A high-efficiency treatment system for high-concentration wastewater

Abstract

The utility model provides a kind of high concentration wastewater treatment system of efficient treatment, including regulating pool, wet oxidation pretreatment unit, fenton pretreatment pool, primary coagulation sedimentation tank, anaerobic treatment tank, two-stage anoxic-aerobic (AO) treatment tank, secondary coagulation sedimentation tank and disinfection tank.The utility model provides a kind of high concentration wastewater treatment system of efficient treatment, including the pretreatment pool of wet oxidation+Fenton oxidation combination, the biochemical degradation tank of anaerobic+two-stage anoxic-aerobic (AO) treatment tank combination, can realize the efficient treatment of high concentration, refractory wastewater, maximum limit wastewater in pollutant digestion or degradation, finally effluent reaches the goal of qualified discharge;Treatment effect is good, and operating cost is low, can be widely applied in chemical industry, dye, pharmaceutical, tanning and other various refractory wastewater treatment, reduce the pollution of wastewater to environment.

Description

Technical Field

[0001] This utility model belongs to the field of environmental engineering technology, and in particular relates to a high-efficiency wastewater treatment system. Background Technology

[0002] Currently, the chemical, dye, pharmaceutical, and leather industries generate large amounts of high-concentration, recalcitrant wastewater with COD values ​​ranging from 50,000 to 200,000 mg / L. This high-concentration, recalcitrant wastewater is typically treated as hazardous waste, including physical, chemical, biological, thermal, and landfill treatments. Furthermore, it requires adherence to strict environmental impact assessments and transfer manifest management procedures. Not only are the treatment costs high (hazardous waste treatment costs 3,000 yuan / ton), but these traditional treatment processes also suffer from low efficiency and a high risk of secondary pollution.

[0003] Therefore, there is an urgent need for a new and efficient method and system for treating high-concentration wastewater. Utility Model Content

[0004] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide a high-efficiency wastewater treatment system.

[0005] To achieve the above objectives, the solution adopted by this utility model is as follows:

[0006] This utility model provides a high-efficiency wastewater treatment system, including an equalization tank, a wet oxidation pretreatment unit, a Fenton pretreatment tank, a primary coagulation sedimentation tank, an anaerobic treatment tank, a two-stage anoxic-aerobic (AO) treatment tank, a secondary coagulation sedimentation tank, and a disinfection tank; wherein, the equalization tank and the wet oxidation pretreatment unit are connected in sequence by pipelines, and the Fenton pretreatment tank, the primary coagulation sedimentation tank, the anaerobic treatment tank, the two-stage anoxic-aerobic (AO) treatment tank, the secondary coagulation sedimentation tank, and the disinfection tank are separated in sequence by baffles and connected by flow dividers.

[0007] Preferably, the regulating tank is provided with a first inlet pipe and a first outlet pipe, and a bar screen is provided on the first inlet pipe to intercept large suspended solids and large sand particles in the initial wastewater.

[0008] Preferably, the wet oxidation pretreatment unit includes at least one high-temperature and high-pressure oxidation reactor. Each high-temperature and high-pressure oxidation reactor is provided with a first air inlet pipe, a second air inlet pipe, a second water inlet pipe, a second water outlet pipe, and a first air outlet pipe. A gas storage tank for introducing inert gas is provided on the first air inlet pipe, a gas compression device for introducing air or pure oxygen is provided on the second air inlet pipe, and a condensation device for cooling the water outlet is provided on the second water outlet pipe. The first air outlet pipe is connected to the equalization tank.

[0009] Preferably, the Fenton pretreatment tank is provided with a first reagent pipeline and a second reagent pipeline. The first reagent pipeline is connected to a ferrous sulfate storage tank for adding a ferrous sulfate solution that undergoes Fenton oxidation, and the second reagent pipeline is connected to a hydrogen peroxide storage tank for adding a hydrogen peroxide solution that undergoes Fenton oxidation.

[0010] Preferably, the two-stage anoxic-aerobic (AO) treatment tanks each include an anoxic tank and an aerobic tank. Biological contact oxidation packing is provided in both aerobic tanks. Aeration heads are provided at the bottom of the anoxic-aerobic tank section of the two-stage anoxic-aerobic (AO) treatment tanks. A first sludge return pipe is provided at the bottom of the aerobic tank in the first-stage anoxic-aerobic tank section, and the first sludge return pipe flows from the bottom into the anoxic tank of the first-stage anoxic-aerobic tank section and the anaerobic treatment tank. A second sludge return pipe is provided at the bottom of the aerobic tank in the second-stage anoxic-aerobic tank section, and the second sludge return pipe flows from the bottom into the anoxic tank of the second-stage anoxic-aerobic tank section.

[0011] Preferably, the primary coagulation sedimentation tank and the secondary coagulation sedimentation tank each include a coagulation tank, a flocculation tank, and an inclined tube sedimentation tank, which are sequentially separated by baffles and connected by a flow divider. A third agent pipeline is provided on the coagulation tank, and a fourth agent pipeline is provided on the flocculation tank. The third agent pipeline is connected to a coagulant storage tank for adding coagulant solution, and the fourth agent pipeline is connected to a flocculant storage tank for adding flocculant solution. Hexagonal honeycomb inclined tube packing is provided in the inclined tube sedimentation tank. A third sludge return pipeline is provided at the bottom of the inclined tube sedimentation tank of the secondary coagulation sedimentation tank, and the third sludge return pipeline flows from the bottom into the anoxic-aerobic tank of the two-stage anoxic-aerobic (AO) treatment tank.

[0012] Preferably, a primary pH adjustment tank is provided between the wet oxidation pretreatment unit and the Fenton pretreatment tank, and a secondary pH adjustment tank is provided between the Fenton pretreatment tank and the primary coagulation sedimentation tank. A fifth and a sixth reagent pipeline are provided in the primary pH adjustment tank, and a seventh and an eighth reagent pipeline are provided in the secondary pH adjustment tank. The fifth and seventh reagent pipelines are connected to an alkali storage tank for adding alkali, and the sixth and eighth reagent pipelines are connected to an acid storage tank for adding acid.

[0013] Preferably, the equalization tank, the high-temperature and high-pressure oxidation reactor of the wet oxidation pretreatment unit, the primary pH equalization tank, the Fenton pretreatment tank, and the secondary pH equalization tank are all equipped with stirring devices. Each of the two aerobic tanks in the primary pH equalization tank, the Fenton pretreatment tank, the secondary pH equalization tank, the two-stage coagulation sedimentation tank, and the two-stage anoxic-aerobic (AO) treatment tank is equipped with a sludge discharge pipeline at the bottom of each tank. Each sludge discharge pipeline is connected to a sludge tank. Each sludge discharge pipeline is equipped with a sludge discharge pipeline valve and a sludge discharge pump. Each chemical agent pipeline is equipped with a chemical agent pipeline valve and a chemical agent pump.

[0014] Preferably, it also includes a microcomputer control system, which is electrically connected to the power supply device and to each stirring device, each sludge discharge pipeline valve, each sludge discharge pump, each chemical pipeline valve and each chemical pump, and controls their opening and closing.

[0015] Beneficial effects

[0016] This utility model provides a high-efficiency wastewater treatment system for high-concentration wastewater, including a pretreatment tank combining wet oxidation and Fenton oxidation, and a biochemical degradation tank combining anaerobic and two-stage anoxic-aerobic (AO) treatment tanks. It can efficiently treat high-concentration, recalcitrant wastewater, maximizing the dissolution or degradation of pollutants in the wastewater, and ultimately achieving the goal of qualified discharge of the effluent. It has good treatment effect and low operating cost, and can be widely used in the treatment of various recalcitrant wastewaters from chemical, dye, pharmaceutical, and leather industries, reducing wastewater pollution to the environment. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the high-efficiency wastewater treatment system involved in this utility model.

[0018] Figure 2 This is a schematic diagram of the structure of the wet oxidation pretreatment unit of the high-efficiency high-concentration wastewater treatment system involved in this utility model. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0021] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0022] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0023] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0024] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0025] Therefore, the following solutions are proposed:

[0026] See Figure 1This utility model provides a high-efficiency wastewater treatment system, including an equalization tank 1, a wet oxidation pretreatment unit 2, a Fenton pretreatment tank 3, a primary coagulation sedimentation tank 4, an anaerobic treatment tank 5, a two-stage anoxic-aerobic (AO) treatment tank 6, a secondary coagulation sedimentation tank 7, and a disinfection tank 8; wherein, the equalization tank 1 and the wet oxidation pretreatment unit 2 are connected in sequence by pipelines, and the Fenton pretreatment tank 3, the primary coagulation sedimentation tank 4, the anaerobic treatment tank 5, the two-stage anoxic-aerobic (AO) treatment tank 6, the secondary coagulation sedimentation tank 7, and the disinfection tank 8 are separated by partitions and connected by baffles.

[0027] According to the present invention, a first inlet pipe 11 and a first outlet pipe 12 are provided on the equalization tank 1. A bar screen 9 is provided on the first inlet pipe 11. The initial wastewater sent into the equalization tank 1 can be intercepted and removed by the bar screen 9, such as large suspended solids and large sand particles.

[0028] The equalization tank 1 of this utility model has the known function of equalizing and regulating the quality and quantity of wastewater, so as to avoid the problem of abnormal wastewater treatment process caused by large changes in water quality and quantity during the discharge process, and improve the wastewater treatment effect.

[0029] According to the present invention, a stirring device 13 is also provided in the equalization tank 1 to stir the wastewater in the equalization tank 1 to prevent suspended particulate impurities from settling.

[0030] According to the present invention, the wastewater treated by the equalization tank 1 enters the wet oxidation pretreatment unit 2 through the first effluent pipe 12.

[0031] According to the present invention, the wet oxidation pretreatment unit 2 is used to oxidize wastewater under high temperature and high pressure using air containing oxygen or pure oxygen as an oxidant to form dissolved or suspended organic matter or reduced inorganic matter, generating inorganic matter and small molecule organic matter including carbon dioxide, nitrogen and water.

[0032] According to the solution of this utility model, combined with Figure 2 As shown, the wet oxidation pretreatment unit 2 includes at least one high-temperature and high-pressure oxidation reactor 21, and each high-temperature and high-pressure oxidation reactor 21 is provided with a first air inlet pipe 211, a second air inlet pipe 212, a second water inlet pipe 213, a second water outlet pipe 214 and a first air outlet pipe 215.

[0033] According to the present invention, a gas storage tank 22 for introducing inert gas is provided on the first air inlet pipe 211. The pressure inside the high temperature and high pressure oxidation reactor 21 is 1.5-2.5 MPa by introducing inert gas through the gas storage tank 22.

[0034] According to the present invention, a gas compression device 23 for introducing air or pure oxygen as an oxidant is provided on the second air inlet pipe 212. The gas compression device 23 introduces oxygen-containing air or pure oxygen for oxidizing the wastewater in the high-temperature and high-pressure oxidation reactor 21.

[0035] According to the present invention, each high-temperature and high-pressure oxidation reactor 21 is provided with a heating device 24 for heating the wastewater inside. The heating device 24 can adopt a heat transfer oil heating method, for example, including a jacket 241 that surrounds the high-temperature and high-pressure oxidation reactor 21, an oil inlet pipe 242 and an oil outlet pipe 243 connected to the jacket 241 for introducing and discharging heat transfer oil, and a heat transfer oil storage tank 244 and a heat transfer oil furnace 245 installed between the oil inlet pipe 242 and the oil outlet pipe 243. Heat transfer oil is injected into the heat transfer oil storage tank 244 at regular intervals and in a quantitative manner. After being heated by the heat transfer oil furnace 245, the heat transfer oil is introduced into the jacket 241 surrounding the high-temperature and high-pressure oxidation reactor 21 through the oil inlet pipe 242, so that the wastewater inside the high-temperature and high-pressure oxidation reactor 21 is heated to a temperature of 150-250°C. The heat transfer oil is then discharged to the heat transfer oil storage tank 244 through the oil outlet pipe 243 for recycling. The heating device 24 can also be a thermoelectric furnace or other known heating methods.

[0036] According to the present invention, in the high-temperature and high-pressure oxidation reactor 21, wastewater treated in the equalization tank 1 is introduced into the reactor 21 through the second inlet pipe 213. The pressure inside the reactor 21 is maintained at 1.5-2.5 MPa by introducing inert gas. The wastewater inside the reactor 21 is heated to 150-250°C by the heating device 24. Oxygen-containing air or pure oxygen is introduced through the gas compression device 23 as an oxidant to oxidize the wastewater inside the reactor 21. In some cases, a suitable catalyst can also be added to further oxidize the reactor. In some embodiments, the oxidation reaction time is 30-60 minutes, and the wastewater after wet oxidation forms dissolved or suspended organic matter or reduced inorganic matter, generating inorganic matter and small molecule organic matter including carbon dioxide, nitrogen and water. A condenser 25 for cooling the effluent is provided on the second effluent pipe 214. The wastewater after being treated by the high temperature and high pressure oxidation reactor 21 is discharged through the second effluent pipe 214. The liquid wastewater cooled by the condenser 25 enters the Fenton pretreatment tank 3. At the same time, the gas phase steam discharged through the first gas outlet pipe 215 is fed into the equalization tank 1 for further treatment and recycling.

[0037] According to the present invention, an acid-adjusting reaction tank (not shown in the figure) can also be provided between the equalization tank 1 and the wet oxidation pretreatment tank 2. This tank is used to react the wastewater from the equalization tank 1 with the added dilute sulfuric acid to adjust the pH value of the wastewater to 3.5-6.5. The slightly acidic wastewater with a pH value of 3.5-6.5 is then introduced into the wet oxidation pretreatment tank 2. Furthermore, the pH value of the wastewater in the wet oxidation pretreatment tank 2 is adjusted to 7.0-9.0 for the oxidation reaction to occur. The slightly alkaline wastewater is more conducive to the oxidation reaction in the wet oxidation pretreatment tank 2.

[0038] According to the present invention, the Fenton pretreatment tank 3 is used to carry out Fenton oxidation reaction with wastewater and a Fenton oxidation system composed of ferrous electrolytic salt and hydrogen peroxide, further removing CODcr and color from the wastewater, breaking the chain of heterocyclic substances, and oxidizing organic matter in the wastewater, including phenols, benzene ring aromatic compounds and alkyl aromatic hydrocarbons, into inorganic matter and small molecule organic matter including nitrogen dioxide, carbon dioxide, water, nitrogen and sulfate ions. The treated wastewater enters the primary coagulation sedimentation tank 4.

[0039] According to the present invention, a first reagent pipeline 31 and a second reagent pipeline 32 are provided on the Fenton pretreatment tank 3. The first reagent pipeline 31 is connected to a ferrous sulfate storage tank 33 for adding a ferrous sulfate solution that undergoes Fenton oxidation. The second reagent pipeline 32 is connected to a hydrogen peroxide storage tank 34 for adding a hydrogen peroxide solution that undergoes Fenton oxidation. In some embodiments, the ferrous sulfate storage tank 33 is also connected to a ferrous sulfate preparation tank 35. The ferrous sulfate solution is prepared in the ferrous sulfate preparation tank 35, and the prepared ferrous sulfate solution is then passed into the ferrous sulfate storage tank 33 for storage.

[0040] According to the present invention, ferrous sulfate solution is added to Fenton pretreatment tank 3 from ferrous sulfate storage tank 33 via first reagent pipeline 31, and hydrogen peroxide solution is added to Fenton pretreatment tank 3 from hydrogen peroxide storage tank 34 via second reagent pipeline 32. Ferrous sulfate solution and hydrogen peroxide solution are mixed in Fenton pretreatment tank 3 to form Fenton oxidizing reagent. The two can react to generate hydroxyl radicals with strong oxidizing power. In some embodiments, catalyst packing can also be provided in Fenton pretreatment tank 3. The ferrous sulfate and hydrogen peroxide mixed solution in Fenton pretreatment tank 3 reacts with catalyst packing to further catalyze the generation of hydroxyl radicals with strong oxidizing power. The generated hydroxyl radicals react with recalcitrant organic matter in wastewater (e.g., heterocyclic organic matter including phenols, benzene ring aromatic compounds and alkyl aromatic hydrocarbons) to generate organic free radicals, causing them to open rings and break chains, and finally oxidize and decompose into inorganic matter and small molecule organic matter including nitrogen dioxide, carbon dioxide, water, nitrogen gas and sulfate ions.

[0041] According to the present invention, in the Fenton pretreatment tank 3, the catalyst packing can be a fixed bed or a fluidized bed, preferably a fluidized bed. The fluidized bed setting is more conducive to the crystallization or precipitation of iron compounds generated by the Fenton oxidation reaction on the surface of the packing carrier through the fluidized bed, which not only reduces the generated iron sludge, but also forms catalytic iron oxide on the surface of the packing carrier, further improving the mass transfer efficiency and further improving the COD removal efficiency of the wastewater.

[0042] According to the present invention, a primary pH adjustment tank 9a and a secondary pH adjustment tank 9b can be respectively set in the front and rear sections of the Fenton pretreatment tank 3. The primary pH adjustment tank 9a is equipped with a fifth reagent pipe 91 and a sixth reagent pipe 92, and the secondary pH adjustment tank 9b is equipped with a seventh reagent pipe 93 and an eighth reagent pipe 94. The fifth reagent pipe 91 and the seventh reagent pipe 93 are connected to an alkali storage tank 95 for adding alkali solution, and the sixth reagent pipe 92 and the eighth reagent pipe 94 are connected to an acid storage tank 96 for adding acid solution. In some embodiments, the alkali storage tank 95 is also connected to an alkali preparation tank 97, for example, sodium hydroxide alkali solution is prepared in the alkali preparation tank 97, and the prepared alkali solution is then passed into the alkali storage tank 95 for storage. The acid storage tank 96 is also connected to an acid preparation tank 98, for example, hydrochloric acid solution is prepared in the acid preparation tank 98, and the prepared acid solution is then passed into the acid storage tank 96 for storage.

[0043] According to the present invention, the primary coagulation sedimentation tank 4 is used to react the wastewater treated by the Fenton pretreatment tank 3 with the added flocculant to generate a large amount of flocculent precipitate, and remove the flocculent precipitate by inclined tube sedimentation. The supernatant enters the anaerobic treatment tank 5.

[0044] According to the present invention, the primary coagulation sedimentation tank 4 includes a coagulation tank 41, a flocculation tank 42, and an inclined tube sedimentation tank 43, which are separated by baffles and connected by a flow divider. In some embodiments, a third agent pipeline 44 is provided on the coagulation tank 41, and a fourth agent pipeline 45 is provided on the flocculation tank 42. The third agent pipeline 44 is connected to a coagulant storage tank 46 and is used to add coagulant solutions such as ferric chloride (FC), polyaluminum chloride (PAC), and polyferric sulfate (PFS). The fourth agent pipeline 45 is connected to a flocculant storage tank 47 and is used to add flocculant solutions such as polyacrylamide (PAM). In some embodiments, the coagulant storage tank 46 is also connected to the coagulant preparation tank 48, where the coagulant solution is prepared and then the prepared coagulant solution is passed into the coagulant storage tank 46 for storage; the flocculant storage tank 47 is also connected to the flocculant preparation tank 49, where the flocculant solution is prepared and then the prepared flocculant solution is passed into the flocculant storage tank 49 for storage.

[0045] According to the present invention, the coagulant solution is introduced into the coagulation tank 41 through the third reagent pipe 44. In the coagulation tank 41, the coagulant reacts with the wastewater to form fine suspended solids. The flocculant solution is introduced into the flocculation tank 42 through the fourth reagent pipe 45. In the flocculation tank 42, the flocculant reacts with the wastewater to generate flocculent suspended solids and precipitates with larger particle sizes. The effluent from the coagulation tank 41 and the flocculation tank 42 is sent into the inclined tube sedimentation tank 43. The inclined tube sedimentation tank 43 is equipped with hexagonal honeycomb inclined tube packing 431. Solid-liquid separation is carried out by the inclined tube sedimentation method to remove the flocculent precipitates. The supernatant enters the anaerobic treatment tank 5.

[0046] According to the present invention, the anaerobic treatment tank 5 is used to hydrolyze and acidify wastewater. Nutrients such as glucose, ammonium carbonate, and potassium dihydrogen phosphate can be added. Generally, aeration is not required. Setting up an anaerobic treatment tank at the front end of the AO biological treatment tank can improve the biodegradability of the wastewater and provide better conditions for the microbial degradation in the subsequent aerobic biological contact oxidation tank.

[0047] According to the present invention, the two-stage anoxic-aerobic (AO) treatment tank 6 is used to oxidize wastewater with packing material to decompose organic matter, nitrates, nitrites and ammonia nitrogen in the wastewater, and the resulting wastewater enters the secondary coagulation sedimentation tank 7.

[0048] According to the present invention, the two-stage anoxic-aerobic (AO) treatment tank 6 includes an anoxic tank 61 and an aerobic tank 62. Biological contact oxidation packing material 63 is provided in both aerobic tanks 62. Aeration heads 64 are provided at the bottom of the anoxic and aerobic tanks of the two-stage anoxic-aerobic (AO) treatment tank 6. The wastewater in the anoxic and aerobic tanks of the two-stage anoxic-aerobic (AO) treatment tank 6 is aerated by setting the aeration heads 64, and the DO content in the wastewater is adjusted by controlling the aeration rate. The DO content in the aerobic tank is controlled at 3~4 mg / L (air-to-water ratio controlled at (15~20):1), and the DO content in the anoxic tank is controlled at about 0.5 mg / L.

[0049] According to the present invention, a first sludge return pipe 65 is provided at the bottom of the aerobic tank 62 of the first-stage anoxic tank-aerobic tank 6. The first sludge return pipe 65 is connected from the bottom to the anoxic tank 61 and the anaerobic treatment tank 5 of the first-stage anoxic tank-aerobic tank 6. A second sludge return pipe 66 is provided at the bottom of the aerobic tank 62 of the second-stage anoxic tank-aerobic tank 6. The second sludge return pipe 66 is connected from the bottom to the anoxic tank 61 of the second-stage anoxic tank-aerobic tank 6.

[0050] According to the present invention, in the two-stage anoxic-aerobic (AO) treatment tank 6, a biological contact oxidation packing material 63 is used. Microorganisms are attached to the packing material in the form of a biofilm, and some exist in the wastewater in the form of bioflocs. The main purpose is to utilize the biofilm on the packing material to degrade pollutants such as organic matter and ammonia nitrogen. The quality of the packing material determines whether microorganisms can be adsorbed and whether they can grow and reproduce well. It has a great impact on the removal rate of CODcr, BOD5, and NH3-N in wastewater. High-density ecological packing material is usually used. For example, at a water depth of 2.0m, the packing layer height is set at 1.6m. This packing material has a long service life, a large specific surface area, a certain degree of flexibility and rigidity, good resilience, and the material used is lighter than water. It can spread evenly in water and cut bubbles in a dense and multi-layered manner, which greatly improves the dissolved oxygen transfer coefficient, reduces air volume, and saves energy.

[0051] According to the present invention, the secondary coagulation sedimentation tank 7 is used to react wastewater with the added flocculant again to generate a large amount of flocculent precipitate, and remove the flocculent precipitate by inclined tube sedimentation. The supernatant enters the disinfection tank 8.

[0052] According to the present invention, the secondary coagulation sedimentation tank 7 of the present invention can adopt the same structure as the primary coagulation sedimentation tank 4, including a coagulation tank 71, a flocculation tank 72 and an inclined tube sedimentation tank 73 that are separated by baffles and connected by flow deflection. In some embodiments, a ninth reagent pipe 74 is provided on the coagulation tank 71 and a tenth reagent pipe 75 is provided on the flocculation tank 72. The ninth reagent pipe 74 is connected to the coagulant storage tank 46 and is used to add coagulant solutions such as ferric chloride (FC), polyaluminum chloride (PAC), and polyferric sulfate (PFS). The tenth reagent pipe 75 is connected to the flocculant storage tank 47 and is used to add flocculant solutions such as polyacrylamide (PAM).

[0053] According to the present invention, the coagulant solution is introduced into the coagulation tank 71 through the ninth reagent pipe 74. In the coagulation tank 71, the coagulant reacts with the wastewater to form fine suspended solids. The coagulant solution is introduced into the flocculation tank 72 through the tenth reagent pipe 75. In the flocculation tank 72, the coagulant reacts with the wastewater to generate flocculent suspended solids and precipitates with larger particle sizes. The effluent from the coagulation tank 71 and the flocculation tank 72 is sent into the inclined tube sedimentation tank 73. The inclined tube sedimentation tank 73 is equipped with hexagonal honeycomb inclined tube packing. Solid-liquid separation is carried out by the inclined tube sedimentation method to remove the flocculent precipitates. The supernatant enters the disinfection tank 8.

[0054] According to the present invention, a third sludge return pipeline 76 is provided at the bottom of the inclined tube sedimentation tank 73 of the secondary coagulation sedimentation tank 7. The third sludge return pipeline 76 is connected from the bottom to the anoxic tank 61-aerobic tank 62 of the two-stage anoxic-aerobic (AO) treatment tank 6.

[0055] According to the present invention, the disinfection tank 8 is used to disinfect wastewater by contacting it with added chlorine tablets or chlorine dioxide or ozone, thereby decomposing and removing bacteria or viruses in the wastewater, and discharging the wastewater after it meets the standards.

[0056] According to the present invention, the high-efficiency high-concentration wastewater treatment system of the present invention is equipped with stirring devices in the equalization tank 1, the high-temperature and high-pressure oxidation reactor 21 of the wet oxidation pretreatment unit 2, the primary pH equalization tank 9a, the Fenton pretreatment tank 3 and the secondary pH equalization tank 9b. Each tank bottom of the primary pH equalization tank 9a, the Fenton pretreatment tank 3, the secondary pH equalization tank 9b, the primary coagulation sedimentation tank 4, the two aerobic tanks 62 of the two-stage anoxic-aerobic (AO) treatment tank 6 and the secondary coagulation sedimentation tank 7 is equipped with a sludge discharge pipeline 101. Each sludge discharge pipeline 101 is connected to the sludge tank 10. Each sludge discharge pipeline 101 is equipped with a sludge discharge pipeline valve 101a and a sludge discharge pump 101b. Each chemical agent pipeline is equipped with a chemical agent pipeline valve 111a and a chemical agent pump 111b.

[0057] According to the present invention, the high-efficiency wastewater treatment system for high-concentration wastewater further includes a microcomputer control system (not shown in the figure). The microcomputer control system is electrically connected to a power supply device and to each stirring device, each sludge discharge pipeline valve, each sludge discharge pump, each chemical agent pipeline valve, and each chemical agent pump, controlling their opening and closing. In some embodiments, each tank may also be equipped with a level gauge and a flow controller (not shown in the figure), each level gauge and each flow controller being electrically connected to the microcomputer control system.

[0058] Taking the wastewater discharged from the CDMO production workshop of a pharmaceutical factory as an example, after long-term monitoring, the initial COD of the wastewater to be treated is about 130,000 mg / L. The removal efficiency and treatment cost of each treatment unit of the high-efficiency wastewater treatment system of this utility model are listed in Table 1.

[0059] Table 1

[0060] wet oxidation pretreatment tank 130000 52000 60% 105 Fenton pretreatment tank 52000 36400 30% 55 Coagulation sedimentation tank 36400 34580 5% 1.5 anaerobic pond 34580 6916 80% 0.5 Level 1 AO pool 6916 2766.4 40% 1.2 Level 2 AO pool 2766.4 414.96 85% 1.2 Secondary coagulation sedimentation tank 414.96 414.96 - 0.3 Disinfection pool 414.96 394 5% 0.2

[0061] As shown in Table 1, the high-efficiency wastewater treatment system of this invention is used to treat high-concentration wastewater (initial COD in the range of 100,000-150,000 mg / L). First, the wastewater passes through a pretreatment tank combining wet oxidation and Fenton oxidation, which oxidizes and decomposes the high-concentration, recalcitrant organic matter in the wastewater into inorganic and small-molecule organic matter such as nitrogen dioxide, carbon dioxide, water, nitrogen gas, and sulfate ions, rapidly controlling the effluent COD below 35,000 mg / L. Then, the wastewater passes through a biochemical degradation tank combining anaerobic and two-stage AO biochemical processes, where the organic matter in the wastewater is decomposed by microbial packing. Since the COD of the wastewater is already low at this point, the biochemical degradation tank combining anaerobic and two-stage AO biochemical processes can achieve rapid treatment while ensuring treatment efficiency, and also greatly reduces treatment costs. The final total treatment cost is 164.9 yuan / ton of water, which is significantly lower than the cost of treating this high-concentration wastewater as hazardous waste (3,000 yuan / ton).

[0062] This utility model discloses a high-efficiency wastewater treatment system, which includes a pretreatment tank combining wet oxidation and Fenton oxidation, and a biochemical degradation tank combining anaerobic and two-stage AO biochemical processes. It can efficiently treat high-concentration and difficult-to-degrade wastewater, maximize the elimination or degradation of pollutants in the wastewater, and ultimately achieve the goal of qualified discharge of the effluent.

[0063] Moreover, this utility model's high-efficiency wastewater treatment system has good treatment effect and low operating cost, and can be widely used in the treatment of various difficult-to-treat wastewaters such as chemical, dye, pharmaceutical, and leather industries, reducing wastewater pollution to the environment.

[0064] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A high-efficiency wastewater treatment system, characterized in that, It includes an equalization tank, a wet oxidation pretreatment unit, a Fenton pretreatment tank, a primary coagulation sedimentation tank, an anaerobic treatment tank, a two-stage anoxic-aerobic (AO) treatment tank, a secondary coagulation sedimentation tank, and a disinfection tank. The equalization tank and the wet oxidation pretreatment unit are connected in sequence by pipelines. The Fenton pretreatment tank, the primary coagulation sedimentation tank, the anaerobic treatment tank, the two-stage anoxic-aerobic (AO) treatment tank, the secondary coagulation sedimentation tank, and the disinfection tank are separated by baffles and connected by flow dividers.

2. The high-efficiency wastewater treatment system according to claim 1, characterized in that, The regulating tank is equipped with a first inlet pipe and a first outlet pipe. A bar screen is installed on the first inlet pipe to intercept large suspended solids and large sand particles in the initial wastewater.

3. The high-efficiency wastewater treatment system according to claim 1, characterized in that, The wet oxidation pretreatment unit includes at least one high-temperature and high-pressure oxidation reactor. Each high-temperature and high-pressure oxidation reactor is provided with a first air inlet pipe, a second air inlet pipe, a second water inlet pipe, a second water outlet pipe, and a first air outlet pipe. A gas storage tank for introducing inert gas is provided on the first air inlet pipe, a gas compression device for introducing air or pure oxygen is provided on the second air inlet pipe, and a condensation device for cooling the water outlet is provided on the second water outlet pipe. The first air outlet pipe is connected to the equalization tank.

4. The high-efficiency wastewater treatment system according to claim 1, characterized in that, The Fenton pretreatment tank is equipped with a first reagent pipeline and a second reagent pipeline. The first reagent pipeline is connected to a ferrous sulfate storage tank for adding a ferrous sulfate solution that undergoes Fenton oxidation. The second reagent pipeline is connected to a hydrogen peroxide storage tank for adding a hydrogen peroxide solution that undergoes Fenton oxidation.

5. The high-efficiency wastewater treatment system according to claim 1, characterized in that, The two-stage anoxic-aerobic (AO) treatment tank consists of an anoxic tank and an aerobic tank, respectively. Both aerobic tanks are equipped with biological contact oxidation packing. Aeration heads are installed at the bottom of the anoxic tank within the two-stage anoxic-aerobic (AO) treatment tank. A first sludge return pipe is installed at the bottom of the aerobic tank within the first-stage anoxic-aerobic tank, connecting to both the anoxic tank and the anaerobic treatment tank. A second sludge return pipe is installed at the bottom of the aerobic tank within the second-stage anoxic-aerobic tank, connecting to the anoxic tank within the second-stage anoxic-aerobic tank.

6. The high-efficiency wastewater treatment system according to claim 1 or 5, characterized in that, The primary coagulation sedimentation tank and the secondary coagulation sedimentation tank each include a coagulation tank, a flocculation tank, and an inclined tube sedimentation tank that are sequentially separated by baffles and connected by a flow deflector. A third agent pipeline is provided on the coagulation tank, and a fourth agent pipeline is provided on the flocculation tank. The third agent pipeline is connected to a coagulant storage tank for adding coagulant solution, and the fourth agent pipeline is connected to a flocculant storage tank for adding flocculant solution. Hexagonal honeycomb inclined tube packing is provided in the inclined tube sedimentation tank. A third sludge return pipeline is provided at the bottom of the inclined tube sedimentation tank of the secondary coagulation sedimentation tank. The third sludge return pipeline is connected from the bottom to the anoxic tank-aerobic tank of the two-stage anoxic-aerobic (AO) treatment tank.

7. The high-efficiency wastewater treatment system according to claim 1, characterized in that, A primary pH adjustment tank is provided between the wet oxidation pretreatment unit and the Fenton pretreatment tank, and a secondary pH adjustment tank is provided between the Fenton pretreatment tank and the primary coagulation sedimentation tank. A fifth and a sixth reagent pipeline are provided in the primary pH adjustment tank, and a seventh and an eighth reagent pipeline are provided in the secondary pH adjustment tank. The fifth and seventh reagent pipelines are connected to an alkali storage tank for adding alkali, and the sixth and eighth reagent pipelines are connected to an acid storage tank for adding acid.

8. The high-efficiency wastewater treatment system according to claim 7, characterized in that, The equalization tank, the high-temperature and high-pressure oxidation reactor of the wet oxidation pretreatment unit, the primary pH equalization tank, the Fenton pretreatment tank, and the secondary pH equalization tank are all equipped with stirring devices. Each of the two aerobic tanks in the primary pH equalization tank, the Fenton pretreatment tank, the secondary pH equalization tank, the two-stage coagulation sedimentation tank, and the two-stage anoxic-aerobic (AO) treatment tank is equipped with a sludge discharge pipeline at the bottom of each tank. Each sludge discharge pipeline is connected to the sludge tank. Each sludge discharge pipeline is equipped with a sludge discharge pipeline valve and a sludge discharge pump. Each chemical agent pipeline is equipped with a chemical agent pipeline valve and a chemical agent pump.

9. The high-efficiency wastewater treatment system according to claim 8, characterized in that, It also includes a microcomputer control system, which is electrically connected to the power supply device and to each stirring device, each sludge discharge pipeline valve, each sludge discharge pump, each chemical pipeline valve and each chemical pump, and controls their opening and closing.

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