A method for ammonia and oxygen synergistically enhanced partial nitrosation-anaerobic ammonia oxidation denitrification

Abstract

The application discloses a kind of ammonia oxygen synergistic enhanced partial nitrosation-anaerobic ammonia oxidation denitrification method, belong to sewage biological denitrification field, this method is completed in denitrification device, based on NH4 + -N and DO concentration dependence relationship with denitrification function microorganism, by coordinating control NH4 + -N and DO concentration, control DO concentration is: R 2 =0.9863, wherein C DO =DO concentration, NH4 + -N concentration, NH4 + -N concentration range is to achieve inhibition to NOB, more suitable in low NH4 + -N concentration sewage treatment facility application.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of biological denitrification of sewage, and particularly relates to a method for ammonia-oxygen synergistic enhanced partial nitritation-anammox denitrification. BACKGROUND

[0002] The discovery of anaerobic ammonia oxidation (Anammox) provides a new idea for biological denitrification of sewage (waste water). In recent years, denitrification processes such as partial nitritation-anammox (PN / A) and partial denitrification-anammox (PD / A) have been derived from Anammox. Among these processes, PN / A is usually selected as the preferred process due to its better performance in reducing oxygen and carbon source consumption. However, the application of this process is currently observed only in the treatment of sewage sludge digestion liquid and other wastewater containing high concentrations of ammonia nitrogen (NH4 + -N), and its application in municipal (domestic) sewage denitrification (mainstream system) is relatively limited. This is mainly because it is difficult to achieve stable accumulation of nitrite nitrogen (NO2 + -N) under the environmental conditions of low NH4 - -N and low temperature, that is, nitrite oxidizing bacteria (NOB) have a more competitive advantage and can further oxidize NO2 - -N required for Anammox bacteria reaction to nitrate nitrogen (NO3 - -N), which results in no NO2 - -N available for Anammox bacteria, seriously damaging the stability of the PN / A system. Therefore, the prerequisite for ensuring the smooth progress of PN / A denitrification is the inhibition of NOB.

[0003] To effectively inhibit the activity of NOB in the mainstream PN / A system, researchers have developed various inhibition methods, including low DO concentration limitation, batch free ammonia (FA) or free nitrite acid (FNA) inhibition, short sludge retention time (SRT) operation, and low NH4 + -N concentration, etc. However, the low DO concentration limitation strategy can only inhibit NOB-Nitrobacter with weak oxygen affinity, and has poor inhibition effect on NOB-Nitrospira with strong oxygen affinity; the batch FA or FNA inhibition strategy requires periodic placement of sludge in a solution containing high concentrations of FA or FNA, which increases the difficulty of system operation and management; short SRT operation can effectively eliminate NOB, but it will affect the enrichment of Anammox bacteria, and thus affect the stability of the denitrification system; and the low NH4 + -N concentration strategy requires maintaining a high effluent NH4 + -N concentration, which is difficult to meet the discharge requirements. Therefore, it is particularly important to study a NOB inhibition strategy with good inhibition effect and simple operation. SUMMARY

[0004] In view of this, in order to solve the technical problems in the background art, it is necessary to provide an ammonia-oxidation synergistic enhanced partial nitritation-anaerobic ammonia oxidation (PN / A) denitrification method, by establishing NH4 + -N and DO concentration dependence relationship with denitrification functional microorganisms, and determining the optimal DO concentration required when the microorganisms are in contact with different NH4 + -N concentrations, so as to effectively inhibit the proliferation of NOB and ensure that the PN / A denitrification process proceeds at the maximum rate.

[0005] To achieve the above purpose, the present application realizes the following technical solutions:

[0006] A method for ammonia-oxidation synergistic enhanced partial nitritation-anaerobic ammonia oxidation denitrification, characterized in that: the method is completed in a denitrification device, which includes a reactor, the inside of the reactor is filled with fillers, the fillers are K3 or K5, and the fillers contain denitrification functional microorganisms with a relative abundance of ≥0.01%; sewage and / or wastewater containing low-concentration NH4 + -N to be treated are continuously injected into the reactor, the hydraulic retention time in the reactor is maintained at 8-12h, so that the fillers are fully mixed with the sewage; the temperature in the reactor is controlled at room temperature, generally 20-25℃, and the DO concentration is controlled at:

[0007] R 2 is 0.9863, wherein C DO is the DO concentration, is the NH4 + -N concentration, and the NH4 + -N concentration ranges from

[0008] Preferably, the reactor operates in a continuous flow mode, the upper part of the reactor is provided with a water inlet pipe, the water inlet pipe is connected to one end of a water inlet pump, the other end of the water inlet pump extends to a sewage tank; the denitrification device further includes an aeration device, the aeration device is connected with an aeration pipe, the aeration pipe extends to the middle and lower part of the reactor; one side of the upper part of the reactor is provided with an overflow port, the overflow port is installed with a water outlet pipe; the inside of the reactor is installed with a stirring device, and the outside of the stirring device is installed with a dense water filtering cover.

[0009] Preferably, the type of the fillers is K3, the diameter is 25mm, and the specific surface area is 500-800m 2 / m 3 The denitrification functional microorganisms are nitrifying bacteria and / or anaerobic ammonia oxidation bacteria.

[0010] Preferably, the reactor is of an open structure; and the filling rate of the fillers is controlled at 15-30%.

[0011] Therefore, by adopting the technical scheme, the application has the beneficial effects:

[0012] 1、The application is based on the dependence of NH4 + -N and DO concentration on denitrifying functional microorganisms, and by coordinating the control of NH4 + -N and DO concentration, the inhibition of NOB is realized, and the application is more suitable for the wastewater treatment facilities with low NH4 + -N concentration. Compared with the strategy of controlling DO or NH4 + -N concentration alone, the application can obtain more long-term and stable inhibition effect, and ensure the smooth progress of the mainstream PN / A denitrification process. Compared with the batch FA or FNA inhibition strategy, the application is easier to realize in the municipal wastewater treatment plant, and the operation is simple.

[0013] 2、The application adopts the continuous flow mode to operate the PN / A process, and compared with the current more commonly used sequencing batch mode, the operation and management can be significantly simplified, and the actual needs of the continuous flow process upgrading and reconstruction of the municipal wastewater treatment plant can be better met.

[0014] 3、The application adopts the pure biofilm reactor, and compared with the more commonly used granular sludge or activated sludge reactor, the sludge-water separation is not needed, and the treatment process is simplified. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a schematic view of the denitrification device of the embodiment of the application;

[0016] In the figure, 1 is a reactor, 2 is a water inlet pump, 3 is a stirring device, 4 is an aeration device, 5 is a water inlet pipe, 6 is an aeration pipe, 7 is an overflow port, 8 is a water outlet pipe, 9 is a filler, 10 is a dense filter cover, and 11 is a wastewater tank. DETAILED DESCRIPTION

[0017] The technical scheme in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0018] Embodiment 1:

[0019] For example, Figure 1As shown, the present application provides a denitrification device, which comprises a reactor 1, the reactor 1 is of open structure and provides an aerobic environment; the inside of the reactor 1 is filled with fillers 9, too much fillers 9 will cause poor mixing effect and aggregation during system operation, and too little fillers will make the treatment efficiency lower, the filling rate is controlled to be 15%-30%, the filling rate is adjusted according to the abundance of microorganisms on the fillers, the abundance is high, and the filling rate of the fillers can be reduced accordingly, the fillers 9 are K3 or K5, and the fillers 9 contain denitrification functional microorganisms with a relative abundance of ≥0.01%; the reactor 1 operates in a continuous flow mode, an inlet pipe 5 is arranged at the upper part of the reactor 1, the inlet pipe 5 is connected with one end of an inlet pump 2, the other end of the inlet pump 2 extends to a sewage tank 11, sewage is provided by the sewage tank 11, the sewage tank 11 can precipitate raw water to avoid a large amount of suspended solids from entering the reactor 1; the denitrification device further comprises an aeration device 4, the aeration device 4 is connected with an aeration pipe 6, the aeration pipe 6 extends to the middle and lower part of the reactor 1, and can fully supplement oxygen to maintain a suitable DO concentration; an overflow port 7 is arranged at one side of the upper part of the reactor 1, and a water outlet pipe 8 is installed on the overflow port 7; a stirring device 3 is installed in the inside of the reactor 1, the stirring intensity can be changed by adjusting the power, the water body and the fillers 9 are fully mixed, and a dense water filtering cover 10 is installed outside the stirring device 3, which can effectively prevent the fillers from being rolled into the inside of the stirring device 3.

[0020] Example 2:

[0021] The device of Example 1 is used for sewage denitrification, and sewage and / or wastewater containing low-concentration NH4 + -N is continuously injected into the reactor 1, the hydraulic retention time in the reactor is maintained to be 8-12h, and the fillers 9 are fully mixed with the sewage; the temperature in the reactor 1 is controlled to be normal temperature, generally 20-25℃, the fillers 9 are taken from a stable running PN / A biofilm reactor and / or an aerobic zone of a municipal wastewater treatment plant, the fillers 9 are K3, the diameter is 25mm, the specific surface area is 500-800m 2 / m 3 , the filling rate of the fillers 9 is controlled to be 30%, the denitrification functional microorganisms are nitrifying bacteria and / or anaerobic ammonia oxidation bacteria; the NH4 + -N concentration range is The DO concentration is controlled to be:

[0022] In the formula, C DO is the DO concentration, is the NH4 + -N concentration.

[0023] With the continuous injection of the sewage, the water level of the reactor 1 will continuously rise, and when it exceeds the overflow height, the treated water will flow out through the overflow port 7.

[0024] NH4 + The relationship between the concentration of N and the concentration of DO was fitted by experiment. By setting different gradients of the concentration of DO, the optimal concentration of DO for N removal was determined according to the NRR removal effect of each group of experiments, and the R + The R 2 reached 0.9863, which met the accuracy requirements.

[0025] For example, when the concentration of NH4 was 20, 15, 10, 5 and 0.5 mg / L respectively, the required C DO and the corresponding maximum nitrogen removal load (NRR) fitting results are shown in Table 1.

[0026] Table 1 The relationship between the concentration of NH4 and the concentration of DO in the PN / A system DO and the corresponding NRR

[0027]

[0028] Example 3:

[0029] The device and method of Example 2 were used to remove nitrogen from wastewater containing NH4 + . The effective volume of reactor 1 was 5 L, and the HRT of reactor 1 was controlled to be 8 h by controlling the flow rate of water inlet pump 2. The temperature of reactor 1 was controlled to be 25°C. The filler 9 was taken from the laboratory's PN / A reactor which had been stably treating wastewater with a medium concentration of NH4 + . The corresponding relative proportions of Anammox, ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) were 11.57±2.34%, 1.01±0.35% and 0.94±0.45% respectively. The filling rate in reactor 1 was controlled to be 30%.

[0030] The wastewater in wastewater tank 11 had a concentration of NH4 + -N of 100 mg / L, which was continuously injected into reactor 1 by water inlet pump 2. Under the dual action of microbial consumption and reactor 1 self-dilution, the concentration of NH4 + -N in reactor 1 was maintained at 10 mg / L, and the concentration of DO was controlled to be 1.30 mg / L (in actual work, the fitted value is not easy to control, so the close value is taken, which has little effect on the results). The nitrogen components in the effluent of reactor 1 were measured every day for 100 days, and the NRR was calculated.

[0031] During the operation of reactor 1, the effluent NH4 + -N, NO2 - -N and NO3 -NH4-N concentration was 10.58±3.70, 1.78±0.54 and 14.47±1.70 mg / L, respectively, and the actual NRR reached 1206.03±56.56 mgN / m 2 The results were consistent with the ammonia-oxygen synergistic PN / A denitrification law.

[0032] Example 4:

[0033] The device and method of Example 2 were used to denitrify wastewater containing NH4 + -N. The effective volume of reactor 1 was 5 L, and the HRT of reactor 1 was controlled to be 9 h by controlling the flow of water inlet pump 2. The temperature of reactor 1 was controlled to be 25°C. The filler 9 was taken from the reactor of Example 3, and the relative proportions of Anammox, AOB and NOB were 7.89%, 1.17% and 1.58%, respectively. The filling rate was controlled to be 30%.

[0034] The NH4 + -N concentration of the wastewater in wastewater tank 11 was 100 mg / L, which was continuously injected into reactor 1 through water inlet pump 2. Under the dual action of microbial consumption and reactor 1 self-dilution, the NH4 + -N concentration in reactor 1 was maintained at 5 mg / L, and the DO concentration was controlled to be 1.00 mg / L. The nitrogen components of the effluent of reactor 1 were determined every day for 100 days, and the NRR was calculated.

[0035] During the operation of reactor 1, the NH4 + -N, NO2 - -N and NO3 - -N concentration was 4.53±3.18, 1.55±0.24 and 23.01±1.28 mg / L, respectively, and the actual NRR reached 1053.53±47.99 mgN / m 2 / d, which was close to the theoretical value, and the results were consistent with the ammonia-oxygen synergistic PN / A denitrification law.

[0036] Compared with Example 3, in this example, as the NH4 + -N concentration in reactor 1 decreased, the NRR decreased. The main reason was that the inhibitory effect of NOB decreased, and the advantage of NOB competing with Anammox for NO2 - -N increased, resulting in a decrease in NRR. The results were consistent with the change law in Table 1.

[0037] The above results show that by coordinately controlling the NH4 + -N and DO concentrations, the inhibition of NOB is achieved, and it is more suitable to be applied in wastewater treatment facilities with low NH4 + -N concentration. Compared with controlling DO or NH4 +Compared with the strategy of N concentration, the application can obtain more long-term stable inhibition effect, and ensure the smooth progress of mainstream PN / A denitrification process. Compared with the batch FA or FNA inhibition strategy, it is easier to realize in the municipal wastewater treatment plant, and the operation is simple.

[0038] To sum up, only the preferred embodiment of the application, but the scope of protection of the application is not limited to this, any skilled in the technical field according to the technical range disclosed by the application and the inventive concept of the application, equivalent replacement or change, should be covered within the scope of protection of the application.

Claims

1. A method of enhanced partial nitri fication-anaerobic ammonium oxidation denitrification, characterized by: The method is completed in a denitrification device, which comprises a reactor (1) operated in a continuous flow mode, the interior of the reactor (1) is filled with a filler (9), the filler (9) is K3 or K5, and the filler (9) contains denitrification functional microorganisms with a relative abundance of ≥0.01%; the sewage to be treated containing low-concentration NH4 + -N is continuously injected into the reactor (1), the hydraulic retention time in the reactor is maintained at 8-12 h, the filler (9) is fully mixed with the sewage; the temperature in the reactor (1) is controlled at room temperature, and the DO concentration is controlled at: wherein is the DO concentration, is the NH4 + - N concentration, the NH4 + - N concentration in the reactor (1) is maintained at a constant concentration, the constant concentration being set in the range 0 < NH4 ≤ 20 mg / L.

2. The process for enhanced partial nitrification-anaerobic ammonia oxidation denitrification as claimed in claim 1, wherein: The upper portion of the reactor (1) is provided with a water inlet pipe (5) connected with one end of a water inlet pump (2), and the other end of the water inlet pump (2) extends to a sewage tank (11); the denitrification device further comprises an aeration equipment (4) connected with an aeration pipe (6) extending to the middle and lower portion of the reactor (1); one side of the upper portion of the reactor (1) is provided with an overflow port (7) on which a water outlet pipe (8) is installed; the inside of the reactor (1) is provided with a stirring device (3) of which the outside is provided with a dense water filtering cover (10).

3. The process for enhanced partial nitrification-anaerobic ammonia oxidation denitrification as claimed in claim 2, wherein: The filler (9) is K3 type with a diameter of 25 mm and a specific surface area of 500-800 m 2 / m 3 The denitrifying functional microorganism is nitrifying bacteria and anaerobic ammonia-oxidizing bacteria.

4. The process for enhanced partial nitrification-anaerobic ammonia oxidation denitrification as claimed in claim 3, wherein: The temperature is 20-25 ℃; the reactor (1) is of an open structure; and the filling rate of the filler (9) is controlled to be 15-30%.

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