Method for synchronously realizing phosphorus enrichment and denitrification by using urban sewage carbon source

Abstract

The invention belongs to the field of water treatment, and particularly relates to a method for synchronously realizing phosphorus enrichment and denitrification by using a municipal sewage carbon source, which comprises the following steps: a) adding municipal sewage into a bio-membrane reactor filled with a filler forming a phosphorus-accumulating bio-membrane; b) under an anaerobic condition, enabling the phosphorus-accumulating biological membrane to release phosphorus by utilizing an organic carbon source in the sewage; c) discharging a part of treated sewage into a recovery tank for storage as recovery liquid; d) performing aerobic aeration treatment on the residual sewage, so that phosphorus in the sewage is absorbed by the phosphorus-accumulating biological membrane, and nitrogen in the sewage is converted and removed by the phosphorus-accumulating biological membrane; e) stopping aeration, and discharging all the treated sewage from the bio-membrane reactor; and f) returning the recovery liquid to the bio-membrane reactor, and starting a new cycle from the step (a). According to the method, phosphorus removal / enrichment and denitrification of the sewage can be synchronously realized by utilizing organic carbon contained in the urban sewage in a single-stage system, and a carbon source does not need to be additionally added.

Description

Technical Field

[0001] This invention belongs to the field of water treatment, and in particular relates to a method for simultaneously achieving phosphorus enrichment and denitrification using carbon sources from urban sewage. Background Technology

[0002] The contradiction between resource scarcity and environmental pollution is driving the rapid development of phosphorus recovery concepts and technologies. As the primary substrate for phosphorus recovery, urban wastewater contains enough phosphorus to meet 15-20% of human phosphorus needs. Biofilm phosphorus recovery technology utilizes the phosphorus absorption and release properties of polyphosphate biofilms under alternating aerobic and anaerobic conditions to remove and enrich phosphates, resulting in a concentrated phosphorus solution. Biofilm phosphorus recovery technology avoids phosphorus loss during the recovery process, simplifies the recovery steps, and has significant advantages and development potential in urban wastewater phosphorus recovery.

[0003] However, although existing biofilm phosphorus recovery technologies can effectively remove and recover (or enrich) phosphorus in wastewater, they usually require a separate denitrification system to avoid the impact of nitrogen in wastewater on the phosphorus recovery unit, and additional carbon sources need to be added to enhance the biological phosphorus release performance to obtain a high-concentration phosphorus-rich solution. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method for simultaneously achieving phosphorus enrichment and denitrification using carbon sources in urban sewage. This method can simultaneously achieve phosphorus removal / enrichment and denitrification in a single-stage system using organic carbon contained in urban sewage, without the need for additional carbon source addition.

[0005] This invention provides a method for simultaneously achieving phosphorus enrichment and nitrogen removal using carbon sources in urban wastewater, comprising the following steps:

[0006] a) A certain amount of urban sewage is added to the biofilm reactor; the biofilm reactor is filled with packing material, on which a polyphosphate biofilm is formed. The polyphosphate biofilm is formed by repeatedly alternating anaerobic and aerobic treatment of the packing material in a water body containing activated sludge; the influent COD during the anaerobic treatment is 200-300 mg / L; the dissolved oxygen content during the aerobic treatment is 6-8 mg / L, the influent phosphorus content is 20-40 mg / L, and the ammonia nitrogen content is 30-50 mg / L.

[0007] b) Stirring under anaerobic conditions allows the polyphosphate biofilm to release phosphorus from the organic carbon source in the wastewater;

[0008] c) A portion of the wastewater treated in step b) is discharged into a recovery tank for storage as recovery liquid;

[0009] d) Turn on the aeration device to perform aerobic aeration on the remaining wastewater in the biofilm reactor after the treatment in step b), so that the phosphorus in the wastewater is absorbed by the polyphosphate biofilm and the nitrogen in the wastewater is converted and removed by the polyphosphate biofilm.

[0010] e) Turn off the aeration device and discharge all the wastewater treated in step d) from the biofilm reactor;

[0011] f) Return the recovered liquid to the biofilm reactor to begin a new cycle from step (a);

[0012] Steps a) to f) constitute one operating cycle, during which the wastewater treated by the biofilm reactor in step d) of each operating cycle is continuously discharged; after multiple operating cycles, the phosphorus concentration of the recovered liquid in step c) reaches the phosphorus recovery process requirements, and a batch of phosphorus recovered liquid is obtained, thus completing one phosphorus concentration cycle.

[0013] Preferably, in step a), the duration of a single anaerobic treatment is 2-6 hours, the duration of a single aerobic treatment is 2-6 hours, and the total duration of repeated alternating anaerobic and aerobic treatments is 20-30 days.

[0014] Preferably, in step a), the thickness of the polyphosphorus biofilm is 80–150 μm.

[0015] Preferably, the volume ratio of the recovered liquid returned to the biofilm reactor in step f) of the previous operating cycle to the municipal wastewater entering the biofilm reactor in step a) of the next operating cycle is 1:(1 to 2.5).

[0016] Preferably, the method further includes the following step: recovering phosphorus from the phosphorus recovery solution using a crystallization method to obtain a phosphorus product.

[0017] Preferably, in step a), the COD of the urban wastewater is 150–400 mg / L.

[0018] Preferably, in step a), the ammonia nitrogen content of the urban sewage is 15-60 mg / L.

[0019] Preferably, in step a), the total phosphorus content of the urban sewage is 5-10 mg / L.

[0020] Preferably, in step b), the stirring time under anaerobic conditions is 2 to 12 hours.

[0021] Preferably, in step d), the dissolved oxygen content of the water body undergoing aerobic aeration treatment is 6-8 mg / L, and the treatment time is 2-12 h.

[0022] Compared with existing technologies, this invention provides a method for simultaneously achieving phosphorus enrichment and denitrification using urban sewage as a carbon source, comprising the following steps: a) adding a certain amount of urban sewage to a biofilm reactor; the biofilm reactor is filled with packing material, on which a polyphosphate biofilm is formed, the polyphosphate biofilm being formed by repeatedly alternating anaerobic and aerobic treatment of the packing material in a water body containing activated sludge; the influent COD during the anaerobic treatment is 200-300 mg / L; the dissolved oxygen content during the aerobic treatment is 6-8 mg / L, the influent phosphorus content is 20-40 mg / L, and the ammonia nitrogen content is 30-50 mg / L; b) stirring under anaerobic conditions, so that the polyphosphate biofilm releases phosphorus using the organic carbon source in the sewage; c) partially discharging the sewage treated in step b) The wastewater is discharged into a recovery tank for storage as recovered liquid; d) The aeration device is turned on to perform aerobic aeration on the remaining wastewater in the biofilm reactor after the treatment in step b), so that the phosphorus in the wastewater is absorbed by the polyphosphate biofilm and the nitrogen in the wastewater is converted and removed by the polyphosphate biofilm; e) The aeration device is turned off and all the wastewater after the treatment in step d) is discharged from the biofilm reactor; f) The recovered liquid is returned to the biofilm reactor to start a new cycle from step (a); Steps a) to f) constitute one operating cycle, during which the wastewater treated by the biofilm reactor in step d) of each operating cycle is continuously discharged; After multiple operating cycles, the phosphorus concentration of the recovered liquid in step c) reaches the phosphorus recovery process requirements, and a batch of phosphorus recovered liquid is obtained, which is one phosphorus concentration cycle. The method provided by this invention effectively removes phosphorus from urban wastewater using organic carbon sources in a biofilm reactor (single-stage system). Simultaneous nitrification and denitrification effectively remove ammonia nitrogen and total nitrogen from the wastewater. All removed phosphorus enters the phosphorus recovery solution, achieving simultaneous phosphorus removal and recovery. The resulting phosphorus recovery solution can be used to prepare and produce phosphorus products using a crystallization phosphorus recovery method. This method utilizes organic carbon sources in urban wastewater in situ, eliminating the need for external organic carbon sources during denitrification and phosphorus removal / enrichment, significantly reducing carbon source addition costs during these processes. The method effectively removes organic carbon pollutants and nitrogen from water bodies and exhibits significant phosphorus enrichment capabilities. The overall process is simple, efficient, and easy to control, demonstrating good environmental and economic benefits and promising prospects for widespread application. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] This invention provides a method for simultaneously achieving phosphorus enrichment and nitrogen removal using carbon sources in urban wastewater, comprising the following steps:

[0025] a) A certain amount of urban sewage is added to a biofilm reactor; the biofilm reactor is filled with packing material on which a polyphosphate biofilm is formed.

[0026] b) Stirring under anaerobic conditions allows the polyphosphate biofilm to release phosphorus from the organic carbon source in the wastewater;

[0027] c) A portion of the wastewater treated in step b) is discharged into a recovery tank for storage as recovery liquid;

[0028] d) Turn on the aeration device to perform aerobic aeration on the remaining wastewater in the biofilm reactor after the treatment in step b), so that the phosphorus in the wastewater is absorbed by the polyphosphate biofilm and the nitrogen in the wastewater is converted and removed by the polyphosphate biofilm.

[0029] e) Turn off the aeration device and discharge all the wastewater treated in step d) from the biofilm reactor;

[0030] f) Return the recovered liquid to the biofilm reactor to begin a new cycle from step (a).

[0031] In the method provided by the present invention, in step a), the polyphosphate biofilm is formed by repeatedly alternating anaerobic and aerobic treatment of the packing material in a water body containing activated sludge under specific conditions. During the anaerobic treatment, an organic carbon source is provided, and during the aerobic treatment, phosphorus and ammonia nitrogen are provided to ensure that the formed polyphosphate biofilm has good nitrogen and phosphorus removal effects.

[0032] In the method provided by the present invention, during step a), the concentration of activated sludge in the water body is preferably 2500-3000 mg / L, specifically 2500 mg / L, 2600 mg / L, 2700 mg / L, 2800 mg / L, 2900 mg / L or 3000 mg / L.

[0033] In the method provided by this invention, during step a), the COD of the influent during the anaerobic treatment is 200-300 mg / L, specifically 200 mg / L, 210 mg / L, 220 mg / L, 230 mg / L, 240 mg / L, 250 mg / L, 260 mg / L, 270 mg / L, 280 mg / L, 290 mg / L, or 300 mg / L.

[0034] In the method provided by the present invention, during step a), the influent temperature during the anaerobic treatment of the polyphosphate biofilm is preferably 15-35℃, specifically 15℃, 16℃, 17℃, 18℃, 19℃, 20℃, 21℃, 22℃, 23℃, 24℃, 25℃, 26℃, 27℃, 28℃, 29℃, 30℃, 31℃, 32℃, 33℃, 34℃ or 35℃.

[0035] In the method provided by this invention, during step a), the dissolved oxygen content during the aerobic treatment of the polyphosphate biofilm is 6-8 mg / L, specifically 6 mg / L, 6.1 mg / L, 6.2 mg / L, 6.3 mg / L, 6.4 mg / L, 6.5 mg / L, 6.6 mg / L, 6.7 mg / L, 6.8 mg / L, 6.9 mg / L, 7 mg / L, 7.1 mg / L, 7.2 mg / L, 7.3 mg / L, 7.4 mg / L, 7.5 mg / L, 7.6 mg / L, 7.7 mg / L, 7.8 mg / L, 7.9 mg / L, or 8 mg / L.

[0036] In the method provided by this invention, during step a) of cultivating the polyphosphate biofilm, the phosphorus content of the influent during the aerobic treatment period is 20-40 mg / L, specifically 20 mg / L, 21 mg / L, 22 mg / L, 23 mg / L, 24 mg / L, 25 mg / L, 26 mg / L, 27 mg / L, 28 mg / L, 29 mg / L, 30 mg / L, 31 mg / L, 32 mg / L, 33 mg / L, 34 mg / L, 35 mg / L, 36 mg / L, 37 mg / L, 38 mg / L. 39 mg / L or 40 mg / L; the influent ammonia nitrogen content during the aerobic treatment period is 30-50 mg / L, specifically 30 mg / L, 31 mg / L, 32 mg / L, 33 mg / L, 34 mg / L, 35 mg / L, 36 mg / L, 37 mg / L, 38 mg / L, 39 mg / L, 40 mg / L, 41 mg / L, 42 mg / L, 43 mg / L, 44 mg / L, 45 mg / L, 46 mg / L, 47 mg / L, 48 mg / L, 49 mg / L or 50 mg / L.

[0037] In the method provided by the present invention, during step a), the influent temperature during the aerobic treatment of the polyphosphate biofilm is preferably 15-35℃, specifically 15℃, 16℃, 17℃, 18℃, 19℃, 20℃, 21℃, 22℃, 23℃, 24℃, 25℃, 26℃, 27℃, 28℃, 29℃, 30℃, 31℃, 32℃, 33℃, 34℃ or 35℃.

[0038] In the method provided by this invention, in step a), during the cultivation of polyphosphate biofilm, the single duration of the anaerobic treatment is preferably 2-6 hours, specifically 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, or 6 hours; the single duration of the aerobic treatment is preferably 2-6 hours, specifically 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, or 6 hours; the total time for repeatedly alternating between anaerobic and aerobic treatment is preferably 20-30 days, specifically 20 days, 21 days, 22 days, 23 days, 24 days, 25 days, 26 days, 27 days, 28 days, 29 days, or 30 days.

[0039] In the method provided by the present invention, in step a), the thickness of the polyphosphorus biofilm is preferably 80-150 μm, specifically 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 105 μm, 110 μm, 115 μm, 120 μm, 125 μm, 130 μm, 135 μm, 140 μm, 145 μm or 150 μm.

[0040] In the method provided by the present invention, in step a), the phosphorus removal rate of the polyphosphate biofilm is preferably above 95%, the total nitrogen removal rate is preferably 75-80%, and the COD removal rate is preferably 75-85%.

[0041] In the method provided by the present invention, in step a), the packing material is preferably a suspended packing material; the packing amount of the packing material in the biofilm reactor is preferably 30% to 50% of the biofilm reactor capacity, specifically 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, or 50%.

[0042] In the method provided by this invention, in step a), the COD of the urban wastewater is preferably 150-400 mg / L, specifically 150 mg / L, 170 mg / L, 200 mg / L, 230 mg / L, 250 mg / L, 270 mg / L, 300 mg / L, 320 mg / L, 350 mg / L, 370 mg / L, or 400 mg / L; the ammonia nitrogen (NH3-N) of the urban wastewater is... The preferred content is 15–60 mg / L, specifically 15 mg / L, 17 mg / L, 20 mg / L, 23 mg / L, 25 mg / L, 27 mg / L, 30 mg / L, 32 mg / L, 35 mg / L, 37 mg / L, 40 mg / L, 42 mg / L, 45 mg / L, 47 mg / L, 50 mg / L, 52 mg / L, 55 mg / L, 57 mg / L, or 60 mg / L. The total phosphorus (TP) content of the urban wastewater is preferably 5–10 mg / L, specifically 5 mg / L, 5.2 mg / L, 5.5 mg / L, 5.7 mg / L, 6 mg / L, 6.2 mg / L, 6.5 mg / L, 6.7 mg / L, 7 mg / L, 7.2 mg / L, 7.5 mg / L, 7.7 mg / L, 8 mg / L, 8.2 mg / L, 8.5 mg / L, and 8 mg / L. The concentrations are 7 mg / L, 9 mg / L, 9.2 mg / L, 9.5 mg / L, 9.7 mg / L, or 10 mg / L; the temperature of the urban wastewater is preferably 15–35℃, specifically 15℃, 16℃, 17℃, 18℃, 19℃, 20℃, 21℃, 22℃, 23℃, 24℃, 25℃, 26℃, 27℃, 28℃, 29℃, 30℃, 31℃, 32℃, 33℃, 34℃, or 35℃.

[0043] In the method provided by the present invention, in step a), the urban sewage is preferably filled into the biofilm reactor.

[0044] In the method provided by this invention, in step b), the stirring rate under anaerobic conditions is preferably 50-100 rpm, specifically 50 rpm, 55 rpm, 60 rpm, 65 rpm, 70 rpm, 75 rpm, 80 rpm, 85 rpm, 90 rpm, 95 rpm, or 100 rpm; the stirring time under anaerobic conditions is preferably 2-12 h, specifically 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h, 6 h, 6.5 h, 7 h, 7.5 h, 8 h, 8.5 h, 9 h, 9.5 h, 10 h, 10.5 h, 11 h, 11.5 h, or 12 h.

[0045] In the method provided by the present invention, in step c), the volume ratio of the amount of wastewater discharged into the recovery tank to the amount of residual wastewater in the biofilm reactor is preferably 1:(1 to 2.5), specifically 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4 or 1:2.5.

[0046] In the method provided by this invention, in step d), the dissolved oxygen content of the water body undergoing aerobic aeration treatment is preferably controlled to be 6-8 mg / L, specifically 6 mg / L, 6.1 mg / L, 6.2 mg / L, 6.3 mg / L, 6.4 mg / L, 6.5 mg / L, 6.6 mg / L, 6.7 mg / L, 6.8 mg / L, 6.9 mg / L, 7 mg / L, 7.1 mg / L, 7.2 mg / L, 7.3 mg / L, 7.4 mg / L. / L, 7.5mg / L, 7.6mg / L, 7.7mg / L, 7.8mg / L, 7.9mg / L or 8mg / L; the preferred treatment time for the aerobic aeration treatment is 2 to 12 hours, specifically 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, 8 hours, 8.5 hours, 9 hours, 9.5 hours, 10 hours, 10.5 hours, 11 hours, 11.5 hours or 12 hours.

[0047] In the method provided by this invention, in step d), the phosphorus and nitrogen concentrations of the wastewater after aerobic aeration treatment can meet the discharge requirements.

[0048] In the method provided by the present invention, steps a) to f) constitute one operating cycle, during which the wastewater treated by the biofilm reactor in step d) of each operating cycle is continuously discharged; after multiple operating cycles, the phosphorus concentration of the recovered liquid in step c) reaches the phosphorus recovery process requirements, and a batch of phosphorus recovered liquid is obtained, thus completing one phosphorus concentration cycle.

[0049] In the method provided by this invention, a certain amount of new municipal wastewater is added in step a) of each operating cycle. This process can supplement the organic carbon source for the entire wastewater treatment process, so there is no need to add new organic carbon source. In this invention, the volume ratio of the recovered liquid returned to the biofilm reactor in step f) of the previous operating cycle to the municipal wastewater entering the biofilm reactor in step a) of the next operating cycle is preferably 1:(1 to 2.5), specifically 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4 or 1:2.5.

[0050] In the method provided by the present invention, the phosphorus recovery solution contains a high concentration of phosphorus. The present invention preferably further includes the following step: recovering phosphorus from the phosphorus recovery solution by crystallization to obtain a phosphorus product.

[0051] The method provided by this invention effectively removes phosphorus from urban wastewater using organic carbon sources in a biofilm reactor (single-stage system). Simultaneous nitrification and denitrification effectively remove ammonia nitrogen and total nitrogen from the wastewater. All removed phosphorus enters the phosphorus recovery solution, achieving simultaneous phosphorus removal and recovery. The resulting phosphorus recovery solution can be used to prepare and produce phosphorus products using a crystallization phosphorus recovery method. This method utilizes organic carbon sources in urban wastewater in situ, eliminating the need for external organic carbon sources during denitrification and phosphorus removal / enrichment, significantly reducing carbon source addition costs during these processes. The method effectively removes organic carbon pollutants and nitrogen from water bodies and exhibits significant phosphorus enrichment capabilities. The overall process is simple, efficient, and easy to control, demonstrating good environmental and economic benefits and promising prospects for widespread application.

[0052] For clarity, the following examples will be used to provide a detailed description.

[0053] Example 1

[0054] Cultivation of polyphosphate biofilms

[0055] Take suspended packing carrier and activated sludge from the aeration tank of a municipal wastewater treatment plant, and mix them at a depth of 0.005m. 3 Biofilm cultivation was carried out in a sequencing batch reactor (SBR) with a sludge concentration controlled at 2500 mg / L. During cultivation, the reactor operated alternately in anaerobic and aerobic cycles. The anaerobic cycle lasted 4 hours, during which the influent COD was controlled at 300 mg / L and the influent temperature was room temperature. The aerobic cycle lasted 4 hours, during which the dissolved oxygen content was controlled at 7 mg / L, the influent phosphorus content at 30 mg / L, and the ammonia nitrogen content at 40 mg / L, with the influent temperature also at room temperature. After 20 days of biofilm formation, all suspended sludge was discharged, and cultivation continued for another 5 days under the same conditions. A biofilm with a thickness of approximately 100 μm was formed on the suspended packing carrier, achieving a phosphorus removal rate of over 95.0%, a total nitrogen removal rate of 75–80%, and a COD removal rate of 75–85%.

[0056] Example 2

[0057] A method for simultaneously achieving phosphorus enrichment and nitrogen removal using carbon sources in urban wastewater includes the following steps:

[0058] a) Add municipal sewage to the biofilm reactor until the biofilm reactor is full; the biofilm reactor is filled with a suspended packing carrier with polyphosphate biofilm prepared in Example 1, and the filling amount accounts for 40.0% of the biofilm reactor capacity.

[0059] b) Stirring under anaerobic conditions allows the polyphosphate biofilm to release phosphorus from the organic carbon source in the wastewater;

[0060] c) A portion of the wastewater treated in step b) is discharged into a recovery tank for storage as recovery liquid;

[0061] d) Turn on the aeration device to perform aerobic aeration on the remaining wastewater in the biofilm reactor after the treatment in step b), so that the phosphorus in the wastewater is absorbed by the polyphosphate biofilm and the nitrogen in the wastewater is converted and removed by the polyphosphate biofilm.

[0062] e) Turn off the aeration device and discharge all the wastewater treated in step d) from the biofilm reactor;

[0063] f) Return the recovered liquid to the biofilm reactor to begin a new cycle from step (a);

[0064] Steps a) to f) constitute one operating cycle, during which the wastewater treated by the biofilm reactor in step d) of each operating cycle is continuously discharged; after multiple operating cycles, the phosphorus concentration of the recovered liquid in step c) reaches the phosphorus recovery process requirements, and a batch of phosphorus recovered liquid is obtained, thus completing one phosphorus concentration cycle.

[0065] In this embodiment, the urban wastewater has a COD of 350 mg / L, NH3-N of 50 mg / L, TP of 7 mg / L, and a temperature of 22.5°C. The volume ratio of the recovered liquid returned to the biofilm reactor in the previous operation cycle step f) to the wastewater entering the biofilm reactor in the next operation cycle step a) is 1:2.5. In step b), the anaerobic stirring speed is 75 rpm, and the anaerobic stirring time is 12 h. In step d), the dissolved oxygen content of the water body during the aerobic aeration treatment is controlled at 7 mg / L, and the aerobic aeration treatment time is 12 h.

[0066] In this embodiment, after completing 90 operation cycles of steps a) to f), water quality testing was performed, and the results are shown in Table 1:

[0067] Table 1 Water quality testing data from Example 2

[0068] project COD mg / L <![CDATA[NH3-Nmg / L]]> TP mg / L TN mg / L Influent to the biofilm reactor 350 50 7 50 Effluent from aerobic aeration treatment <30 - <0.5 <5 Recovery tank solution (phosphorus recovery solution) - - >85 -

[0069] As can be seen from the data in Table 1, after the wastewater passes through the biofilm reactor, the aerobic effluent quality meets the Class I standard requirements of GB18918-2002 "Discharge Standard of Pollutants for Urban Wastewater Treatment Plants", and the phosphorus concentration in the recovery tank is >85mg / L, which can meet the requirements of current phosphorus product processing technology.

[0070] Example 3

[0071] The method for simultaneously achieving phosphorus enrichment and denitrification using urban wastewater as a carbon source differs from Example 2 in that: the urban wastewater has a COD of 220 mg / L, NH3-N of 40 mg / L, TP of 5 mg / L, and a temperature of 26.1℃; the volume ratio of the recovered liquid returned to the biofilm reactor in the previous cycle step f) to the wastewater entering the biofilm reactor in the next cycle step a) is 1:1.5; the anaerobic stirring time in step b) is 6 h; and the aerobic aeration treatment time in step d) is 6 h.

[0072] In this embodiment, after completing 90 operation cycles of steps a) to f), water quality testing was performed, and the results are shown in Table 2:

[0073] Table 2 Water quality testing data from Example 3

[0074] project COD mg / L <![CDATA[NH3-Nmg / L]]> TP mg / L TN mg / L Influent to the biofilm reactor 220 40 5 40 Effluent from aerobic aeration treatment <20 - <0.5 <5 Recovery tank solution (phosphorus recovery solution) - - >75 -

[0075] As can be seen from the data in Table 2, after the wastewater passes through the biofilm reactor, the aerobic effluent meets the Class I standard requirements of GB18918-2002 "Discharge Standard of Pollutants for Urban Wastewater Treatment Plants", and the phosphorus concentration in the recovery tank is >75mg / L, which can meet the requirements of current phosphorus product processing technology.

[0076] Example 4

[0077] The method for simultaneously achieving phosphorus enrichment and denitrification using urban sewage carbon sources differs from Example 2 in that: the urban sewage has a COD of 160 mg / L, NH3-N of 30 mg / L, TP of 5 mg / L, and a temperature of 28.9℃; the volume ratio of the recovered liquid returned to the biofilm reactor in the previous operation cycle step f) to the sewage entering the biofilm reactor in the next operation cycle step a) is 1:1; the anaerobic stirring time in step b) is 2 h; and the aerobic aeration treatment time in step d) is 2 h.

[0078] In this embodiment, after completing 90 operation cycles of steps a) to f), water quality testing was performed, and the results are shown in Table 3:

[0079] Table 3 Water quality testing data from Example 4

[0080] project COD mg / L <![CDATA[NH3-Nmg / L]]> TP mg / L TN mg / L Influent to biofilm reactor 160 30 5 30 Effluent from aerobic aeration treatment <20 - <0.5 <5 Recovery tank solution (phosphorus recovery solution) - - >70 -

[0081] As can be seen from the data in Table 3, after the wastewater passes through the biofilm reactor, the aerobic effluent meets the Class I standard requirements of GB18918-2002 "Discharge Standard of Pollutants for Urban Wastewater Treatment Plants", and the phosphorus concentration in the recovery tank is >70mg / L, which can meet the requirements of current phosphorus product processing technology.

[0082] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for simultaneously achieving phosphorus enrichment and nitrogen removal using urban sewage carbon sources, characterized in that, Includes the following steps: a) A certain amount of urban sewage is added to the biofilm reactor; the biofilm reactor is filled with packing material, on which a polyphosphate biofilm is formed. The polyphosphate biofilm is formed by repeatedly alternating anaerobic and aerobic treatment of the packing material in a water body containing activated sludge; the influent COD during the anaerobic treatment is 200-300 mg / L; the dissolved oxygen content during the aerobic treatment is 6-8 mg / L, the influent phosphorus content is 20-40 mg / L, and the ammonia nitrogen content is 30-50 mg / L. b) Stirring under anaerobic conditions allows the polyphosphate biofilm to release phosphorus from the organic carbon source in the wastewater; c) A portion of the wastewater treated in step b) is discharged into a recovery tank for storage as recovery liquid; d) Turn on the aeration device to perform aerobic aeration on the remaining wastewater in the biofilm reactor after the treatment in step b), so that the phosphorus in the wastewater is absorbed by the polyphosphate biofilm and the nitrogen in the wastewater is converted and removed by the polyphosphate biofilm. e) Turn off the aeration device and discharge all the wastewater treated in step d) from the biofilm reactor; f) Return the recovered liquid to the biofilm reactor to begin a new cycle from step (a); Steps a) to f) constitute one operating cycle, during which the wastewater treated by the biofilm reactor in step d) of each operating cycle is continuously discharged; after multiple operating cycles, the phosphorus concentration of the recovered liquid in step c) reaches the phosphorus recovery process requirements, and a batch of phosphorus recovered liquid is obtained, thus completing one phosphorus concentration cycle.

2. The method according to claim 1, characterized in that, In step a), the duration of a single anaerobic treatment is 2-6 hours, the duration of a single aerobic treatment is 2-6 hours, and the total duration of repeated alternating anaerobic and aerobic treatments is 20-30 days.

3. The method according to claim 1, characterized in that, In step a), the thickness of the polyphosphorus biofilm is 80–150 μm.

4. The method according to claim 1, characterized in that, The volume ratio of the recovered liquid returned to the biofilm reactor in step f) of the previous operating cycle to the municipal wastewater entering the biofilm reactor in step a) of the next operating cycle is 1:(1 to 2.5).

5. The method according to claim 1, characterized in that, It also includes the following steps: Phosphorus in the phosphorus recovery solution is recovered by crystallization to obtain phosphorus products.

6. The method according to claim 1, characterized in that, In step a), the COD of the urban sewage is 150–400 mg / L.

7. The method according to claim 1, characterized in that, In step a), the ammonia nitrogen content of the urban sewage is 15-60 mg / L.

8. The method according to claim 1, characterized in that, In step a), the total phosphorus content of the urban sewage is 5-10 mg / L.

9. The method according to claim 1, characterized in that, In step b), the stirring time under anaerobic conditions is 2 to 12 hours.

10. The method according to claim 1, characterized in that, In step d), the dissolved oxygen content of the water body undergoing aerobic aeration treatment is 6-8 mg / L, and the treatment time is 2-12 h.