Device and process for enhanced nitrogen and phosphorus removal by using side-flow mud membrane composite to enhance utilization of internal carbon source

Abstract

The application discloses a side-flow mud film composite enhanced internal carbon source utilization enhanced denitrification and phosphorus removal device, which comprises an SBR reactor, the bottom of the SBR reactor is connected with the top of a side-flow anaerobic tank through a peristaltic pump III, the bottom of the side-flow anaerobic tank is connected with the top of the SBR reactor through a peristaltic pump II, the top and the bottom of the SBR reactor are respectively connected with a peristaltic pump I and a peristaltic pump IV, which are respectively used as an inlet water pump and an outlet water pump, and the SBR reactor, the side-flow anaerobic tank, the peristaltic pump I, the peristaltic pump II, the peristaltic pump III, the peristaltic pump IV and the controller are connected. The application further discloses a side-flow mud film composite enhanced internal carbon source utilization enhanced denitrification and phosphorus removal process, and the device and the process disclosed by the application solve the problem of poor acid production capacity of a side-flow reactor under low-temperature conditions in the prior art.

Description

Technical Field

[0001] This invention belongs to the technical field of wastewater biological treatment methods, specifically relating to an enhanced denitrification and phosphorus removal device that utilizes internal carbon sources through a side-flow sludge membrane composite enhancement, and also relating to an enhanced denitrification and phosphorus removal process that utilizes internal carbon sources through a side-flow sludge membrane composite enhancement. Background Technology

[0002] The rapid development of human society has led to the discharge of large amounts of agricultural, industrial, and domestic wastewater, making eutrophication a growing problem of water pollution. Among these issues, the discharge of nitrogen and phosphorus nutrients is the main cause of eutrophication in receiving water bodies.

[0003] Chemical and biological methods are currently the most common methods for phosphorus removal. Among them, chemical phosphorus removal (CPR) involves adding chemical agents such as iron salts and aluminum salts to react with PO4 in wastewater. 3- -P forms insoluble chemical precipitates, which are then removed; Biological Phosphorus Removal (BPR) utilizes the characteristics of polyphosphate-accumulating bacteria to release phosphorus anaerobically and absorb phosphorus excessively aerobically by discharging phosphorus-containing residual sludge at the end of the aerobic process to remove phosphorus from wastewater. In actual operation, the process usually needs to ensure sufficient carbon source (mainly volatile fatty acids (VFAs)) to achieve good phosphorus removal effect.

[0004] However, many wastewater treatment plants suffer from insufficient influent carbon sources. Adding commercial carbon sources and chemical phosphorus removal agents to improve phosphorus removal efficiency results in high operating costs and a long carbon footprint. Although the S2EBPR process can supplement the main reactor with some additional carbon sources through the side-flow anaerobic fermentation tank, the acid production capacity of the side-flow anaerobic fermentation tank and the nitrogen and phosphorus removal performance of the main reactor under low temperature conditions still need further optimization. Summary of the Invention

[0005] The first objective of this invention is to provide an enhanced denitrification and phosphorus removal device that utilizes internal carbon sources through a side-flow mud film composite, which solves the problem of poor acid production capacity of the side-flow reactor under low-temperature conditions in existing processes.

[0006] The second objective of this invention is to provide an enhanced denitrification and phosphorus removal process that utilizes internal carbon sources through a side-flow mud film composite enhancement.

[0007] The first technical solution adopted in this invention is: a side-flow mud film composite enhanced internal carbon source utilization enhanced denitrification and phosphorus removal device, including an SBR reactor, the bottom of the SBR reactor is connected to the top of the side-flow anaerobic tank through peristaltic pump III, the bottom of the side-flow anaerobic tank is connected to the top of the SBR reactor through peristaltic pump II, peristaltic pump I and peristaltic pump IV are respectively connected to the top and bottom of the SBR reactor, which serve as influent pump and effluent pump respectively, and the SBR reactor, the side-flow anaerobic tank, peristaltic pump I, peristaltic pump II, peristaltic pump III and peristaltic pump IV are all connected to a controller.

[0008] The first technical solution adopted in this invention is further characterized by:

[0009] Furthermore, the enhanced denitrification and phosphorus removal device, which utilizes the internal carbon source through a side-flow mud film composite, has an agitator installed inside the SBR reactor.

[0010] Furthermore, a stirrer is installed inside the bypass anaerobic tank.

[0011] The second technical solution adopted in this invention is: a side-flow mud film composite enhanced internal carbon source utilization enhanced denitrification and phosphorus removal process, using the aforementioned side-flow segmented influent enhanced acid production enhanced biological phosphorus removal device, specifically implemented according to the following steps:

[0012] Step 1: The raw sewage is pumped into the SBR reactor in stages using peristaltic pump I and held at 15℃-30℃ for 6 hours;

[0013] Step 2: The supernatant after sedimentation in Step 1 is directly discharged out of the system via peristaltic pump IV. Part of the remaining sludge is discharged out of the system through the sludge discharge port at the bottom of the SBR reactor. The other part of the sludge is stirred and then used as return sludge, which enters the top of the bypass anaerobic tank through the bottom opening of the SBR reactor via peristaltic pump III.

[0014] Step 3 and Step 2's returned sludge undergoes anaerobic fermentation and polyphosphate-accumulating bacteria screening in the bypass anaerobic tank, and is then returned to the SBR reactor via peristaltic pump II.

[0015] Step 4: Pass raw wastewater into the SBR reactor and repeat steps 2 and 3 to perform biological phosphorus removal from the raw wastewater.

[0016] The second technical solution adopted in this invention is further characterized by:

[0017] Furthermore, the sludge retention time in the system is 17 days.

[0018] Furthermore, the SBR reactor adopts a segmented influent multi-stage A / O operation mode.

[0019] Furthermore, the SBR reactor is divided into two anaerobic sections: the first anaerobic section and the second anaerobic section. The first anaerobic section receives half of the total amount of water, with an anaerobic time of 60 minutes and an aerobic time of 90 minutes. The second anaerobic section receives half of the total amount of water, with an anaerobic time of 60 minutes and an aerobic time of 90 minutes. The sedimentation time is 30 minutes, the drainage time is 25 minutes, and the water is fed into the side-flow anaerobic tank under stirring for 5 minutes.

[0020] Furthermore, in step 2, the sludge bypass ratio entering the bypass anaerobic tank is 20%.

[0021] Furthermore, in step 3, the hydraulic retention time of the returned sludge in the side-flow anaerobic tank is 96 h, the dissolved oxygen concentration is 0.01-0.1 mg / L, and the sludge concentration is 5800 mg / L.

[0022] Furthermore, a biofilm carrier, specifically anaerobic biological carrier AMC, is added inside the side flow anaerobic tank, with a filling ratio of 25%.

[0023] The beneficial effects of this invention are:

[0024] The SBR reactor of this invention adopts a segmented influent multi-stage A / O operation mode to make full use of carbon sources and improve denitrification efficiency.

[0025] The deep anaerobic conditions of the bypass anaerobic tank of the present invention create favorable conditions for polyphosphate-accumulating bacteria to gain an advantage in competition with polysaccharide-accumulating bacteria, thereby enhancing the phosphorus removal performance of the process.

[0026] The biofilm carrier added to the side-flow anaerobic tank of this invention increases the biomass per unit volume, enriches fermentation-capable microorganisms, and increases VFAs production. VFAs and other organic matter enter the main reactor, supplementing the carbon source required by denitrifying bacteria and polyphosphate-accumulating bacteria in the main reactor, thereby improving the overall nitrogen and phosphorus removal performance and system stability of the process.

[0027] The process structure of this invention is simple and flexible, and it is easy to combine and modify with the existing SBR process.

[0028] The residual sludge from the anaerobic fermentation section of the bypass anaerobic tank of the present invention has a certain sludge reduction effect. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the enhanced biological phosphorus removal device with bypass-flow segmented water inlet for enhanced acid production according to the present invention.

[0030] Figure 2 These are schematic diagrams illustrating the TP removal effect in Examples 1-6 of the present invention;

[0031] Figure 3 These are schematic diagrams illustrating the COD removal effects in Examples 1-6 of the present invention;

[0032] Figure 4 This is a schematic diagram of the TN removal effect in Examples 1-6 of the present invention.

[0033] In the diagram: 1. SBR reactor, 2. Controller, 3. Bypass anaerobic tank, 4-1. Peristaltic pump I, 4-2. Peristaltic pump II, 4-3. Peristaltic pump III, 4-4. Peristaltic pump IV. Detailed Implementation

[0034] The technical solution of the present invention will now be clearly and completely described in conjunction with the accompanying drawings.

[0035] This invention provides an enhanced denitrification and phosphorus removal device that utilizes a side-flow mud film composite to strengthen the internal carbon source, such as... Figure 1 As shown, the system includes an SBR reactor 1. The bottom of the SBR reactor 1 is connected to the top of the bypass anaerobic tank 3 via a peristaltic pump Ⅲ4-3. The bottom of the bypass anaerobic tank 3 is connected to the top of the SBR reactor 1 via a peristaltic pump Ⅱ4-2. The top and bottom of the SBR reactor 1 are respectively connected to peristaltic pump Ⅰ4-1 and peristaltic pump Ⅳ4-4, which serve as the influent pump and the effluent pump, respectively. The SBR reactor 1, the bypass anaerobic tank 3, peristaltic pump Ⅰ4-1, peristaltic pump Ⅱ4-2, peristaltic pump Ⅲ4-3, and peristaltic pump Ⅳ4-4 are all connected to the controller 2.

[0036] Both the SBR reactor 1 and the bypass anaerobic tank 3 are equipped with agitators.

[0037] The functions of each part are as follows:

[0038] SBR reactor 1:

[0039] SBR reactor 1 operates in a multi-stage influent, multi-stage A / O mode. Specifically, the first stage involves half of the total anaerobic influent, with an anaerobic time of 60 min and an aerobic time of 90 min; the second stage involves half of the total anaerobic influent, with an anaerobic time of 60 min and an aerobic time of 90 min; sedimentation time is 30 min; drainage time is 25 min; and the reactor then feeds water into the side-flow anaerobic tank 3 for 5 min while stirring.

[0040] The first anaerobic stage primarily removes residual nitrates from the influent and the reactor at the end of the previous operating cycle through denitrification. The chemical oxygen demand (COD) in the influent and the side-stream fermentation broth provides ample nutrients for denitrification, while also providing nutrients for polyphosphate-accumulating bacteria to synthesize PO4 from the water in the aerobic stage. 3- -P carbon energy storage material PHA provides carbon source;

[0041] The first aerobic stage activates the aeration device to provide sufficient dissolved oxygen for aerobic microorganisms and adequate contact with activated sludge, degrading organic pollutants and further utilizing and consuming COD. Nitrification oxidizes nitrates from the influent, side-flow fermentation broth, and residual ammonia nitrogen in the reactor from the previous operating cycle. Polyphosphate-accumulating bacteria absorb PO4 from the wastewater. 3- -P is stored in cells as polyphosphate, thus forming phosphorus-rich activated sludge.

[0042] The second anaerobic stage primarily removes nitrates from the influent and the first aerobic stage through denitrification. The chemical oxygen demand (COD) in the influent provides nutrients for denitrification and simultaneously allows polyphosphate-accumulating bacteria to synthesize PO4, which is then absorbed in excess from the water by the second aerobic stage. 3- The carbon energy storage material PHA provides the carbon source, and in the early stage of the second anaerobic stage, a large amount of NO3 is present. - -N acts as an electron acceptor, creating an oxygen-deficient environment within the reactor, thus allowing denitrifying polyphosphate-accumulating bacteria to absorb phosphorus simultaneously.

[0043] The second aerobic stage restarts the aeration device to provide sufficient dissolved oxygen for aerobic microorganisms and adequate contact with activated sludge, thereby degrading organic pollutants and further utilizing and consuming COD.

[0044] Nitrification removes residual ammonia nitrogen and nitrate from the influent and reactor at the end of the previous operating cycle; polyphosphate-accumulating bacteria absorb PO4 from the wastewater. 3- -P is stored in cells as polyphosphate, thus forming phosphorus-rich activated sludge;

[0045] After the reaction is completed, sedimentation is used to separate the sludge from the water, making the effluent clear. Some of the remaining concentrated phosphorus-containing sludge is discharged from the system to achieve biological phosphorus removal. After the drainage is completed, the stirring device is started to flow a certain amount of mixed sludge into the side flow anaerobic tank for anaerobic fermentation and phosphorus release.

[0046] Side-flow anaerobic tank 3: The dissolved oxygen in this reaction zone is generally zero. The inflow of aerobic nitrification liquid may cause a temporary increase in dissolved oxygen, but it will not affect the overall anaerobic environment. Under its deep anaerobic environment, sludge hydrolysis and fermentation produce additional VFAs. Polyphosphate-accumulating bacteria absorb VFAs and other usable carbon sources and assimilate them into intracellular carbon energy storage substances (PHA). This stores the necessary carbon source and energy for subsequent aerobic over-absorption of phosphorus. Under anaerobic conditions, polyphosphate-accumulating bacteria provide the energy required for life metabolism through the hydrolysis of intracellular polyphosphates and glycolysis. The phosphates produced by hydrolysis will diffuse to the extracellular space, increasing the phosphorus concentration.

[0047] This invention also provides an enhanced biological phosphorus removal process with bypass-flow segmented influent to enhance acid production, as detailed below:

[0048] Step 1: Raw wastewater enters SBR reactor 1. The raw wastewater has a COD of 300 mg / L, a total nitrogen (TN) of 30 mg / L, a total phosphorus (TP) of 9 mg / L, a water temperature of 19℃, a hydraulic retention time (HRT) of 6h, a dissolved oxygen concentration of 2.0-4.5 mg / L in the aerobic section, and a sludge concentration of 2700 mg / L.

[0049] Step 2: After the influent reaction in SBR reactor 1 is completed and sedimentation lasts for 30 minutes, the discharge is divided into two parts: wastewater and sludge. The supernatant is directly discharged out of the system, and part of the remaining sludge is discharged out of the system through the sludge discharge port at the bottom of SBR reactor 1 to achieve biological phosphorus removal. The sludge retention time (SRT) is 17 days. The other part of the sludge, after being stirred, enters the top of the bypass anaerobic tank 3 through the bottom opening of SBR reactor 1 via peristaltic pump Ⅲ4.3, with a bypass ratio of 20%.

[0050] Step 3: The returned sludge undergoes anaerobic fermentation and polyphosphate-accumulating bacteria screening in the bypass anaerobic tank 3, and then is returned to the first anaerobic section of the SBR reactor 1. The HRT of the bypass anaerobic tank is 96 h, the dissolved oxygen concentration is 0.01-0.1 mg / L, and the sludge concentration is 5800 mg / L.

[0051] The influent and bypass anaerobic tank 3, along with the fermentation and sludge mixing tank, provide a carbon source for denitrifying bacteria and polyphosphate-accumulating bacteria in the first anaerobic stage. This removes nitrates from the influent and residual nitrates from the previous operating cycle, achieving denitrification. Simultaneously, it provides a source for polyphosphate-accumulating bacteria to synthesize PO4 for the aerobic stage, allowing them to absorb excess PO4 from the water. 3 The carbon source for the -P carbon energy storage substance, polyhydroxyalkanoates (PHA), is provided. In the first aerobic stage, heterotrophic microorganisms further decompose organic matter, while polyphosphate-accumulating bacteria consume internal carbon sources and excessively absorb phosphorus from the water. Simultaneously, ammonia nitrogen is converted to nitrate nitrogen by nitrifying bacteria. In the second anaerobic stage, the influent provides a carbon source for denitrifying bacteria and polyphosphate-accumulating bacteria, removing nitrates produced in the first aerobic stage. Simultaneously, polyphosphate-accumulating bacteria synthesize the carbon energy storage substance PHA. Initially, the second anaerobic stage is affected by the presence of large amounts of NO3. - -N acts as an electron acceptor, creating an anoxic environment within the reactor, allowing denitrifying polyphosphate-accumulating bacteria to simultaneously absorb phosphorus; the second aerobic stage converts the remaining ammonia nitrogen from the previous operating stage into NO3 through nitrification. - -N, while polyphosphate-accumulating bacteria consume internal carbon sources to excessively absorb phosphorus from the water, forming phosphorus-containing sludge. Through sedimentation and sludge discharge, phosphorus is discharged outside the system, achieving the purpose of phosphorus removal; some sludge flows to the side anaerobic tank 3, where it undergoes hydrolysis and fermentation under deep anaerobic conditions to produce acid, and after screening and acclimation of polyphosphate-accumulating bacteria, it is returned to the main flow first anaerobic section. After measuring and analyzing the effluent quality, it can be concluded that: the COD removal rate reaches 89.88±3.81%, and 92.86% of the effluent COD can meet or exceed the Class A discharge standard (COD concentration <50 mg / L); absorption of PO4 3--P removal rate reached 90.94±4.53%, demonstrating strong phosphorus removal performance; NH4 + -N removal rate reached 97.26±2.76%, and 71.43% of NH4 in the effluent was removed. + -N is below 1.0 mg / L, meeting the Class III surface water standard, with 50.0% of the effluent containing NH4+. + -N was less than 0.5 mg / L, meeting the Class II surface water standard; TN removal rate reached 74.51±4.25%, with 92.86% of the effluent TN less than 10 mg / L.

[0052] The compositions of the present invention will be further described below with reference to examples and accompanying drawings.

[0053] Example 1

[0054] Step 1: Raw wastewater enters SBR reactor 1. The raw wastewater has a COD of 300 mg / L, TN of 30 mg / L, TP of 9 mg / L, a water temperature of 19℃, an HRT of 6h, a dissolved oxygen concentration of greater than 2.0 mg / L in the aerobic section, and a sludge concentration of 2700 mg / L.

[0055] Step 2: After the influent reaction of SBR reactor 1 is completed and sedimentation lasts for 30 minutes, the discharge is divided into two parts: wastewater and sludge. The supernatant is directly discharged out of the system, and part of the remaining sludge is discharged out of the system through the sludge discharge port at the bottom of SBR reactor 1 to achieve biological phosphorus removal. The SRT is 17 days. The other part of the sludge, after being stirred, enters the top of the bypass anaerobic tank 3 through the bottom opening of SBR reactor 1 via peristaltic pump Ⅲ4.3. The bypass ratio is 20%. The bypass anaerobic tank 3 is filled with a biofilm carrier, specifically anaerobic biological carrier AMC, with a filling ratio of 25%.

[0056] Step 3: The returned sludge undergoes anaerobic fermentation and polyphosphate-accumulating bacteria screening in the bypass anaerobic tank 3, and then is returned to the first anaerobic section of the SBR reactor 1. The HRT of the bypass anaerobic tank is 96h, the dissolved oxygen concentration is less than 0.1mg / L, and the sludge concentration is 5800mg / L.

[0057] The final effluent indicators are: COD=18.9mg / L, TN=6.4mg / L, TP=0.4mg / L. All indicators meet the Class A discharge standard stipulated in the "Standard for Pollutant Discharge Indicators of Urban Wastewater Treatment Plants (GB18918-2002)".

[0058] Example 2

[0059] Step 1: Raw wastewater enters SBR reactor 1. The raw wastewater has a COD of 290 mg / L, TN of 27 mg / L, TP of 8 mg / L, a water temperature of 30℃, a hydraulic retention time (HRT) of 6 h, a dissolved oxygen concentration of greater than 2.0 mg / L in the aerobic section, and a sludge concentration of 2600 mg / L.

[0060] Step 2: After the influent reaction of SBR reactor 1 is completed and sedimentation lasts for 30 minutes, the discharge is divided into two parts: wastewater and sludge. The supernatant is directly discharged out of the system, and part of the remaining sludge is discharged out of the system through the sludge discharge port at the bottom of SBR reactor 1 to achieve biological phosphorus removal. The SRT is 17 days. The other part of the sludge, after being stirred, enters the top of the bypass anaerobic tank 3 through the bottom opening of SBR reactor 1 via peristaltic pump Ⅲ4.3. The bypass ratio is 20%. The bypass anaerobic tank 3 is filled with a biofilm carrier, specifically anaerobic biological carrier AMC, with a filling ratio of 25%.

[0061] Step 3: The returned sludge undergoes anaerobic fermentation and polyphosphate-accumulating bacteria screening in the bypass anaerobic tank 3, and then is returned to the first anaerobic section of the SBR reactor 1. The HRT of the bypass anaerobic tank is 96h, the dissolved oxygen concentration is less than 0.1mg / L, and the sludge concentration is 5700mg / L.

[0062] The final effluent indicators are: COD=19.5mg / L, TN=6.8mg / L, TP=0.5mg / L. All indicators meet the Class A discharge standard stipulated in the "Standard for Pollutant Discharge Indicators of Urban Wastewater Treatment Plants (GB18918-2002)".

[0063] Example 3

[0064] Step 1: Raw wastewater enters SBR reactor 1. The raw wastewater has a COD of 310 mg / L, TN of 33 mg / L, TP of 10 mg / L, a water temperature of 15℃, a hydraulic retention time (HRT) of 6h, a dissolved oxygen concentration of greater than 2.0 mg / L in the aerobic section, and a sludge concentration of 2800 mg / L.

[0065] Step 2: After the influent reaction of SBR reactor 1 is completed and sedimentation lasts for 30 minutes, the discharge is divided into two parts: wastewater and sludge. The supernatant is directly discharged out of the system, and part of the remaining sludge is discharged out of the system through the sludge discharge port at the bottom of SBR reactor 1 to achieve biological phosphorus removal. The SRT is 17 days. The other part of the sludge, after being stirred, enters the top of the bypass anaerobic tank 3 through the bottom opening of SBR reactor 1 via peristaltic pump Ⅲ4.3. The bypass ratio is 20%. The bypass anaerobic tank 3 is filled with a biofilm carrier, specifically anaerobic biological carrier AMC, with a filling ratio of 25%.

[0066] Step 3: The returned sludge undergoes anaerobic fermentation and polyphosphate-accumulating bacteria screening in the bypass anaerobic tank 3, and then is returned to the first anaerobic section of the SBR reactor 1. The HRT of the bypass anaerobic tank is 96h, the dissolved oxygen concentration is less than 0.1mg / L, and the sludge concentration is 5900mg / L.

[0067] The final effluent indicators are: COD=18.4mg / L, TN=6.2mg / L, TP=0.4mg / L. All indicators meet the Class A discharge standard stipulated in the "Standard for Pollutant Discharge Indicators of Urban Wastewater Treatment Plants (GB18918-2002)".

[0068] Example 4

[0069] Step 1: Raw wastewater enters SBR reactor 1. The raw wastewater has a COD of 275 mg / L, TN of 27 mg / L, TP of 7.8 mg / L, a water temperature of 19℃, a hydraulic retention time (HRT) of 6h, a dissolved oxygen concentration of greater than 2.0 mg / L in the aerobic section, and a sludge concentration of 2900 mg / L.

[0070] Step 2: After the influent reaction of SBR reactor 1 is completed and sedimentation lasts for 30 minutes, the discharge is divided into two parts: wastewater and sludge. The supernatant is directly discharged out of the system, and part of the remaining sludge is discharged out of the system through the sludge discharge port at the bottom of SBR reactor 1 to achieve biological phosphorus removal. The SRT is 17 days. The other part of the sludge, after being stirred, enters the top of the bypass anaerobic tank 3 through the bottom opening of SBR reactor 1 via peristaltic pump Ⅲ4.3. The bypass ratio is 20%. The bypass anaerobic tank 3 is filled with a biofilm carrier, specifically anaerobic biological carrier AMC, with a filling ratio of 25%.

[0071] Step 3: The returned sludge undergoes anaerobic fermentation and polyphosphate screening in the side-flow anaerobic tank 3, and then is returned to the first anaerobic section of the SBR reactor (1). The HRT of the side-flow anaerobic tank is 96h, the dissolved oxygen concentration is less than 0.1mg / L, and the sludge concentration is 5700mg / L.

[0072] The final effluent indicators are: COD=20.4mg / L, TN=6.5mg / L, TP=0.4mg / L. All indicators meet the Class A discharge standard stipulated in the "Standard for Pollutant Discharge Indicators of Urban Wastewater Treatment Plants (GB18918-2002)".

[0073] Example 5

[0074] Step 1: Raw wastewater enters SBR reactor 1. The raw wastewater has a COD of 330 mg / L, TN of 35 mg / L, TP of 11.2 mg / L, a water temperature of 19℃, a hydraulic retention time (HRT) of 6h, a dissolved oxygen concentration of greater than 2.0 mg / L in the aerobic section, and a sludge concentration of 2850 mg / L.

[0075] Step 2: After the influent reaction of SBR reactor 1 is completed and sedimentation lasts for 30 minutes, the discharge is divided into two parts: wastewater and sludge. The supernatant is directly discharged out of the system, and part of the remaining sludge is discharged out of the system through the sludge discharge port at the bottom of SBR reactor 1 to achieve biological phosphorus removal. The SRT is 17 days. The other part of the sludge, after being stirred, enters the top of the bypass anaerobic tank 3 through the bottom opening of SBR reactor 1 via peristaltic pump Ⅲ4.3. The bypass ratio is 20%. The bypass anaerobic tank 3 is filled with a biofilm carrier, specifically anaerobic biological carrier AMC, with a filling ratio of 25%.

[0076] Step 3: The returned sludge undergoes anaerobic fermentation and polyphosphate-accumulating bacteria screening in the side-flow anaerobic tank 3, and then is returned to the first anaerobic section of the SBR reactor 1. The HRT of the side-flow anaerobic tank is 96h, the dissolved oxygen concentration is less than 0.1mg / L, and the sludge concentration is 5600mg / L.

[0077] The final effluent indicators are: COD=18.7mg / L, TN=6.1mg / L, TP=0.4mg / L. All indicators meet the Class A discharge standard stipulated in the "Standard for Pollutant Discharge Indicators of Urban Wastewater Treatment Plants (GB18918-2002)".

[0078] Example 6

[0079] Step 1: Raw wastewater enters SBR reactor 1. The raw wastewater has a COD of 250 mg / L, TN of 35 mg / L, TP of 12 mg / L, a water temperature of 19℃, a hydraulic retention time (HRT) of 6h, a dissolved oxygen concentration of greater than 2.0 mg / L in the aerobic section, and a sludge concentration of 2700 mg / L.

[0080] Step 2: After the influent reaction of SBR reactor 1 is completed and sedimentation lasts for 30 minutes, the discharge is divided into two parts: wastewater and sludge. The supernatant is directly discharged out of the system, and part of the remaining sludge is discharged out of the system through the sludge discharge port at the bottom of SBR reactor 1 to achieve biological phosphorus removal. The SRT is 17 days. The other part of the sludge, after being stirred, enters the top of the bypass anaerobic tank 3 through the bottom opening of SBR reactor 1 via peristaltic pump Ⅲ4.3. The bypass ratio is 20%. The bypass anaerobic tank 3 is filled with a biofilm carrier, specifically anaerobic biological carrier AMC, with a filling ratio of 25%.

[0081] Step 3: The returned sludge undergoes anaerobic fermentation and polyphosphate-accumulating bacteria screening in the bypass anaerobic tank 3, and then is returned to the first anaerobic section of the SBR reactor 1. The HRT of the bypass anaerobic tank is 96h, the dissolved oxygen concentration is less than 0.1mg / L, and the sludge concentration is 5900mg / L.

[0082] The final effluent indicators are: COD=33.7mg / L, TN=8.7mg / L, TP=0.4mg / L. All indicators meet the Class A discharge standard stipulated in the "Standard for Pollutant Discharge Indicators of Urban Wastewater Treatment Plants (GB18918-2002)".

[0083] The TP removal effects of Examples 1-6 are as follows: Figure 2 As shown, the COD removal effect is as follows: Figure 3 As shown, the TN removal effect is as follows: Figure 4 As shown in the figure, the present invention achieves a TP removal rate of over 90%, a TN removal rate of over 70%, and an effluent COD of over 80% for wastewater.

Claims

1. A process for enhanced nitrogen and phosphorus removal by using side-flow sludge membrane composite to enhance the utilization of internal carbon source, characterized in that, The phosphorus removal device comprises an SBR reactor (1), the bottom of the SBR reactor (1) is connected with the top of a bypass anaerobic tank (3) through a peristaltic pump III (4-3), the bottom of the bypass anaerobic tank (3) is connected with the top of the SBR reactor (1) through a peristaltic pump II (4-2), the top and the bottom of the SBR reactor (1) are respectively connected with a peristaltic pump I (4-1) and a peristaltic pump IV (4-4) as water inlet and outlet pumps, and the SBR reactor (1), the bypass anaerobic tank (3), the peristaltic pump I (4-1), the peristaltic pump II (4-2), the peristaltic pump III (4-3) and the peristaltic pump IV (4-4) are connected with a controller (2). The method is implemented according to the following steps: Step 1: the raw sewage is pumped into the SBR reactor through the peristaltic pump I and stays for 6 hours at 15-30 DEG C; Step 2: the supernatant after precipitation in step 1 is directly discharged out of the system through the peristaltic pump IV (4-4), part of the residual sludge is discharged out of the system through the sludge discharge port at the bottom of the SBR reactor (1), and another part of the sludge is taken as the reflux sludge and introduced into the top of the bypass anaerobic tank (3) through the peristaltic pump III (4-3) after being stirred evenly; Step 3: the reflux sludge in step 2 is subjected to anaerobic fermentation and phosphorus accumulating bacteria screening in the bypass anaerobic tank (3) and then is refluxed into the SBR reactor (1) through the peristaltic pump II (4-2); Step 4: the raw sewage is introduced into the SBR reactor (1), and steps 2 and 3 are repeated to biologically remove phosphorus from the raw sewage; The SBR reactor (1) adopts a multi-stage A / O operation mode with segmented water inlet; The segmented water inlet of the SBR reactor (1) is specifically divided into a first anaerobic section and a second anaerobic section, the water inlet of the first anaerobic section is 1 / 2 of the total amount, the anaerobic time is 60 min, the aerobic time is 90 min, the water inlet of the second anaerobic section is 1 / 2 of the total amount, the anaerobic time is 60 min, the aerobic time is 90 min, the sedimentation time is 30 min, the drainage time is 25 min, and the stirring state is water inlet into the bypass anaerobic tank (3) for 5 min.

2. The process for enhanced removal of nitrogen and phosphorus by utilizing the side-flow mud membrane composite enhanced internal carbon source according to claim 1, characterized in that, The SBR reactor (1) is internally provided with a stirrer.

3. The process for enhanced removal of nitrogen and phosphorus by utilizing the lateral flow mud film composite enhanced internal carbon source according to claim 1, characterized in that, The bypass anaerobic tank (3) is internally provided with a stirrer.

4. The process for enhanced removal of nitrogen and phosphorus by utilizing the lateral flow mud film composite enhanced internal carbon source according to claim 1, characterized in that, The residence time of the sludge in the system is 17 days.

5. The process for enhanced removal of nitrogen and phosphorus by utilizing the lateral flow mud film composite enhanced internal carbon source according to claim 1, characterized in that, The bypass ratio of the sludge into the bypass anaerobic tank (3) in step 2 is 20%.

6. The process for enhanced removal of nitrogen and phosphorus by utilizing the lateral flow mud film composite enhanced internal carbon source according to claim 1, characterized in that, The hydraulic residence time of the reflux sludge in the bypass anaerobic tank (3) in step 3 is 96 h, the dissolved oxygen concentration is 0.01-0.1 mg / L, and the sludge concentration is 5800 mg / L.

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