Sewage denitrification assembly based on combination of MABR and flora colonization gel membrane filaments

Abstract

The invention discloses a sewage denitrification component based on compounding of MABR (Membrane Aerated Baffled Reactor) and flora colonization gel membrane filaments. According to the component, oxygen-permeable MABR membrane filaments and flora ecological colonization gel membrane filaments are packaged in a shell. Aerobic bacteria are enriched on the surface of the oxygen-permeable MABR membrane filaments by utilizing the oxygen-permeable characteristic of the oxygen-permeable MABR membrane filaments, so that short-cut nitrification from ammonia nitrogen to nitrite is realized; mutually-communicated micron-sized porous structures are arranged in the flora ecological planting gel membrane filaments, anaerobic ammonium oxidation bacteria can be loaded and protected in a high-density mode, the gel material wraps and slowly releases premixed nutrients, and flora activity is maintained. Through the spatial adjacent arrangement of the two membrane filaments, efficient coupling of short-cut nitrification and anaerobic ammonium oxidation is realized, and anaerobic ammonium oxidation bacteria directly utilize generated nitrite and residual ammonia nitrogen to generate nitrogen, so that efficient denitrification is completed in a single component. The design effectively solves the problems that anaerobic ammonium oxidation bacteria are difficult to enrich and are easily inhibited by dissolved oxygen, and has the advantages of high denitrification efficiency, low energy consumption, quick start, stable operation and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sewage treatment and specifically relates to a sewage denitrification assembly based on MABR and bacterial population colonization gel membrane wire combination. BACKGROUND

[0002] With the increasingly stringent requirements for environmental protection, sewage denitrification has become an important link in the field of water treatment. Traditional biological denitrification technology mainly relies on the "nitrification-denitrification" process. The nitrification process converts ammonia nitrogen (NH4 + ) into nitrite (NO2 - ) and nitrate (NO3 - ) under aerobic conditions, and the denitrification process reduces nitrate (NO3 - ) to nitrogen (N2) under anoxic conditions. This traditional path has obvious drawbacks: first, the nitrification process requires a large amount of aeration, resulting in high energy consumption; second, the denitrification process requires additional organic carbon sources as electron donors, resulting in high operating costs and potential secondary pollution; and finally, the entire process is long and produces a large amount of sludge.

[0003] The emergence of anaerobic ammonium oxidation (Anammox) technology provides a revolutionary new path for sewage denitrification. This technology can directly convert ammonia nitrogen (NH4 + ) to nitrogen (N2) using nitrite (NO2 - ) as an electron acceptor under anaerobic conditions. This process does not require oxygen and organic carbon sources, which can significantly reduce energy consumption and operating costs, and has a low sludge yield. However, anaerobic ammonium oxidation bacteria grow very slowly, have a long doubling time, and are very sensitive to environmental conditions (such as dissolved oxygen and temperature), especially dissolved oxygen, which can severely inhibit their activity. Therefore, how to efficiently enrich and stably retain high-activity anaerobic ammonium oxidation bacteria in actual engineering has become a bottleneck for the popularization and application of this technology.

[0004] Membrane aerated biofilm reactor (MABR) is a new type of sewage treatment technology. It uses oxygen-permeable membrane wires as biofilm attachment substrates, and oxygen diffuses through the membrane wall to form an aerobic biofilm on the surface of the membrane wire, mainly for nitrification. MABR technology has the advantages of high oxygen transfer efficiency and low energy consumption. However, traditional MABR technology is single-functioned, mainly focusing on the nitrification process, and is difficult to independently complete the full denitrification. If MABR is combined with anaerobic ammonium oxidation, a partitioned reactor system is usually required, which is complex and occupies a large area.

[0005] Currently, there are studies trying to couple nitrification and anaerobic ammonia oxidation process. But the existing coupling methods are mostly limited to mixing the two bacterial populations in the same sludge system or simple partitioned reactor, which has the problem of spatial niche overlap and functional inhibition of bacterial populations. Aerobic nitrifying bacteria consume oxygen and produce nitrite, while anaerobic ammonia oxidation bacteria need a strict anaerobic environment to utilize nitrite, and the two have completely opposite requirements for dissolved oxygen. In traditional systems, the diffusion of dissolved oxygen easily destroys the microenvironment of anaerobic ammonia oxidation bacteria, leading to a decrease in activity or even death. In addition, the lack of a dedicated carrier that can actively and continuously provide a micro-nutrient environment for slow-growing anaerobic ammonia oxidation bacteria leads to the loss of bacterial populations, slow system startup, and unstable operation.

[0006] Therefore, there is an urgent need in the art for a new integrated device that can achieve spatial coupling of nitrification and anaerobic ammonia oxidation bacterial populations, but effectively separate them in the microenvironment, both efficient mass transfer and provide a protected exclusive colonization space and nutrient support for anaerobic ammonia oxidation bacteria. SUMMARY

[0007] In view of the deficiencies of the prior art, the technical problem to be solved by the present application is to provide a wastewater denitrification assembly based on MABR and bacterial population colonization gel membrane filaments. This method solves the problem of spatial niche overlap and functional inhibition of bacterial populations by combining MABR membrane filaments with bacterial population colonization gel membrane filaments.

[0008] The application adopts the following technical solutions: A wastewater denitrification assembly based on MABR and bacterial population colonization gel membrane filaments, characterized in that it comprises: a component housing (1), the housing (1) is provided with an air inlet (2) and an air outlet (3); oxygen-permeable MABR membrane filaments (4) are packaged in the housing (1) to provide oxygen for aerobic bacteria attached to the surface and perform nitrification; bacterial population ecological colonization gel membrane filaments (5) are packaged in the housing (1), which load anaerobic ammonia oxidation bacteria inside and on the surface, and use the nitrite produced by the MABR membrane filaments (4) to perform anaerobic ammonia oxidation reaction with the remaining ammonia nitrogen in the wastewater, directly generating nitrogen, thereby realizing an efficient and short-range denitrification process.

[0009] The bacterial population ecological colonization gel membrane filaments (5) have a micrometer-scale porous structure that is interconnected inside, with an average pore size of 10-100 micrometers.

[0010] The bacterial population ecological colonization gel membrane filaments (5) can coat nutrients and serve as a carrier to supply nutrients to the loaded anaerobic ammonia oxidation bacteria in a slow-release manner.

[0011] The porous structure of the bacterial population ecological colonization gel membrane filaments (5) is formed by freeze-drying, phase separation, or chemical foaming process.

[0012] The gel material of the ecological colonization gel membrane filament (5) is a biocompatible gel, including one or more combinations of sodium alginate, polyacrylamide, agarose, polyvinyl alcohol or gelatin.

[0013] The preparation method of the ecological colonization gel membrane filament of the assembly is characterized in that it comprises the following steps: a. Mix the biocompatible gel precursor solution, the nutrient, and the pore-forming agent; b. Apply the mixed solution to the braided tube / fiber; c. Remove the pore-forming agent and fix the gel by freeze-drying or solvent displacement process, thereby forming a micron-scale porous structure inside the gel membrane filament.

[0014] The beneficial effects of the above technical solutions of the present application are as follows: By tightly integrating the oxygen-permeable MABR membrane filament and the ecological colonization gel membrane filament in space, the present application simultaneously completes the two biochemical processes of "short-term nitrification" and "anaerobic ammonia oxidation" in one reaction unit. The MABR membrane filament is responsible for efficiently converting ammonia nitrogen into nitrite, while the adjacent gel membrane filament immediately uses this nitrite and the remaining ammonia nitrogen to generate nitrogen gas. This successfully bypasses the full nitrification (to nitrate) and the step requiring organic carbon source in the traditional nitrification-denitrification path, shortening the denitrification process by up to 40%, and significantly improving the reaction rate and total nitrogen removal efficiency.

[0015] The present application ingeniously utilizes the oxygen supply characteristics of the MABR membrane filament from inside to outside, naturally forming an aerobic nitrification zone on its surface; while the ecological colonization gel membrane filament itself has a dense gel matrix and porous structure, which can effectively block the invasion of external dissolved oxygen, creating a protected exclusive anaerobic microenvironment for the anaerobic ammonia oxidation bacteria loaded inside. This "spatial coupling but microenvironment separation" design fundamentally solves the industry problem of coexistence and synergistic effect of aerobic and anaerobic bacteria, realizing the functional complementation and efficient cooperation of the microbial community. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 Wastewater denitrification assembly composed of MABR and microbial colonization gel membrane filament Figure 2 Microscopic diagram of MABR and microbial colonization gel membrane filament Figure 3 Ammonia nitrogen removal rate and total nitrogen removal rate of Example 1 and Control Example 1 DETAILED DESCRIPTION The technical solutions of the present application will be clearly and completely described below with examples. Obviously, the described examples are part of the examples of the present application, rather than all the examples. Based on the examples in the present application, all other examples obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0017] Example 1: Verification of the synergistic denitrification performance of the core assembly This example constructed the core assembly of the present application: 100 MABR membrane filaments and 100 sodium alginate-based microbial community ecological colonization gel membrane filaments (average pore size 50 μm) were packaged in parallel in the shell, which was used to treat simulated municipal wastewater with an ammonia nitrogen concentration of 100 mg / L. After stable operation at a hydraulic retention time (HRT) of 6 hours, the ammonia nitrogen removal rate of the system was continuously 93%, and the total nitrogen removal rate was stably above 85%, successfully realizing efficient in-situ coupling of short-cut nitrification and anaerobic ammonia oxidation.

[0018] Comparative Example 1 This comparative example used exactly the same conditions as Example 1, but only 200 MABR membrane filaments were packaged in the assembly without containing microbial community ecological colonization gel membrane filaments. The operation results showed that although the system could effectively perform nitrification (ammonia nitrogen removal rate 87%), the total nitrogen removal rate was low (65%), proving that the lack of anaerobic ammonia oxidation unit cannot complete deep denitrification, highlighting the necessity of the dual-membrane filament synergistic structure of the present application.

[0019] Example 2: Verification of the stability maintenance effect of nutrient slow-release of gel membrane filaments This example premixed ammonium salt and nitrite as built-in slow-release nutrients during the preparation of the microbial community ecological colonization gel membrane filaments on the basis of Example 1. The results showed that the assembly successfully started and achieved 95% ammonia nitrogen removal rate and 88% total nitrogen removal rate within 3 days, showing excellent denitrification performance and start-up speed.

[0020] Comparative Example 2 This comparative example used sodium alginate gel membrane filaments without any built-in nutrients, only with physical porous structure (the rest was consistent with Example 2), the start-up of the control system was delayed, and it took 8 days to complete the biofilm formation, and the stable ammonia nitrogen and total nitrogen removal rates were only 92% and 83%, respectively. This result clearly shows that the lack of built-in nutrient slow-release will lead to slow colonization and insufficient activity of anaerobic ammonia oxidation bacteria, thereby restricting the denitrification performance and start-up speed of the system.

[0021] Example 3: Verification of the promotion effect of porous structure on microbial colonization and system start-up The present embodiment prepares a microbial community ecological colonization gel membrane filament with an average pore size of 30-70 μm (the preferred range of the present application) and assembles it into an assembly with a MABR membrane filament. During the start-up period of treating simulated sewage, after the assembly is stably operated, the ammonia nitrogen removal rate reaches 95%, the total nitrogen removal rate is 83%, and microscopic observation confirms that the anaerobic ammonia oxidation bacteria achieve high-density and uniform colonization in the internal pores of the gel, the system starts quickly and operates stably.

[0022] Comparative Example 3 The present comparative example uses a dense solid gel membrane filament of the same material but without a clear porous structure. Under the same start-up conditions, after stable operation, the ammonia nitrogen removal rate is 85%, and the total nitrogen removal rate is 70%. Microscope observation shows that the anaerobic ammonia oxidation bacteria can only sporadically adhere to the surface of the membrane filament and cannot effectively load and proliferate inside, making it difficult to start the system, fully demonstrating that the "interpenetrating porous structure" is an indispensable technical feature to achieve high-density colonization of the microbial community.

Claims

1. A wastewater denitrification module based on MABR and microbial colonization gel membrane filaments, characterized in that, include: A component housing (1) is provided with an air inlet (2) and an air outlet (3); an oxygen-permeable MABR membrane fiber (4) is encapsulated in the housing (1) and is used to provide oxygen to the aerobic bacteria attached to its surface and carry out nitrification; a microbial community ecological colonization gel membrane fiber (5) is encapsulated in the housing (1), and its interior and surface are loaded with anaerobic ammonia-oxidizing bacteria. The nitrite generated by the MABR membrane fiber (4) is used to carry out anaerobic ammonia oxidation reaction with the remaining ammonia nitrogen in the sewage to directly generate nitrogen gas, thereby achieving a high-efficiency and short-range denitrification process.

2. The wastewater denitrification component according to claim 1, characterized in that, The microbial colonization gel membrane filaments (5) have interconnected micron-sized porous structures with an average pore size of 10-100 micrometers. The microbial colonization gel membrane filaments (5) can encapsulate nutrients and act as a carrier to supply nutrients to the loaded anaerobic ammonia-oxidizing bacteria in a slow-release manner.

3. The porous structure of the microbial community ecological colonization gel membrane filament (5) according to claim 2 is formed by freeze drying, phase separation or chemical foaming process.

4. The gel material of the microbial community ecological colonization gel membrane filament (5) according to claim 2 is a biocompatible gel, including one or more of sodium alginate, polyacrylamide, agarose, polyvinyl alcohol or gelatin.

5. A method for preparing microbial colonization gel membrane filaments for any of the components described in claims 1-4, characterized in that, Includes the following steps: a. Mix the biocompatible gel precursor solution, nutrients, and pore-forming agent; b. Apply the mixture to the braided tubing / fiber; c. The pore-forming agent is removed and the gel is fixed by freeze-drying or solvent displacement process, thereby forming an interconnected micron-sized porous structure inside the gel membrane filaments.

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