Two-stage ozone biological fluidized bed water purification treatment system and process

Abstract

The invention belongs to the technical field of feed water treatment, and relates to a two-stage ozone biological fluidized bed water purification treatment system and process. The device sequentially comprises a first-stage ozone oxidation pond, a first-stage biological fluidized bed, a second-stage ozone oxidation pond and a second-stage biological fluidized bed according to the flowing direction of raw water, wherein the primary ozone oxidation pond comprises an outer pond body and an inner pond body, the outer pond body is closed, a water inlet and a water outlet are formed in the upper part of the outer pond body, a sludge collecting area is arranged at the bottom of the outer pond body, the inner pond body is suspended in the outer pond body, the top of the inner pond body is higher than the water outlet of the outer pond body, and a channel between the side wall of the outer pond body and the side wall of the inner pond body is set as a settling area; a first ozone aeration device is arranged at the lower part in the inner tank body; and the flowing direction of raw water in the primary ozone oxidation tank is an ozone oxidation zone, a settling zone and a water outlet in sequence. The invention aims to provide a two-stage ozone biological fluidized bed water purification treatment system and process. The water purification treatment system and process provided by the invention can deeply remove pollutants in raw water.

Description

Technical Field

[0001] The present invention belongs to the technical field of water treatment, and relates to a dual-stage ozone biological fluidized bed water purification treatment system and process. Background Art

[0002] Disclosing the information of this background art section is only intended to increase the understanding of the overall background of the present invention, and is not necessarily regarded as an admission or any form of implication that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] With the development of industrial and agricultural economy, the concentrations of refractory pollutants, ammonia nitrogen, and odor substances in surface water sources have increased year by year. Traditional water purification treatment processes such as coagulation, sedimentation, filtration, and disinfection have very limited removal effects on refractory organic matter, ammonia nitrogen, and odor substances, resulting in relatively high concentrations of pollutants remaining in the effluent of water purification plants. This not only affects the taste of drinking water but also poses potential hazards to human health. For example, some refractory organic matters have carcinogenic, teratogenic, and mutagenic effects, while odor substances such as geosmin (GSM) and 2-methylisoborneol (2-MIB) can cause peculiar smells in drinking water, reducing the public's acceptance of drinking water quality.

[0004] Currently, the commonly used advanced treatment processes mainly include ozone-hydrogen peroxide advanced oxidation process, ozone catalytic oxidation process, ozone biological activated carbon process, ozone biological fluidized bed process, etc. The above ozone-related processes all have good removal effects. However, in the face of increasingly complex source water quality, the operating costs of existing ozone series processes are constantly increasing, and the removal efficiency is limited and difficult to continue to improve. Moreover, by-products are easily generated, resulting in relatively high concentrations of refractory pollutants, ammonia nitrogen, odor substances, and by-products remaining in the effluent.

[0005] Therefore, for source water with relatively serious pollution, it is of great practical significance to develop a water purification treatment process that can efficiently remove pollutants such as refractory organic matter, ammonia nitrogen, turbidity, and odor substances. Summary of the Invention

[0006] In order to solve the problems of low removal efficiency of refractory organic matter, odor substances, and ammonia nitrogen in the existing water purification treatment process when treating polluted surface water sources, the purpose of the present invention is to provide a dual-stage ozone biological fluidized bed water purification treatment system and process, and the water purification treatment system and process provided by the present invention can achieve in-depth removal of pollutants in source water (raw water).

[0007] To achieve the above purpose, the present invention adopts the following technical solutions: In a first aspect, a two-stage ozone biological fluidized bed water purification treatment system is provided for being arranged at the front end of a conventional water purification treatment system (coagulation + sedimentation + filtration + disinfection) to pre-treat raw water. It sequentially includes a first-stage ozone oxidation tank, a first-stage biological fluidized bed, a second-stage ozone oxidation tank, and a second-stage biological fluidized bed according to the raw water flow direction. Among them, the first-stage ozone oxidation tank includes an outer tank body and an inner tank body. The outer tank body is enclosed, and an inlet and an outlet are provided at the upper part of the outer tank body. The inlet is connected to the inner tank body through a pipeline. A sludge collection area is arranged at the bottom of the outer tank body. The inner tank body is a cylindrical structure with both upper and lower ends open and is suspended in the outer tank body. The top of the inner tank body is higher than the water surface of the first-stage ozone oxidation tank. The channel between the side wall of the outer tank body and the side wall of the inner tank body is set as a sedimentation area, and a sedimentation structure is arranged in the sedimentation area. The inside of the inner tank body is an ozone oxidation area, and a first ozone aeration device is arranged at the lower part of the ozone oxidation area. The flow direction of the raw water in the first-stage ozone oxidation tank is sequentially the ozone oxidation area, the sedimentation area, and the outlet. Both the first-stage biological fluidized bed and the second-stage biological fluidized bed are enclosed, and a fluidized bed is arranged in both the first-stage biological fluidized bed and the second-stage biological fluidized bed. Packing and activated carbon are filled in the fluidized bed. The second-stage ozone oxidation tank is enclosed and a second ozone aeration device and a hydrogen peroxide dosing device are arranged inside. The first ozone aeration device and the second ozone aeration device are connected to an ozone source, and the hydrogen peroxide dosing device is connected to a hydrogen peroxide source.

[0008] Due to the continuous increase in the concentration of organic matter in some source waters, the organic matter wraps the inorganic particles in the water, reducing the hydrophilicity and increasing the hydrophobicity of the inorganic particles, presenting a suspended state in the water, and it is difficult to form flocs for sedimentation during the mixing and flocculation process. In the present invention, the inside of the inner tank body in the first-stage ozone oxidation tank is set as the ozone oxidation area. By introducing ozone, the organic matter on the surface of the inorganic particles is oxidized under the action of ozone oxidation, thereby restoring the hydrophilicity and flocculability of the inorganic particles, and then sedimenting through the sedimentation area to achieve the separation of particles and water. At the same time, the ozone oxidation area and the sedimentation area are separated by the inner tank body, which can prevent ozone bubbles from entering the sedimentation area and reduce the interference with the sedimentation process of the particles, facilitating the sedimentation separation of the particles in the sedimentation area.

[0009] In some embodiments, the sedimentation structure is a lamella and / or a lamella tube. This sedimentation structure has a high sedimentation load and can greatly improve the separation and removal efficiency of particles.

[0010] In some embodiments, the first-stage biological fluidized bed is a closed tank body structure, with an inlet arranged at the bottom and an outlet arranged at the upper part. Through the arrangement of the inlet and the outlet, the water flow direction is controlled, which is beneficial to maintaining the fluidized state of the packing in the fluidized bed.

[0011] In some embodiments, from bottom to top in the first-stage biological fluidized bed are a uniform water distribution zone, a supporting layer, and a fluidized layer. By providing the water distribution zone and the supporting layer, it not only serves to support the packing in the fluidized layer but also facilitates the uniform distribution of water. The fluidized layer is filled with porous packing, providing a carrier for the attachment and growth of microorganisms.

[0012] In some embodiments, in the second-stage ozone oxidation tank, a water inlet is provided at the upper part and a water outlet is provided at the bottom. By providing the water inlet and the water outlet, the water flow direction is controlled to form a gas-liquid countercurrent contact between ozone and water. With a high concentration gradient at the gas-liquid interface and a fast mass transfer rate, a relatively high dissolved ozone concentration can be maintained in the water, improving the utilization efficiency of ozone. The dissolved ozone in the water comes into sufficient contact with the dissolved organic matter in the water, facilitating the further advanced treatment of pollutants in the raw water.

[0013] In some embodiments, the second-stage biological fluidized bed is a closed tank structure, with a water inlet provided at the bottom and a water outlet provided at the upper part. By providing the water inlet and the water outlet, the water flow direction is controlled, which is beneficial to maintaining the fluidized state of the packing in the fluidized bed and advanced treating the pollutants in the raw water.

[0014] In some embodiments, from bottom to top in the second-stage biological fluidized bed are a uniform water distribution zone, a supporting layer, and a fluidized layer. By providing the water distribution zone and the supporting layer, it not only serves to support the packing in the fluidized layer but also facilitates the uniform distribution of water. The fluidized layer is filled with porous packing, providing a carrier for the attachment and growth of microorganisms.

[0015] In some embodiments, an ozone tail gas destructor is provided at the top of the first-stage ozone oxidation tank. It decomposes the unutilized ozone to prevent air pollution.

[0016] In some embodiments, an ozone tail gas destructor is provided at the top of the first-stage biological fluidized bed.

[0017] In some embodiments, an ozone tail gas destructor is provided at the top of the second-stage ozone oxidation tank. It decomposes the unutilized ozone to prevent air pollution.

[0018] In some embodiments, an ozone tail gas destructor is provided at the top of the second-stage biological fluidized bed.

[0019] In some embodiments, the activated carbon filled in the first-stage biological fluidized bed is coal-based activated carbon, and the activated carbon filled in the second-stage biological fluidized bed is coconut shell activated carbon. The source water first passes through the first-stage ozone oxidation tank, then enters the first-stage biological fluidized bed, then enters the second-stage ozone oxidation tank, and then enters the second-stage biological fluidized bed; after the source water is subjected to ozone oxidation and sedimentation separation of particulate matters, when entering the first-stage biological fluidized bed, the naturally occurring microorganisms in the source water adhere to the surface and internal pores of the activated carbon in the first-stage biological fluidized bed. At this time, the quantity and variety of microorganisms in the source water are relatively large, and the microorganisms attach quickly. Moreover, the naturally occurring microorganisms in the source water have long-term contact with the organic matters in the water at the water source, forming a specific food chain, which can more effectively remove most of the organic matters in the source water. In the water entering the second-stage biological fluidized bed, the concentration of organic matters is relatively low, and most of them are intermediate products after ozone oxidation and decomposition. After high-concentration ozone contact oxidation in the second-stage ozone oxidation tank, the quantity of microorganisms is also relatively small. During the operation of the second-stage biological fluidized bed, a microbial population for removing intermediate products and growing under low-concentration organic matters is gradually formed. Since the sources and preparation processes of coal-based activated carbon and coconut shell activated carbon are different, the characteristic differences between the two activated carbons are large. The coal-based activated carbon has a smaller specific surface area and porosity and a larger density, while the coconut shell activated carbon has a larger specific surface area and porosity and a smaller density. By adjusting the activated carbon filled in different biological fluidized beds in the present invention, it is beneficial to regulate the distribution of microbial populations in the biological fluidized beds. Research shows that the system under this setting can better remove the organic matters in the source water.

[0020] On the other hand, a two-stage ozone biological fluidized bed water purification treatment process provides the above two-stage ozone biological fluidized bed water purification treatment system, and the raw water is sequentially passed through the first-stage ozone oxidation tank, the first-stage biological fluidized bed, the second-stage ozone oxidation tank and the second-stage biological fluidized bed for treatment.

[0021] In some embodiments, the ozone dosage in the first-stage ozone oxidation tank is 0.5 - 2 mg / L; the hydraulic retention time in the ozone oxidation zone is 5 - 20 min.

[0022] In some embodiments, the ozone dosage in the second-stage ozone oxidation tank is 2 - 5 mg / L, and the hydrogen peroxide dosage is 0 - 2 mg / L; the hydraulic retention time is 5 - 20 min.

[0023] In some embodiments, the ratio of the ozone dosage in the first-stage ozone oxidation tank to the ozone dosage in the second-stage ozone oxidation tank is 1:3 - 8. Research shows that under this condition, the treatment effect on the source water is better.

[0024] In a third aspect, an application of the above two-stage ozone biological fluidized bed water purification treatment system or two-stage ozone biological fluidized bed water purification treatment process in treating micro-polluted source water into drinking water.

[0025] The principle of the present invention is as follows: When the dual-stage ozone biological fluidized bed water purification treatment system of the present invention operates, raw water enters the ozone reaction zone from the upper part of the first-stage ozone oxidation tank. Ozone is added to the lower part of the ozone reaction zone through the first ozone aeration device. Ozone and raw water form an up-and-down convection of gas and water in the ozone reaction zone, and ozone and raw water fully contact and react. Then the effluent enters the sedimentation zone from the bottom of the ozone reaction zone. A sedimentation structure is arranged in the sedimentation zone, and large-particle pollutants such as algae, waterweeds, and sediment in the raw water are separated out. The water enters the water outlet from the upper part of the sedimentation structure and discharges from the first-stage ozone oxidation tank. The effluent of the first-stage ozone oxidation tank enters the first-stage biological fluidized bed by self-flow or water pump pressurization. The bottom of the first-stage biological fluidized bed is filled with a cobblestone support layer and an appropriate amount of granular activated carbon. The activated carbon is in a fluidized state under the action of water flow, and then discharges from the upper water outlet of the first-stage biological fluidized bed and enters the second-stage ozone oxidation tank. After further reacting with ozone and hydrogen peroxide in the second-stage ozone oxidation tank, it discharges from the upper water outlet of the second-stage ozone oxidation tank. The effluent enters the second-stage biological fluidized bed by self-flow or water pump pressurization. The bottom of the second-stage biological fluidized bed is filled with a cobblestone support layer and an appropriate amount of granular activated carbon. The activated carbon is in a fluidized state under the action of water flow, and then discharges from the upper water outlet of the second-stage biological fluidized bed.

[0026] The present invention is a water purification treatment process integrating ozone oxidation, advanced ozone oxidation, ozone catalytic oxidation, cavitation, and biological oxidation. It is placed at the front end of the conventional raw water treatment process (coagulation + sedimentation + filtration + disinfection). Raw water first enters the first-stage ozone oxidation reaction tank, and ozone reacts with pollutants in the raw water. Since there are many types of pollutants in the raw water, there are competitive reactions among different pollutants. Pollutants that are easily directly oxidized by ozone, such as microbial pollutants (such as bacteria, viruses, algae, etc.), reducing inorganic pollutants (such as divalent iron, divalent manganese, sulfides, etc.), and highly reactive organic pollutants (such as phenols, olefins, etc.), are preferentially oxidized and removed by ozone in the ozone reaction zone of the first-stage ozone oxidation tank, and then enter the sedimentation zone, where large-particle pollutants such as algae, sediment, and shells are removed. The effluent of the first-stage ozone oxidation tank passes through the upper water outlet and then enters the first-stage biological fluidized bed by self-flow or water pump pressurization. The first-stage biological fluidized bed is filled with high-hardness wear-resistant fillers and activated carbon. The fillers and activated carbon are in a fluidized state under the action of water flow. The effluent of the first-stage ozone oxidation tank contains extremely high dissolved oxygen, providing favorable conditions for the growth and reproduction of microorganisms. Microorganisms attach and grow on the surface and internal pores of the fillers, and degrade ammonia nitrogen, small-molecule organic matter, and reducing substances such as iron, manganese, and sulfides in the water through biological action. The first-stage ozone biological fluidized bed mainly plays a role in biological degradation, and refractory organic pollutants such as odor substances, pesticides, and antibiotics enter the second-stage ozone biological fluidized bed with the effluent.

[0027] In the secondary ozone oxidation tank, a cavitation jet aerator is used for ozone aeration, and hydrogen peroxide is added at the same time. Under the action of ozone, hydrogen peroxide generates active groups such as hydroxyl radicals. These active groups oxidize and decompose and partially mineralize odor substances, pesticides, antibiotics, etc. At the same time, during the cavitation process, the cavitation jet aerator generates a local high temperature of thousands of degrees Celsius to conduct high-temperature oxidation of extremely low-concentration refractory organic compounds, achieving the ultimate removal function of organic compounds. The effluent of the secondary ozone oxidation tank passes through the upper water outlet and then enters the secondary biological fluidized bed by gravity flow or under the pressure of a water pump. High-hardness wear-resistant fillers are filled in the secondary biological fluidized bed. Under the action of water flow, the fillers are in a fluidized state. The effluent of the secondary ozone oxidation tank contains a very high dissolved oxygen, providing favorable conditions for the growth and reproduction of microorganisms. Microorganisms attach and grow on the surface and inside the pore channels of the fillers, and further degrade the small-molecule organic compounds and ammonia nitrogen, etc. after the oxidation and decomposition of macromolecule refractory organic compounds by biological action, free radicals and cavitation. The secondary ozone oxidation tank mainly plays the role of advanced oxidation and mineralization, and the secondary biological fluidized bed mainly enriches special oligotrophic bacteria groups that degrade refractory organic compounds and the organic compounds after their decomposition.

[0028] Advantages of the present invention (1) The two-stage ozone biological fluidized bed water purification treatment process provided by the present invention adopts a hierarchical treatment form. In the first stage, it mainly plays the role of settling large particles, and uses biological degradation to remove small-molecule organic compounds, ammonia nitrogen, iron, manganese and other reducing substances, reducing the subsequent ozone consumption. In the second stage, a cavitation aeration form is adopted, hydrogen peroxide is added, and the cavitation effect and free radical effect are used to oxidize and decompose refractory organic compounds such as odor substances, pesticides, antibiotics, etc. and achieve partial mineralization. Then, through the biological action of the secondary biological fluidized bed, the organic compounds after oxidation and decomposition are degraded to the limit. Different pollutants in the source water are treated hierarchically in the most suitable way, solving the problems of large ozone dosage, low ozone utilization rate and difficult improvement of oxidation efficiency in the conventional one-stage ozone biological fluidized bed. (2) The two-stage ozone biological fluidized bed water purification treatment process provided by the present invention is a water purification treatment process integrating ozone oxidation, ozone advanced oxidation, ozone catalytic oxidation, cavitation and biological oxidation. Placed at the front end of the conventional treatment process (coagulation + sedimentation + filtration + disinfection), it can achieve deep removal of refractory organic compounds. Compared with the conventional one-stage ozone biological fluidized bed, the removal rates of refractory organic compounds such as odor substances, pesticides, antibiotics, etc. and ammonia nitrogen can be increased by 30% - 40%, and the ozone dosage can be saved by 20% - 30%.

[0029] (3) The two-stage ozone biological fluidized bed water purification treatment process provided by the present invention has the two-stage biological fluidized beds being independent of each other. Each stage can cultivate its own unique microbial population suitable for the water quality characteristics of this stage. The distribution of microbial flora in the two-stage biological fluidized beds is richer and more targeted. The microbial flora in the first-stage biological fluidized bed is mostly eutrophic flora, suitable for degrading easily biodegradable substances. The microbial flora in the second-stage biological fluidized bed is mostly oligotrophic flora, suitable for degrading hardly biodegradable substances and intermediate products of their oxidation and decomposition, etc. Therefore, the microbial community structure in the two-stage biological fluidized bed is richer and has degradation targeting. The microorganisms in each stage can better adapt to different substrates and environmental conditions, which is beneficial to improving the stability of the operation effect of the treatment system.

[0030] (4) The two-stage ozone biological fluidized bed water purification treatment process provided by the present invention can be applied to most surface water source water plants, with strong practicability and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0032] Figure 1 It is the process flow diagram of the two-stage ozone biological fluidized bed water purification treatment process of Embodiment 1 of the present invention; Wherein, 1. water inlet; 2. ozone reaction zone; 3. sedimentation zone; 4. first ozone aeration device; 5. sludge collection zone; 6. ozone tail gas destructor; 7. booster pump; 8. first-stage biological fluidized bed; 9. second-stage ozone reaction tank; 10. second-stage biological fluidized bed; 11. hydrogen peroxide dosing system; 12. second ozone aeration device; 13. ozone dosing system; 14. water outlet. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0034] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0035] Micro-polluted raw water is a technical term in the field of water treatment, which refers to the raw water whose partial water quality indicators exceed the requirements of the drinking water source health standard due to the influence of industrial wastewater and domestic sewage discharged. In river water sources, it is manifested as the exceeding of indicators such as ammonia nitrogen, total phosphorus, chromaticity, and organic matter in the drinking water source health standard. In lake and reservoir water sources, it is manifested as the eutrophication of the reservoir and lake water bodies, and the growth of algae during a certain period, resulting in water quality deterioration and a significant increase in odor.

[0036] In view of the problems that the existing water purification treatment processes have low removal efficiency for refractory organic matter, odor substances, and ammonia nitrogen when treating polluted surface water sources, the present invention proposes a two-stage ozone biological fluidized bed water purification treatment system and process.

[0037] A typical embodiment of the present invention provides a two-stage ozone biological fluidized bed water purification treatment system, which is used to be arranged at the front end of a conventional water purification treatment system to pre-treat raw water; it sequentially includes a first-stage ozone oxidation tank, a first-stage biological fluidized bed, a second-stage ozone oxidation tank, and a second-stage biological fluidized bed according to the raw water flow direction; Among them, the first-stage ozone oxidation tank includes an outer tank body and an inner tank body. The outer tank body is enclosed, and an inlet and an outlet are opened at the upper part of the outer tank body. The inlet is connected to the inner tank body through a pipeline. A sludge collection area is arranged at the bottom of the outer tank body. The inner tank body is a cylindrical structure with both upper and lower ends open, and the inner tank body is suspended in the outer tank body. The top of the inner tank body is higher than the water surface of the first-stage ozone oxidation tank. The channel between the side wall of the outer tank body and the side wall of the inner tank body is set as a sedimentation area, and a sedimentation structure is arranged in the sedimentation area. The inside of the inner tank body is an ozone oxidation area, and a first ozone aeration device is arranged at the lower part of the ozone oxidation area. The flow direction of the raw water in the first-stage ozone oxidation tank is sequentially the ozone oxidation area, the sedimentation area, and the outlet; Both the first-stage biological fluidized bed and the second-stage biological fluidized bed are enclosed, and a fluidized layer is arranged in both the first-stage biological fluidized bed and the second-stage biological fluidized bed. The fluidized layer is filled with fillers and activated carbon; the second-stage ozone oxidation tank is enclosed and a second ozone aeration device and a hydrogen peroxide dosing device are arranged inside; the first ozone aeration device and the second ozone aeration device are connected to an ozone source, and the hydrogen peroxide dosing device is connected to a hydrogen peroxide source.

[0038] In some embodiments, an ozone tail gas destructor is arranged at the top of the first-stage ozone oxidation tank. In some embodiments, the sedimentation structure is a lamella and / or a lamellar tube.

[0039] In some embodiments, the first ozone aeration device is an aeration titanium disc.

[0040] In a specific embodiment, the primary ozone oxidation tank is a square or circular tank body with a sealed top and is equipped with an ozone tail gas destructor, including an ozone reaction zone, a sedimentation zone, and a sludge collection zone; the ozone reaction zone is a square or circular tank body located in the middle of the primary ozone oxidation tank. The top of the reaction zone is 0.5 m to 0.8 m above the water surface, the height of the reaction zone is 2 / 3 to 3 / 4 of the height of the primary ozone oxidation tank, and it is 1.5 to 2.0 m from the top of the bottom sludge collection zone. A first ozone aeration device is arranged 0.5 to 1.0 m from the bottom inside the reaction zone. The first ozone aeration device can be an aeration titanium disc, and the first ozone aeration device is connected to an ozone generator through pipelines, valves, etc. The source water enters the upper part of the middle ozone reaction zone through a pipeline; between the ozone reaction zone and the primary ozone oxidation tank is the sedimentation zone, and the sedimentation form is inclined plate / inclined tube sedimentation. Inclined plates / inclined tubes are arranged in the upper-middle position of the sedimentation zone. There is a 1.0 to 2.0 m clear water zone above the inclined plates / inclined tubes. The length of the inclined plates is 0.8 - 1.2 m, the spacing between the inclined plates is 50 - 80 mm, and the inclination angle is 45° - 60°; the lower part of the ozone reaction zone is the sludge collection zone, and the sludge collection zone is an inverted conical sludge hopper. The slope of the sludge hopper is 45% - 60°, and the bottom of the sludge hopper is connected to a sludge discharge pipe and a valve. The effective depth of the primary ozone oxidation tank is not less than 9.0 m, and the water outlet is arranged at the upper part of the primary ozone oxidation tank.

[0041] In some embodiments, the primary biological fluidized bed is a closed tank body structure, with an inlet arranged at the bottom and an outlet arranged at the upper part.

[0042] In some embodiments, from bottom to top in the primary biological fluidized bed are a uniform water distribution zone, a supporting layer, and a fluidized layer.

[0043] In some embodiments, an ozone tail gas destructor is arranged at the top of the primary biological fluidized bed.

[0044] In a specific embodiment, the primary biological fluidized bed is a square or circular tank body with a sealed top and is equipped with an ozone tail gas destructor, an inlet is arranged at the bottom, an outlet is arranged at the upper part, and from bottom to top inside are a uniform water distribution zone, a supporting layer, and a fluidized layer. The supporting layer can adopt 3 to 4 layers of graded cobblestones, and the filler of the fluidized layer adopts a high-hardness, wear-resistant, and lightweight filler, which can be coal-based / coconut shell activated carbon. The height of the fluidized layer is 1.5 to 2.0 m, and the particle size of the biological fluidized bed filler is 0.5 - 1.0 mm.

[0045] The water outlet of the primary ozone oxidation tank can enter the primary biological fluidized bed by gravity or can enter the primary biological fluidized bed by being pressurized by a water pump.

[0046] In some embodiments, the activated carbon filled in the primary biological fluidized bed is coal-based activated carbon, and the activated carbon filled in the secondary biological fluidized bed is coconut shell activated carbon.

[0047] In some embodiments, in the secondary ozone oxidation tank, an inlet is arranged at the upper part and an outlet is arranged at the bottom.

[0048] In some embodiments, an ozone tail gas destructor is provided at the top of the secondary ozone oxidation tank. In some embodiments, the second ozone aeration device can be an aeration titanium disk, a jet aerator or a self-excited pulsed cavitation jet device.

[0049] In a specific embodiment, the secondary ozone oxidation tank is a square or circular tank body, the top is airtight, an ozone tail gas destructor is provided, a water inlet is provided at the upper part, a water outlet is provided at the bottom, a second ozone aeration device is provided at a distance of 0.5 to 1.0 m from the bottom inside, the second ozone aeration device can be an aeration titanium disk, a jet aerator or a self-excited pulsed cavitation jet device, and a hydrogen peroxide dosing device is provided inside.

[0050] In some embodiments, the secondary biological fluidized bed is a closed tank structure, a water inlet is provided at the bottom, and a water outlet is provided at the upper part.

[0051] In some embodiments, from bottom to top inside the secondary biological fluidized bed are a uniform water distribution area, a supporting layer and a fluidized layer.

[0052] In some embodiments, an ozone tail gas destructor is provided at the top of the secondary biological fluidized bed.

[0053] In a specific embodiment, the secondary biological fluidized bed is a square or circular tank body, the top is airtight, an ozone tail gas destructor is provided, a water inlet is provided at the bottom, a water outlet is provided at the upper part, from bottom to top inside are a uniform water distribution area, a supporting layer and a fluidized layer, the supporting layer can adopt 3 to 4 levels of graded cobblestones, the fluidized layer filler adopts a high-hardness wear-resistant light filler, which can be coal-based / coconut shell activated carbon, the height of the fluidized layer is 1.5 to 2.0 m, and the particle size of the biological fluidized bed filler is 0.5 to 1.0 mm.

[0054] The effluent of the secondary ozone oxidation tank can enter the secondary biological fluidized bed by gravity or can enter the secondary biological fluidized bed by being pressurized by a water pump.

[0055] The effective water depth of the primary ozone oxidation tank, the secondary ozone oxidation tank, the primary biological fluidized bed and the secondary biological fluidized bed is not less than 9.0 m.

[0056] The ozone source can be an ozone generation system, and the ozone generation system, the ozone aeration device and pipelines, valves, flow meters, etc. constitute an ozone dosing system.

[0057] The hydrogen peroxide source can be a hydrogen peroxide storage tank, and the hydrogen peroxide storage tank, metering pump and pipelines, valves, flow meters, etc. constitute a hydrogen peroxide dosing system.

[0058] On the other hand, a two-stage ozone biological fluidized bed water purification treatment process provides the above two-stage ozone biological fluidized bed water purification treatment system, and raw water is sequentially introduced into a first-stage ozone oxidation tank, a first-stage biological fluidized bed, a second-stage ozone oxidation tank, and a second-stage biological fluidized bed for treatment.

[0059] In some embodiments, the ozone dosage in the first-stage ozone oxidation tank is 0.5 - 2 mg / L; the hydraulic retention time in the ozone oxidation zone is 5 - 20 min.

[0060] In some embodiments, in the first-stage biological fluidized bed, the contact time between the fluidized layer and water is 5 - 30 min.

[0061] In some embodiments, the ozone dosage in the second-stage ozone oxidation tank is 2 - 5 mg / L, the hydrogen peroxide dosage is 0 - 2 mg / L, and the hydraulic retention time is 5 - 20 min. Among them, the dosage of hydrogen peroxide is not 0.

[0062] In some embodiments, in the second-stage biological fluidized bed, the contact time between the fluidized layer and water is 5 - 30 min.

[0063] In some embodiments, the ratio of the ozone dosage in the first-stage ozone oxidation tank to the ozone dosage in the second-stage ozone oxidation tank is 1:3 - 8.

[0064] In the third aspect, an application of the above two-stage ozone biological fluidized bed water purification treatment system or two-stage ozone biological fluidized bed water purification treatment process in treating slightly polluted raw water into drinking water.

[0065] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific examples and comparative examples.

[0066] Examples A two-stage ozone biological fluidized bed water purification treatment system, as Figure 1 shown, includes a reaction system, an ozone dosing system 13, and a hydrogen peroxide dosing system 11. The reaction system is composed of a first-stage ozone reaction tank, a first-stage biological fluidized bed 8, a second-stage ozone reaction tank 9, and a second-stage biological fluidized bed 10 connected in sequence. The water depth of each ozone reaction tank is not less than 9.0 m.

[0067] An inlet 1 is provided on the upper side wall of the first-stage ozone oxidation tank, and the top is sealed. An ozone tail gas destructor 6 and a breathing valve (for balancing the internal and external air pressures) are provided. Inside the first-stage ozone oxidation tank, there are an ozone reaction zone 2, a sedimentation zone 3, and a sludge collection zone 5. The sedimentation zone 3 is located between the side wall of the ozone reaction zone 2 and the side wall of the first-stage ozone oxidation tank. A first ozone aeration device 4 connected to the ozone dosing system 13 is provided in the ozone reaction zone 2. It adopts upper inlet and lower outlet. The ozone dosing amount is 0.5 mg / L, and the contact time between ozone and water is 15 minutes. The effluent enters the inclined plate sedimentation device in the sedimentation zone 3 from the lower outlet. The inclined plate of the inclined plate sedimentation device has a length of 0.8 m, a spacing of 50 mm between inclined plates, an inclination angle of 60°, and a protection height of 1.0 m in the clear water zone. The water is pumped into the first-stage biological fluidized bed from the upper outlet of the inclined plate sedimentation device through a booster pump 7, and the residence time is 20 minutes.

[0068] The top of the first-stage biological fluidized bed is sealed, and an ozone tail gas destructor is provided. It adopts lower inlet and upper outlet. Inside, from bottom to top, there are a uniform water distribution zone, a supporting layer, and a fluidized layer. The supporting layer can adopt 3-layer graded cobblestones, on which coal-based activated carbon with a particle size of 0.4 - 0.6 mm is filled, with a filling thickness of 1.5 m, an expansion ratio of 45%, and a contact time with water of 10 minutes. The effluent enters the second-stage ozone reaction tank.

[0069] The top of the second-stage ozone reaction tank 9 is sealed, and an ozone tail gas destructor and a breathing valve (for balancing the internal and external air pressures) are provided. It adopts upper inlet and lower outlet. Inside, a second ozone aeration device 12 is provided. The second ozone aeration device 12 is connected to the ozone dosing system 13. The ozone dosing amount is 4 mg / L, and the hydrogen peroxide dosing system 11 doses hydrogen peroxide into the second-stage ozone reaction tank 9. The hydrogen peroxide dosing amount is 2 mg / L. The contact time between ozone / hydrogen peroxide and water is 15 minutes. The effluent enters the second-stage biological fluidized bed inlet system from the lower outlet through a booster pump.

[0070] The top of the second-stage biological fluidized bed 10 is sealed, and an ozone tail gas destructor is provided. It adopts lower inlet and upper outlet. Inside, from bottom to top, there are a uniform water distribution zone, a supporting layer, and a fluidized layer. The supporting layer can adopt 4-layer graded cobblestones, on which coconut shell activated carbon with a particle size of 0.4 - 0.6 mm is filled, with a filling thickness of 1.5 m, an expansion ratio of 45%, and a contact time with water of 10 minutes.

[0071] The above system was used to treat the water from a certain Yellow River water source reservoir (permanganate index: 7.31 mg / L, ammonia nitrogen: 0.98 mg / L, 2-MIB: 360.5 ng / L, GSM: 36.4 ng / L, SS: 24 mg / L). After detection, the average permanganate index of the effluent was 0.37 mg / L, the ammonia nitrogen in the effluent was less than 0.02 mg / L, the 2-MIB concentration was below the detection limit (<2.2 ng / L), the GSM concentration was below the detection limit (<3.8 ng / L), and bromate was not detected.

[0072] Comparative Example 1 The existing single-stage ozone-hydrogen peroxide advanced oxidation biological fluidized bed system (i.e., one-stage ozone reaction tank and one-stage biological fluidized bed in Example 1 were omitted) was used to treat the water from a certain Yellow River water source reservoir (permanganate index: 7.31 mg / L, ammonia nitrogen: 0.98 mg / L, 2-MIB: 360.5 ng / L, GSM: 36.4 ng / L, SS: 24 mg / L). The ozone dosage was 6.0 mg / L, and the hydrogen peroxide dosage was 2 mg / L. After detection, the average permanganate index of the effluent was 1.32 mg / L, the ammonia nitrogen in the effluent was less than 0.18 mg / L, the 2-MIB concentration was 9.2 ng / L, the GSM concentration was below the detection limit (<3.8 ng / L), and bromate was not detected.

[0073] Comparative Example 2 The system in which two existing single-stage ozone-hydrogen peroxide advanced oxidation biological fluidized bed systems were directly connected in series (i.e., in Example 1, the structure of the one-stage ozone reaction tank was the same as that of the two-stage ozone reaction tank, and the structure of the one-stage biological fluidized bed was the same as that of the two-stage biological fluidized bed) was used to treat the water from a certain Yellow River water source reservoir (permanganate index: 7.31 mg / L, ammonia nitrogen: 0.98 mg / L, 2-MIB: 360.5 ng / L, GSM: 36.4 ng / L, SS: 24 mg / L). The one-stage ozone dosage was 2 mg / L, the one-stage hydrogen peroxide dosage was 1 mg / L, the two-stage ozone dosage was 4 mg / L, and the two-stage hydrogen peroxide dosage was 1 mg / L. After detection, the average permanganate index of the effluent was 0.73 mg / L, the ammonia nitrogen in the effluent was less than 0.02 mg / L, the 2-MIB concentration was 5.1 ng / L, the GSM concentration was below the detection limit (<3.8 ng / L), and bromate was not detected.

[0074] By comparing the sampling and detection results of the effluents in the examples and Comparative Examples 1-2, it can be found that the two-stage ozone biological fluidized bed water purification treatment system and process of the present invention can effectively remove refractory organic matters, ammonia nitrogen, 2MIB, and GSM in water, and the bromate does not exceed the standard; at the same time, the ozone dosage is reduced (by 25%), the treatment effect is stable, and the operation cost is low.

[0075] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A two-stage ozone biological fluidized bed water purification treatment system, characterized in that it is used for It is arranged at the front end of a conventional water purification treatment system to pre-treat raw water, and successively includes a first-stage ozone oxidation tank, a first-stage biological fluidized bed, a second-stage ozone oxidation tank, and a second-stage biological fluidized bed according to the raw water flow direction; Among them, the first-stage ozone oxidation tank includes an outer tank body and an inner tank body. The outer tank body is enclosed, and an inlet and an outlet are opened at the upper part of the outer tank body. The inlet is connected to the inner tank body through a pipeline. A sludge collection area is arranged at the bottom of the outer tank body. The inner tank body is a cylindrical structure with both upper and lower ends open, and the inner tank body is suspended in the outer tank body. The top of the inner tank body is higher than the water surface of the first-stage ozone oxidation tank. The channel between the side wall of the outer tank body and the side wall of the inner tank body is set as a sedimentation area, and a sedimentation structure is arranged in the sedimentation area. The inside of the inner tank body is an ozone oxidation area, and a first ozone aeration device is arranged at the lower part of the ozone oxidation area. The flow direction of the raw water in the first-stage ozone oxidation tank is successively the ozone oxidation area, the sedimentation area, and the outlet; Both the first-stage biological fluidized bed and the second-stage biological fluidized bed are enclosed, and a fluidized bed is arranged in both the first-stage biological fluidized bed and the second-stage biological fluidized bed. The fluidized bed is filled with packing and activated carbon. The second-stage ozone oxidation tank is enclosed and a second ozone aeration device and a hydrogen peroxide dosing device are arranged inside. The first ozone aeration device and the second ozone aeration device are connected to an ozone source, and the hydrogen peroxide dosing device is connected to a hydrogen peroxide source.

2. The dual-stage ozone biological fluidized bed water purification treatment system according to claim 1, wherein, The sedimentation structure is inclined plates and / or inclined tubes; Or, the first ozone aeration device is an aeration titanium disc; Or, an ozone tail gas destructor is arranged at the top of the first-stage ozone oxidation tank.

3. The dual-stage ozone biological fluidized bed water purification treatment system according to claim 1, characterized in that, The first-stage biological fluidized bed is a closed tank structure, with an inlet arranged at the bottom and an outlet arranged at the upper part; Or, from bottom to top in the first-stage biological fluidized bed are a uniform water distribution area, a supporting layer, and a fluidized bed; Or, an ozone tail gas destructor is arranged at the top of the first-stage biological fluidized bed.

4. The dual-stage ozone biological fluidized bed water purification treatment system according to claim 1, characterized in that, In the second-stage ozone oxidation tank, an inlet is arranged at the upper part and an outlet is arranged at the bottom; Or, the second ozone aeration device can be an aeration titanium disc, a jet aerator, or a self-excited pulsed cavitation jet device; Or, an ozone tail gas destructor is arranged at the top of the second-stage ozone oxidation tank.

5. The dual-stage ozone biological fluidized bed water purification treatment system according to claim 1, characterized in that, The second-stage biological fluidized bed is a closed tank structure, with an inlet arranged at the bottom and an outlet arranged at the upper part; Or, from bottom to top in the second-stage biological fluidized bed are a uniform water distribution area, a supporting layer, and a fluidized bed; Or, an ozone tail gas destructor is arranged at the top of the second-stage biological fluidized bed.

6. The two-stage ozone biological fluidized bed water purification treatment system according to claim 1, wherein The activated carbon filled in the first-stage biological fluidized bed is coal-based activated carbon, and the activated carbon filled in the second-stage biological fluidized bed is coconut shell activated carbon.

7. A two-stage ozone biological fluidized bed water purification treatment process, characterized in that, There is provided a two-stage ozone biological fluidized bed water purification treatment system according to any one of claims 1 to 6, and the raw water enters the first-stage ozone oxidation tank, the first-stage biological fluidized bed, the second-stage ozone oxidation tank, and the second-stage biological fluidized bed in sequence for treatment.

8. The two-stage ozone biological fluidized bed water purification treatment process according to claim 7, characterized in that, The ozone dosage in the first-stage ozone oxidation tank is 0.5 - 2 mg / L, and the hydraulic retention time in the ozone oxidation area is 5 - 20 min; Or, in the first-stage biological fluidized bed, the contact time between the fluidized bed and water is 5 - 30 min; Or, the ozone dosage in the second-stage ozone oxidation tank is 2 - 5 mg / L, the hydrogen peroxide dosage is 0 - 2 mg / L, and the hydraulic retention time is 5 - 20 min, wherein the dosage of hydrogen peroxide is not 0; Alternatively, in the secondary biological fluidized bed, the contact time between the fluidized bed and water is 5 - 30 min.

9. The dual-stage ozone biological fluidized bed water purification treatment process according to claim 7, characterized in that, The ratio of the ozone dosage in the primary ozone oxidation tank to the ozone dosage in the secondary ozone oxidation tank is 1:3 - 8.

10. Application of the two-stage ozone biological fluidized bed water purification treatment system according to any one of claims 1 - 5 or the two-stage ozone biological fluidized bed water purification treatment process according to any one of claims 7 - 9 in treating micro-polluted source water into drinking water.

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