A method for simultaneously treating nitrate wastewater and domestic sewage using an integrated short-cut denitrification / anaerobic ammonium oxidation process with zeolite packing.

Abstract

This invention discloses a method for simultaneously treating nitrate wastewater and domestic sewage using an integrated short-cut denitrification / anaerobic ammonium oxidation process with zeolite packing. The apparatus includes an influent tank, a zeolite-short-cut denitrification simultaneous anaerobic ammonium oxidation reactor, and an effluent tank. This invention utilizes the characteristic of zeolite to adsorb ammonia nitrogen in high-ammonia-nitrogen environments and desorb ammonia nitrogen in low-ammonia-nitrogen environments, maintaining a relatively stable ammonia-nitrogen concentration around the carrier and providing a suitable environment for anaerobic ammonium oxidation. Simultaneously, nitrate nitrogen in the influent is converted into nitrite nitrogen by short-cut denitrifying bacteria, providing a stable nitrite nitrogen substrate for anaerobic ammonium oxidation bacteria, achieving deep denitrification of wastewater. This invention utilizes zeolite to enrich short-cut denitrification and anaerobic ammonium oxidation bacteria, achieving simultaneous treatment of nitrate wastewater and domestic sewage, which is of great significance for achieving sustainable wastewater treatment.

Description

Technical Field

[0001] The present invention relates to a method for simultaneously treating nitrate wastewater and domestic sewage using an integrated short-cut denitrification / anaerobic ammonia oxidation process with zeolite packing, which belongs to the field of wastewater biological treatment technology. Background Technology

[0002] Traditional wastewater treatment processes often suffer from problems such as low treatment efficiency, high energy consumption, and large amounts of residual sludge when treating nitrate wastewater and domestic sewage.

[0003] With the advent of the concepts of carbon peaking and carbon neutrality, the development of green and low-carbon wastewater treatment technologies has become a research hotspot. Anaerobic ammonia oxidation (AAO) can achieve energy-saving and low-carbon wastewater treatment, offering numerous advantages including no need for aeration, no additional carbon source, low sludge production, and no greenhouse gas emissions. However, a series of issues, such as the environmental sensitivity of AAO bacteria and their long growth cycle, limit its application in practical wastewater treatment. Currently, providing a stable source of nitrite nitrogen for AAO is a key issue restricting its development.

[0004] Short-cut denitrification can provide a stable source of nitrite nitrogen for anaerobic ammonia oxidation. By using short-cut denitrifying bacteria to pretreat nitrate wastewater, nitrate nitrogen is converted into nitrite nitrogen, providing a substrate for anaerobic ammonia oxidation. As heterotrophic bacteria, short-cut denitrifying bacteria can maintain the stability of the system.

[0005] Zeolite, as a porous mineral, has the ability to remove ammonia nitrogen from wastewater. Its abundant pore structure provides a stable living environment for anaerobic ammonia oxidizing bacteria. Furthermore, zeolite's excellent adsorption and desorption properties allow it to adsorb ammonia nitrogen at high concentrations and desorb it at low concentrations, providing a stable ammonia nitrogen environment for anaerobic ammonia oxidation. This enables efficient enrichment of anaerobic ammonia oxidizing bacteria and promotes the synergistic coexistence of short-range denitrifying bacteria and anaerobic ammonia oxidizing bacteria, achieving simultaneous treatment of nitrate wastewater and domestic sewage.

[0006] Therefore, the zeolite-short-cut denitrification coupled with anaerobic ammonia oxidation (Z-PN / A) technology can achieve stable nitrogen removal and can simultaneously remove ammonia nitrogen and nitrate in the same reactor, resulting in significant environmental and economic benefits. Summary of the Invention

[0007] This invention proposes an apparatus and method for simultaneously treating nitrate wastewater and domestic sewage using an integrated short-cut denitrification / anaerobic ammonium oxidation process with zeolite packing. This method combines the adsorption properties of zeolite packing with biofilm technology to simultaneously achieve coupled denitrification of nitrates and anaerobic ammonium oxidation. This results in highly efficient denitrification with a total nitrogen concentration of less than 15 mg / L in the effluent, even when domestic sewage and nitrate wastewater are used as influent. This is of great significance for achieving sustainable wastewater treatment.

[0008] To achieve the above objectives, the present invention provides an apparatus for simultaneously treating nitrate wastewater and domestic sewage using an integrated short-cut denitrification / anaerobic ammonium oxidation process with zeolite packing, comprising an inlet tank, a zeolite-short-cut denitrification simultaneous anaerobic ammonium oxidation reactor, and an outlet tank; the inlet tank and the zeolite-short-cut denitrification simultaneous anaerobic ammonium oxidation reactor are connected by an inlet pump.

[0009] Preferably, the zeolite-short-cut denitrification simultaneous anaerobic ammonium oxidation reactor is equipped with an inlet at the bottom, and a water tank for mixing nitrate and domestic sewage is located near the inlet, with a heating device installed in the water tank.

[0010] Preferably, the zeolite-short-cut denitrification simultaneous anaerobic ammonium oxidation reactor has a drain outlet on the upper side away from the inlet, and an outlet water tank is located near the drain outlet.

[0011] Preferably, the zeolite-short-cut denitrification simultaneous anaerobic ammonium oxidation reactor is equipped with a reflux outlet and a reflux inlet, and a reflux pump is provided between the reflux outlet and the reflux inlet; The zeolite-short-cut denitrification simultaneous anaerobic ammonium oxidation reactor is equipped with a pH / DO meter.

[0012] A method for simultaneously treating nitrate wastewater and domestic sewage using an integrated short-cut denitrification / anaerobic ammonia oxidation process with zeolite packing includes the following steps: Step S1: Start-up and stable operation of the anaerobic ammonia oxidation reactor: Step S11: Inoculate the anaerobic ammonia oxidation reactor with anaerobic ammonia oxidation granular sludge and control the sludge concentration in the reactor at 3-4 g / L; Step S12: The anaerobic ammonia oxidation reactor uses domestic sewage and artificially prepared water containing nitrite nitrogen as influent, with an ammonia nitrogen concentration of 30-80 mg / L and the nitrite nitrogen concentration controlled to be 1-1.5 times that of ammonia nitrogen; the influent temperature is controlled within the range of 30-35℃ using heating rods. Step S13: The pH of the influent to the anaerobic ammonia oxidation reactor is 7-8; the hydraulic retention time is controlled at 12-18h; the reflux pump controls the reflux ratio at 300%-400% to ensure sufficient contact between mud and water. When the concentrations of nitrite nitrogen and ammonia nitrogen in the effluent are both less than 5 mg / L and the total nitrogen removal rate is stable at over 70%, it indicates that the anaerobic ammonia oxidation has been successfully started. Step S2: Start-up and stable operation of the zeolite-anaerobic ammonia oxidation reactor; Step S3: Start-up of zeolite-short-cut denitrification simultaneous anaerobic ammonium oxidation and realization of deep nitrogen removal.

[0013] Preferably, step S2 specifically involves: Step S21: Add 1-2 mm zeolite packing material to the zeolite-anaerobic ammonia oxidation reactor at a feed ratio of 60%-80%; The zeolite-anaerobic ammonia oxidation reactor uses domestic sewage and artificially prepared water containing nitrite nitrogen as influent, with an ammonia nitrogen concentration of 30-80 mg / L and the nitrite nitrogen concentration controlled at 1-1.5 times the ammonia nitrogen concentration. The influent temperature is controlled within the range of 30-35℃ using heating rods. The reflux pump controls the reflux ratio at 300%-400% to ensure sufficient contact between sludge and water. The sludge concentration in the zeolite-anaerobic ammonia oxidation reactor is 3-4 g / L; the influent pH is in the range of 7-8; and the hydraulic retention time is controlled at 12-18 h. Step S22: When the concentrations of nitrite nitrogen and ammonia nitrogen in the effluent are both less than 5 mg / L, and the total nitrogen removal rate is stable at over 70%, and microbial enrichment can be observed on the zeolite packing under a microscope, and an anaerobic ammonia oxidation specific activity test is conducted, it indicates that a biofilm has been formed on the zeolite.

[0014] Preferably, step S3 specifically involves: Step S31: The zeolite-short-cut denitrification simultaneous anaerobic ammonia oxidation reactor uses domestic sewage and nitrate wastewater as influent, with an ammonia nitrogen concentration of 30-80 mg / L and a nitrate nitrogen concentration of 50-100 mg / L. The influent temperature is controlled within the range of 30-35℃ using heating rods. In addition, if the effluent ammonia nitrogen is greater than 5 mg / L and the carbon source is depleted, additional carbon source needs to be added to maintain the short-cut denitrification activity. The hydraulic retention time of the zeolite-short-cut denitrification simultaneous anaerobic ammonium oxidation reactor is controlled at 12-18 h; the reflux pump controls the reflux ratio at 300%-400%. Step S32: When the ammonia nitrogen concentration in the effluent of the zeolite-short-cut denitrification simultaneous anaerobic ammonia oxidation reactor is <1 mg / L and the total nitrogen removal rate is higher than 90%, the coupling of zeolite-short-cut denitrification simultaneous anaerobic ammonia oxidation is realized, achieving efficient nitrogen removal.

[0015] The present invention provides an apparatus and method for simultaneously treating nitrate wastewater and domestic sewage using an integrated short-cut denitrification / anaerobic ammonia oxidation process with the aforementioned zeolite packing material. The beneficial effects are as follows: Zeolite can perform ion exchange with ammonia nitrogen ions, selectively adsorbing ammonia nitrogen and thus creating a high-ammonia-nitrogen microenvironment around the zeolite. It can also desorb ammonia nitrogen in low-ammonia-nitrogen environments, providing a stable environment for enrichment during anaerobic ammonia oxidation. The rough and porous surface of zeolite is conducive to the attachment of anaerobic ammonia-oxidizing bacteria. After attachment, these bacteria can utilize the ammonia nitrogen desorbed from the zeolite for their life activities, maintaining stable anaerobic ammonia oxidation activity and achieving efficient nitrogen removal. Short-cut denitrifying bacteria utilize nitrate nitrogen in the influent and carbon sources in domestic sewage for their life activities. The nitrite nitrogen produced by the reaction can not only provide a stable substrate for anaerobic ammonium oxidation, but also reduce the nitrate nitrogen generated by anaerobic ammonium oxidation, thus achieving simultaneous removal of nitrate nitrogen and ammonia nitrogen, improving the total nitrogen removal rate, and achieving efficient nitrogen removal. In this invention, anaerobic ammonia oxidizing bacteria are enriched using zeolite. Zeolite, as a functional carrier, facilitates the enrichment of anaerobic ammonia oxidation and can desorb ammonia nitrogen at low ammonia nitrogen concentrations, maintaining a relatively stable ammonia nitrogen concentration in the water and providing a good growth environment for anaerobic ammonia oxidizing bacteria. It can save system start-up time while improving the stability of initial denitrification performance. The zeolite added in this invention has dual functions of adsorption and carrier, and is inexpensive, thus reducing the overall operating cost of the process.

[0016] In this invention, zeolite packing can promote the retention and enrichment of anaerobic ammonia oxidizing bacteria and short-range denitrifying bacteria, solving the problem of slow growth of anaerobic ammonia oxidizing bacteria and achieving a more efficient denitrification effect. The integrated short-cut denitrification / anaerobic ammonium oxidation UASB in this invention is easy to operate and saves floor space; The integrated short-cut denitrification / anaerobic ammonium oxidation in this invention can simultaneously treat domestic sewage and nitrate wastewater, improve nitrogen removal efficiency, save additional energy consumption, and protect the environment. The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] Figure 1 Schematic diagram of a device for simultaneously treating nitrate wastewater and domestic sewage using an integrated short-cut denitrification / anaerobic ammonium oxidation process with zeolite packing:

[0018] Attached Figure

[0019] 1-Inlet water tank; 1.1-Heating rod; 1.2-Peristaltic pump; Zeolite-short-cut denitrification simultaneous anaerobic ammonium oxidation reactor; 2.1-inlet, 2.2-outlet, 2.3-zeolite packing, 2.4-pH / DO online detector, 2.5-reflux pump, 2.6-reflux outlet, 2.7-reflux inlet; Water outlet tank. Detailed Implementation

[0020] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples: like Figure 1As shown, an apparatus for simultaneously treating nitrate wastewater and domestic sewage using an integrated short-cut denitrification / anaerobic ammonium oxidation process with zeolite packing includes an inlet tank 1, a zeolite-denitrification simultaneous anaerobic ammonium oxidation reactor 2, and an outlet tank 3; the inlet tank 1 and the zeolite-short-cut denitrification simultaneous anaerobic ammonium oxidation reactor 2 are connected by an inlet pump 1.2.

[0021] The zeolite-short-cut denitrification simultaneous anaerobic ammonia oxidation reactor 2 is equipped with an inlet 2.1 at the bottom. Near the inlet 2.1, there is a nitrate and domestic sewage mixed water tank 1, which is equipped with a heating device 1.1.

[0022] The zeolite-short-cut denitrification simultaneous anaerobic ammonia oxidation reactor 2 has an outlet 2.2 on the upper side away from the inlet, and an outlet water tank 3 is located near the outlet 2.2.

[0023] The zeolite-short-cut denitrification simultaneous anaerobic ammonia oxidation reactor 2 is equipped with a reflux outlet 2.6 and a reflux inlet 2.7, and a reflux pump 2.5 is installed between the reflux outlet 2.6 and the reflux inlet 2.7; The zeolite-short-path denitrification simultaneous anaerobic ammonia oxidation reactor is equipped with a pH / DO meter 2.4. Example

[0024] A short-cut denitrification / anaerobic ammonium oxidation process using zeolite packing material was constructed to simultaneously treat nitrate wastewater and domestic sewage, according to the following method: Step S1: Start-up and stable operation of anaerobic ammonia oxidation reactor 2: Step S11: Inoculate anaerobic ammonia oxidation granular sludge into anaerobic ammonia oxidation reactor 2, and control the sludge concentration in the reactor to be 3-4 g / L.

[0025] Step S12: Anaerobic ammonia oxidation reactor 2 uses domestic sewage from the staff quarters of Beijing University of Technology and artificially prepared water containing nitrite nitrogen as influent. The ammonia nitrogen concentration is 70-80 mg / L, and the nitrite nitrogen concentration is controlled to be 1.5 times the ammonia nitrogen concentration. The influent temperature is controlled within the range of 30-35℃ using heating rods.

[0026] Step S13: The pH of the influent to the anaerobic ammonia oxidation reactor 2 is 7-8; the hydraulic retention time is controlled at 14h; the reflux pump controls the reflux ratio at 300%-400% to ensure sufficient contact between mud and water. When the concentrations of nitrite nitrogen and ammonia nitrogen in the effluent are both less than 5 mg / L and the total nitrogen removal rate is stable at over 70%, the anaerobic ammonia oxidation is successfully started.

[0027] Step S2: Start-up and stable operation of zeolite-anaerobic ammonia oxidation reactor 2; Step S21: Add 1-2 mm zeolite packing material to the zeolite-anaerobic ammonia oxidation reactor at a feed ratio of 60%.

[0028] The zeolite-anaerobic ammonia oxidation reactor uses domestic sewage and artificially prepared water containing nitrite nitrogen as influent, with an ammonia nitrogen concentration of 70-80 mg / L and the nitrite nitrogen concentration controlled at 1.5 times the ammonia nitrogen concentration. The influent temperature is controlled within the range of 30-35℃ by heating rods. The reflux pump controls the reflux ratio at 300%-400% to ensure full contact between sludge and water.

[0029] The sludge concentration in the zeolite-anaerobic ammonia oxidation reactor is 3-4 g / L; the influent pH is in the range of 7-8; and the hydraulic retention time is controlled at 14 h.

[0030] Step S22: When the concentrations of nitrite nitrogen and ammonia nitrogen in the effluent are both less than 5 mg / L and the total nitrogen removal rate is stable at over 70%, brownish-red bacterial communities can be observed attached to the zeolite packing with the naked eye. The bacterial communities can be observed under a microscope, and the anaerobic ammonia oxidation specific activity test shows good performance, indicating that a biofilm has been formed on the zeolite.

[0031] Step S3: Start-up of zeolite-short-cut denitrification simultaneous anaerobic ammonium oxidation and realization of deep nitrogen removal: Step S31: The zeolite-short-cut denitrification simultaneous anaerobic ammonia oxidation reactor uses domestic sewage and nitrate wastewater as influent, with an ammonia nitrogen concentration of 70-80 mg / L and a nitrate nitrogen concentration of 90-100 mg / L; the influent temperature is controlled within the range of 30-35℃ using heating rods.

[0032] The hydraulic retention time of the zeolite-short-cut denitrification simultaneous anaerobic ammonia oxidation reactor is controlled at 14 hours; the reflux pump controls the reflux ratio at 300%-400%.

[0033] Step S32: When the ammonia nitrogen concentration in the effluent of the zeolite-short-cut denitrification simultaneous anaerobic ammonia oxidation reactor is less than 1 mg / L and the total nitrogen removal rate is higher than 90%, the coupling of zeolite-short-cut denitrification simultaneous anaerobic ammonia oxidation is realized, achieving efficient nitrogen removal.

[0034] Therefore, this invention employs the aforementioned apparatus and method for simultaneously treating nitrate wastewater and domestic sewage using an integrated short-cut denitrification / anaerobic ammonia oxidation process with zeolite packing. Zeolite serves as a functional carrier, adsorbing ammonia nitrogen at high concentrations and desorbing it at low concentrations, thus providing a stable substrate for anaerobic ammonia oxidation. The nitrite nitrogen generated by the short-cut denitrifying bacteria provides a stable substrate supply for the life activities of the anaerobic ammonia oxidizing bacteria. Furthermore, zeolite acts as a carrier, providing a stable environment for the enrichment of anaerobic ammonia nitrogen. This constructs a zeolite-short-cut denitrification synchronous anaerobic ammonia oxidation reaction system, enabling the simultaneous treatment of nitrate wastewater and domestic sewage. This system is suitable for deep denitrification of wastewater and is of great significance for achieving sustainable wastewater treatment.

[0035] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for simultaneously treating nitrate wastewater and domestic sewage using an integrated short-cut denitrification / anaerobic ammonium oxidation process with zeolite packing, characterized in that: The apparatus used in this method includes an inlet tank, a zeolite-short-cut denitrification simultaneous anaerobic ammonium oxidation reactor, and an outlet tank. The inlet tank and the zeolite-short-cut denitrification simultaneous anaerobic ammonium oxidation reactor are connected by an inlet pump. The zeolite-short-cut denitrification simultaneous anaerobic ammonium oxidation reactor is equipped with a reflux outlet and a reflux inlet, and a reflux pump is installed between the reflux outlet and the reflux inlet. The zeolite-short-cut denitrification simultaneous anaerobic ammonium oxidation reactor is equipped with a pH / DO meter. The zeolite-short-cut denitrification simultaneous anaerobic ammonium oxidation reactor is a UASB reactor. The zeolite-short-cut denitrification simultaneous anaerobic ammonium oxidation reactor has an inlet at the bottom, and an inlet water tank for mixing nitrate wastewater and domestic sewage is set up near the inlet. The inlet water tank is equipped with a heating device. The zeolite-short-cut denitrification simultaneous anaerobic ammonium oxidation reactor has a drain outlet on one side of its upper end, away from the inlet, and this drain outlet is connected to the effluent tank. Its characteristic is that it includes the following steps: Step S1, Start-up and stable operation of anaerobic ammonium oxidation: Step S11: Inoculate the anaerobic ammonia oxidation reactor with anaerobic ammonia oxidation granular sludge and control the sludge concentration in the reactor at 3-4 g / L; Step S12: The anaerobic ammonia oxidation reactor uses domestic sewage and artificially prepared water containing nitrite nitrogen as influent, with an ammonia nitrogen concentration of 30-80 mg / L and the nitrite nitrogen concentration controlled to be 1-1.5 times that of ammonia nitrogen. The influent temperature is controlled within the range of 30-35℃ using heating rods. Step S13: The pH of the influent to the anaerobic ammonia oxidation reactor is 7-8; the hydraulic retention time is controlled at 12-18h; the reflux pump controls the reflux ratio at 300%-400% to ensure sufficient contact between mud and water. When the concentrations of nitrite nitrogen and ammonia nitrogen in the effluent are both less than 5 mg / L and the total nitrogen removal rate is stable at over 70%, the anaerobic ammonia oxidation is successfully started. Step S2: Start-up and stable operation of the zeolite-anaerobic ammonia oxidation reactor; Step S3: Start-up of zeolite-short-cut denitrification simultaneous anaerobic ammonium oxidation and realization of deep nitrogen removal; Step S2 specifically involves: Step S21: Add 1-2 mm zeolite packing material to the zeolite-anaerobic ammonia oxidation reactor at a feed ratio of 60%-80%; The zeolite-anaerobic ammonia oxidation reactor uses domestic sewage and artificially prepared water containing nitrite as influent, with an ammonia nitrogen concentration of 30-80 mg / L and a nitrite nitrogen concentration controlled at 1-1.5 times the ammonia nitrogen concentration. The influent temperature is controlled within the range of 30-35℃ using heating rods. The reflux pump controls the reflux ratio at 300%-400% to ensure sufficient contact between sludge and water. The sludge concentration in the zeolite-anaerobic ammonia oxidation reactor is 3-4 g / L. The influent pH is within the range of 7-8. The hydraulic retention time is controlled at 12-18 h. Step S22: When the concentrations of nitrite nitrogen and ammonia nitrogen in the effluent are both <5 mg / L and the total nitrogen removal rate is stable at over 70%, and microbial enrichment is observed on the zeolite packing under a microscope, and the anaerobic ammonia oxidation specific activity test is conducted, a biofilm has been formed on the zeolite. Step S3 specifically involves: Step S31: The zeolite-short-cut denitrification simultaneous anaerobic ammonia oxidation reactor uses domestic sewage and nitrate wastewater as influent, with an ammonia nitrogen concentration of 30-80 mg / L and a nitrate nitrogen concentration of 50-100 mg / L. The influent temperature is controlled within the range of 30-35℃ using heating rods. In addition, if the effluent ammonia nitrogen is greater than 5 mg / L and the carbon source is depleted, additional carbon source needs to be added to maintain the short-cut denitrification activity. The hydraulic retention time of the zeolite-short-cut denitrification simultaneous anaerobic ammonium oxidation reactor is controlled at 12-18 h; the reflux pump controls the reflux ratio at 300%-400%. Step S32: When the ammonia nitrogen concentration in the effluent of the zeolite-short-cut denitrification simultaneous anaerobic ammonia oxidation reactor is <1 mg / L and the total nitrogen removal rate is higher than 90%, the coupling of zeolite-short-cut denitrification simultaneous anaerobic ammonia oxidation is realized, achieving efficient nitrogen removal.

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