A high-efficiency acidic nitritation treatment process and device for ammonia-containing wastewater

Abstract

The present invention discloses a high-efficiency acidic nitrosation treatment process and device for ammonia-containing sewage, and relates to the technical field of sewage treatment. The high-efficiency acidic nitrosation treatment process for ammonia-containing sewage of the present invention comprises: (1) acidic nitrification treatment: continuously introducing ammonia-containing sewage into a continuous flow reactor inoculated with aerobic granular sludge to carry out microbial nitrification reaction, and adjusting the pH by limiting the addition of alkali compounds to achieve an acidic nitrification treatment process; (2) rapid acidic nitrosation; and (3) stable maintenance of acidic nitrosation: by controlling the addition of alkali compounds, the pH in the reactor is maintained at a weak acidity, and the self-generated nitrite in the combined reactor forms a high concentration of nitrous acid, thereby ensuring the stable maintenance of the nitrosation function of the reactor. The technical solution provided by the present invention has the following advantages over the existing technical solutions: fast startup, high load, alkalinity saving, low equipment requirements, and a wide range of applications.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a high-efficiency acidic nitritation treatment process and device for ammonia-containing sewage. Background Art

[0002] The biological nitrification process of ammonia nitrogen is generally divided into two stages, namely ammonia oxidation and nitrite oxidation, which are completed by two types of chemoautotrophic microorganisms, as shown below:

[0003] (1) Ammonia oxidation process undertaken by Ammonia Oxidizing Bacteria (AOB):

[0004]

[0005] (2) Nitrite oxidation process undertaken by Nitrite Oxidizing Bacteria (NOB):

[0006]

[0007] Nitrifying bacteria are very sensitive to changes in pH. It is generally believed that the suitable pH range for nitrifying bacteria is 7.0-8.0, and the optimal pH is 7.5-8.0; when the pH is less than 6.5, the nitrification reaction rate decreases significantly; when the pH is less than 6.0, the nitrification rate is close to zero.

[0008] The microbial nitrification process (especially the ammonia oxidation reaction) is an acid-producing process. Each gram of ammonia nitrogen oxidized into nitrate nitrogen consumes 7.14g of alkalinity, of which the consumption is mainly in the ammonia oxidation process. Therefore, when the alkalinity in the sewage is insufficient, the nitrification reaction causes the pH value in the mixed solution to drop below 7.0, thereby reducing or inhibiting the nitrification rate. Therefore, in the nitrification treatment process of anaerobic digestion sludge, mid- and late-stage landfill leachate, source-separated urine, and some high-ammonia nitrogen industrial wastewater (such as silane tower wastewater in the photovoltaic industry) (even including urban sewage after enhanced pretreatment with the addition of iron salts), in order to maintain an appropriate pH in the nitrification system, it is often necessary to supplement a large amount of alkalinity, which comes at a high economic cost.

[0009] Control the nitrification reaction to only proceed to NO2 - -N stage, that is, to achieve a large amount of NO2 - -N accumulation is nitrification (also known as short-range nitrification) technology. Efficient and stable nitrification is one of the core links of new biological denitrification technologies such as anaerobic ammonium oxidation (ANAMMOX), that is, ANAMMOX relies on the nitrification reaction to NO2 --N provision. The nitritation process is essentially a comprehensive process of AOB enrichment and NOB elimination. Generally speaking, the strategy of inhibiting NOB activity and achieving nitritation is based on three principles: (1) the kinetic differences between AOB and NOB, (2) the resilience of AOB and NOB to pressure screening, and (3) the competition for nitrite by other microorganisms (such as ANAMMOX bacteria, denitrifying bacteria, etc.). How to achieve a stable and efficient nitritation process in a weakly acidic environment is still a blank. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to provide a high-efficiency acidic nitritation treatment process and device for ammonia-containing wastewater, so as to solve the problems of large alkalinity consumption in the nitrification treatment process of high-ammonia-containing wastewater and low nitritation load under weakly acidic conditions (pH value of 4-6).

[0011] In order to solve the above technical problems, the technical solution of the present invention is:

[0012] One of the purposes of the present invention is to provide a high-efficiency acidic nitritation treatment process for ammonia-containing wastewater.

[0013] The high-efficiency acidic nitritation treatment process for ammonia-containing wastewater of the present invention comprises:

[0014] (1) Acidic nitrification treatment: Ammonia-containing wastewater is continuously introduced into a continuous flow reactor inoculated with aerobic granular sludge to carry out microbial nitrification reaction. The pH is adjusted by adding alkaline compounds to achieve acidic nitrification treatment process;

[0015] (2) Rapid realization of acidic nitrosation:

[0016] (2-1) In situ exogenous nitrite inhibition: stop aeration and the introduction of ammonia-containing wastewater, add nitrite and a pH regulator to the reactor, adjust the pH in the reactor and maintain it for a certain period of time, then resume aeration and the introduction of ammonia-containing wastewater to maintain the pH in the reactor at a weakly acidic level, thereby achieving rapid accumulation of nitrite nitrogen in the reactor;

[0017] (2-2) Exogenous nitrite inhibition: Periodically remove part of the aerobic granular sludge from the reactor and soak it in a solution containing high concentration of nitrite for a certain period of time. Then, the soaked aerobic granular sludge is returned to the reactor to achieve the accumulation of nitrite in the effluent water.

[0018] (3) Stable maintenance of acidic nitrosation (inhibition of spontaneous nitrite): By continuously controlling the addition of alkaline compounds, the pH in the reactor is maintained at a weakly acidic level, thereby achieving stable maintenance of the accumulation of nitrite nitrogen in the discharged water.

[0019] In a preferred embodiment of the present invention:

[0020] In step (1):

[0021] The dissolved oxygen concentration under the aeration state is not less than 1 mg / L; and / or,

[0022] The particle size of the aerobic granular sludge is 0.2-0.8 mm; and / or,

[0023] The sludge concentration after the aerobic granular sludge is inoculated is 2-5 gVSS / L, and / or the sludge volume index SVI3=SVI 30 20-45 mL / g; and / or,

[0024] The ammonia nitrogen concentration of the ammonia-containing wastewater is not less than 50 mg / L; and / or,

[0025] The molar ratio of alkalinity to ammonia nitrogen in the ammonia-containing wastewater is (0.1-1):1, based on alkalinity as CaCO3; and / or

[0026] The alkaline compound is at least one of sodium bicarbonate and sodium carbonate; and / or,

[0027] The pH is 4-6.

[0028] In a preferred embodiment of the present invention:

[0029] In step (2-1):

[0030] The aeration and water inlet stop time is 0.5-2h; and / or,

[0031] The concentration of sodium nitrite after being added to the ammonia-containing wastewater is 150-250 mg / L; and / or,

[0032] The pH regulator is an iron salt (such as ferric chloride) and / or a waste acid (such as waste hydrochloric acid, waste sulfuric acid); and / or,

[0033] The pH in the reactor is adjusted to 2-4; and / or,

[0034] After the pH in the reactor is adjusted, the nitrite nitrogen concentration in the reactor is 30-50 mg / L; and / or,

[0035] The pH in the reactor is maintained at 4-6.

[0036] In a preferred embodiment of the present invention:

[0037] In step (2-2):

[0038] The periodic interval is 1 to 3 days; and / or,

[0039] The part of aerobic granular sludge is 1 / 3 to 1 / 10 of the total amount of aerobic granular sludge; and / or,

[0040] The concentration of the high-concentration nitrous acid solution is ≥50 mg / L; and / or,

[0041] The soaking time is 2-4 hours.

[0042] In a preferred embodiment of the present invention:

[0043] In step (3):

[0044] Before adjusting the amount of the alkaline compound added, ensure that the nitrite accumulation rate in step (2) is not less than 80%; and / or,

[0045] The alkaline compound is at least one of sodium bicarbonate and sodium carbonate; and / or,

[0046] The pH in the reactor is maintained at 4-6; and / or,

[0047] The FNA concentration in the discharged water was >1 mg / L.

[0048] The following solutions can be adopted:

[0049] (a) Inoculation: Aerobic granular sludge (particle size 0.2-0.8 mm) was inoculated into the continuous flow reactor to a sludge concentration (MLVSS) of 2-5 gVSS / L.

[0050] (b) Influent: The concentration of ammonia nitrogen (including ammonia nitrogen converted from organic nitrogen) in ammonia-containing wastewater shall generally not be less than 50 mg / L, and the molar ratio of alkalinity (measured as CaCO3) to ammonia nitrogen in ammonia-containing wastewater shall not be higher than 1;

[0051] (3) Acidic nitrification: The reactor is continuously fed with water. According to the acid production of the microbial nitrification reaction, the amount of alkalinity (sodium bicarbonate or sodium carbonate) added to the reactor is controlled to keep the pH in the range of 4-6, thus achieving stable and efficient acidic nitrification function.

[0052] (4) Rapid nitrosation:

[0053] Mode 1, in situ exogenous FNA inhibition: the reactor stops aeration and water inflow for 0.5-2 hours, during which time 30-50 mg / L of nitrite nitrogen is directly added to the reactor. At the same time, iron salts or waste acid are added to reduce the pH in the reactor to 2-4, creating a free nitrous acid (FNA) concentration in the reactor of not less than 50 mg / L; then, the reactor resumes normal aeration and water inflow, and continues to operate under weakly acidic conditions (pH 4-6), taking advantage of the fact that AOB activity recovers faster than NOB to quickly achieve nitrite accumulation.

[0054] Mode 2, ectopic exogenous FNA inhibition: The reactor maintains normal operation, and regularly (every 1 to 3 days) a certain proportion (1 / 3 to 1 / 10) of the sludge is taken out from the reactor and placed in a solution containing high concentration (not less than 50 mg / L) of FNA for 2-4 hours. The sludge is then returned to the reactor, and the cycle is repeated (the cycle frequency, the proportion of sludge taken out, the inhibition time, etc. can be adjusted appropriately according to the accumulation of nitrite). As the reactor continues to operate, nitrite gradually accumulates in the effluent.

[0055] (5) Stable maintenance of nitrite formation (i.e., inhibition of self-generated FNA): Based on the success of (4), the amount of alkalinity (sodium bicarbonate or sodium carbonate) added to the reactor is continuously controlled to maintain the pH in the range of 4-6. The nitrite nitrogen produced by AOB in the reactor is used to form a continuously high level of FNA (>1 mg / L) to effectively inhibit NOB.

[0056] A second object of the present invention is to provide a device for the efficient acidic nitritation treatment process of ammonia-containing wastewater as described in one of the objects of the present invention.

[0057] The device of the present invention comprises a water inlet bucket, a water inlet pump and an air stripping internal circulation reactor connected in sequence;

[0058] The gas lift internal circulation reactor includes an outer sleeve and an inner sleeve. The outer sleeve is higher than the inner sleeve. A water outlet window is provided on one side of the outer sleeve at a position higher than the inner sleeve. The water outlet end of the water inlet pump is connected to the inner sleeve. An aeration unit is provided in the inner sleeve.

[0059] In a preferred embodiment of the present invention:

[0060] A sedimentation area is connected between the side of the outer sleeve where the water outlet window is opened and the inner sleeve, and the bottom of the sedimentation area is lower than the top of the inner sleeve; and / or,

[0061] The aeration unit includes an oxygenating pump and an aeration sand head connected in sequence, and the aeration sand head extends into the inner sleeve; preferably, a gas flow meter is installed on the pipeline connecting the oxygenating pump and the aeration sand head.

[0062] In a preferred embodiment of the present invention:

[0063] The device is provided with an automatic control unit, which comprises a data acquisition module, a data processing module and a control module which are connected in sequence.

[0064] In a preferred embodiment of the present invention:

[0065] The data acquisition module is electrically connected to a DO (dissolved oxygen) probe and a pH probe respectively, and the DO probe and the pH probe extend into the inner sleeve.

[0066] In a preferred embodiment of the present invention:

[0067] The control module is electrically connected to the water inlet pump and the oxygenation pump respectively.

[0068] The present invention provides a method for the efficient acidic nitrosation treatment of ammonia-containing wastewater based on aerobic granular sludge, including the steps of aerobic granular sludge inoculation, rapid realization of acidic nitrosation function and stable maintenance. It can solve the problems of large alkalinity consumption in the nitrification treatment of high-ammonia-containing wastewater and low nitrosation load under weak acidic conditions (pH 4-6); at the same time, weak acidic conditions can promote the secretion of microbial extracellular polymers (EPS) and enhance the long-term stability of aerobic granular sludge. Based on the ammonia-containing wastewater treated by this method, the system nitrosation load reaches 0.3-1.5 kg N·m under pH 4-6. -3 ·d -1 Compared with the existing technical solutions, the technical solution provided by the present invention has the following advantages: fast start-up, high load, alkalinity saving, low equipment requirements, wide application range, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 Schematic diagram of the structure of the high-efficiency acidic nitritation treatment device for ammonia-containing wastewater of Example 1;

[0070] In the figure, 1-water inlet bucket, 2-water inlet pump, 3-oxygenation pump, 4-gas flow meter, 5-aeration sand head, 6-gas stripping internal circulation reactor, 6.1-inner sleeve, 6.2-sedimentation area, 6.3-water outlet window, 7-DO / pH control system, 8-DO probe, 9-pH probe;

[0071] Figure 2 This is the operating effect diagram of Example 2;

[0072] Figure 3 This is the microscopic morphology of aerobic granular sludge on the first day of Example 2;

[0073] Figure 4 This is the microscopic morphology of aerobic granular sludge on the 55th day of Example 2;

[0074] Figure 5 This is a graph showing particle size changes of aerobic granular sludge in Example 2;

[0075] Figure 6 This is a graph showing changes in EPS content in aerobic granular sludge in Example 2. DETAILED DESCRIPTION

[0076] The following is a further description of specific embodiments of the present invention in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is intended to facilitate understanding of the present invention and does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0077] The raw materials used in the embodiments of the present invention are all commercially available products.

[0078] Example 1

[0079] A highly efficient acidic nitrification treatment device for ammonia-containing wastewater, the structure of which is as follows: Figure 1 As shown, it includes a water inlet bucket 1, a water inlet pump 2 and an air stripping internal circulation reactor 6 connected in sequence; the air stripping internal circulation reactor 6 includes an outer sleeve and an inner sleeve 6.1, the outer sleeve is higher than the inner sleeve 6.1, a water outlet window 6.3 is opened on one side of the outer sleeve at a position higher than the inner sleeve, the water outlet end of the water inlet pump 2 is connected to the inner sleeve 6.1, and an aeration unit is provided in the inner sleeve 6.1; a sedimentation area 6.2 is connected between the side of the outer sleeve with the water outlet window 6.3 and the inner sleeve 6.1, and the bottom of the sedimentation area 6.2 is lower than the top of the inner sleeve 6.1; The unit includes an oxygenation pump 3 and an aeration sand head 5 connected in sequence, and the aeration sand head 5 extends into the inner sleeve 6.1; a gas flowmeter 4 is installed on the pipeline connecting the oxygenation pump 3 and the aeration sand head 5; the device of the present invention is provided with an automated control unit: a DO / pH control system 7, including a data acquisition module, a data processing module and a control module connected in sequence; the data acquisition module is electrically connected to a DO probe 8 and a pH probe 9, respectively, and the DO probe 8 and the pH probe 9 extend into the inner sleeve 6.1; the control module is electrically connected to the water inlet pump 2 and the oxygenation pump 3, respectively.

[0080] The device's specifications include an effective height of 20 cm and an effective volume of 1 L. Its design features approximately equal cross-sectional areas in the upflow region (within inner sleeve 6.1) and the downflow region (between outer sleeve and inner sleeve 6.1), maintaining a ratio of approximately 1:1 and ensuring uniform fluid distribution. Furthermore, a settling zone 6.2 is specifically designed within the airlift internal circulation reactor 6 to achieve solid-liquid separation through the excellent settling properties of the granular sludge. An aeration sand head 5 is installed at the bottom of the upflow region. This head is connected to a gas flowmeter 4 and an oxygenation pump 3, providing a stable power and energy supply for oxygen and sludge-water mixing within the reactor. Aeration volume is adjusted based on the reactor's actual operating conditions using a precise gas flowmeter. The airlift internal circulation reactor 6 is inoculated with mature aerobic granular sludge. After inoculation, the reactor sludge concentration (MLVSS) is 4.2 gVSS / L, the sludge settling ratio (SV3 = SV30) is approximately 30%, and the sludge volume index (SVI3 = SVI) is approximately 30%. 30The temperature in the reactor was controlled at 25°C, the hydraulic retention time (HRT) was maintained at 2.5 h, and the aeration rate was maintained at 400 ml / min.

[0081] Example 2

[0082] The ammonia-containing wastewater high-efficiency acidic nitritation treatment device of Example 1 was used to treat artificially prepared simulated urban sewage. The specific water quality was as follows (per liter): NH4 + -N is NH4Cl, 0.05g K2HPO4, 0.03g K2HPO4, 0.01gCaCl2·2H2O, 0.02g MgSO4·7H2O and 1ml trace elements; during operation, the pH in the reactor is maintained at 4-6 by controlling the amount of NaHCO3 added to the influent.

[0083] Trace element composition (per liter): 15g EDTA, 0.43g ZnSO4·7H2O, 0.24g CoCl2·6H2O, 1.0g MnCl2·4H2O, 0.25g CuSO4·5H2O, 0.22g (NH4)6Mo7O 24 ·4H2O, 0.20g NiCl2·6H2O, 0.09gHNaSeO3, 0.014g H3BO3, 0.054g Na2WO4·2H2O.

[0084] like Figure 2 The results are shown in the figure. During the whole experiment, the ammonia nitrogen concentration in the influent was maintained at 150 mg / L, and the pH in the reactor was maintained in the range of 4.4-5.3. During the 1-27 days, it was the acidic nitrification operation stage, and the ammonia nitrogen removal load was 0.34-0.65 kg / (m 3 Around day 28, the effluent was primarily composed of nitrate (32-68 mg / L), with little accumulation of nitrite. On day 28, the reactor was dehydrated and aerated, and 200 mg / L of ferric chloride and 200 mg / L of sodium nitrite were added. Mixing was continued for 0.5 h, during which the pH in the reactor dropped to 3.5±0.3. Aeration and water inflow were then resumed. With the inflow of influent, the pH gradually increased, and significant nitrite accumulation was observed in the effluent. During subsequent operation, approximately one-quarter of the granular sludge in the reactor was removed every three days and placed in a solution containing 50-90 mg / L of FNA (pH 3.5-4, nitrite concentration 30-50 mg / L) for two hours. The granular sludge was then returned to the reactor and normal operation was maintained. The amount of sodium bicarbonate added to the influent was continuously adjusted to maintain a pH of 4-6 in the reactor. After the 30th day, the nitrification rate and nitrification load of the reactor were maintained at 90% and 0.5 kg / (m 3d) or above (during which the FNA concentration in the reactor is maintained at 1.1-9.6 mg / L), that is, continuous and effective inhibition of NOB is achieved.

[0085] Depend on Figure 3 and Figure 4 From the microscopic morphology of the aerobic granular sludge, it can be found that after being treated by the method of the present invention, the microscopic shape of the aerobic granular sludge is more regular and the structure is more compact. Figure 5 From the particle size change diagram of aerobic granular sludge, it can be seen that the average particle size of aerobic granular sludge increased from 356μm on the first day to 440μm on the 55th day.

[0086] The EPS content of aerobic granular sludge was tested according to the existing technology "Interactions between nanoscale zero valent iron and extracellular polymeric substances of anaerobic sludge". The specific results are as follows Figure 6 As shown in the data, the EPS content of the aerobic granular sludge increased from 138±12 mg / gVSS on day 1 to 221±18 mg / gVSS on day 30, and finally to 324±8 mg / gVSS on day 55. This indicates that the method of the present invention can promote the secretion of extracellular polymers of microorganisms and enhance the long-term stability of aerobic granular sludge.

[0087] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. It is apparent to those skilled in the art that various changes, modifications, substitutions, and variations to these embodiments may be made without departing from the principles and spirit of the present invention, and these changes and modifications still fall within the scope of protection of the present invention.

Claims

1. A high-efficiency acidic nitritation process for treating ammonia-containing wastewater, the process comprising: (1) Acidic nitrification treatment: Under aeration, ammonia-containing wastewater is continuously introduced into a continuous flow reactor inoculated with aerobic granular sludge to carry out microbial nitrification reaction. The pH is adjusted by adding alkaline compounds to achieve acidic nitrification treatment process; (2) Rapid realization of acidic nitrosation: (2-1) Stop aeration and the introduction of ammonia-containing wastewater, add nitrite and a pH regulator to the reactor, adjust the pH in the reactor, and then resume aeration and the introduction of ammonia-containing wastewater to maintain the pH in the reactor at a weakly acidic level, thereby achieving rapid accumulation of nitrite nitrogen in the reactor; (2-2) Periodically remove part of the aerobic granular sludge from the reactor, soak it in a high-concentration nitrite solution, and then return the soaked aerobic granular sludge to the reactor to achieve the accumulation of nitrite in the discharged water; (3) Stable maintenance of acidic nitrite: Continuously control the addition of alkaline compounds to maintain the pH in the reactor at a weak acidic level, thereby achieving stable maintenance of nitrite in the discharged water; In step (1): The pH is 4-6; In step (2-1): The aeration and water inlet stop time is 0.5-2h; The concentration of nitrite after adding to ammonia-containing wastewater is 150-250 mg / L; The pH in the regulating reactor is 2-4; After the pH in the reactor is adjusted, the nitrite nitrogen concentration in the reactor is 30-50 mg / L; Maintaining the pH in the reactor at 4-6; In step (3): The pH in the reactor was maintained at 4-6.

2. The process according to claim 1, characterized in that: In step (1): The dissolved oxygen concentration in the aerated state is not less than 1 mg / L; and / or, The particle size of the aerobic granular sludge is 0.2-0.8 mm; and / or, The sludge concentration after the aerobic granular sludge is inoculated is 2-5 gVSS / L, and / or the sludge volume index SVI3=SVI 30 20-45 mL / g; and / or, The ammonia nitrogen concentration of the ammonia-containing wastewater is not less than 50 mg / L; and / or, The molar ratio of alkalinity to ammonia nitrogen in the ammonia-containing wastewater is (0.1-1):1, based on alkalinity as CaCO3; and / or The alkaline compound is at least one of bicarbonate and carbonate.

3. The process according to claim 1, characterized in that: In step (2-1): The pH regulator is iron salt and / or waste acid.

4. The process according to claim 1, wherein: In step (2-2): The periodic interval is 1 to 3 days; and / or, The part of aerobic granular sludge is 1 / 3 to 1 / 10 of the total amount of aerobic granular sludge; and / or, The concentration of the high-concentration nitrous acid solution is ≥50 mg / L; and / or, The soaking time is 2-4 hours.

5. The process according to claim 1, characterized in that: In step (3): Before adding the alkaline compound, ensure that the nitrite accumulation rate in step (2) is not less than 80%; and / or, The alkaline compound is at least one of sodium bicarbonate and sodium carbonate; and / or, The concentration of nitrite in the effluent water is >1 mg / L.

6. A device for treating ammonia-containing wastewater using the high-efficiency acidic nitritation process according to any one of claims 1 to 5, comprising a water inlet bucket, a water inlet pump, and an air stripping internal circulation reactor connected in sequence; The gas lift internal circulation reactor includes an outer sleeve and an inner sleeve. The outer sleeve is higher than the inner sleeve. A water outlet window is provided on one side of the outer sleeve at a position higher than the inner sleeve. The water outlet end of the water inlet pump is connected to the inner sleeve. An aeration unit is provided in the inner sleeve.

7. The device according to claim 6, characterized in that: A sedimentation area is connected between the side of the outer sleeve where the water outlet window is opened and the inner sleeve, and the bottom of the sedimentation area is lower than the top of the inner sleeve; and / or, The aeration unit comprises an oxygenating pump and an aeration sand head which are connected in sequence, and the aeration sand head extends into the inner sleeve; a gas flow meter is installed on the pipeline connecting the oxygenating pump and the aeration sand head.

8. The device according to claim 6 or 7, characterized in that: The device is provided with an automatic control unit, which comprises a data acquisition module, a data processing module and a control module which are connected in sequence.

9. The device according to claim 8, characterized in that: The data acquisition module is electrically connected to the DO probe and the pH probe respectively, and the DO probe and the pH probe extend into the inner sleeve.

10. The device according to claim 8, characterized in that: The control module is electrically connected to the water inlet pump and the oxygenation pump respectively.

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