Synchronous nitrogen and phosphorus removal integrated system and method for low-carbon-nitrogen-ratio sewage based on MBBR (moving bed biofilm reactor) process

Abstract

The invention discloses an MBBR (Moving Bed Biofilm Reactor) process-based synchronous nitrogen and phosphorus removal integrated system and method for low-carbon-nitrogen-ratio sewage. Along with strict execution of an environmental protection supervision system, sewage treatment discharge standards of various regions are increasingly strict. The system is sequentially provided with the following areas: an anaerobic tank, a 1 # front anoxic tank, a 1 # rear anoxic tank, a 1 # aerobic tank, a 2 # anoxic tank, a 2 # aerobic tank, a 3 # anoxic tank, a 3 # aerobic tank, a secondary sedimentation tank, a flocculation tank, a denitrification deep-bed filter tank and a water outlet area, an aerator is arranged at the bottom of the aerobic tank; the anaerobic tank is connected with the 1 # rear anoxic tank through a mixed liquid return pipe, and a return pump is arranged on the mixed liquid return pipe; a sludge return pipe and a residual sludge discharge pipe are arranged at the bottom of the secondary sedimentation tank; the sludge return pipe is connected with the 1 # front anoxic tank; sewage inlet pipes are respectively arranged at the tops of the No.1 front anoxic tank, the No.2 anoxic tank and the No.3 anoxic tank. A water inlet carbon source is reasonably distributed in a segmented water inlet mode, and it is ensured that the effluent quality reaches the standard under the condition of the low C / N ratio.

Description

Technical Field

[0002] The present invention belongs to the technical field of sewage treatment, and particularly relates to an integrated system and method for synchronous nitrogen and phosphorus removal from low-carbon-nitrogen ratio sewage based on the MBBR process. Background Technique

[0003] With the rapid economic development and the acceleration of the urbanization process, the domestic water consumption and sewage discharge of residents have been continuously rising. However, restricted by the tight urban land and the ecological red line, the growth rate of the number of newly built sewage treatment plants has slowed down significantly. The numbers of newly built urban sewage treatment plants in the country from 2019 to 2022 were 2,471, 2,618, 2,827, and 2,894 respectively. The traditional activated sludge process faces the dual dilemmas of large floor area and limited volumetric load, and it is difficult to cope with the continuously increasing sewage treatment demand.

[0004] Organic pollutants, nitrogen, and phosphorus, with chemical oxygen demand as a representative index, are the main components of domestic sewage. Discharging them into natural water bodies without reaching the standards will cause serious harm to the natural ecology and human health. With the strict implementation of the environmental protection supervision system, the sewage treatment discharge standards in various places have become more stringent. Many cities have formulated local standards based on the first-class A standard of the "Discharge Standard of Pollutants for Municipal Sewage Treatment Plants" (GB18918-2002), requiring the main indicators to reach "quasi-Class IV and quasi-Class III of the surface water", etc.

[0005] Taking A 2 0 process as a representative, the traditional activated sludge process can synchronously meet the requirements of nitrogen and phosphorus removal. The main process flow is: influent - anaerobic tank - anoxic tank - aerobic tank - secondary sedimentation tank - effluent. The sludge in the secondary sedimentation tank is returned to the anaerobic tank, and the nitrified liquid in the aerobic tank is refluxed to the anoxic tank to provide NO3 - for denitrification. However, the following problems exist in the operation process: 1) The sludge in the secondary sedimentation tank is returned to the anaerobic tank, and the nitrate contained in the sludge will affect the anaerobic phosphorus release process of polyphosphate-accumulating organisms, hindering the anaerobic phosphorus release process; 2) The fierce competition for carbon sources between polyphosphate-accumulating organisms and denitrifying bacteria in the anaerobic section, combined with the fact that the influent water quality of sewage treatment plants in current cities, especially in southern China, generally shows the characteristics of a low C / N ratio, further increases the difficulty of biological nitrogen and phosphorus removal. How to achieve the discharge of total nitrogen up to the standard on the basis of not adding carbon sources and operating at high loads has become the main problem faced. Summary of the Invention

[0006] In order to make up for the deficiencies of the prior art, the present invention provides an integrated system and method for synchronous nitrogen and phosphorus removal from low carbon-nitrogen ratio sewage based on the MBBR process. The nitrate concentration in the mixed liquid refluxed to the anaerobic tank is relatively low, which avoids the influence of nitrate on the anaerobic phosphorus release process of polyphosphate-accumulating organisms and promotes the anaerobic phosphorus release process. By arranging the three sections of anoxic / aerobic alternately and adopting the method of segmented influent to reasonably distribute the influent carbon source, it ensures that the effluent quality meets the discharge standards under the condition of low C / N ratio.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows: An integrated system for synchronous nitrogen and phosphorus removal from low carbon-nitrogen ratio sewage based on the MBBR process is provided with the following areas arranged in sequence from front to back: Anaerobic tank A1, 1# front anoxic tank A2-1, 1# rear anoxic tank A2-2, 1# aerobic tank A3, 2# anoxic tank A4, 2# aerobic tank A5, 3# anoxic tank A6, 3# aerobic tank A7, secondary sedimentation tank A8, flocculation tank A9, denitrification deep bed filter A10 and effluent area A11; different areas are separated by partition walls, and communication ports are provided on the partition walls, and adjacent areas are kept connected through the communication ports; Aerobic tank tubular microporous aerators C1 are arranged at the bottoms of the 1# aerobic tank A3, 2# aerobic tank A5 and 3# aerobic tank A7; The bottom of the anaerobic tank A1 is connected to the bottom of the 1# rear anoxic tank A2-2 through a mixed liquid reflux pipe G7, and a mixed liquid reflux pump B2 is arranged on the mixed liquid reflux pipe G7; A sludge reflux pipe G8 and a surplus sludge discharge pipe G9 are arranged at the bottom of the secondary sedimentation tank A8. The sludge reflux pipe G8 is connected to the 1# front anoxic tank A2-1, and a sludge reflux pump B3 is arranged on the sludge reflux pipe G8; 1# front anoxic tank sewage inlet pipes G1, 2# anoxic tank sewage inlet pipes G2 and 3# anoxic tank sewage inlet pipes G3 are respectively arranged at the tops of the 1# front anoxic tank A2-1, 2# anoxic tank A4 and 3# anoxic tank A6. The 1# anoxic tank sewage inlet pipe G1, 2# anoxic tank sewage inlet pipe G2 and 3# anoxic tank sewage inlet pipe G3 are connected to a sewage inlet pump B1, and the wastewater to be treated is pumped in by the sewage inlet pump B1.

[0008] Furthermore, an anaerobic tank stirrer J2 is arranged at the bottom of the anaerobic tank A1, anoxic tank stirrers J1 are arranged at the bottoms of the 1# front anoxic tank A2-1, 1# rear anoxic tank A2-2, 2# anoxic tank A4 and 3# anoxic tank A6, and a flocculation tank rapid stirrer J3 is arranged at the bottom of the flocculation tank A9.

[0009] Furthermore, aerobic tank suspended fillers X1 are added into the 1# aerobic tank A3, 2# aerobic tank A5 and 3# aerobic tank A7.

[0010] Further, the aerobic tank tubular microporous aerators C1 at the bottoms of the 1# aerobic tank A3, 2# aerobic tank A5, and 3# aerobic tank A7 are respectively connected to the outlet end of the aerobic tank aeration blower F1 through the 1# aerobic tank aeration inlet pipe G4, 2# aerobic tank aeration inlet pipe G5, and 3# aerobic tank aeration inlet pipe G6.

[0011] Further, an aerobic tank tubular microporous aerator pipe clamp support E1 is arranged at the bottom of the aerobic tank tubular microporous aerator C1.

[0012] Further, a packing interception net is arranged at the communicating port of the pool walls of the 1# aerobic tank A3, 2# aerobic tank A5, and 3# aerobic tank A7.

[0013] Further, a flocculation tank dosing pipe G10 is arranged inside the flocculation tank A9.

[0014] Further, a denitrification filter dosing pipe G11 is arranged inside the denitrification deep bed filter A10, and a water distribution area, a denitrification filter quartz sand packing layer X2, a denitrification filter cobblestone support layer X3, and a denitrification filter filter plate and filter brick X4 are respectively arranged from top to bottom.

[0015] Further, a denitrification filter backwash inlet air pipe G12 and a denitrification filter backwash inlet water pipe G13 are arranged at the bottom of the denitrification deep bed filter A10; The denitrification filter backwash inlet air pipe G12 is connected to the denitrification filter air washing blower F2; The denitrification filter backwash inlet water pipe G13 is connected to the outlet end of the denitrification filter backwash inlet water pump B4, and the inlet end of the denitrification filter backwash inlet water pump B4 is connected to the outlet pipe G14 of the water outlet area A11.

[0016] An integrated method for synchronous nitrogen and phosphorus removal from low carbon-nitrogen ratio sewage based on the MBBR process is specifically as follows: The sewage mixture in the anaerobic tank A1 sequentially passes through the 1# pre-anoxic tank A2-1, 1# post-anoxic tank A2-2, 1# aerobic tank A3, 2# anoxic tank A4, 2# aerobic tank A5, 3# anoxic tank A6, 3# aerobic tank A7, secondary sedimentation tank A8, flocculation tank A9, and denitrification deep bed filter A10 for treatment, and is discharged through the water outlet area A11; First, the wastewater to be treated is pumped into the 1# anoxic tank A2-1, 2# anoxic tank A4, and 3# anoxic tank A6 respectively through the 1# anoxic tank sewage inlet pipe G1, 2# anoxic tank sewage inlet pipe G2, and 3# anoxic tank sewage inlet pipe G3 by the sewage inlet pump B1; Air is pressurized by the aerobic tank aeration blower F1 and enters each aerobic tank; the filled suspended packing X1 in the aerobic tank provides an attachment site for nitrifying bacteria; the nitrification liquid generated in each aerobic zone directly enters the next anoxic zone to carry out denitrification using the carbon source in the raw water; Part of the sludge sedimented at the bottom of the secondary sedimentation tank A8 is pressurized by the sludge return pump B3 and enters the 1# pre-anoxic tank A2-1 through the sludge return pipe G8; the excess surplus sludge is discharged out of the system through the surplus sludge discharge pipe G9; The mixed liquor in the sewage in the 1# post-anoxic tank A2-2 is pressurized by the mixed liquor return pump B2 and enters the anaerobic tank A1 through the mixed liquor return pipe G7; The mixed liquor in the sewage in the secondary sedimentation tank A8 enters the flocculation tank A9, and the coagulant and phosphorus removal agent are added into the flocculation tank A9 through the dosing pipe G10. After being mixed and stirred by the rapid stirrer J3, large particles are formed; The external carbon source is added into the denitrifying deep bed filter A10 through the dosing pipe G11. Through further denitrification and nitrogen removal, the total nitrogen in the sewage is removed; the suspended particles in the mixed liquor in the denitrifying deep bed filter A10 are intercepted in the pores between the quartz sand packing layers X2 of the denitrifying filter; The air is pressurized by the air washing blower F2 and enters the denitrifying deep bed filter A10. The backwashing inlet water pump B4 presses the water in the outlet area into the denitrifying deep bed filter A10 through the backwashing inlet pipe G13, and the denitrifying deep bed filter A10 is backwashed by the way of air-water combined backwashing; the water filtered by the denitrifying deep bed filter A10 finally flows out of the system through the outlet pipe G14.

[0017] The beneficial effects of the present invention: 1) In the present invention, the anoxic tank in the starting process is divided into the front and rear ends. A sludge return pipe is arranged between the 1# pre-anoxic tank and the secondary sedimentation tank, and a mixed liquor return pipe is arranged between the 1# post-anoxic tank and the anaerobic tank; after the returned sludge undergoes sufficient denitrification in the front and rear anoxic tanks, the nitrate contained in the returned sludge is effectively removed, so as to ensure that the nitrate concentration in the mixed liquor returned to the anaerobic tank is relatively low, largely avoiding the influence of nitrate on the anaerobic phosphorus release process of polyphosphate-accumulating bacteria and promoting the anaerobic phosphorus release process; 2) Through the three-stage alternating arrangement of anoxic / aerobic and the method of segmented water inlet, the present invention reasonably distributes the influent carbon source. The nitrified liquid generated in the aerobic zone in the system directly enters the next anoxic zone to carry out denitrification with the carbon source in the raw water, breaking through the carbon source limitation of the traditional process, realizing the full utilization of the raw water carbon source, and efficiently exerting the nitrogen and phosphorus removal effects of sewage with a low C / N ratio; at the same time, the nitrified liquid internal reflux facility in the traditional A 2 O process is omitted, saving the operation energy consumption; 3) By filling suspended packing in the aerobic zone, the present invention gives play to the biofilm enrichment effect of the packing, realizes the zonal enrichment and synergistic enhancement of functional bacteria groups (nitrifying / denitrifying bacteria, polyphosphate-accumulating bacteria) in a compact space, effectively alleviates the contradiction between the sludge ages of polyphosphate-accumulating bacteria and nitrifying bacteria, significantly improves the treatment efficiency per unit volume, and reduces the floor area; 4) A flocculation tank is arranged at the front end of the denitrifying deep bed filter of the present invention, effectively playing the roles of physically intercepting phosphorus removal and denitrifying nitrogen removal, ensuring that the effluent quality meets the discharge standards under the condition of low C / N ratio; 5) The present invention has strong adaptability to low C / N sewage, good removal effects on organic pollutants, nitrogen, phosphorus and suspended solids, high treatment efficiency per unit volume, high carbon source utilization rate, high degree of process integration, small floor area, up-to-standard effluent quality and strong guarantee. Brief Description of the Drawings

[0018] Figure 1 It is a structural schematic diagram of the nitrogen and phosphorus removal integrated system of the present invention; In the figure, A1 - anaerobic tank, A2-1 - 1# pre-anoxic tank, A2-2 - 1# post-anoxic tank, A3 - 1# aerobic tank, A4 - 2# anoxic tank, A5 - 2# aerobic tank, A6 - 3# anoxic tank, A7 - 3# aerobic tank, A8 - secondary sedimentation tank, A9 - flocculation tank, A10 - denitrifying deep bed filter, A11 - effluent area, G1 - sewage inlet pipe of 1# anoxic tank, G2 - sewage inlet pipe of 2# anoxic tank, G3 - sewage inlet pipe of 3# anoxic tank, G4 - aeration inlet pipe of 1# aerobic tank, G5 - aeration inlet pipe of 2# aerobic tank, G6 - aeration inlet pipe of 13# aerobic tank, G7 - mixed liquor return pipe, G8 - sludge return pipe, G9 - excess sludge discharge pipe, G10 - chemical dosing pipe of flocculation tank, G11 - chemical dosing pipe of denitrifying filter, G12 - backwashing air inlet pipe of denitrifying filter, G13 - backwashing water inlet pipe of denitrifying filter, G14 - outlet pipe, X1 - suspended packing in aerobic tank, X2 - quartz sand packing layer of denitrifying filter, X3 - cobblestone supporting layer of denitrifying filter, X4 - filter plate and filter brick of denitrifying filter, C1 - tubular microporous aerator in aerobic tank, E1 - pipe clamp support of tubular microporous aerator in aerobic tank, F1 - aeration blower in aerobic tank, F2 - air washing blower of denitrifying filter, B1 - sewage inlet pump, B2 - mixed liquor return pump, B3 - sludge return pump, B4 - backwashing water inlet pump of denitrifying filter, J1 - stirrer in anoxic tank, J2 - stirrer in anaerobic tank, J3 - rapid stirrer in flocculation tank. Detailed Embodiments

[0019] The present invention will be described in detail below in conjunction with the specific embodiments.

[0020] The present invention provides a synchronous nitrogen and phosphorus removal integrated system and method for low carbon-nitrogen ratio sewage based on the MBBR process. The nitrate concentration in the mixed liquor refluxed to the anaerobic tank is relatively low, avoiding the influence of nitrate on the anaerobic phosphorus release process of polyphosphate-accumulating bacteria and promoting the anaerobic phosphorus release process. By arranging three-stage alternation of anoxic / aerobic and adopting the method of segmented water inlet to reasonably distribute the influent carbon source, it is ensured that the effluent quality meets the discharge standards under the condition of low C / N ratio.

[0021] Such as Figure 1As shown in the figure, the integrated system for simultaneous nitrogen and phosphorus removal from low carbon-nitrogen ratio sewage based on the MBBR process of the present invention is specifically as follows: The following areas are arranged in sequence from front to back: anaerobic tank A1, 1# pre-anoxic tank A2-1, 1# post-anoxic tank A2-2, 1# aerobic tank A3, 2# anoxic tank A4, 2# aerobic tank A5, 3# anoxic tank A6, 3# aerobic tank A7, secondary sedimentation tank A8, flocculation tank A9, denitrifying deep bed filter A10 and effluent area A11; different areas are separated by partition walls, and communication ports are arranged on the partition walls, and adjacent areas are kept connected through the communication ports; an outlet pipe is arranged at the rear end of the effluent area A10, and the sewage treated by the integrated system is discharged from the outlet pipe.

[0022] 1# pre-anoxic tank A2-1, 2# anoxic tank A4, and 3# anoxic tank A6 are respectively provided with 1# anoxic tank sewage inlet pipe G1, 2# anoxic tank sewage inlet pipe G2, and 3# anoxic tank sewage inlet pipe G3 at the top. The 1# anoxic tank sewage inlet pipe G1, 2# anoxic tank sewage inlet pipe G2, and 3# anoxic tank sewage inlet pipe G3 are connected to the sewage inlet pump B1, and the wastewater to be treated is pumped into the system by the sewage inlet pump B1.

[0023] An anaerobic tank stirrer J2 is arranged at the bottom of the anaerobic tank A1, anoxic tank stirrers J1 are arranged at the bottoms of the 1# pre-anoxic tank A2-1, 1# post-anoxic tank A2-2, 2# anoxic tank A4, and 3# anoxic tank A6, and a flocculation tank rapid stirrer J3 is arranged at the bottom of the flocculation tank A9.

[0024] Aerobic tank tube microporous aerators C1 are arranged at the bottoms of the 1# aerobic tank A3, 2# aerobic tank A5, and 3# aerobic tank A7; the aerobic tank tube microporous aerators C1 at the bottoms of the 1# aerobic tank A3, 2# aerobic tank A5, and 3# aerobic tank A7 are respectively connected to the outlet ends of the 1# aerobic tank aeration inlet pipe G4, 2# aerobic tank aeration inlet pipe G5, and 3# aerobic tank aeration inlet pipe G6 of the aerobic tank aeration blower F1, and the blower is used to supply air into the aerobic tank. An aerobic tank tube microporous aerator pipe clamp bracket E1 is arranged at the bottom of the aerobic tank tube microporous aerator C1. Packing interception nets are arranged at the communication ports of the pool walls of the 1# aerobic tank A3, 2# aerobic tank A5, and 3# aerobic tank A7, and the interception nets are attached to the pool walls. Aerobic tank suspended packing X1 is added into the 1# aerobic tank A3, 2# aerobic tank A5, and 3# aerobic tank A7. The suspended packing is one of polypropylene packing, polyethylene packing, and polyurethane packing, and the filling volume of the suspended packing is 20-60% of the effective volume of the aerobic tank.

[0025] A sludge return pipe G8 and a surplus sludge discharge pipe G9 are arranged at the bottom of the secondary sedimentation tank A8. The sludge return pipe G8 is connected to the 1# pre-anoxic tank A2-1, and a sludge return pump B3 is arranged on the sludge return pipe G8; the bottom of the anaerobic tank A1 is connected to the bottom of the 1# post-anoxic tank A2-2 through a mixed liquor return pipe G7, and a mixed liquor return pump B2 is arranged on the mixed liquor return pipe G7.

[0026] Inside the flocculation tank A9, a flocculation tank chemical dosing pipe G10 is provided. Flocculants and coagulants are added through the chemical dosing pipe, and after rapid stirring and mixing by a stirrer, physical and chemical effects are exerted to achieve the removal of suspended solids and phosphorus.

[0027] Inside the denitrifying deep bed filter A10, a denitrifying filter chemical dosing pipe G11 is provided. A water distribution area, a quartz sand packing layer X2 of the denitrifying filter, a cobblestone supporting layer X3 of the denitrifying filter, and a filter plate and filter brick X4 of the denitrifying filter are arranged from top to bottom. At the bottom of the denitrifying deep bed filter A10, a denitrifying filter backwash air inlet pipe G12 and a denitrifying filter backwash water inlet pipe G13 are provided; the denitrifying filter backwash air inlet pipe G12 is connected to the air washing blower F2 of the denitrifying filter; the blower provides a backwash air source for the filter; the denitrifying filter backwash water inlet pipe G13 is connected to the outlet end of the denitrifying filter backwash water pump B4, and the inlet end of the denitrifying filter backwash water pump B4 is connected to the outlet pipe G14 of the water outlet area A11; the treated water is used as the backwash water source, and the filter adopts the method of combined air-water backwashing.

[0028] The present invention also provides an integrated method for synchronous nitrogen and phosphorus removal from low carbon-nitrogen ratio sewage based on the MBBR process, specifically as follows: The sewage mixture in the anaerobic tank A1 sequentially passes through the 1# pre-anoxic tank A2-1, 1# post-anoxic tank A2-2, 1# aerobic tank A3, 2# anoxic tank A4, 2# aerobic tank A5, 3# anoxic tank A6, 3# aerobic tank A7, secondary sedimentation tank A8, flocculation tank A9, and denitrifying deep bed filter A10 for treatment, and is discharged through the water outlet area A11; First, the wastewater to be treated is pumped into the 1# anoxic tank sewage inlet pipe G1, 2# anoxic tank sewage inlet pipe G2, and 3# anoxic tank sewage inlet pipe G3 by the sewage inlet pump B1, and enters the 1# pre-anoxic tank A2-1, 2# anoxic tank A4, and 3# anoxic tank A6 respectively to achieve segmented water inlet; Air is pressurized by the aerobic tank aeration blower F1 and enters each aerobic tank to ensure an aerobic environment in the tank; the filled suspended packing X1 in the aerobic tank provides an attachment site for nitrifying bacteria, realizes the regional enrichment and synergistic enhancement of functional flora (nitrifying / denitrifying bacteria, phosphorus-accumulating bacteria), improves the volume utilization rate of the reaction tank, and at the same time omits the nitrification liquid internal reflux facility in the traditional A 2 O process, saving operating energy consumption; the nitrification liquid generated in each aerobic zone directly enters the next anoxic zone, and the carbon source in the raw water is used for denitrification, breaking through the carbon source limitation of the traditional process, realizing the full utilization of the raw water carbon source, and efficiently exerting the nitrogen and phosphorus removal effect of low C / N ratio sewage; Part of the sludge sedimented at the bottom of the secondary sedimentation tank A8 is pressurized by the sludge return pump B3 and enters the 1# pre-anoxic tank A2-1 through the sludge return pipe G8 to ensure the stability of the amount of activated sludge in the system; the excess surplus sludge is discharged out of the system through the surplus sludge discharge pipe G9, and the phosphorus released by the activated sludge microorganisms in the aerobic tank is also discharged synchronously; The sewage mixture in the 1# post-anoxic tank A2-2 is pressurized by the mixed liquor return pump B2 and enters the anaerobic tank A1 through the mixed liquor return pipe G7; after the denitrification in the 1# pre- and post-anoxic tanks, the nitrate contained in the returned sludge is effectively removed, thus ensuring a low nitrate concentration in the mixed liquor returned to the anaerobic tank; the low nitrate concentration in the mixed liquor effectively avoids the influence of nitrate on the anaerobic phosphorus release of polyphosphate-accumulating bacteria, alleviates the competition for carbon sources between denitrifying bacteria and anaerobic bacteria, promotes the anaerobic phosphorus release, and the mixed liquor in the 1# post-anoxic tank is less disturbed by the returned sludge, reducing the impact of the mixed liquor on the anaerobic tank environment and further ensuring a good nitrogen and phosphorus removal effect of the treatment process; The sewage mixture in the secondary sedimentation tank A8 enters the flocculation tank A9, and the coagulant and phosphorus removal agent are added to the flocculation tank A9 through the chemical dosing pipe G10. After being mixed and stirred by the rapid stirrer J3, large particles are formed and removed by filtration in the next denitrifying deep bed filter, effectively reducing the suspended solids and total phosphorus concentration in the water; The external carbon source is added to the denitrifying deep bed filter A10 through the chemical dosing pipe G11. Through further denitrification and nitrogen removal, the total nitrogen in the sewage is removed to meet the standard or better treatment standards for discharge; the suspended particles in the sewage mixture in the denitrifying deep bed filter A10 are intercepted in the pores between the quartz sand packing layers X2 of the denitrifying filter; The air washing blower F2 pressurizes the air and enters the denitrifying deep bed filter A10. The backwashing inlet water pump B4 presses the water in the outlet area into the denitrifying deep bed filter A10 through the backwashing inlet pipe G13, and the denitrifying deep bed filter A10 is backwashed by the combined air-water backwashing method; microorganisms grow on the filter material layer and form a biofilm. As the operation time goes by, the pores between the filter materials gradually decrease, and the thickness of the biofilm gradually increases, causing the water level in the water distribution area to rise and the filtration water quality to deteriorate. Therefore, backwashing is required; under the washing of air and water, friction occurs between the filter materials, and the solid suspended substances intercepted in the filter bed and the attached biofilm are removed, and the filtration capacity of the filter bed is restored. The water filtered by the denitrifying deep bed filter A10 finally flows out of the system through the outlet pipe G14.

[0029] In the description of the present invention, unless otherwise clearly defined and limited, the terms "arranged", "installed", "connected", "joined", "fixed" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] The content of the present invention is not limited to the examples listed. Any equivalent transformation of the technical solution of the present invention by those of ordinary skill in the art through reading the specification of the present invention is covered by the claims of the present invention.

Claims

1. An integrated system for synchronous nitrogen and phosphorus removal from low carbon-nitrogen ratio sewage based on the MBBR process, characterized in that: The following areas are arranged in sequence from front to back: Anaerobic tank A1, 1# front anoxic tank A2-1, 1# rear anoxic tank A2-2, 1# aerobic tank A3, 2# anoxic tank A4, 2# aerobic tank A5, 3# anoxic tank A6, 3# aerobic tank A7, secondary sedimentation tank A8, flocculation tank A9, denitrification deep bed filter A10 and effluent area A11; Different areas are separated by partition walls, and communication ports are arranged on the partition walls, and adjacent areas are kept connected through the communication ports; Aerobic tank tubular microporous aerators C1 are arranged at the bottoms of the 1# aerobic tank A3, 2# aerobic tank A5 and 3# aerobic tank A7; The bottom of the anaerobic tank A1 is connected to the bottom of the 1# rear anoxic tank A2-2 through a mixed liquor return pipe G7, and a mixed liquor return pump B2 is arranged on the mixed liquor return pipe G7; A sludge return pipe G8 and a surplus sludge discharge pipe G9 are arranged at the bottom of the secondary sedimentation tank A8, the sludge return pipe G8 is connected to the 1# front anoxic tank A2-1, and a sludge return pump B3 is arranged on the sludge return pipe G8; 1# front anoxic tank sewage inlet pipes G1, 2# anoxic tank sewage inlet pipes G2, and 3# anoxic tank sewage inlet pipes G3 are respectively arranged at the tops of the 1# front anoxic tank A2-1, 2# anoxic tank A4, and 3# anoxic tank A6. The 1# anoxic tank sewage inlet pipe G1, 2# anoxic tank sewage inlet pipe G2, and 3# anoxic tank sewage inlet pipe G3 are connected to the sewage inlet pump B1, and the wastewater to be treated is pumped by the sewage inlet pump B1.

2. An integrated system for synchronous nitrogen and phosphorus removal from wastewater with a low carbon-nitrogen ratio based on the MBBR process according to claim 1, characterized in that: An anaerobic tank stirrer J2 is arranged at the bottom of the anaerobic tank A1, anoxic tank stirrers J1 are arranged at the bottoms of the 1# front anoxic tank A2-1, 1# rear anoxic tank A2-2, 2# anoxic tank A4 and 3# anoxic tank A6, and a flocculation tank rapid stirrer J3 is arranged at the bottom of the flocculation tank A9.

3. An integrated system for synchronous nitrogen and phosphorus removal from wastewater with a low carbon-nitrogen ratio based on the MBBR process according to claim 2, characterized in that: Aerobic tank suspended fillers X1 are added into the 1# aerobic tank A3, 2# aerobic tank A5 and 3# aerobic tank A7.

4. An integrated system for synchronous nitrogen and phosphorus removal from wastewater with a low carbon-nitrogen ratio based on the MBBR process according to claim 3, characterized in that: The aerobic tank tubular microporous aerators C1 at the bottoms of the 1# aerobic tank A3, 2# aerobic tank A5 and 3# aerobic tank A7 are respectively connected to the outlet end of the aerobic tank aeration blower F1 through the 1# aerobic tank aeration inlet pipe G4, 2# aerobic tank aeration inlet pipe G5, and 3# aerobic tank aeration inlet pipe G6.

5. An integrated system for simultaneous nitrogen and phosphorus removal from low carbon-nitrogen ratio sewage based on the MBBR process according to claim 4, characterized in that: An aerobic tank tubular microporous aerator pipe clamp bracket E1 is arranged at the bottom of the aerobic tank tubular microporous aerator C1.

6. An integrated system for synchronous nitrogen and phosphorus removal from low carbon-nitrogen ratio sewage based on the MBBR process according to claim 5, characterized in that: Packing interception nets are arranged at the communication ports of the pool walls of the 1# aerobic tank A3, 2# aerobic tank A5 and 3# aerobic tank A7.

7. An integrated system for simultaneous nitrogen and phosphorus removal from low carbon-nitrogen ratio sewage based on the MBBR process according to claim 6, characterized in that: A flocculation tank chemical dosing pipe G10 is arranged inside the flocculation tank A9.

8. An integrated system for synchronous nitrogen and phosphorus removal from wastewater with a low carbon-nitrogen ratio based on the MBBR process according to claim 7, characterized in that: A denitrification filter chemical dosing pipe G11 is arranged inside the denitrification deep bed filter A10, and a water distribution area, a denitrification filter quartz sand packing layer X2, a denitrification filter cobblestone support layer X3, and a denitrification filter plate and filter brick X4 are arranged from top to bottom.

9. An integrated system for simultaneous nitrogen and phosphorus removal from wastewater with a low carbon-nitrogen ratio based on the MBBR process according to claim 8, characterized in that: A denitrification filter backwashing inlet air pipe G12 and a denitrification filter backwashing inlet water pipe G13 are arranged at the bottom of the denitrification deep bed filter A10; The denitrification filter backwashing inlet air pipe G12 is connected to the denitrification filter air washing blower F2; The backwash inlet pipe G13 of the denitrification filter is connected to the outlet end of the backwash inlet pump B4 of the denitrification filter, and the inlet end of the backwash inlet pump B4 of the denitrification filter is connected to the outlet pipe G14 of the outlet area A11.

10. An integrated method for synchronous nitrogen and phosphorus removal from low carbon-nitrogen ratio sewage based on the MBBR process, characterized in that: The sewage mixture in the anaerobic tank A1 sequentially passes through the 1# pre-anoxic tank A2-1, 1# post-anoxic tank A2-2, 1# aerobic tank A3, 2# anoxic tank A4, 2# aerobic tank A5, 3# anoxic tank A6, 3# aerobic tank A7, secondary sedimentation tank A8, flocculation tank A9, and denitrification deep bed filter A10, and is discharged through the outlet area A11. First, the wastewater to be treated is pumped into the 1# anoxic tank by the sewage inlet pump B1, and enters the 1# pre-anoxic tank A2-1, 2# anoxic tank A4, and 3# anoxic tank A6 through the 1# anoxic tank sewage inlet pipe G1, 2# anoxic tank sewage inlet pipe G2, and 3# anoxic tank sewage inlet pipe G3 respectively. Air is pressurized by the aerobic tank aeration blower F1 and enters each aerobic tank; the packed suspended filler X1 in the aerobic tank provides an attachment site for nitrifying bacteria; the nitrified liquid generated in each aerobic zone directly enters the next anoxic zone for denitrification using the carbon source in the raw water. Part of the sludge settled at the bottom of the secondary sedimentation tank A8 is pressurized by the sludge return pump B3 and enters the 1# pre-anoxic tank A2-1 through the sludge return pipe G8; the excess surplus sludge is discharged out of the system through the surplus sludge discharge pipe G9. The sewage mixture in the 1# post-anoxic tank A2-2 is pressurized by the mixed liquid return pump B2 and enters the anaerobic tank A1 through the mixed liquid return pipe G7. The sewage mixture in the secondary sedimentation tank A8 enters the flocculation tank A9, and the coagulant and phosphorus removal agent are added to the flocculation tank A9 through the dosing pipe G10, and large particles are formed after mixing and stirring by the rapid stirrer J3. The external carbon source is added to the denitrification deep bed filter A10 through the dosing pipe G11, and the total nitrogen in the sewage is removed through further denitrification. The suspended particles in the sewage mixture in the denitrification deep bed filter A10 are intercepted in the pores between the quartz sand filler layers X2 of the denitrification filter. The air is pressurized by the air washing blower F2 and enters the denitrification deep bed filter A10, and the backwash inlet pump B4 presses the water from the outlet area into the denitrification deep bed filter A10 through the backwash inlet pipe G13, and the denitrification deep bed filter A10 is backwashed by the air-water combined backwashing method. The water filtered by the denitrification deep bed filter A10 finally exits the system through the outlet pipe G14.

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