Device and method for coupling segmented drainage type shortcut nitrification, parallel anaerobic ammonia oxidation, denitrification and phosphorus removal with endogenous denitrification
Technical Field
The invention relates to a process for realizing deep nitrogen and phosphorus removal of domestic sewage by coupling sectional drainage type shortcut nitrification, parallel anaerobic ammonia oxidation, denitrification and phosphorus removal with endogenous denitrification, and belongs to the technical field of biological sewage treatment.
Background
China is a country with severe drought and water shortage, and although fresh water resource ranks the fourth world, the per-capita water resource amount is only 2300m31/4, which is world-average human. Meanwhile, with the acceleration of industrialization and urbanization processes in China, the wastewater discharge and water pollution are increasingly serious, and the water resource pollution form is still very severe. The most prominent problem is water eutrophication, the excessive N, P element discharged into water is the main cause of water eutrophication, and nitrogen and phosphorus removal is also the primary task of sewage treatment plants. As the urban sewage has the characteristic of low C/N ratio, COD is difficult to simultaneously meet the requirements of dephosphorization and denitrification. At present, chemical phosphorus removal and a traditional nitrification-denitrification nitrogen removal technology are adopted in most sewage treatment plants, even if chemical phosphorus removal is adopted, an external carbon source still needs to be added during denitrification, and the process has high aeration energy consumption and high sludge yield. Therefore, the technical innovation is carried out, and the important point is that a new nitrogen and phosphorus removal process is providedThe practical significance.
Firstly, the anaerobic ammonia oxidation (Anammox) process can directly convert ammonia nitrogen and nitrite into nitrogen under the action of anaerobic ammonia oxidizing bacteria, autotrophic nitrogen removal is carried out, an organic carbon source is saved, the sludge yield is low, and the sludge treatment cost is saved. The reaction cost of the sewage treatment plant can be greatly reduced. However, the anammox process can only denitrify and hardly removes phosphorus. However, the denitrification dephosphorization process performed under the anoxic condition can just meet the requirement of dephosphorization, and compared with the traditional dephosphorization process, the synchronous denitrification dephosphorization and dephosphorization not only reduces the requirement on carbon source, realizes one-carbon dual-purpose, but also reduces the yield of the phosphorus-rich sludge, and simultaneously, the DGAOs can utilize the stored internal carbon source for denitrification, thereby improving the total nitrogen removal efficiency. Therefore, for urban domestic sewage with low C/N ratio, the anaerobic ammonia oxidation denitrification dephosphorization is coupled with the endogenous denitrification process to synchronously remove nitrogen and phosphorus. Firstly, denitrifying phosphorus accumulating bacteria store and release an internal carbon source in an anaerobic section, denitrifying polysaccharide accumulating bacteria store the internal carbon source, anaerobic ammonia oxidizing bacteria denitrify by using ammonia nitrogen and nitrite nitrogen at an anoxic end, denitrifying phosphorus accumulating bacteria complete synchronous denitrification and dephosphorization by using nitrite nitrogen and nitrate nitrogen and phosphorus, and denitrifying polysaccharide accumulating bacteria perform denitrification by using nitrate nitrogen and nitrite nitrogen. Because the organic carbon source in the raw water is mainly used in the denitrification dephosphorization process and the denitrification is mainly performed by anaerobic ammonia oxidation autotrophic denitrification, the competition of the denitrification process and the dephosphorization process on the organic carbon source is avoided, and the deep denitrification dephosphorization of the sewage with low C/N ratio can be realized.
Disclosure of Invention
The invention provides a device and a method for coupling sectional drainage type short-cut nitrification and parallel anaerobic ammonia oxidation and denitrification dephosphorization with endogenous denitrification, which realize the combined application of the two-section type short-cut nitrification and phosphorus removal parallel anaerobic ammonia oxidation and denitrification dephosphorization and the endogenous denitrification technology to the deep nitrogen and phosphorus removal treatment of low C/N ratio municipal sewage, and solve the outstanding problems of insufficient carbon source, contradiction between sludge age of nitrified sludge and phosphorus removal sludge and the like in the nitrogen and phosphorus removal process of the traditional sewage treatment plant. The invention creatively provides a sectional drainage mode of the shortcut nitrification and dephosphorization reactor, so that the shortcut nitrification reactor provides a substrate for the anaerobic ammonia oxidation denitrification dephosphorization coupled with the endogenous denitrification reactor and has the functions of nitrogen and phosphorus removal, the advantages of the anaerobic ammonia oxidation denitrification dephosphorization and the endogenous denitrification process are fully exerted, the advanced nitrogen and phosphorus removal is carried out, the two reactors have the functions of nitrogen and phosphorus removal at the same time, the treatment load is higher, and the treatment effect is good.
The purpose of the invention is solved by the following technical scheme: a device and a method for sectional drainage type shortcut nitrification and parallel anaerobic ammonia oxidation, denitrification and phosphorus removal coupled endogenous denitrification are characterized by comprising a municipal sewage raw water tank (1), a shortcut nitrification and phosphorus removal reactor (2), an intermediate water tank (3), an anaerobic ammonia oxidation, denitrification and phosphorus removal coupled endogenous denitrification reactor (4) and an effluent water tank (5); the urban sewage raw water tank (1) is a closed tank body and is provided with an overflow pipe I (1.1) and an emptying valve I (1.2); the short-cut nitrification and dephosphorization reactor (2) is provided with a stirring device I (2.2), an air compressor I (2.3), a rotor flow meter I (2.4), an aeration disc I (2.5), a DO/pH on-line tester I (2.6), a sampling port/sludge discharge port I (2.7), a drain valve I (2.8), a drain valve II (2.9), a relay I (2.10) and a relay II (2.11); the intermediate water tank (3) is a closed tank body and is provided with an overflow pipe II (3.1) and an emptying valve II (3.2); the anaerobic ammonium oxidation denitrification dephosphorization coupling endogenous denitrification reactor (4) is provided with a stirring device II (4.3), an air compressor II (4.4), a rotor flow meter II (4.5), an aeration disc II (4.6), a DO/pH on-line tester II (4.7), a drain valve II (4.8), a sampling port/sludge discharge port II (4.9), a relay III (4.10) and an anaerobic ammonium oxidation filler (4.11); the water outlet tank (5) is a closed tank body and is provided with an overflow pipe III (5.1), an emptying valve III (5.2) and a water outlet (5.3);
the municipal sewage raw water tank (1) is connected with the short-cut nitrification and phosphorus removal reactor (2) through a water inlet pump I (2.1) and is connected with the anaerobic ammonia oxidation denitrification and phosphorus removal coupling endogenous denitrification reactor (4) through a water inlet pump II (4.1); the short-cut nitrification phosphorus removal reactor (2) is connected with the water outlet water tank (5) through a drain valve I (2.8) and a relay I (2.10), and is connected with the intermediate water tank (3) through a drain valve II (2.9) and a relay II (2.11); the intermediate water tank (3) is connected with an anaerobic ammonia oxidation denitrification dephosphorization coupling endogenous denitrification reactor (4) through a water inlet pump III (4.2); the anaerobic ammonia oxidation denitrification dephosphorization coupling endogenous denitrification reactor (4) is connected with an effluent water tank (5) through a drain valve III (4.8) and a relay III (4.10).
The method for realizing deep denitrification of domestic sewage by applying the device is characterized by comprising the following steps:
1) and (3) a system starting stage:
inoculating short-cut nitrified sludge into the short-cut nitrified phosphorus removal reactor (2) to obtain seed sludge, wherein the sludge concentration MLSS in the reactor is 2500 +/-300 mg/L; the anaerobic ammonia oxidation denitrification dephosphorization coupling endogenous denitrification reactor (4) is inoculated with denitrification dephosphorization floc sludge and denitrifying glycan bacterial floc sludge which take nitrite nitrogen and nitrate nitrogen as electron acceptors, and simultaneously, anaerobic ammonia oxidation sponge filler is added, the filling ratio is 40-50%, and the density MLSS of the floc sludge in the reactor is 2500 +/-300 mg/L.
2) And (3) an operation stage:
2.1) sewage in the raw urban sewage tank (1) enters the short-cut nitrification and dephosphorization reactor (2) through a water inlet pump I (2.1), anaerobic stirring is started while water enters, and the short-cut nitrification and dephosphorization reactor (2) is subjected to anaerobic stirring for 120-180 min; and then, aerobic aeration is carried out for 90-150 min, aeration quantity is adjusted through a gas rotameter I (2.4), DO concentration is controlled to be kept at 0.5-1.0 mg/L, precipitation and drainage are carried out for 30min after aeration and stirring are finished, the drainage ratio is 40-50%, and the drainage enters an intermediate water tank (3). And after the first drainage is finished, starting anoxic stirring for 90-150 min, and after the reaction is finished, precipitating and draining for the second time for 30min, wherein the drainage ratio is 20-40%. Standing for 30min after secondary drainage, and starting the next period;
2.2) after the drainage of the short-cut nitrification and phosphorus removal reactor (2) is finished, the sewage in the raw urban sewage tank (1) enters the anaerobic ammonia oxidation and denitrification phosphorus removal coupling endogenous denitrification reactor (4) through a water inlet pump II (4.1), anaerobic stirring is started while water is fed, the water feeding ratio is 25%, and the anaerobic stirring is carried out for 120-180 min; then, the effluent of the short-cut nitrification and phosphorus removal reactor (2) in the intermediate water tank (3) enters an anaerobic ammonia oxidation denitrification and phosphorus removal coupling endogenous denitrification reactor (4) through a water inlet pump III (4.2), and anoxic stirring is started while water enters, wherein the water inlet ratio is 50%, and the anoxic stirring is carried out for 180-240 min; and (3) draining the sediment for 30min, wherein the drainage rate is 75%, discharging the discharged water into a water outlet tank (5), standing for 30min, completing one period, and then starting the next period.
When the short-cut nitrification and phosphorus removal reactor (2) and the anaerobic ammonia oxidation and denitrification phosphorus removal coupled endogenous denitrification reactor (4) operate, sludge needs to be discharged, when the short-cut nitrification and phosphorus removal reactor (2) operates, the sludge concentration in the reactor is maintained at 2500 +/-300 mg/L, and the sludge age is controlled to be 15-25 days; the sludge concentration of the anaerobic ammonia oxidation denitrification dephosphorization coupled endogenous denitrification reactor (4) is maintained within the range of 2500 +/-300 mg/L.
The invention has the following advantages:
1) the advantages of anaerobic ammonia oxidation denitrification dephosphorization and endogenous denitrification processes are effectively combined, and nitrogen and phosphorus are synchronously removed under the condition of low C/N ratio;
2) the nitrifying bacteria, the anaerobic ammonia oxidation denitrification phosphorus accumulation bacteria and the denitrifying polysaccharide bacteria are separated, all microbial floras are in good living environment, and the anaerobic ammonia oxidation denitrification phosphorus removal coupling endogenous denitrification reactor avoids adverse effects caused by oxygen and is beneficial to efficient operation of all systems;
3) the two reactors are in a synchronous operation state, primary drainage of the short-cut nitrification and phosphorus removal reactor provides a substrate for the anaerobic ammonia oxidation denitrification phosphorus removal coupled endogenous denitrification reactor, secondary drainage denitrification remains nitrite nitrogen, the anaerobic ammonia oxidation denitrification phosphorus removal coupled endogenous denitrification reactor carries out advanced treatment, and the two reactors both have the functions of nitrogen and phosphorus removal and have high treatment load;
4) the COD of the raw water is fully utilized, the first SBR carbon source is used for removing phosphorus and denitrification after drainage, and the second reactor COD is used for removing phosphorus by denitrification, so that the low C/N sewage can be treated;
5) the device has good adaptation effect on water quality fluctuation, and avoids the influence caused by water quality change through water quantity control.
In conclusion, the method for treating the urban domestic sewage with the low C/N ratio has the advantages of high-efficiency nitrogen and phosphorus removal, low operation energy consumption, cost saving, less greenhouse gas generation, low sludge yield, stable system treatment effect and the like.
Drawings
FIG. 1 is a schematic diagram of two sectional drainage type shortcut nitrification and parallel anaerobic ammonia oxidation denitrification dephosphorization coupled endogenous denitrification processes.
In fig. 1: 1-a raw water tank of municipal sewage, 2-a short-cut nitrification and phosphorus removal reactor, 3-an intermediate water tank, 4-an anaerobic ammonia oxidation denitrification and phosphorus removal coupled endogenous denitrification reactor, and 5-an effluent water tank; 1.1-raw water tank overflow pipe I, 1.2-raw water tank emptying valve I; 2.1-a water inlet pump I2.2-stirring devices I, 2.3-air compressors I, 2.4-rotor flowmeters I, 2.5-aeration discs I, 2.6-pH and DO online measuring instruments I, 2.7 sampling ports/sludge discharge ports I, 2.8-drain valves I, 2.9-drain valves II, 2.10-relays I, 4.11-relays II; 3.1-intermediate water tank overflow pipe II, 3.2-intermediate water tank blow-down valve II; 4.1-water inlet pump II, 4.2-water inlet pump III, 4.3-stirring device II, 4.4-air compressor II, 4.5-rotor flow meter II, 4.6-aeration disc II, 4.7-pH and DO online measuring instrument II, 4.8 water discharge valve III, 4.9 sampling port/sludge discharge port II, 4.10-relay III; 5.1-overflow pipe III of water outlet tank, 5.2-blow-down valve III of water outlet tank, and 5.3 water outlet.
Detailed Description
The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples:
as shown in figure 1, the device used in the sectional drainage type partial nitrification and parallel anaerobic ammonia oxidation, denitrification and phosphorus removal coupled endogenous denitrification process comprises a municipal sewage raw water tank (1), a partial nitrification and phosphorus removal reactor (2), an intermediate water tank (3), an anaerobic ammonia oxidation, denitrification and phosphorus removal coupled endogenous denitrification reactor (4) and an effluent water tank (5); the system is characterized in that a municipal sewage raw water tank (1) is connected with a short-cut nitrification and phosphorus removal reactor (2) through a water inlet pump I (2.1) and is connected with an anaerobic ammonia oxidation denitrification phosphorus removal coupling endogenous denitrification reactor (4) through a water inlet pump II (4.1); the short-cut nitrification phosphorus removal reactor (2) is connected with the water outlet water tank (5) through a drain valve I (2.8) and a relay I (2.10), and is connected with the intermediate water tank (3) through a drain valve II (2.9) and a relay II (2.11); the intermediate water tank (3) is connected with an anaerobic ammonia oxidation denitrification dephosphorization coupling endogenous denitrification reactor (4) through a water inlet pump III (4.2); the anaerobic ammonia oxidation denitrification dephosphorization coupling endogenous denitrification reactor (4) is connected with an effluent water tank (5) through a drain valve III (4.8) and a relay III (4.10).
The experiment adopts the domestic sewage of the family district of Beijing university of industry as the raw water, and the specific water quality is as follows: the COD concentration is 166-296mg/L, NH4 +-N concentration 58-87mg/L, NO2 --N≤2mg/L,NO3 -N is less than or equal to 1.5 mg/L. The experimental system is shown in figure 1, each reactor is made of organic glass, and the total volume of the short-cut nitrification and dephosphorization reactor is 11L, wherein the effective volume is 10L; anaerobic ammonia oxidation denitrification dephosphorization is coupled with the total volume of the endogenous denitrification reactor of 12L and the effective volume of 11L.
The specific operation is as follows:
1) and (3) a system starting stage:
inoculating short-cut nitrified sludge into the short-cut nitrified phosphorus removal reactor (2) to obtain seed sludge, wherein the sludge concentration MLSS in the reactor is 2500 +/-300 mg/L; the anaerobic ammonia oxidation denitrification dephosphorization coupling endogenous denitrification reactor (4) is inoculated with denitrification dephosphorization floc sludge and denitrifying glycan bacterial floc sludge which take nitrite nitrogen and nitrate nitrogen as electron acceptors, and simultaneously, anaerobic ammonia oxidation sponge filler is added, the filling ratio is 40-50%, and the density MLSS of the floc sludge in the reactor is 2500 +/-300 mg/L.
2) And (3) an operation stage:
2.1) sewage in the raw urban sewage tank (1) enters the short-cut nitrification and dephosphorization reactor (2) through a water inlet pump I (2.1), anaerobic stirring is started while water enters, and the short-cut nitrification and dephosphorization reactor (2) is subjected to anaerobic stirring for 120-180 min; and then, aerobic aeration is carried out for 90-150 min, aeration quantity is adjusted through a gas rotameter I (2.4), DO concentration is controlled to be kept at 0.5-1.0 mg/L, precipitation and drainage are carried out for 30min after aeration and stirring are finished, the drainage ratio is 40-50%, and the drainage enters an intermediate water tank (3). And after the first drainage is finished, starting anoxic stirring for 90-150 min, and after the reaction is finished, precipitating and draining for the second time for 30min, wherein the drainage ratio is 20-40%. Standing for 30min after secondary drainage, and starting the next period;
2.2) after the drainage of the short-cut nitrification and phosphorus removal reactor (2) is finished, the sewage in the raw urban sewage tank (1) enters the anaerobic ammonia oxidation and denitrification phosphorus removal coupling endogenous denitrification reactor (4) through a water inlet pump II (4.1), anaerobic stirring is started while water is fed, the water feeding ratio is 25%, and the anaerobic stirring is carried out for 120-180 min; then, the effluent of the short-cut nitrification and phosphorus removal reactor (2) in the intermediate water tank (3) enters an anaerobic ammonia oxidation denitrification and phosphorus removal coupling endogenous denitrification reactor (4) through a water inlet pump III (4.2), and anoxic stirring is started while water enters, wherein the water inlet ratio is 50%, and the anoxic stirring is carried out for 180-240 min; and (3) draining the sediment for 30min, wherein the drainage rate is 75%, discharging the discharged water into a water outlet tank (5), standing for 30min, completing one period, and then starting the next period.
When the short-cut nitrification and phosphorus removal reactor (2) and the anaerobic ammonia oxidation and denitrification phosphorus removal coupled endogenous denitrification reactor (4) operate, sludge needs to be discharged, when the short-cut nitrification and phosphorus removal reactor (2) operates, the sludge concentration in the reactor is maintained at 2500 +/-300 mg/L, and the sludge age is controlled to be 15-25 days; the sludge concentration of the anaerobic ammonia oxidation denitrification dephosphorization coupled endogenous denitrification reactor (4) is maintained within the range of 2500 +/-300 mg/L.
The test result shows that: after the operation is stable, the COD concentration of the primary effluent of the short-cut nitrification and dephosphorization reactor (2) is 42-52 mg/L, and NH4 +-N concentration < 3mg/L, NO2 --N is 24-32 mg/L, NO3 --N < 3 mg/L; the COD concentration of the secondary drainage is 39-49 mg/L, NH4 +-N concentration < 3mg/L, NO2 --N<3mg/L,NO3 --N < 2 mg/L; COD concentration of effluent of the anaerobic ammonia oxidation denitrification dephosphorization coupled endogenous denitrification SBR reactor (4) is 36-53 mg/L, NH4 +-N concentration < 3mg/L, NO2 -N is < 2mg/L, NO3 -N < 2mg/L, TN concentration < 10mg/L, PO4 3-The concentration of-P is less than 0.5 mg/L.
The foregoing is a detailed description of the invention that will enable those skilled in the art to better understand and utilize the invention, and it is not to be limited thereby, since various modifications and changes may be made by those skilled in the art without departing from the scope of the invention.