A high-hardness micro-polluted water synchronous purification system and purification method

Abstract

The present application relates to a kind of high hardness micro-polluted water synchronous purification system and purification method.The present application includes total inlet pipe, for providing high hardness micro-polluted water;Hardness removal synchronous catalytic oxidation unit, in communication with total inlet pipe, hardness removal synchronous catalytic oxidation unit is provided with main inlet, mixed push flow ware, micro-nano bubble secondary cutter, effluent overflow tank;Calcium hydroxide storage pool, for providing calcium hydroxide solution;Gas-liquid synchronous pressurizing pump and ozone generator, ozone generator is in communication with the gas inlet end of gas-liquid synchronous pressurizing pump, the water inlet end of gas-liquid synchronous pressurizing pump is in communication with total inlet pipe, the water outlet end of gas-liquid synchronous pressurizing pump is in communication with micro-nano bubble secondary cutter;Induced crystallization filter unit, is provided with induced crystallization filter material;Alkaline back adjustment unit, is provided with adjust alkali mixed push flow ware and carbon dioxide aeration disc;Carbon dioxide generator, in communication with alkaline back adjustment unit.The present application can remove the problem of hardness and trace organic pollutants simultaneously at low cost and safely.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and in particular to a simultaneous purification system and method for high-hardness, slightly polluted water. Background Technology

[0002] Traditional drinking water purification processes typically involve coagulation, sedimentation, filtration, and disinfection. These traditional processes are ineffective at removing hardness from drinking water sources. For high-hardness drinking water sources, simple traditional treatments result in poor taste and severe scaling and water stains during use. Currently, with the development of the organic chemical industry, various organic pollutants are gradually spreading to water sources. These organic pollutants in water sources are characterized by low concentrations, diverse types, and difficulty in degradation, resulting in slightly polluted water. However, traditional drinking water purification processes cannot effectively remove trace amounts of organic pollutants from water sources. Therefore, an increasing number of water treatment scenarios face the need to simultaneously remove hardness and organic pollutants, but currently, there is a lack of safe and economical processes for simultaneously removing hardness and organic pollutants from drinking water.

[0003] Hardness removal in water can generally be achieved through chemical precipitation using calcium hydroxide, but this only specifically removes carbonate hardness. Removing organic pollutants from slightly polluted water typically employs processes such as adsorption and coagulation separation, membrane filtration, and advanced oxidation. However, the adsorbents used in adsorption and coagulation separation processes in water treatment can introduce safety risks; membrane filtration is costly and generates high-concentration wastewater, posing significant disposal challenges; advanced oxidation processes using strong oxidants still introduce safety risks; and ozone advanced oxidation processes, while adding catalysts, also introduce safety risks, but without catalysts, ozone oxidation capacity is insufficient to effectively remove organic pollutants. Existing processes rarely offer a simple and low-cost way to simultaneously remove hardness and organic pollutants. Therefore, there is an urgent need for a simultaneous purification system for high-hardness, slightly polluted water to remove both hardness and organic pollutants from drinking water. Summary of the Invention

[0004] Therefore, the technical problem to be solved by this invention is to overcome the difficulty in simultaneously removing hardness and trace organic pollutants in drinking water treatment processes at low cost and safely, and to provide a simultaneous purification system and method for high-hardness, slightly polluted water. This system and method can couple calcium hydroxide hardening, in-situ catalytic ozone oxidation of calcium carbonate microcrystals, calcite-induced crystallization filtration, and carbon dioxide pH adjustment to form a safe, economical, and compact simultaneous purification process.

[0005] To solve the above-mentioned technical problems, the present invention provides a high-hardness, slightly polluted water simultaneous purification system, comprising: The main inlet pipe is used to supply high-hardness, slightly polluted water. The hardening synchronous catalytic oxidation unit is connected to the main water inlet pipe. The hardening synchronous catalytic oxidation unit is equipped with a main water inlet, a mixing flow promoter, a micro-nano bubble secondary cutter, and a water outlet overflow tank. The main water inlet pipe is connected to the main water inlet. A calcium hydroxide storage tank is used to supply calcium hydroxide solution to the hardening synchronous catalytic oxidation unit; A gas-liquid synchronous pressurizing pump and an ozone generator are connected. The ozone generator is connected to the air inlet of the gas-liquid synchronous pressurizing pump, the water inlet of the gas-liquid synchronous pressurizing pump is connected to the main water inlet pipe, and the water outlet of the gas-liquid synchronous pressurizing pump is connected to the micro-nano bubble secondary cutter. Ozone and some raw water can be pressurized and dissolved in the gas-liquid synchronous pressurizing pump to form dissolved air water, and released at the micro-nano bubble secondary cutter to form ozone micro-nano bubbles. An induced crystallization filtration unit is provided with induced crystallization filter media, and the inlet of the induced crystallization filtration unit is connected to the outlet overflow tank; The alkaline adjustment unit is connected to the outlet of the induced crystallization filtration unit, and the alkaline adjustment unit is equipped with an alkali-adjusting mixing flow promoter and a carbon dioxide aeration disc. A carbon dioxide generator is connected to the alkaline adjustment unit; wherein, the carbon dioxide provided by the carbon dioxide generator can enter the alkaline adjustment unit through the carbon dioxide aeration disc, and dissolve in the water under the action of the alkalinity-adjusting mixing and propulsion device to adjust the pH of the water.

[0006] In one embodiment of the present invention, the bottom sidewall of the hardness removal synchronous catalytic oxidation unit is provided with a main water inlet communicating with the main water inlet pipe, the mixing flow generator is located in the middle of the hardness removal synchronous catalytic oxidation unit, the micro-nano bubble secondary cutter is located at the bottom of the hardness removal synchronous catalytic oxidation unit, and the water overflow trough is located on the upper sidewall of the hardness removal synchronous catalytic oxidation unit.

[0007] In one embodiment of the present invention, an ozone exhaust gas destroyer is also provided on the top of the hardening synchronous catalytic oxidation unit.

[0008] In one embodiment of the present invention, the induced crystallization filtration unit includes a filter tank inlet pipe, a filter media support plate, and a sludge discharge valve. The filter tank inlet pipe is connected to the outlet overflow trough. The filter media support plate is disposed inside the induced crystallization filtration unit and is used to support the induced crystallization filter media. The sludge discharge valve is disposed at the bottom of the induced crystallization filtration unit, and the outlet is disposed on the upper side wall of the induced crystallization filtration unit.

[0009] In one embodiment of the present invention, the induced crystallization filter material is a flaky calcite filter material, the size of which is 10 mm to 20 mm and the thickness is less than 10 mm.

[0010] In one embodiment of the present invention, a dosing pump, a dosing pump inlet pipe, and a dosing pump outlet pipe are also included. The calcium hydroxide storage tank is connected to the dosing pump through the dosing pump inlet pipe, and the calcium hydroxide storage tank is fed into the hardness removal synchronous catalytic oxidation unit through the dosing pump outlet pipe.

[0011] In one embodiment of the present invention, the alkaline adjustment unit includes an alkali-adjusting inlet pipe and an end outlet. The alkali-adjusting inlet pipe is connected to the outlet of the induced crystallization filter unit. The carbon dioxide aeration disc is disposed at the bottom of the alkaline adjustment unit, and the end outlet is disposed on the upper side wall of the alkaline adjustment unit.

[0012] In one embodiment of the present invention, the gas-liquid synchronous pressurization pump is connected to the ozone generator through the mixing pump inlet pipe, connected to the main water inlet pipe through the mixing pump water inlet pipe, and connected to the micro-nano bubble secondary cutter through the dissolved air water pipe, so that ozone and part of the raw water are pressurized and dissolved in the gas-liquid synchronous pressurization pump to form dissolved air water, and released at the micro-nano bubble secondary cutter to form ozone micro-nano bubbles.

[0013] In one embodiment of the present invention, the carbon dioxide generator is connected to the carbon dioxide pressurizing pump through a carbon dioxide inlet pipe, and the carbon dioxide pressurizing pump is connected to the carbon dioxide aeration disc through a carbon dioxide outlet pipe; the carbon dioxide generator is an air compression and separation device, and the oxygen generated by the air compression and separation device in sync is supplied to the ozone generator.

[0014] This invention also provides a method for simultaneous purification of high-hardness, slightly polluted water, employing the aforementioned simultaneous purification system for high-hardness, slightly polluted water. The purification method includes the following steps: High-hardness, slightly polluted water is introduced into the simultaneous hardness removal and catalytic oxidation unit through the main inlet pipe. Calcium hydroxide solution is added into the simultaneous hardness removal and catalytic oxidation unit through the calcium hydroxide storage tank. Under the mixing action of the mixing and flow booster, the high-hardness, slightly polluted water reacts with calcium hydroxide to generate calcium carbonate microcrystalline precipitate. The gas-liquid synchronous pressurization pump draws part of the raw water from the main water inlet pipe, draws ozone gas from the ozone generation unit, and pressurizes and dissolves the ozone gas in the gas-liquid synchronous pressurization pump. The dissolved gas water is transported to the micro-nano bubble secondary cutter for release to form ozone micro-nano bubbles. Under the action of the mixing and flow propulsion device, the ozone micro-bubbles come into contact with the calcium carbonate microcrystalline precipitate, and are excited to generate hydroxyl radicals to oxidize and remove the recalcitrant trace organic pollutants in the water. Some calcium carbonate crystals are discharged after settling at the bottom of the hardening synchronous catalytic oxidation unit. Other calcium carbonate microcrystals that are not easy to settle enter the induced crystallization filtration unit from the overflow chute with the water flow. They are intercepted by the induced crystallization filter media and continue to grow into secondary crystals on the surface of the flaky calcite filter media. They are then fixed in the bed of the induced crystallization filter media. The sediment that settles at the bottom of the induced crystallization filtration unit due to gravity is discharged. After induced crystallization filtration, the water enters the alkaline correction unit. To adjust the pH level, carbon dioxide supplied by the carbon dioxide generator enters the alkalinity adjustment unit through the carbon dioxide aeration disc and dissolves in the water after induced crystallization filtration under the action of the alkalinity adjustment mixing and propulsion device, so as to adjust the pH level of the water to a suitable range for drinking water.

[0015] The technical solution of the present invention has the following advantages compared with the prior art: This invention combines two treatment processes—hardness removal and ozone oxidation of micro-polluting organic matter—to achieve simultaneous removal of both hardness and micro-polluting organic matter. This shortens the traditional series-connected process for removing hardness and micro-polluting organic matter and reduces the construction cost of drinking water treatment projects.

[0016] This invention uses the fine calcium carbonate precipitate generated during the hardening process as a catalyst for ozone oxidation of micro-polluting organic matter. The process enhances the oxidizing power of ozone, avoids the addition of other catalysts, and achieves enhanced ozone removal of micro-polluting organic matter in drinking water treatment processes without the use of additional catalysts. It utilizes the byproducts of hardening removal in situ, does not introduce external catalysts, and improves the economy and safety of drinking water treatment processes.

[0017] In this invention, the high alkalinity conditions during the hardening process are simultaneously used as background conditions for ozone catalytic oxidation. This increases the yield of hydroxyl radicals during the catalytic oxidation process, enhances the ability to oxidize and remove micro-polluting organic matter in water, and more thoroughly oxidizes recalcitrant organic matter in water.

[0018] This invention utilizes the excellent dispersibility of ozone micro-nano bubbles in water to achieve uniform mixing of ozone gas and fine calcium carbonate precipitate particles in the slurry layer. This improves the mass transfer and contact efficiency in the oxidation of micro-polluting organic matter, thereby enhancing the efficiency of the treatment process in removing micro-polluting organic matter. Compared with the contact oxidation method of traditional bubble aeration, the ozone usage in the catalytic oxidation technology of this invention can be significantly reduced, making it more economical.

[0019] This invention provides a calcite-induced crystallization filtration scheme, which can further precipitate and intercept calcium carbonate microcrystals present in the effluent of the hardening simultaneous catalytic oxidation unit. The calcite filter media has a calcite crystal surface, which has a natural affinity for calcium carbonate microcrystals and can attach and grow crystals. The calcite-induced crystallization filtration method can intercept and filter calcium carbonate microcrystals more efficiently.

[0020] The present invention uses carbon dioxide to adjust the pH at the end, which does not introduce other reagents. This is a safer option in drinking water treatment processes, better meets the safety requirements of drinking water treatment, and is more feasible.

[0021] Since carbon dioxide can be captured and separated from the air, oxygen in the air can be separated simultaneously during the compression separation process, providing an oxygen source for the ozone generator. This achieves two goals at once, requiring only one set of air compression separation equipment, making the process more economical. Attached Figure Description

[0022] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0023] Figure 1 This is a schematic diagram of the high-hardness, slightly polluted water simultaneous purification system of the present invention.

[0024] Explanation of reference numerals on the accompanying drawings: 1. Main water inlet pipe; 2. Hardening synchronous catalytic oxidation unit; 21. Main inlet; 22. Mixing and flow propulsion device; 23. Micro-nano bubble secondary cutter; 24. Ozone tail gas destroyer; 25. Outlet overflow tank; 26. Slurry discharge valve; 3. Induced crystallization filtration unit; 31. Filter tank inlet pipe; 32. Filter media support plate; 33. Induced crystallization filter media; 34. Sludge discharge valve; 35. Water outlet; 4. Alkalinity adjustment unit; 41. Alkalinity adjustment inlet pipe; 42. Alkalinity adjustment mixing and flow propeller; 43. Carbon dioxide aeration disc; 44. Terminal outlet; 5. Calcium hydroxide storage tank; 6. Dosing pump; 61. Dosing pump inlet pipe; 62. Dosing pump outlet pipe; 7. Ozone generator; 8. Gas-liquid synchronous booster pump; 81. Mixing pump air inlet pipe; 82. Mixing pump water inlet pipe; 83. Dissolved gas water pipe; 9. Carbon dioxide generator; 10. Carbon dioxide pressurization pump; 101. Carbon dioxide inlet pipe; 102. Carbon dioxide outlet pipe. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0026] In this invention, when directions (up, down, left, right, front, and back) are described, it is only for the convenience of describing the technical solution of this invention, and does not indicate or imply that the technical features referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0027] In this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc., are understood to exclude the stated number; "above," "below," "within," etc., are understood to include the stated number. In the description of this invention, the terms "first" and "second" are used only to distinguish technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0028] In this invention, unless otherwise explicitly defined, the terms "setting," "installing," and "connecting" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium; a fixed connection, a detachable connection, or an integrally formed connection; a mechanical connection, an electrical connection, or a connection capable of mutual communication; or the internal connection of two components or the interaction between two components. Those skilled in the art can reasonably determine the specific meaning of the above terms in this invention based on the specific content of the technical solution.

[0029] Example 1 Reference Figure 1 As shown, this embodiment provides a high-hardness, slightly polluted water simultaneous purification system, including: Main inlet pipe 1 is used to supply high-hardness, slightly polluted water; The hardening synchronous catalytic oxidation unit 2 is connected to the main water inlet pipe 1. The hardening synchronous catalytic oxidation unit 2 is equipped with a main water inlet 21, a mixing flow promoter 22, a micro-nano bubble secondary cutter 23, and a water outlet overflow tank 25; the main water inlet pipe 1 is connected to the main water inlet 21. Calcium hydroxide storage tank 5 is used to provide calcium hydroxide solution to the hardening synchronous catalytic oxidation unit 2; A gas-liquid synchronous pressurizing pump 8 and an ozone generator 7 are connected. The ozone generator 7 is connected to the air inlet of the gas-liquid synchronous pressurizing pump 8. The water inlet of the gas-liquid synchronous pressurizing pump 8 is connected to the main water inlet pipe 1. The water outlet of the gas-liquid synchronous pressurizing pump 8 is connected to the micro-nano bubble secondary cutter 23. Ozone and some raw water can be pressurized and dissolved in the gas-liquid synchronous pressurizing pump 8 to form dissolved air water, and released at the micro-nano bubble secondary cutter 23 to form ozone micro-nano bubbles. The induced crystallization filtration unit 3 is provided with induced crystallization filter media 33, and the inlet of the induced crystallization filtration unit 3 is connected to the outlet overflow tank 25. The alkaline adjustment unit 4 is connected to the outlet 35 of the induced crystallization filter unit 3. The alkaline adjustment unit 4 is equipped with an alkaline mixing and propulsion device 42 and a carbon dioxide aeration disc 43. The carbon dioxide generator 9 is connected to the alkaline adjustment unit 4; wherein, the carbon dioxide provided by the carbon dioxide generator 9 can enter the alkaline adjustment unit 4 through the carbon dioxide aeration disc 43, and dissolve in the water under the action of the alkaline mixing and propulsion device 42 to adjust the pH of the water.

[0030] Specifically, the bottom sidewall of the hard removal synchronous catalytic oxidation unit 2 is provided with a main water inlet 21 that is connected to the main water inlet pipe 1, the mixing flow booster 22 is located in the middle of the hard removal synchronous catalytic oxidation unit 2, the micro-nano bubble secondary cutter 23 is located at the bottom of the hard removal synchronous catalytic oxidation unit 2, and the water outlet overflow trough 25 is located on the upper sidewall of the hard removal synchronous catalytic oxidation unit 2.

[0031] Specifically, an ozone exhaust gas destroyer 24 is also provided on the top of the hardening synchronous catalytic oxidation unit 2.

[0032] Specifically, the induced crystallization filtration unit 3 includes a filter tank inlet pipe 31, a filter media support plate 32, and a sludge discharge valve 34. The filter tank inlet pipe 31 is connected to the outlet overflow trough 25. The filter media support plate 32 is disposed inside the induced crystallization filtration unit 3 and is used to support the induced crystallization filter media 33. The sludge discharge valve 34 is disposed at the bottom of the induced crystallization filtration unit 3, and the outlet 35 is disposed on the upper side wall of the induced crystallization filtration unit 3.

[0033] Specifically, the induced crystallization filter material 33 is a flaky calcite filter material with a size of 10 mm to 20 mm and a thickness of less than 10 mm.

[0034] Specifically, it also includes a dosing pump 6, a dosing pump inlet pipe 61, and a dosing pump outlet pipe 62. The calcium hydroxide storage tank 5 is connected to the dosing pump 6 through the dosing pump inlet pipe 61, and the water is introduced into the hardness removal synchronous catalytic oxidation unit 2 through the dosing pump outlet pipe 62.

[0035] Specifically, the alkaline adjustment unit 4 includes an alkali-adjusting inlet pipe 41 and an end outlet 44. The alkali-adjusting inlet pipe 41 is connected to the outlet 35 of the induced crystallization filter unit 3. The carbon dioxide aeration disc 43 is located at the bottom of the alkaline adjustment unit 4, and the end outlet 44 is located on the upper side wall of the alkaline adjustment unit 4.

[0036] Specifically, the gas-liquid synchronous pressurization pump 8 is connected to the ozone generator 7 through the mixing pump inlet pipe 81, connected to the main water inlet pipe 1 through the mixing pump water inlet pipe 82, and connected to the micro-nano bubble secondary cutter 23 through the dissolved gas water pipe 83, so that ozone and part of the raw water are pressurized and dissolved in the gas-liquid synchronous pressurization pump 8 to form dissolved gas water, and released at the micro-nano bubble secondary cutter 23 to form ozone micro-nano bubbles.

[0037] Specifically, the carbon dioxide generator 9 is connected to the carbon dioxide pressurization pump 10 through the carbon dioxide inlet pipe 101, and the carbon dioxide pressurization pump 10 is connected to the carbon dioxide aeration disc 43 through the carbon dioxide outlet pipe 102; the carbon dioxide generator 9 is an air compression and separation device, and the oxygen generated by the air compression and separation device is supplied to the ozone generator 7.

[0038] When the system is working, high-hardness, slightly polluted water enters the hardness removal synchronous catalytic oxidation unit 2 through the main water inlet pipe 1. Calcium hydroxide solution is added to the hardness removal synchronous catalytic oxidation unit 2 through the calcium hydroxide storage tank 5. Under the mixing action of the mixing and propulsion device 22, the high-hardness, slightly polluted water reacts with calcium hydroxide to generate calcium carbonate microcrystalline precipitate. The gas-liquid synchronous pressurization pump 8 draws part of the raw water from the main water inlet pipe 1, draws ozone gas from the ozone generation unit, and pressurizes and dissolves the ozone gas in the gas-liquid synchronous pressurization pump 8. The dissolved gas water is transported to the micro-nano bubble secondary cutter 23 for release to form ozone micro-nano bubbles. Under the action of the mixing and flow propulsion device 22, the ozone micro-bubbles come into contact with the calcium carbonate microcrystalline precipitate and are excited to generate hydroxyl radicals to oxidize and remove the recalcitrant trace organic pollutants in the water. A portion of the calcium carbonate crystals are discharged after settling at the bottom of the hardening synchronous catalytic oxidation unit 2. Another portion of the calcium carbonate microcrystals that are not easy to settle enter the induced crystallization filtration unit 3 from the overflow chute with the water flow. They are intercepted by the induced crystallization filter media 33 and continue to grow into secondary crystals on the surface of the flaky calcite filter media. They are then fixed in the bed of the induced crystallization filter media 33. The sediments that settle at the bottom of the induced crystallization filtration unit 3 due to gravity are discharged. After induced crystallization filtration, the water enters the alkaline recovery unit 4. To adjust the pH level, carbon dioxide supplied by carbon dioxide generator 9 enters the alkalinity adjustment unit 4 through carbon dioxide aeration disc 43 and dissolves in the water after induced crystallization filtration under the action of alkalinity adjusting mixing and propulsion device 42, so as to adjust the pH level of the water to a suitable range for drinking water.

[0039] Example 2 This embodiment provides a method for simultaneous purification of high-hardness, slightly polluted water, employing a high-hardness, slightly polluted water simultaneous purification system from Embodiment 1. The method includes the following steps: S1: Hardness Removal Synchronous Catalytic Oxidation. High-hardness, slightly polluted water supplied by the main inlet pipe 1 enters the bottom of the tank through the main inlet 21 of the hardness removal synchronous catalytic oxidation unit 2. Simultaneously, the dosing pump 6 draws calcium hydroxide solution from the calcium hydroxide storage tank 5 through the dosing pump inlet pipe 61 and pumps it into the middle of the hardness removal synchronous catalytic oxidation unit 2 through the dosing pump outlet pipe 62. Under the mixing action of the mixing and flow booster 22, calcium and magnesium ions in the high-hardness water react with calcium hydroxide to generate microcrystalline calcium carbonate precipitates. The microcrystalline calcium carbonate is uniformly dispersed in the water under the action of the mixing and flow booster 22. In this embodiment, the reaction pH is 10-11, and the generated microcrystalline calcium carbonate particle size is 0.05-100 μm.

[0040] At this time, the gas-liquid synchronous pressurization pump 8 draws part of the raw water from the main water inlet pipe 1 through the mixing pump inlet pipe 82, and draws ozone gas from the ozone generating unit through the mixing pump air inlet pipe 81. The ozone gas is then pressurized and dissolved in the gas-liquid synchronous pressurization pump 8. The dissolved gas water is transported through the dissolved gas water pipe 83 to the micro-nano bubble secondary cutter 23 at the bottom of the hardness removal synchronous catalytic oxidation unit 2 for release. The ozone gas is released and forms microbubbles. Under the action of the mixing flow promoter 22, the ozone microbubbles come into contact with the calcium carbonate microcrystals generated in the water from hardness removal, and are excited to generate hydroxyl radicals. In this embodiment, the pressure range of the gas-liquid synchronous pressurization dissolution process is 0.3-0.7 MPa, the ozone dosage is 1-5 times the TOC content in the water, and the generated micro-nano bubbles have a diameter of 1 nm-100 μm.

[0041] The addition of calcium hydroxide makes the water highly alkaline. In this alkaline atmosphere, the yield of hydroxyl radicals increases and their oxidizing power is enhanced. These highly reactive hydroxyl radicals can oxidize recalcitrant trace organic pollutants in the water, thus removing them from the slightly polluted water. Excess ozone gas is reduced to oxygen in the ozone tail gas destroyer 24 before being discharged, without causing any adverse environmental impact. In this embodiment, the hydraulic retention time of the simultaneous hardness removal and catalytic oxidation unit is 5-30 minutes. At this time, the step of simultaneous hardness removal and catalytic oxidation of slightly polluting organic matter is completed.

[0042] S2: Calcite-induced crystallization filtration. Large calcium carbonate crystals can settle at the bottom of the hardening synchronous catalytic oxidation unit 2 and be discharged through the slurry discharge valve 26. Small calcium carbonate microcrystals are not easily settled and enter the bottom of the induced crystallization filtration unit 3 through the filter tank inlet pipe 31 from the overflow chute. Water containing calcium carbonate microcrystals flows through the filter media support plate 32 into the bed of the induced crystallization filter media 33. The calcium carbonate microcrystals are trapped. Since the microcrystalline structure of calcium carbonate microcrystals is similar to that of the calcite filter media surface, the calcium carbonate crystals can continue to grow under the induction of calcite. Thus, the calcium carbonate microcrystals are fixed in the bed of the induced crystallization filter media 33 in the form of secondary growth crystals, and are efficiently and stably fixed in the filter media. The sediment at the bottom of the induced crystallization filtration unit 3 due to gravity settlement can be discharged through the sludge discharge valve 34. The clean water is discharged from the upper outlet 35. In this embodiment, the filter media bed thickness is 0.5-4m, and the filtration rate is 1-10 m / h. At this point, the induced crystallization filtration step is complete.

[0043] S3: Carbon Dioxide pH Adjustment. Due to the addition of calcium hydroxide in step S1, the water is alkaline, which removes hardness and provides an alkaline environment to promote the catalytic oxidation of organic pollutants. After induced crystallization filtration, the water is still alkaline, which is unsuitable for drinking water and has a poor taste. The pH needs to be adjusted to a suitable value. After induced crystallization filtration, the water enters the alkalinity adjustment unit 4 through the alkalinity adjustment inlet pipe 41. At this time, the carbon dioxide pressurization pump 10 draws in carbon dioxide supplied by the carbon dioxide generator 9 through the carbon dioxide inlet pipe 101 and delivers it to the carbon dioxide aeration disc 43 at the bottom of the alkalinity adjustment unit 4 through the carbon dioxide outlet pipe 102, releasing it into the water. Under the action of the reducing mixing and dissolving device 22, the pH value of the water can be reduced to 7.5-8.5. The treated, drinkable water is discharged from the end outlet 44. The pH adjustment step is now complete.

[0044] Example 3 In a case study of surface water in the Huai River basin used as a drinking water source, the total hardness of the water (calculated as calcium) was 297 mg / L, and the concentration of toluene, a characteristic micropollutant and difficult-to-degrade organic compound, was 0.88 ug / L. Although both the total hardness and the concentration of micropollutant organic compounds did not exceed the drinking water hygiene standards, the technical solution provided by this invention was used for treatment to improve the drinking water quality. The resulting effluent water showed a reduction in total hardness to 95 mg / L, no detectable toluene concentration, and a pH of 7.9. The high-hardness, slightly polluted water was effectively improved after treatment using the technical solution provided by this invention.

[0045] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A simultaneous purification system for high-hardness, slightly polluted water, characterized in that, include: The main inlet pipe (1) is used to supply high-hardness, slightly polluted water; The hardening synchronous catalytic oxidation unit (2) is connected to the main water inlet pipe (1). The hardening synchronous catalytic oxidation unit (2) is equipped with a main water inlet (21), a mixing flow generator (22), a micro-nano bubble secondary cutter (23), and an outlet overflow tank (25). The main water inlet pipe (1) is connected to the main water inlet (21). A calcium hydroxide storage tank (5) is used to supply calcium hydroxide solution to the hardening synchronous catalytic oxidation unit (2); A gas-liquid synchronous pressurizing pump (8) and an ozone generator (7) are connected. The ozone generator (7) is connected to the air inlet of the gas-liquid synchronous pressurizing pump (8). The water inlet of the gas-liquid synchronous pressurizing pump (8) is connected to the main water inlet pipe (1). The water outlet of the gas-liquid synchronous pressurizing pump (8) is connected to the micro-nano bubble secondary cutter (23). Ozone and some raw water can be pressurized and dissolved in the gas-liquid synchronous pressurizing pump (8) to form dissolved air water, and released at the micro-nano bubble secondary cutter (23) to form ozone micro-nano bubbles. The induced crystallization filtration unit (3) is provided with induced crystallization filter media (33), and the inlet of the induced crystallization filtration unit (3) is connected to the outlet overflow tank (25); The alkaline adjustment unit (4) is connected to the outlet (35) of the induced crystallization filtration unit (3). The alkaline adjustment unit (4) is equipped with an alkaline mixing and flow propeller (42) and a carbon dioxide aeration disc (43). A carbon dioxide generator (9) is connected to the alkaline adjustment unit (4); wherein, the carbon dioxide provided by the carbon dioxide generator (9) can enter the alkaline adjustment unit (4) through the carbon dioxide aeration disc (43) and dissolve in the water under the action of the alkaline mixing and propulsion device (42) to adjust the pH of the water.

2. The high-hardness, slightly polluted water simultaneous purification system according to claim 1, characterized in that, The bottom side wall of the hard removal synchronous catalytic oxidation unit (2) is provided with a main water inlet (21) that is connected to the main water inlet pipe (1). The mixing flow generator (22) is located in the middle of the hard removal synchronous catalytic oxidation unit (2). The micro-nano bubble secondary cutter (23) is located at the bottom of the hard removal synchronous catalytic oxidation unit (2). The water overflow tank (25) is located on the upper side wall of the hard removal synchronous catalytic oxidation unit (2).

3. The high-hardness, slightly polluted water simultaneous purification system according to claim 1, characterized in that, The top of the hardening synchronous catalytic oxidation unit (2) is also provided with an ozone exhaust gas destroyer (24).

4. The high-hardness, slightly polluted water simultaneous purification system according to claim 1, characterized in that, The induced crystallization filtration unit (3) includes a filter tank inlet pipe (31), a filter media support plate (32), and a sludge discharge valve (34). The filter tank inlet pipe (31) is connected to the outlet overflow trough (25). The filter media support plate (32) is set inside the induced crystallization filtration unit (3) and is used to support the induced crystallization filter media (33). The sludge discharge valve (34) is set at the bottom of the induced crystallization filtration unit (3), and the outlet (35) is set on the upper side wall of the induced crystallization filtration unit (3).

5. The high-hardness, slightly polluted water simultaneous purification system according to claim 4, characterized in that, The induced crystallization filter material (33) is a flaky calcite filter material with a size of 10 mm to 20 mm and a thickness of less than 10 mm.

6. The high-hardness, slightly polluted water simultaneous purification system according to claim 1, characterized in that, It also includes a dosing pump (6), a dosing pump inlet pipe (61) and a dosing pump outlet pipe (62). The calcium hydroxide storage tank (5) is connected to the dosing pump (6) through the dosing pump inlet pipe (61) and is fed into the hardness removal synchronous catalytic oxidation unit (2) through the dosing pump outlet pipe (62).

7. The high-hardness, slightly polluted water simultaneous purification system according to claim 1, characterized in that, The alkaline adjustment unit (4) includes an alkali-adjusting inlet pipe (41) and an end outlet (44). The alkali-adjusting inlet pipe (41) is connected to the outlet (35) of the induced crystallization filter unit (3). The carbon dioxide aeration disc (43) is located at the bottom of the alkaline adjustment unit (4), and the end outlet (44) is located on the upper side wall of the alkaline adjustment unit (4).

8. The high-hardness, slightly polluted water simultaneous purification system according to claim 1, characterized in that, The gas-liquid synchronous pressurization pump (8) is connected to the ozone generator (7) through the mixing pump inlet pipe (81), connected to the main water inlet pipe (1) through the mixing pump water inlet pipe (82), and connected to the micro-nano bubble secondary cutter (23) through the dissolved gas water pipe (83), so that ozone and part of the raw water are pressurized and dissolved in the gas-liquid synchronous pressurization pump (8) to form dissolved gas water, and released at the micro-nano bubble secondary cutter (23) to form ozone micro-nano bubbles.

9. A simultaneous purification system for high-hardness, slightly polluted water according to claim 1, characterized in that, It also includes a carbon dioxide pressurizing pump (10), the carbon dioxide generator (9) is connected to the carbon dioxide pressurizing pump (10) through a carbon dioxide inlet pipe (101), and the carbon dioxide pressurizing pump (10) is connected to the carbon dioxide aeration disc (43) through a carbon dioxide outlet pipe (102); the carbon dioxide generator (9) is an air compression separation device, and the oxygen generated by the air compression separation device is supplied to the ozone generator (7).

10. A method for simultaneous purification of high-hardness, slightly polluted water, characterized in that, The high-hardness, slightly polluted water simultaneous purification system according to any one of claims 1-9 includes the following steps: High-hardness, slightly polluted water is introduced into the hardness removal synchronous catalytic oxidation unit (2) through the main inlet pipe (1). Calcium hydroxide solution is added into the hardness removal synchronous catalytic oxidation unit (2) through the calcium hydroxide storage tank (5). Under the mixing action of the mixing pump (22), the high-hardness, slightly polluted water reacts with calcium hydroxide to generate calcium carbonate microcrystalline precipitate. The gas-liquid synchronous pressurizing pump (8) draws part of the raw water from the main water inlet pipe (1), draws ozone gas from the ozone generating unit, and pressurizes and dissolves the ozone gas in the gas-liquid synchronous pressurizing pump (8). The dissolved gas water is transported to the micro-nano bubble secondary cutter (23) for release to form ozone micro-nano bubbles. Under the action of the mixing and flow propulsion device (22), the ozone micro-bubbles come into contact with the calcium carbonate microcrystalline precipitate and generate hydroxyl radicals to oxidize and remove the difficult-to-degrade trace organic pollutants in the water. Some calcium carbonate crystals are discharged after settling at the bottom of the hardening synchronous catalytic oxidation unit (2). Other calcium carbonate microcrystals that are not easy to settle enter the induced crystallization filtration unit (3) from the overflow chute with the water flow. They are intercepted by the induced crystallization filter media (33) and continue to grow into secondary crystals on the surface of the flaky calcite filter media. They are then fixed in the bed of the induced crystallization filter media (33). The sediments that settle at the bottom of the induced crystallization filtration unit (3) due to gravity are discharged. After induced crystallization filtration, the water enters the alkaline recovery unit (4). To adjust the pH level, the carbon dioxide supplied by the carbon dioxide generator (9) enters the alkalinity adjustment unit (4) through the carbon dioxide aeration disc (43) and dissolves in the water after induced crystallization filtration under the action of the alkalinity adjustment mixing and propulsion device (42) so as to adjust the pH level of the water to a suitable range for drinking water.

Images