System and method for realizing stable operation of short-cut nitrification process of urban sewage by light regulation

Abstract

The present application relates to a kind of light regulation to realize the stable operation of urban sewage short path nitrification process system and method, the present application is characterized in that short path nitrification reactor is operated with low sludge concentration, natural light or light emitting diode is used to the reactor with a certain intensity of light, and according to the actual operation situation adjustment light intensity, selectively inhibit nitrite oxidizing bacteria proliferation, do not affect ammonia-oxidizing bacteria enrichment growth, to realize the accumulation of nitrite, obtain long-term highly stable urban sewage short path nitrification process.In addition, the light involved in the present application can be directly derived from solar energy, and the reaction process does not need additional aeration, in line with the requirements of green environmental protection, energy saving and emission reduction of urban sewage treatment in China, has strong guiding significance to realize the stable short path nitrification process of urban sewage.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and in particular to a system and method for achieving stable operation of short-cut nitrification processes for urban wastewater through light-controlled regulation. Background Technology

[0002] Urban wastewater in my country is typically characterized by a low carbon-to-nitrogen ratio, and achieving total nitrogen discharge standards often relies on external carbon source addition, resulting in high operating costs and large carbon emissions. Novel short-process nitrogen removal technologies, such as anaerobic ammonium oxidation (ANAO), can significantly reduce aeration energy consumption and carbon source consumption, as well as sludge production, providing an important pathway for synergistic efficiency improvement in urban wastewater treatment by reducing pollution and carbon emissions. However, stable operation of short-cut nitrification remains a technical bottleneck for the application of mainstream urban wastewater ANAO projects.

[0003] Short-cut nitrification refers to the process of reducing ammonia nitrogen (NH4) to nitrogen. + The oxidation of nitrite (NO2) is controlled within the nitrite nitrogen (NO2) range. - To prevent further conversion into nitrate nitrogen (NO3) - This provides a key substrate for anaerobic ammonia oxidizing bacteria. Ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) are two core competing microorganisms involved in controlling short-cut nitrification. The stable operation of short-cut nitrification hinges on achieving AOB enrichment and NOB elimination. Currently, methods to inhibit NOB metabolism and growth can be categorized into three types: 1) optimizing operating strategies, including controlling temperature, dissolved oxygen, and sludge age; 2) adding inhibitory substances, including free ammonia, free nitrite, sulfides, hydroxylamine, and ultrasound; 3) bioaugmentation and selective washing, including inoculation with ammonia oxidizing bacteria or anaerobic ammonia oxidizing bacteria. Notably, hydroxylamine is a key intermediate product in the oxidation of ammonia to nitrite. Adding a small amount of hydroxylamine can promote the activity of ammonia monooxygenase and hydroxylamine oxidase, and has been used to maintain the stability of low-substrate municipal wastewater short-cut nitrification processes. However, hydroxylamine's inhibition of NOB is reversible. To maintain long-term NOB inhibition, continuous addition of hydroxylamine is required, which not only increases the operating costs of wastewater treatment plants but also introduces significant irreversibility into the nitrification and ascites processes, potentially leading to toxin accumulation and secondary pollution. In summary, although various selective NOB inhibition strategies have been proven feasible for achieving short-cut nitrification, NOB adaptability issues result in poor long-term NOB inhibition, especially in urban wastewater systems with low ammonia nitrogen concentrations, where the process performance stability of short-cut nitrification is poor. Therefore, there is an urgent need to develop new and effective strategies to achieve AOB enrichment and NOB inhibition to stably maintain short-cut nitrification in urban wastewater.

[0004] Light energy is a form of electromagnetic radiation composed of photons emitted by hot objects. Most of the energy needed by humans comes directly or indirectly from the sun, and solar energy, as the most widely available renewable energy source, has been widely used as an auxiliary process in water treatment. Numerous studies have shown that both AOB (Aging By-products) and NOB (Natural Oxygen Absorbers) are photosensitized, with NOB being more sensitive to light than AOB; light irradiation can selectively inhibit NOB activity. Furthermore, light-controlled short-cut nitrification strategies do not involve the addition of chemical inhibitors, reducing process complexity and exhibiting high efficiency, green practices, energy conservation, and low carbon emissions. Therefore, light irradiation provides a new approach to achieving short-cut nitrification, helping to improve the stability of short-cut nitrification in urban wastewater and holding significant importance for the development and application of short-cut nitrification processes.

[0005] Compared to patent CN202210727287.2, which provides a process for purifying high-ammonia nitrogen wastewater using microalgae coupled with short-cut nitrification activated sludge, this patent involves controlling the duration and intensity of light exposure to create an alternating aerobic-anoxic environment in the reactor. Under optimal operating conditions, the system can remove nitrogen and phosphorus without aeration. Comparing patent CN201910264789.4, which provides a method and apparatus for rapidly achieving stable short-cut nitrification of urban domestic sewage using bioaugmentation technology combined with real-time control, this patent describes a reactor for treating high-ammonia nitrogen wastewater. In the first sequencing batch reactor, short-cut nitrification is achieved through free ammonia (FA) and real-time control. Short-cut nitrified sludge is discharged and stored each cycle. In the second sequencing batch reactor, organic matter and nitrogen are removed. In the anoxic zone, short-cut digested sludge is added for bioaugmentation, and prolonged anoxic conditions combined with real-time control rapidly enrich AOB in the reactor, inhibiting NOB and achieving rapid, stable short-cut nitrification for deep denitrification. However, the existing patents have complex process setups, require additional aeration, and have high energy consumption. Summary of the Invention

[0006] The purpose of this invention is to address the challenge of maintaining long-term stability in short-cut nitrification of urban wastewater by providing a system and method for achieving stable operation of the short-cut nitrification process through light regulation. This system is applicable to urban wastewater treatment. The key feature of this invention is operating the short-cut nitrification reactor with low sludge concentration. A certain intensity of light is applied to the reactor using natural light or LEDs, and the light intensity is adjusted according to actual operating conditions. This selectively inhibits the proliferation of nitrite-oxidizing bacteria without affecting the enrichment and growth of ammonia-oxidizing bacteria, thereby achieving nitrite accumulation and obtaining a long-term, highly stable short-cut nitrification process for urban wastewater.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] A system for achieving stable operation of a short-cut nitrification process in urban wastewater through light-controlled processes includes an influent tank, a sequencing batch reactor (SBR), a light source, and an effluent tank.

[0009] One end of the sequencing batch reactor is connected to the inlet tank via a pipe, and the other end of the sequencing batch reactor is connected to the outlet tank via a pipe. A light source is installed inside the sequencing batch reactor.

[0010] The inlet tank is used to feed urban sewage into the sequencing batch reactor (SBR), which is used for short-cut nitrification of urban sewage. The light source is used to provide illumination to the SBR, and the stability of the short-cut nitrification process of urban sewage is maintained by a certain intensity of light.

[0011] Furthermore, there are no special requirements regarding the relative positions of the light source and the sequencing batch reactor.

[0012] Furthermore, the system also includes an online monitoring device and a display, with one end of the online monitoring device connected to the sequencing batch reactor and the other end connected to the display.

[0013] Furthermore, the online monitoring device is equipped with a display interface, and the display is connected to the online monitoring device through the display interface.

[0014] Furthermore, the sequencing batch reactor is equipped with a pH meter and a dissolved oxygen (DO) meter. The bottom ends of the pH meter and the dissolved oxygen meter are inserted into the sequencing batch reactor, and the top ends of the pH meter and the dissolved oxygen meter are connected to an online monitoring device for monitoring the pH and DO of the sequencing batch reactor.

[0015] Furthermore, the pH and dissolved oxygen detectors are equipped with temperature sensors at their probes. These temperature sensors are connected to online monitoring equipment and are used to synchronously monitor the temperature within the sequencing batch reactor. Additionally, the sequencing batch reactor is equipped with a stirrer to enhance mass transfer.

[0016] Furthermore, an inlet pump is installed on the pipeline connecting the sequencing batch reactor to the inlet tank, and the inlet pump is used to pump urban sewage from the inlet tank into the sequencing batch reactor.

[0017] Furthermore, an outlet pump is installed on the pipeline connecting the sequencing batch reactor to the outlet tank, and the outlet pump is used to pump the outlet water of the sequencing batch reactor into the outlet tank.

[0018] Furthermore, this invention also provides a method for achieving stable operation of a short-cut nitrification process for urban wastewater using light-controlled processes, employing the aforementioned system, with the specific steps as follows:

[0019] S1. Inoculate sludge into the sequencing batch reactor;

[0020] S2. Low-concentration urban sewage is introduced into the sequencing batch reactor through the inlet tank, and the agitator is turned on to stir.

[0021] S3. Turn on the light source to irradiate the sequencing batch reactor and carry out the aerobic reaction;

[0022] S4. Real-time monitoring of pH and DO concentration in the sequencing batch reactor is achieved by linking online monitoring equipment with pH and dissolved oxygen detectors.

[0023] S5. Take samples at regular intervals and measure the concentrations of ammonia nitrogen, nitrite and nitrate in the sequencing batch reactor. After all the ammonia nitrogen in the urban sewage is converted into nitrite and precipitates, it enters the drainage stage.

[0024] S6. After the drainage is completed, pump municipal sewage into the sequencing batch reactor and repeat the above steps, running 1-2 cycles per day.

[0025] Furthermore, in step S1, the sludge concentration in the sequencing batch reactor during the reaction process is ≤800~1000mg MLSS / L, and the sludge contains ammonia-oxidizing bacteria and nitrite-oxidizing bacteria. Light irradiation makes the short-cut nitrification process more stable.

[0026] Furthermore, in step S2, the ammonia nitrogen concentration of the urban sewage is 20–70 mg / L.

[0027] Furthermore, in step S2, the stirring speed is 100-150 rpm; low-speed stirring makes the reaction more uniform. For industrial production, the speed can be determined based on the stirring radius and reactor size.

[0028] Furthermore, in step S3, the light intensity inside the sequencing batch reactor is 50–360 μW / cm². 2 The specific light intensity needs to be adjusted based on the sludge concentration and short-cut nitrification performance.

[0029] The temperature of the sequencing batch reactor is controlled at 25–30°C.

[0030] Furthermore, in step S3, the light source can directly utilize natural light or select a light-emitting diode to simulate natural light, wherein the form of the light-emitting diode is not limited.

[0031] Further, in step S5, the concentrations of ammonia nitrogen, nitrite and nitrate in the sequencing batch reactor are sampled and measured at regular intervals. After all the ammonia nitrogen in the urban sewage has been converted into nitrite, the stirrer and light source are turned off.

[0032] After the aerobic reaction is completed, stirring is stopped, and then the sedimentation stage begins. After the mud and water are separated, the effluent pump is turned on to discharge the wastewater treated by the sequencing batch reactor into the effluent tank.

[0033] Furthermore, the wastewater discharge ratio into the outlet tank is 70-90%.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] 1) This invention is based on a light-controlled short-cut nitrification process for urban wastewater, which can effectively enrich ammonia-oxidizing bacteria and selectively inhibit nitrite-oxidizing bacteria, thus solving the technical problem of stable operation of mainstream short-cut nitrification.

[0036] 2) This invention does not require aeration and operates the short-cut nitrification process for urban wastewater at low sludge concentrations, reducing sludge production and helping to further reduce operating energy consumption and greenhouse gas emissions.

[0037] 3) The light source materials used in this invention are widely available and inexpensive. In practical applications, natural light or light-emitting diodes can be used directly, and the illumination can be directly derived from solar energy, which has the characteristics of being green and environmentally friendly, reducing the complexity of process operation and energy consumption.

[0038] 4) The light source involved in this invention can be directly derived from solar energy, and the reaction process does not require additional aeration, which meets the requirements of green environmental protection, energy conservation and emission reduction in urban sewage treatment in my country, and has strong guiding significance for realizing stable short-cut nitrification process of urban sewage.

[0039] 5) This invention is simple to operate, requires no bio-enhancing or addition of inhibitory substances, and requires no additional aeration. It also operates a low-ammonia nitrogen short-cut nitrification process for urban wastewater at low sludge concentrations, reducing sludge production and further reducing operating energy consumption and greenhouse gas emissions.

[0040] Other features and advantages of the present invention will be described in detail in the Detailed Description of Embodiments section. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the system for achieving stable operation of short-cut nitrification process in urban wastewater by light regulation according to the present invention;

[0042] Figure 2 This is a schematic diagram of the system structure of the short-cut nitrification process for urban wastewater in Comparative Example 1 of the present invention;

[0043] Figure 3 This is a schematic diagram of the system for achieving stable operation of the short-cut nitrification process in urban wastewater using light control, as described in Embodiment 2 of the present invention.

[0044] Figure 4 This is a schematic diagram of the system for achieving stable operation of the short-cut nitrification process in urban wastewater using light control, as described in Embodiment 3 of the present invention.

[0045] Figure 5 The ammonia nitrogen (NH4) in the feed water of the first sequencing batch reactor in Comparative Example 1 of this invention + Concentration of ammonia nitrogen (NH4+) in effluent +-N), nitrite (NO2) — N), (NO3) - Graph showing the changes in nitrite concentration and nitrite accumulation rate (NAR) over time;

[0046] Figure 6 The ammonia nitrogen (NH4) in the feed water of the second sequencing batch reactor in Example 2 of this invention + Concentration of ammonia nitrogen (NH4+) in effluent + -N), nitrite (NO2) — N), (NO3) - Graph showing the changes in nitrite concentration and nitrite accumulation rate (NAR) over time;

[0047] Figure 7 The ammonia nitrogen (NH4) in the feed water of the third sequence batch reactor in Example 3 of this invention + Concentration of ammonia nitrogen (NH4+) in effluent + -N), nitrite (NO2) — N), (NO3) - The graph shows the changes in nitrite concentration and nitrite accumulation rate (NAR) over time.

[0048] Explanation of the attached figures: 1. Inlet tank; 2. Sequencing batch reactor; 3. Light source; 4. Outlet tank; 5. Online monitoring equipment; 6. Display; 7. Inlet pump; 8. Agitator; 9. pH meter; 10. Dissolved oxygen meter; 11. Outlet pump; 12. Water bath; 13. LED light strip; 2a. First sequencing batch reactor; 2b. Second sequencing batch reactor; 2c. Third sequencing batch reactor. Detailed Implementation

[0049] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0050] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0051] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0052] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0053] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0054] Example 1

[0055] See Figure 1 This embodiment provides a system for achieving stable operation of a short-cut nitrification process for urban wastewater through light-controlled operation, comprising an influent tank 1, a sequencing batch reactor 2, a light source 3, and an effluent tank 4.

[0056] One end of the sequencing batch reactor 2 is connected to the inlet tank 1 via a pipe, and the other end of the sequencing batch reactor 2 is connected to the outlet tank 4 via a pipe. A light source 3 is installed inside the sequencing batch reactor 2.

[0057] The inlet tank 1 is used to feed urban sewage into the sequencing batch reactor 2, which is used for short-cut nitrification of urban sewage. The light source 3 is used to provide illumination to the sequencing batch reactor 2, and the stability of the short-cut nitrification process of urban sewage is maintained by a certain intensity of light.

[0058] In this embodiment, the light source 3 is fixedly located at the middle of the outer side of the sequencing batch reactor 2.

[0059] In this embodiment, the sequencing batch reactor 2 is located in a water bath 12 and is heated by a water bath to maintain a constant temperature of 30°C.

[0060] In this embodiment, the system further includes an online monitoring device 5 and a display 6. One end of the online monitoring device 5 is connected to the sequencing batch reactor 2, and the other end of the online monitoring device 5 is connected to the display 6.

[0061] In this embodiment, the online monitoring device 5 is equipped with a display 6 interface, and the display 6 is connected to the online monitoring device 5 through the display 6 interface.

[0062] In this embodiment, the sequencing batch reactor 2 is equipped with a pH meter 9 and a dissolved oxygen (DO) meter 10. The bottom ends of the pH meter 9 and the dissolved oxygen meter 10 are inserted into the sequencing batch reactor 2, and the top ends of the pH meter 9 and the dissolved oxygen meter 10 are connected to an online monitoring device 5. The online monitoring device 5 is used to monitor the pH and DO of the sequencing batch reactor 2.

[0063] In this embodiment, temperature sensors are provided at the probes of the pH detector 9 and the dissolved oxygen detector 10. The temperature sensors are connected to the online monitoring device 5 and are used to synchronously monitor the temperature inside the sequencing batch reactor 2.

[0064] In this embodiment, the sequencing batch reactor 2 is equipped with a stirrer 8, which is a magnetic stirrer, and the stirrer 8 is used to enhance mass transfer.

[0065] In this embodiment, an inlet pump 7 is provided on the pipeline connecting the sequencing batch reactor 2 and the inlet tank 1. The inlet pump 7 is used to pump urban sewage from the inlet tank 1 into the sequencing batch reactor 2.

[0066] In this embodiment, an outlet pump 11 is provided on the pipeline connecting the sequencing batch reactor 2 and the outlet tank 4. The outlet pump 11 is used to pump the outlet water of the sequencing batch reactor 2 into the outlet tank 4.

[0067] Furthermore, this embodiment also provides a method for achieving stable operation of short-cut nitrification processes in urban wastewater through light regulation, the specific steps of which are as follows:

[0068] S1. Inoculate sludge into the sequencing batch reactor 2;

[0069] S2. Low-concentration urban sewage is introduced into the sequencing batch reactor 2 through the inlet tank 1, and the agitator 8 is turned on to stir.

[0070] S3. Turn on light source 3 to apply light to sequence batch reactor 2 to carry out aerobic reaction;

[0071] S4. The pH value and DO concentration in the sequencing batch reactor 2 are monitored in real time by linking the online monitoring device 5 with the pH detector 9 and the dissolved oxygen detector 10.

[0072] S5. Take samples at regular intervals and measure the concentrations of ammonia nitrogen, nitrite and nitrate in sequencing batch reactor 2. After all the ammonia nitrogen in the urban sewage is converted into nitrite and precipitates, it enters the drainage stage.

[0073] S6. After the drainage is completed, repeat the above steps and re-feed the urban sewage into the sequencing batch reactor 2, running 1-2 cycles per day.

[0074] In this embodiment, in step S1, the sludge concentration in the sequencing batch reactor 2 during the reaction process is ≤800~1000mgMLSS / L, and the sludge contains ammonia-oxidizing bacteria and nitrite-oxidizing bacteria.

[0075] In this embodiment, in step S2, the ammonia nitrogen concentration of the urban sewage is 20-70 mg / L.

[0076] In this embodiment, in step S2, the stirring speed is 100-150 rpm.

[0077] In this embodiment, in step S3, the light intensity inside the sequencing batch reactor 2 is 50–360 μW / cm². 2 The specific light intensity can be adjusted according to the operating conditions; the temperature of the sequencing batch reactor 2 is controlled at 25-30℃.

[0078] In this embodiment, in step S3, the light source 3 can directly utilize natural light or select a light-emitting diode to simulate natural light, wherein the form of the light-emitting diode is not limited.

[0079] In this embodiment, in step S5, the concentrations of ammonia nitrogen, nitrite and nitrate in the sequencing batch reactor 2 are sampled and measured at regular intervals. After all the ammonia nitrogen in the urban sewage is converted into nitrite, the stirrer 8 and the light source 3 are turned off.

[0080] After the aerobic reaction is completed, stirring is stopped, and then the sedimentation stage begins. After the mud and water are separated, the effluent pump 11 is turned on to discharge the wastewater treated by the sequencing batch reactor 2 into the effluent tank 4.

[0081] In this embodiment, the wastewater discharge ratio into the outlet tank 4 is 70-90%.

[0082] Example 2

[0083] See Figure 3 This embodiment provides a system for achieving stable operation of short-cut nitrification process of urban sewage through light control. Except that the second sequencing batch reactor 2b is equipped with a light-emitting diode light strip 13, the rest is the same as in embodiment 1.

[0084] Furthermore, this embodiment also provides a method for achieving stable operation of short-cut nitrification processes in urban wastewater through light regulation, the specific steps of which are as follows:

[0085] S1. Inoculate sludge into the second sequencing batch reactor 2b;

[0086] S2. The synthetic wastewater is fed into the second batch reactor 2b through the inlet tank 1;

[0087] S3. During operation, a water bath is used to maintain a constant temperature of 30±2℃ inside the second batch reactor 2b; and a magnetic stirrer is used for stirring at a speed of 100 rpm and a stirring radius of 15 mm.

[0088] S4. Turn on the LED light strip 13 to apply light to the second sequence batch reactor 2b to carry out the aerobic reaction;

[0089] S5. The pH value and DO concentration in the second sequencing batch reactor 2b are monitored in real time by linking the online monitoring device 5 with the pH detector 9 and the dissolved oxygen detector 10.

[0090] S6. After the aerobic reaction has run for 24 hours, turn off the magnetic stirrer and LED strip 3.

[0091] S7. Enter the sedimentation stage. After sedimentation for 30 minutes, turn on the effluent pump 12 to discharge the wastewater treated by the second batch reactor 2b into the effluent tank 4 with a discharge ratio of 90%.

[0092] S8. After drainage is completed, turn on the inlet pump 7 to pump synthetic wastewater into the second batch reactor 2b and repeat the above steps.

[0093] In this embodiment, in step S1, the effective volume of the sequencing batch reactor 2 is 2.5L, and the sludge concentration is controlled to be ≤500mg MLSS / L during the reaction of the second sequencing batch reactor 2b.

[0094] In this embodiment, in step S2, the specific water quality of the artificially synthesized wastewater is as follows: ammonia nitrogen concentration is 51.52±0.5mg / L, nitrite concentration is 3.15±0.5mg / L, nitrate concentration is 1.44±0.5mg / L, and there is no COD; the pH is controlled between 7.5 and 8.0.

[0095] In this embodiment, in step S4, the light intensity inside the second sequencing batch reactor 2b is 50 μW / cm². 2 In this embodiment, the sludge concentration is low and the short-range performance is relatively stable, and the light intensity setting is low and unchanged.

[0096] Example 3

[0097] See Figure 4This embodiment provides a system for achieving stable operation of short-cut nitrification process of urban sewage through light control. Except that the third batch reactor 2c is equipped with a light-emitting diode light strip 13, the rest is the same as in embodiment 1.

[0098] Furthermore, this embodiment also provides a method for achieving stable operation of a short-cut nitrification process for urban wastewater through light regulation, except that the light intensity in the third batch reactor 2c is 200 μW / cm². 2 The rest is the same as in Example 2.

[0099] Comparative Example 1

[0100] See Figure 2 This comparative example provides a system for a short-cut nitrification process for urban wastewater, which is the same as in Example 1 except that the first sequencing batch reactor 2a does not have a light source.

[0101] In addition, this embodiment also provides a method for short-cut nitrification of urban wastewater, which is the same as in embodiment 2 except that there is no light control in the first batch reactor 2a.

[0102] The test results are as follows Figures 5-7 As shown: In Comparative Example 1, the NAR of the first sequencing batch reactor 2a was relatively stable only in the first 20 days, reaching over 94.0%; after 20 days, the NAR showed a sharp decreasing trend; by 25 days, it had transformed into full nitrification.

[0103] In Example 2, the NAR of the second sequencing batch reactor 2b and in Example 3, the NAR of the third sequencing batch reactor 2c remained stable at a high level from 2 to 47 days, above 94.4% and 93.0% respectively, indicating good short-cut nitrification performance.

[0104] Therefore, the light intensity is 50 μW / cm 2 and 200μW / cm 2 Light regulation can maintain the stability of short-cut nitrification processes in urban wastewater over a long period of time.

[0105] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A system for achieving stable operation of short-cut nitrification process in urban wastewater through light-controlled operation, characterized in that, It includes an inlet tank (1), a sequencing batch reactor (2), a light source (3), and an outlet tank (4). One end of the sequencing batch reactor (2) is connected to the inlet tank (1) through a pipe, and the other end of the sequencing batch reactor (2) is connected to the outlet tank (4) through a pipe. The sequencing batch reactor (2) is equipped with a light source (3). The inlet tank (1) is used to feed urban sewage into the sequencing batch reactor (2), which is used for short-cut nitrification of urban sewage. The light source (3) is used to provide illumination to the sequencing batch reactor (2) and maintain the stability of the short-cut nitrification process of urban sewage through a certain intensity of light. During the reaction, sludge is inoculated into the sequencing batch reactor (2), and the sludge concentration is... 800~1000 mg MLSS / L, the sludge contains ammonia-oxidizing bacteria and nitrite-oxidizing bacteria; The intensity of the light source (3) applied to the sequencing batch reactor (2) is 50~360 μW / cm. 2 .

2. The system for achieving stable operation of short-cut nitrification process in urban wastewater by light regulation according to claim 1, characterized in that, The system also includes an online monitoring device (5) and a display (6), one end of which is connected to the sequencing batch reactor (2) and the other end of which is connected to the display (6).

3. The system for achieving stable operation of short-cut nitrification process in urban wastewater by light regulation according to claim 2, characterized in that, The sequencing batch reactor (2) is equipped with a pH detector (9) and a dissolved oxygen detector (10). The bottom ends of the pH detector (9) and the dissolved oxygen detector (10) are inserted into the sequencing batch reactor (2). The top ends of the pH detector (9) and the dissolved oxygen detector (10) are connected to an online monitoring device (5). The online monitoring device (5) is used to monitor the pH and DO of the sequencing batch reactor (2). Temperature sensors are provided at the probes of the pH detector (9) and dissolved oxygen detector (10). The temperature sensors are connected to the online monitoring device (5) and are used to synchronously monitor the temperature inside the sequencing batch reactor (2).

4. The system for achieving stable operation of short-cut nitrification process in urban wastewater by light regulation according to claim 1, characterized in that, The sequencing batch reactor (2) is equipped with a stirrer (8) for enhancing mass transfer.

5. The system for achieving stable operation of short-cut nitrification process in urban wastewater by light regulation according to claim 1, characterized in that, The pipeline connecting the sequencing batch reactor (2) to the inlet tank (1) is equipped with an inlet pump (7), which is used to pump urban sewage from the inlet tank (1) into the sequencing batch reactor (2). The pipeline connecting the sequencing batch reactor (2) to the outlet tank (4) is equipped with an outlet pump (11), which is used to pump the outlet water of the sequencing batch reactor (2) into the outlet tank (4).

6. A method for achieving stable operation of a short-cut nitrification process in urban wastewater through light regulation, characterized in that, The system described in any one of claims 1-5 is used, and the specific steps are as follows: S1. Inoculate sludge into the sequencing batch reactor (2); S2. Low-concentration urban sewage is introduced into the sequencing batch reactor (2) through the inlet tank (1), and the agitator (8) is turned on to stir. S3. Turn on the light source (3) to apply light to the sequencing batch reactor (2) to carry out the aerobic reaction; S4. The pH value and DO concentration in the sequencing batch reactor (2) are monitored in real time by linking the online monitoring device (5) with the pH detector (9) and the dissolved oxygen detector (10). S5. Take samples at regular intervals and measure the concentrations of ammonia nitrogen, nitrite and nitrate in the sequencing batch reactor (2). After all the ammonia nitrogen in the urban sewage is converted into nitrite, it will enter the drainage stage after precipitation. S6. After drainage is completed, repeat the above steps.

7. The method for achieving stable operation of a short-cut nitrification process in urban wastewater by light regulation according to claim 6, characterized in that, In step S2, the ammonia nitrogen concentration of the urban sewage is 20~70 mg / L.

8. The method for achieving stable operation of a short-cut nitrification process in urban wastewater by light regulation according to claim 6, characterized in that, In step S3, the temperature of the sequencing batch reactor (2) is controlled to be 25~30℃.

9. The method for achieving stable operation of a short-cut nitrification process in urban wastewater by light regulation according to claim 6, characterized in that, In step S5, the concentrations of ammonia nitrogen, nitrite and nitrate in the sequencing batch reactor (2) are sampled and measured at regular intervals. After all the ammonia nitrogen in the urban sewage is converted into nitrite, the stirrer (8) and the light source (3) are turned off. After the aerobic reaction is completed, stirring is stopped, and then the sedimentation stage begins. After the mud and water are separated, the effluent pump (11) is turned on to discharge the wastewater treated by the sequencing batch reactor (2) into the effluent tank (4). The discharge ratio of the wastewater into the effluent tank (4) is 70-90%.

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