High-activity short-cut nitrification process for rapid start-up and long-term stable operation

Abstract

The application discloses a high-activity short-cut nitrification fast-starting long-term stable operation process and relates to the technical field of sewage biological treatment, which comprises the following steps: inoculating sludge and performing anaerobic fermentation pretreatment, combining with rapid sludge discharge and manual removal of expanded sludge and sludge foam; controlling sludge age in days, performing sludge repropagation, enriching ammonia-oxidizing bacteria, inhibiting and eluting nitrite-oxidizing bacteria; long-term operation under the condition of no sludge discharge, maintaining the abundance and activity of ammonia-oxidizing bacteria, and simultaneously controlling the abundance of nitrite-oxidizing bacteria; controlling the proliferation of nitrite-oxidizing bacteria by using the predation of protozoa and metazoan, and controlling the nitrite accumulation rate in the reactor; monitoring the concentrations of dissolved oxygen, pH value, ammonia nitrogen, nitrite nitrogen and nitrate nitrogen in the reactor in real time, adjusting the ammonia nitrogen load and free ammonia concentration of influent, and adopting intermittent aeration or microporous aeration to adjust the distribution of dissolved oxygen and optimize the operation conditions of the short-cut nitrification reactor. The application is simple, economical and effective.

Description

Technical Field

[0001] This invention relates to the field of wastewater biological treatment technology, and in particular to a highly active short-cut nitrification process that allows for rapid start-up and long-term stable operation. Background Technology

[0002] With the continuous growth of the population and the improvement of people's living standards, the per capita discharge of domestic sewage continues to increase. Urban sewage generally lacks carbon sources and has high nitrogen and phosphorus content. From the perspective of biological treatment, conventional biological denitrification processes use aerobic bacteria to remove NH4+. + -N is oxidized to NO2 - -N and NO3 - -N, and then heterotrophic denitrifying bacteria use carbon sources as electron donors to reduce nitrate and nitrite nitrogen into nitrogen gas. During this process, a large amount of aeration and internal reflux energy consumption are required, and a large amount of carbon sources are also consumed, resulting in high treatment costs.

[0003] Compared to conventional biological methods, the PN / A process, which combines short-cut nitrification and anaerobic ammonium oxidation, eliminates the need for aeration and denitrification processes, thus reducing sludge volume. However, one of the two major bottlenecks in the actual operation of the PN / A process is NO2. - The stable source of nitrite (NOB) lies in the fact that ammonia-oxidizing bacteria (AOB) and anaerobic ammonia-oxidizing bacteria (AMX) in the process are environmentally sensitive and difficult to inhibit nitrite-oxidizing bacteria (NOB) during operation. To achieve stable operation, precise control of multiple parameters such as dissolved oxygen (DO) and sludge age is necessary. Furthermore, the influent may contain substances toxic to microorganisms. Secondly, there is a lack of carbon separation methods before the PN / A process. In actual operation, washing away nitrite-oxidizing bacteria and enriching ammonia-oxidizing bacteria to achieve stable nitrite accumulation is a research direction for many scholars, and many effective methods have been developed. Controlling temperature to widen the growth rate difference between ammonia-oxidizing and nitrite-oxidizing bacteria, while simultaneously controlling the sludge age... The nitrite-oxidizing bacteria are washed out by controlling the sludge age between the growth cycles of ammonia-oxidizing and nitrite-oxidizing bacteria. Dissolved oxygen (DO) concentration: Due to the different oxygen saturation coefficients of ammonia-oxidizing and nitrite-oxidizing bacteria, DO is controlled below 0.5 mg / L, while simultaneously controlling the sludge age between the growth cycles of ammonia-oxidizing and nitrite-oxidizing bacteria to achieve nitrite-oxidizing bacteria washing out. Free ammonia (FN) and free nitrite nitrogen (FNA) pretreatment: The differential inhibition of ammonia-oxidizing and nitrite-oxidizing bacteria by FN and FNA achieves short-cut nitrification. Full-load aeration combined with low sludge age achieves nitrite-oxidizing bacteria washing out; anaerobic treatment combined with rapid sludge discharge achieves both inhibition and washing out of nitrite-oxidizing bacteria.

[0004] The above methods all have the following problems: (1) Continuous large-scale sludge discharge to achieve nitrite oxidizing bacteria washing may lead to a decrease in sludge concentration in COD-deficient environments, slow growth of ammonia oxidizing bacteria, and limited abundance. (2) For large volumes of urban sewage, a large amount of energy will be consumed to maintain the temperature. (3) Controlling low DO will limit nitrification activity, and the system is prone to sludge bulking, resulting in sludge loss. (4) The use of chemical dosing and FA and FNA pretreatment have limited long-term effects, increase chemical costs, and additional pollutants, making them difficult to apply in actual water plants. Among them, anaerobic pretreatment can selectively inhibit nitrite oxidizing bacteria and, combined with rapid sludge discharge, can economically and effectively achieve nitrite accumulation, but it still has the problems of low activity and low abundance after ammonia oxidizing bacteria enrichment. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] In view of the aforementioned existing problems, the present invention is proposed.

[0007] Therefore, the present invention provides a highly active short-range nitration process for rapid start-up and long-term stable operation, which can solve the problems mentioned in the background art.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0009] This invention provides a highly active short-range nitration process for rapid start-up and long-term stable operation, comprising:

[0010] As a preferred embodiment of the high-activity short-cut nitrification rapid start-up and long-term stable operation process of the present invention, the process includes: inoculating sludge and performing anaerobic fermentation pretreatment, combined with rapid sludge discharge and manual removal of expanded sludge and sludge foam.

[0011] Control the sludge age in days, carry out sludge re-proliferation, enrich ammonia-oxidizing bacteria, and inhibit and wash away nitrite-oxidizing bacteria;

[0012] The system operates for a long period without sludge discharge, maintaining the abundance and activity of ammonia-oxidizing bacteria while controlling the abundance of nitrite-oxidizing bacteria.

[0013] The predation of protozoa and metazoa was used to control the proliferation of nitrite-oxidizing bacteria and control the nitrite accumulation rate in the reactor.

[0014] Real-time monitoring of dissolved oxygen, pH, ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen concentrations in the reactor, and regulation of influent ammonia nitrogen load and free ammonia concentration;

[0015] Intermittent aeration or microporous aeration is used to adjust the dissolved oxygen distribution and optimize the operating conditions of the short-cut nitrification reactor.

[0016] As a preferred embodiment of the high-activity short-cut nitrification rapid start-up and long-term stable operation process described in this invention, wherein: the inoculum sludge is from municipal wastewater treatment plant A 2 The process involves aerobic sludge from the O process, along with anaerobic fermentation-produced acid sludge. During inoculation, a long period of natural sedimentation is adopted. After 24 hours of sedimentation, the dense sludge is collected and aerated. The concentration of the inoculated sludge in the reactor is controlled at 10,000-8,000 mg / L, and the inoculation filling ratio is 100%. After sedimentation and concentration, the concentration of the inoculated sludge reaches 8-8.5 g / L.

[0017] As a preferred embodiment of the high-activity short-range nitrification rapid start-up and long-term stable operation process of the present invention, the anaerobic fermentation pretreatment stage maintains a local hypoxic environment by micro-aeration, controls the dissolved oxygen concentration to 0.2 mg / L, and provides an ammonia nitrogen matrix to retain ammonia-oxidizing bacteria and inhibit nitrite-oxidizing bacteria.

[0018] As a preferred embodiment of the high-activity short-cut nitrification rapid start-up and long-term stable operation process of the present invention, the rapid sludge discharge stage shortens the sedimentation time to 20-40 minutes and manually removes expanded sludge and sludge foam, thereby controlling the sludge age to less than 7 days.

[0019] As a preferred embodiment of the high-activity short-cut nitrification rapid start-up and long-term stable operation process described in this invention, the sludge re-proliferation stage controls the dissolved oxygen concentration within the range of 0.2-0.5 mg / L, stops sludge discharge and maintains the free ammonia concentration, selectively enriches ammonia-oxidizing bacteria and inhibits nitrite-oxidizing bacteria.

[0020] As a preferred embodiment of the high-activity short-cut nitrification rapid start-up and long-term stable operation process of the present invention, the predation of protozoa and metazoa is enhanced by adding trace elements to the influent, the trace elements including zinc ions, manganese ions and molybdenum ions.

[0021] As a preferred embodiment of the high-activity short-range nitrification rapid start-up and long-term stable operation process of the present invention, the intermittent aeration method uses microporous aeration discs for aeration, and the aeration volume is adjusted by a gas flow meter to control the dissolved oxygen distribution gradient in the reactor.

[0022] As a preferred embodiment of the high-activity short-cut nitrification rapid start-up and long-term stable operation process of the present invention, the short-cut nitrification reactor is a sequencing batch reactor (SBR) reactor, and the short-cut nitrification reactor operates for 4-6 cycles per day, each cycle including influent, aerobic stirring, sedimentation, drainage and idle stages.

[0023] As a preferred embodiment of the high-activity short-cut nitrification rapid start-up and long-term stable operation process of the present invention, wherein: under stable operation conditions, the nitrite accumulation rate of the short-cut nitrification reactor is maintained at over 90%, the abundance of ammonia-oxidizing bacteria exceeds 30%, and the reactor operates continuously for a certain period of time.

[0024] Compared with existing technologies, the advantages of this invention are that it enables the start-up of a highly active and abundant short-cut nitrification reactor by anaerobic treatment of high-concentration sludge, rapid sludge discharge, and inhibition of sludge re-proliferation in the environment. After coupling with an anaerobic ammonia oxidation reactor, a short-cut nitrification-anammonia oxidation process can be realized. The highly active short-cut nitrification provides stable influent conditions for anaerobic ammonia oxidation, shortening the treatment cycle. During short-cut nitrification, intermittent aeration and other methods can be used to achieve a combination of more processes (intermittent aeration, partial denitrification, biofilm) to achieve the removal of total nitrogen and the degradation of COD. The operation is simple, economical and effective. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 The diagram shows the running time of a high-activity short-range nitration rapid start-up and long-term stable operation process provided in one embodiment of the present invention. Detailed Implementation

[0027] To make the above-mentioned objects, features, and advantages of the present invention more readily understood, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0028] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0029] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0030] Example 1 is an embodiment of the present invention, which provides a high-activity short-cut nitrification rapid start-up and long-term stable operation process, including:

[0031] This application provides a solution to the aforementioned problems. The following sections will elaborate on how to achieve this highly active, short-range nitration process with rapid start-up and long-term stable operation, using multiple embodiments as examples:

[0032] Inoculate sludge and perform anaerobic fermentation pretreatment, combined with rapid sludge discharge and manual removal of expanded sludge and sludge foam;

[0033] Control the sludge age in days, carry out sludge re-proliferation, enrich ammonia-oxidizing bacteria, and inhibit and wash away nitrite-oxidizing bacteria;

[0034] The system operates for a long period without sludge discharge, maintaining the abundance and activity of ammonia-oxidizing bacteria while controlling the abundance of nitrite-oxidizing bacteria.

[0035] The predation of protozoa and metazoa was used to control the proliferation of nitrite-oxidizing bacteria and control the nitrite accumulation rate in the reactor.

[0036] Real-time monitoring of dissolved oxygen, pH, ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen concentrations in the reactor, and regulation of influent ammonia nitrogen load and free ammonia concentration;

[0037] Intermittent aeration or microporous aeration is used to adjust the dissolved oxygen distribution and optimize the operating conditions of the short-cut nitrification reactor.

[0038] Furthermore, the inoculated sludge is from municipal wastewater treatment plant A. 2 The process involves aerobic sludge from the O process, along with anaerobic fermentation-produced acid sludge. During inoculation, a long period of natural sedimentation is adopted. After 24 hours of sedimentation, the dense sludge is collected and aerated. The concentration of the inoculated sludge in the reactor is controlled at 10,000-8,000 mg / L, and the inoculation filling ratio is 100%. After sedimentation and concentration, the concentration of the inoculated sludge reaches 8-8.5 g / L.

[0039] Furthermore, the anaerobic fermentation pretreatment stage maintains a local hypoxic environment through micro-aeration, controlling the dissolved oxygen concentration to 0.2 mg / L, while providing an ammonia nitrogen substrate to retain ammonia-oxidizing bacteria and inhibit nitrite-oxidizing bacteria.

[0040] Furthermore, the rapid sludge removal stage shortens the settling time to 20-40 minutes and manually removes expanded sludge and sludge foam, keeping the sludge age below 7 days.

[0041] Furthermore, the sludge re-proliferation stage controls the dissolved oxygen concentration within the range of 0.2-0.5 mg / L, stops sludge discharge, maintains the free ammonia concentration, selectively enriches ammonia-oxidizing bacteria, and inhibits nitrite-oxidizing bacteria.

[0042] Furthermore, the predation of protozoa and metazoa is enhanced by adding trace elements to the influent, including zinc ions, manganese ions, and molybdenum ions.

[0043] Furthermore, the real-time monitoring of dissolved oxygen, pH value, ammonia nitrogen, nitrite nitrogen and nitrate nitrogen concentrations in the reactor is used to achieve precise control by adjusting the influent ammonia nitrogen load and aeration rate.

[0044] Furthermore, the intermittent aeration method uses microporous aeration discs for aeration, and the aeration volume is adjusted by a gas flow meter to control the dissolved oxygen distribution gradient in the reactor.

[0045] Furthermore, the short-cut nitrification reactor is a sequencing batch reactor (SBR) reactor, which operates for 4-6 cycles per day. Each cycle includes influent, aerobic stirring, sedimentation, effluent discharge, and idle phases.

[0046] Furthermore, under stable operating conditions, the nitrite accumulation rate of the short-cut nitrification reactor is maintained at over 90%, the abundance of ammonia-oxidizing bacteria exceeds 30%, and the reactor operates continuously for a certain period of time.

[0047] Example 2 is an embodiment of the present invention, which provides a highly active short-range nitrification process for rapid start-up and long-term stable operation, comprising:

[0048] A device and method for rapidly achieving high-rate short-cut nitrification by combining anaerobic treatment of high-concentration sludge with rapid sludge discharge and sludge screening, followed by sludge re-propagation without further sludge discharge. The device mainly consists of a sequencing batch reactor (SBR), an aeration pump, a gas rotor flow meter, an influent pump, an electric agitator, a microporous aeration disc, a dissolved oxygen probe, a pH probe, a DO / pH meter, a drain pump, and a timer. The influent, agitation, aeration, sedimentation, and effluent processes are all controlled by a pre-designed timer switch.

[0049] The artificial water distribution tank is connected to the SBR reactor via the first water pump;

[0050] The sequencing batch reactor (SBR) is equipped with an aeration pump, a gas rotor flow meter, a microporous aeration disc, a stirrer, a pH probe and a DO probe, and pH and DO monitors.

[0051] A device and method for rapidly obtaining short-cut nitrification with high-abundance AOB (anaerobic digestion of sludge) through anaerobic fermentation combined with rapid sludge discharge, sludge screening, and sludge re-propagation, characterized by the following features:

[0052] The inoculation sludge includes: some of the inoculation sludge for the short-cut nitrification SBR reactor is A2O full-process nitrification sludge from the municipal wastewater treatment plant. During inoculation, a long-term natural sedimentation method is adopted to greatly increase the sludge concentration. After 24 hours of sedimentation, the dense sludge is taken and aerated to obtain the sludge after further sedimentation. The concentration of inoculation sludge in the reactor is controlled at 10000-8000 mg / L, and the inoculation filling ratio is 100%.

[0053] The influent configuration includes: providing trace elements such as manganese and zinc, as well as ammonia nitrogen, to ensure the inhibition of FA in the reactor, while also providing trace elements to promote the predation of bacteria by protozoa and metazoa.

[0054] The SBR reactor was operated at 30-35℃, with DO controlled at 0-0.2 mg / L. Full aeration was performed throughout the 6-hour cycle, with each aeration time lasting 5 hours. Short-cut nitrification was initiated when the influent ammonia nitrogen concentration was 100-200 mg / L. After 3-7 days of low-aeration anaerobic treatment, the reactor's nitrification activity was completely inhibited due to the low DO concentration. Once the sludge pyrolysis and endogenous respiration stages were completed and the effluent ammonia nitrogen level was lower than the influent level, the short-cut nitrification process could be started.

[0055] The reactor operates 4-6 cycles per day. Each cycle includes 10 minutes of influent, 4 hours and 50 minutes or 2 hours and 50 minutes of aerobic stirring, 40 minutes of sedimentation, 10 minutes of effluent discharge, and 10 minutes of idle time, totaling 6-4 hours. During startup, a 6-hour cycle is used until the reactor starts up successfully. Due to the high activity and the need to control the effluent ratio, the cycle time can be adjusted, such as reducing the aerobic stirring and sedimentation time, thus changing the cycle to 4 hours.

[0056] The specific operation steps for one cycle are as follows:

[0057] Water intake stage: Water is introduced from the raw water tank through the water intake pump, and the water intake volume is set to 40% of the effective volume of the reactor, with an intake time of 10 minutes.

[0058] Aerobic stirring operation stage (3-5 hours): After the water intake is completed, the aerobic operation stage begins. Aeration can be carried out through sand core aerators. During the stable operation stage, in order to ensure stable effluent and achieve stable control of the effluent nitrite nitrogen and ammonia nitrogen ratio, microporous aerator discs are used to ensure stable aeration efficiency. At the same time, a gas flow meter is used to control the aeration volume. Stirring is achieved by a stirrer, and the stirring speed and aeration volume are controlled to ensure that the DO in the reactor is stable at 0.2 mg / L. During this period, the reactor ammonia oxidation rate, nitrite accumulation rate, effluent nitrate, nitrite and ammonia concentrations all change drastically with the anaerobic treatment stage, rapid sludge discharge stage and sludge re-proliferation stage during the start-up period.

[0059] After aeration, the reactor enters a settling and drainage idle phase. During startup, due to the influence of sludge concentration and anaerobic environment, the sludge SV30 in the reactor is close to 60%, and anaerobic sludge bulking and sludge foaming occur. Sludge pyrolysis and endogenous respiration are still ongoing, resulting in a large amount of floating sludge and flocs in the effluent. By reducing the settling time to 20 minutes, sludge with poor settling performance is discharged with the effluent. At the same time, sludge foam on the water surface and suspended flocs in the supernatant are manually removed and discarded using a fine mesh net. After two rapid sludge discharges and sludge re-proliferation processes, the sludge settling performance of the reactor is greatly improved, resulting in clear effluent.

[0060] The system enters the next cycle and repeats the bc phase;

[0061] It should be noted that the time control device controls the reactor's water intake, stirring, aeration, and drainage processes.

[0062] This invention relates to an apparatus and method for rapidly achieving short-cut nitrification through anaerobic fermentation pretreatment of high-concentration sludge combined with rapid sludge discharge at low sludge age and sludge re-proliferation, resulting in high-abundance AOB (anaerobic bloat) and highly active short-cut nitrified sludge. This invention has the following advantages:

[0063] This process uses high-concentration, fully nitrified sludge as inoculum. There are no special requirements for the aerobic sludge used as inoculum; concentrated sludge from a sedimentation tank can be used on-site. Anaerobic treatment can be performed by providing a small amount of aeration and stirring, saving energy. During anaerobic treatment, two methods can be used: providing a substrate such as ammonia nitrogen or not providing a substrate. Aeration can also be achieved by utilizing the sludge's endogenous respiration to consume oxygen while providing a small amount of aeration, or by stopping aeration and performing only anaerobic stirring. The difference lies in the fact that providing a small amount of aeration can maintain a localized anoxic environment during anaerobic treatment, ensuring the survival of AOB (ammonia-bound bacteria), but it also easily leads to NOB (nitrogenous oxygen-bound bacteria) retention, which is difficult to completely remove through subsequent processes.

[0064] After anaerobic treatment, the high sludge concentration leads to sludge pyrolysis and endogenous respiration, resulting in the proliferation of anaerobic bacteria and a decrease in sludge concentration. Microorganisms are inhibited by factors such as fatty acids (FA) and predation. During the subsequent re-proliferation process, the abundance of aerobic bacteria (AOB) increases rapidly, while the abundance of nitrogenous bacteria (NOB) decreases sharply. During this process, substrate-free anaerobic treatment can be used to completely remove NOB, followed by AOB re-proliferation to achieve AOB enrichment. No chemicals need to be added during the enrichment start-up process; the main operational procedures can be controlled through stirring, aeration, sludge removal, manual removal of floating sludge and foam, and the addition of trace elements. The operation is simple, economical, and effective.

[0065] To achieve stable reactor operation, the aeration rate needs to be adjusted based on factors such as actual operating temperature. Due to the high activity of the sludge, a stable DO supply must be ensured while preventing NOB proliferation caused by rising DO levels. Therefore, stable and effective aeration equipment, such as microporous aeration discs, is required. The reactor needs to maintain DO levels below 0.2 mg / L. Given the high sludge activity, microporous aeration discs can be used for aeration, providing stable oxygen supply while controlling DO levels, saving aeration volume, achieving differential growth of AOB and NOB, and providing a stable and sufficient oxygen supply. Alternatively, intermittent aeration can be used to simultaneously decarbonize and oxidize the wastewater, while stably controlling the effluent ratio to provide favorable influent conditions for subsequent anaerobic ammonia oxidation.

[0066] After enrichment with high-abundance AOB sludge, the short-cut nitrification activity reaches 100 mgN / gMLVSS·h, which places higher demands on aeration efficiency. At the same time, the reaction rate is greatly improved, and the volumetric activity can reach 128 gN / m3·h, reducing the actual operation requirements for HRT. Furthermore, due to the good enrichment effect, sludge discharge is no longer required, which helps to reduce infrastructure investment and provides sufficient space for subsequent deep treatment of anaerobic ammonia oxidation. It also provides sufficient potential to withstand low-temperature operation.

[0067] After the reactor is started up with highly concentrated aerobic sludge, sludge pyrolysis, sludge bulking, and endogenous respiration occur, producing a large amount of sludge flocs, which provide food for protozoa and metazoa. After the start-up process, the remaining protozoa and micro-metazoa are enhanced by trace elements and tend to prey on NOB during the long-term operation of the reactor when sludge discharge is stopped. Meanwhile, AOB community abundance exceeds 30% and grows rapidly and remains stable under suitable operating conditions.

[0068] When NOB proliferates in the reactor after long-term operation, or when NOB bacteria are introduced into the influent leading to an increase in effluent nitrate nitrogen, predation by protozoa and metazoa can continuously cleanse the NOB bacteria. In cases of large-scale NOB proliferation, a similar start-up method can be used to restart the sludge, or anaerobic treatment, the introduction of protozoa and micrometazoa can be employed to kill NOB. After treatment, AOB bacteria will then re-enter the proliferation phase.

[0069] Example 3, referring to Figure 1 This is one embodiment of the present invention, which provides a highly active short-range nitration process for rapid start-up and long-term stable operation. To verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculations and simulation experiments.

[0070] The reactor used in this method is an SBR (Self-Bio Reactor), cylindrical in shape with an effective volume of 5L, made of glass, with an outer circulating water bath layer to control the temperature at 22-33℃. A microporous aeration disc is installed at the bottom of the reactor, and the required dissolved oxygen can be controlled by adjusting the flow meter. A stirrer ensures mixing of the sludge and water during the reaction, and the influent and effluent pumps are controlled by a timed switch. The influent contains ammonia nitrogen and trace elements.

[0071] The specific details of the influent water quality during the experiment are shown in the table below:

[0072] Table 1 Influent Water Quality Table

[0073]

[0074] Table 2. Trace Element Composition Table

[0075]

[0076] During system operation, the wastewater treatment process is as follows: Artificially dispensed water from the influent tank is pumped into the short-cut nitrification reactor by the influent pump. Aeration is achieved throughout the process via microporous aeration discs, while simultaneously controlling the aeration rate for anoxic stirring, maintaining dissolved oxygen (DO) within the range of 0.1-0.2. The reactor's anaerobic environment is maintained by utilizing the rapid consumption of dissolved oxygen by highly active sludge and adjusting the aeration rate. After the anaerobic treatment during startup, rapid sludge removal, and sludge re-proliferation stages, stable short-cut nitrification can be achieved by adjusting the effluent ammonia nitrogen concentration and employing intermittent aeration, among other operating conditions.

[0077] An apparatus and method for high-concentration sludge anaerobic fermentation combined with rapid sludge discharge and sludge re-proliferation, characterized by comprising the following:

[0078] Start-up of short-cut nitrification:

[0079] First, a high concentration of fully nitrified sludge was inoculated into the reactor: the inoculated nitrified sludge was aerobic sludge from the A2O treatment process of a certain urban wastewater treatment plant. After sedimentation and concentration, the sludge concentration in the reactor after inoculation was 8-8.5 g / L.

[0080] The working volume of the sequencing batch reactor is 5L;

[0081] The influent is artificially prepared and contains ammonia nitrogen, sodium bicarbonate and trace elements. The influent NH4+-N: 150-200mg / L. It runs 4-6 cycles per day, and the influent-to-outfluent ratio is 2:5.

[0082] Short-cut nitrification was initiated at a normal temperature of 32℃. Artificially prepared feed water was pumped into the reactor from the feed tank via the feed pump for 10 minutes.

[0083] The reactor starts aeration and stirring to control the aeration rate to achieve DO below 0.2 mg / L. During the operation cycle, the effluent ammonia nitrogen concentration is maintained to create an FA-inhibiting environment. During the sedimentation stage of the start-up period, the sedimentation time needs to be controlled to eliminate sludge with poor sedimentation performance. After drainage, the reactor enters the next cycle after an idle period.

[0084] The initially inoculated high-concentration sludge requires anaerobic treatment through an anaerobic fermentation stage. Since the inoculated sludge concentration reaches 8 g / L, significant sludge loss is likely during this stage due to the influence of actual sedimentation performance, causing the sludge concentration to gradually decrease. This stage can employ either micro-aeration without ammonia nitrogen substrate or micro-aeration with ammonia nitrogen substrate, relying on the sludge's endogenous respiration to deplete dissolved oxygen. The absence of ammonia nitrogen ensures complete elimination of NOB, while the presence of ammonia nitrogen substrate effectively retains AOB but leaves NOB residue. Simultaneously, because the reactor consistently supplies DO, aerobic microorganisms continuously utilize the internal carbon source, leading to aerobic starvation and eventual lysis and death. The dead microorganisms provide organic matter and polysaccharides for anaerobic microorganisms to utilize for anaerobic fermentation, thus preserving heterotrophic anaerobic bacteria. After treatment, a rapid sludge discharge stage begins.

[0085] During the rapid sludge removal phase, manual sludge removal is performed daily to ensure a sedimentation time (SRT) of less than 10 days. Simultaneously, due to the low dissolved oxygen environment, sludge bulking occurs in the reactor, generating sludge foam. Manual cleaning of the sludge foam on the reactor surface shortens the settling time, removing the bulky sludge that is difficult to settle, resulting in a rapid decrease in sludge concentration and an SRT below 7 days. This causes effluent ammonia nitrogen to gradually recover, while nitrate nitrogen rises rapidly before decreasing rapidly due to sludge loss. NAR rapidly increases to 90% (leading to rapid accumulation of nitrite nitrogen, causing a decrease in pH; at this point, sufficient sodium bicarbonate is added to the influent to provide alkalinity). Once effluent nitrate nitrogen is extremely low or disappears (during which anaerobic treatment can be used to completely eliminate NOB), the sludge re-proliferation phase begins.

[0086] During the sludge re-propagation stage, since the sludge concentration is below 1 g / L, it is necessary to further control the aeration rate and maintain the inhibitory environment of the reactor by controlling the effluent ammonia nitrogen concentration and stopping sludge discharge to achieve selective AOB propagation. NOB, on the other hand, has extremely low abundance and is inhibited, making effective propagation difficult. As AOB propagation progresses and effluent nitrite nitrogen gradually recovers, and the AOB abundance exceeds 40% after re-propagation, a second re-propagation process can be performed to achieve sludge washing, optimize sedimentation performance, and improve activity. After re-propagation, due to good sedimentation performance, the reactor no longer experiences sludge loss, and manual sludge discharge is no longer required. The reactor is then operated stably until it stabilizes. During this period, NAR stabilizes at 90%. After stable operation, the short-cut nitrification activity of the sludge can reach 100-200 mgN / g(VSS)·h, while nitrite oxidation activity is difficult to detect and remains below 0.5 mgN / g(VSS)·h even after long-term operation.

[0087] The reactor was successfully started up within 40-60 days. Once the reactor was running stably and the sludge concentration increased, stable effluent at different temperatures could be achieved by simultaneously controlling the temperature and aeration rate, providing an effective influent environment for AMX. Meanwhile, protozoa and micrometazoans preyed on the reactor, exhibiting preferential predation despite the potential intake of NOB, thus controlling NOB bacteria.

[0088] Because the obtained sludge has extremely high AOB abundance and large AOB activity potential, the reactor is highly resistant to adverse environments such as FA inhibition, FNA inhibition, low DO environment, low temperature, and low alkalinity. After operating in a harmful environment, it can still ensure the treatment effect and achieve effective recovery by operating without sludge discharge.

[0089] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

[0090] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of this application can be implemented in various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0091] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0092] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0093] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0094] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0095] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A highly active, short-range nitration process for rapid start-up and long-term stable operation, characterized in that: include, Inoculate sludge and perform anaerobic fermentation pretreatment, combined with rapid sludge discharge and manual removal of expanded sludge and sludge foam; Control the sludge age in days, carry out sludge re-proliferation, enrich ammonia-oxidizing bacteria, and inhibit and wash away nitrite-oxidizing bacteria; The system operates for a long period without sludge discharge, maintaining the abundance and activity of ammonia-oxidizing bacteria while controlling the abundance of nitrite-oxidizing bacteria. The predation of protozoa and metazoa was used to control the proliferation of nitrite-oxidizing bacteria and control the nitrite accumulation rate in the reactor. Real-time monitoring of dissolved oxygen, pH, ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen concentrations in the reactor, and regulation of influent ammonia nitrogen load and free ammonia concentration; Intermittent aeration or microporous aeration is used to adjust the dissolved oxygen distribution and optimize the operating conditions of the short-cut nitrification reactor.

2. The high-activity short-range nitration rapid start-up and long-term stable operation process as described in claim 1, characterized in that: The inoculated sludge is from municipal wastewater treatment plant A. 2 The process involves aerobic sludge from the O process, along with anaerobic fermentation-produced acid sludge. During inoculation, a long period of natural sedimentation is adopted. After 24 hours of sedimentation, the dense sludge is collected and aerated. The concentration of the inoculated sludge in the reactor is controlled at 10,000-8,000 mg / L, and the inoculation filling ratio is 100%. After sedimentation and concentration, the concentration of the inoculated sludge reaches 8-8.5 g / L.

3. The high-activity short-cut nitration rapid start-up and long-term stable operation process as described in claim 2, characterized in that: The anaerobic fermentation pretreatment stage maintains a local hypoxic environment through micro-aeration, controlling the dissolved oxygen concentration at 0.2 mg / L, while providing an ammonia nitrogen substrate to retain ammonia-oxidizing bacteria and inhibit nitrite-oxidizing bacteria.

4. The high-activity short-range nitration rapid start-up and long-term stable operation process as described in claim 3, characterized in that: The rapid sludge removal stage shortens the settling time to 20-40 minutes and manually removes expanded sludge and sludge foam, keeping the sludge age below 7 days.

5. The high-activity short-cut nitration rapid start-up and long-term stable operation process as described in claim 4, characterized in that: The sludge re-proliferation stage controls the dissolved oxygen concentration within the range of 0.2-0.5 mg / L, stops sludge discharge, maintains the free ammonia concentration, selectively enriches ammonia-oxidizing bacteria, and inhibits nitrite-oxidizing bacteria.

6. The high-activity short-range nitration rapid start-up and long-term stable operation process as described in claim 5, characterized in that: The predation of protozoa and metazoa is enhanced by adding trace elements to the influent, including zinc ions, manganese ions, and molybdenum ions.

7. The high-activity short-range nitration rapid start-up and long-term stable operation process as described in claim 6, characterized in that: The system monitors the concentrations of dissolved oxygen, pH, ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the reactor in real time, and achieves precise control by adjusting the influent ammonia nitrogen load and aeration rate.

8. The high-activity short-cut nitration rapid start-up and long-term stable operation process as described in claim 7, characterized in that: The intermittent aeration method uses microporous aeration discs for aeration, and the aeration volume is adjusted by a gas flow meter to control the dissolved oxygen distribution gradient in the reactor.

9. The high-activity short-range nitration rapid start-up and long-term stable operation process as described in claim 8, characterized in that: The short-cut nitrification reactor is a sequencing batch reactor (SBR) reactor. The short-cut nitrification reactor operates for 4-6 cycles per day, and each cycle includes influent, aerobic stirring, sedimentation, effluent discharge, and idle phases.

10. The high-activity short-range nitration rapid start-up and long-term stable operation process as described in claim 9, characterized in that: Under stable operating conditions, the nitrite accumulation rate of the short-path nitrification reactor is maintained at over 90%, the abundance of ammonia-oxidizing bacteria exceeds 30%, and the reactor operates continuously for a certain period of time.

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