Biological adsorption-partial nitrification-anaerobic ammonium oxidation process based on functional carrier

Abstract

The present invention belongs to the technical field of sewage treatment. Disclosed is a biological adsorption-partial nitrification-anaerobic ammonium oxidation process based on a functional carrier. The process of the present invention is mainly composed of a biological adsorption section, a partial nitrification section, and an anaerobic ammonium oxidation section, wherein in the biological adsorption section, microorganisms in a logarithmic growth phase are screened and enriched by means of a short hydraulic retention time, and organic matters can be efficiently adsorbed; in the partial nitrification section, a nitrification functional carrier is added to enhance the adsorption of ammonia nitrogen, so as to enrich ammonium oxidation bacteria, and a relatively low level of dissolved oxygen is controlled, so that stable partial nitrification is achieved; and in the anaerobic ammonium oxidation section, an anaerobic ammonium oxidation functional carrier is added, so that the biomass and activity of anaerobic ammonium oxidation bacteria are improved by means of enrichment, and the autotrophic nitrogen removal efficiency is improved. The present invention does not need an additional carbon source, has a small aeration amount and low operating costs, and has great prospects in engineering applications.

Description

A biosorption-partial nitrification-anaerobic ammonium oxidation process based on functional carriers Technical Field

[0001] The present invention belongs to the technical field of sewage treatment, and in particular relates to a biological adsorption-partial nitrification-anaerobic ammonium oxidation (APnA) process based on a functional carrier. Background Art

[0002] Wastewater, as a carrier of resources and energy, is gaining increasing attention. Efficient, low-carbon wastewater treatment and the development and utilization of wastewater resources and energy have become increasingly crucial, especially since the signing and implementation of the Paris Climate Agreement. Currently, traditional wastewater denitrification processes consume significant amounts of electricity and chemicals, and produce significant amounts of greenhouse gases, failing to meet the requirements of energy recycling and sustainable development.

[0003] Anaerobic ammonium oxidation is an autotrophic denitrification technology that does not require aeration and organic carbon sources. Under anaerobic conditions, anaerobic ammonium oxidizing bacteria (AnAOB) can use NH4 + -N and NO2 - -N directly generates N2, which can theoretically save 100% of the added carbon source and 60% of the aeration volume. At present, this technology is relatively mature in the field of sidestream wastewater denitrification, but there are still certain challenges in its application in mainstream urban sewage. First, the organic matter present in mainstream urban sewage will interfere with the growth of anaerobic ammonium oxidizing bacteria, and urban sewage lacks nitrite nitrogen, the substrate of anaerobic ammonium oxidation reaction, so a partial nitrification stage is required to oxidize part of the ammonia nitrogen into nitrite nitrogen before the subsequent anaerobic ammonium oxidation reaction can be carried out.

[0004] Compared to activated sludge processes, biofilm processes, due to the presence of carriers, can increase sludge age and volumetric loading, effectively enriching anaerobic ammonium-oxidizing (ANAMMOX) bacteria and are an effective means of achieving ANAMMOX in mainstream municipal wastewater. In particular, the moving bed membrane bioreactor (MBMB) based on suspended carriers and the integrated floating-film and activated sludge process based on suspended carriers overcome the drawbacks of fixed biofilm processes, such as low mass transfer efficiency and susceptibility to congestion and agglomeration, and hold great promise for future application. Currently, the most commonly used suspended carriers are primarily polyolefin materials, such as polyethylene and polypropylene, which have high mechanical strength and a density close to that of water. However, due to their material properties, they have poor biocompatibility and lack specific functional design for aerobic and ANAMMOX bacteria. This makes the carriers ineffective in efficiently enriching functional bacteria, such as nitrifying or ANAMMOX bacteria, and enhancing their activity. Therefore, the development of novel biosorption-partial nitrification-ANAMMOX processes based on functional carriers is crucial.

[0005] The present invention proposes a resource and energy recycling and operation mode for a sewage treatment plant, including: 1. converting organic matter in sewage into energy substances, that is, after the organic matter is adsorbed by organisms, the remaining sludge can be used for anaerobic digestion to produce methane and cogeneration of heat and power; 2. achieving efficient denitrification under low aeration and no external carbon source conditions, that is, partial nitrification-anaerobic ammonia oxidation based on functional carriers; 3. reusing the treated high-quality water as a water resource. The present invention provides strong support for achieving the recycling of energy and water resources and sustainable development goals.

[0006] Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide a biosorption-partial nitrification-anaerobic ammonium oxidation (APnA) process based on a functional carrier, which can significantly reduce the emission of aeration and greenhouse gases such as CO2 and N2O while efficiently removing nitrogen.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] The present invention provides a biological adsorption-partial nitrification-anaerobic ammonium oxidation process based on a functional carrier. The processing device of the process mainly includes a water inlet tank, a water inlet pump, a biological adsorption reaction tank, an intermediate sedimentation tank, a partial nitrification reaction tank, an anaerobic ammonium oxidation reaction tank and a secondary sedimentation tank. The water inlet tank is connected to the inlet of the biological adsorption reaction tank through the water inlet pump. The biological adsorption reaction tank is provided with a stirring device. The water outlet of the biological adsorption reaction tank is connected to the inlet of the intermediate sedimentation tank. The sludge return outlet at the bottom of the intermediate sedimentation tank is connected to the sludge return inlet of the biological adsorption reaction tank. The water outlet of the intermediate sedimentation tank is connected to the inlet of the partial nitrification reaction tank. The top of the partial nitrification reaction tank is provided with an aeration device. The aeration device is connected to the aeration disk provided at the bottom of the partial nitrification reaction tank through a pipeline. The partial nitrification reaction tank is filled with a nitrification functional carrier, and the addition amount is 10%-60% of the effective volume of the reactor. The water outlet of the partial nitrification reaction tank is connected to the inlet of the anaerobic ammonia oxidation reaction tank. The anaerobic ammonia oxidation reaction tank is filled with an anaerobic ammonia oxidation functional carrier, and the addition amount is 10%-60% of the effective volume of the reactor. The outlet of the anaerobic ammonia oxidation reaction tank is connected to the inlet of the secondary sedimentation tank.

[0010] The biological adsorption-partial nitrification-anaerobic ammonium oxidation process based on functional carriers comprises the following steps:

[0011] (1) Wastewater enters the biosorption reaction tank from the water inlet tank through the water inlet pump. The biosorption reaction tank is inoculated with activated sludge. The dissolved oxygen in the biosorption reaction tank is controlled to 0.1-0.5 mg / L by a stirring device, the hydraulic retention time is controlled to 10-60 minutes, the sludge concentration is not less than 2000 mg / L, and the sludge return ratio is 10%-60%;

[0012] (2) The effluent from the biological adsorption reaction tank enters a partial nitrification reaction tank, which is inoculated with activated sludge. The dissolved oxygen is controlled at 0.3-2.0 mg / L through hypoxic aeration, the hydraulic retention time is 2-10 h, and the sludge concentration is not less than 2000 mg / L;

[0013] (3) The effluent from part of the nitrification reaction tank enters the anaerobic ammonium oxidation reaction tank, which is inoculated with anaerobic ammonium oxidizing bacteria. The hydraulic retention time is 4-24h, and the sludge concentration is not less than 2000mg / L.

[0014] Based on the above technical solution, further, the anaerobic ammonia oxidation functional carrier is prepared by blending an organic polymer base material with a modified material or / and a functional material, and the added amount of the modified material or / and the functional material does not exceed 10% of the total mass of the carrier; the organic polymer base material is polyethylene or polypropylene; the modified material is a positively charged polymer such as polyquaternary ammonium salt, cationic polyacrylamide, etc.; the functional material is one or a mixture of zero-valent iron, a carbon-based material containing -C=O and -COOH functional groups; the carbon-based material containing -C=O and -COOH functional groups includes graphene oxide and activated carbon and biochar rich in oxygen functional groups or oxidized.

[0015] Based on the above technical solution, further, the nitrating functional carrier is prepared by blending an organic polymer base material with a modifying material or / and a functional material, and the added amount of the modifying material or / and the functional material does not exceed 10% of the total mass of the carrier; the organic polymer base material is polyethylene or polypropylene, the functional material is zeolite, and the modifying material is a positively charged polymer such as polyquaternary ammonium salt, cationic polyacrylamide, etc.

[0016] Based on the above technical solution, further, the anaerobic ammonium oxidation functional carrier and the nitrification functional carrier are prepared by physical blending or screw extrusion process.

[0017] Based on the above technical solution, further, the operating temperature of the biological adsorption reaction tank described in step (1) is room temperature, and the sludge concentration is 2000 mg / L-10000 mg / L.

[0018] Based on the above technical solution, further, the sludge return ratio of the intermediate sedimentation tank is 10%-80%.

[0019] Based on the above technical solution, further, the operating temperature of the partial nitrification reaction tank described in step (2) is not lower than 18° C., and the sludge concentration is 2000 mg / L-8000 mg / L.

[0020] Based on the above technical solution, further, the operating temperature of the anaerobic ammonia oxidation reaction tank described in step (3) is not lower than 18°C, the reactor is controlled to be an anaerobic environment, and the sludge concentration is 2000mg / L-8000mg / L.

[0021] Based on the above technical solution, further, the sludge return ratio of the secondary sedimentation tank is 10%-100%.

[0022] Beneficial effects of the present invention:

[0023] (1) The biosorption tank efficiently adsorbs COD, reducing the effluent COD to less than 50 mg / L, meeting the Class A standard of the Pollutant Discharge Standard for Urban Wastewater Treatment Plants (GB18918-2002). This process saves aeration, reduces CO2 emissions, and provides favorable living conditions for subsequent autotrophic bacteria such as nitrifying bacteria and anaerobic ammonia oxidizing bacteria. The residual sludge after biosorption contains a large amount of organic matter and can be used for anaerobic digestion to produce methane and cogeneration of heat and power.

[0024] (2) The nitrification functional carrier added to the partial nitrification reaction tank is hydrophilic, and the zeolite has the function of adsorbing ammonia, which can enrich ammonia oxidizing bacteria, optimize the bacterial structure in the system and improve the partial nitrification performance of the system, so that the partial nitrification reaction tank can stably provide the reaction substrate nitrite nitrogen for the anaerobic ammonia oxidation reaction tank.

[0025] (3) The anaerobic ammonium oxidation functional carrier added to the anaerobic ammonium oxidation reaction tank, in which zero-valent iron strengthens the anaerobic microenvironment, and iron, as a component of the coenzyme factor heme C of anaerobic ammonium oxidation bacteria, strengthens the proliferation and intracellular metabolic rate of anaerobic ammonium oxidation bacteria. Carbon-based materials containing -C=O functional groups, -COOH functional groups, and conjugated large π bonds mediate the extracellular electron transfer of anaerobic ammonium oxidation bacteria through the cycle of their own oxidation and reduction states, thereby strengthening the extracellular metabolic rate of anaerobic ammonium oxidation bacteria; positively charged polymers such as polyquaternary ammonium salts and cationic polyacrylamide strengthen the biofilm formation performance of anaerobic ammonium oxidation bacteria through electrostatic interaction with microorganisms with negative charges on the surface. These together strengthen the enrichment and biological activity of anaerobic ammonium oxidation bacteria on the carrier, improve the denitrification efficiency of the system, and make the total nitrogen in the effluent meet the Class A standard of the "Pollutant Discharge Standard for Urban Wastewater Treatment Plants" (GB18918-2002). BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention, the drawings related to the embodiments are briefly introduced below.

[0027] Figure 1 is a schematic structural diagram of a biological adsorption-partial nitrification-anaerobic ammonium oxidation (APnA) process reactor based on a functional carrier of the present invention, in which: 1-water inlet tank, 2-water inlet pump, 3-biological adsorption reaction tank, 4-stirring device, 5-intermediate sedimentation tank, 6-partial nitrification reaction tank, 7-aeration device, 8-nitrification functional carrier, 9-aeration plate, 10-insulation device, 11-circulating pump, 12-anaerobic ammonium oxidation reaction tank, 13-anaerobic ammonium oxidation functional carrier, 14-secondary sedimentation tank. Specific embodiments

[0028] The present invention is described in detail below with reference to the embodiments, but the embodiments of the present invention are not limited thereto. Obviously, the embodiments described below are only some embodiments of the present invention. For those skilled in the art, other similar embodiments obtained without creative work all fall within the scope of protection of the present invention.

[0029] Example 1

[0030] Preparation of oxygen-ammonia oxidation functional carrier:

[0031] 1000g of HDPE powder, 10g of polyquaternium salt, and 50g of zero-valent iron were thoroughly mixed in a sealed container to form raw material 1. Raw material 1 was passed through a pelletizer to produce a granular sample. The pelletizer's barrel zone 1 was set at 160°C, the barrel zone 2 was set at 170°C, the barrel zone 3 was set at 180°C, and the die zone was set at 160°C. The strip product extruded from the die was then air-cooled and pelletized to produce a granular sample (referred to as raw material 2). Raw material 2 was passed through an injection molding machine to produce a carrier. The barrel zone 1 was set at 140°C, the barrel zone 2 was set at 150°C, the barrel zone 3 was set at 155°C, and the die zone was set at 140°C. The strip product extruded from the die was then shaped and sized using a vacuum setting sleeve with a vacuum degree of 0.03MPa, cooled with cooling water, and cut into cylindrical products, which were the final anaerobic ammonium oxidation bio-carriers.

[0032] Example 2

[0033] Preparation of nitrification functional carrier:

[0034] 1000g of HDPE powder, 10g of polyquaternium salt, and 30g of zeolite were thoroughly mixed in a sealed container to form raw material 1. Raw material 1 was passed through a granulator to produce a granular sample, wherein the granulator barrel zone 1 was 160°C, the barrel zone 2 was 170°C, the barrel zone 3 was 180°C, and the die zone was 160°C. The strip product extruded from the die head was then air-cooled and pelletized to produce a granular sample (referred to as raw material 2). Raw material 2 was passed through an injection molding machine to produce a carrier, wherein the injection molding machine barrel zone 1 was 140°C, the barrel zone 2 was 150°C, the barrel zone 3 was 155°C, and the die zone was 140°C. The strip product extruded from the die head was then shaped and sized in a vacuum setting sleeve with a vacuum degree of 0.03MPa, cooled with cooling water, and cut into a cylindrical product, namely the nitrified functional carrier.

[0035] Example 3

[0036] The present embodiment provides a biological adsorption-partial nitrification-anaerobic ammonium oxidation process based on a functional carrier, which is carried out using a treatment device as shown in Figure 1. The treatment device mainly includes an inlet tank 1, an inlet pump 2, a biological adsorption reaction tank 3 (diameter 100 mm, height 400 mm, working volume 3 L), an intermediate sedimentation tank 5, a partial nitrification reaction tank 6 (length 100 mm, width 100 mm, height 350 mm, working volume 3 L), an anaerobic ammonium oxidation reaction tank 12 (length 100 mm, width 100 mm, height 350 mm, working volume 3 L) and a secondary sedimentation tank 14. The inlet tank 1 is connected to the inlet of the biological adsorption reaction tank 3 via the inlet pump 2. A stirring device 4 is provided in the biological adsorption reaction tank 3. The water outlet of the biological adsorption reaction tank 3 is connected to the inlet of the intermediate sedimentation tank 5. The sludge return outlet at the bottom of the intermediate sedimentation tank 5 is connected to the sludge return inlet of the biological adsorption reaction tank 3. The water outlet of the intermediate sedimentation tank 5 is connected to the inlet of the partial nitrification reaction tank 6. The top of the partial nitrification reaction tank 6 is provided with an aeration device 7, and the aeration device 7 is connected to the aeration disk 9 provided at the bottom of the partial nitrification reaction tank 6 through a pipeline. The partial nitrification reaction tank 6 is filled with a nitrification functional carrier 8, and the addition amount is 30% of the effective volume of the reactor. The water outlet of the partial nitrification reaction tank 6 is connected to the inlet of the anaerobic ammonium oxidation reaction tank 12, and the anaerobic ammonium oxidation reaction tank 12 is filled with an anaerobic ammonium oxidation functional carrier 13, and the addition amount is 30% of the effective volume of the reactor. The outlet of the anaerobic ammonium oxidation reaction tank 12 is connected to the inlet of the secondary sedimentation tank 14.

[0037] The specific process is as follows:

[0038] (1) Use artificial water distribution to simulate wastewater and pump it into the reactor through the water inlet. The inlet matrix composition is: COD 200mg / L, NH4 + -N 60mg / L, KH2PO4 40mg / L, MgSO4.7H2O 75mg / L, CaCl2.2H2O 45mg / L, NaHCO3 2500mg / L, maintaining the reaction system pH at 7.5. Wastewater enters the biosorption reaction tank 3 from the water inlet tank 1 through the water inlet pump 2. The biosorption reaction tank 3 is inoculated with activated sludge. The dissolved oxygen is controlled at 0.3mg / L by the stirring device 4, the hydraulic retention time is 30min, the sludge concentration is 8500mg / L, and the sludge return ratio is 20%;

[0039] (2) The effluent from the biological adsorption reaction tank 3 enters the partial nitrification reaction tank 6, which is inoculated with activated sludge. The dissolved oxygen is controlled at 1.0 mg / L by hypoxic aeration, the hydraulic retention time is 5 hours, the sludge concentration is 3500 mg / L, and the sludge return ratio is 50%;

[0040] (3) Part of the effluent from the nitrification reaction tank 6 enters the anaerobic ammonium oxidation reaction tank 12, in which anaerobic ammonium oxidizing bacteria are inoculated. The hydraulic retention time is 6 hours, the sludge concentration is 3500 mg / L, and the sludge return ratio is 100%.

[0041] The average COD concentration and NH4 + The -N concentration and TN concentration are 41.5 mg / L, 0.21 mg / L and 14.1 mg / L respectively, which can stably meet the Class A emission standard (GB18918-2002).

[0042] Comparative Example 1

[0043] The specific process is the same as that of Example 1, with the only difference being that no functional carrier is added to the anaerobic ammonium oxidation reaction tank 12 .

[0044] The average COD concentration and NH4 + The -N concentration and TN concentration were 41.5 mg / L, 0.93 mg / L and 21.02 mg / L respectively, which could not meet the Class A emission standard (GB18918-2002).

[0045] Comparative Example 2

[0046] The specific process is the same as that of Example 1, with the only difference being that the anaerobic ammonium oxidation reaction tank 12 is filled with a common HDPE carrier.

[0047] The average COD concentration and NH4 + The -N concentration and TN concentration were 41.5 mg / L, 0.77 mg / L and 18.15 mg / L respectively, which could not meet the Class A emission standard (GB18918-2002).

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A biological adsorption-partial nitrification-anaerobic ammonium oxidation process based on a functional carrier, characterized in that: The treatment device of the process mainly includes an inlet tank, an inlet pump, a biological adsorption reaction tank, an intermediate sedimentation tank, a partial nitrification reaction tank, an anaerobic ammonia oxidation reaction tank and a secondary sedimentation tank. The inlet tank is connected to the inlet of the biological adsorption reaction tank via the inlet pump. A stirring device is arranged in the biological adsorption reaction tank. The water outlet of the biological adsorption reaction tank is connected to the inlet of the intermediate sedimentation tank. The sludge return outlet at the bottom of the intermediate sedimentation tank is connected to the sludge return inlet of the biological adsorption reaction tank. The water outlet of the intermediate sedimentation tank is connected to the inlet of the partial nitrification reaction tank. An aeration device is provided on the top of the partial nitrification reaction tank, and the aeration device is connected to an aeration disk provided at the bottom of the partial nitrification reaction tank through a pipeline. The partial nitrification reaction tank is filled with a nitrification functional carrier, and the dosage is 10%-60% of the effective volume of the reactor. The water outlet of the partial nitrification reaction tank is connected to the inlet of the anaerobic ammonium oxidation reaction tank. The anaerobic ammonium oxidation reaction tank is filled with an anaerobic ammonium oxidation functional carrier, and the dosage is 10%-60% of the effective volume of the reactor. The outlet of the anaerobic ammonium oxidation reaction tank is connected to the inlet of the secondary sedimentation tank; The steps include: (1) Wastewater enters the biosorption reaction tank from the water inlet tank through the water inlet pump. The biosorption reaction tank is inoculated with activated sludge. The dissolved oxygen in the biosorption reaction tank is controlled to be 0.1-0.5 mg / L through a stirring device, the hydraulic retention time is controlled to be 10-60 min, the sludge concentration is not less than 2000 mg / L, and the sludge return ratio is 10%-60%; (2) The effluent from the biological adsorption reaction tank enters a partial nitrification reaction tank, in which activated sludge is inoculated, and the dissolved oxygen is controlled to 0.3-2.0 mg / L through low oxygen aeration, the hydraulic retention time is 2-10 h, and the sludge concentration is not less than 2000 mg / L; (3) The effluent from part of the nitrification reaction tank enters the anaerobic ammonium oxidation reaction tank, which is inoculated with anaerobic ammonium oxidizing bacteria, with a hydraulic retention time of 4-24h and a sludge concentration of not less than 2000mg / L.

2. The process according to claim 1, characterized in that The anaerobic ammonia oxidation functional carrier is prepared by blending an organic polymer base material with a modified material or / and a functional material, wherein the added amount of the modified material or / and the functional material does not exceed 10% of the total mass of the carrier; the organic polymer base material is polyethylene or polypropylene; the modified material is a positively charged polymer such as a polyquaternary ammonium salt, a cationic polyacrylamide, etc.; the functional material is one or a mixture of zero-valent iron, a carbon-based material containing -C=O and -COOH functional groups; the carbon-based material containing -C=O and -COOH functional groups includes graphene oxide and activated carbon and biochar rich in oxygen-containing functional groups or oxidized.

3. The process according to claim 1, characterized in that The nitration functional carrier is prepared by blending an organic polymer base material with a modified material or / and a functional material, and the added amount of the modified material or / and the functional material does not exceed 10% of the total mass of the carrier; the organic polymer base material is polyethylene or polypropylene, the functional material is zeolite, and the modified material is a positively charged polymer such as polyquaternary ammonium salt, cationic polyacrylamide, etc.

4. The process according to claim 2 or 3, characterized in that The anaerobic ammonium oxidation functional carrier and the nitrification functional carrier are prepared by physical blending or screw extrusion process.

5. The process according to claim 1, characterized in that The operating temperature of the biological adsorption reaction tank described in step (1) is room temperature, and the sludge concentration is 2000mg / L-10000mg / L.

6. The process according to claim 1, characterized in that The sludge return ratio of the intermediate sedimentation tank is 10%-80%.

7. The process according to claim 1, characterized in that The operating temperature of the partial nitrification reaction tank described in step (2) is not less than 18° C., and the sludge concentration is 2000 mg / L-8000 mg / L.

8. The process according to claim 1, characterized in that The operating temperature of the anaerobic ammonium oxidation reaction tank described in step (3) is not less than 18° C., and the reactor is controlled to be an anaerobic environment with a sludge concentration of 2000 mg / L-8000 mg / L.

9. The process according to claim 1, characterized in that The sludge return ratio of the secondary sedimentation tank is 10%-100%.

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