Reclaimed water reuse treatment system for removing ammonia nitrogen

Abstract

The utility model discloses a reclaimed water reuse treatment system for removing ammonia nitrogen, which belongs to the technical field of sewage treatment and sequentially comprises a regulating tank, an anoxic tank, a biological contact oxidation tank, an MBR (membrane bioreactor) membrane tank and a reclaimed water reuse tank according to the water inlet direction of sewage treatment, the adjusting tank comprises a lifting pump, the anoxic tank is provided with a carbon source supplementing system, the biological contact oxidation tank comprises an alkalinity supplementing system and a water inlet pump, the carbon source supplementing system is linked with the lifting pump, the alkalinity supplementing system is linked with the water inlet pump, and the carbon source supplementing system is additionally arranged to meet the requirement of denitrifying bacteria on a carbon source. The carbon source supplementing system is linked with the adjusting tank lifting pump, and automatic supplementing of the carbon source is achieved by setting the supplementing flow of the carbon source; the alkalinity supplementing system is additionally arranged to maintain the pH value of the wastewater in the nitrification stage, the alkalinity supplementing amount is reasonably adjusted according to the actual operation wastewater pH value condition, and the alkalinity supplementing system is linked with the water inlet pump to achieve automatic alkalinity supplementing.

Description

Technical Field

[0001] The utility model relates to the technical field of sewage treatment, in particular to a reclaimed water recycling treatment system for removing ammonia nitrogen. Background Art

[0002] The ammonia nitrogen in the water quality of the original biochemical system for treating wastewater is very high, and the ammonia nitrogen concentration is basically maintained at 100-120mg / l, while COD is generally 300-400mg / l. The basic principle of biological denitrification of wastewater is to first oxidize ammonia nitrogen to nitrate through biological nitrification reaction, and then reduce nitrate to nitrogen gas through biological denitrification reaction, which escapes from the wastewater. Nitrifying bacteria are autotrophic microorganisms that use inorganic carbon compounds as carbon sources to obtain energy in the oxidation reaction. A large amount of protons (H+) are produced during the nitrification process. In order for the reaction to proceed smoothly, a large amount of alkali is required for neutralization. Theoretically, about 7.14g of alkalinity (calculated as calcium carbonate) is required for each 1g of ammonia nitrogen (calculated as N) oxidized. The water quality standard of urban miscellaneous water is relatively high, and the wastewater must be disinfected after treatment before it can be reused. The transformation should first consider the stable compliance of the effluent and try to reduce investment and make rational use of existing facilities.

[0003] Prior art, such as Chinese patent publication number CN204939215U, discloses a treatment system for removing total nitrogen from sewage, including a regulating tank, an anoxic tank, an aerobic tank and a sedimentation tank, wherein the water outlet of the regulating tank is connected to the water inlet of the anoxic tank via a conveying pipe, the water outlet of the anoxic tank is connected to the water inlet of the aerobic tank via a pipe, the water outlet of the aerobic tank is connected to the water inlet of the sedimentation tank via a pipe, the water outlet of the sedimentation tank is connected to a discharge trough, and the mud outlet of the sedimentation tank is connected to a sludge tank, characterized in that: the treatment system also includes a first reflux conveying pipeline and a second reflux conveying pipeline, one end of the first reflux conveying pipeline extends into the sludge layer of the sedimentation tank, and the other end is respectively connected to the anoxic tank and the aerobic tank; one end of the second reflux conveying pipeline is connected to the water outlet of the aerobic tank, and the other end is connected to the anoxic tank.

[0004] The above-mentioned sewage treatment system occupies a large space, has a sedimentation tank, and the treatment effect is not ideal, and the enrichment and recovery of other element resources at low pollutant concentrations in urban sewage is not achieved. Utility Model Content

[0005] The utility model provides a reclaimed water recycling treatment system for removing ammonia nitrogen, which occupies a small space and has a good ammonia nitrogen removal effect.

[0006] To achieve this purpose, the utility model adopts the following technical solutions:

[0007] A reclaimed water reuse treatment system for removing ammonia nitrogen comprises, in order according to the water inlet direction of sewage treatment, a regulating tank, an anoxic tank, a biological contact oxidation tank, an MBR membrane tank and a reclaimed water reuse tank; the regulating tank comprises a lifting pump, the anoxic tank is provided with a carbon source supplement system, the biological contact oxidation tank comprises an alkalinity supplement system and an inlet pump, the carbon source supplement system is linked to the lifting pump, and the alkalinity supplement system is linked to the inlet pump.

[0008] The preferred technical solution of the utility model is that the MBR membrane pool comprises a PVDF composite membrane, a membrane frame and an aeration system, and the filtration pore size of the PVDF composite membrane is between 0.3-0.5 μm.

[0009] The preferred technical solution of the utility model is that the PVDF composite membrane is configured as a PVDF composite hollow fiber curtain membrane.

[0010] The preferred technical solution of the utility model is that an activated carbon filtration system is connected between the MBR membrane pool and the reclaimed water reuse pool, and the activated carbon filtration system includes a carbon filter tank and a first backwash pump, and the first backwash pump is respectively connected to the regulating tank and the carbon filter tank.

[0011] The preferred technical solution of the utility model is that an ultrafiltration system is connected between the reclaimed water reuse tank and the activated carbon filtration system, the ultrafiltration system includes a second backwash pump and an ultrafiltration membrane, and the second backwash pump is respectively connected to the regulating tank and the ultrafiltration system.

[0012] An optimal technical solution of the utility model is that a disinfection tank is connected between the reclaimed water reuse tank and the ultrafiltration system, and the disinfection tank is provided with a pipeline mixer and a dosing system for adding disinfectants.

[0013] An optimal technical solution of the utility model is that a liquid level sensor and a pipeline pressure sensor are arranged in the reclaimed water reuse pool.

[0014] The preferred technical solution of the utility model is that it also includes a transition water tank, which is connected between the MBR membrane pool and the activated carbon filtration system, and the transition water tank is provided with a booster pump and a liquid level sensor.

[0015] An optimal technical solution of the utility model is that it also includes a lifting well, which is connected between the regulating tank and the sewage inlet, and a lifting pump is arranged in the lifting well.

[0016] A preferred technical solution of the utility model is that the disinfection pool includes sodium hypochlorite.

[0017] The beneficial effects of the utility model are:

[0018] (1) A carbon source supplement system is added during the anoxic stage to meet the carbon source demand of denitrifying bacteria. The carbon source supplement system is linked to the lifting pump of the regulating tank. By setting the carbon source supplement flow rate, the carbon source can be automatically added. An alkalinity supplement system is added during the aerobic stage to maintain the pH value of the wastewater during the nitrification stage. The alkalinity supplement amount is reasonably adjusted according to the actual pH value of the wastewater and linked to the water inlet pump to achieve automatic alkalinity addition.

[0019] (2) The high sludge concentration formed in the MBR membrane pool provides conditions for removing organic matter and converting ammonia nitrogen. Pollutants in the MBR membrane pool are harmlessly treated, and the MBR membrane effluent is very stable.

[0020] (3) The new reinforced PVDF composite hollow fiber membrane has stable performance, is not prone to wire breakage, is easy to operate and has a long service life.

[0021] (4) At the same time, due to the use of MBR membrane, the sedimentation tank of traditional treatment is eliminated, which saves land and investment, and the effluent is more stable. The high concentration of sludge required in the MBR membrane pool also reduces the sludge in the system. The above characteristics of MBR membrane also make the MBR membrane biological method greatly reduce the floor space of the sewage station. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the process of a reclaimed water reuse treatment system for removing ammonia nitrogen provided in a specific embodiment of the utility model;

[0023] Figure 2 It is an overall schematic diagram of a reclaimed water reuse treatment system for removing ammonia nitrogen provided in a specific embodiment of the utility model;

[0024] In the figure:

[0025] 1. Equalization tank; 2. Anoxic tank; 3. Biological contact oxidation tank; 4. MBR membrane tank; 5. Recycled water reuse tank; 6. Carbon filter tank; 7. First backwash pump; 8. Second backwash pump; 9. Ultrafiltration system; 10. Disinfection tank; 11. Transition water tank; 12. Lifting well. DETAILED DESCRIPTION

[0026] The technical solution of the utility model is further explained below with reference to the accompanying drawings and through specific implementation methods.

[0027] like Figure 1-2 As shown, the utility model provides a reclaimed water reuse treatment system for removing ammonia nitrogen, which is provided with a lifting well 12, a regulating tank 1, an anoxic tank 2, a biological contact oxidation tank 3, an MBR membrane tank 4, a transition water tank 11, an activated carbon filtration system, an ultrafiltration system 9, a disinfection tank 10 and a reclaimed water reuse tank in sequence according to the inlet direction of sewage.

[0028] The biological contact oxidation tank 3 and the anoxic tank 2 are respectively connected to an alkalinity supplement system and a carbon source supplement system.

[0029] In order to better filter and remove ammonia nitrogen, a first backwash pump 7 and a second backwash pump 8 are also included, which are respectively connected to the activated carbon filtration system and the ultrafiltration system 9 to facilitate backwashing of the sewage after passing through the MBR membrane pool 4.

[0030] In order to ensure the smooth biological denitrification of ammonia nitrogen, the biological denitrification must consider the effectiveness of the biological nitrification and denitrification process of ammonia nitrogen. Therefore, a carbon source supplement system is added in the anoxic tank 2 stage to meet the demand of denitrifying bacteria for carbon sources. The carbon source supplement system is linked with the lifting pump of the regulating tank 1. By setting the supplementary flow of the carbon source, the automatic addition of the carbon source is realized; an alkalinity supplement system is added in the biological contact oxidation tank stage to maintain the pH value of the wastewater in the nitrification stage. The alkalinity supplement amount is reasonably adjusted according to the actual operating wastewater pH value and linked with the water inlet pump to realize automatic addition of alkalinity.

[0031] After being treated in the biological contact oxidation pool 3, the effluent flows into the MBR membrane pool 4 by gravity. The MBR membrane pool 4 adopts an enhanced PVDF composite membrane, which can well meet the treatment requirements. The enhanced PVDF composite membrane system is composed of hollow fiber curtain membrane components, membrane racks and accessories, and an aeration system. The membrane filtration pore size is 0.4μm, and the pollutants are basically intercepted. The high sludge concentration formed in the MBR membrane pool 4 provides conditions for removing organic matter and converting ammonia nitrogen. The pollutants in the MBR membrane pool 4 are harmlessly treated. At the same time, the MBR membrane effluent is very stable. At the same time, a new type of enhanced PVDF composite hollow fiber membrane is adopted, which has stable performance, is not easy to break, is easy to operate, and has a long service life. At the same time, due to the use of the MBR membrane, the sedimentation tank of the traditional treatment is exempted, which saves land and investment, and the effluent is more stable. The high concentration of sludge required in the MBR membrane pool 4 also reduces the sludge in the system. The above characteristics of the MBR membrane also make the MBR membrane biological method greatly reduce the floor space of the sewage station.

[0032] Features of enhanced PVDF composite membrane:

[0033] 1. Ultra-high strength

[0034] The enhanced polyvinylidene fluoride hollow fiber is used in ultrafiltration membrane components. Due to the unique support layer membrane making technology, the tensile strength and compressive strength of the enhanced polyvinylidene fluoride hollow fiber are much higher than those of ordinary hollow fiber membranes. The tensile force is greater than 50KG, and it is vividly called "unbreakable membrane". In addition, due to the addition of special nanomaterials and modifiers, the defect of easy shedding of the membrane skin in practical applications has been better overcome.

[0035] 2. Good anti-pollution performance

[0036] The enhanced polyvinylidene fluoride hollow fiber membrane uses PVDF alloy membrane as its filtration layer. Its ultra-smooth membrane surface characteristics and unique charge properties make it have super anti-pollution performance.

[0037] 3. Good antioxidant properties

[0038] The chemical stability of the polyvinylidene fluoride (PVDF) material used in the polyvinylidene fluoride (PVDF) alloy hollow fiber membrane is far superior to that of polysulfone (PS), polyethersulfone (PES) and polyvinyl chloride (PVC) and other membrane materials, especially its ability to withstand oxidant cleaning is stronger. Oxidant cleaning is the main means to solve the problem of organic fouling and membrane clogging, so the membrane has a longer life and more stable flux.

[0039] 4. Ultra-large throughput

[0040] The enhanced polyvinylidene fluoride hollow fiber curtain membrane module adopts relatively independent special support layer technology and PVDF alloy membrane filtration layer technology. Its filtration layer is composed of a single-skin structure on the outer surface. The water passage resistance is significantly smaller than that of a double-skin ordinary membrane, and its structure with a higher porosity rate gives it ultra-large flux performance.

[0041] 5. Good interception performance

[0042] The enhanced polyvinylidene fluoride hollow fiber membrane uses PVDF alloy membrane as its filtration layer, with uniform pore size distribution and composed of a special dense cortical structure on the surface layer, which gives it excellent retention performance.

[0043] 6. Cleaning flux recovery is good

[0044] The enhanced polyvinylidene fluoride hollow fiber membrane uses PVDF alloy membrane as its filtration layer. Its special inner and outer dense double-skin structure allows pollutants to only stay on the outer surface of the membrane and not enter the mesh pores of the membrane. Therefore, it is very easy to clean and has good cleaning flux recovery.

[0045] The effluent from the MBR membrane enters the transition water tank 11, and is pumped into the activated carbon filtration system by a water production booster pump. The carbon filter tank 6 is used as a water quality assurance process. When the inlet water quality fluctuates and the effluent from the biochemical treatment system does not meet the inlet water quality of the ultrafiltration system 9, the valve is switched to allow the wastewater to pass through the carbon filter tank 6, and the porous activated carbon is used to absorb the dissolved pollutants in the wastewater.

[0046] The wastewater then enters the ultrafiltration system 9. The separation mechanism of ultrafiltration is mainly the "mechanical screening" mechanism, that is, the raw water containing "impurities" flows through the surface of the ultrafiltration membrane under the action of pressure as the driving force. Substances in the raw water that are larger than the pore size of the membrane are retained, and substances that are smaller than the pore size of the membrane pass through the membrane, thereby achieving the purpose of separation. The pore size range of the ultrafiltration membrane surface is approximately between 0.001 and 0.1 μm, and the molecular weight cutoff (MWCO) is approximately between 1000 and 500,000 Daltons. The ultrafiltration membrane has a high removal rate for suspended matter, colloids, bacteria and macromolecular substances in water, and has a partial removal rate for BOD, COD and small molecular substances in water, but can hardly retain small molecular substances such as water and soluble solids.

[0047] Benefits of Ultrafiltration System 9:

[0048] 1. There is no phase change during the separation process and the energy consumption is low.

[0049] 2. The separation process can be carried out at room temperature, which is suitable for the concentration or purification of some heat-sensitive substances such as juice, biological preparations and certain medicines.

[0050] 3. The separation process has low operating pressure, simple equipment and process flow, and is easy to operate, manage and maintain.

[0051] 4. Wide application range: ultrafiltration separation technology can be used for solutes with a molecular weight of 1000-500000 Dalton or a solute size of about 0.001-0.1μm. In addition, the use of a series of ultrafiltration membranes with different molecular weight cutoffs can be used to grade the molecular weight of each component in a mixture of solutes with different molecular weights.

[0052] Wastewater treated by the ultrafiltration system 9 needs to be disinfected in the disinfection tank 10 before it can be reused in the reclaimed water reuse tank 5. Sodium hypochlorite is used for disinfection, and a pipeline mixer is used to fully mix the wastewater and disinfectant to kill E. coli in the wastewater.

[0053] The treated wastewater enters the recycled water reuse tank 5, and the pipeline pressure sensor is used to control the automatic water supply. At the same time, a liquid level controller is set in the reuse water tank. When the liquid level in the reuse water tank is low, the water production pump starts to produce water, and when the liquid level in the reuse water tank is high, the water production stops, so as to achieve the same amount of water production as the amount of water used. An ultra-low liquid level protector is set in the reuse water tank. When the ultra-low liquid level appears in the reuse water tank, the constant pressure water supply pump stops running. A liquid level protector is set in the transition water tank 11. When the ultra-low liquid level appears in the transition water tank 11, the water production pump stops working. At the same time, when the transition water tank 11 is super-high, it flows to the discharge port through the overflow pipe, so that the excess MBR produced water meets the discharge standards.

[0054] The above process can be realized through a control system and belongs to the scope of existing technology.

[0055] In order to better realize the aforementioned ammonia nitrogen removal process, the MBR membrane pool 4 includes an enhanced polyvinylidene fluoride (PVDF) hollow fiber membrane, an MBR membrane frame, an MBR membrane connector, an MBR membrane self-priming pump, a blower, a liquid level controller, a flow meter and an aeration system. The activated carbon filtration system includes a carbon filter tank 6, a coconut shell activated carbon filter material and a multi-way valve. The ultrafiltration system 9 includes a raw water pump, an ultrafiltration membrane, a second backwash pump 8, a cleaning system, an automatic control valve, etc. The reclaimed water reuse pool 5 includes a PE water tank, a constant pressure water supply pump and a liquid level controller.

[0056] The present invention is described by preferred embodiments, and those skilled in the art will appreciate that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. The present invention is not limited to the specific embodiments disclosed herein, and other embodiments falling within the claims of this application are within the scope of protection of the present invention.

Claims

1. A reclaimed water recycling treatment system for removing ammonia nitrogen, characterized in that: According to the water inlet direction of the sewage treatment, the sewage treatment system includes a regulating tank (1), an anoxic tank (2), a biological contact oxidation tank (3), an MBR membrane tank (4) and a reclaimed water reuse tank (5); The regulating tank (1) includes a lifting pump, the anoxic tank (2) is provided with a carbon source supplement system, and the biological contact oxidation tank (3) includes an alkalinity supplement system and a water inlet pump, the carbon source supplement system is linked to the lifting pump, and the alkalinity supplement system is linked to the water inlet pump.

2. The reclaimed water reuse treatment system for removing ammonia nitrogen according to claim 1 is characterized in that: The MBR membrane pool (4) comprises a PVDF composite membrane, a membrane frame and an aeration system, and the filtration pore size of the PVDF composite membrane is between 0.3 and 0.5 μm.

3. The reclaimed water reuse treatment system for removing ammonia nitrogen according to claim 2 is characterized in that: The PVDF composite membrane is configured as a PVDF composite hollow fiber curtain membrane.

4. The reclaimed water reuse treatment system for removing ammonia nitrogen according to claim 1 is characterized in that: An activated carbon filtration system is connected between the MBR membrane pool (4) and the reclaimed water reuse pool (5), and the activated carbon filtration system comprises a carbon filter tank (6) and a first backwash pump (7), and the first backwash pump (7) is respectively connected to the regulating pool (1) and the carbon filter tank (6).

5. The reclaimed water reuse treatment system for removing ammonia nitrogen according to claim 4 is characterized in that: An ultrafiltration system (9) is connected between the reclaimed water reuse tank (5) and the activated carbon filtration system. The ultrafiltration system (9) comprises a second backwash pump (8) and an ultrafiltration membrane. The second backwash pump (8) is connected to the regulating tank (1) and the ultrafiltration system (9), respectively.

6. The reclaimed water reuse treatment system for removing ammonia nitrogen according to claim 5 is characterized in that: A disinfection tank (10) is connected between the reclaimed water reuse tank (5) and the ultrafiltration system (9), and the disinfection tank (10) is provided with a pipeline mixer and a dosing system for adding disinfectants.

7. The reclaimed water reuse treatment system for removing ammonia nitrogen according to claim 3 is characterized in that: A liquid level sensor and a pipeline pressure sensor are arranged in the reclaimed water reuse pool (5).

8. The reclaimed water reuse treatment system for removing ammonia nitrogen according to claim 4 is characterized in that: It also comprises a transition water tank (11), wherein the transition water tank (11) is connected between the MBR membrane pool (4) and the activated carbon filtration system, and the transition water tank (11) is provided with a booster pump and a liquid level sensor.

9. The reclaimed water reuse treatment system for removing ammonia nitrogen according to claim 1, characterized in that: It also comprises a lifting well (12), wherein the lifting well (12) is connected between the regulating tank (1) and the sewage inlet, and a lifting pump is arranged in the lifting well (12).

10. The reclaimed water reuse treatment system for removing ammonia nitrogen according to claim 6, characterized in that: The disinfection pool (10) contains sodium hypochlorite.

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