Treatment equipment and process applied to chemical high-nitrogen-content wastewater

Abstract

The invention discloses treatment equipment and process applied to chemical high-nitrogen-content wastewater, the treatment equipment comprises a pretreatment system, a chemical treatment system is arranged on one side of the pretreatment system, and a deep treatment system is arranged on the front side of a biological treatment system. According to the method, a biological treatment technology and a chemical oxidation technology are combined, and most biodegradable organic matters are removed in the early stage by utilizing the efficient degradation capability of the biological treatment technology; for wastewater simultaneously containing high-concentration and refractory organic substances, the biodegradability of the wastewater is improved, the organic substances are eliminated, the COD (Chemical Oxygen Demand) concentration is reduced, competition with biological denitrification obligate bacteria is avoided, and the normal denitrification reaction process is inhibited through an efficient anaerobic means assisted by technologies such as chemical oxidation and the like. For wastewater with relatively high ammonia nitrogen concentration, the biochemical combination method not only can realize the ammonia nitrogen removal rate up to 98%, but also can obviously reduce the COD (Chemical Oxygen Demand) concentration in the wastewater, thereby achieving the targets of efficient deamination and pollution emission reduction.

Description

Technical Field

[0001] The invention relates to the technical field of chemical high-nitrogen wastewater treatment, and in particular to a treatment device and process for chemical high-nitrogen wastewater. Background Art

[0002] Chemical high-nitrogen wastewater is a type of industrial wastewater containing high-concentration nitrogen compounds, which mainly comes from various reactions, washing, flushing and other links in the chemical production process. This type of wastewater usually has the characteristics of complex composition, high pollutant concentration, high toxicity, poor biodegradability, etc., posing a serious threat to the environment and ecosystem. Therefore, the development of efficient and stable treatment equipment and processes is crucial for the treatment of chemical high-nitrogen wastewater.

[0003] Existing biological denitrification is mainly divided into two categories according to different transformation pathways and receptors, one is nitrification and denitrification technology, and the other is anaerobic ammonia oxidation technology. Conventional biological denitrification methods are mainly nitrification-denitrification combined treatment technologies. Examples of this technology include A / O process, A2 / O process, UCT process, VIP process, oxidation ditch process, Carrousel process, Bardenpho process, SBR process, biological multiplication process or aerobic (facultative) biological ponds, etc. Therefore, biological denitrification methods are widely used. Biological nitrification is relatively cheap and easy to operate, but it occupies a large area.

[0004] For example, a coal chemical wastewater treatment process disclosed in the announcement number CN112321074A, the device in this patent mainly uses a primary A / O+ sedimentation tank and a secondary A / O+ sedimentation tank to treat the wastewater, while in the traditional nitrification and denitrification process, the nitrification process mainly relies on oxygen as an electron acceptor to oxidize ammonia nitrogen into nitrate. This process requires a large amount of oxygen supply, which not only increases energy consumption and operating costs, but also when treating high ammonia nitrogen wastewater, the demand for oxygen increases exponentially. At the same time, the traditional nitrification and denitrification process will also produce a large amount of residual sludge, which further increases the treatment cost and environmental pollution risk. However, in the current industrial environment, the technical requirements for chemical wastewater treatment are also constantly improving.

[0005] Therefore, it is necessary to invent a treatment device and process for chemical high nitrogen wastewater to solve the above problems. Summary of the invention

[0006] The purpose of the present invention is to provide a treatment device and process for chemical high-nitrogen wastewater, so as to solve the problem that when treating high-ammonia nitrogen wastewater, the demand for oxygen increases exponentially, which not only increases energy consumption and operating costs, but also further increases treatment costs and environmental pollution.

[0007] In order to achieve the above-mentioned purpose, the present invention provides the following technical solutions: a treatment device and process for chemical high-nitrogen wastewater, comprising a pretreatment system, a chemical treatment system, a biological treatment system and a deep treatment system, wherein a chemical treatment system is arranged on one side of the pretreatment system, a biological treatment system is arranged on one side of the chemical treatment system, and a deep treatment system is arranged on the front side of the biological treatment system.

[0008] Preferably, the pretreatment system includes a coarse / fine screen, a regulating tank and a coagulation sedimentation tank, which further improves the removal of solid impurities in the wastewater.

[0009] Preferably, the front end of the pretreatment system is a coarse screen, and the fine screen is located behind the coarse screen, the regulating tank is located behind the fine screen, and the coagulation sedimentation tank is located after the regulating tank, which is the last step of the pretreatment system, realizing the gradual removal of solid impurities inside the wastewater.

[0010] Preferably, the chemical treatment system adopts the breakpoint chlorination method, which is a chemical denitrification process in which chlorine gas or sodium hypochlorite is introduced into the wastewater to oxidize NH3-N in the wastewater into N2.

[0011] Preferably, the biological treatment system includes a variety of nitrogen removal processes, specifically direct nitrite denitrification, a combination of short-range nitrification and anaerobic ammonium oxidation, and membrane bioreactor (MBR) technology. The anaerobic ammonium oxidation reaction refers to the reaction in which nitrite nitrogen replaces oxygen as an electron acceptor to oxidize ammonia nitrogen into nitrogen gas.

[0012] Preferably, the anaerobic ammonium oxidation step in the biological treatment system adopts an anaerobic ammonium oxidation reactor, and an anaerobic ammonium oxidation bacterial community is arranged in the anaerobic ammonium oxidation reactor, and a real-time monitoring and control system is also provided in the anaerobic ammonium oxidation reactor for real-time monitoring of pH value, free ammonia concentration, dissolved oxygen concentration and NH4+ load, etc., so as to achieve the purpose of denitrification.

[0013] Preferably, the membrane bioreactor (MBR) in the biological treatment system forms multifunctional zones, which are specifically anaerobic zone, facultative anaerobic zone and aerobic zone, so that high ammonia nitrogen wastewater can be treated more thoroughly and efficiently.

[0014] Preferably, the deep treatment system includes a sand filter and activated carbon adsorption tank and a disinfection tank. The sand filter and activated carbon adsorption tank further purify the water quality, while the disinfection tank uses ultraviolet disinfection to kill pathogenic microorganisms, bacteria, etc. in the wastewater to ensure that the effluent meets the discharge standard or reuse water quality requirements.

[0015] Preferably, the method comprises the following steps:

[0016] S1: The wastewater first enters the pretreatment system, where it passes through a coarse screen to remove large solid particles and floating objects. Then, it enters a fine screen to further remove fine particles and suspended matter. Then, the wastewater flows into a regulating tank to balance the fluctuations in water quality and quantity. Finally, the wastewater passes through a coagulation sedimentation tank, where coagulants are added to aggregate suspended matter, colloids, etc. into larger particles and settle to the bottom. The purified wastewater enters the next stage.

[0017] S2: The pretreated wastewater enters the chemical treatment system and is treated by the breakpoint chlorination method. By adding an appropriate amount of chlorine or sodium hypochlorite and other oxidants, the ammonia nitrogen in the wastewater is oxidized into nitrogen or other harmless substances, while removing some organic matter and color;

[0018] S3: The wastewater after chemical treatment enters the biological treatment system. First, the wastewater is subjected to the direct nitrite denitrification process to convert part of the ammonia nitrogen into nitrite, and then further into nitrogen gas. Then, the wastewater enters the short-range nitrification and anaerobic ammonium oxidation combined process, using specific microorganisms to convert the remaining ammonia nitrogen into nitrogen gas, achieving efficient nitrogen removal. Finally, the membrane bioreactor (MBR) can further remove organic matter, suspended solids and microorganisms in the wastewater to improve the effluent quality.

[0019] S4: The wastewater after biological treatment enters the deep treatment system. The wastewater first passes through sand filtration and activated carbon adsorption tanks to remove impurities such as suspended solids, organic matter and odor. Finally, the wastewater enters the disinfection tank and kills pathogenic microorganisms in the water by adding disinfectants to ensure that the effluent meets the discharge standards or reuse water quality requirements.

[0020] In the above technical solution, the technical effects and advantages provided by the present invention are:

[0021] 1. The present invention combines biological treatment technology with chemical oxidation technology, and utilizes the efficient degradation capacity of biological treatment technology to remove most of the biodegradable organic matter in the early stage; for wastewater containing high-concentration, difficult-to-degrade organic matter at the same time, it will use efficient anaerobic means and chemical oxidation and other technologies to first improve the biodegradability of wastewater, eliminate organic matter, reduce COD concentration, avoid competition with biological denitrification bacteria, and inhibit the normal reaction process of denitrification. For wastewater with high ammonia nitrogen concentration, the use of biochemical combined method can not only achieve an ammonia nitrogen removal rate of up to 98%, but also significantly reduce the COD concentration in the wastewater, achieving the goal of efficient denitrification and pollution reduction;

[0022] 2. The present invention combines short-range nitrification and anaerobic ammonium oxidation. Short-range nitrification is to oxidize ammonia nitrogen to nitrite nitrogen, and then directly reduce nitrite nitrogen to chlorine. Compared with traditional nitrification / denitrification, short-range nitrification can save 25% of oxygen demand and 40% of carbon source (calculated as methane), while anaerobic ammonium oxidation refers to the reaction in which nitrite nitrogen replaces oxygen as an electron acceptor to oxidize ammonia nitrogen to nitrogen. Compared with the traditional nitrification / denitrification process, the oxygen demand and organic carbon demand of anaerobic ammonium oxidation reaction are lower, and it is suitable for treating wastewater with low BOD5 / COD and low COD / N;

[0023] 3. The present invention adopts efficient ammonia oxidizing bacteria for biological denitrification, optimizes the inoculation and culture conditions of denitrifying bacteria, improves the adaptability and stability of wastewater environment to biological denitrification; develops a technology combining membrane bioreactor (MBR), anaerobic ammonia oxidation, short-range nitrification and denitrification, etc., overcomes the shortcomings of a single biological treatment process, and realizes efficient removal of ammonia nitrogen and organic matter in wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0025] Figure 2 It is a schematic diagram of the overall front structure of the present invention;

[0026] Figure 3 The three-dimensional structure diagram of the sand filter and activated carbon adsorption tank and disinfection tank of the present invention is shown in FIG.

[0027] Figure 4 Schematic diagram of the wastewater treatment process of the present invention.

[0028] Description of reference numerals:

[0029] 1. Pretreatment system; 2. Chemical treatment system; 3. Biological treatment system; 4. Deep treatment system; 401. Sand filter and activated carbon adsorption tank; 402. Disinfection tank. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0031] The present invention provides Figure 1-4The treatment equipment and process shown in the figure are applied to the treatment of high-nitrogen-containing chemical wastewater, including a pretreatment system 1, a chemical treatment system 2, a biological treatment system 3 and a deep treatment system 4. The chemical treatment system 2 is arranged on one side of the pretreatment system 1, the biological treatment system 3 is arranged on one side of the chemical treatment system 2, and the deep treatment system 4 is arranged on the front side of the biological treatment system 3. The pretreatment system 1 includes a coarse / fine grid, a regulating tank and a coagulation sedimentation tank. The front end of the pretreatment system 1 is the coarse grid, and the fine grid is located behind the coarse grid, the regulating tank is located behind the fine grid, and the coagulation sedimentation tank is located after the regulating tank, which is the last step of the pretreatment system 1. The deep treatment system 4 includes a sand filter and activated carbon adsorption tank 401 and a disinfection tank 402.

[0032] Through the organic combination of pretreatment system 1, chemical treatment system 2, biological treatment system 3 and deep treatment system 4, comprehensive and efficient treatment of chemical high-nitrogen wastewater is achieved. The synergistic effect of each system and its components ensures that the effluent quality meets the discharge standards, while reducing treatment costs and environmental impact.

[0033] The chemical treatment system 2 adopts the breakpoint chlorination method, and the biological treatment system 3 includes a variety of nitrogen removal processes, specifically direct nitrite denitrification (nitritation / denitrification), a combination of short-term nitrification and anaerobic ammonium oxidation (full-process autotrophic denitrification), and membrane bioreactor (MBR) technology. The anaerobic ammonium oxidation step in the biological treatment system 3 adopts an anaerobic ammonium oxidation reactor, and an anaerobic ammonium oxidation bacterial community is arranged in the anaerobic ammonium oxidation reactor, and a real-time monitoring and control system is also provided in the anaerobic ammonium oxidation reactor for real-time monitoring of pH value, free ammonia concentration, dissolved oxygen concentration and NH4+ load, etc. The membrane bioreactor (MBR) in the biological treatment system 3 forms multifunctional areas, which are specifically anaerobic zone, facultative anaerobic zone and aerobic zone.

[0034] The chemical treatment system 2 adopts the breakpoint chlorination method, which mainly adds excess chlorine or sodium hypochlorite to the wastewater to make the ammonia nitrogen (NH3-N) in the wastewater react with chlorine to generate nitrogen (N2). By precisely controlling the amount of chlorine added, the ammonia nitrogen in the wastewater is completely oxidized into nitrogen at the "breakpoint", thereby achieving the removal of ammonia nitrogen. The biological treatment system 3 achieves efficient nitrogen removal through the combination of multiple nitrogen removal processes. Among them, the combined process of direct nitrite denitrification, short-range nitrification and anaerobic ammonia oxidation can significantly reduce energy consumption and carbon source consumption. The membrane bioreactor (MBR) technology improves the wastewater treatment efficiency and effluent water quality, which not only significantly reduces the energy consumption and carbon source consumption in the wastewater treatment process, but also improves the nitrogen removal efficiency and effect.

[0035] The following steps are involved:

[0036] Step 1: The wastewater first enters the pretreatment system 1, where it passes through a coarse screen to remove large solid particles and floating objects. Then, the wastewater enters a fine screen to further remove fine particles and suspended matter. Then, the wastewater flows into a regulating tank to balance the fluctuations in water quality and water volume. Finally, the wastewater passes through a coagulation sedimentation tank, where coagulants are added to aggregate suspended matter, colloids, etc. into larger particles and settle to the bottom. The purified wastewater enters the next stage;

[0037] Step 2: The pretreated wastewater enters the chemical treatment system 2, where the wastewater is treated by the breakpoint chlorination method. By adding an appropriate amount of chlorine or sodium hypochlorite and other oxidants, the ammonia nitrogen in the wastewater is oxidized into nitrogen or other harmless substances, while removing some organic matter and color;

[0038] Step 3: The chemically treated wastewater enters the biological treatment system 3. First, the wastewater is subjected to the nitrite direct denitrification (nitrification / denitrification) process to convert part of the ammonia nitrogen into nitrite, and then further into nitrogen gas. Then, the wastewater enters the short-range nitrification and anaerobic ammonia oxidation combined (full autotrophic denitrification) process, and uses specific microorganisms to convert the remaining ammonia nitrogen into nitrogen gas to achieve efficient nitrogen removal. Finally, the membrane bioreactor (MBR) can further remove organic matter, suspended solids and microorganisms in the wastewater to improve the effluent quality.

[0039] Step 4: The wastewater after biological treatment enters the deep treatment system 4. The wastewater first passes through the sand filter and activated carbon adsorption tank 401 to remove impurities such as suspended matter, organic matter and odor. Finally, the wastewater enters the disinfection tank 402, and pathogenic microorganisms in the water are killed by adding disinfectants (such as chlorine, ozone, etc.) to ensure that the effluent meets the discharge standard or reuse water quality requirements.

[0040] Working principle of the present invention:

[0041] Refer to the instruction manual Figure 1-4 When using the present invention, first, the wastewater enters the coarse grid and fine grid of the pretreatment system 1 to remove particulate matter and suspended matter, then the wastewater flows into the regulating tank, in which the water quality and water volume fluctuations of the wastewater are balanced, and finally, the wastewater enters the coagulation sedimentation tank, in which the suspended matter, colloid, etc. in the wastewater are aggregated into larger particles and precipitated to the bottom by adding a coagulant, and the supernatant after precipitation is the purified wastewater, which enters the next stage of the chemical treatment system 2;

[0042] In the chemical treatment system 2, the breakpoint chlorination method is used to treat the wastewater. The wastewater after chemical treatment enters the biological treatment system 3. In the biological treatment system 3, the nitrite direct denitrification (nitrification / denitrification) process is respectively adopted, and the denitrifying bacteria are used to reduce the nitrite to nitrogen gas. Then, the wastewater enters the short-range nitrification and anaerobic ammonia oxidation combined (full autotrophic denitrification) process. In this process, specific microorganisms are used to convert the remaining ammonia nitrogen into nitrogen gas to achieve efficient removal of nitrogen. Finally, the wastewater enters the membrane bioreactor (MBR). The MBR can further remove organic matter, suspended matter and microorganisms in the wastewater and improve the effluent water quality. The wastewater after biological treatment enters the deep treatment system 4. In the deep treatment system 4, the wastewater first passes through the sand filter and the activated carbon adsorption tank 401, which can mainly remove suspended matter, organic matter, odor, etc. Finally, the wastewater enters the disinfection tank 402. In the disinfection tank 402, ultraviolet rays are used to kill pathogenic microorganisms in the water, so that the disinfected wastewater can meet the discharge standard or the reuse water quality requirements.

Claims

1. A treatment device and process for high nitrogen content wastewater in chemical industry, comprising a pretreatment system (1), a chemical treatment system (2), a biological treatment system (3) and a deep treatment system (4), characterized in that: A chemical treatment system (2) is arranged on one side of the pretreatment system (1), a biological treatment system (3) is arranged on one side of the chemical treatment system (2), and a deep treatment system (4) is arranged on the front side of the biological treatment system (3).

2. The treatment equipment and process for chemical high nitrogen wastewater according to claim 1, characterized in that: The pretreatment system (1) comprises a coarse / fine grid, a regulating tank and a coagulation sedimentation tank.

3. The treatment equipment and process for chemical high nitrogen wastewater according to claim 2, characterized in that: The front end of the pretreatment system (1) is a coarse screen, and the fine screen is located behind the coarse screen. The regulating tank is located behind the fine screen. The coagulation sedimentation tank is located after the regulating tank and is the last step of the pretreatment system (1).

4. The treatment equipment and process for chemical high nitrogen wastewater according to claim 1, characterized in that: The chemical treatment system (2) adopts the breakpoint chlorination method.

5. The treatment equipment and process for chemical high nitrogen wastewater according to claim 1, characterized in that: The biological treatment system (3) includes a variety of nitrogen removal processes, specifically direct nitrite denitrification (nitritation / denitrification), a combination of short-cut nitrification and anaerobic ammonium oxidation (full autotrophic denitrification), and membrane bioreactor (MBR) technology.

6. The treatment equipment and process for chemical high nitrogen wastewater according to claim 4, characterized in that: The anaerobic ammonium oxidation step in the biological treatment system (3) adopts an anaerobic ammonium oxidation reactor, and an anaerobic ammonium oxidation bacterial community is arranged in the anaerobic ammonium oxidation reactor. The anaerobic ammonium oxidation reactor is also provided with a real-time monitoring and control system for real-time monitoring of pH value, free ammonia concentration, dissolved oxygen concentration and NH4+ load, etc.

7. The treatment equipment and process for chemical high nitrogen wastewater according to claim 4, characterized in that: The membrane bioreactor (MBR) in the biological treatment system (3) forms multifunctional zones, which are specifically anaerobic zone, facultative anaerobic zone and aerobic zone.

8. The treatment equipment and process for chemical high nitrogen wastewater according to claim 1, characterized in that: The deep treatment system (4) comprises a sand filtration and activated carbon adsorption tank (401) and a disinfection tank (402).

9. The treatment equipment and process for chemical high nitrogen wastewater according to claims 1 to 8, characterized in that: The following steps are involved: S1: The wastewater first enters the pretreatment system (1), where it passes through a coarse screen to remove large solid particles and floating objects. Then, the wastewater enters a fine screen to further remove fine particles and suspended matter. Then, the wastewater flows into a regulating tank to balance the fluctuations in water quality and water volume. Finally, the wastewater passes through a coagulation sedimentation tank, where coagulants are added to aggregate suspended matter, colloids, etc. into larger particles and settle to the bottom. The purified wastewater enters the next stage. S2: The pretreated wastewater enters the chemical treatment system (2), where the wastewater is treated by the breakpoint chlorination method. By adding an appropriate amount of chlorine or sodium hypochlorite and other oxidants, the ammonia nitrogen in the wastewater is oxidized into nitrogen or other harmless substances, while removing some organic matter and color; S3: The chemically treated wastewater enters the biological treatment system (3). First, the wastewater is subjected to the nitrite direct denitrification (nitritation / denitrification) process to convert part of the ammonia nitrogen into nitrite, and then further into nitrogen gas. Then, the wastewater enters the short-cut nitrification and anaerobic ammonia oxidation combined (full autotrophic denitrification) process to use specific microorganisms to convert the remaining ammonia nitrogen into nitrogen gas, thus achieving efficient nitrogen removal. Finally, the membrane bioreactor (MBR) can further remove organic matter, suspended solids and microorganisms in the wastewater, thus improving the effluent quality. S4: The wastewater after biological treatment enters the deep treatment system (4), where it first passes through sand filtration and an activated carbon adsorption tank (401) to remove impurities such as suspended solids, organic matter and odor. Finally, the wastewater enters the disinfection tank (402), where disinfectants (such as chlorine, ozone, etc.) are added to kill pathogenic microorganisms in the water to ensure that the effluent meets the discharge standard or reuse water quality requirements.

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