Urban sewage carbon-nitrogen-phosphorus synergistic deep treatment method based on biological manganese oxide

Abstract

The present invention relates to the field of urban sewage treatment, and particularly relates to an urban sewage carbon-nitrogen-phosphorus synergistic deep treatment method based on a biological manganese oxide. The method comprises: S1, configuring an upward flow denitrification filter tank; S2, a starting stage, involving: taking a mixed solution of a secondary effluent and a secondary influent of an actual urban sewage treatment plant and manganese sulfate as the influent of the denitrification filter tank, with the manganese concentration being 3.0 mg / L, inoculating hydrolytic acidification bacteria, denitrifying bacteria, anaerobic ammonium oxidation bacteria and manganese oxidation bacteria into the denitrification filter tank, and gradually increasing the ratio value of the secondary influent to the secondary effluent in the mixed solution to 3%; and S3, a stable stage, involving: taking a mixed solution of the secondary effluent and the secondary influent of the actual urban sewage treatment plant and manganese sulfate as the influent of the denitrification filter tank, wherein the manganese concentration is 3.0 mg / L, the hydraulic retention time is 3-4 hours, and the backwashing period is 9-11 days. The present invention can synchronously and efficiently remove carbon, nitrogen and phosphorus from the secondary effluent of an actual urban sewage treatment plant at a low cost.

Description

A synergistic deep treatment method for carbon, nitrogen and phosphorus in urban sewage based on biological manganese oxide Technical Field

[0001] The present invention relates to the field of urban sewage treatment, and in particular to a method for the coordinated deep treatment of carbon, nitrogen and phosphorus in urban sewage based on biological manganese oxide. Background Art

[0002] Carbon, nitrogen, and phosphorus are important pollutants in urban sewage. Excessive discharge can lead to black, odorous, and eutrophication of receiving water bodies. To reduce their emissions and improve water quality, my country has built numerous urban sewage treatment plants. Emission standards for these pollutants are becoming increasingly stringent. For example, the "Discharge Limits of Major Water Pollutants from Urban Wastewater Treatment Plants" (DB 5301 / T 43-2020) stipulates that Class A discharge standards for 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. Some key areas even require compliance with the Class III water standards in the "Environmental Quality Standards for Surface Water" (GB 3838-2002), which stipulate that COD, ammonia nitrogen, total nitrogen, and total phosphorus should not exceed 20 mg / L, 1.0 mg / L, 1.0 mg / L, and 0.05 mg / L, respectively.

[0003] It's difficult for urban wastewater treatment plants to achieve these standards for carbon, nitrogen, and phosphorus in their effluent using only secondary biological treatment. Therefore, urban wastewater requires advanced treatment. The organic matter in secondary effluent is primarily recalcitrant; the nitrogen is primarily nitrate, with small amounts of organic nitrogen, ammonia nitrogen, and nitrite nitrogen also present; and the phosphorus is primarily inorganic.

[0004] Considering that biological denitrification is widely used for deep denitrification of urban sewage due to its high efficiency, low cost, and low secondary pollution, the inventors of this patent previously developed the technical solution disclosed in Chinese patent publication number CN116282521A, entitled "A Method for Deep Synergistic Denitrification of Urban Sewage Based on an Improved Denitrification Filter." In this technical solution, a modified denitrification filter is used, and the secondary effluent from the urban sewage treatment plant is used as the inlet water of the modified denitrification filter. The quartz sand filler of the modified denitrification filter is covered with a biofilm, which contains manganese oxidizing bacteria, denitrifying bacteria, hydrolytic acidifying bacteria and anaerobic ammonia oxidizing bacteria, as well as biological manganese oxides. The filter is used to deeply treat urban sewage. The average COD, ammonia nitrogen and total nitrogen values ​​of the treated effluent 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 in the effluent to the total nitrogen 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 does not drop below 1 mg / L. In addition, the removal effect on manganese is less than ideal, with the effluent manganese being 0.20 mg / L (the effluent manganese being 0.20 mg / L is 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 for the patent with publication number CN116282521A). In addition, the method has almost no removal effect on total phosphorus.

[0006] In order to solve the problems existing in the technical solution of the patent with publication number CN116282521A, the inventors of this patent have developed the technical solution in the Chinese patent with publication number CN116675336A, entitled "Method for deep synergistic denitrification of urban sewage using secondary influent as electron donor". In the technical solution of the patent with publication number CN116675336A, a denitrification filter is also used, but the mixed liquid of the secondary effluent of the urban sewage treatment plant and the filtered secondary influent is used as the influent of the denitrification filter. The quartz sand filler of the denitrification filter is covered with a biofilm containing denitrifying bacteria, hydrolytic acidifying bacteria and anaerobic ammonia oxidizing bacteria. In this method, the average total nitrogen in the effluent is 0.51 mg / L, and the average removal rate is 97.68%, which perfectly solves the problem 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 effluent COD and ammonia nitrogen 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 publication number CN116282521A and the paper "Performance and mechanisms of advanced synergistic nitrogen removal using organics and NH4 +-N from secondary influent as electron donors》), resulting in the effluent COD rising to a value close to the upper limit of the standard. Moreover, the total phosphorus in the effluent of this method is 0.69 mg / L, which is almost not removed (from the paper "Performance and mechanisms of advanced synergistic nitrogen removal using organics and NH4+-N from secondary influent as electron donors" published for the patent content with publication number CN116675336A), and the problem of phosphorus removal is still not solved. The existing conventional phosphorus removal process is coagulation, sedimentation and filtration: phosphate reacts with the metal ions in the coagulant to form a precipitate, which is then formed after coagulation and removed by precipitation, and the small flocs are removed by filtration. This phosphorus removal process and even the entire carbon, nitrogen and phosphorus synergistic deep treatment process have the problems of long process flow, many types and large amounts of chemical agents, high operating costs, and easy secondary pollution.

[0008] Therefore, there is an urgent need for a carbon, nitrogen and phosphorus coordinated deep treatment technology for urban sewage with a short process flow, no need for external carbon source, low operating cost, no secondary pollution, and good carbon, nitrogen and phosphorus removal effect.

[0009] Summary of the Invention

[0010] The technical problem to be solved by the present invention is to overcome the defects of the existing technology and provide a method for the coordinated deep treatment of carbon, nitrogen and phosphorus in urban sewage based on biological manganese oxide, which can remove carbon, nitrogen and phosphorus in the secondary effluent of actual urban sewage treatment plants at low cost, synchronously and efficiently.

[0011] In order to solve the above technical problems, the technical solution of the present invention is: a method for the coordinated deep treatment of carbon, nitrogen and phosphorus in urban sewage based on biological manganese oxide, comprising:

[0012] S1, denitrification filter configured with upflow;

[0013] S2, startup phase:

[0014] The mixed solution 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 solution with a manganese concentration of 3.0 mg / L. Hydrolytic acidifying bacteria, denitrifying bacteria, anaerobic ammonia oxidizing bacteria and manganese oxidizing bacteria were inoculated in the denitrification filter, and the ratio of the secondary influent to the secondary effluent in the mixed solution was gradually increased to 3%.

[0015] When gradually increasing the ratio of secondary inlet water to secondary effluent in the mixed liquor, wait until the effluent COD, ammonia nitrogen, total nitrogen, total phosphorus, and manganese concentrations are stable before proceeding to the next increase;

[0016] 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;

[0017] S3, stable phase:

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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%.

[0022] 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.

[0023] 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.

[0024] Furthermore, in S3, each backwashing time is 3 to 5 minutes, and the backwashing intensity is 10 to 12 L / (s·m 2 ).

[0025] After adopting the above technical solution, the present invention has the following beneficial effects:

[0026] (1) The removal efficiency of ammonia nitrogen is extremely high: the ammonia nitrogen in the effluent is reduced to 0.024 mg / L, and the removal rate reaches 99.24%. The anaerobic ammonia oxidizing bacteria cultured and domesticated in the denitrification filter of the present invention are more efficient. They are in an advantageous position when competing with denitrifying bacteria for nitrite nitrogen, and will preferentially use nitrite nitrogen as an electron acceptor to oxidize ammonia nitrogen into nitrogen gas, so they can remove almost all ammonia nitrogen. In addition, the highly efficient anaerobic ammonia oxidizing bacteria can remove extremely low concentrations of ammonia nitrogen. In the technical solution of the patent with publication number CN116282521A, the ammonia nitrogen in the effluent is reduced to 0.60-0.71 mg / L; in the technical solution of the patent with publication number CN116675336A, the ammonia nitrogen in the effluent 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 influent as electron donors》). The effluent ammonia nitrogen of the present invention is significantly lower than that of the effluent ammonia nitrogen in the solutions of the above two patents.

[0027] (2) The total phosphorus removal efficiency is extremely high: the average total phosphorus content in the effluent is reduced to 0.014 mg / L, with a removal rate of 95.15%. The denitrification filter developed by the present invention has the ability to enhance chemical phosphorus removal, because when the same influent is reacted in a beaker, the total phosphorus content in the effluent is 0.068 mg / L, which exceeds the Class III water standard in the "Surface Water Environmental Quality Standard" (GB 3838-2002).

[0028] (3) Manganese is efficiently removed: The manganese content in the effluent is reduced to 0.077 mg / L, achieving a removal rate of 97.45%. The denitrification filter developed by the present invention enhances manganese removal capabilities, significantly reducing manganese content in the effluent. Compared to the 0.2 mg / L effluent manganese concentration in the patent solution with publication number CN116282521A, the present invention significantly reduces manganese content in the effluent.

[0029] (4) Achieved efficient COD removal: The hydrolytic bacteria cultivated and domesticated by the present invention are more efficient. When the influent contains a large amount of easily degradable organic matter, the effluent COD can be reduced to 7.80 mg / L. Although the patent with publication number CN116282521A also reduced the effluent COD to 8.2 mg / L, the influent of its improved denitrification filter is secondary effluent, which mainly contains difficult-to-degrade organic matter. When the organic matter is difficult to degrade, it is easy to cultivate hydrolytic bacteria, but the ability to remove COD is not as good as the present invention. The influent of the patent with publication number CN116675336A is a mixture of secondary effluent and secondary influent, and its influent COD is 45 mg / L, and the average effluent COD is 17.26 mg / L. When easily degradable organic matter exists, the easily degradable organic matter will be removed first, resulting in the inhibition and death of the hydrolytic bacteria that remove the difficult-to-degrade organic matter. The hydrolysis effect is not ideal, so the effluent COD is about 17.26 mg / L. The influent COD of patent publication number CN116675336A is lower than that of the present invention, indicating that the influent of the present invention contains more easily degradable organic matter. However, the effluent COD is actually higher than that of the present invention. This comparison clearly demonstrates that the hydrolytic bacteria cultured and domesticated in the present invention are more efficient and can still effectively remove COD in the presence of a large amount of easily degradable organic matter.

[0030] (5) Realizing the simultaneous, efficient and coordinated removal of carbon, nitrogen and phosphorus: The present invention can simultaneously reduce COD, ammonia nitrogen, total nitrogen and total phosphorus to below the Class III water quality standard in the "Surface Water Environmental Quality Standard" (GB 3838-2002) in one reactor.

[0031] (6) Low operating cost: The present invention only requires the addition of about 3.0 mg / L of manganese. Calculated based on the market price of 3,000 yuan / t manganese sulfate, the operating cost is only about 0.02 yuan / t urban sewage.

[0032] (7) No secondary pollution: The present invention only requires the addition of manganese, and the generated biological manganese oxide will be tightly attached to the filler and will not flow away with the effluent; the manganese content in the effluent is less than 0.1 mg / L, meeting the "Sanitary Standard for Drinking Water" (GB 5749-2022).

[0033] In summary, the present invention effectively solves the problems of long process flow for the coordinated deep treatment of carbon, nitrogen and phosphorus in urban sewage, large amount of chemical reagents, high operating costs, easy secondary pollution, and less than ideal carbon, nitrogen and phosphorus removal effect, and achieves low-cost, synchronous, efficient and coordinated removal of carbon, nitrogen and phosphorus. After being treated in a denitrification filter, the secondary effluent of a municipal sewage treatment plant can be reduced from the Class B standard in the "Pollutant Discharge Standard for Municipal Sewage Treatment Plants" (GB 18918-2002) to the Class III standard in the "Surface Water Environmental Quality Standard" (GB 3838-2002). This method has high application value and is conducive to promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG1 is a flow chart of the method for the coordinated deep treatment of carbon, nitrogen and phosphorus in urban sewage based on biological manganese oxide according to the present invention;

[0035] FIG2 is a simplified structural diagram of a processing system configured in the present invention;

[0036] FIG3 is a diagram showing the removal effect of COD during treatment according to an embodiment of the present invention;

[0037] FIG4 is a diagram showing the removal effect of nitrate nitrogen during treatment in an embodiment of the present invention;

[0038] FIG5 is a diagram showing the removal effect of ammonia nitrogen during treatment according to an embodiment of the present invention;

[0039] FIG6 is a diagram showing the removal effect of nitrite nitrogen during treatment according to an embodiment of the present invention;

[0040] FIG7 is a diagram showing the removal effect of total nitrogen as the treatment proceeds in an embodiment of the present invention;

[0041] FIG8 is a diagram showing the removal effect of total phosphorus as the treatment proceeds in an embodiment of the present invention;

[0042] FIG9 is a diagram showing the effect of manganese removal during treatment in an embodiment of the present invention;

[0043] In the figure, 1. Denitrification filter; 11. Water inlet layer; 12. Support layer; 13. Filling layer; 14. Water outlet layer; 15. Water inlet; 16. Water outlet; 2. Pump; 3. Water tank; 4. Water inlet valve; 5. Backwash valve. DETAILED DESCRIPTION

[0044] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments in conjunction with the accompanying drawings.

[0045] As shown in Figure 1, a method for the coordinated deep treatment of carbon, nitrogen and phosphorus in urban sewage based on biological manganese oxide includes:

[0046] S1, denitrification filter 1 configured with upflow;

[0047] Specifically, the denitrification filter tank 1 comprises, from bottom to top, an inlet layer 11, a support layer 12, a packing layer 13, and an outlet layer 14. The inlet layer 14 is provided with an inlet 15. Both the support layer 12 and the packing layer 13 are made of quartz sand, with the particle size of the quartz sand in the support layer 12 being larger than that of the packing layer 13. The outlet layer 14 is provided with an outlet 16. The support layer 12 is 10 cm thick, and the particle size of the quartz sand is 1 to 2 cm. The packing layer 13 is 60 cm thick, and the particle size of the quartz sand is 2 to 4 mm.

[0048] S2, startup phase:

[0049] The mixed solution of the secondary effluent and the secondary influent of an actual urban sewage treatment plant was used as the influent of the denitrification filter 1. Manganese sulfate was added to the mixed solution with a manganese concentration of 3.0 mg / L. Hydrolytic acidifying bacteria, denitrifying bacteria, anaerobic ammonia oxidizing bacteria, and manganese oxidizing bacteria were inoculated in the denitrification filter 1, and the ratio of the secondary influent to the secondary effluent in the mixed solution was gradually increased to 3%.

[0050] In the process of 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;

[0051] 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;

[0052] The stability of the effluent COD, ammonia nitrogen, total nitrogen, total phosphorus, and manganese concentrations 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.

[0053] In this step, 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.

[0054] In this step, the initial secondary inlet / secondary effluent ratio is 1%, resulting in an inlet ammonia nitrogen concentration of approximately 1.0 mg / L. Once the ratio increases to 3%, the inlet ammonia nitrogen concentration rises to approximately 3.2 mg / L. The ratio of secondary inlet to secondary effluent in the mixed solution is gradually increased, using the ammonia nitrogen concentration as a reference, by 0.2-0.3 mg / L at a time.

[0055] S3, stable phase:

[0056] The denitrification filter was fed with a mixture of secondary effluent and secondary influent from an actual urban sewage treatment plant. Manganese sulfate was added to the mixture, and the manganese concentration was 3.0 mg / L. The ratio of secondary influent to secondary effluent in the mixture was 3%. The hydraulic retention time was 3 to 4 hours, the backwash cycle was 9 to 11 days, the backwash time was 3 to 5 minutes, and the backwash intensity was 10 to 12 L / (s·m 2 ).

[0057] Figure 2 is a simplified structural diagram of the treatment system. As shown in Figure 2, the treatment system includes a denitrification filter 1, a pump 2, a water tank 3, an inlet pipe, and a backwash pipe. The water tank 3 is connected to the water inlet of the denitrification filter 1 via the inlet pipe. The pump 2 is connected in series to the inlet pipe to provide liquid inflow power. The inlet pipe is also equipped with an inlet valve 4 with an adjustable opening. The backwash pipe is also connected to the water inlet 15 of the denitrification filter 1 and is equipped with a backwash valve 5 with an adjustable opening.

[0058] Figures 3, 4, 5, 6, 7, 8 and 9 are the removal effect diagrams of COD, nitrate nitrogen, ammonia nitrogen, nitrite nitrogen, total nitrogen, total phosphorus and manganese during the treatment process. COD, nitrate nitrogen, ammonia nitrogen, nitrite nitrogen, total nitrogen, total phosphorus and manganese decreased 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. mg / L, and the removal rates were 84.14%~85.02%, 96.67%~97.26%, 99.00%~99.35%, 92.72%~93.93%, 96.91%~97.30%, 95.08%~95.31%, 97.36%~97.49% respectively; the average concentrations were 7.80mg / L, 0.51mg / L, 0.024mg / L, 0.011mg / L, 0.63mg / L, 0.014mg / L, and 0.077mg / L respectively, and the average removal rates were 84.72%, 97.02%, 99.24%, 93.60%, 97.17%, 95.15%, and 97.45% respectively. The effluent COD, ammonia nitrogen, total nitrogen and total phosphorus all meet the Class III water quality standards in the "Surface Water Environmental Quality Standards" (GB 3838-2002); the effluent manganese meets the "National Drinking Water Quality Standards" (GB 5749-2022).

[0059] The details are as follows:

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

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

[0062] Organic matter in the secondary effluent of municipal wastewater treatment plants (MSTPs) is recalcitrant organic matter that is not removed during the secondary biochemical treatment process. Nitrogen in the secondary effluent primarily exists as nitrate nitrogen, along with certain amounts of organic nitrogen (such as protein and microorganisms), ammonia nitrogen, and nitrite nitrogen. Phosphorus in the secondary effluent is primarily inorganic phosphorus (phosphate).

[0063] The secondary influent of a municipal sewage treatment plant becomes secondary effluent after secondary biochemical treatment. Therefore, the organic matter in the secondary influent includes both the easily degradable organic matter removed during the secondary biochemical treatment process of the municipal sewage treatment plant and the difficult-to-degrade organic matter remaining in the secondary effluent.

[0064] During the startup process, a biofilm will gradually form on the filter material surface of the denitrification filter 1, which includes biological manganese oxides, manganese oxidizing bacteria, hydrolytic bacteria, and anaerobic ammonia oxidizing bacteria. In the denitrification filter 1, biological manganese oxides and hydrolytic bacteria can convert refractory organic matter into easily degradable organic matter in the presence of easily degradable organic matter (from the secondary influent); at the same time, organic nitrogen and organic phosphorus are converted into ammonia nitrogen and phosphate respectively in this process. The inoculated denitrifying bacteria use the oxidation and hydrolysis products of the easily degradable organic matter and 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 generated ammonia nitrogen and the ammonia nitrogen in the influent as electron donors to reduce the generated nitrite nitrogen to nitrogen gas. The remaining nitrite nitrogen is further reduced to nitrogen gas by the denitrifying bacteria, thereby achieving the removal of carbon and phosphorus.

[0065] Manganese in the influent and manganese produced by the reduction of biological manganese oxides can remove phosphates through chemical phosphorus removal. The specific removal method is that phosphates are first adsorbed by microorganisms and biological manganese oxides attached to the surface of the filler, and manganese is also adsorbed by microorganisms and biological manganese oxides. After adsorption on the filler, local high concentrations of phosphates and manganese will be formed, which is beneficial to the removal of phosphorus. In addition, the filler particle size used in the present invention is relatively small, 2 to 4 mm. The filler has a large specific surface area, and irregular microorganisms and biological manganese oxides are more easily attached to the surface of the filler, which is beneficial to improve the adsorption capacity of phosphate and manganese, and achieve the removal of phosphorus and manganese. In addition, the multiple adsorption of phosphates by the denitrification filter layer can ensure the phosphorus removal effect; furthermore, the growth process of microorganisms in the filter layer near the effluent will also absorb phosphorus synthesis cells, further reducing the concentration of phosphorus. Therefore, the denitrification filter 1 of the present invention has the ability to enhance chemical phosphorus removal, and the entire treatment method can achieve efficient removal of phosphorus. Compared with the patent with publication number CN116282521A, the phosphorus removal and manganese removal effects of the present invention are improved because:

[0066] In the present invention, the secondary effluent and the secondary influent are mixed as the influent of the denitrification filter, the dissolved oxygen concentration is about 2.5 mg / L, the manganese concentration of the influent is about 3.0 mg / L, and 1 mg Mn 2+ Theoretically, 0.29 mg of dissolved oxygen is required to oxidize MnO2. The dissolved oxygen in the influent of the present invention can convert Mn 2+ All of them are oxidized to biological manganese oxides (there is sufficient dissolved oxygen in the influent), and the oxidized biological manganese oxides will adhere to the filler in the form of tiny particles, increasing the specific surface area of ​​the filler, which is beneficial to the adsorption of phosphate and manganese. Biological manganese oxides have a strong adsorption capacity for manganese, so it is beneficial to the removal of manganese.

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

[0068] In addition, the present invention can utilize secondary influent with different carbon-nitrogen ratios (COD / TN) to provide electron donors for deep denitrification, and adapt to secondary influent with different carbon-nitrogen ratios by adjusting the contribution rate of short-range denitrification-anaerobic ammonium oxidation and denitrification to total nitrogen removal, thereby achieving efficient and low-cost removal of total nitrogen. If the carbon-nitrogen ratio in the secondary influent is relatively high, efficient and low-cost removal of total nitrogen can be achieved by increasing the contribution rate of denitrification to total nitrogen; if the carbon-nitrogen ratio in the secondary influent is relatively low, efficient and low-cost removal of total nitrogen can be achieved by increasing the contribution rate of short-range denitrification-anaerobic ammonium oxidation to total nitrogen. The present invention is also suitable for treating secondary effluents with different total nitrogen concentrations, because there are sufficient organic matter and ammonia nitrogen in the secondary influent to provide electron donors for deep denitrification.

[0069] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A method for the coordinated deep treatment of carbon, nitrogen and phosphorus in urban sewage based on biological manganese oxide, characterized in that: include: S1, denitrification filter configured with upflow; S2, startup phase: The mixed solution 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 solution with a manganese concentration of 3.0 mg / L. Hydrolytic acidifying bacteria, denitrifying bacteria, anaerobic ammonia oxidizing bacteria and manganese oxidizing bacteria were inoculated in the denitrification filter, and the ratio of the secondary influent to the secondary effluent in the mixed solution was gradually increased to 3%. In the process of 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; 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; S3, stable phase: 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.

2. The method for the coordinated deep treatment of carbon, nitrogen and phosphorus in urban sewage based on biological manganese oxide according to claim 1, characterized in that: In S1, the denitrification filter tank comprises an inlet layer, a supporting layer, a filler layer and an outlet layer from bottom to top; 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 in the supporting layer is larger than that of the quartz sand in the filler layer; the outlet layer is provided with an outlet.

3. The method for the coordinated deep treatment of carbon, nitrogen and phosphorus in urban sewage based on biological manganese oxide according to claim 2, characterized in that: 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 filling layer is 60 cm, and the particle size of the quartz sand is 2 to 4 mm.

4. The method for the coordinated deep treatment of carbon, nitrogen and phosphorus in urban sewage based on biological manganese oxide according to claim 1, characterized in that: In S2, at the beginning of the startup phase, the ratio of secondary inlet water to secondary outlet water in the mixed liquor is 1%.

5. The method for the coordinated deep treatment of carbon, nitrogen and phosphorus in urban sewage based on biological manganese oxide according to claim 1, characterized in that: 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~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 the coordinated deep treatment of carbon, nitrogen and phosphorus in urban sewage based on biological manganese oxide according to claim 1, characterized in that: 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.

7. The method for the coordinated deep treatment of carbon, nitrogen and phosphorus in urban sewage based on biological manganese oxide according to claim 1, characterized in that: In S3, each backwashing time is 3 to 5 minutes, and the backwashing intensity is 10 to 12 L / (s·m 2 ).

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