Urban sewage carbon-nitrogen-phosphorus co-removal method based on biological manganese oxide

Abstract

The present application relates to the field of urban sewage treatment, and particularly relates to a kind of urban sewage carbon-nitrogen-phosphorus synergistic advanced treatment method based on biological manganese oxide.The method comprises the following steps: S1, configuring up-flow denitrification filter;S2, starting stage: using the mixed solution of actual urban sewage treatment plant's secondary effluent and secondary influent+ manganese sulfate as the influent of denitrification filter, manganese concentration is 3.0mg / L, and inoculating hydrolysis acidification bacteria, denitrifying bacteria, anaerobic ammonia oxidation bacteria and manganese oxidizing bacteria in the denitrification filter, and gradually increasing the ratio of secondary influent to secondary effluent in the mixed solution to 3%;S3, stable stage: using the mixed solution of actual urban sewage treatment plant's secondary effluent and secondary influent+ manganese sulfate as the influent of denitrification filter, manganese concentration is 3.0mg / L, hydraulic retention time is 3-4 hours, and backwashing period is 9-11 days.The present application can remove carbon-nitrogen-phosphorus in the secondary effluent of actual urban sewage treatment plant at low cost, synchronously and efficiently.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of urban sewage treatment, and particularly relates to a method for deep treatment of carbon, nitrogen and phosphorus in urban sewage based on biological manganese oxide. BACKGROUND

[0002] Carbon, nitrogen and phosphorus are important pollutants in urban sewage, and their excessive discharge will cause blackening and eutrophication of the receiving water body. In order to reduce the discharge of carbon, nitrogen and phosphorus and improve the water environment quality, a large number of urban sewage treatment plants have been built in China, and the discharge standards of carbon, nitrogen and phosphorus are becoming increasingly stringent. In the Discharge Limits of Main Water Pollutants in Urban Sewage Treatment Plants (DB 5301 / T 43-2020), the A-level discharge standards of COD, ammonia nitrogen, total nitrogen and total phosphorus are 20 mg / L, 1.0 mg / L, 5 mg / L and 0.05 mg / L respectively; in some key areas, even the Class III water standard in the Environmental Quality Standards for Surface Water (GB 3838-2002) is required, which requires that the COD, ammonia nitrogen, total nitrogen and total phosphorus are not higher than 20 mg / L, 1.0 mg / L, 1.0 mg / L and 0.05 mg / L respectively.

[0003] The secondary biochemical treatment alone in urban sewage treatment plants is difficult to make the effluent carbon, nitrogen and phosphorus meet the above standards, so the urban sewage needs to be deeply treated. The organic matter in the secondary effluent is mainly composed of refractory organic matter; the nitrogen is mainly composed of nitrate nitrogen, and there is also a small amount of organic nitrogen, ammonia nitrogen and nitrite nitrogen; the phosphorus is mainly composed of inorganic phosphorus.

[0004] Considering that biological denitrification has high efficiency, low cost and little secondary pollution, it can be widely used for deep denitrification of urban sewage. The present inventors have previously developed a technical solution in the Chinese patent with the patent name of A Method for Deep and Collaborative Denitrification of Urban Sewage Based on Improved Denitrification Filter, published as CN116282521A. In the technical solution, an improved denitrification filter is used, and the secondary effluent of the urban sewage treatment plant is used as the influent of the improved denitrification filter. The quartz sand filler in the improved denitrification filter is covered with a biofilm, which contains manganese oxidizing bacteria, denitrifying bacteria, hydrolytic acidifying bacteria and anaerobic ammonia oxidizing bacteria, and contains biological manganese oxide. The filter is used for deep treatment of urban sewage, and the average values of COD, ammonia nitrogen and total nitrogen in the effluent after treatment are 8.12 mg / L, 0.66 mg / L and 1.47 mg / L respectively, and the average removal rates are 72.40%, 90.59% and 93.38% respectively; the proportion of ammonia nitrogen to total nitrogen in the effluent is 44.90%.

[0005] Although the method in the patent with publication number CN116282521A has a high removal rate for total nitrogen and does not require an external carbon source, the total nitrogen in the effluent is not reduced to below 1 mg / L. Moreover, the removal effect of manganese is not ideal, and the effluent manganese is 0.20 mg / L (the effluent manganese is 0.20 mg / L from the paper "Advanced synergetic nitrogen removal of municipal wastewater using oxidation products of refractory organic matters in secondary effluent by biogenic manganese oxides as carbon source" published in relation to the content of the patent with publication number CN116282521A). In addition, the method has almost no removal effect on total phosphorus.

[0006] To solve the problems existing in the technical solution of the patent with publication number CN116282521A, the inventors of the present patent have developed the technical solution in the Chinese patent with publication number CN116675336A entitled "Method for deep synergistic denitrification of municipal wastewater using secondary influent to provide electron donor". In the technical solution of the patent with publication number CN116675336A, a denitrification filter is also used, but the mixture of secondary effluent and filtered secondary influent from a municipal wastewater treatment plant is used as the influent of the denitrification filter, and a biofilm containing denitrifying bacteria, hydrolytic acidifying bacteria and anaerobic ammonia oxidizing bacteria is covered on the quartz sand filler in the denitrification filter. In this method, the average value of total nitrogen in the effluent is 0.51 mg / L, and the average removal rate is 97.68%, perfectly solving the problems of the total nitrogen in the effluent not being reduced to below 1 mg / L and the introduction of manganese in the patent with publication number CN116282521A.

[0007] However, in the technical solution of the patent with publication number CN116675336A, the average values of COD and ammonia nitrogen in the effluent are 17.26 mg / L and 0.17 mg / L, respectively, and the average removal rates are 61.51% and 97.37%, respectively (from the drawings in the specification of the patent with publication number CN116282521A and the paper "Performance and mechanisms of advanced synergistic nitrogen removal using organics and NH4 +NH4+-N from secondary influent as electron donors》), resulting in the effluent COD increasing to a value close to the upper limit of the standard. Moreover, the total phosphorus of the effluent of this method is 0.69 mg / L, almost no removal (from the published paper Performance and mechanisms of advanced synergistic nitrogen removal using organics and NH4+-N from secondary influuent as electron donors》 of the patent with publication number CN116675336A), still not solving the problem of phosphorus removal. The existing conventional phosphorus removal process is coagulation sedimentation filtration: phosphates react with metal ions in the coagulant to form precipitates, and then large flocs are removed by sedimentation after coagulation, and small flocs are removed by filtration. This phosphorus removal process and even the entire carbon-nitrogen-phosphorus synergistic deep treatment process has the problems of long process flow, multiple types and large amount of chemical reagent addition, high operation cost, and easy secondary pollution.

[0008] Therefore, there is an urgent need for a municipal wastewater carbon-nitrogen-phosphorus synergistic deep treatment technology with short process flow, no need for external carbon source, low operation cost, no secondary pollution, and good carbon-nitrogen-phosphorus removal effect. SUMMARY

[0009] The technical problem to be solved by the present application is to overcome the defects of the prior art and provide a municipal wastewater carbon-nitrogen-phosphorus synergistic deep treatment method based on biological manganese oxide, which can remove carbon, nitrogen and phosphorus in the secondary effluent of an actual municipal wastewater treatment plant at low cost, synchronously and efficiently.

[0010] To solve the above technical problems, the technical scheme of the present application is: a municipal wastewater carbon-nitrogen-phosphorus synergistic deep treatment method based on biological manganese oxide, comprising:

[0011] S1, configuring an upflow denitrification filter;

[0012] S2, starting phase:

[0013] The mixture of the secondary effluent and the secondary influent of an actual municipal wastewater treatment plant is used as the influent of the denitrification filter, and manganese sulfate is added to the mixture, with a manganese concentration of 3.0 mg / L; and the denitrification filter is inoculated with hydrolysis acidification bacteria, denitrifying bacteria, anaerobic ammonia oxidation bacteria and manganese oxidizing bacteria, and the ratio of the secondary influent to the secondary effluent in the mixture is gradually increased to 3%; wherein,

[0014] When gradually increasing the ratio of secondary influent to secondary effluent in the mixed liquor, wait until the effluent COD, ammonia nitrogen, total nitrogen, total phosphorus, and manganese concentrations are stable before the next increase;

[0015] Hydrolytic acidifying bacteria and denitrifying bacteria were inoculated once every 5 days, for a total of 4 times; manganese oxidizing bacteria were inoculated once every 7 days, for a total of 5 times; anaerobic ammonia oxidizing bacteria were inoculated once every 7 days, until the effluent COD, ammonia nitrogen, total nitrogen, total phosphorus and manganese concentrations were finally stable;

[0016] S3, stable phase:

[0017] The mixed liquor of the secondary effluent and the secondary influent of an actual urban sewage treatment plant was used as the influent of the denitrification filter. Manganese sulfate was added to the mixed liquor with a manganese concentration of 3.0 mg / L. The ratio of the secondary influent to the secondary effluent in the mixed liquor was 3%. The hydraulic retention time was 3 to 4 hours, and the backwash cycle was 9 to 11 days.

[0018] Furthermore, in S1, the denitrification filter tank comprises, from bottom to top, an inlet layer, a supporting layer, a filler layer, and an outlet layer; the inlet layer is provided with an inlet; the supporting layer and the filler layer are quartz sand respectively, and the particle size of the quartz sand of the supporting layer is larger than the particle size of the quartz sand of the filler layer; the outlet layer is provided with an outlet.

[0019] Furthermore, in S1, the thickness of the supporting layer is 10 cm, and the particle size of the quartz sand is 1 to 2 cm; the thickness of the filler layer is 60 cm, and the particle size of the quartz sand is 2 to 4 mm.

[0020] Furthermore, in S2, at the initial stage of the startup phase, the ratio of the secondary inlet water to the secondary outlet water in the mixed liquor is 1%.

[0021] Furthermore, in S2, for each bacteria, 200 mL of bacterial solution was inoculated each time, and the bacterial solution concentrations of hydrolytic acidifying bacteria, denitrifying bacteria, anaerobic ammonia oxidizing bacteria, and manganese oxidizing bacteria were 5 g / L to 8 g / L, 5 g / L to 6 g / L, 3 g / L to 4 g / L, and 3 g / L to 4 g / L, respectively.

[0022] Furthermore, in S2, the effluent COD, ammonia nitrogen, total nitrogen, total phosphorus, and manganese concentrations are stable, which means that the effluent COD, ammonia nitrogen, total nitrogen, total phosphorus, and manganese concentrations fluctuate by no more than 10% relative to the average concentrations of COD, ammonia nitrogen, total nitrogen, total phosphorus, and manganese within 13 to 15 consecutive days.

[0023] Furthermore, in S3, each backwashing time is 3 to 5 minutes, and the backwashing intensity is 10 to 12 L / (s·m 2 ).

[0024] After adopting the above technical solution, the present invention has the following beneficial effects:

[0025] (1) The removal efficiency of ammonia nitrogen is extremely high: the effluent ammonia nitrogen is reduced to 0.024 mg / L, and the removal rate reaches 99.24%. The anaerobic ammonia oxidation bacteria cultivated and domesticated in the denitrification filter of the application are more efficient, and they are in a dominant position when competing with denitrifying bacteria for nitrite nitrogen, and will preferentially use nitrite nitrogen as an electron acceptor to oxidize ammonia nitrogen to nitrogen, so they can almost completely remove ammonia nitrogen. In addition, the high-efficiency anaerobic ammonia oxidation bacteria can remove very low concentrations of ammonia nitrogen. In the technical solution of the patent with publication number CN116282521A, the effluent ammonia nitrogen is reduced to 0.60-0.71 mg / L; in the technical solution of the patent with publication number CN116675336A, the effluent ammonia nitrogen is reduced to 0.17 mg / L (from the paper "Performance and mechanisms of advanced synergistic nitrogen removal using organics and NH4 + -N from secondary influentas electron donors》 published in relation to the patent with publication number CN116675336A). The effluent ammonia nitrogen of the application is significantly lower than that in the solutions of the above two patents.

[0026] (2) The removal efficiency of total phosphorus is extremely high: the average effluent total phosphorus is reduced to 0.014 mg / L, and the removal rate reaches 95.15%. The denitrification filter developed in the application has the ability to enhance chemical phosphorus removal, because the effluent total phosphorus is 0.068 mg / L when the same influent is reacted in a beaker, which is higher than the Class III water standard in the "Surface Water Environmental Quality Standard" (GB 3838-2002).

[0027] (3) Manganese is efficiently removed: the effluent manganese is reduced to 0.077 mg / L, and the removal rate reaches 97.45%. The denitrification filter developed in the application enhances the ability to remove manganese, and the effluent manganese is significantly reduced. The effluent manganese concentration in the solution of the patent with publication number CN116282521A is 0.2 mg / L, and the effluent manganese is significantly reduced.

[0028] (4) Achieved efficient removal of COD: The hydrolytic bacteria cultivated and domesticated by the present application is more efficient, and when there are a large amount of easily degradable organic matter in the influent, the effluent COD can be reduced to 7.80 mg / L. Although the patent with publication number CN116282521A also reduces the effluent COD to 8.2 mg / L, the influent of its improved denitrification filter is secondary effluent, which mainly contains refractory organic matter. At this time, it is easy to cultivate hydrolytic bacteria, but the ability to remove COD is not as good as the present application. The patent with publication number CN116675336A uses a mixture of secondary effluent and secondary influent as the influent, and the influent COD is 45 mg / L, and the average effluent COD is 17.26 mg / L. When there are easily degradable organic matter, the easily degradable organic matter will be preferentially removed, which will inhibit the growth of hydrolytic bacteria that remove refractory organic matter, and the hydrolysis effect is not ideal, so the effluent COD is about 17.26 mg / L. The patent with publication number CN116675336A has a lower influent COD than the present application, indicating that the present application has more easily degradable organic matter in the influent. However, the effluent COD is higher than that of the present application. Through comparison, it is fully demonstrated that the hydrolytic bacteria cultivated and domesticated by the present application are more efficient, and can still efficiently remove COD when there are a large amount of easily degradable organic matter.

[0029] (5) Achieved simultaneous, efficient and synergistic removal of carbon, nitrogen and phosphorus: The present application can simultaneously reduce COD, ammonia nitrogen, total nitrogen and total phosphorus in one reactor to below the Class III water quality standard in the "Surface Water Environmental Quality Standard" (GB 3838-2002).

[0030] (6) Low operating cost: The present application only needs to add about 3.0 mg / L of manganese, and according to the market price of 3000 yuan / t of manganese sulfate, the operating cost is only about 0.02 yuan / t of municipal wastewater.

[0031] (7) No secondary pollution: The present application only needs to add manganese, and the generated biological manganese oxide will tightly adhere to the filler and will not flow out with the effluent. The effluent manganese is lower than 0.1 mg / L, meeting the "Drinking Water Health Standards" (GB 5749-2022).

[0032] In conclusion, the present application effectively solves the problems of long process flow, multiple types and large amount of chemical reagent addition, high operation cost, easy secondary pollution and unsatisfactory carbon, nitrogen and phosphorus removal effect in the carbon, nitrogen and phosphorus synergic advanced treatment process of municipal sewage, and realizes low-cost, synchronous, efficient and synergic removal of carbon, nitrogen and phosphorus. The secondary effluent of the municipal sewage treatment plant after the denitrification filter treatment can be reduced from the first level B standard in the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002) to the III standard in the Environmental Quality Standard for Surface Water (GB 3838-2002), and has high application value and is conducive to popularization and application. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 A flow chart of the carbon, nitrogen and phosphorus synergic advanced treatment method of municipal sewage based on biological manganese oxide of the present application;

[0034] Figure 2 A structural diagram of the treatment system configured by the present application;

[0035] Figure 3 A removal effect diagram of COD with the progress of treatment in the embodiment of the present application;

[0036] Figure 4 A removal effect diagram of nitrate nitrogen with the progress of treatment in the embodiment of the present application;

[0037] Figure 5 A removal effect diagram of ammonia nitrogen with the progress of treatment in the embodiment of the present application;

[0038] Figure 6 A removal effect diagram of nitrite nitrogen with the progress of treatment in the embodiment of the present application;

[0039] Figure 7 A removal effect diagram of total nitrogen with the progress of treatment in the embodiment of the present application;

[0040] Figure 8 A removal effect diagram of total phosphorus with the progress of treatment in the embodiment of the present application;

[0041] Figure 9 A removal effect diagram of manganese with the progress of treatment in the embodiment of the present application;

[0042] In the figure, 1, denitrification filter; 11, water inlet layer; 12, supporting layer; 13, filler layer; 14, water outlet layer; 15, water inlet; 16, water outlet; 2, pump; 3, water tank; 4, water inlet valve; 5, backwashing valve. DETAILED DESCRIPTION

[0043] In order to make the content of the present application more easily understood, the present application is further described in detail below according to specific embodiments and in combination with the drawings.

[0044] As shown in Figure 1 A kind of urban sewage carbon nitrogen phosphorus synergic advanced treatment method based on biological manganese oxide includes:

[0045] S1, the denitrification filter 1 of upflow is configured;

[0046] Specifically, the denitrification filter 1 configured is sequentially from bottom to top for water inlet layer 11, support layer 12, filler layer 13 and water outlet layer 14;Water inlet layer 14 is provided with water inlet 15;Support layer 12 and filler layer 13 are quartz sand respectively, and the particle size of the quartz sand of support layer 12 is greater than the particle size of the quartz sand of filler layer 13;Water outlet layer 14 is provided with water outlet 16.Support layer 12 is 10 cm thick, and the particle size of the quartz sand thereof is 1-2 cm;Filler layer 13 is 60 cm thick, and the particle size of the quartz sand thereof is 2-4 mm.

[0047] S2, start-up stage:

[0048] The mixture of secondary effluent and secondary influent of actual urban sewage treatment plant is used as the influent of the denitrification filter 1, and manganese sulfate is added in the mixture, and the manganese concentration is 3.0 mg / L;And the denitrification filter 1 is inoculated with hydrolytic acidification bacteria, denitrifying bacteria, anaerobic ammonia oxidation bacteria and manganese oxidizing bacteria, and the ratio of secondary influent to secondary effluent in the mixture is gradually increased to 3%;Among them,

[0049] During the process of gradually increasing the ratio of secondary influent to secondary effluent in the mixture, the next time is raised after the effluent COD, ammonia nitrogen, total nitrogen, total phosphorus and manganese concentration are stable;

[0050] Hydrolytic acidification bacteria and denitrifying bacteria are inoculated once every 5 days, a total of 4 times;Manganese oxidizing bacteria are inoculated once every 7 days, a total of 5 times;Anaerobic ammonia oxidation bacteria are inoculated once every 7 days, and inoculation is performed until the last time the effluent COD, ammonia nitrogen, total nitrogen, total phosphorus and manganese concentration are stable;

[0051] The stability of effluent COD, ammonia nitrogen, total nitrogen, total phosphorus and manganese concentration means that the COD, ammonia nitrogen, total nitrogen, total phosphorus and manganese concentration in the effluent fluctuate by no more than 10% relative to the average concentration of COD, ammonia nitrogen, total nitrogen, total phosphorus and manganese within 13-15 consecutive days.

[0052] In this step, for each kind of bacteria, 200 mL of bacterial solution is inoculated each time, and the bacterial solution concentrations of hydrolytic acidification bacteria, denitrifying bacteria, anaerobic ammonia oxidation bacteria and manganese oxidizing bacteria are 5 g / L-8 g / L, 5 g / L-6 g / L, 3 g / L-4 g / L and 3 g / L-4 g / L respectively.

[0053] In this step, initially, the secondary influent / secondary effluent is 1%, at this time the ammonia nitrogen of the influent is about 1.0 mg / L. After the secondary influent / secondary effluent is increased to 3%, the ammonia nitrogen of the influent is increased to about 3.2 mg / L. The ratio of the secondary influent to the secondary effluent in the mixed liquid is gradually increased, and the ammonia nitrogen concentration is used as the reference, and each time it is increased by 0.2-0.3 mg / L.

[0054] S3, stable stage:

[0055] The mixed liquid of the secondary effluent and the secondary influent of an actual municipal wastewater treatment plant is used as the influent of the denitrification filter, and manganese sulfate is added in the mixed liquid, and the manganese concentration is 3.0 mg / L; the ratio of the secondary influent to the secondary effluent in the mixed liquid is 3%; the hydraulic retention time is 3-4 hours, the backwashing period is 9-11 days; the time of each backwashing is 3-5 minutes; the backwashing intensity is 10-12 L / (s.m 2 ).

[0056] Figure 2 The structure diagram of the treatment system is shown in Figure 2 , the treatment system comprises a denitrification filter 1, a pump 2, a water tank 3, an influent pipe and a backwashing pipe, the water tank 3 is communicated with the influent port of the denitrification filter 1 through the influent pipe, the pump 2 is connected in series on the influent pipe to provide the liquid feeding power, the influent pipe is further provided with an influent valve 4, and the opening of the influent valve 4 is adjustable. The backwashing pipe is also communicated with the influent port 15 of the denitrification filter 1, and the backwashing pipe is provided with a backwashing valve 5, and the opening of the backwashing valve 5 is also adjustable.

[0057] Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9The removal effect diagrams of COD, nitrate nitrogen, ammonia nitrogen, nitrite nitrogen, total nitrogen, total phosphorus and manganese along with the treatment process are shown in the following table. The concentrations of COD, nitrate nitrogen, ammonia nitrogen, nitrite nitrogen, total nitrogen, total phosphorus and manganese are reduced from about 50 mg / L, 17 mg / L, 3.2 mg / L, 0.17 mg / L, 22 mg / L, 0.3 mg / L and 3.0 mg / L to 7.66-8.05 mg / L, 0.47-0.57 mg / L, 0.021-0.032 mg / L, 0.010-0.013 mg / L, 0.60-0.69 mg / L, 0.013-0.014 mg / L and 0.076-0.080 mg / L, respectively. The removal rates of COD, nitrate nitrogen, ammonia nitrogen, nitrite nitrogen, total nitrogen, total phosphorus and manganese are 84.14%-85.02%, 96.67%-97.26%, 99.00%-99.35%, 92.72%-93.93%, 96.91%-97.30%, 95.08%-95.31% and 97.36%-97.49%, respectively. The average concentrations of COD, nitrate nitrogen, ammonia nitrogen, nitrite nitrogen, total nitrogen, total phosphorus and manganese are 7.80 mg / L, 0.51 mg / L, 0.024 mg / L, 0.011 mg / L, 0.63 mg / L, 0.014 mg / L and 0.077 mg / L, respectively. The average removal rates of COD, nitrate nitrogen, ammonia nitrogen, nitrite nitrogen, total nitrogen, total phosphorus and manganese are 84.72%, 97.02%, 99.24%, 93.60%, 97.17%, 95.15% and 97.45%, respectively. The concentrations of COD, ammonia nitrogen, total nitrogen and total phosphorus in the effluent meet the Class III water quality standard in the “Environmental Quality Standards for Surface Water” (GB 3838-2002). The concentration of manganese in the effluent meets the “Drinking Water Health Standards” (GB 5749-2022).

[0058] The specific values are shown in the following table.

[0059]

[0060] In this embodiment, the period from day 0 to day 198 is the start-up phase, and the period from day 199 onwards is the stable phase. The above data are for the period from day 199 to day 211.

[0061] The method involved in the above embodiment is described in detail from the principle aspect as follows.

[0062] The organic matter in the secondary effluent of a municipal wastewater treatment plant is not removed in the secondary biochemical treatment process in the municipal wastewater treatment plant, and is refractory organic matter. The main form of nitrogen in the secondary effluent is nitrate nitrogen, and a certain amount of organic nitrogen (such as protein and microorganisms), ammonia nitrogen and nitrite nitrogen are also contained. The phosphorus in the secondary effluent is mainly inorganic phosphorus (phosphate).

[0063] The secondary influent of the municipal sewage treatment plant is treated by secondary biochemical treatment, and becomes secondary effluent, so the organic matter in the secondary influent includes not only the easily degradable organic matter removed in the secondary biochemical treatment process of the municipal sewage treatment plant, but also the refractory organic matter remaining in the secondary effluent.

[0064] In the start-up process, the filter material surface of the denitrification filter 1 gradually generates a biofilm, which includes biological manganese oxide, manganese-oxidizing bacteria, hydrolytic bacteria and anaerobic ammonia-oxidizing bacteria. In the denitrification filter 1, the biological manganese oxide and the hydrolytic bacteria can convert the refractory organic matter into the easily degradable organic matter in the presence of the easily degradable organic matter (from the secondary influent), and the organic nitrogen and the organic phosphorus are converted into ammonia nitrogen and phosphate, respectively. The inoculated denitrifying bacteria use the oxidation and hydrolysis products of the easily degradable organic matter and the refractory organic matter in the secondary influent as carbon sources to reduce the nitrate nitrogen in the secondary effluent to nitrite nitrogen, the inoculated anaerobic ammonia-oxidizing bacteria use the produced ammonia nitrogen and the ammonia nitrogen in the influent as electron donors to reduce the produced nitrite nitrogen to nitrogen, and the remaining nitrite nitrogen is further reduced to nitrogen by the denitrifying bacteria, so that the removal of carbon and nitrogen is achieved.

[0065] The manganese in the influent and the manganese produced by the reduction of the biological manganese oxide can remove the phosphate by chemical phosphorus removal. Specifically, the phosphate is first adsorbed by the microorganisms and the biological manganese oxide attached to the surface of the filler, and at the same time, the manganese is also adsorbed by the microorganisms and the biological manganese oxide, and after being adsorbed on the filler, a local high concentration of phosphate and manganese is formed, which is beneficial to the removal of phosphorus. In addition, the filler used in the present application has a small particle size of 2-4 mm, and has a large specific surface area, so the filler surface is more easily attached to irregular microorganisms and biological manganese oxide, which is beneficial to improving the adsorption capacity of the phosphate and manganese and achieving the removal of the phosphate and manganese. Furthermore, the phosphate is adsorbed multiple times by the denitrification filter layer, which can ensure the phosphorus removal effect, and the growth of the microorganisms in the filter layer close to the effluent also absorbs the phosphorus to synthesize cells, further reducing the concentration of phosphorus. Therefore, the denitrification filter 1 of the present application has the ability to strengthen chemical phosphorus removal, and the whole treatment method can achieve efficient removal of phosphorus. The reason why the phosphorus and manganese removal effects are improved in the present application compared with the patent with the publication number CN116282521A is that:

[0066] In the present application, the secondary effluent is mixed with the secondary influent to serve as the influent of the denitrification filter, and the dissolved oxygen concentration of the influent is about 2.5 mg / L, and the manganese concentration of the influent is about 3.0 mg / L. 2+ Theoretically, 0.29 mg of dissolved oxygen is required to oxidize 1 mg of Mn 2+All oxidation to biological manganese oxide (sufficient dissolved oxygen in the influent), and the oxidized biological manganese oxide will be attached to the filler in the form of small particles, increasing the specific surface area of the filler, which is beneficial to the adsorption of phosphate and manganese. Biological manganese oxide has strong adsorption capacity for manganese, so it is beneficial to the removal of manganese.

[0067] In the patent with publication number CN116282521A, secondary effluent is used as the influent of the denitrification filter, the dissolved oxygen concentration of which is about 0.5 mg / L, and the manganese sulfate concentration of which is about 0.5 mg / L. The dissolved oxygen in the influent is used for the oxidation of manganese, organic matter and ammonia nitrogen, which results in insufficient dissolved oxygen in the influent to oxidize all the manganese in the influent, so the amount of biological manganese oxide generated is small, which is not conducive to its adsorption of phosphorus and manganese, resulting in limited removal effect of phosphorus.

[0068] In addition, the present application can use secondary effluent with different carbon-nitrogen ratios (COD / TN) to provide electron donors for advanced denitrification, and by adjusting the contribution rate of short-range denitrification-anaerobic ammonia oxidation and denitrification to total nitrogen removal to adapt to secondary effluent with different carbon-nitrogen ratios, efficient and low-cost removal of total nitrogen can be achieved. For example, when the carbon-nitrogen ratio in the secondary effluent is high, the contribution rate of denitrification to total nitrogen can be increased to achieve efficient and low-cost removal of total nitrogen; when the carbon-nitrogen ratio in the secondary effluent is low, the contribution rate of short-range denitrification-anaerobic ammonia oxidation to total nitrogen can be increased to achieve efficient and low-cost removal of total nitrogen. The present application is also suitable for treating secondary effluent with different total nitrogen concentrations, because there is sufficient organic matter and ammonia nitrogen in the secondary effluent to provide electron donors for advanced denitrification.

[0069] Based on the above ideal embodiments according to the present application, through the above description, relevant personnel can make various changes and modifications without deviating from the technical idea of the present application. The technical scope of the present application is not limited to the contents of the specification, and must be determined by the scope of the claims.

Claims

1. A method for carbon, nitrogen and phosphorus synergistic advanced treatment of municipal wastewater based on biological manganese oxide, comprising: S1, configuring an upflow denitrification filter; S2, starting stage: using the mixture of secondary effluent and secondary influent of an actual municipal wastewater treatment plant as the influent of the denitrification filter, adding manganese sulfate in the mixture with a manganese concentration of 3.0 mg / L; inoculating hydrolytic acidification bacteria, denitrifying bacteria, anaerobic ammonia oxidation bacteria and manganese oxidizing bacteria in the denitrification filter, and gradually increasing the ratio of secondary influent to secondary effluent in the mixture to 3%; wherein, during the gradual increase of the ratio of secondary influent to secondary effluent in the mixture, the ratio is increased again after the COD, ammonia nitrogen, total nitrogen, total phosphorus and manganese concentration in the effluent are stable; the hydrolytic acidification bacteria and the denitrifying bacteria are inoculated every 5 days for a total of 4 times; the manganese oxidizing bacteria are inoculated every 7 days for a total of 5 times; the anaerobic ammonia oxidation bacteria are inoculated every 7 days until the COD, ammonia nitrogen, total nitrogen, total phosphorus and manganese concentration in the effluent are stable for the last time; S3, stable stage: using the mixture of secondary effluent and secondary influent of an actual municipal wastewater treatment plant as the influent of the denitrification filter, adding manganese sulfate in the mixture with a manganese concentration of 3.0 mg / L; the ratio of secondary influent to secondary effluent in the mixture is 3%; the hydraulic retention time is 3-4 hours, and the backwashing period is 9-11 days. 2.The method for carbon, nitrogen and phosphorus synergistic advanced treatment of municipal wastewater based on biological manganese oxide according to claim 1, wherein, in S1, the denitrification filter has, from bottom to top, an influent layer, a supporting layer, a filler layer and an effluent layer; the influent layer is provided with an influent port; the supporting layer and the filler layer are both quartz sand, and the particle size of the quartz sand in the supporting layer is larger than that in the filler layer; and the effluent layer is provided with an effluent port. 3.The method for carbon, nitrogen and phosphorus synergistic advanced treatment of municipal wastewater based on biological manganese oxide according to claim 2, wherein, in S1, the thickness of the supporting layer is 10 cm, and the particle size of the quartz sand therein is 1-2 cm; and the thickness of the filler layer is 60 cm, and the particle size of the quartz sand therein is 2-4 mm. 4.The method for carbon, nitrogen and phosphorus synergistic advanced treatment of municipal wastewater based on biological manganese oxide according to claim 1, wherein, in S2, in the early stage of the starting stage, the ratio of secondary influent to secondary effluent in the mixture is 1%. 5.The method for carbon, nitrogen and phosphorus synergistic advanced treatment of municipal wastewater based on biological manganese oxide according to claim 1, wherein, in S2, for each kind of bacteria, 200 mL of bacterial liquid is inoculated each time, and the bacterial liquid concentrations of the hydrolytic acidification bacteria, the denitrifying bacteria, the anaerobic ammonia oxidation bacteria and the manganese oxidizing bacteria are 5 g / L-8 g / L, 5 g / L-6 g / L, 3 g / L-4 g / L and 3 g / L-4 g / L, respectively. 6.The method for carbon, nitrogen and phosphorus synergistic advanced treatment of municipal wastewater based on biological manganese oxide according to claim 1, wherein, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ In S2, the effluent COD, ammonia nitrogen, total nitrogen, total phosphorus and manganese concentration is stable, which means that the effluent COD, ammonia nitrogen, total nitrogen, total phosphorus and manganese concentration fluctuates within 10% of the average concentration of COD, ammonia nitrogen, total nitrogen, total phosphorus and manganese within 13-15 consecutive days.

7. The biological manganese oxide-based advanced treatment method for municipal wastewater carbon, nitrogen and phosphorus synergy according to claim 1, characterized in that, In S3, the backwashing time is 3-5 minutes and the backwashing intensity is 10-12 L / (s.m 2 ).

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