. A method for rapidly culturing bacteria and algae granular sludge at low superficial gas velocity, according to a device for rapidly culturing bacteria and algae granular sludge at low superficial gas velocity as described in any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1, inoculating sludge into the reactor (5) at a concentration of 4 g / L, and controlling the ratio of sludge concentration to Chlorella concentration to be 3:1; Step 2: During the startup phase, set the cycle to 4-5 hours, including 5-10 minutes of water inlet, 55-70 minutes of anaerobic treatment, 145-180 minutes of aeration, 30-45 minutes of sedimentation, and 5-12 minutes of water outlet; Step 3: In the first 4 days, extend the sedimentation time as much as possible to prevent the loss of algae and sludge. Then shorten the sedimentation time by 5-8 minutes and increase the aeration time by 5 minutes every 5 days. Finally, shorten the sedimentation time to 5-6 minutes and increase the aeration time to 170-210 minutes.

6. The method for rapidly culturing bacteria and algae granular sludge at low superficial gas velocity according to claim 5, characterized in that: In the steps 1 to 3, the volume exchange ratio of each cycle is not less than 50%.

7. The method for rapidly culturing bacteria and algae granular sludge at low superficial gas velocity according to claim 5, characterized in that: The superficial gas velocity of the entire process from step 1 to step 3 is always maintained at 0.6-0.7 cm / s, the aeration intensity is between 1.8-2.0 L / min, and the dissolved oxygen concentration in the reactor is between 6.0-6.5 mg / L.

8. The method for rapidly culturing bacteria and algae granular sludge at low superficial gas velocity according to claim 5, characterized in that: The sedimentation time in step three is maintained at 5-8 minutes, and through the above method, the granulation process of bacteria and algae granular sludge can be completed within 35 days.

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