Technology for treating high-ammonia-nitrogen organic wastewater through anoxic preposed double short-range coupling anaerobic ammonia oxidation

Abstract

The invention discloses a technology for treating high-ammonia-nitrogen wastewater through anaerobic preposed double short-range coupling anaerobic ammonia oxidation (ADSA), and belongs to the field of wastewater treatment. The technical process comprises an anoxic zone, an anaerobic ammonia oxidation zone and a mud-water separation zone. High-ammonia-nitrogen wastewater is subjected to anaerobic pretreatment to remove most organic pollutants and then enters an anoxic zone, main functional bacteria of the anoxic zone are denitrifying bacteria and anaerobic ammonium oxidation bacteria, the denitrifying bacteria fully utilize residual organic carbon sources in the wastewater and nitrate nitrogen in internal reflux to perform short-cut denitrification, nitrate nitrogen is converted into nitrite nitrogen, and the nitrite nitrogen is converted into nitrite nitrogen; under the action of anaerobic ammonium oxidation bacteria, ammonia nitrogen in the raw water reacts with nitrite nitrogen generated by short-cut denitrification to generate nitrogen; after being treated by the anoxic section, the wastewater further enters an anaerobic ammonium oxidation zone, main functional bacteria in the anaerobic ammonium oxidation zone are short-cut nitrifying bacteria and anaerobic ammonium oxidation bacteria, ammonia nitrogen in the raw water is partially converted into nitrite nitrogen under the action of the ammonia oxidation bacteria, and the generated nitrite nitrogen and residual ammonia nitrogen generate nitrogen under the action of the anaerobic ammonium oxidation bacteria; nitrate nitrogen generated in the reaction process flows back to the front anoxic zone through an internal reflux system for deep denitrification; finally, the purified water is subjected to sludge-water separation through a sedimentation tank and then is discharged after reaching the standard.

Description

Technical Field

[0001] The present invention relates to the field of biological wastewater treatment, and particularly to a device and technology for treating high-ammonia-nitrogen organic wastewater by anoxic pre-positioned dual-shortcut coupled anaerobic ammonium oxidation. Background Art

[0002] With the rapid development of industry, the discharge of wastewater containing high ammonia nitrogen and high organic pollutants is increasing day by day, which poses a great potential harm to the ecological environment. Correspondingly, the environmental quality standards and water pollutant discharge standards are becoming increasingly strict. At present, the problems of low total nitrogen removal rate, high energy consumption, and the need to consume a large amount of carbon source in traditional biological treatment processes have hindered the efficient treatment of industrial wastewater. Therefore, the development and application of high-efficiency and low-energy-consuming biological nitrogen removal technologies are imperative.

[0003] Compared with the traditional nitrification-denitrification nitrogen removal (AO) method, anaerobic ammonium oxidation has the advantages of low aeration energy consumption, autotrophic throughout the process without the need for a carbon source, less sludge production, and high nitrogen removal efficiency. It can greatly reduce the demand for carbon source and energy, and has become a hot spot in the field of biological wastewater treatment. Anaerobic ammonium oxidation is an autotrophic biological nitrogen removal process in which ammonia nitrogen is used as an electron donor and nitrite nitrogen is used as an electron acceptor to convert the two nitrogen species into nitrogen gas and a part of nitrate nitrogen.

[0004] In engineering applications, a certain amount of nitrate nitrogen will be generated in the anaerobic ammonium oxidation process. Usually, it is necessary to couple AO at the back end to form an "anaerobic ammonium oxidation + AO" technical process to achieve effective nitrogen removal. However, this technical process requires the addition of an external carbon source to achieve deep nitrogen removal, and the process route is long.

[0005] This technology pre-positions anoxia in the anaerobic ammonium oxidation section and organically couples anaerobic ammonium oxidation with short-cut denitrification and short-cut nitrification to form an anoxic pre-positioned dual-shortcut coupled anaerobic ammonium oxidation technology (ADSA). It can make full use of the organic carbon source in the influent to achieve high-efficiency nitrogen removal without the need to add an additional organic carbon source, shorten the long process flow, and at the same time, the pre-positioned anoxia can serve as a buffer zone for the main reaction area of anaerobic ammonium oxidation at the back end, reducing the impact of the influent on anaerobic ammonium oxidation and improving the system stability. Summary of the Invention

[0006] The present invention proposes a technical process for treating high-ammonia-nitrogen wastewater by anoxic pre-positioned dual-shortcut coupled anaerobic ammonium oxidation. This method can make full use of the organic carbon source in the influent to achieve high-efficiency nitrogen removal without the need to add an additional organic carbon source, shorten the long process flow, and at the same time, the pre-positioned anoxia can serve as a buffer zone for the main reaction area of anaerobic ammonium oxidation at the back end, reducing the impact of the influent on anaerobic ammonium oxidation and improving the system stability to achieve deep nitrogen removal.

[0007] The object of the present invention is achieved through the following technical solutions:

[0008] A technology process for treating high-ammonia-nitrogen wastewater by anoxic pre-positioned dual short-cut coupled anaerobic ammonium oxidation is characterized in that it includes an anoxic zone, an anaerobic ammonium oxidation zone, and a sludge-water separation zone, and an internal reflux is set between the anaerobic ammonium oxidation zone and the anoxic zone.

[0009] Further, the anoxic zone is placed at the front end of the anaerobic ammonium oxidation zone. The main functional bacteria in the anoxic zone are denitrifying bacteria and anaerobic ammonium oxidizing bacteria; the denitrifying bacteria use the nitrate nitrogen in the reflux liquid of the anaerobic ammonium oxidation zone as the electron acceptor and the remaining organic matter in the raw water as the electron donor for short-cut denitrification, converting nitrate nitrogen into nitrite nitrogen. At the same time, under the action of anaerobic ammonium oxidizing bacteria, the nitrite nitrogen reacts with part of the ammonia nitrogen in the raw water to generate nitrogen gas.

[0010] Further, the anaerobic ammonium oxidation zone is a sludge-film symbiotic system, mainly including biological fillers, aeration, and reflux systems. The main functional bacteria are ammonia-oxidizing bacteria and anaerobic ammonium oxidizing bacteria. The ammonia-oxidizing bacteria carry out short-cut nitrification on part of the ammonia nitrogen, converting ammonia nitrogen into nitrite nitrogen. Further, under the action of anaerobic ammonium oxidizing bacteria, the remaining ammonia nitrogen reacts with nitrite nitrogen to generate nitrogen gas.

[0011] Further, the anoxic zone has a multi-functional effect. It can not only make full use of the organic carbon source in the wastewater, reduce the impact of organic matter on the subsequent anaerobic ammonium oxidation, but also serve as a safety buffer zone for the subsequent anaerobic ammonium oxidation to cope with fluctuating water quality, improving the overall stability of the system.

[0012] Further, the biological fillers are fixed biological fillers; the reflux system returns the nitrate nitrogen generated in the anaerobic ammonium oxidation process to the front anoxic section for deep denitrification by means of a small proportion of internal reflux; the aeration system is micro-aeration, and its main function is to provide oxygen and stirring function for short-cut nitrification.

[0013] Therefore, the beneficial effects of the technology process for treating high-ammonia-nitrogen wastewater by anoxic pre-positioned dual short-cut coupled anaerobic ammonium oxidation provided by the present invention are as follows:

[0014] (1) By placing the anoxic zone at the front end of the anaerobic ammonium oxidation zone and through the reflux system, the present invention can serve as a safety buffer zone for anaerobic ammonium oxidation, improving the overall stability of the system.

[0015] (2) By returning the mixed liquid of the anaerobic ammonium oxidation zone to the front anoxic zone and carrying out short-cut denitrification reaction in the anoxic zone, the present invention converts the nitrate nitrogen in the reflux liquid of the anaerobic ammonium oxidation zone into nitrite nitrogen, providing a reaction substrate for the anaerobic ammonium oxidation reaction.

[0016] (3) The present invention utilizes the anaerobic ammonium oxidizing bacteria in the reflux mixed liquid to carry out ammonia oxidation reaction in the pre-positioned anoxic zone, making full use of the organic carbon source in the wastewater and reducing the impact of organic matter on the subsequent anaerobic ammonium oxidation.

[0017] (4) In the present invention, the short-cut nitrification reaction and the anaerobic ammonium oxidation reaction are carried out simultaneously in the anaerobic ammonium oxidation zone to achieve efficient nitrogen removal from high-ammonia-nitrogen wastewater. Description of the Drawings

[0018] Figure 1 It is the nitrogen removal performance diagram of the process for treating high-ammonia-nitrogen wastewater by the process of preposing anoxic zone and coupling double short-cut with anaerobic ammonium oxidation according to the present invention;

[0019] Figure 2 It is the process flow diagram of the treatment of high-ammonia-nitrogen organic wastewater of a certain chemical enterprise in Example 1;

[0020] Figure 3 It is the process flow diagram of the treatment of leachate from a certain domestic waste landfill in Example 2. Detailed Embodiments

[0021] The following introduces multiple preferred embodiments of the present invention with reference to the accompanying drawings of the specification to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0022] Application Example 1 Treatment of High-Ammonia-Nitrogen Organic Chemical Wastewater of a Certain Chemical Enterprise

[0023] The wastewater is taken from the mixed wastewater of the production line wastewater and the laboratory wastewater of a certain chemical enterprise. Since the concentration of refractory pollutants in the wastewater is relatively high, the ozone advanced oxidation method and the anaerobic method are first used to decompose the refractory pollutants in the mixed wastewater, remove part of the COD and organic nitrogen, and then the process of preposing anoxic zone and coupling double short-cut with anaerobic ammonium oxidation is used to treat the mixed wastewater. The specific process flow is shown in Figure 2 , and the content changes of pollutants in the mixed wastewater before and after treatment are shown in Table 1.

[0026] Table 1. Content change table of pollutants in the mixed wastewater before and after treatment by the process of preposing anoxic zone and coupling double short-cut with anaerobic ammonium oxidation

[0027]

[0028] As can be seen from the above table, before the treatment of high-ammonia-nitrogen organic wastewater by the method of preposing anoxic zone and coupling double short-cut with anaerobic ammonium oxidation, the indexes of COD, ammonia nitrogen and total nitrogen in the wastewater of the chemical enterprise far exceeded the standard concentration limits. After the treatment by the method of the present invention, the indexes such as COD, ammonia nitrogen and total nitrogen in the wastewater decreased sharply and were all below the standard concentration limits, meeting the discharge requirements.

[0029] Application Example 2 Leachate from a Certain Domestic Waste Landfill

[0030] The wastewater is taken from the leachate of a domestic waste landfill. Since the concentration of refractory pollutants and COD in the leachate is relatively high, the anaerobic method is first used to decompose the refractory pollutants in the mixed wastewater, removing part of the COD and organic nitrogen. The anoxic prepositioned dual-shortcut coupled anaerobic ammonium oxidation process is used to treat the mixed wastewater. The specific process flow is shown in Figure 3 , and the content changes of pollutants in the mixed wastewater before and after treatment are shown in Table 2.

[0032] Table 2. Changes in pollutant content before and after treating landfill leachate by the anoxic prepositioned dual-shortcut coupled anaerobic ammonium oxidation process

[0033]

[0034] As can be seen from the above table, before applying the method of treating high-ammonia-nitrogen organic wastewater by the anoxic prepositioned dual-shortcut coupled anaerobic ammonium oxidation process, the indexes of COD, ammonia nitrogen, and total nitrogen in the landfill leachate far exceeded the standard concentration limits. After applying the method of the present invention, the indexes such as COD, ammonia nitrogen, and total nitrogen in the wastewater decreased sharply and were all below the standard concentration limits, meeting the discharge requirements.

[0035] The above has introduced in detail a method for treating high-ammonia-nitrogen wastewater by anoxic prepositioned dual-shortcut coupled anaerobic ammonium oxidation provided by the present invention, and elaborated on the principle and implementation method of the present invention with specific examples. The above examples are only used to help understand the present invention and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, several improvements and applications can also be made in the specific implementation manner and application scope, and all should be within the protection scope determined by the claims.

Claims

1. The technology of anoxic pre-double short-range coupling anaerobic ammonia oxidation for treating high-ammonia nitrogen organic wastewater is characterized by: It includes an anoxic zone, an anaerobic ammonium oxidation zone and a mud-water separation zone, and an internal reflow is arranged between the anaerobic ammonium oxidation zone and the anoxic zone.

2. The technical process according to claim 1, characterized in that The anoxic zone is placed at the front end of the anaerobic ammonium oxidation zone. The main functional bacteria in the anoxic zone are denitrifying bacteria and anaerobic ammonium oxidizing bacteria. The denitrifying bacteria use the nitrate nitrogen in the reflux liquid of the anaerobic ammonium oxidation zone as an electron acceptor and the remaining organic matter in the raw water as an electron donor to carry out short-range denitrification, converting nitrate nitrogen into nitrite nitrogen. At the same time, under the action of anaerobic ammonium oxidizing bacteria, nitrite nitrogen reacts with part of the ammonia nitrogen in the raw water to generate nitrogen gas.

3. The technical process according to claim 1, characterized in that The anaerobic ammonia oxidation zone is a mud film symbiotic system, which mainly includes biological fillers, aeration and reflow systems. The main functional bacteria are ammonia oxidizing bacteria and anaerobic ammonia oxidizing bacteria. Ammonia oxidizing bacteria will short-term nitrify part of the ammonia nitrogen and convert it into nitrite nitrogen. Under the further action of anaerobic ammonia oxidizing bacteria, the remaining ammonia nitrogen and nitrite nitrogen react to produce nitrogen gas.

4. The technical process according to claim 2, characterized in that The anoxic zone has a multifunctional effect. It can fully utilize the organic carbon source in the wastewater and reduce the impact of organic matter on the back-end anaerobic ammonium oxidation. At the same time, it can also serve as a safety buffer zone for back-end anaerobic ammonium oxidation to cope with fluctuating water quality and improve the overall stability of the system.

5. The technical process according to claim 3, characterized in that The biological filler is a fixed biological filler; the reflux system returns the nitrate nitrogen generated by the anaerobic ammonium oxidation process to the front-end anoxic section through a small proportion of internal reflux for deep denitrification; the aeration system is a trace aeration, and its main function is to provide oxygen and stirring for short-range nitrification.

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