A method for reconstructing partial denitrification coupled with anaerobic ammonia oxidation in municipal wastewater treatment

Abstract

The application belongs to the technical field of urban sewage treatment, and discloses a partial denitrification coupled with anaerobic ammonia oxidation reconstruction method for urban sewage treatment, which is characterized in that a partial denitrification coupled with anaerobic ammonia oxidation system is arranged downstream of an original treatment system of an urban sewage treatment plant, and the flow rate of influent water entering the original treatment system and the partial denitrification coupled with anaerobic ammonia oxidation system is adjusted through the ratio of NO3 ‑ / NH4 + , so that the ratio of NO3 ‑ / NH4 + is within the optimal ratio range of 1.2-1.4 for anaerobic ammonia oxidation, the upgrading reconstruction of the existing urban sewage treatment plant is realized with minimum modification, the upgrading reconstruction period is shortened, and the engineering cost is saved.

Description

Technical Field

[0001] This application belongs to the field of urban wastewater treatment technology, specifically relating to a method for modifying a portion of urban wastewater treatment by coupling denitrification with anaerobic ammonia oxidation. Background Technology

[0002] Nitrogen is one of the basic pollutant removal targets in urban wastewater treatment plants. Most existing urban wastewater treatment plants employ traditional complete nitrification-denitrification biological nitrogen removal processes. Nitrogen transformation includes assimilation, ammonification, nitrification, and denitrification. However, the transformation process from combined nitrogen to gaseous nitrogen, thus fundamentally removing nitrogen pollutants, mainly involves nitrification and denitrification reactions. Nitrification is a biochemical reaction under aerobic conditions that oxidizes ammonia nitrogen to nitrite and nitrate nitrogen; denitrification refers to the reaction under anoxic conditions that reduces nitrite and nitrate nitrogen to gaseous nitrogen (N2) or N2O and NO, which can be basically represented as:

[0003] Nitrification reaction: NH4 + →NO2 - →NO3 - ;

[0004] Denitrification reaction: NO3 - →NO2 - →NO→N2O→N2;

[0005] However, aeration in the nitrification reaction consumes a large amount of energy, 1 mol NH4 + Oxidized to NO2 - It requires 1.5 mol of O2, which is oxidized to produce NO3. - 2.0 mol of O2 is required. In the denitrification reaction, 1 g of NO3 is denitrified. - Requires 2.86g of organic matter and 1g of denitrification NO2 - It requires 1.72g of organic matter, and N2O is a greenhouse gas that, like other greenhouse gases such as carbon dioxide and methane, affects the Earth's climate system. This has become a major problem facing wastewater treatment plants for nitrogen removal.

[0006] In recent years, anaerobic ammonia oxidation has been considered a promising solution, as it can be carried out through a fully autotrophic bacterial mechanism, with anaerobic ammonia oxidizing bacteria using NO2. - -N acts as an electron acceptor, directly oxidizing NH4. + -N, simultaneously converting both into nitrogen gas (N2), has advantages such as reducing carbon consumption, reducing sludge production, and reducing N2O emissions. In biological treatment systems, nitrification (NH4+) occurs in the aerobic zone. + →NO2 - →NO3 - In the anoxic zone, denitrification (NO3) occurs.- →NO2 - (NO → N2O → N2), but under steady conditions, NO2 is not produced in biological treatment systems. - -N accumulation, and will not interact with NH4 + -N exists in the same time and space, therefore research on the application of anaerobic ammonia oxidation technology in the treatment of actual wastewater is still limited.

[0007] Currently, with the increasing volume of domestic sewage and industrial wastewater, and continuously tightening discharge standards, and given that denitrification is a key challenge in the design and upgrading of urban sewage treatment processes, it has become a major problem facing sewage treatment plants in the context of the "dual-carbon" era. Upgrading existing urban sewage treatment plants is necessary, but current methods involve significant modifications, long construction periods, and high costs. Therefore, finding a way to achieve treatment requirements with minimal modifications while utilizing anaerobic ammonia oxidation technology is an important research direction. Summary of the Invention

[0008] The purpose of this application is to address the problems of the prior art by providing a method for modifying a portion of urban wastewater treatment by coupling denitrification with anaerobic ammonia oxidation.

[0009] To solve the technical problem, the technical solution of this application is: a method for modifying part of the denitrification coupled with anaerobic ammonia oxidation in urban wastewater treatment, comprising the following steps:

[0010] Step 1: Install a partial denitrification coupled with anaerobic ammonia oxidation system downstream of the existing treatment system of the urban wastewater treatment plant;

[0011] Step 2: Divide the total influent flow Q of the urban wastewater treatment plant into two parts. One part, q1, enters the original treatment system, and the other part, q2, enters the partial denitrification coupled anaerobic ammonium oxidation system.

[0012] Step 3: Based on the NO3 in the effluent from the existing treatment system - -N concentration and NH4+ in municipal wastewater treatment plant influent + The NO3- concentration is calculated based on the influent flow rate q1 entering the original treatment system and the influent flow rate q2 entering the partial denitrification coupled anaerobic ammonia oxidation system, so that NO3- - / NH4 + The ratio is within the optimal ratio range R;

[0013] Step 4: Mix the effluent from the original treatment system with part of the influent from the denitrification coupled anaerobic ammonium oxidation system to carry out anaerobic ammonium oxidation reaction, thereby realizing the transformation of the urban sewage treatment plant.

[0014] Preferably, the partial denitrification coupled anammox system in step 1 includes a partial denitrification coupled anammox reactor. The controlled temperature of the partial denitrification coupled anammox reactor is 25°C, the controlled rotation speed is 70 rpm, and each operating cycle of the partial denitrification coupled anammox reactor is 4 hours: including 5 minutes of influent, 190 minutes of stirring, 30 minutes of settling, 10 minutes of effluent, and 5 minutes of idle time. The volume exchange ratio of the partial denitrification coupled anammox reactor is 50%, and the filling rate of the anammox bacteria packing material in the partial denitrification coupled anammox reactor is 15%.

[0015] Preferably, in the construction of the partially denitrification coupled anaerobic ammonium oxidation reactor, the activated sludge is taken from the anoxic zone of a municipal wastewater treatment plant, and the MLSS is 2323±62 mg·L⁻¹. -1 MLVSS was 1713±34 mg·L. -1 The anaerobic ammonia oxidizing bacteria packing material was taken from a fixed-bed biofilm reactor, and the specific surface area of ​​the anaerobic ammonia oxidizing bacteria packing material was 500 m². 2 ·m -3 The nitrogen load was 0.39 mg NH4. + -N·(m 3 ∙d) -1 The maximum activity was 122.25 mg N·(L∙d). -1 .

[0016] Preferably, step 3 specifically comprises:

[0017] Step 3-1: Let NO3 - / NH4 + The optimal ratio range is for parameter R, and for NO3 in the effluent from the original treatment system of the municipal wastewater treatment plant. - When the -N concentration is a, the NH4+ in the influent of the municipal wastewater treatment plant... + If the N concentration is b, then NO3- enters the partial denitrification coupled anaerobic ammonium oxidation system. - -N and NH4 + The concentration of -N satisfies the following formula:

[0018] a=Rb;

[0019] Step 3-2: Assuming that all effluent from the original treatment system of the municipal wastewater treatment plant enters a partial denitrification coupled anaerobic ammonia oxidation system, then NO3... - The total N concentration is fa, where f is the ratio of the influent flow rate q1 to the total influent flow rate Q in the original treatment system; while the N2 concentration entering the partial denitrification coupled anaerobic ammonium oxidation system is... + The total concentration of -N is (1-f)b, then the following formula is obtained:

[0020] fa = R(1-f)b;

[0021] The following formula is obtained from the calculation:

[0022] ;

[0023] Step 3-3: When the total daily influent flow rate of the urban wastewater treatment plant is Q, the formula for calculating the influent flow rate q1 entering the existing treatment system is:

[0024] q1=fQ;

[0025] The following formula is obtained from the calculation:

[0026] ;

[0027] The formula for calculating the influent flow rate q2 entering the partial denitrification coupled anaerobic ammonia oxidation system is:

[0028] q2 = Q - q1;

[0029] The influent flow rate q1 entering the original treatment system and the influent flow rate q2 entering the partial denitrification coupled anaerobic ammonia oxidation system are obtained, and NO3 is reduced. - / NH4 + The ratio is within the optimal ratio range R.

[0030] Preferably, the parameter R is 1.2 to 1.4.

[0031] Preferably, after obtaining the influent flow rate q2 entering the partial denitrification coupled anaerobic ammonium oxidation system, the carbon source dosage W is calculated as follows:

[0032] Let COD total / TN inf The ratio is the parameter k, then the daily COD required by the partial denitrification coupled anaerobic ammonium oxidation system is... total The quantity is W 需 Then we get the following formula:

[0033] W 需 =kTN inf

[0034] Among them, the nitrogen source TN that enters part of the denitrification coupled anaerobic ammonia oxidation system daily inf The calculation formula is:

[0035] TN inf =(fa+(1-f)b)Q;

[0036] The formula for calculating the carbon source dosage W is:

[0037] W 实 =BOD(1-f)Q;

[0038] W=W 需 -W 实 ;

[0039] Wherein, BOD is the measured biochemical oxygen demand, mg·L -1 .

[0040] Preferably, the parameter k is 2.6 to 3.0.

[0041] Compared with the prior art, the advantages of this application are:

[0042] (1) This application discloses a method for modifying a partial denitrification coupled with anaerobic ammonium oxidation system in urban wastewater treatment. A partial denitrification coupled with anaerobic ammonium oxidation system is installed downstream of the existing treatment system in the urban wastewater treatment plant, and NO3 is used to... - / NH4 + The ratio was adjusted to control the influent flow rate into the existing treatment system and part of the denitrification coupled anaerobic ammonium oxidation system, so that NO3 - / NH4 + Anaerobic ammonia oxidation is carried out with the ratio of the two components within the optimal range of 1.2 to 1.4, which enables the upgrading and renovation of existing urban sewage treatment plants to achieve minimal changes, shorten the construction period of the upgrading and renovation, and save engineering costs.

[0043] (2) Without changing the original treatment system, this application directly mixes the effluent of the original treatment system with the influent of part of the denitrification coupled anaerobic ammonium oxidation system for anaerobic ammonium oxidation reaction. The influent of part of the denitrification coupled anaerobic ammonium oxidation system does not pass through the original biological system and does not participate in complete nitrification and denitrification. Therefore, it saves electricity and carbon source and greatly reduces the transformation cost.

[0044] (3) This application is based on the best NO3 - / NH4 + Ratio and COD total / TN inf The ratio, through partial denitrification coupled with an anaerobic ammonium oxidation system, achieves good nitrogen removal performance, does not require an external carbon source, and achieves cost reduction and efficiency improvement;

[0045] (4) This application uses a partial denitrification coupled with an anaerobic ammonia oxidation system to carry out the anaerobic ammonia oxidation reaction. It does not require aeration, achieves good nitrogen removal performance, greatly saves power consumption, and helps carbon neutrality. Attached Figure Description

[0046] Figure 1 This is a schematic diagram illustrating the modification of a partial denitrification coupled with anaerobic ammonia oxidation modification method for urban wastewater treatment according to this application;

[0047] Figure 2 A graph showing the typical periodic changes in nitrogen concentration, COD, and pH.

[0048] Figure 3 This diagram shows the nitrogen removal performance verification of a partial denitrification coupled with anaerobic ammonia oxidation modification method for urban wastewater treatment according to this application.

[0049] Figure 4 COD total / TN inf and TN eff Corresponding change diagram.

[0050] Explanation of reference numerals in the attached figures:

[0051] 1. Existing treatment system; 2. Partial denitrification coupled with anaerobic ammonia oxidation system. Detailed Implementation

[0052] The present application is described in detail below with reference to the accompanying drawings and specific embodiments, but the present application is not limited to these embodiments. The present application covers any alternatives, modifications, equivalent methods, and solutions made within the spirit and scope of the present application. To provide the public with a thorough understanding of the present application, specific details are described in detail in the following embodiments, but those skilled in the art will fully understand the present application even without these detailed descriptions.

[0053] This application provides a method for partially retrofitting urban wastewater treatment processes using denitrification coupled with anaerobic ammonia oxidation. This method achieves a total nitrogen (TN) concentration of ≤5 mg / L, meeting the TN discharge requirements of ≤15 mg / L in the "Shaanxi Province Integrated Wastewater Discharge Standard for the Yellow River Basin" (DB61 / 224-2018) and ≤12 mg / L in the Class IV surface water quality standard. It provides technical support and operable design parameters for urban wastewater treatment process design, upgrading, or future implementation of more stringent total nitrogen discharge requirements, achieving the goals of low-carbon, green, environmentally friendly, and sustainable development.

[0054] like Figure 1 As shown, this application discloses a method for modifying part of the denitrification coupled with anaerobic ammonia oxidation in urban wastewater treatment, including the following steps:

[0055] Step 1: Install a partial denitrification coupled anaerobic ammonia oxidation system 2 downstream of the existing treatment system 1 of the urban wastewater treatment plant;

[0056] Step 2: Divide the total influent flow Q of the urban wastewater treatment plant into two parts. One part, q1, enters the original treatment system 1, and the other part, q2, enters the partial denitrification coupled anaerobic ammonia oxidation system 2.

[0057] Step 3: Based on the NO3 in the effluent from the original treatment system 1 - -N concentration and NH4+ in municipal wastewater treatment plant influent +The NO3- concentration is calculated based on the influent flow rate q1 entering the original treatment system 1 and the influent flow rate q2 entering the partial denitrification coupled anaerobic ammonia oxidation system 2, so that NO3- - / NH4 + The ratio is within the optimal ratio range R;

[0058] Step 4: Mix the effluent from the original treatment system 1 with part of the influent from the denitrification coupled anaerobic ammonia oxidation system 2 to carry out anaerobic ammonia oxidation reaction, thereby realizing the transformation of the urban sewage treatment plant.

[0059] Preferably, the partial denitrification coupled anammox system 2 in step 1 includes a partial denitrification coupled anammox reactor. The controlled temperature of the partial denitrification coupled anammox reactor is 25°C, the controlled rotation speed is 70 rpm, and each operating cycle of the partial denitrification coupled anammox reactor is 4 hours: including 5 minutes of influent, 190 minutes of stirring, 30 minutes of settling, 10 minutes of effluent, and 5 minutes of idle time. The volume exchange ratio of the partial denitrification coupled anammox reactor is 50%, and the filling rate of the anammox bacteria packing material in the partial denitrification coupled anammox reactor is 15%.

[0060] Preferably, in the construction of the partially denitrification coupled anaerobic ammonium oxidation reactor, the activated sludge is taken from the anoxic zone of a municipal wastewater treatment plant, and the MLSS is 2323±62 mg·L⁻¹. -1 MLVSS was 1713±34 mg·L. -1 The anaerobic ammonia oxidizing bacteria packing material was taken from a fixed-bed biofilm reactor, and the specific surface area of ​​the anaerobic ammonia oxidizing bacteria packing material was 500 m². 2 ·m -3 The nitrogen load was 0.39 mg NH4. + -N·(m 3 ∙d) -1 The maximum activity was 122.25 mg N·(L∙d). -1 .

[0061] Preferably, step 3 specifically comprises:

[0062] Step 3-1: Let NO3 - / NH4 + The optimal ratio range is for parameter R, and the NO3 in the effluent of the original treatment system 1 of the urban wastewater treatment plant. - When the -N concentration is a, the NH4+ in the influent of the municipal wastewater treatment plant... + If the -N concentration is b, then NO3 enters the partial denitrification coupled anaerobic ammonium oxidation system 2. - -N and NH4 + The concentration of -N satisfies the following formula:

[0063] a=Rb;

[0064] Step 3-2: Assuming that all effluent from the original treatment system 1 of the municipal wastewater treatment plant enters the partial denitrification coupled anaerobic ammonia oxidation system 2, then NO3... - The total N concentration is fa, where f is the ratio of the influent flow rate q1 to the total influent flow rate Q entering the original treatment system 1; while the NH4+ entering the partial denitrification coupled anaerobic ammonium oxidation system 2... + The total concentration of -N is (1-f)b, then the following formula is obtained:

[0065] fa = R(1-f)b;

[0066] The following formula is obtained from the calculation:

[0067] ;

[0068] Step 3-3: When the total daily influent flow rate of the urban wastewater treatment plant is Q, the formula for calculating the influent flow rate q1 entering the original treatment system 1 is:

[0069] q1=fQ;

[0070] The following formula is obtained from the calculation:

[0071] ;

[0072] The formula for calculating the influent flow rate q2 entering the partial denitrification coupled anaerobic ammonia oxidation system 2 is as follows:

[0073] q2=(1-f)Q;

[0074] q2 = Q - q1;

[0075] The influent flow rate q1 entering the original treatment system 1 and the influent flow rate q2 entering the partial denitrification coupled anaerobic ammonia oxidation system 2 are obtained, and NO3 is reduced. - / NH4 + The ratio is within the optimal ratio range R.

[0076] Preferably, the parameter R is 1.2 to 1.4.

[0077] Preferably, after obtaining the influent flow rate q2 entering the partial denitrification coupled anaerobic ammonia oxidation system 2, the carbon source dosage W is calculated as follows:

[0078] Let COD total / TN inf The ratio is parameter k, then the daily COD required by the partial denitrification coupled anaerobic ammonium oxidation system 2 is... total The quantity is W 需 Then we get the following formula:

[0079] W 需=kTN inf

[0080] Among them, the nitrogen source TN that enters part of the denitrification coupled anaerobic ammonia oxidation system 2 daily inf The calculation formula is:

[0081] TN inf =(fa+(1-f)b)Q;

[0082] The formula for calculating the carbon source dosage W is:

[0083] W 实 =BOD(1-f)Q;

[0084] W=W 需 -W 实 ;

[0085] Wherein, BOD is the measured biochemical oxygen demand, mg·L -1 .

[0086] Preferably, the parameter k is 2.6 to 3.0.

[0087] This application discloses a method for modifying a portion of urban wastewater treatment processes by coupling denitrification with anaerobic ammonium oxidation, comprising three parts: the first part being the optimal NO3... - / NH4 + The first part is the determination of the ratio; the second part is the construction of a model for the partial denitrification coupled with anaerobic ammonia oxidation modification of urban sewage treatment; the third part is the experimental verification of the model.

[0088] (1) Best NO3 - / NH4 + ratio:

[0089] A partial denitrification coupled anaerobic ammonium oxidation (ANAO) reactor was constructed for laboratory use. This reactor, with an effective volume of 5 L, had been operating stably in the laboratory for two years. The experimental temperature was controlled at 25℃, and the constant-speed stirring system was operated at 70 rpm. Each reactor cycle lasted 4 hours, including 5 min of influent, 190 min of stirring, 30 min of settling, 10 min of effluent, and 5 min of idle time. The reactor's volume exchange ratio was 50%, and the ANAO packing material filling rate was 15%. The activated sludge used in the reactor construction was taken from the anoxic zone of the Ninth Wastewater Treatment Plant, with a MLSS of 2323 ± 62 mg·L⁻¹. -1 MLVSS was 1713±34 mg·L. -1 The anaerobic ammonia-oxidizing bacteria packing material was taken from a fixed-bed biofilm reactor that had been operating stably in the laboratory for two years. The packing material had a specific surface area of ​​500 m². 2 ·m -3 The nitrogen load was 0.39 mg NH4. + -N·(m3 ∙d) -1 The maximum activity was 122.25 mg N·(L∙d). -1 .

[0090] like Figure 2 The figure shown is a typical periodic graph of nitrogen concentration, COD, and pH value changes, representing the primary effluent from a municipal wastewater treatment plant (mainly containing NH4). + -N and organic matter) and secondary effluent (from the original treatment system, mainly containing NO3) - -N) was mixed in different proportions and fed into the reactor. After 90 days of long-term operation, the results showed that NO3- - / NH4 + The ratio is 1.2~1.4, COD total / TN inf With a ratio in the range of 2.6 to 3.0, the partial denitrification coupled with anaerobic ammonia oxidation modification method can achieve good denitrification effect on urban sewage.

[0091] (2) Construction of a model for partial denitrification coupled with anaerobic ammonia oxidation modification in urban wastewater treatment:

[0092] like Figure 1 As shown, the total influent flow rate Q (m³) of the urban wastewater treatment plant is... 3 ·d -1 It is divided into two parts. One part still uses the original processing system 1 (mostly traditional A / O or A). 2 / O process), the other part enters the partial denitrification coupled anaerobic ammonia oxidation system 2.

[0093] Assume the ratio of the influent flow rate q1 to the total influent flow rate Q in the original treatment system 1 is... f Then the flow rate entering the partial denitrification coupled anaerobic ammonium oxidation system 2 is (1- f );

[0094] Assuming the influent to the municipal wastewater treatment plant contains only NH4 + -N and organic matter; the effluent from the original treatment system 1 only contained NO3. - -N (secondary effluent COD is considered a non-biodegradable COD and can be ignored). The design involves mixing the effluent from the original treatment system 1 with the wastewater from the partially denitrified coupled anaerobic ammonia oxidation system 2 to provide NO3 for the partial denitrification process. - -N;

[0095] 1) Let NO3 - / NH4 + The optimal ratio range is for parameter R (R = 1.2~1.4); NO3 in the effluent of the original treatment system 1 - -N concentration is aNH4 in the influent of urban sewage treatment plants + If the -N concentration is b, then NO3 enters the partial denitrification coupled anaerobic ammonium oxidation system 2. - -N and NH4 + The concentration of -N satisfies the following formula (1):

[0096] a=Rb (1)

[0097] Assuming that all the effluent from the original treatment system 1 enters the partial denitrification coupled anaerobic ammonia oxidation system 2, then NO3 - The -N concentration is fa; while the NH4+ entering the partial denitrification coupled anaerobic ammonium oxidation system 2... + If the -N concentration is (1-f)b, then formula (2) can be obtained:

[0098] fa = R(1-f)b (2;

[0099] Formula (3) is obtained from the calculation:

[0100] (3);

[0101] When the total daily influent flow rate of the urban sewage treatment plant is Q (m³) 3 ·d -1 When ), the influent flow rate q1 entering the original treatment system 1 is calculated using the formula (4):

[0102] q1=fQ;

[0103] (4);

[0104] The formula for calculating the influent flow rate q2 entering the partial denitrification coupled anaerobic ammonia oxidation system 2 is (5):

[0105] q2 = Q - q1 (5);

[0106] 2) Let COD total / TN inf The ratio is parameter k (k=2.6~3.0), then the daily COD required by the partial denitrification coupled anaerobic ammonium oxidation system 2 is... total The quantity is W 需 Formula (6) can be obtained:

[0107] W 需 =kTN inf (6);

[0108] For typical urban wastewater treatment plants, the nitrogen source TN entering part of the denitrification coupled anaerobic ammonia oxidation system 2 daily... inf The calculation formula is (7):

[0109] TNinf =(fa+(1-f)b)Q (7;

[0110] The formula for calculating the carbon source dosage W is (8):

[0111] W 实 =BOD(1-f)Q;

[0112] W=W 需 -W 实 (8);

[0113] Wherein, BOD is the measured biochemical oxygen demand, mg·L -1 .

[0114] (3) Model experimental verification:

[0115] To verify the obtained optimal ratio range (NO3) - / NH4 + The ratio is 1.2~1.4, COD total / TN inf The ratio was 2.6 to 3.0. The experiment was designed within this range to verify that the water sample was taken from the High-tech Second Wastewater Treatment Plant.

[0116] The maximum influent total nitrogen (TN) of the High-tech Zone No. 2 Wastewater Treatment Plant during 2018-2019 was 41 mg·L⁻¹. -1 The average value was 24.64 mg·L. -1 NH4 + The maximum value of -N is 24.9 mg·L. -1 The average value was 9.29 mg·L⁻¹ -1 NO3 - / NH4 + Approximately 1.58~1.80, actual NO3 - / NH4 + The ratio should be lower than this range. The total nitrogen in the influent of the High-tech Zone's Second Wastewater Treatment Plant is not primarily composed of NH4+. + The -N form exists because its influent comes from wastewater from the Samsung Electronics industrial park (containing high levels of NO3). - -N) and a small amount of domestic sewage (containing a small amount of NH4) + The influent to the water treatment plant is composed of a mixture of nitrogen (N) and organic matter, thus containing a portion of the reaction substrate required for the denitrification coupled anaerobic ammonium oxidation (ANAO) process. Therefore, the entire influent to this water treatment plant can enter the reactor of the partial denitrification coupled ANAO system 2, where f=0. However, the influent to this water treatment plant is relatively low in domestic sewage, with a COD5 / TN ratio of approximately 1.14~1.42, and severely insufficient biodegradable organic matter to meet the requirements of denitrification. Therefore, the water treatment plant selected sodium acetate as an external carbon source, resulting in a daily C / N ratio exceeding 5.

[0117] During the verification period, the average influent NO3 of the Second Wastewater Treatment Plant in the High-tech Zone - -N, NH4 + -N concentration was 16.67 ± 0.51 mg⋅L -1 12.14 ± 0.48 mg⋅L -1 NO3 - / NH4 + Within the range of 1.3 to 1.4, it falls within the optimal ratio range (NO3). - / NH4 + (1.2~1.4).

[0118] Figure 3 This diagram shows the nitrogen removal performance verification of a partial denitrification coupled with anaerobic ammonia oxidation modification method for urban wastewater treatment, as described in this application. It verifies the nitrogen removal performance of the influent from the Second Wastewater Treatment Plant in the High-tech Zone; the average effluent NO3... - -N, NH4 + The concentrations of -N and TN were 3.76 ± 0.53 mg⋅L, respectively. -1 0.34±0.21mg⋅L -1 4.39±0.95 mg⋅L -1 The average effluent NRR, ARR, and TNRR were 77.09±1.03%, 97.34±1.64%, and 84.73±1.77%, respectively, indicating good nitrogen removal performance.

[0119] Figure 4 COD total / TN inf and TN eff The corresponding change graph shows that because the proportion of domestic sewage in the influent of the High-tech Zone's Second Wastewater Treatment Plant is relatively small, the required amount of external carbon source is relatively high, which verifies the COD. total / TN inf When the ratio is 2.8 to 3.0, it falls within the optimal ratio range (COD). total / TN inf (At a concentration of 2.6~3.0), the NO3 in the effluent can be reduced. - -N concentration less than 5 mg·L -1 The following calculations using the model formula (8) show that the wastewater treatment plant can save at least 40% to 44% of the daily carbon source addition.

[0120] Furthermore, this application, through verification of actual wastewater from the Xi'an No. 9 Wastewater Treatment Plant, found that the q1:q2 flow ratio was 5:1, meaning that in NO3... - / NH4 +The ratio is 1.2~1.4, and the C / T ratio is 2.6~3.0; with a hydraulic retention time of 8h, TN ≤ 3mg / L; with a hydraulic retention time of 4h, TN ≤ 5mg / L; and with a hydraulic retention time of 2h, TN ≤ 8mg / L. The effluent TN standard is far higher than the Class IV water quality standard with a maximum TN value of 12mg / L. It can be applied to more stringent TN upgrades, as well as to sewage treatment projects in township enterprises, small sewage treatment plants, and river management where TN removal is required.

[0121] This application discloses a method for retrofitting a municipal wastewater treatment plant with partial denitrification coupled with anaerobic ammonium oxidation. The method involves installing a partial denitrification coupled with anaerobic ammonium oxidation system downstream of the existing treatment system in the municipal wastewater treatment plant, and using NO3... - / NH4 + The ratio was adjusted to control the influent flow rate into the existing treatment system and part of the denitrification coupled anaerobic ammonium oxidation system, so that NO3 - / NH4 + When the ratio is within the optimal range of 1.2 to 1.4, anaerobic ammonia oxidation can be carried out, minimizing the modifications required for upgrading existing urban wastewater treatment plants, shortening the upgrading period, and saving project costs.

[0122] This application directly mixes the effluent from the original treatment system with part of the influent from the denitrification coupled anaerobic ammonium oxidation system without changing the original treatment system, and carries out the anaerobic ammonium oxidation reaction. The influent from the denitrification coupled anaerobic ammonium oxidation system does not pass through the original biological system and does not participate in complete nitrification and denitrification, thus saving power consumption and carbon source and greatly reducing the transformation cost.

[0123] This application is based on the best NO3 - / NH4 + Ratio and COD total / TN inf The ratio, through partial denitrification coupled with an anaerobic ammonium oxidation system, achieves good nitrogen removal performance, without the need for an external carbon source, thus reducing costs and increasing efficiency.

[0124] This application utilizes a partial denitrification coupled with an anaerobic ammonium oxidation system to perform anaerobic ammonium oxidation, eliminating the need for aeration, achieving excellent nitrogen removal performance, significantly saving power consumption, and contributing to carbon neutrality.

[0125] The preferred embodiments of this application have been described in detail above. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application.

[0126] Many other changes and modifications can be made without departing from the concept and scope of this application. It should be understood that this application is not limited to the specific embodiments, and the scope of this application is defined by the appended claims.

Claims

1. A method for upgrading municipal wastewater treatment by partial denitrification coupled with anaerobic ammonia oxidation, characterized in that, Comprise the following steps: Step 1: Set part denitrification coupled anaerobic ammonia oxidation system (2) downstream of the original treatment system (1) of the municipal wastewater treatment plant; The partial denitrification coupled anaerobic ammonia oxidation system (2) comprises a partial denitrification coupled anaerobic ammonia oxidation reactor, the control temperature of the partial denitrification coupled anaerobic ammonia oxidation reactor is 25 DEG C, the control rotating speed is 70 r / min, each operation period of the partial denitrification coupled anaerobic ammonia oxidation reactor is 4 hours: including 5 min water inlet, 190 min stirring, 30 min sedimentation, 10 min water outlet, 5 min idle, the volume exchange ratio of the partial denitrification coupled anaerobic ammonia oxidation reactor is 50%, the filling rate of anaerobic ammonia oxidation bacteria filler in the partial denitrification coupled anaerobic ammonia oxidation reactor is 15%; when the partial denitrification coupled anaerobic ammonia oxidation reactor is constructed, activated sludge is taken from the anoxic zone of a municipal wastewater treatment plant, MLSS is 2323±62 mg·L -1 , MLVSS is 1713±34 mg·L -1 , anaerobic ammonia oxidation bacteria filler is taken from a fixed bed biofilm reactor, the specific surface area of the anaerobic ammonia oxidation bacteria filler is 500 m 2 ·m -3 , nitrogen load is 0.39 mgNH4 + -N·(m 3 ·d) -1 , maximum activity is 122.25 mgN·(L·d) -1 ; Step 2: The total flow Q of the influent of the municipal wastewater treatment plant is divided into two parts, one part of the influent flow q1 enters the original treatment system (1), and the other part of the influent flow q2 enters the part denitrification coupled anaerobic ammonia oxidation system (2); Step 3: According to the NO3 - -N concentration in the effluent of the original treatment system (1) and the NH4 + -N concentration in the influent of the municipal wastewater treatment plant, the influent flow rate q1 entering the original treatment system (1) and the influent flow rate q2 entering the partial denitrification coupled ANAMMOX system (2) are calculated, so that the ratio of NO3 - / NH4 + is within the optimal ratio range R; Step 3-1: Set NO3 - / NH4 + The best ratio range of parameters R, NO3 - -N concentration a, NH4 + -N concentration b, then the NO3 - -N and NH4 + The concentration of NO3 -N and NH4 -N satisfies the following formula: a=Rb; Step 3-2: Assuming that all the effluent of the original treatment system (1) of the municipal wastewater treatment plant enters the partial denitrification coupled with ANAMMOX system (2), the NO3 - The total concentration of NH4-N is fa, and f is the ratio of the influent flow rate q1 of the original treatment system (1) to the total influent flow rate Q; and the NH4 + The total concentration of NH4-N is (1-f)b, and the following formula is obtained: fa=R(1-f)b; The following formula is calculated: ； Step 3-3: When the total flow Q of the daily influent of the municipal wastewater treatment plant is Q, the influent flow q1 entering the original treatment system (1) is calculated as follows: q1=fQ; The following formula is calculated: ； Then the influent flow q2 entering the part denitrification coupled anaerobic ammonia oxidation system (2) is calculated as follows: q2=Q-q1; The water inflow q1 into the original treatment system (1) and the water inflow q2 into the partial denitrification coupled ANAMMOX system (2) are obtained, and the ratio of NO3 - / NH4 + is within the optimal ratio range R, and the parameter R = 1.3-1.

4. After obtaining the influent flow q2 entering the part denitrification coupled anaerobic ammonia oxidation system (2), the carbon source dosage W is calculated, and the specific calculation is as follows: Let COD total / TN inf The ratio is parameter k, and the parameter k=2.6~3.0; the daily required COD of the partial denitrification coupled anaerobic ammonia oxidation system (2) is W total The amount of W 需 The following formula is obtained: W 需 =kTN inf Wherein, the nitrogen source TN entering the partial denitrification coupled with anaerobic ammonia oxidation system (2) per day inf The calculation formula is: TN inf = (fa+ (1-f)b) Q; The carbon source dosage W is calculated as follows: W 实 = BOD (1 - f) Q; W = W 需 W = W 实 ; Wherein, BOD is the measured biochemical oxygen demand, mg·L -1 ; Step 4: Mix the effluent of the original treatment system (1) and the influent of the part denitrification coupled anaerobic ammonia oxidation system (2) to carry out anaerobic ammonia oxidation reaction, so as to realize the transformation of the municipal wastewater treatment plant.

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