Method and device for high-efficiency deep denitrification of anaerobic ammonia oxidation by pure biological membrane segmented aeration AOA-SBR (anaerobic ammonia oxidation-sequencing batch reactor) with 100% drainage ratio

Abstract

The invention provides a 100% drainage ratio pure biological membrane segmented aeration AOA-SBR anaerobic ammonia oxidation high-efficiency deep nitrogen removal method and a 100% drainage ratio pure biological membrane segmented aeration AOA-SBR anaerobic ammonia oxidation high-efficiency deep nitrogen removal device. The reactor operates in an AOA (anaerobic-aerobic-anoxic) mode, after urban domestic sewage is pumped into the SBR, an internal carbon source is stored in an anaerobic section and phosphorus is released, a nitration reaction is carried out in an aerobic section, and an endogenous denitrification / denitrification phosphorus removal and anaerobic ammonia oxidation process is carried out in an anoxic zone along with a partial short-cut nitrification anaerobic ammonia oxidation process and a synchronous short-cut nitrification and denitrification process. The anaerobic ammonia oxidation reaction is conditionally carried out on the whole process scale through segmented aeration regulation (three times of aerobic and anoxic alternation). Meanwhile, the drainage ratio is set to be 100% by means of a pure filler structure, the nitrogen and phosphorus removal load is improved, and the influence of the last period is eliminated. According to the invention, anaerobic ammonia oxidation efficient deep denitrification can be realized without strict inhibition of nitrite oxidizing bacteria, the aeration demand of sewage treatment is reduced, and the energy consumption is reduced.

Description

Technical Field

[0001] The present invention relates to a 100% drainage ratio pure biofilm segmented aeration AOA-SBR anaerobic ammonia oxidation high-efficiency deep denitrification technology and device, belonging to the field of sewage biological treatment, and suitable for deep and high-efficiency denitrification of urban domestic sewage. Background Art

[0002] With the rapid development of human activities and society, the problem of water pollution is becoming increasingly serious. Nutrients such as nitrogen and phosphorus enter natural water bodies in large quantities, leading to excessive reproduction of algae and posing a serious threat to aquatic ecosystems. In order to control eutrophication of water bodies and protect the water environment, these nutrients in wastewater must be removed efficiently. The traditional biological denitrification process converts ammonia nitrogen into nitrate nitrogen through the nitrification process, and then reduces it to nitrogen gas through denitrification to achieve nitrogen removal. However, this process is not only energy-intensive, but also requires a large amount of external carbon source, which significantly increases the operating cost of sewage treatment plants. Therefore, the development and application of new energy-saving and efficient denitrification and phosphorus removal technologies has become an urgent need to solve the problem of water pollution.

[0003] The anaerobic ammonium oxidation process can directly convert ammonia nitrogen and nitrite nitrogen into nitrogen gas. It is a pure autotrophic denitrification method and removes two nitrogen species at the same time. It is very efficient. One of the keys to its engineering application is how to continuously and stably supply these two substrates. The PN / A process combined with short-range nitrification technology (NH4+→NO2-) can save 60% of aeration and 100% of carbon source. Studies have shown that short-range nitrification can be achieved through strategies such as low dissolved oxygen, intermittent aeration, and control of ammonia nitrogen residue. In SBR, several aeration stops in a cycle of intermittent aeration require frequent start and stop of the air pump, which seriously affects the service life. The intermittent aeration is adjusted to segmented aeration, that is, only a few (such as three) aeration stops in a cycle. In this way, most of the time during the entire segmented aeration period, nitrite oxidizing bacteria will be inhibited by free ammonia, which is conducive to the realization of short-range nitrification. On this basis, sufficient substrates can be provided for anaerobic ammonium oxidation, and there is no need to strictly control the ammonia nitrogen concentration at the end of the first aerobic stage.

[0004] The anaerobic / anoxic / aerobic (AOA) mode can fully utilize the raw water carbon source in the anaerobic section and store it as an internal carbon source, and endogenous denitrification occurs in the anoxic section, which can fully utilize the raw water carbon source. The application of the traditional anoxic / anaerobic / aerobic (A2O) mode in SBR requires the nitrification liquid of the previous cycle to enter the next cycle to achieve denitrification, and the drainage ratio directly determines the upper limit of the removal rate. However, AOA is different. AOA can achieve nitrogen removal in one cycle and has the potential to increase the load by increasing the drainage ratio to 100%. Simply increasing the drainage ratio may exceed the removal capacity of the system, but if it is combined with staged aeration and anaerobic ammonia oxidation technology, the denitrification efficiency of the system can be improved. On this basis, it can be evolved into a pure membrane system and a 100% drainage ratio can be applied to greatly increase the removal load. In addition, when the effluent nitrate / nitrite concentration is high, a lower drainage ratio will have an adverse effect on the storage of the carbon source in the next cycle, and the application of a 100% drainage ratio in the present invention completely avoids such effects. In this new process, the realization of short-term nitrification and anaerobic ammonium oxidation in the aerobic stage can save aeration energy consumption, and the staged aeration does not need to strictly control the concentrations of residual ammonia nitrogen and nitrite nitrogen. The endogenous denitrification and anaerobic ammonium oxidation in the anoxic stage remove nitrogen simultaneously, realizing multi-pathway and efficient nitrogen removal in the entire process.

[0005] The present invention pumps domestic sewage into the AOA-SBR reactor, and the biofilm stores the raw water carbon source as an internal carbon source in the anaerobic section, and the polyphosphate bacteria release phosphorus anaerobically; utilizing the characteristics of segmented aeration, in the aerobic section, short-range nitrification is coupled with anaerobic ammonia oxidation and endogenous denitrification to achieve partial aerobic nitrogen removal; in the anoxic section, the biofilm uses the stored internal carbon source to drive endogenous denitrification and even denitrification and phosphorus removal, and at the same time, since the segmented aeration has sufficient ammonia nitrogen and nitrite nitrogen, anaerobic ammonia oxidation can occur to achieve denitrification, and multiple pathways of synergistic denitrification are carried out during the entire segmented aeration process, and finally the deep denitrification and phosphorus removal of mainstream urban domestic sewage is achieved. At the same time, because it is a pure membrane system, the drainage ratio can be increased to 100%, the treatment load is increased, and the treatment effect is completely unaffected by the previous cycle. The process has the advantages of low carbon source demand, low aeration energy consumption, simple operation, low operating cost, and high treatment load. Summary of the invention

[0006] The object of the present invention is to provide a technology and device for high-efficiency deep denitrification of pure biofilm segmented aeration AOA-SBR anaerobic ammonia oxidation with 100% drainage ratio. The specific method is to only add biofilm fillers with short-range nitrification, endogenous denitrification and anaerobic ammonia oxidation, raw water enters the SBR reactor, the biofilm stores the carbon source in the raw water as an internal carbon source in the anaerobic section, and releases phosphorus anaerobically at the same time, and then aeration is performed in sections, short-range nitrification coupled with anaerobic ammonia oxidation and synchronous short-range nitrification and denitrification occur in the aerobic section to remove part of the total nitrogen, the biofilm in the anoxic section uses the internal carbon source stored in the anaerobic zone to denitrify nitrite and a small amount of nitrate into nitrogen gas and denitrify and remove phosphorus, and at the same time, the remaining ammonia nitrogen and nitrite nitrogen are removed by anaerobic ammonia oxidation, and the sewage is completely discharged after the end of the last section of anoxic, and finally the deep and high-efficiency denitrification and dephosphorization of domestic sewage is achieved.

[0007] The objective of the present invention is achieved through the following technical solutions:

[0008] A method for highly efficient deep denitrification of pure biofilm segmented aeration AOA-SBR anaerobic ammonia oxidation with 100% drainage ratio, the system used comprising a raw water tank for urban domestic sewage (1), a water inlet pump (2), an SBR reactor (3), an electromagnetic ball valve (4), a water outlet tank (5), an aeration pump (6), a rotor flowmeter (7), an aeration plate (8), an agitator (9), an agitator (10), a WTW main unit (11), a pH probe (12), and a DO probe (13);

[0009] The method comprises the following steps:

[0010] 1) domestic sewage in a raw water tank (1) is transported to an SBR reactor (3) via an inlet pump (2);

[0011] 2) During the operation cycle, the agitator (9) drives the agitator (10) to mix the sewage and the biofilm filler in the reactor;

[0012] 3) intermittently starting the aeration pump (6) to supply oxygen to the reactor through the aeration disk (8), and adjusting the aeration volume through the rotor flow meter (7);

[0013] 4) Real-time monitoring of pH value and dissolved oxygen concentration during the reaction process through a pH probe (12) and a DO probe (13) connected to the WTW host (11);

[0014] 5) At the end of the operation cycle, the electromagnetic ball valve (4) is opened to completely discharge the liquid in the SBR reactor (3) into the water outlet tank (5).

[0015] In order to set the drainage ratio to 100% to increase the treatment load and prevent the residual sewage from affecting the treatment effect of the next operation cycle, only biofilm fillers are set in the SBR reactor (3); the biofilm fillers are cultured fillers with short-range nitrification, endogenous denitrification and anaerobic ammonia oxidation functions, and the filling ratio is not less than 20%.

[0016] To avoid inactivation or even falling off of the biofilm filler after complete drainage, the idle time should not exceed 60 minutes. If it must be idle for a long time, water should be added to submerge the filler until the next water inflow and then drained.

[0017] Aeration is carried out in stages with 2-4 stages, which is conducive to coupling anaerobic ammonia oxidation in the whole process to improve denitrification efficiency. The aeration time of each stage decreases, and the aeration-stop ratio can be flexibly adjusted. However, there is residual ammonia nitrogen at the end of the last stage of aeration, and the concentration ratio of ammonia nitrogen to nitrite nitrogen is between 1:1 and 1:2.

[0018] Compared with the traditional nitrification and denitrification process, the present invention has the following advantages:

[0019] 1) Make full use of the carbon source of raw water. The biofilm stores the internal carbon source in the anaerobic section and produces endogenous denitrification in the anoxic section, thus reducing the treatment cost;

[0020] 2) The residual ammonia nitrogen caused by staged aeration and the effect of anaerobic ammonium oxidation are conducive to achieving and stably maintaining short-range nitrification, saving aeration and eliminating the need to accurately control the residual ammonia nitrogen concentration at the end of the first aerobic stage;

[0021] 3) Under the staged aeration operation mode, there is sufficient ammonia nitrogen and nitrite nitrogen as substrates for anaerobic ammonium oxidation during the entire aeration and aeration process in one cycle, which can fully remove nitrogen through anaerobic ammonium oxidation;

[0022] 4) The simultaneous occurrence of endogenous denitrification and anaerobic ammonium oxidation and the 100% drainage ratio greatly increase the removal load. The 100% drainage ratio also makes the treatment effect completely unaffected by the effluent of the previous cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a 100% drainage ratio pure biofilm segmented aeration AOA-SBR anaerobic ammonia oxidation high-efficiency deep denitrification technology and device system diagram:

[0024] Figure 1 In the figure: 1—urban domestic sewage raw water tank; 2—water inlet pump; 3—SBR reactor; 4—electromagnetic ball valve; 5—water outlet tank; 6—aeration pump; 7—rotameter; 8—aeration plate; 9—agitator; 10—stirring paddle; 11—WTW main unit; 12—pH probe; 13—DO probe. DETAILED DESCRIPTION

[0025] In order to make the implementation method of the present invention clearer, the invention is further described in detail in combination with specific embodiments and with reference to the accompanying drawings. It should be noted that the following embodiments are only illustrative to help understand the core ideas and technical solutions of the present invention. The protection scope of the present invention is not limited thereto.

[0026] System startup: Inoculate the return sludge from the urban sewage treatment plant and PD / A filler in the SBR reactor (2) to make the initial suspended sludge concentration in the reactor between 2000 and 3000 mg / L, the filler filling ratio is 20%-30%, and the inoculation ratio is 5%-100%. The higher the inoculation ratio, the faster the startup. The influent is urban domestic sewage, with an influent COD of 150-250 mg / L, NH 4 + -N: 35-60mg / L, C / N is 3-4; in one operation cycle, 1-2h anaerobic, 1-2h aerobic, 2-3h anoxic, 0.5-1h aerobic, 1-2h anoxic, 0.5h aerobic and 0.5h anoxic are carried out in sequence, the initial drainage ratio is 50%, and the total hydraulic retention time is 13-22h; the changes in the content of ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, phosphorus and COD in the inlet water, the end of anaerobic, the end of the first stage of aerobic, the end of the first stage of anoxic and the outlet water are tested every day, and the filler is taken every week. An ex situ batch test was conducted to determine its nitrification and denitrification performance under the reactor operation mode. If the aerobic nitrite accumulation rate in the first stage exceeded 50%, the short-range nitrification startup was successful. With the improvement of the denitrification capacity of the pure filler, the concentration of suspended sludge can be gradually reduced. When the nitrogen removal rate of the pure filler in the batch test is equivalent to that in the reactor, the suspended sludge concentration can be reduced to 0 mg / L, and then the drainage ratio is gradually increased to 100% without affecting the nitrogen removal rate as much as possible. The startup was successful when the drainage ratio was increased to 100%.

[0027] Process operation after startup: Influent is urban domestic sewage, influent COD: 150-250mg / L, NH 4 +-N: 35-60mg / L, C / N is 3-4, and in one operation cycle, 1-2h anaerobic, 1-2h aerobic, 2-3h anoxic, 0.5-1h aerobic, 1-2h anoxic, 0.5h aerobic and 0.5h anoxic are carried out in sequence, the drainage ratio is 100%, and the total hydraulic retention time is 6.5-11h; after the domestic sewage is pumped into the SBR reactor (2), it first enters the anaerobic stage, the biofilm stores the carbon source of the raw water as the internal carbon source, and the polyphosphate bacteria release phosphorus anaerobically; followed by three-stage aeration, and before the last anoxic stage, the system will be in Ammonia nitrogen and nitrite nitrogen coexist. Therefore, the system will remove part of the total nitrogen through short-term nitrification coupled with anaerobic ammonium oxidation and synchronous short-term nitrification and denitrification in the aerobic section, and will remove part of the total nitrogen through endogenous denitrification and anaerobic ammonium oxidation in the anoxic section. If the operation is proper, denitrification and phosphorus removal can also occur to achieve phosphate removal; the ammonia nitrogen, nitrite, nitrate nitrogen and phosphorus content of the effluent from the water tank (5) are detected, and finally the effluent ammonia nitrogen is less than 1.0 mg / L, the effluent nitrite is less than 0.5 mg / L, the effluent nitrate nitrogen is less than 1.0 mg / L, and the effluent phosphorus is less than 0.1 mg / L.

[0028] It should be noted that the implementation methods not drawn or described in the drawings or the body of the specification are all forms known to ordinary technicians in the relevant technical field and are not described in detail. In addition, the above definitions of each element are not limited to the various specific structures, shapes or methods mentioned in the embodiments, and cannot be simply changed or replaced. Any modifications made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for highly efficient deep denitrification of anaerobic ammonia oxidation by pure biofilm segmented aeration AOA-SBR with 100% drainage ratio, characterized in that: The device used includes a raw water tank for urban domestic sewage (1), a water inlet pump (2), an SBR reactor (3), an electromagnetic ball valve (4), a water outlet tank (5), an aeration pump (6), a rotor flow meter (7), an aeration plate (8), an agitator (9), an agitator (10), a WTW main unit (11), a pH probe (12), and a DO probe (13); Each operation cycle includes the following steps: 1) transporting domestic sewage in a raw urban sewage tank (1) to an SBR reactor (3) via an inlet pump (2); 2) When water starts to flow in, the agitator (9) is started synchronously to drive the agitator (10) to mix the sewage and the biofilm filler in the reactor; 3) intermittently starting an aeration pump (6) to supply oxygen to the reactor through an aeration plate (8), and adjusting the aeration volume through a rotor flow meter (7); the aeration mode is segmented aeration, the number of segments is 2-4, the aeration time of the latter segment is 0.5-1h shorter than the aeration time of the former segment, and at the end of the last aeration segment, there is residual ammonia nitrogen and the mass concentration ratio of ammonia nitrogen to nitrite nitrogen is 1:1 to 1:2; 4) At the end of the operation cycle, the agitator (9) is turned off and the electromagnetic ball valve (4) is opened to completely discharge the liquid in the SBR reactor (3) into the water outlet tank (5).

2. The method according to claim 1, characterized in that The initial inoculation is 5%-100%, that is, the proportion of seed filler to the total filler is 5%-100%, and the total filler filling ratio is not less than 20%.

3. The method according to claim 1, characterized in that The idle time should not exceed 60 minutes; if it must be idle for a long time, water should be added to submerge the filler and then emptied before the next water filling.

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