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

Abstract

The invention relates to the field of town sewage treatment, in particular to a town sewage carbon-nitrogen-phosphorus synergistic advanced treatment method based on biological manganese oxide. The method comprises the following steps: S1, configuring an upward flow denitrification filter tank; s2, a starting stage: taking a mixed solution of secondary effluent and secondary influent water of an actual town sewage treatment plant and manganese sulfate as influent water of a denitrification filter tank with the manganese concentration of 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 of the secondary influent water to the secondary effluent water in the mixed solution to 3%; s3, a stable stage: taking a mixed solution of secondary effluent and secondary inlet water of an actual town sewage treatment plant and manganese sulfate as inlet water of the denitrification filter tank, controlling the manganese concentration to be 3.0 mg / L, controlling the hydraulic retention time to be 3-4 hours, and controlling the backwashing period to be 9-11 days. The method can synchronously and efficiently remove carbon, nitrogen and phosphorus in the secondary effluent of the actual town sewage treatment plant at low cost.

Description

Technical Field

[0001] The invention relates to the field of urban sewage treatment, and in particular to a method for 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, and their excessive discharge will cause the receiving water to become black and smelly and eutrophic. In order to reduce the discharge of carbon, nitrogen and phosphorus and improve the water environment quality, my country has built many urban sewage treatment plants, and the emission standards for carbon, nitrogen and phosphorus are becoming increasingly stringent. For example, in the "Emission Limits of Major Water Pollutants from Urban Sewage Treatment Plants" (DB 5301 / T 43-2020), the Class A emission standards for COD, ammonia nitrogen, total nitrogen and total phosphorus are 20mg / L, 1.0mg / L, 5mg / L and 0.05mg / L respectively; some key areas even require the Class III water standards in the "Surface Water Environmental Quality Standards" (GB 3838-2002), which require COD, ammonia nitrogen, total nitrogen and total phosphorus to be no higher than 20mg / L, 1.0mg / L, 1.0mg / L and 0.05mg / L respectively.

[0003] It is difficult for urban sewage treatment plants to achieve the above standards for carbon, nitrogen and phosphorus in effluent by secondary biochemical treatment alone, so urban sewage needs deep treatment. The organic matter in the secondary effluent is mainly difficult to degrade; the nitrogen is mainly nitrate nitrogen, and there are also small amounts of organic nitrogen, ammonia nitrogen and nitrite nitrogen; the phosphorus is mainly inorganic phosphorus.

[0004] Considering that biological denitrification can be widely used for deep denitrification of urban sewage due to its high efficiency, low cost and low secondary pollution, the inventor of this patent has previously developed a technical solution in a Chinese patent with publication number CN116282521A and patent name "A method for deep synergistic denitrification of urban sewage based on improved denitrification filter". In this technical solution, a modified denitrification filter is used, and the secondary effluent from a municipal 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, anaerobic ammonia oxidizing bacteria, and biological manganese oxides. The filter is used to deeply treat municipal 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 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 of manganese is not 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 inventor of this patent has developed the technical solution in the Chinese patent with publication number CN116675336A and the name of the patent is "Method for deep synergistic denitrification of urban sewage with 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, which contains denitrifying bacteria, hydrolytic acidification bacteria and anaerobic ammonia oxidizing bacteria. 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%, which perfectly solves the problem that the total nitrogen in the effluent in the patent with publication number CN116282521A has not dropped below 1 mg / L and the problem of the introduction of manganese.

[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 specification drawings in the 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》), causing the effluent COD to rise 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 coagulated to form large flocs that are removed by precipitation, and small flocs are removed by filtration. This phosphorus removal process and even the entire carbon-nitrogen-phosphorus synergistic deep treatment process have the problems of long process flow, many types and large amounts of chemical agents added, high operating costs, and easy secondary pollution.

[0008] Therefore, there is an urgent need for a carbon, nitrogen and phosphorus synergistic deep treatment technology for urban sewage with a short process flow, no need for external carbon sources, low operating costs, no secondary pollution, and good carbon, nitrogen and phosphorus removal effects. Summary of the invention

[0009] The technical problem to be solved by the present invention is to overcome the defects of the prior art 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.

[0010] 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:

[0011] S1, denitrification filter configured with upward flow;

[0012] S2, startup phase:

[0013] The mixed solution of the secondary effluent and the secondary influent of the 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%. Among them,

[0014] In the process of gradually increasing the ratio of secondary influent to secondary effluent in the mixed liquor, the next increase shall be made after the concentrations of effluent COD, ammonia nitrogen, total nitrogen, total phosphorus, and manganese are stable;

[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, and the manganese concentration was 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 backwashing 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 filling layer is 60 cm, and the particle size of the quartz sand is 2 to 4 mm.

[0020] Further, 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 do not fluctuate by 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 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.

[0026] (2) The removal efficiency of total phosphorus is extremely high: the average total phosphorus in the effluent is reduced to 0.014 mg / L, and the removal rate reaches 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 in the effluent is 0.068 mg / L, which is higher than the Class III water standard in the "Surface Water Environmental Quality Standard" (GB 3838-2002).

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

[0028] (4) Achieved efficient removal of COD: The hydrolytic bacteria cultivated and domesticated by the present invention are more efficient, and 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, and the organic matter is difficult-to-degrade 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 invention. The influent of the patent with publication number CN116675336A is a mixed solution 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, 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 influent COD of the present invention, indicating that the influent of the present invention contains more easily degradable organic matter; however, its effluent COD is higher than the effluent COD of the present invention. By comparison, it is fully demonstrated that the hydrolytic bacteria cultivated and domesticated by the present invention are more efficient and can still efficiently remove COD when there are a large amount of easily degradable organic matter.

[0029] (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.

[0030] (6) Low operating cost: The present invention only requires the addition of about 3.0 mg / L of manganese. According to the market price of 3,000 yuan / t manganese sulfate, the operating cost is only about 0.02 yuan / t urban sewage.

[0031] (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 in the effluent is less than 0.1 mg / L, meeting the "Sanitary Standard for Drinking Water" (GB 5749-2022).

[0032] In summary, the present invention effectively solves the problems of long process flow of carbon, nitrogen and phosphorus coordinated deep treatment of urban sewage, many types and large amounts of chemical reagents, high operating costs, easy secondary pollution, and unsatisfactory removal effect of carbon, nitrogen and phosphorus, and realizes low-cost, synchronous, efficient and coordinated removal of carbon, nitrogen and phosphorus. After being treated in a denitrification filter tank, 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), which has high application value and is conducive to promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It 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 of the present invention;

[0034] Figure 2 A simplified structural diagram of a processing system configured for the present invention;

[0035] Figure 3 This is a diagram showing the effect of COD removal during treatment in an embodiment of the present invention;

[0036] Figure 4 This is a diagram showing the effect of removing nitrate nitrogen during treatment in an embodiment of the present invention;

[0037] Figure 5 This is a diagram showing the effect of removing ammonia nitrogen during treatment in an embodiment of the present invention;

[0038] Figure 6 This is a diagram showing the effect of removing nitrite nitrogen during treatment in an embodiment of the present invention;

[0039] Figure 7 This is a diagram showing the effect of total nitrogen removal during treatment in an embodiment of the present invention;

[0040] Figure 8 This is a diagram showing the effect of total phosphorus removal during treatment in an embodiment of the present invention;

[0041] Fig. 9 This is a diagram showing the effect of manganese removal during treatment in an embodiment of the present invention;

[0042] In the figure, 1. denitrification filter; 11. water inlet layer; 12. supporting layer; 13. packing 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

[0043] 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.

[0044] like Figure 1 As shown, a method for the coordinated deep treatment of carbon, nitrogen and phosphorus in urban sewage based on biological manganese oxide includes:

[0045] S1, denitrification filter 1 configured with upward flow;

[0046] Specifically, the configured denitrification filter 1 includes an inlet layer 11, a supporting layer 12, a packing layer 13 and an outlet layer 14 from bottom to top; the inlet layer 14 is provided with an inlet 15; the supporting layer 12 and the packing layer 13 are quartz sand respectively, and the particle size of the quartz sand of the supporting layer 12 is larger than the particle size of the quartz sand of the packing layer 13; the outlet layer 14 is provided with an outlet 16. The thickness of the supporting layer 12 is 10 cm, and the particle size of the quartz sand is 1-2 cm; the thickness of the packing layer 13 is 60 cm, and the particle size of the quartz sand is 2-4 mm.

[0047] S2, startup phase:

[0048] The mixed solution of the secondary effluent and the secondary influent of the actual urban sewage treatment plant is used as the influent of the denitrification filter 1, and manganese sulfate is added to the mixed solution, and the manganese concentration is 3.0 mg / L; hydrolytic acidifying bacteria, denitrifying bacteria, anaerobic ammonia oxidizing bacteria and manganese oxidizing bacteria are inoculated in the denitrification filter 1, and the ratio of the secondary influent to the secondary effluent in the mixed solution is gradually increased to 3%; wherein,

[0049] In the process of gradually increasing the ratio of secondary influent to secondary effluent in the mixed liquor, the next increase is carried out after the concentrations of effluent COD, ammonia nitrogen, total nitrogen, total phosphorus, and manganese are stable;

[0050] 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;

[0051] The stability of effluent COD, ammonia nitrogen, total nitrogen, total phosphorus, and manganese concentrations means that the fluctuation of effluent COD, ammonia nitrogen, total nitrogen, total phosphorus, and manganese concentrations relative to the average concentrations of COD, ammonia nitrogen, total nitrogen, total phosphorus, and manganese does not exceed 10% within 13 to 15 consecutive days.

[0052] 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.

[0053] In this step, at first, the secondary inlet water / secondary outlet water is 1%, and the inlet ammonia nitrogen is about 1.0 mg / L. After the secondary inlet water / secondary outlet water is increased to 3%, the inlet ammonia nitrogen increases to about 3.2 mg / L. The ratio of secondary inlet water to secondary outlet water in the mixed solution is gradually increased, with the ammonia nitrogen concentration as a reference, and each increase is 0.2-0.3 mg / L.

[0054] S3, stable phase:

[0055] The mixed solution of the secondary effluent and the secondary influent of the actual urban sewage treatment plant was used as the influent of the denitrification filter. Manganese sulfate was added to the mixed solution, and the manganese concentration was 3.0 mg / L. The ratio of the secondary influent to the secondary effluent in the mixed solution was 3%. The hydraulic retention time was 3 to 4 hours, the backwashing cycle was 9 to 11 days, the backwashing time was 3 to 5 minutes each time, and the backwashing intensity was 10 to 12 L / (s·m 2 ).

[0056] Figure 2 The structural diagram of the processing system is as follows: Figure 2 As shown, the treatment system includes a denitrification filter 1, a pump 2, a water tank 3, a water inlet pipe and a backwash pipe. The water tank 3 is connected to the water inlet of the denitrification filter 1 through the water inlet pipe. The pump 2 is connected in series to the water inlet pipe to provide liquid inlet power. The water inlet pipe is also equipped with a water inlet valve 4, and the opening of the water inlet valve 4 is adjustable. The backwash pipe is also connected to the water inlet 15 of the denitrification filter 1. The backwash pipe is equipped with a backwash valve 5, and the opening of the backwash valve 5 is also adjustable.

[0057] Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 and Fig. 9They are the removal effect diagrams of COD, nitrate nitrogen, ammonia nitrogen, nitrite nitrogen, total nitrogen, total phosphorus and manganese during the treatment process. The removal rates of COD, nitrate nitrogen, ammonia nitrogen, nitrite nitrogen, total nitrogen, total phosphorus and manganese were reduced from about 50mg / L, 17mg / L, 3.2mg / L, 0.17mg / L, 22mg / L, 0.3mg / L and 3.0mg / L to 7.66-8.05mg / L, 0.47-0.57mg / L, 0.021-0.032mg / L, 0.010-0.013mg / L, 0.60-0.69mg / L, 0.013-0.014mg / L and 0.076-0.080mg / L, 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 "Sanitary Standards for Drinking Water" (GB 5749-2022).

[0058] The details are as follows:

[0059]

[0060] In this embodiment, the 0th to 198th day is the start-up phase, and the 199th day is the stable 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 urban sewage treatment plants is not removed during the secondary biochemical treatment process of urban sewage treatment plants and is difficult to degrade. The main form of nitrogen in the secondary effluent is nitrate nitrogen, and it also contains a certain amount of organic nitrogen (such as protein, microorganisms), ammonia nitrogen, and nitrite nitrogen. The phosphorus in the secondary effluent is mainly 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 of the municipal sewage treatment plant and the difficultly degradable organic matter remaining in the secondary effluent.

[0064] During the startup process, a biofilm will gradually form on the filter 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 phosphates, 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, and the remaining nitrite nitrogen is further reduced to nitrogen gas by the denitrifying bacteria, thereby achieving the removal of carbon and nitrogen.

[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 phosphate 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, and the filler has a large specific surface area. 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, phosphorus synthesis cells will also be absorbed during the growth of microorganisms in the filter layer close to the effluent, 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 is mixed with the secondary influent and used as the influent of the denitrification filter. The dissolved oxygen concentration 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 for oxidation to MnO2. The dissolved oxygen in the influent of the present invention can convert Mn 2+All of them are oxidized to biological manganese oxides (sufficient dissolved oxygen in the influent water), 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 is used as the inlet of the denitrification filter, and its dissolved oxygen concentration is about 0.5 mg / L, and the inlet manganese sulfate concentration is about 0.5 mg / L. The dissolved oxygen in the inlet is used to oxidize manganese, organic matter, ammonia nitrogen, etc., resulting in insufficient dissolved oxygen in the inlet to oxidize all manganese in the inlet. 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 rates 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 effluent 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] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope 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 upward flow; S2, startup phase: The mixed solution of the secondary effluent and the secondary influent of the 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%. Among them, In the process of gradually increasing the ratio of secondary influent to secondary effluent in the mixed liquor, the next increase is carried out after the concentrations of effluent COD, ammonia nitrogen, total nitrogen, total phosphorus, and manganese are stable; 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, and the manganese concentration was 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 backwashing 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 is 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 of the supporting layer is larger than that of the quartz sand of 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 is 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 5g / L~8g / L, 5g / L~6g / L, 3g / L~4g / L, and 3g / L~4g / 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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