Treatment device for removing new pollutants in water body based on catalytic ozone-biological coupling process

Abstract

The invention provides a treatment device for removing new pollutants in a water body based on a catalytic ozone-biological coupling process. The device comprises a catalytic ozonation reactor and a bioreactor, wherein the catalytic ozonation reactor is internally provided with an activated carbon filter layer (the filling height is 0.1-0.2 m, and the particle size is 1-3mm) and a natural manganese sand catalyst filler layer (17.4 wt% of Mn, 9.4 wt% of Al, 7.6 wt% of Fe, and the filling height is 0.3-0.6 m), and new pollutants are subjected to oxidative degradation through hydroxyl radicals generated by catalytic ozonation; the bioreactor is loaded with a directionally domesticated pseudomonas biological membrane, biodegradation is carried out by utilizing dissolved oxygen (5-8 mg / L) of ozone effluent, and the backwashing period (10-15 days) is dynamically adjusted by monitoring the pollutant removal rate in real time. According to the device, through three-stage combination of adsorption, catalytic oxidation and biological treatment, the removal rate of new pollutants is larger than or equal to 70% (the removal rate of typical pollutants carbamazepine and sulfamethoxazole reaches 90% or above), and meanwhile, the advantage of low cost of a natural manganese sand catalyst is achieved; and the technical bottlenecks of low treatment efficiency, high operation cost and high by-product risk of the conventional process are solved.

Description

Technical Field

[0001] The invention belongs to a method for treating the effluent of urban sewage treatment plants, and particularly relates to a catalytic ozone oxidation-biological treatment device for removing emerging pollutants in domestic sewage. Background Art

[0002] In recent years, with the continuous expansion of the monitoring level and scope, more and more environmental pollutants have received attention. Compared with conventional pollutants, such pollutants are collectively referred to as emerging pollutants. Emerging pollutants often have ecological toxicity, persist in the environment and have a certain degree of bioaccumulation. Even if their concentration in the environment is very low, they may pose significant environmental and health risks, and their harm is potential and hidden. Different from conventional pollutants such as sulfur dioxide, nitrogen oxides, and PM2.5, the types of emerging pollutants are numerous and continuously increasing.

[0003] The emerging pollutants in domestic sewage mainly include persistent organic pollutants (such as polychlorinated biphenyls), endocrine disruptors (such as bisphenol A, nonylphenol), antibiotics (such as ofloxacin, amoxicillin), and microplastics, etc. These pollutants originate from the widespread use of pharmaceuticals, personal care products, industrial chemicals, and plastic products, and enter sewage treatment plants through domestic sewage, industrial wastewater and other channels.

[0004] The total concentration range of emerging pollutants in the effluent of sewage treatment plants in China is 1392 - 35453 ng / L, among which the residual concentration of antibiotics is relatively high. For example, the concentration of ofloxacin in the effluent of some plants still reaches 226 ng / L, posing a medium ecological risk.

[0005] The activated sludge process and the biofilm process are the most widely used sewage treatment processes in China at present, and the microbial density is high and the species are rich in the stage of sewage biological treatment. Although after sewage treatment, a part of emerging pollutants will be reduced with the removal of biomass, there are still quite a number of emerging pollutants discharged with the effluent. This is because the biological treatment process mainly based on the activated sludge process is designed for conventional pollutants such as nitrogen and phosphorus, and the removal efficiency of emerging pollutants is generally low (such as the antibiotic removal rate is only 5.88% - 74.16%), and the conventional biological process is easily poisoned by high-concentration emerging pollutants and loses its activity. Physical technologies (such as adsorption, filtration) have poor effects on highly soluble pollutants, and chemical technologies (such as ozone oxidation) may produce toxic by-products. Summary of the Invention

[0006] To overcome the disadvantages of the above-mentioned existing technologies, the purpose of the present invention is to provide a combined device for advanced wastewater treatment. Through the three-stage combination of adsorption-catalytic oxidation-biological treatment, it breaks through the limitations of single technologies and improves the removal efficiency of new pollutants. First, through the combined action of activated carbon adsorption and natural manganese sand catalyst packing to catalyze ozone, it can not only adsorb new pollutants in water, but also generate more hydroxyl radicals with strong oxidation effects, destroying the structure of new pollutants in water, reducing toxicity, and turning them into small molecular substances that are easily utilized by organisms, improving the biodegradability of wastewater. The dissolved oxygen in the ozone-treated effluent is significantly increased, which can meet the oxygen demand for subsequent biological treatment. After the ozone in the ozone effluent decomposes, it undergoes BAF biological treatment to further degrade the low-concentration new pollutants in the ozone effluent, thereby achieving the efficient removal of new pollutants under low-cost conditions and promoting the healthy process of water quality.

[0007] Moreover, the manganese sand used in this device is natural manganese sand, with low procurement costs; it is loaded with various metal oxides, which can achieve efficient catalysis of ozone and is especially suitable for use in wastewater treatment plants.

[0008] This device is compatible with existing wastewater treatment plant facilities and has low transformation difficulty (only the catalyst needs to be replaced and the bacterial agent needs to be added), and it can improve the quality of wastewater.

[0009] To achieve the above purpose, the technical solution adopted by the present invention is:

[0010] A treatment device for removing new pollutants in water based on a catalytic ozone-biological coupling process, characterized in that it includes a catalytic ozone column reactor (5) and a biological reactor (9), wherein:

[0011] Inside the catalytic ozone column reactor (5), an activated carbon adsorption layer (11) and a natural manganese sand catalyst packing (12) are sequentially arranged from bottom to top. The height of the activated carbon filtration layer is 0.1 - 0.2 m, and the particle size is 1 - 3 mm. The natural manganese sand catalyst packing is rich in metal elements such as Mn, Al, and Fe, and the filling height is 0.3 - 0.6 m, and the particle size is 1.5 mm;

[0012] Inside the biological reactor (9), a specific biofilm after being directionally domesticated for new pollutants is filled, and the height is 0.5 m;

[0013] The biological oxygen demand of the biological reactor (9) is provided by the dissolved oxygen rich in the ozone effluent, and is not provided by an aeration pump, greatly saving the electricity cost;

[0014] The backwash effluent of the biological reactor (9) is connected to the inlet pipe and re-introduced into the device for treatment, reducing the waste of water resources;

[0015] There are openings at 0.1 m and 0.5 m on the side of the ozone column reactor (5), through which activated carbon or manganese sand can be added to or removed from the column. There are openings at 0.1 m, 0.2 m, 0.3 m, 0.4 m, and 0.5 m on the side of the bioreactor (9), through which the activity of the biofilm can be observed and the removal of pollutants in the water can be measured. The catalytic ozone reactor (5) can adjust the ozone dosage to 2 - 10 mg / L according to the real-time data of influent TOC, new pollutant concentration, pH, water temperature, etc. There is an air inlet at the bottom of the bioreactor (9), which is connected to an aeration pump (10). The aeration pump (10) is only turned on during backwashing and is turned off at other times. The backwashing frequency of the bioreactor (9) is linked to the removal efficiency of new pollutants and is turned on when the removal rate is lower than 70%.

[0016] This device combines a metal-loaded catalyst with a functional bacterium agent for the first time to achieve the oxidative-biological synergistic degradation of new pollutants. Through the three-stage combination of adsorption-catalytic oxidation-biological treatment, the limitations of single technologies are broken through. Description of the Drawings

[0017] Figure 1 It is a schematic diagram of a treatment device for removing new pollutants in water based on a catalytic ozone-biological coupling process according to the present invention.

[0018] Among them, 1 is an oxygen cylinder, 2 is an ozone generator, 3 is an influent water tank, 4 is a peristaltic pump, 5 is a catalytic ozone oxidation reaction column, 6 is a tail gas absorption column, 7 is an intermediate water tank, 8 is a peristaltic pump, 9 is a bioreaction column, 10 is an aeration pump, 11 is an activated carbon filter layer, 12 is a catalyst filling layer, and 13 is an effluent water tank.

[0019] Figure 2 It is a comparison chart of the removal rate of carbamazepine by a treatment device for removing new pollutants in water based on a catalytic ozone-biological coupling process.

[0020] Figure 3 It is a comparison chart of the removal rate of sulfamethoxazole by a treatment device for removing new pollutants in water based on a catalytic ozone-biological coupling process.

[0021] Figure 4 It is a comparison chart of the removal rate of norfloxacin by a treatment device for removing new pollutants in water based on a catalytic ozone-biological coupling process.

[0022] Figure 5 It is a comparison chart of the removal rate of sulfamethazine by a treatment device for removing new pollutants in water based on a catalytic ozone-biological coupling process.

[0023] Figure 6Removal rate comparison chart of ibuprofen by a treatment device for removing emerging pollutants from water based on a catalytic ozone-biological coupling process

[0024] Figure 7 Removal rate comparison chart of 2,4-D by a treatment device for removing emerging pollutants from water based on a catalytic ozone-biological coupling process

[0025] Figure 8 Removal rate comparison chart of bezafibrate by a treatment device for removing emerging pollutants from water based on a catalytic ozone-biological coupling process Detailed implementation manners

[0026] The present invention provides a treatment device for removing emerging pollutants from water based on a catalytic ozone-biological coupling process. The following describes the specific technical methods and devices of the present invention in detail and completely in combination with the accompanying drawings and specific implementation manners. The described specific implementation manners are only partial examples of the present invention, rather than all examples. All other examples obtained by those skilled in the art without creative efforts fall within the protection scope of the present invention. Detailed implementation manner one:

[0028] Taking the secondary effluent of a sewage treatment plant as the water quality background, 100-500 μg / L of emerging pollutants are added thereto respectively, and the device of the present invention is used to remove each emerging pollutant.

[0029] Specific implementation steps:

[0030] The sewage enters the water tank 3 to be collected, is conveyed by a water pump, and enters the catalytic ozone oxidation column reactor 5 through the water inlet.

[0031] The ozone obtained by the ozone generator 2 enters the catalytic ozone oxidation column reactor 5 through the air inlet.

[0032] After the sewage and ozone are mixed at the bottom, they first pass through the activated carbon filtration section 11. The height of the activated carbon filtration section 11 is 0.1-0.2 m, and the filled particle size is 1-3 mm.

[0033] After the sewage and ozone pass through the filtration section, they enter the manganese sand catalyst packing section 12. The manganese sand packing 12 acts as a catalyst to catalyze the heterogeneous advanced oxidation reaction of ozone and sewage, and at the same time catalyzes the decomposition of ozone. When the emerging pollutants in the water are at 500 μg / L, the removal rate of carbamazepine is 98%, the removal rate of sulfamethoxazole is 99%, the removal rate of norfloxacin is 95%, the removal rate of sulfamerazine is 99%, the removal rate of ibuprofen is 74%, the removal rate of 2,4-D is 65%, and the removal rate of bezafibrate is 77%.

[0034] The sewage and ozone then enter the intermediate water tank 7, enabling the ozone in the water to fully react and decompose, and the excess tail gas enters the tail gas absorption device 6. The residence time of the sewage here is 2 h.

[0035] The sewage enters the BAF bioreactor 9 from the intermediate water tank 7 for biochemical treatment. When the new pollutants in the water are at 500 μg / L, the removal rate of carbamazepine is 99%, the removal rate of sulfamethoxazole is 99%, the removal rate of norfloxacin is 99%, the removal rate of sulfamerazine is 99%, the removal rate of ibuprofen is 96%, the removal rate of 2,4-D is 82%, and the removal rate of bezafibrate is 87%.

[0036] The up-to-standard sewage after biochemical treatment enters the outlet water tank 13 for external discharge.

[0037] When the removal rate of the new pollutants in the effluent decreases, the biological column is cleaned.

[0038] Comparative Example 1:

[0039] The sewage quality is the same as that in the first specific embodiment, and the other reaction conditions are also the same. The sewage is only treated by BAF biological treatment to compare the effluent effects of this device and each unit. When the new pollutants in the water are at 500 μg / L, the removal rate of carbamazepine is 7%, the removal rate of sulfamethoxazole is 1%, the removal rate of norfloxacin is 65%, the removal rate of sulfamerazine is 0, the removal rate of ibuprofen is 32%, the removal rate of 2,4-D is 0, and the removal rate of bezafibrate is 7%.

Claims

1. A catalytic ozone oxidation reaction device, characterized in that, It includes a catalytic ozone reaction column (5), an activated carbon adsorption layer (11), and a natural manganese sand catalyst filler (12). The activated carbon adsorption layer (11) is located in the lower layer inside the ozone reaction column (5), with a filling height of 0.1 - 0.2 m and a particle size of 1 - 3 mm. The natural manganese sand catalyst filler (12) contains 17.4 wt% Mn, 9.4 wt% Al, and 7.6 wt% Fe, and is filled above the activated carbon adsorption layer (11), with a filling height of 0.3 - 0.6 m. The backwash effluent of the biological reactor (9) is connected to the inlet pipe and re-introduced into the device for treatment.

2. A linkage type biological treatment device, characterized in that, It includes the catalytic ozone reaction column as described in claim 1, and a biological reactor (9) connected thereto. The biological reactor (9) is loaded with a biofilm mainly composed of Pseudomonas sp. that has been directionally domesticated, and its removal efficiency for new pollutants is ≥ 70%, and the backwash cycle is 10 - 15 days.

3. The catalytic ozone oxidation reaction device according to claim 1, wherein A detachable filler maintenance port is provided at a height of 0.5 - 1 m in the middle of the catalytic ozone reaction column (5), with an opening diameter of ≥ 200 mm. The maintenance interval period is negatively correlated with the influent SS concentration: when SS ≤ 20 mg / L, the maintenance period is ≥ 90 days; when SS > 50 mg / L, the maintenance period is ≤ 30 days.

4. The linked biological treatment device according to claim 2, characterized in that, The source of dissolved oxygen in the biological reactor (9) is the undissolved dissolved oxygen in the effluent of the ozone reactor, and its concentration is maintained at 5 - 8 mg / L. The influent TOC load and the ozone dosage maintain a positive coupling relationship.

5. The device according to claim 2, characterized in that, The side of the biological reactor (9) has openings at different heights, which can monitor the removal rates of new pollutants at different heights.

6. The linkage type biological treatment device according to claim 2, characterized in that, The backwash cycle is related to the concentration of new pollutants in the effluent. When the removal rate of new pollutants in the effluent is lower than 50%, the backwash procedure is started.

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