CN103226366B - The control method of short distance nitration Anammox integral type denitrification process - Google Patents

Abstract

The control methods of the short-cut nitrification-anammox integrated SBR denitrification process are respectively the dissolved oxygen-ammonia nitrogen control method and the pH-ammonia nitrogen control method; among them: the dissolved oxygen-ammonia nitrogen control method is to use the dissolved oxygen online electrode and the ammonia nitrogen online electrode , the aeration rate is controlled by the dissolved oxygen online electrode, and then the NO ₂ ^‑ ‑N concentration level in the SBR is controlled, and the short-range nitrification and anammox reaction are carried out simultaneously in the same SBR, and the ammonia nitrogen retention concentration in the SBR is controlled by the ammonia nitrogen online electrode ; The pH-ammonia nitrogen control method is to use the pH online electrode and the ammonia nitrogen online electrode to control the stop of the aeration system through the pH decrease ΔpH1 in the nitrification stage, and to control the opening of the aeration system through the pH increase ΔpH2 in the anammox stage. The short-range nitrification of ammonia nitrogen and anaerobic ammonium oxidation are carried out alternately in the same SBR, and the residual concentration of ammonia nitrogen in the SBR is controlled by the ammonia nitrogen online electrode.

Description

Control method of short-cut nitrification-anammox integrated denitrification process

technical field

The invention belongs to the field of novel biological denitrification, and in particular relates to two control methods of dissolved oxygen-ammonia nitrogen and pH-ammonia nitrogen in a short-range nitrification-anammox integrated SBR (sequencing batch reactor) denitrification process.

Background technique

With the development of society and the improvement of residents' living standards, the main problem facing my country's water environment has changed from the traditional oxygen-consuming pollution to eutrophication. Since ammonia nitrogen is a substance that consumes oxygen and causes eutrophication of water bodies, Therefore, ammonia nitrogen plays an important role in the transformation of the causes of water pollution in my country. Based on this, my country's "Twelfth Five-Year Plan" clearly added the emission reduction indicators of ammonia nitrogen binding water pollutants, so how to reduce ammonia nitrogen emissions is an important problem facing my country's environmental protection.

At present, conventional biological nitrification/denitrification is still the main method for denitrification of sewage. Although it has cost advantages compared with physical and chemical denitrification methods, it still has disadvantages such as low efficiency, high energy and material consumption, and large amount of residual sludge [Fux, C. and H. Siegrist. 2004. Nitrogen removal from sludge digester liquids by nitrification/denitrification or partial nitritation/anammox: environmental and economical considerations [J]. Water Science and Technology, 50(10): 19-26]. With the in-depth understanding of nitrogen conversion pathways, a series of new nitrogen removal processes have been developed to address the inherent shortcomings of traditional nitrogen removal processes. Anaerobic Ammonium Oxidation (Anammox) was produced in the 1990s [Mulder, A., A.A. Vandegraaf, L.A. Robertson, et al. 1995. Anaerobic ammonium oxidation discovered in a denitrifying fluidized bed reactor [J]. FemsMicrobiology Ecology ,16(3):177-183], is currently the most promising new biological denitrification technology, and its reaction can be expressed as:

Since the Anammox reaction uses NH ₄ ⁺ -N and NO ₂ ^- -N as substrates, and the content of NO ₂ ^- -N in general wastewater is very low, it is a necessary condition for Anammox to realize NO ₂ ^- -N accumulation through short-range nitrification . Compared with the traditional denitrification method, the short-cut nitrification-ANAMMOX combined process can save about 60% of the aeration rate, does not need an external carbon source at all, and has a low sludge output, which is especially suitable for treating low C/N ratio and high ammonia nitrogen wastewater [Fux C, Boehler M, et al. Biological treatment of ammonium-rich wastewater by partial nitritation and subsequent anaerobicammonium oxidation (anammox) in a pilot plant [J]. Journal of Biotechnology, 2002, 99 (3): 295-306].

For the integrated combination of short-range nitrification and anammox, there are CANON, OLAND, DEMON, SNAP and other processes. The main functional bacteria are ammonia oxidizing bacteria (AOB) and Anammox bacteria, which are in the same reaction system and have complex interrelationships, mainly in dissolved oxygen and nitrite. A certain amount of dissolved oxygen is the necessary electron acceptor for AOB to oxidize ammonia nitrogen, but when its concentration is too high, it will have an inhibitory effect on Anammox bacteria. Therefore, micro-aeration can be used to control the DO concentration in the reaction process at a low level to simultaneously Satisfy the physiological needs of the two bacteria. NO ₂ ^- -N is not only the short-range nitrification product of AOB, but also the reaction substrate of Anammox bacteria, but when its concentration exceeds a certain value, it will also inhibit Anammox bacteria. Since the direct real-time online monitoring method of NO ₂ ^- -N concentration is not yet mature, according to the short-term nitrification acid production characteristics of ammonia nitrogen, the amount of NO ₂ ^- -N produced in the system can be controlled by controlling the pH change. Therefore, at present, the actual operation of the short-range nitrification-ANAMMOX combined denitrification process is mainly controlled by controlling the dissolved oxygen or pH of the system.

However, the control of DO and pH is only a process control, and in order to strictly ensure that the short-cut nitrification-ANAMMOX integrated process will not accumulate NO ₂ ^- -N in actual operation, it is necessary to retain a certain concentration of NO 2 - -N at the end of the reaction. NH ₄ ⁺ -N, which is essential for the long-term stable operation of the overall system. However, the current sewage treatment facilities maintain a fixed hydraulic retention time (HRT) in the actual operation process. In this way, when the ammonia nitrogen load in the influent fluctuates, the ammonia nitrogen concentration in the effluent water will also be affected, and a certain residual ammonia nitrogen cannot be guaranteed. Therefore, it is possible NO ₂ ^- -N accumulation will occur. Especially when the treatment object is industrial wastewater with high ammonia nitrogen concentration, the ammonia nitrogen load will fluctuate violently, which will bring serious impact load, and make the normal operation of the system face the danger of collapse.

In addition to municipal sludge water (sludge digestion supernatant, digested sludge mechanical dehydration filtrate), the sources of high-concentration ammonia nitrogen wastewater mainly include production wastewater from industrial industries such as fertilizer production, pharmaceuticals, petrochemicals, and coking, whose water quality fluctuates violently , so there is no perfect control method to ensure the flexible application of short-cut nitrification-anammox combination process to the above-mentioned industries. Therefore, it is necessary to propose a new control mode that can adapt to the objective conditions of severe fluctuations in water quality.

Contents of the invention

The purpose of the present invention is to provide a control method for the short-range nitrification-anammox integrated SBR denitrification process.

In order to achieve the above object, the control method of the short-range nitrification-anammox integrated SBR denitrification process provided by the present invention is respectively a dissolved oxygen-ammonia nitrogen control method and a pH-ammonia nitrogen control method; wherein:

The dissolved oxygen-ammonia nitrogen control method is to use the dissolved oxygen online electrode and the ammonia nitrogen online electrode to control the aeration rate through the dissolved oxygen online electrode, and then control the NO ₂ ^- -N concentration level in the SBR, and control the ammonia nitrogen retention concentration in the SBR through the ammonia nitrogen online electrode ;

The pH-ammonia nitrogen control method is to use the pH online electrode and the ammonia nitrogen online electrode to control the stop of the aeration system through the pH decrease ΔpH1 in the nitrification stage, and to control the opening of the aeration system through the pH increase ΔpH2 in the anammox stage, so as to achieve Short-cut nitrification of ammonia nitrogen and anaerobic ammonium oxidation are carried out alternately in the same SBRSBR denitrification device. The ammonia nitrogen retention concentration in the SBR is controlled by the ammonia nitrogen online electrode.

Said control method, wherein, the whole short-cut nitrification-ANAMMOX integrated SBR denitrification process is divided into six steps: water intake, reaction, stirring, sedimentation, drainage and idle.

The control method, wherein the dissolved oxygen-ammonia nitrogen control method controls the concentration of dissolved oxygen in the SBR to be below 1.00 mg·L ^-1 , to control the concentration of NO ₂ ^- -N in the aerobic stage to be below 10.00 mg·L ^-1 , and to control the concentration of ammonia nitrogen The remaining concentration is 10.00～30.00mg·L ^-1 .

The control method, wherein the pH-ammonia nitrogen control method controls the NO ₂ ^- -N concentration in the aerobic stage to be below 10.00 mg·L ^-1 , and controls the ammonia nitrogen retention concentration to be 10.00-30.00 mg·L ^-1 .

Compared with the prior art, the control method of the present invention has the advantages of:

(1) Three online electrodes of DO, pH and ammonia nitrogen are used to monitor the process parameters in the SBR in real time, and the overall operation is controlled by the PLC system, which has a high degree of automation and is easy to operate and maintain.

(2) Integrate process control and end point control, flexibly respond to the fluctuation of ammonia nitrogen load in the influent, resist the impact load of ammonia nitrogen, and ensure the stability of effluent water quality.

(3) The use of NH ₄ ⁺ -N electrodes to strictly control a certain residual concentration of ammonia nitrogen can avoid the accumulation of NO ₂ ^- -N, thereby effectively controlling the occurrence of the inhibition of Anammox bacteria, which is conducive to the stability of long-term operation.

Description of drawings

Fig. 1 is a schematic flow chart of SBR operation under the dissolved oxygen-ammonia nitrogen control method and the pH-ammonia nitrogen control method of the present invention.

Fig. 2 is a PLC logical schematic diagram of the dissolved oxygen-ammonia nitrogen control method of the present invention.

Fig. 3 is a PLC logical schematic diagram of the pH-ammonia nitrogen control method of the present invention.

Fig. 4 is the online electrode monitoring results of pH, DO, EC and ammonia nitrogen in a single cycle of the short-cut nitrification-anammox integrated SBR process under the dissolved oxygen-ammonia nitrogen control method of the present invention.

Figure 5 shows the changes of NH ₄ ⁺ -N, NO ₃ ^- -N, NO ₂ ^- -N and TN in a single cycle of the short-cut nitrification-anammox integrated SBR process under the dissolved oxygen-ammonia nitrogen control method of the present invention .

Fig. 6 is the pH fluctuation control range value of the short-cut nitrification-anammox integrated SBR process under the pH-ammonia nitrogen control method of the present invention.

Fig. 7 is the online electrode monitoring results of pH, DO, EC and ammonia nitrogen in a single cycle of the short-range nitrification-anammox integrated SBR process under the pH-ammonia nitrogen control method of the present invention.

Fig. 8 shows the changes of NH ₄ ⁺ -N, NO ₃ ^- -N, NO ₂ ^- -N and TN in a single cycle of the short-cut nitrification-ANAMMOX integrated SBR process under the pH-ammonia nitrogen control method of the present invention.

Fig. 9 is a schematic diagram of the short-cut nitrification-anammox integrated SBR denitrification device of the present invention.

detailed description

The control method of the present invention can be applied to the biological denitrification treatment of a series of low C/N ratio and high ammonia nitrogen wastewater including sludge digestion liquid, coking wastewater, nitrogen fertilizer production wastewater, pharmaceutical wastewater and the like.

The invention aims at the defect of the existing control method of the short-range nitrification-anammox combination denitrification process, and proposes two control methods of dissolved oxygen-ammonia nitrogen and pH-ammonia nitrogen. The implementation of the control method specifically uses DO, pH and NH ₄ ⁺ -N three online electrodes to monitor the operation of the short-range nitrification-ANAMMOX integrated SBR in real time, and the control parameters are obtained and sent to the PLC operating the logic of the two combined control modes The system controls the implementation of each step of the short-range nitrification-anammox integrated SBR denitrification device through the logical judgment of the joint control mode, specifically the six stages of SBR (water intake, reaction, stirring, sedimentation, drainage and idle )control.

1. The specific implementation of the control process of the dissolved oxygen-ammonia nitrogen joint control method is divided into the following steps:

(1) The SBR denitrification device starts to operate, the stirring paddle starts, the water inlet pump starts, the SBR denitrification device starts to feed water, and the liquid level sensor detects the liquid level in the SBR denitrification device, and feeds back the liquid level value to the PLC control system , when the liquid level reaches the set high liquid level, it controls the stop of the water inlet pump.

(2) After the water inlet pump stops, the aeration system starts, the DO concentration in the system is monitored by the dissolved oxygen online electrode, and the DO concentration in the SBR denitrification device is controlled through the flow meter to ensure that NO ₂ ^- -N will not accumulate. Short-cut nitrification and anaerobic ammonium oxidation occur simultaneously, and the ammonia nitrogen online electrode monitors the change of ammonia nitrogen concentration in the SBR denitrification device in real time.

(3) As the two reactions of short-range nitrification and anaerobic ammonium oxidation continue, the ammonia nitrogen in the SBR denitrification device is continuously consumed, and the readings of the ammonia nitrogen electrode continue to decrease. When the set ammonia nitrogen retention concentration is reached, the aeration system stop.

(4) After the aeration system stops working, the DO concentration in the SBR denitrification device will drop rapidly to 0.00 mg·L ^-1 , and the SBR enters the stirring stage. Set a certain stirring time to ensure that the generated NO ₂ ^- -N is completely removed by anaerobic ammonium oxidation reaction, and the generated N ₂ escapes from the water, thereby improving the sludge settling performance in the SBR denitrification device.

(5) After the stirring time is completed, the stirring paddle stops working, and the SBR denitrification device enters the sedimentation stage, and the sludge settles at the bottom of the SBR denitrification device to realize the separation of mud and water.

(6) After the precipitation time is completed, the drainage system starts to discharge the supernatant. The liquid level sensor detects the liquid level in the SBR denitrification device and feeds back the liquid level value to the PLC control system. When the liquid level reaches the set value When the liquid level is low, the control drainage system stops.

(7) After the liquid level sensor detects the low liquid level value, the drainage system stops, the stirring paddle is turned on, and the SBR denitrification device enters the idle stage. Set the idle time and wait for the next water intake.

(8) After the idle time is completed, the water inlet pump is turned on, and the SBR denitrification device enters the next cycle, and (1)-(7) are repeated. The system stops automatically after all cycles are completed.

2. The specific implementation of the control process of the pH-ammonia nitrogen joint control mode is divided into the following steps:

(1) The system starts to run, the stirring paddle starts, the water inlet pump starts, and the SBR denitrification device starts to feed water. The liquid level sensor detects the liquid level in the SBR denitrification device and feeds back the liquid level value to the PLC control system. When the liquid When the liquid level reaches the set high level, it controls the stop of the water inlet pump.

(2) After the water inlet pump stops, the aeration system starts, and the dissolved oxygen electrode monitors the DO concentration in the system to avoid the inhibition of Anammox bacteria due to its high concentration. The pH electrode monitors the pH changes in the system in real time, and sets the pH drop range ΔpH1. With the short-range nitrification of NH ₄ ⁺ -N, NO ₂ ^- -N is continuously generated, and the pH continues to decrease. When the pH drop reaches the set value, The aeration system stopped working.

(3) After the aeration system stops working, the anammox reaction continues to consume NO ₂ ^- -N, and the pH gradually rises. Set the pH increase ΔpH2, when the pH increase reaches the set value, the aeration system is turned on, the short-range nitrification of NH ₄ ⁺ -N starts again, NO ₂ ^- -N is regenerated, and the pH drop is continuously monitored, ( 2)-(3) cycle is repeated.

(4) With the cycle start and stop of the aeration system, short-range nitrification and anammox continue alternately, the NH ₄ ⁺ -N in the raw water is continuously consumed, and the reading of the ammonia nitrogen electrode continues to decrease. When the set ammonia nitrogen is reached When the concentration value is saved, the aeration system stops working.

(5) After the aeration system stops working, the DO concentration in the SBR denitrification device will drop rapidly to 0.00 mg·L ^-1 , and the SBR denitrification device enters the stirring stage. Set a certain stirring time to ensure that the generated NO ₂ ^- -N is completely consumed by the anaerobic ammonium oxidation reaction, and the generated N ₂ escapes from the water, thereby improving the sludge settling performance in the SBR denitrification device.

(6) After the set stirring time is completed, the stirring paddle stops working, and the SBR denitrification device enters the sedimentation stage, and the sludge settles at the bottom of the SBR denitrification device to realize the separation of mud and water.

(7) After the precipitation time is completed, the drainage system is opened to discharge the supernatant of the SBR denitrification device. The liquid level sensor detects the liquid level in the SBR denitrification device and feeds back the liquid level value to the PLC control system. When the liquid When the level reaches the set low level, the control drainage system stops.

(8) After the liquid level sensor detects the low liquid level value, the drainage system stops, the stirring paddle is turned on, and the SBR denitrification device enters the idle stage. Set the idle time and wait for the next water intake.

(9) After the idle time is completed, the water inlet pump is turned on, and the SBR denitrification device enters the next cycle, and (1)-(8) are repeated. The system stops automatically after all cycles are completed.

The start-stop control of the aeration system mentioned above refers to the start-stop control of the aeration pump for the system that uses the direct air supply of the aeration pump; Valve opening and closing control.

The rotating speed of the stirring paddle is set according to the actual stirring effect.

The dissolved oxygen concentration in the control SBR denitrification device can be adjusted according to the accumulation of NO ₂ ^- -N, and DO<1.00mg·L ^-1 should be controlled normally.

The NO ₂ ^- -N accumulation generally refers to the NO ₂ ^- -N concentration >10.00 mg·L ^-1 .

The ammonia nitrogen retention concentration value is usually set at 10.00-30.00 mg·L ^-1 .

_The duration of stirring can be set according to the effect of N escape.

The settling time can be set according to the sludge settling characteristics.

The high and low liquid level values set by the liquid level sensor indicate the effective volume of the system and the exchange volume per cycle, and the exchange rate per cycle of the SBR denitrification device is usually ranging from 10% to 50%.

The pH drop ΔpH1 setting refers to the drop value based on the pH value when the aeration system is turned on, and it should be set according to the activity of ammonia oxidizing bacteria (AOB).

The pH increase ΔpH2 setting refers to the increase value based on the pH value when the aeration system stops, and should be set according to the activity of the anammox bacteria.

Describe in detail below in conjunction with accompanying drawing.

Fig. 9 is a schematic diagram of the short-cut nitrification-anammox integrated SBR denitrification device of the present invention. The water storage tank 1 is equipped with a water inlet pump 1.1 and a push flow pump. The SBR denitrification device is an open cylindrical tank with an overflow pipe on the upper part, an emptying pipe on the lower part, and water outlet valves at different heights on the side. . SBR is equipped with liquid level sensor 5, DO electrode 6.1, pH electrode 6.2, ORP electrode 6.3, EC electrode 6.4 and ammonia nitrogen electrode 7.1, all of which are connected to PLC automatic control system 9 through transmitters 6 and 7.

The PLC automatic control system is equipped with on-site touch panel 8 control and remote computer 10 control, which is convenient for on-site operation and remote monitoring of the SBR denitrification device during automatic operation. The SBR denitrification device is also equipped with a stirring paddle 3.1 that can be adjusted in speed, and a microporous aeration plate 3.2 is arranged in the center of the bottom, and an insulation cover 2.2 is wrapped outside the SBR denitrification device and connected to the constant temperature water bath 2 through the water bath circulation pump 2.1 . In addition, the aeration pipeline is equipped with a dosing valve 3.3 and an air compressor 4, and the compressed air enters the microporous aeration disc 3.2 through the aeration decompression valve 4.1, the aeration solenoid valve 4.2 and the aeration flowmeter 4.3 in sequence, for SBR denitrification device provides necessary dissolved oxygen; compressed air sequentially passes through air cleaning pressure reducing valve 4.4, air cleaning solenoid valve 4.5 and air cleaning flowmeter 4.6 to provide compressed air for ammonia nitrogen on-line electrode cleaning. The outlet water passes through the outlet water level valve 3.4, the pipeline filter 3.5 and the total outlet water electric valve 3.6 in sequence.

According to the two control methods of dissolved oxygen-ammonia nitrogen and pH-ammonia nitrogen described in the present invention, a short-range nitrification-anammox integrated SBR denitrification device is constructed. The device adopts Siemens S7-300 series PLC controller, combined with German WTW multi-parameter online electrode (DO, pH, ORP, EC and T) and Endress+Hauser ammonia nitrogen online electrode to realize short-range nitrification- Highly automated operation of anaerobic ammonium oxidation integrated SBR process. The influent is the dewatered filtrate of digested sludge from a large sewage treatment plant. The main water quality indicators are shown in Table 1. Add NH ₄ Cl and NaHCO ₃ to increase the ammonia nitrogen and alkalinity levels of the influent.

Table 1 Water quality of digested sludge dewatering filtrate (unit: mg·L ^-1 , except pH)

pH COD NH ₄ ⁺ -N NO ₃ ^- -N NO ₂ ^- -N Alkalinity 7.90±0.20 130.20±41.00 154.00±12.20 2.80±2.50 3.20±5.20 1030.40±173.30

With reference to Fig. 1, Fig. 2 and Fig. 3, the dissolved oxygen-ammonia nitrogen control method and the pH-ammonia nitrogen control method of the present invention are respectively described in detail.

1. Dissolved oxygen-ammonia nitrogen joint control mode

Add NH ₄ Cl and NaHCO ₃ to the influent to increase the concentration of ammonia nitrogen in the influent to 700.00 mg·L ^-1 . The PLC control system runs the dissolved oxygen-ammonia nitrogen control method. After starting a new cycle, the stirring paddle is started first, and then the water inlet pump is turned on to complete the water inlet of the SBR denitrification device in a short time. Then the aeration system was turned on, the aeration flow rate was adjusted, and the DO concentration in the SBR denitrification device was controlled to be 0.20-0.30 mg·L ^-1 . Under the joint action of ammonia oxidizing bacteria (AOB) and anammox bacteria, the ammonia nitrogen concentration gradually pH decreased gradually, and NO ₂ ^- -N was always kept below 8.00mg·L ^-1 . When the concentration of ammonia nitrogen gradually decreased to 30.00mg·L ^-1 , the aeration system stopped working, and the SBR denitrification device entered the stage of anoxic stirring, and DO decreased rapidly by 0.00mg·L ^-1 . The anaerobic ammonium oxidation reaction between the NO ₂ ^- -N and the remaining NH ₄ ⁺ -N continues to occur, so that the effluent water is almost free of NO ₂ ^- -N, and the generated N ₂ is fully dissipated under the action of stirring, and the sludge The settling effect is not worsened by gas generation. After the stirring stage is completed, the SBR denitrification device enters the sedimentation stage, the sludge quickly sinks to the bottom of the SBR denitrification device, and the upper liquid is clarified. The drain pump is then turned on to drain 20L of water out of the SBR. After the drainage is completed, the stirring paddle is turned on, and the SBR denitrification device enters the idle stage. After the idle stage is over, the water inlet pump is turned on again, and the SBR denitrification device starts a new cycle. Figure 4 shows the output results of four online electrodes including pH, DO, ORP, EC and ammonia nitrogen in a single cycle of the SBR denitrification device. Figure 5 shows the changes of NH ₄ ⁺ -N, NO ₃ ^- -N, NO ₂ ^- -N and TN in a single cycle. In the dissolved oxygen-ammonia nitrogen control method, the hydraulic retention time of the SBR denitrification unit is 1.59d, the influent ammonia nitrogen load is 0.44kgNH ₄ ⁺ -N·m ^-3 ·d ^-1 , the removal rate of ammonia nitrogen is 96.50%, and the total nitrogen The removal rate is as high as 93.10%, showing a high denitrification effect, and the NO ₂ ^- -N is stable below 8.00mg·L ^-1 , thus avoiding its inhibitory effect on anammox bacteria.

2. pH-ammonia nitrogen combined control mode

Add NH ₄ Cl and NaHCO ₃ to the influent to increase the concentration of ammonia nitrogen in the influent to 250.00 mg·L ^-1 . The PLC control system runs the pH-ammonia nitrogen joint control mode.

After starting a new cycle, the stirring paddle is started first, and then the water inlet pump is turned on to complete the water inlet of the SBR denitrification device in a short time. Then the aeration system was turned on, the aeration flow rate was adjusted, and the DO concentration in the SBR denitrification device was controlled to be 0.10-0.20 mg·L ^-1 . After the aeration system started, under the joint action of ammonia oxidizing bacteria (AOB) and anammox bacteria, the concentration of ammonia nitrogen gradually decreased, but at the same time, the pH also gradually decreased. Use pH fluctuations to control the start and stop of the aeration system. As shown in Figure 6, the pH drop is proportional to the accumulation of NO ₂ ^- -N in the system. The pH drop in the aeration stage is set to ΔpH1. The average concentration of NO ₂ ^- -N at the end of the system is only 4.14 mg·L ^-1 . When ΔpH1 is reached, the aeration system stops, DO drops to 0.00mg·L ^-1 in a short time, the SBR denitrification device enters the anoxic stirring stage, the short-cut nitrification reaction stops, and only the anammox reaction proceeds alone, consuming For the previously accumulated NO ₂ ^- -N, the pH will rise slightly at the same time, and the increase in pH is proportional to the consumption of NO ₂ ^- -N. The pH increase in the anoxic stirring stage is set to ΔpH2, which can ensure the accumulated NO ₂ ^- -N is consumed. When ΔpH2 is reached, the aeration system starts again, and the cycle continues until the ammonia nitrogen concentration drops to the set 30.00mg·L ^-1 retention concentration. When the ammonia nitrogen electrode detects that the ammonia nitrogen concentration in the SBR drops to 30.00mg·L ^-1 , the aeration system stops working, the SBR enters the anoxic stirring stage, and the DO drops rapidly by 0.00mg·L ^-1 . The generated NO ₂ ^- -N and the remaining NH ₄ ⁺ -N continue to undergo anaerobic ammonium oxidation reaction, so that the effluent water is almost free of NO ₂ ^- -N, and the generated N ₂ is fully dissipated under the action of stirring, and the sludge The settling effect is not worsened by gas generation. After the stirring stage is completed, the SBR denitrification device enters the sedimentation stage, the sludge quickly sinks to the bottom of the SBR denitrification device, and the upper liquid is clarified. Then the drainage pump is turned on, and 20L of water is discharged from the SBR denitrification device. After the drainage is completed, the stirring paddle is turned on, and the SBR denitrification device enters the idle stage. After the idle stage is over, the water inlet pump is turned on again, and the SBR denitrification device starts a new cycle. Figure 7 shows the results of four online electrodes including pH, DO, ORP, EC and ammonia nitrogen in a single cycle of the SBR denitrification device. It can be seen that the fluctuation of pH leads to fluctuations in the readings of other electrodes. Figure 8 shows the changes of NH ₄ ⁺ -N, NO ₃ ^- -N, NO ₂ ^- -N and TN in a single cycle. Under the combined pH-ammonia nitrogen control mode, the hydraulic retention time of the SBR denitrification unit is 1.86d, the influent ammonia nitrogen load is 0.14kgNH ₄ ⁺ -N·m ^-3 ·d ^-1 , the removal rate of ammonia nitrogen is 89.60%, and the total nitrogen The removal rate was 86.60%, showing a high denitrification effect, and the NO ₂ ^- -N was stable below 5.00mg·L ^-1 .

Claims (4)

1. the control method of short distance nitration-anaerobic ammoxidation integral type SBR denitrification process, respectively dissolved oxygen-ammonia control side Method and pH- ammonia control methods；Wherein：

Dissolved oxygen-ammonia control method is in line electrode, by dissolved oxygen in line electrode using dissolved oxygen in line electrode and ammonia nitrogen Aeration quantity is controlled, and then controls NO in SBR₂ ^-- N concentration levels, the short distance nitration and Anammox for realizing ammonia nitrogen is reacted same Synchronously carried out in one SBR, concentration is retained by ammonia nitrogen of the ammonia nitrogen in line electrode controls SBR；

PH- ammonia control methods be using pH in line electrode and ammonia nitrogen in line electrode, by pH the nitrification stage range of decrease Δ pH1 The stopping of aerating system is controlled, the amplification Δ pH2 by pH in the Anammox stage controls the unlatching of aerating system, realizes ammonia The short distance nitration of nitrogen is reacted in same SBR alternately with Anammox, passes through ammonia of the ammonia nitrogen in line electrode controls SBR Nitrogen retains concentration.

2. control method according to claim 1, wherein, whole short distance nitration-anaerobic ammoxidation integral type SBR denitrogenation works Skill is divided into water, reaction, stirring, precipitation, draining and six steps of leaving unused.

3. control method according to claim 1, wherein, dissolved oxygen concentration in dissolved oxygen-ammonia control method control SBR In 1.00mgL^-1Hereinafter, control aerobic stage NO₂ ^-- N concentration is in 10.00mgL^-1Hereinafter, control ammonia nitrogen retain concentration be 10.00~30.00mgL^-1。

4. control method according to claim 1, wherein, pH- ammonia controls method control aerobic stage NO₂ ^-- N concentration exists 10.00mg·L^-1Hereinafter, it is 10.00~30.00mgL to control ammonia nitrogen to retain concentration^-1。