Fluidized bed wastewater treatment method and system

Abstract

This invention discloses a fluidized bed wastewater treatment method and system, relating to the field of water treatment technology. The fluidized bed wastewater treatment method and system include the following steps: obtaining the calcium ion concentration in the wastewater; adding a catalyst to a fluidized bed reactor, and adding peroxybicarbonate or percarbonate to react with the wastewater; the wastewater contains a scale inhibitor with a concentration of less than or equal to 50 mg / L; the wastewater contains calcium ions... 2+ The concentration meter indicates that the calcium ion concentration is less than or equal to 500 mg / L. The catalyst comprises a support and an active component, wherein the active component is Co3O4 and / or CuO. This invention uses peroxybicarbonate (PMC) or percarbonate (SPC) as the treatment agent and employs a catalyst supported on cobalt / copper oxide as a fluidized bed support to simultaneously achieve multiple functions: eliminating scale inhibition, degrading organic pollutants, and promoting calcium carbonate crystallization.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and more specifically, to a fluidized bed wastewater treatment method and system. Background Technology

[0002] The coal mining and utilization process in my country generates approximately 6.88 × 10⁻⁶ tons of coal waste annually. 9 m 3 Mine water, as an important unconventional water resource, has a utilization rate of less than 50%. Achieving "zero discharge" of mine water and coal chemical wastewater has become a mandatory requirement in the industry. Against this backdrop, membrane concentration technology is widely used as a key link in improving water resource recovery rates. During the membrane concentration process, the supersaturation of slightly soluble inorganic salts such as calcium and magnesium in mine water gradually increases, and some organic matter accumulates, making it extremely easy for scale to form on the surface of the membrane element, clogging the micropore channels. To protect the membrane element from scaling and clogging, scale inhibitors must be added. These scale inhibitors are intercepted and enriched by the membrane with the water flow, and ultimately coexist with high concentrations of calcium and magnesium ions in the membrane concentrate. In the subsequent fluidized bed crystallization treatment of the concentrate, traditional fluidized bed crystallization technology uses sodium carbonate as a reagent and garnet as an inert carrier to induce calcium ions to form calcium carbonate crystals on the carrier, thereby removing hardness from the water. However, at this time, the scale inhibitor in the wastewater will be strongly adsorbed on the surface of the crystal carrier and the growth points of calcium carbonate crystal lattice, which will severely inhibit the nucleation and crystal growth of the crystallization process. This will cause the hardening removal efficiency of the traditional fluidized bed system with sodium carbonate as the agent to drop sharply or even become completely ineffective, and will not be able to provide qualified influent for the subsequent zero-discharge process.

[0003] Therefore, developing a technology that can efficiently treat membrane concentrate and mine water is not only for achieving the environmental protection requirement of zero emissions, but its deeper value lies in opening up a stable second water source for mining areas. The treated high-quality water can be directly used for "production reuse" (such as coal washing, dust reduction, and plant circulation cooling) and even "ecological water replenishment", completely reversing the current situation of mine water as a burden and transforming it into a valuable strategic resource. This is of great significance for alleviating the contradiction of water shortage in coal-rich and water-poor areas in western my country. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defects and shortcomings of the existing fluidized bed crystallization technology in treating wastewater containing scale inhibitors, where the scale inhibitor inhibits crystallization and causes softening failure. The present invention provides a fluidized bed wastewater treatment method that can catalyze the oxidation of peroxybicarbonate (PMC, also known as peroxymonocarbonate) or percarbonate (SPC, also known as peroxycarbonate) to provide free radicals to eliminate scale inhibitors and degrade organic matter, and can also crystallize calcium carbonate to remove hardness.

[0005] Another object of the present invention is to provide a fluidized bed wastewater treatment system.

[0006] The above-mentioned objective of this invention is achieved through the following technical solution:

[0007] A fluidized bed wastewater treatment method includes the following steps:

[0008] To obtain the calcium ion concentration in the wastewater;

[0009] A catalyst is added to the fluidized bed reactor, and peroxybicarbonate or percarbonate is added to react with the wastewater.

[0010] The molar ratio of peroxybicarbonate or percarbonate to calcium ions is (1~1.5):1;

[0011] The wastewater contains a scale inhibitor with a concentration of less than or equal to 50 mg / L.

[0012] The wastewater contains Ca 2+ The concentration meter indicates a calcium ion concentration of less than or equal to 500 mg / L.

[0013] The total hardness of the wastewater, based on the mass of CaCO3, is less than or equal to 1000 mg / L;

[0014] The organic matter concentration in the wastewater, calculated as COD, is less than or equal to 200 mg / L;

[0015] The catalyst comprises a support and an active component, wherein the active component is Co3O4 and / or CuO, and the loading of the active component is 1-5 wt%.

[0016] peroxybicarbonate (i.e., HCO4) - PMC (Proteinized Carbonate), abbreviated as PMC, is a highly oxidizing and rapidly reacting source of peroxides. The carbon-oxygen-oxygen (COO) peroxide bond in its molecular structure is easily activated by catalysis, simultaneously providing carbonate (CO3-) ions. 2- ) Induced calcium ion crystallization and highly reactive free radical precursor (HCO4) - This invention generates highly efficient free radicals to degrade scale inhibitors and remove organic matter. However, PMC itself has limited oxidation capacity. By activating the catalyst of this invention, free radicals sufficient to degrade scale inhibitors can be generated efficiently.

[0017] The catalyst described in this invention is a multifunctional catalyst that combines physical crystallization sites and chemical catalytic sites. It can provide catalytic sites to promote the oxidation of peroxybicarbonate, provide free radicals to eliminate scale inhibitors in water, degrade organic matter in water, and also provide crystallization sites to induce calcium carbonate crystallization in water.

[0018] The specific principle is as follows: PMC comes into contact with the catalytic sites (Co3O4 / CuO) on the surface of the catalyst in a fluidized state, and is efficiently catalyzed and decomposed to generate a large number of hydroxyl radicals (·OH). These highly active free radicals rapidly attack and decompose the scale inhibitor molecules in the wastewater, destroy their crystallization inhibition function, and degrade the coexisting organic pollutants at the same time.

[0019] While the scale inhibitor's inhibitory effect is broken, the carbonate ions (CO3-) produced by the decomposition of PMC... 2- ) and calcium ions (Ca) in wastewater 2+ They combine on the abundant crystallization sites on the carrier surface to form calcium carbonate crystals and gradually grow.

[0020] Percarbonate (SPC) has similar effects to peroxybicarbonate (PMC).

[0021] Therefore, the fluidized bed wastewater treatment method of the present invention can effectively eliminate the inhibition of the crystallization process by scale inhibitors and simultaneously achieve deep hardening removal and organic matter degradation, thereby overcoming the technical bottleneck of resource recycling of high-hardness wastewater containing scale inhibitors.

[0022] In a specific implementation, the amount of catalyst filling in the fluidized bed is controlled to be 10%-30% of the effective volume of the reactor, with the optimum being 15%-25%.

[0023] Preferably, the wastewater contains a scale inhibitor at a concentration of 1-50 mg / L;

[0024] The wastewater contains Ca 2+ The concentration meter shows calcium ion concentrations of 50-500 mg / L.

[0025] The total hardness of the wastewater, based on the mass of CaCO3, is 100-1000 mg / L;

[0026] The wastewater contains 10-200 mg / L of organic matter, calculated as COD.

[0027] Preferably, the peroxybicarbonate is obtained by reacting a solution containing bicarbonate with hydrogen peroxide.

[0028] Preferably, the support in the catalyst is garnet.

[0029] Preferably, the active components are Co3O4 and CuO, and the molar ratio of Co to Cu is 1:(0.5~2).

[0030] Preferably, the method for preparing the catalyst includes the following steps:

[0031] The catalyst is obtained by impregnating the garnet support in copper and / or cobalt salts, aging and drying it, and then calcining it in air at 350-450°C for 3-4 hours.

[0032] The catalyst preparation method of the present invention uses garnet particles as the core, and the surface of the particles is loaded with cobalt / copper active species through impregnation-calcination method.

[0033] Preferably, the scale inhibitor is one or more of organophosphorus scale inhibitors, polyacrylic acid scale inhibitors, or polysulfonic acid scale inhibitors.

[0034] The organophosphorus scale inhibitor is aminotrimethylene phosphonic acid (ATMP) or hydroxyethylidene diphosphonic acid (HEDP).

[0035] The polyacrylic scale inhibitor is polyacrylic acid (PAA), polymaleic anhydride (HPMA), or acrylate-hydroxypropyl acrylate copolymer.

[0036] The polysulfonic acid scale inhibitor is a homopolymer or copolymer of sodium polystyrene sulfonate (PSS) or 2-acrylamide-2-methylpropanesulfonic acid (AMPS).

[0037] In specific implementations, when the scale inhibitor in the water is an organophosphorus scale inhibitor, or when the water contains complex organic pollutants such as benzene compounds and phenols found in coal chemical wastewater, a catalyst with Co3O4 as the active component can be used. This is because Co3O4 has excellent catalytic activity and can efficiently activate PMC to generate a large number of hydroxyl radicals (·OH). Therefore, when the wastewater has a COD > 80 mg / L or contains high levels of organic matter and high toxicity, such as recalcitrant organic matter, cobalt-based catalysts are preferred.

[0038] In specific implementations, when the scale inhibitor in the water is a polymer scale inhibitor such as polyacrylic acid or polysulfonic acid, a catalyst with CuO as the active component can be used. This is because the catalyst with CuO as the active component has mild catalytic activity and offers the best cost-effectiveness in scenarios where the organic matter concentration (COD in the range of 30-80 mg / L) is not extremely high. It is suitable for medium-to-low concentration wastewater where scale inhibition is the primary method and the organic matter concentration is moderate.

[0039] In specific implementations, when the scale inhibitor in the water is an organophosphorus scale inhibitor or a polymer scale inhibitor such as polyacrylic acid or polysulfonic acid, a catalyst with active components of Co3O4 and CuO can be used. This utilizes the synergistic catalytic effect produced by the bimetallic system. + / Co² + With Cu² + / Cu +A redox cycle can be formed, significantly improving electron transfer rate and free radical yield. It combines the strong oxidizing power of cobalt-based catalysts with the economic efficiency of copper-based catalysts, exhibiting stable and efficient removal of mixed scale inhibitors (containing both organophosphorus and polymers) and a wide range of organic concentrations. It is the preferred solution for treating membrane concentrates with unclear water quality or complex mine water. It performs best in handling highly challenging wastewater with complex composition and large fluctuations in water quality.

[0040] Preferably, the wastewater is reverse osmosis membrane concentrate, mine water, or industrial wastewater containing scale inhibitors.

[0041] Preferably, the surface flow velocity of the water is 2-5 m / h, and the empty bed contact time (EBCT) is 10-15 min. This ensures that the bed is in a uniform fluidized state.

[0042] Preferably, the organic compound is a benzene-based organic compound and / or a phenolic organic compound.

[0043] This invention also protects a fluidized bed wastewater treatment system applicable to any of the fluidized bed wastewater treatment methods described above. The fluidized bed wastewater treatment system includes a fluidized bed reactor containing the catalyst and a reagent dosing device connected to the fluidized bed reactor. The reagent dosing device is a peroxybicarbonate reagent dosing device and / or a percarbonate reagent dosing device.

[0044] Compared with the prior art, the beneficial effects of the present invention are:

[0045] This invention discloses a fluidized bed wastewater treatment method, comprising the following steps: obtaining the calcium ion concentration in the water body, adding a catalyst to the fluidized bed reactor, and adding peroxybicarbonate or percarbonate to react with the wastewater. This invention targets complex wastewater with high hardness, containing scale inhibitors and organic matter. It employs a transition metal oxide catalyst loaded with cobalt and / or copper, using peroxybicarbonate or percarbonate as the core reactant. Within a single fluidized bed reactor, it simultaneously achieves three synergistic functions: "eliminating the scale inhibitor effect (scale removal)," "degrading organic matter (degradation)," and "inducing calcium carbonate crystallization for hardness removal (crystallization)." This solves the industry problem of traditional fluidized bed crystallization technology, which struggles to deeply remove hardness ions from scale inhibitors. It also achieves synergistic removal of organic matter, providing an efficient and economical integrated solution for the deep softening and resource recovery of complex wastewater such as membrane concentrates and mine water. It offers a complete and economical solution for resource recovery (such as high-standard industrial water and ecological water replenishment), completely transforming environmental burden into a valuable strategic resource. This is of great significance for alleviating water resource conflicts in coal-rich and water-scarce regions. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the device in the embodiment.

[0047] In the diagram, 1-fluidized bed reactor, 2-carrier bed, 3-raw water inlet, 4-reagent dosing port, 5-circulating liquid outlet, 6-circulating return water inlet, 7-purified water outlet, 8-raw water inlet booster pump, 9-reagent dosing pump, 10-circulating pump, 11-reagent storage tank, 12-raw water storage tank, 13-raw water inlet pipe, 14-reagent dosing pipe, 15-circulating pipe, 16-purified water outlet pipe. Detailed Implementation

[0048] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0049] Sodium percarbonate (2Na2CO3·3H2O2), CAS number 15630-89-4.

[0050] Scale inhibitor 1, organophosphorus scale inhibitor, aminotrimethylenephosphonic acid (ATMP, industrial grade, content ≥50%), purchased from Shandong Taihe Water Treatment Technology Co., Ltd., brand name TH. ATMP.

[0051] Scale inhibitor 2 is a mixture of polyacrylic acid (PAA, Mw≈2000) and sodium polystyrene sulfonate (PSS, Mw≈70000) in a 1:1 mass ratio. PAA was purchased from Aladdin Reagents, brand name P110926; PSS was purchased from Sigma. Aldrich, 434574.

[0052] Organic compounds: Benzene (analytical grade, Sinopharm Group) and phenol (analytical grade, Sinopharm Group) are mixed in a mass ratio of 1:1.

[0053] Water Quality 1: Scale Inhibitor: ATMP, concentration 50 mg / L (based on active ingredient). Calcium ions (Ca²⁺) + Concentration: 500 mg / L. Total hardness (as CaCO3): 1000 mg / L. COD: 200 mg / L. pH: 7.5. Temperature: 25°C.

[0054] Water Quality 2: Scale Inhibitor: A 1:1 mixture of PAA and PSS scale inhibitor, with a total concentration of 50 mg / L (based on active ingredient). Calcium ions (Ca²⁺) + Concentration: 300 mg / L. Total hardness (as CaCO3): 750 mg / L. COD: 70 mg / L. pH: 8.0. Temperature: 25°C.

[0055] Water Quality 3: Scale Inhibitor: ATMP and PAA / PSS mixed scale inhibitor are mixed at a mass ratio of 1:1, with a total concentration of 50 mg / L (based on active ingredient). Calcium ions (Ca²⁺) + Concentration: 400 mg / L. Total hardness (as CaCO3): 1000 mg / L. COD: 120 mg / L. pH: 8.5. Temperature: 25°C.

[0056] Catalyst 1 comprises a support and an active component. The active component is Co3O4, and the support is garnet. The loading of the active component is 2 wt%. The preparation method of catalyst 1 is as follows: Co(NO3)2·6H2O is accurately weighed and prepared into an impregnation solution with deionized water at a concentration of 0.01 mol / L. The impregnation solution is uniformly loaded onto the pretreated garnet support using an equal-volume impregnation method. The impregnated material is aged at room temperature for 6-12 hours, followed by drying at 80-120°C for 4-8 hours. Finally, the dried sample is placed in a muffle furnace and calcined in a static air atmosphere at 400-450°C for 3-4 hours. After natural cooling, catalyst 1 is obtained.

[0057] Catalyst 2 comprises a support and an active component. The active component is CuO, and the support is garnet. The loading of the active component is 2 wt%. The preparation method of catalyst 2 is as follows: Cu(NO3)2·3H2O is accurately weighed and prepared into an impregnation solution with a concentration of 0.15 mol / L using deionized water. The impregnation solution is loaded onto a pretreated garnet support using an equal-volume impregnation method. After aging at room temperature for 6-12 hours, drying at 80-120°C for 4-8 hours, and calcining in air at 350-400°C for 3-4 hours, catalyst 2 is obtained.

[0058] Catalyst 3 comprises a support and active components. The active components are Co3O4 and CuO, and the support is garnet. The loading of the active components is 2 wt%, and the Co:Cu molar ratio is 1:1. The preparation method of catalyst 3 is as follows: Co(NO3)2·6H2O and Cu(NO3)2·3H2O are accurately weighed according to the Co:Cu molar ratio of 1:1 and dissolved together in deionized water to prepare a mixed impregnation solution with a total metal ion concentration of 0.2 mol / L. The solution is then loaded onto the garnet support using an equal-volume impregnation method. After impregnation, the material is aged at room temperature for 6-12 hours, dried at 80-120°C for 4-8 hours, and then calcined in air at 400-450°C for 4 hours to obtain catalyst 3.

[0059] Catalyst 4 comprises a support and active components. The active components are Co3O4 and CuO, the support is garnet, the loading of the active components is 1 wt%, and the Co:Cu molar ratio is 1:1. The preparation method of catalyst 4 differs from that of catalyst 3 in that a mixed impregnation solution with a total metal ion concentration of 0.1 mol / L is prepared.

[0060] Catalyst 5 comprises a support and active components. The active components are Co3O4 and CuO, the support is garnet, the loading of the active components is 3 wt%, and the Co:Cu molar ratio is 1:1. The difference between the preparation method of catalyst 5 and catalyst 3 is that a mixed impregnation solution with a total metal ion concentration of 0.3 mol / L is prepared.

[0061] Catalyst 6 comprises a support and active components. The active components are Co3O4 and CuO, the support is garnet, the loading of the active components is 5 wt%, and the Co:Cu molar ratio is 1:1. The preparation method of catalyst 6 differs from that of catalyst 3 in that a mixed impregnation solution with a total metal ion concentration of 0.5 mol / L is prepared.

[0062] Catalyst 7 comprises a support and active components. The active components are Co3O4 and CuO, the support is garnet, the loading of the active components is 2wt%, and the Co:Cu molar ratio is 2:1. The preparation method of catalyst 7 differs from that of catalyst 3 in that Co(NO3)2·6H2O and Cu(NO3)2·3H2O are precisely weighed according to the Co:Cu molar ratio of 2:1.

[0063] Catalyst 8 comprises a support and active components. The active components are Co3O4 and CuO, the support is garnet, the loading of the active components is 2wt%, and the Co:Cu molar ratio is 1:2. The preparation method of catalyst 8 differs from that of catalyst 3 in that Co(NO3)2·6H2O and Cu(NO3)2·3H2O are precisely weighed according to the Co:Cu molar ratio of 1:2.

[0064] The catalyst loading was obtained by ICP-OES.

[0065] Experimental System: All embodiments used a laboratory-scale continuous fluidized bed reactor. The reactor body consisted of a fluidized bed with an inner diameter of 30 mm and a total height of approximately 1200 mm. The catalyst was wet-packed into the column at a volume of 280 mL, corresponding to an initial fixed bed height of approximately 400 mm. Raw water and either PMC or SPC solution were continuously pumped to the bottom of the reactor at predetermined ratios using two independent metering pump systems. The surface flow rate was controlled at approximately 2.4 m / h.

[0066] Example 1

[0067] A fluidized bed wastewater treatment method includes the following steps:

[0068] Using simulated influent water quality 1 as the raw water, the calcium ion concentration in the wastewater was found to be 12.5 mM.

[0069] Catalyst 1 was added to the fluidized bed reactor at a loading volume of 280 mL.

[0070] The raw water and percarbonate solution are continuously transported to the reactor inlet by a metering pump system for mixing, so that the percarbonate reacts with the wastewater.

[0071] The raw water inlet flow rate is 28 mL / min.

[0072] Peroxybicarbonate is obtained by reacting sodium bicarbonate with hydrogen peroxide.

[0073] The concentration of peroxybicarbonate is 12.5 mM, which means the molar ratio of peroxybicarbonate to calcium ions is 1:1.

[0074] The surface flow rate is 2.4 m / h.

[0075] The empty bed contact time (EBCT) is 10 minutes.

[0076] After the system has been running stably for 30 minutes, a sample is taken from the outlet for testing.

[0077] A fluidized bed wastewater treatment system is provided, applicable to the above-mentioned fluidized bed wastewater treatment method. The fluidized bed wastewater treatment system includes a fluidized bed reactor 1 containing a catalyst and a reagent dosing device connected to the fluidized bed reactor 1. The reagent dosing device is a PMC reagent dosing device and / or an SPC reagent dosing device.

[0078] More specifically, the fluidized bed wastewater treatment system includes a raw water inlet booster pump 8, a fluidized bed reactor 1, and a reagent dosing device. The inlet end of the raw water inlet booster pump 8 is connected to the raw water storage tank 12, and the outlet end of the raw water inlet booster pump 8 is connected to the raw water inlet 3 of the fluidized bed reactor 1 through a raw water inlet pipe 13.

[0079] The bottom of the fluidized bed reactor 1 is provided with a reagent inlet 4. The reagent dosing device includes a reagent storage tank 11, a reagent dosing pipeline 14 and a reagent dosing pump 9. The reagent dosing pump 9 is installed on the reagent dosing pipeline 14. The reagent dosing inlet 4 is connected to the reagent storage tank 11 through the reagent dosing pipeline 14.

[0080] The fluidized bed reactor 1 is equipped with a catalyst-supported bed 2;

[0081] The fluidized bed reactor 1 is provided with a circulation return port 6 at the bottom and a circulation liquid extraction port 5 in the middle. A circulation pipe 15 is provided between the circulation return port 6 and the circulation liquid extraction port 5, and a circulation pump 10 is provided on the circulation pipe 15.

[0082] The upper part of the fluidized bed reactor 1 is provided with a purified water outlet 7 and a purified water outlet pipe 16 connected to the purified water outlet 7.

[0083] The operation method of the above system includes the following process:

[0084] S1. Carrier filling and water injection: The catalyst is filled into the fluidized bed reactor 1 to form a carrier bed 2. Raw water from the raw water storage tank 12 is injected into the raw water inlet 3 of the fluidized bed reactor 1 through the raw water inlet pump 8 on the raw water inlet pipe 13, so that the water level at least covers the circulating liquid outlet 5 and soaks the carrier bed 2.

[0085] S2. Establishing a fluidized state: Start the circulation pump 10. This pump draws water from the circulating liquid outlet 5, which is already filled with liquid, pressurizes it, and then pumps it back to the bottom of the fluidized bed reactor 1 through the circulation pipe 15 and the circulation return port 6. By adjusting the power of the circulation pump 10, an upward water flow is formed inside the reactor, causing the carrier bed 2 to gradually enter a uniform and vigorous fluidized state.

[0086] S3. Add reagents and start continuous treatment: After the fluidized bed is stabilized, perform the following operations simultaneously: Start the reagent dosing pump 9 to continuously and accurately inject the reagents from the reagent storage tank 11 into the reagent dosing port 4 through the reagent dosing pipe 14. Keep the circulation pump 10 running and start (or keep) the raw water inlet lift pump 8 to continuously pump the wastewater to be treated into the raw water inlet 3 at the set treatment flow rate.

[0087] S4. Mixing and Reaction: The continuously introduced raw water, reagents, and powerful circulating water flow are thoroughly mixed at the bottom of the fluidized bed reactor 1. As the mixture rises, it passes through the carrier bed 2, which is in a state of vigorous fluidization.

[0088] S5. Effluent and Balance: The treated clean water rises to the top of the reactor and flows out continuously from the purified water outlet 7 through the purified water outlet pipe 16, so that the system achieves a dynamic balance between influent, reaction and effluent.

[0089] S6. Maintenance and Slag Removal: Circulation pump 10 operates continuously to maintain the fluidization state of the bed and the intensity of internal circulation. Calcium carbonate crystals that have grown to a certain particle size can be periodically removed from the system.

[0090] Example 2

[0091] A fluidized bed wastewater treatment method

[0092] The difference from Example 1 is that catalyst 1 is replaced with catalyst 2.

[0093] Example 3

[0094] A fluidized bed wastewater treatment method

[0095] The difference from Example 1 is that catalyst 1 is replaced with catalyst 3.

[0096] Example 4

[0097] A fluidized bed wastewater treatment method

[0098] The difference from Example 1 is that water quality 1 is replaced with water quality 2.

[0099] The concentration of PMC is 7.5 mM, which means that the molar ratio of PMC to calcium ions is 1:1.

[0100] Example 5

[0101] A fluidized bed wastewater treatment method

[0102] The difference from Example 4 is that catalyst 1 is replaced with catalyst 2.

[0103] Example 6

[0104] A fluidized bed wastewater treatment method

[0105] The difference from Example 4 is that catalyst 1 is replaced with catalyst 3.

[0106] Example 7

[0107] A fluidized bed wastewater treatment method

[0108] The difference from Example 1 is that water quality 1 is replaced with water quality 3.

[0109] The concentration of PMC is 10 mM, which means that the molar ratio of PMC to calcium ions is 1:1.

[0110] Example 8

[0111] A fluidized bed wastewater treatment method

[0112] The difference from Example 7 is that catalyst 1 is replaced with catalyst 2.

[0113] Example 9

[0114] A fluidized bed wastewater treatment method

[0115] The difference from Example 7 is that catalyst 1 is replaced with catalyst 3.

[0116] Example 10

[0117] A fluidized bed wastewater treatment method

[0118] The difference from Example 1 is that sodium percarbonate is used instead of peroxybicarbonate.

[0119] Example 11

[0120] A fluidized bed wastewater treatment method

[0121] The difference from Example 9 is that catalyst 3 is replaced with catalyst 4.

[0122] Example 12

[0123] A fluidized bed wastewater treatment method

[0124] The difference from Example 9 is that catalyst 3 is replaced with catalyst 5.

[0125] Example 13

[0126] A fluidized bed wastewater treatment method

[0127] The difference from Example 9 is that catalyst 3 is replaced with catalyst 6.

[0128] Example 14

[0129] A fluidized bed wastewater treatment method

[0130] The difference from Example 9 is that catalyst 3 is replaced with catalyst 7.

[0131] Example 15

[0132] A fluidized bed wastewater treatment method

[0133] The difference from Example 9 is that catalyst 3 is replaced with catalyst 8.

[0134] Comparative Example 1

[0135] A fluidized bed wastewater treatment method:

[0136] The difference from Example 1 is that no catalyst was added, and the column was empty.

[0137] Comparative Example 2

[0138] A fluidized bed wastewater treatment method:

[0139] The difference from Example 1 is that catalyst 1 is replaced with garnet particles.

[0140] Comparative Example 3

[0141] A fluidized bed wastewater treatment method:

[0142] The difference from Example 1 is that the PMC agent is replaced with a conventional sodium carbonate (Na2CO3) solution with equimolar carbonate ions.

[0143] In all embodiments and comparative examples, samples were taken and the calcium ion concentration and COD content were measured 30 minutes after the system had been running stably. The calcium ion removal rate and COD removal rate are shown in Table 1 below.

[0144] Table 1

[0145]

[0146] As shown in the table above, in Comparative Examples 1-3, the removal rates of calcium ions and COD were both below 16%, proving that PMC or traditional crystallization processes alone cannot overcome the inhibition of scale inhibitors. However, this invention, through a synergistic system of "PMC / SPC + modified catalyst," achieves highly efficient simultaneous removal of calcium ions (88.2%~98.2%) and COD (80.4%~97%), verifying the effectiveness of the "anti-inhibition-degradation-crystallization" triple synergistic mechanism.

[0147] Examples 1-3 show that for water quality 1 with high organic matter and containing organophosphorus compounds, the Co3O4-based catalyst exhibits the strongest oxidation capacity, while the bimetallic catalyst demonstrates outstanding overall performance. Examples 4-6 show that for water quality 2 with moderate organic matter and polymer scale inhibitors, the CuO-based catalyst is equally effective and more economical. Examples 7-9 show that for water quality 3 with complex mixtures, the bimetallic catalyst exhibits the best synergistic stability and treatment efficiency. Examples 1 and 10 show that SPC, as an alternative agent, is also effective in treating high-hardness wastewater containing scale inhibitors. Examples 11-15 show that the bimetallic catalyst exhibits the best synergistic effect when the total loading is approximately 2 wt% and the cobalt-copper molar ratio is 1:1; higher loadings will cover the crystallization sites of the support, resulting in a slight decrease in calcium ion removal rate.

[0148] In summary, this invention, through the targeted design and synergistic effect of catalysts and PMC / SPC agents, successfully solves the problems of limited hardness removal and organic matter accumulation in high-hardness wastewater containing scale inhibitors, providing an efficient and flexible integrated solution for the deep softening and resource utilization of complex wastewater.

[0149] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A fluidized bed wastewater treatment method, characterized in that, Includes the following steps: To obtain the calcium ion concentration in the wastewater; A catalyst is added to a fluidized bed reactor, and peroxybicarbonate or percarbonate is added to react with the wastewater to degrade the scale inhibitor in the wastewater, remove organic matter in the wastewater, and generate CaCO3 crystals. The molar ratio of peroxybicarbonate or percarbonate to calcium ions is (1~1.5):1; The wastewater contains a scale inhibitor at a concentration of 1-50 mg / L; The wastewater contains Ca 2+ The concentration meter shows calcium ion concentrations of 50-500 mg / L. The total hardness of the wastewater, based on the mass of CaCO3, is 100-1000 mg / L; The wastewater, calculated as COD, has an organic matter concentration of 10-200 mg / L; The catalyst comprises a support and an active component, wherein the active component is Co3O4 and / or CuO, and the loading of the active component is 1-5 wt%. The catalyst is supported by garnet.

2. The method as described in claim 1, characterized in that, The peroxybicarbonate is obtained by reacting a solution containing bicarbonate with hydrogen peroxide.

3. The method as described in claim 1, characterized in that, The active components are Co3O4 and CuO, with a molar ratio of Co to Cu of 1:(0.5~2).

4. The method as described in claim 1, characterized in that, The preparation method of the catalyst includes the following steps: impregnating the garnet support in copper salt and / or cobalt salt, aging and drying it, and then calcining it in air at 350-450°C for 3-4 hours to obtain the catalyst.

5. The method as described in claim 1, characterized in that, The scale inhibitor is one or more of organophosphorus scale inhibitors, polyacrylic acid scale inhibitors, or polysulfonic acid scale inhibitors.

6. The method as described in claim 1, characterized in that, The wastewater is reverse osmosis membrane concentrate, mine water, or industrial wastewater containing scale inhibitors.

7. The method as described in claim 1, characterized in that, The surface flow velocity of the water body is 2-5 m / h, and the contact time with the empty bed is 10-15 min.

8. The method as described in claim 1, characterized in that, The organic compound is a benzene-based organic compound.

Images