Device and method for realizing deep denitrification of municipal domestic sewage by coupling shortcut nitrification-anaerobic ammonia oxidation denitrification
Technical Field
The invention relates to a device and a method for realizing deep denitrification of municipal domestic sewage by coupling shortcut nitrification-anaerobic ammonia oxidation denitrification, belonging to the field of sewage biological treatment and being suitable for deep denitrification of low C/N ratio municipal domestic sewage.
Background
The pollution of nitrogen and phosphorus in water bodies is caused by urban sewage, industrial wastewater, agricultural wastewater and the like which are discharged in large quantities by human activities. Wherein the nitrogen in the municipal sewage mainly exists in the form of organic nitrogen and ammonia nitrogen, which not only has great threat to human health; meanwhile, water eutrophication can be caused, the ecological environment is damaged, and water resource shortage is caused. The traditional biological treatment technology for nitrifying and denitrifying sewage has the problems of insufficient carbon source, high energy consumption and low denitrification efficiency. The discovery of anaerobic ammonia oxidation provides a new way for realizing sewage denitrification with high efficiency and energy saving. At present, sewage denitrification is mainly carried out by coupling a short-cut nitrification process and an anaerobic ammonia oxidation process, and the method has the advantages of aeration quantity saving, no need of an additional carbon source and low sludge yield.
The short-cut nitrification is realized by controlling the traditional nitrification process in the ammoxidation stage in a real-time control mode, namely, in the nitrification process, when the ammoxidation reaction is finished, H is not generated in the system any more+The pH value change curve has an inflection point of changing from descending to ascending, namely an ammonia nitrogen valley point, so that the system can be monitored in real timeThe pH value in the system changes, the aeration is stopped when the pH curve reaches the ammonia nitrogen valley point, the nitration reaction is controlled at the ammonia oxidation stage, and the substrate NO is provided for the anaerobic ammonia oxidation reaction2 --N。
In addition, a certain amount of nitrate nitrogen is generated in the anaerobic ammonia oxidation process, and the effluent sometimes does not reach the standard. The problem can be solved by introducing a certain amount of organic matters into the anaerobic ammonia oxidation reactor to construct an anaerobic ammonia oxidation coupling denitrification system. On one hand, denitrification consumes organic matters in sewage to generate CO2Providing a proper growth environment and an inorganic carbon source for the anaerobic ammonium oxidation bacteria; intermediate product NO of simultaneous denitrification process2 -N can be utilized by anaerobic ammonium oxidation bacteria in situ to react, and a substrate is provided for anaerobic ammonium oxidation reaction; on the other hand, although the organic matters do not participate in the anaerobic ammonia oxidation process, the organic matters are main substances for synthesizing anaerobic ammonia oxidation cells, the growth rate of microorganisms can be accelerated by adding a certain amount of organic matters into an anaerobic ammonia oxidation system, and research shows that the anaerobic ammonia oxidation reaction is promoted to a certain extent by adding the organic matters, the anaerobic ammonia oxidation reaction can be cooperated with denitrification reaction to remove total nitrogen in the system, the removal rate of the total nitrogen in the system is improved, and the quality of effluent water is improved.
According to the invention, part of organic matters in the domestic sewage are introduced into the anaerobic ammonia oxidation reactor to construct the anaerobic ammonia oxidation coupling denitrification system, so that the efficient utilization of the organic matters in the domestic sewage is realized, and the denitrification performance of the system is further improved; in addition, the method of combining hypoxia aeration with real-time control is adopted to realize stable short-cut nitrification, and has the advantages of low energy consumption and low treatment cost.
Disclosure of Invention
The invention provides a device and a method for realizing deep denitrification of municipal domestic sewage by coupling shortcut nitrification-anaerobic ammonia oxidation denitrification, and aims to solve the problem of insufficient carbon source in the traditional sewage treatment process and improve the quality of effluent.
The invention provides a device for realizing deep denitrification of municipal domestic sewage by coupling shortcut nitrification-anaerobic ammonia oxidation denitrification, which is characterized in that: the system is provided with a raw water tank (1), a short-cut nitrification reactor (PN-SBR) (2), a middle water tank (3) and an up-flow anaerobic ammonia oxidation coupling denitrification granular sludge reactor (SAD-UASB) (4); the raw water tank (1) is provided with a water inlet pump I (1.1) and a water inlet pump II (1.2); the short-cut nitrification reactor (2) is provided with a stirring device (2.1), a pH/DO tester (2.2), an aeration device (2.3), a gas flow meter (2.4), an air pump (2.5), a drain valve (2.6) and a mud valve (2.7); the middle water tank (3) is provided with a water inlet pump III (3.1); the upflow anaerobic ammonia oxidation coupling denitrification granular sludge reactor (4) is provided with a pH/DO tester (4.1), a temperature control device (4.2), a U-shaped water outlet pipe (4.3) and a gas collection port (4.4).
The raw water tank (1) is connected with a water inlet of the short-cut nitrification reactor (2) through a water inlet pump I (1.1); the water outlet of the process nitrification reactor ((2) is connected with the intermediate water tank (3) through a drain valve (2.6), the water inlet of the up-flow anaerobic ammonia oxidation coupling denitrification granular sludge reactor (4) is connected with the intermediate water tank (3) through a water inlet pump III (3.1) and is connected with the raw water tank through a water inlet pump II (1.2), and the water outlet of the anaerobic ammonia oxidation granular sludge reactor (4) is drained through a U-shaped water outlet pipe (4.3).
Meanwhile, the method for realizing deep denitrification of the municipal domestic sewage by coupling shortcut nitrification-anaerobic ammonia oxidation denitrification comprises the following steps:
1) starting the system:
1.1) starting up the short-cut nitrification reactor: and (3) inoculating the short-range nitrification floc sludge, controlling the sludge concentration to be 2500-3000 mg/L, the hydraulic retention time to be 4-5 h, and the sludge age to be 10-15 d. When the reactor is discharged with water NO2 -The accumulation rate of-N is more than 90%, and the effluent NH4 +And when the N concentration is less than 5mg/L, the start-up of the short-cut nitrification reactor is considered to be successful.
1.2) starting an anaerobic ammonia oxidation coupling denitrification granular sludge reactor: inoculating anaerobic ammonium oxidation granular sludge with the average grain diameter of 0.3-0.5 mm; controlling the sludge concentration to be 4000-5000 mg/L, the ascending flow velocity to be 0.5m/h, and the hydraulic retention time to be 150-160 min; the sludge is not actively discharged in the operation process; controlling the temperature in the reactor to be 30 +/-1 ℃ by a temperature control device; when reactor effluent NH4 +-N and NO2 -When the N concentration is less than 5mg/L,i.e. the reactor is considered to have been started up successfully.
2) And (3) starting the running operation after success:
1.1) domestic sewage enters the short-cut nitrification reactor through the water inlet pump I, the stirring device is started, and the residual NO in the previous period is treated by using organic matters in the domestic sewage2 --N is removed by denitrification with a reaction time of 30 min; and then starting an air pump, controlling the dissolved oxygen to be 0.3-0.5 mg/L by adjusting a gas flow meter, carrying out short-range nitration reaction, controlling the aeration time (1.5-2 h) according to the ammonia nitrogen valley point of the pH change curve which is changed from descending to ascending, closing a stirring device and the air pump when the pH change reaches the ammonia nitrogen valley point, standing and precipitating for 30-60 min, then starting a drain valve, wherein the drain ratio is 50%, and controlling the sludge age to be 10-15 d by regularly discharging sludge.
1.2) mixing raw water and sewage of an intermediate water tank in proportion through a water inlet pump II and a water inlet pump III, pumping the mixture into an anaerobic ammonia oxidation coupling denitrification reactor, and controlling inlet water NH4 +The concentration of-N is 12-15 mg/L, NO2 -The N concentration is 15-20 mg/L, and the COD concentration is 55-60 mg/L; controlling the hydraulic retention time to be 150-160 min; the sludge is not actively discharged in the operation process; the temperature in the reactor is controlled to be 30 +/-1 ℃ by a temperature control device. NH in domestic wastewater by anaerobic ammoxidation4 +N with NO produced by short-cut nitration2 -Conversion of-N to N2(ii) a The denitrifying bacteria utilize organic matters in raw water to carry out anaerobic ammonium oxidation reaction to generate NO3 -Conversion of-N to N2(ii) a The effluent overflows and is discharged through a U-shaped water outlet pipe.
Compared with the traditional nitrification and denitrification sewage treatment process, the method for realizing the deep denitrification of the urban domestic sewage by coupling the shortcut nitrification and the anaerobic ammonia oxidation with denitrification provided by the invention has the following advantages:
1) organic matters in raw water are fully utilized as a carbon source, and by-products of anaerobic ammoxidation are removed through denitrification, so that the denitrification efficiency of the system is improved, and the quality of effluent water is improved;
2) the combined real-time control of the hypoxia aeration is beneficial to the stable maintenance of the short-cut nitrification, the aeration energy consumption can be saved, and the treatment cost is reduced.
Drawings
FIG. 1 is a schematic view of the apparatus of the present invention.
1-raw water tank; 1.1-water inlet pump I; 2-denitrifying phosphorus removal-shortcut nitrification biomembrane reactor; 2.1-stirring device; 2.2-pH/DO meter; 2.3-aeration device; 2.4-gas flow meter; 2.5-air pump; 2.6-drain valve I; 2.7-drain valve II; 2.8-a mud valve I; 3-a first intermediate water tank; 3.1-water inlet pump II; 4-an anaerobic ammoxidation reactor; 4.1-pH/DO meter; 4.2-temperature control device; 4.3-drain valve III; 4.4-gas collection port; 4.5-mud valve II.
Detailed Description
The invention is described in detail with reference to the accompanying drawings and examples.
As shown in fig. 1, the device for realizing deep denitrification of municipal domestic sewage by short-cut nitrification-anaerobic ammonia oxidation coupling denitrification comprises a raw water tank (1), a short-cut nitrification reactor (PN-SBR) (2), an intermediate water tank (3) and an up-flow anaerobic ammonia oxidation coupling denitrification granular sludge reactor (SAD-UASB) (4); the raw water tank (1) is provided with a water inlet pump I (1.1) and a water inlet pump II (1.2); the short-cut nitrification reactor (2) is provided with a stirring device (2.1), a pH/DO tester (2.2), an aeration device (2.3), a gas flow meter (2.4), an air pump (2.5), a drain valve (2.6) and a mud valve (2.7); the middle water tank (3) is provided with a water inlet pump III (3.1); the upflow anaerobic ammonia oxidation coupling denitrification granular sludge reactor (4) is provided with a pH/DO tester (4.1), a temperature control device (4.2), a U-shaped water outlet pipe (4.3) and a gas collection port (4.4).
The raw water tank (1) is connected with a water inlet of the short-cut nitrification reactor (2) through a water inlet pump I (1.1); the water outlet of the process nitrification reactor ((2) is connected with the intermediate water tank (3) through a drain valve (2.6), the water inlet of the up-flow anaerobic ammonia oxidation coupling denitrification granular sludge reactor (4) is connected with the intermediate water tank (3) through a water inlet pump III (3.1) and is connected with the raw water tank through a water inlet pump II (1.2), and the water outlet of the anaerobic ammonia oxidation granular sludge reactor (4) is drained through a U-shaped water outlet pipe (4.3).
The method adopts the actual domestic sewage of a certain Beijing community as the inlet water, inspects the denitrification and carbon removal performance of the system, and specifically comprises the following operations:
1) starting the system:
1.1) starting up the short-cut nitrification reactor: and (3) inoculating the short-range nitrification floc sludge, controlling the sludge concentration to be 2500-3000 mg/L, the hydraulic retention time to be 4-5 h, and the sludge age to be 10-15 d. When the reactor is discharged with water NO2 -The accumulation rate of-N is more than 90%, and the effluent NH4 +And when the N concentration is less than 5mg/L, the start-up of the short-cut nitrification reactor is considered to be successful.
1.2) starting an anaerobic ammonia oxidation coupling denitrification granular sludge reactor: inoculating anaerobic ammonium oxidation granular sludge with the average grain diameter of 0.3-0.5 mm; controlling the sludge concentration to be 4000-5000 mg/L, the ascending flow velocity to be 0.5m/h, and the hydraulic retention time to be 150-160 min; the sludge is not actively discharged in the operation process; controlling the temperature in the reactor to be 30 +/-1 ℃ by a temperature control device; when reactor effluent NH4 +-N and NO2 -And when the N concentration is less than 5mg/L, the reactor is considered to be started successfully.
2) And (3) starting the running operation after success:
1.1) domestic sewage enters the short-cut nitrification reactor through the water inlet pump I, the stirring device is started, and the residual NO in the previous period is treated by using organic matters in the domestic sewage2 --N is removed by denitrification with a reaction time of 30 min; and then starting an air pump, controlling the dissolved oxygen to be 0.3-0.5 mg/L by adjusting a gas flow meter, carrying out short-range nitration reaction, controlling the aeration time (1.5-2 h) according to the ammonia nitrogen valley point of the pH change curve which is changed from descending to ascending, closing a stirring device and the air pump when the pH change reaches the ammonia nitrogen valley point, standing and precipitating for 30-60 min, then starting a drain valve, wherein the drain ratio is 50%, and controlling the sludge age to be 10-15 d by regularly discharging sludge.
1.2) mixing raw water and sewage of an intermediate water tank in proportion through a water inlet pump II and a water inlet pump III, pumping the mixture into an anaerobic ammonia oxidation coupling denitrification reactor, and controlling inlet water NH4 +The concentration of-N is 12-15 mg/L, NO2 -The N concentration is 15-20 mg/L, and the COD concentration is 55-60 mg/L; controlling the hydraulic retention time to150-160 min; the sludge is not actively discharged in the operation process; the temperature in the reactor is controlled to be 30 +/-1 ℃ by a temperature control device. NH in domestic wastewater by anaerobic ammoxidation4 +N with NO produced by short-cut nitration2 -Conversion of-N to N2(ii) a The denitrifying bacteria utilize organic matters in raw water to carry out anaerobic ammonium oxidation reaction to generate NO3 -Conversion of-N to N2(ii) a The effluent overflows and is discharged through a U-shaped water outlet pipe.
The effect of the run during the test was as follows: in the water supply NH4 +The concentration of the-N, COD is 47.7-63.4 mg/L and 120.4-241.3 mg/L respectively, the average C/N is 3.35, and NH of effluent water is obtained after the system is stably operated4 +The average concentrations of-N, TIN and COD are respectively 0.39, 1.58 and 38.39mg/L, which is superior to the national first-class A discharge standard, and the effluent quality is good.