Salt-containing sewage treatment and recycling system

Abstract

The utility model relates to a salt-containing sewage treatment and recycling system which comprises a first treatment subsystem and a second treatment subsystem, the first treatment subsystem comprises a first catalytic oxidation device, a first biological aerated filter, a first filtering device and a double-membrane treatment device which are connected in sequence; the second treatment subsystem comprises a second catalytic oxidation device, a second biological aerated filter and a second filtering device which are communicated in sequence; a sewage inlet of the first treatment subsystem is connected with an inlet of the first catalytic oxidation device, a fresh water outlet of the double-membrane treatment device is connected with a fresh water outlet of the first treatment subsystem, and a concentrated water outlet of the double-membrane treatment device is communicated with a water inlet of the second treatment subsystem; and a water outlet of the second filtering device is connected with a standard-reaching concentrated water outlet of the second treatment subsystem. According to the system disclosed by the invention, the sewage recycling rate and the treatment effect of a refinery enterprise can be improved, recycled water is free of tail gas pollution, and the operation cycle of the double-membrane treatment device is long.

Description

Technical Field

[0001] The present disclosure relates to the field of sewage treatment, and specifically, to a system for treating and recycling saline sewage. Background Art

[0002] To promote industrial water conservation and pollution reduction, implement enterprise water-saving transformation, promote the recycling of water within enterprises, and improve the reuse rate, each subordinate enterprise needs to carry out end-of-pipe reuse water-saving transformation, strengthen the management and upgrading of sewage treatment and reuse facilities, increase the amount of recycled sewage, and all refinery sewage and low-salt sewage should be recycled. Deep desalination and recycling of high-salt sewage in water-scarce areas are encouraged.

[0003] To further conserve precious water resources and reduce sewage discharge, and fulfill the social responsibilities of large-scale refinery central enterprises, many refining enterprises desalinate and recycle saline sewage as makeup water for the circulating water system to further reduce the total water consumption and total sewage discharge of enterprises, and optimize the transformation of urban green enterprises with intrinsic safety and ultra-clean production.

[0004] Existing deep desalination and recycling processes after secondary biochemical treatment of saline sewage mostly adopt a recycling process combining ozone and dual membranes. With the continuous development of sewage treatment and sewage recycling, refractory COD accumulates continuously, and the problem that the ozone oxidation technology has poor COD removal effect becomes more and more prominent. The B / C ratio of the concentrated water after dual membrane treatment is low, and it is difficult to oxidize and treat COD. There is a risk that the organic matter in the discharged water does not meet the standards. At the same time, there are also problems such as ozone tail gas pollution and low efficiency and high energy consumption of ozone generators. It is necessary to develop new refining sewage treatment and recycling technologies to improve the sewage recycling rate of refining enterprises. Summary of the Utility Model

[0005] The purpose of the present disclosure is to provide a system for treating and recycling saline sewage, which can improve the sewage recycling rate and sewage treatment effect of refining enterprises, and the recycled water has no tail gas pollution, and the operation period of the dual membrane treatment device is long.

[0006] To achieve the above purpose, the present disclosure provides a system for treating and recycling saline sewage, the system includes a first treatment subsystem and a second treatment subsystem, the first treatment subsystem includes a first catalytic oxidation device, a first biological aerated filter, a first filtration device and a dual membrane treatment device connected in sequence, and the second treatment subsystem includes a second catalytic oxidation device, a second biological aerated filter and a second filtration device connected in communication sequence;

[0007] The sewage inlet of the first treatment subsystem is connected to the inlet of the first catalytic oxidation device, the fresh water outlet of the dual membrane treatment device is connected to the fresh water outlet of the first treatment subsystem, and the concentrated water outlet of the dual membrane treatment device is communicated with the water inlet of the second treatment subsystem; the water outlet of the second filtration device is connected to the qualified concentrated water outlet of the second treatment subsystem.

[0008] Optionally, the first catalytic oxidation device includes a first mixing and acid-adjusting tank, a first catalytic oxidation reaction tank, a first neutralization tank, and a first coagulation and sedimentation tank that are connected in sequence;

[0009] The water inlet of the first mixing and acid-adjusting tank is formed as the sewage inlet of the first treatment subsystem, and the clear liquid outlet of the first coagulation and sedimentation tank is connected to the water inlet of the first biological aerated filter.

[0010] Optionally, the first mixing and acid-adjusting tank is provided with a first pH sensing unit, a first automatic acid adding unit, and a first mixing unit; the first pH sensing unit is signal-connected to the first automatic acid adding unit to control the acid adding amount of the first automatic acid adding unit according to the pH value detected by the first pH sensing unit; the first mixing unit includes a first stirring module, a first catalyst dissolving module, and a first chemical adding module, and the first stirring module is used to mix the materials in the first mixing unit;

[0011] The first catalytic oxidation reaction tank is provided with a first oxidant dissolving unit, a second chemical adding unit, and a second stirring unit;

[0012] The first neutralization tank is provided with a second pH sensing unit, a first automatic alkali adding unit, a first alkali agent dissolving unit, and a third stirring unit; the second pH sensing unit is signal-connected to the first automatic alkali adding unit to control the alkali adding amount of the first automatic alkali adding unit according to the pH value detected by the second pH sensing unit; the third stirring unit is used to dissolve the materials in the first alkali agent dissolving unit;

[0013] The lower part of the first coagulation and sedimentation tank is formed into a cone shape to discharge the sludge after solid-liquid separation in the first coagulation and sedimentation tank from the lower sludge discharge port.

[0014] Optionally, the clear liquid outlet of the coagulation and sedimentation tank is connected to the water inlet of the first biological aerated filter; the first biological aerated filter is filled with a carbon-based carrier.

[0015] Optionally, the first filtering device is a manganese sand filtering device, and the manganese sand filtering device is provided with manganese sand fillers.

[0016] Optionally, the dual-membrane treatment device includes a ultrafiltration unit, a security filter, and a reverse osmosis unit that are connected in sequence;

[0017] The water outlet of the first filtration device is connected to the water inlet of the ultrafiltration unit, the water outlet of the ultrafiltration unit is connected to the water inlet of the security filter, the water outlet of the security filter is connected to the water inlet of the reverse osmosis unit, the fresh water outlet of the reverse osmosis unit is connected to the fresh water outlet of the first treatment subsystem, and the concentrated water outlet of the reverse osmosis unit is connected to the water inlet of the second treatment subsystem.

[0018] Optionally, the second catalytic oxidation device includes a second mixing and acid adjustment tank, a second catalytic oxidation reaction tank, a second neutralization tank, and a second coagulation and sedimentation tank that are connected in sequence;

[0019] The water inlet of the second mixing and acid adjustment tank is formed as the water inlet of the second treatment subsystem, and the clear liquid outlet of the second coagulation and sedimentation tank is communicated with the water inlet of the second biological aerated filter.

[0020] Optionally, the second mixing and acid adjustment tank is provided with a third pH sensing unit, a second automatic acid addition unit, and a fourth mixing unit; the third pH sensing unit is signal-connected to the second automatic acid addition unit to control the acid addition amount of the second automatic acid addition unit according to the pH value detected by the third pH sensing unit; the fourth mixing unit includes a second catalyst dissolution module, a third chemical addition module, and a fourth stirring module, and the fourth stirring module is used to mix the materials in the fourth mixing unit;

[0021] The second catalytic oxidation reaction tank is provided with a second oxidant dissolution unit, a fourth chemical addition unit, and a fifth stirring unit;

[0022] The second neutralization tank is provided with a fourth pH sensing unit, a second automatic alkali addition unit, a second alkali agent dissolution unit, and a sixth stirring unit; the fourth pH sensing unit is signal-connected to the second automatic alkali addition unit to control the alkali addition amount of the second automatic alkali addition unit according to the pH value detected by the fourth pH sensing unit; the sixth stirring unit is used to dissolve the materials in the second alkali agent dissolution unit;

[0023] The lower part of the second coagulation and sedimentation tank is conical, and is used to discharge the sludge after solid-liquid separation of the materials in the second coagulation and sedimentation tank from the lower sludge discharge port.

[0024] Optionally, the clear liquid outlet of the second coagulation and sedimentation tank is connected to the water inlet of the second biological aerated filter;

[0025] The second biological aerated filter is filled with a carbon-based carrier.

[0026] Optionally, the water outlet of the second filtration device is connected to the qualified concentrated water outlet of the second treatment subsystem;

[0027] The second filtering device is a sand filtering device, and quartz sand filler is arranged in the sand filtering device;

[0028] The system further includes a circulating water subsystem, and the fresh water outlet of the first treatment subsystem is communicated with the inlet of the circulating water subsystem.

[0029] Through the above technical solution, the salt-containing sewage treatment and reuse system of the present disclosure includes a first treatment subsystem and a second treatment subsystem. After the first treatment subsystem deeply treats the salt-containing sewage through a first catalytic oxidation device, a first biological aerated filter, a first filtering device and a dual-membrane treatment device, fresh water for reuse, circulating water and concentrated water are obtained. Then, the concentrated water is secondary-treated through a second catalytic oxidation device, a second biological aerated filter and a second filtering device of the second treatment subsystem, and the concentrated water is discharged after meeting the standards. The system of the present disclosure can improve the sewage reuse rate and sewage treatment effect of refining enterprises. The reused water of the present disclosure has no tail gas pollution, and the operation cycle of the dual-membrane treatment device is long.

[0030] Other features and advantages of the present disclosure will be described in detail in the subsequent specific implementation part. Description of the Drawings

[0031] The drawings are used to provide a further understanding of the present disclosure, and constitute a part of the specification. Together with the following specific implementation, they are used to explain the present disclosure, but do not constitute a limitation to the present disclosure. In the drawings:

[0032] Figure 1 It is a schematic diagram of the system of Embodiment 1 of the present disclosure.

[0033] Description of the Reference Numerals in the Drawings

[0034] 1: First catalytic oxidation device; 2: First biological aerated filter; 3: First filtering device; 4: Dual-membrane treatment device; 5: Second catalytic oxidation device; 6: Second biological aerated filter; 7: Second filtering device; 1-1: First mixing and acid-adjusting tank; 1-2: First catalytic oxidation reaction tank; 1-3: First neutralization tank; 1-4: First coagulation sedimentation tank; 4-1: Ultrafiltration unit; 4-2: Security filter; 4-3: Reverse osmosis unit; 5-1: Second mixing and acid-adjusting tank; 5-2: Second catalytic oxidation reaction tank; 5-3: Second neutralization tank; 5-4: Second coagulation sedimentation tank;

[0035] G1: Sewage inlet of the first treatment subsystem; G2: Fresh water outlet of the first treatment subsystem; G3: Up-to-standard concentrated water outlet of the second treatment subsystem. Specific Implementation

[0036] The following will describe in detail the specific embodiments of the present disclosure with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present disclosure, and are not intended to limit the present disclosure.

[0037] The present disclosure provides a system for treating and recycling saline wastewater, as Figure 1 shown. The system includes a first treatment subsystem and a second treatment subsystem. The first treatment subsystem includes a first catalytic oxidation device 1, a first biological aerated filter 2, a first filtration device 3, and a dual-membrane treatment device 4 connected in sequence. The second treatment subsystem includes a second catalytic oxidation device 5, a second biological aerated filter 6, and a second filtration device 7 connected in sequence and in communication.

[0038] The sewage inlet G1 of the first treatment subsystem is connected to the inlet of the first catalytic oxidation device 1. The fresh water outlet of the dual-membrane treatment device 4 is connected to the fresh water outlet G2 of the first treatment subsystem. The concentrated water outlet of the dual-membrane treatment device 4 is in communication with the inlet of the second treatment subsystem. The water outlet of the second filtration device 7 is connected to the qualified concentrated water outlet G3 of the second treatment subsystem.

[0039] The saline wastewater treatment and recycling system of the present disclosure includes a first treatment subsystem and a second treatment subsystem. After the first treatment subsystem deeply treats the saline wastewater through the first catalytic oxidation device, the first biological aerated filter, the first filtration device, and the dual-membrane treatment device, fresh water for recycling and concentrated water are obtained. Then, the concentrated water is secondary-treated through the second catalytic oxidation device, the second biological aerated filter, and the second filtration device of the second treatment subsystem, and the concentrated water is discharged after reaching the standard. The system of the present disclosure can improve the sewage recycling rate and sewage treatment effect of refineries. The recycled water of the present disclosure has no tail gas pollution, and the dual-membrane treatment device has a long operation cycle.

[0040] The iron ion content in the circulating cooling water is relatively high, which will cause corrosion of the water cooler system. Theoretically, it is required that the Fe in the circulating water after reaching the concentration multiple 3+The concentration is below 1.0 mg / L. In this application, a first filtration device is connected after the first catalytic oxidation device and the first biological aerated filter to remove iron ions in the water, further catalytically oxidize the remaining organic matter in the water, disinfect and deodorize the water, and remove microorganisms in the water, ensuring that the water quality entering the dual-membrane treatment device is qualified, and eliminating the influence of the remaining iron ions in the first catalytic oxidation device on the makeup water for the fresh water reuse circulating water. Through the above treatment, the efficient operation of the dual-membrane treatment device and the qualification of iron ions in the fresh water used for makeup water of the circulating water are ensured, thereby greatly reducing the consumption of fresh water and improving the sewage reuse rate of the refining enterprise. Further, the concentrated water after the dual-membrane treatment device has characteristics such as a high salt content and a low BOD5 / COD ratio of organic matter. Using conventional ozone oxidation to reduce COD has poor effects. In this application, the dual-membrane concentrated water is treated by using a second catalytic oxidation device, a second biological aerated filter, and a second filtration device, and the treatment effect is excellent, making the indicators of the discharged water stable and up to standard.

[0041] According to an embodiment of the present disclosure, the first catalytic oxidation device 1 includes a first mixing and acid-adjusting tank 1-1, a first catalytic oxidation reaction tank 1-2, a first neutralization tank 1-3, and a first coagulation and sedimentation tank 1-4 that are sequentially connected; the water inlet of the first mixing and acid-adjusting tank 1-1 is formed as the sewage inlet G1 of the first treatment subsystem, and the clear liquid outlet of the first coagulation and sedimentation tank is communicated with the water inlet of the first biological aerated filter 2.

[0042] According to an embodiment of the present disclosure, the first mixing and acid-adjusting tank 1-1 is provided with a first pH sensing unit, a first automatic acid addition unit, and a first mixing unit; the first pH sensing unit is signal-connected to the first automatic acid addition unit to control the acid addition amount of the first automatic acid addition unit according to the pH value detected by the first pH sensing unit; the first mixing unit includes a first stirring module, a first catalyst dissolution module, and a first medicine addition module, and the first stirring module is used to mix the materials in the first mixing unit. In a further embodiment, the pH of the first mixing and acid-adjusting tank is 2.5 to 5.0, and the reaction time of the saline sewage in the first mixing and acid-adjusting tank is 5 to 20 min; the acid agent used in the first automatic acid addition unit can be an inorganic acid, such as one or more selected from dilute sulfuric acid, hydrochloric acid, and phosphoric acid, preferably dilute sulfuric acid, and the concentration of the dilute sulfuric acid can be 5% to 20%; the first catalyst dissolution module is equipped with a catalyst dissolution tank, and the catalyst used is a ferrous salt, preferably a ferrous sulfate solution with a mass concentration of 10% to 25%; the first medicine addition module is used to add the catalyst; the first stirring module can be one or more of hydraulic stirring, mechanical stirring, and air stirring, preferably mechanical stirring.

[0043] According to an embodiment of the present disclosure, the first catalytic oxidation reaction tank 1-2 is provided with a first oxidant dissolution unit, a second chemical dosing unit, and a second stirring unit. In a further embodiment, the oxidant used in the first oxidant dissolution unit can be one or more of hydrogen peroxide, hypochlorite, and persulfate, preferably hydrogen peroxide; the dosing mass of the oxidant can be determined according to the COD of the saline wastewater, and the ratio of the dosing mass of the oxidant to the COD of the saline wastewater is 0.25-3:1, and the ratio of the dosing mass of the catalyst to the dosing mass of the oxidant is 1-8:1; the reaction time of the saline wastewater in the first catalytic oxidation reaction tank is 0.5-4 h, preferably 0.8-2 h; the second chemical dosing unit is used to add the oxidant; the second stirring unit can be one or more of hydraulic stirring, mechanical stirring, and air stirring, preferably mechanical stirring.

[0044] According to an embodiment of the present disclosure, the first neutralization tank 1-3 is provided with a second pH sensing unit, a first automatic alkali addition unit, a first alkali agent dissolution unit, and a third stirring unit; the second pH sensing unit is signal-connected to the first automatic alkali addition unit to control the alkali addition amount of the first automatic alkali addition unit according to the pH value detected by the second pH sensing unit; the third stirring unit is used to dissolve the materials in the first alkali agent dissolution unit; the third stirring unit can be one or more of hydraulic stirring, mechanical stirring, and air stirring, preferably mechanical stirring. In a further embodiment, the alkali agent used in the first automatic alkali addition unit can be an inorganic alkali, such as sodium hydroxide; the reaction time of the saline wastewater in the first neutralization tank is 5-20 min.

[0045] According to an embodiment of the present disclosure, the lower part of the first coagulation sedimentation tank 1-4 is formed in a conical shape for discharging the sludge after solid-liquid separation in the first coagulation sedimentation tank from the lower sludge discharge port; in a further embodiment, the reaction time of the saline wastewater in the first coagulation sedimentation tank is 2-4 h.

[0046] According to an embodiment of the present disclosure, the clear liquid outlet of the first coagulation sedimentation tank is connected to the water inlet of the first biological aerated filter 2; the first biological aerated filter 2 is filled with a carbon-based carrier. In a further embodiment, the particle size of the carbon-based carrier can be 0.5-1 mm, the iodine value is 700-900 g / g, and the bulk density is 0.4-0.6 g / L; air is introduced into the first biological aerated filter 2 through the air inlet and the aeration device at the bottom to maintain the growth of microorganisms loaded on the carbon-based filler, which is beneficial to the removal of organic matter in the wastewater by the microorganisms on the filler.

[0047] According to an embodiment of the present disclosure, the first filtration device 3 is a manganese sand filtration device, and the manganese sand filtration device is provided with manganese sand filler. The above embodiment is beneficial to removing suspended solids and iron ions in the wastewater.

[0048] According to an embodiment of the present disclosure, the dual-membrane treatment device 4 includes an ultrafiltration unit 4-1, a security filter 4-2, and a reverse osmosis unit 4-3 connected in sequence; the water outlet of the first filtration device 3 is connected to the water inlet of the ultrafiltration unit 4-1, the water outlet of the ultrafiltration unit 4-1 is connected to the water inlet of the security filter 4-2, the water outlet of the security filter 4-2 is connected to the water inlet of the reverse osmosis unit 4-3, the fresh water outlet of the reverse osmosis unit 4-3 is connected to the fresh water outlet G2 of the first treatment subsystem, and the concentrated water outlet of the reverse osmosis unit 4-3 is connected to the water inlet of the second treatment subsystem.

[0049] According to an embodiment of the present disclosure, the second catalytic oxidation device 5 includes a second mixing and acid-adjusting tank 5-1, a second catalytic oxidation reaction tank 5-2, a second neutralization tank 5-3, and a second coagulation and sedimentation tank 5-4 connected in sequence; the water inlet of the second mixing and acid-adjusting tank 5-1 is formed as the water inlet of the second treatment subsystem, and the clear liquid outlet of the second coagulation and sedimentation tank is communicated with the water inlet of the second biological aerated filter 6.

[0050] According to an embodiment of the present disclosure, the second mixing and acid-adjusting tank 5-1 is provided with a third pH sensing unit, a second automatic acid addition unit, and a fourth mixing unit; the third pH sensing unit is in signal connection with the second automatic acid addition unit and is used to control the acid addition amount of the second automatic acid addition unit according to the pH value detected by the third pH sensing unit; the fourth mixing unit includes a second catalyst dissolution module, a third chemical addition module, and a fourth stirring module, and the fourth stirring module is used to mix the materials in the fourth mixing unit. In a further embodiment, the pH of the second mixing and acid-adjusting tank is 2.5 to 5.0, and the reaction time of the saline wastewater in the second mixing and acid-adjusting tank is 5 to 20 minutes; the acid agent used by the second automatic acid addition unit can be an inorganic acid, such as one or more selected from dilute sulfuric acid, hydrochloric acid, and phosphoric acid, preferably dilute sulfuric acid, and the concentration of the dilute sulfuric acid can be 5% to 20%; the second catalyst dissolution module is equipped with a catalyst dissolution tank, and the catalyst used is a ferrous salt, preferably a ferrous sulfate solution with a mass concentration of 10% to 25%, and the third chemical addition module is used to add the catalyst; the fourth stirring module can be one or more of hydraulic stirring, mechanical stirring, and air stirring, preferably mechanical stirring.

[0051] According to an embodiment of the present disclosure, the second catalytic oxidation reaction tank 5-2 is provided with a second oxidant dissolution unit, a fourth chemical dosing unit, and a fifth stirring unit. In a further embodiment, the oxidant used in the second oxidant dissolution unit can be one or more of hydrogen peroxide, hypochlorite, and persulfate, preferably hydrogen peroxide; the dosing mass of the oxidant can be determined according to the COD of the saline wastewater, and the ratio of the dosing mass of the oxidant to the COD of the saline wastewater is 0.25-3:1, and the ratio of the dosing mass of the catalyst to the dosing mass of the oxidant is 1-8:1; the reaction time of the saline wastewater in the second catalytic oxidation reaction tank is 0.5-4 h, preferably 0.8-2 h; the fourth chemical dosing unit is used to add the oxidant; the fifth stirring unit can be one or more of hydraulic stirring, mechanical stirring, and air stirring, preferably mechanical stirring.

[0052] According to an embodiment of the present disclosure, the second neutralization tank 5-3 is provided with a fourth pH sensing unit, a second automatic alkali addition unit, a second alkali agent dissolution unit, and a sixth stirring unit; the fourth pH sensing unit is signal-connected to the second automatic alkali addition unit for controlling the alkali addition amount of the second automatic alkali addition unit according to the pH value detected by the fourth pH sensing unit; the sixth stirring unit is used to dissolve the materials in the second alkali agent dissolution unit; the sixth stirring unit can be one or more of hydraulic stirring, mechanical stirring, and air stirring, preferably mechanical stirring. In a further embodiment, the alkali agent used in the second automatic alkali addition unit can be an inorganic alkali, for example, it can be sodium hydroxide; the reaction time of the saline wastewater in the first neutralization tank is 5-20 min.

[0053] According to an embodiment of the present disclosure, the lower part of the second coagulation sedimentation tank 5-4 is conical, which is used to discharge the sludge after solid-liquid separation of the materials in the second coagulation sedimentation tank from the lower sludge discharge port; in a further embodiment, the reaction time of the saline wastewater in the second coagulation sedimentation tank is 2-4 h.

[0054] According to an embodiment of the present disclosure, the clear liquid outlet of the second coagulation sedimentation tank is connected to the water inlet of the second biological aerated filter 6; the second biological aerated filter 6 is filled with a carbon-based carrier. In a further embodiment, the particle size of the carbon-based carrier can be 0.5-1 mm, the iodine value is 700-900 g / g, and the bulk density is 0.4-0.6 g / L; air is introduced into the first biological aerated filter 2 through the air inlet and the aeration device at the bottom to maintain the growth of the microorganisms loaded on the carbon-based packing, which is beneficial to the removal of organic matter in the wastewater by the microorganisms on the packing.

[0055] According to an embodiment of the present disclosure, the water outlet of the second filtering device 7 is connected to the qualified concentrated water outlet G3 of the second treatment subsystem; the second filtering device 7 is a sand filtering device, and quartz sand fillers are arranged in the sand filtering device. The above embodiment is beneficial to removing suspended solids in the saline wastewater.

[0056] According to an embodiment of the present disclosure, the system further includes a circulating water subsystem, and the fresh water outlet G2 of the first treatment subsystem is communicated with the inlet of the circulating water subsystem. The above embodiment reduces the consumption of fresh water, is beneficial to saving energy consumption, and improves the sewage reuse rate.

[0057] The present disclosure will be further described below through examples, but the present disclosure is not limited thereby.

[0058] Example 1

[0059] As Figure 1 shown, the saline wastewater treatment and reuse system of this Example 1 includes a first treatment subsystem and a second treatment subsystem. The first treatment subsystem includes a first catalytic oxidation device 1, a first biological aerated filter 2, a first filtering device 3, and a dual-membrane treatment device 4 connected in sequence. The second treatment subsystem includes a second catalytic oxidation device 5, a second biological aerated filter 6, and a second filtering device 7 connected in sequence;

[0060] The sewage inlet G1 of the first treatment subsystem is connected to the inlet of the first catalytic oxidation device 1. The fresh water outlet of the dual-membrane treatment device 4 is connected to the fresh water outlet G2 of the first treatment subsystem. The concentrated water outlet of the dual-membrane treatment device 4 is communicated with the water inlet of the second treatment subsystem; the water outlet of the second filtering device 7 is connected to the qualified concentrated water outlet G3 of the second treatment subsystem; the system of this embodiment further includes a circulating water subsystem, and the fresh water outlet G2 of the first treatment subsystem is communicated with the inlet of the circulating water subsystem;

[0061] The first catalytic oxidation device 1 includes a first mixing and acid - adjusting tank 1 - 1, a first catalytic oxidation reaction tank 1 - 2, a first neutralization tank 1 - 3, and a first coagulation and sedimentation tank 1 - 4 that are connected in sequence; the water inlet of the first mixing and acid - adjusting tank 1 - 1 is formed as the sewage inlet G1 of the first treatment subsystem, and the clear liquid outlet of the first coagulation and sedimentation tank is connected to the water inlet of the first biological aerated filter 2; the first mixing and acid - adjusting tank 1 - 1 is provided with a first pH sensing unit, a first automatic acid - adding unit, and a first mixing unit; the first pH sensing unit is signal - connected to the first automatic acid - adding unit to control the acid - adding amount of the first automatic acid - adding unit according to the pH value detected by the first pH sensing unit; the acid agent used by the first automatic acid - adding unit is dilute sulfuric acid with a concentration of 20%; the first mixing unit includes a first stirring module, a first catalyst dissolution module, and a first chemical - adding module; the catalyst added by the first chemical - adding module is ferrous sulfate salt with a mass concentration of 25%.

[0062] The first catalytic oxidation reaction tank 1 - 2 is provided with a first oxidant dissolution unit, a second chemical - adding unit, and a second stirring unit; the first neutralization tank 1 - 3 is provided with a second pH sensing unit, a first automatic alkali - adding unit, a first alkali agent dissolution unit, and a third stirring unit; the second pH sensing unit is signal - connected to the first automatic alkali - adding unit to control the alkali - adding amount of the first automatic alkali - adding unit according to the pH value detected by the second pH sensing unit; the oxidant added by the second chemical - adding unit is hydrogen peroxide; the lower part of the first coagulation and sedimentation tank 1 - 4 is formed in a conical shape to enable the sludge after solid - liquid separation in the first coagulation and sedimentation tank to be discharged from the lower sludge discharge port; the clear liquid outlet of the first coagulation and sedimentation tank is connected to the water inlet of the first biological aerated filter 2; the first biological aerated filter 2 is filled with a carbon - based carrier; the first filtering device 3 is a manganese sand filtering device, and the manganese sand filtering device is provided with manganese sand filler; the double - membrane treatment device 4 includes a ultrafiltration unit 4 - 1, a security filter 4 - 2, and a reverse osmosis unit 4 - 3 that are connected in sequence; the water outlet of the first filtering device 3 is connected to the water inlet of the ultrafiltration unit 4 - 1, the water outlet of the ultrafiltration unit 4 - 1 is connected to the water inlet of the security filter 4 - 2, the water outlet of the security filter 4 - 2 is connected to the water inlet of the reverse osmosis unit 4 - 3, the fresh water outlet of the reverse osmosis unit 4 - 3 is connected to the fresh water outlet G2 of the first treatment subsystem, and the concentrated water outlet of the reverse osmosis unit 4 - 3 is connected to the water inlet of the second treatment subsystem;

[0063] The second catalytic oxidation device 5 includes a second mixing and acid - adjusting tank 5 - 1, a second catalytic oxidation reaction tank 5 - 2, a second neutralization tank 5 - 3, and a second coagulation and sedimentation tank 5 - 4 that are connected in sequence; the water inlet of the second mixing and acid - adjusting tank 5 - 1 is formed as the water inlet of the second treatment subsystem, and the clear liquid outlet of the second coagulation and sedimentation tank is connected to the water inlet of the second biological aerated filter 6;

[0064] The second mixed acid - adjusting tank 5 - 1 is provided with a third pH sensing unit, a second automatic acid - adding unit, and a fourth mixing unit; the third pH sensing unit is signal - connected to the second automatic acid - adding unit to control the acid - adding amount of the second automatic acid - adding unit according to the pH value detected by the third pH sensing unit; the acid agent used by the second automatic acid - adding unit is dilute sulfuric acid with a concentration of 20%; the fourth mixing unit includes a second catalyst dissolving module, a third chemical - adding module, and a fourth stirring module; the catalyst added by the third chemical - adding module is ferrous sulfate salt with a mass concentration of 25%; the second catalytic oxidation reaction tank 5 - 2 is provided with a second oxidant dissolving unit, a fourth chemical - adding unit, and a fifth stirring unit; the oxidant added by the fourth chemical - adding unit is hydrogen peroxide; the second neutralization tank 5 - 3 is provided with a fourth pH sensing unit, a second automatic alkali - adding unit, a second alkali agent dissolving unit, and a sixth stirring unit; the fourth pH sensing unit is signal - connected to the second automatic alkali - adding unit to control the alkali - adding amount of the second automatic alkali - adding unit according to the pH value detected by the fourth pH sensing unit; the lower part of the second coagulation sedimentation tank 5 - 4 is conical, used for discharging the sludge of the materials in the second coagulation sedimentation tank after solid - liquid separation from the lower sludge discharge port; the clear liquid outlet of the second coagulation sedimentation tank is connected to the water inlet of the second biological aerated filter 6; the second biological aerated filter 6 is filled with a carbon - based carrier; the water outlet of the second filtering device 7 is connected to the up - to - standard concentrated water outlet G3 of the second treatment subsystem; the second filtering device 7 is a sand - filtering device, and quartz sand fillers are arranged in the sand - filtering device.

[0065] Use HJ / T345 - 2007 "Phenanthroline Spectrophotometry" to measure the concentration of iron ions at the fresh - water outlet G2. After detection, the concentration of iron ions at the fresh - water outlet G2 is less than 0.1mg / L, meeting the inlet requirement for circulating water make - up water (the concentration of iron ions is less than 0.5mg / L).

[0066] Use GB11914 - 89 "Water Quality - Determination of Chemical Oxygen Demand - Potassium Dichromate Method" to measure the COD content of the discharged water at the water outlet of the second treatment subsystem. The measured COD content at the water outlet G3 of the second treatment subsystem is 35 - 45mg / L, meeting the COD discharge index of the discharged water (the content of COD is less than 60mg / L).

[0067] Comparative Example 1

[0068] This comparative example is the same as Example 1, except that the system of Comparative Example 1 does not include the first filtering device 3 and the second catalytic oxidation device 5.

[0069] The mass concentration of iron ions at the freshwater outlet G2 measured using HJ / T 345-2007 "Phenanthroline Spectrophotometry" is 0.8 mg / L, which does not meet the inlet requirement that the iron ion concentration in the recycled water make-up is less than 0.5 mg / L.

[0070] The COD mass concentration of the external drainage at the outlet G3 of the second treatment subsystem measured using GB 11914-89 "Water Quality - Determination of Chemical Oxygen Demand - Potassium Dichromate Method" is 100 - 120 mg / L, which does not meet the discharge standard that the external drainage COD is less than 60 mg / L.

[0071] It can be seen from the comparison between Example 1 and Comparative Example 1 that the system of the present disclosure can improve the sewage reuse rate and sewage treatment effect of refineries. The reclaimed water of the present disclosure has no tail gas pollution, and the operation cycle of the dual - membrane treatment device is long.

[0072] The preferred embodiments of the present disclosure have been described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details in the above - mentioned embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0073] In addition, it should be noted that, among the various specific technical features described in the above - mentioned specific embodiments, they can be combined in any suitable way without conflict. To avoid unnecessary repetition, the present disclosure does not explain various possible combination methods separately.

[0074] In addition, any combination can be made between various different embodiments of the present disclosure, as long as it does not violate the idea of the present disclosure, and it should also be regarded as the content disclosed by the present disclosure.

Claims

1. A salt-containing sewage treatment and reuse system, characterized in that, The system includes a first processing subsystem and a second processing subsystem. The first processing subsystem includes a first catalytic oxidation device (1), a first biological aerated filter (2), a first filtering device (3), and a dual-membrane treatment device (4) connected in sequence. The second processing subsystem includes a second catalytic oxidation device (5), a second biological aerated filter (6), and a second filtering device (7) connected in communication sequence; The sewage inlet (G1) of the first processing subsystem is connected to the inlet of the first catalytic oxidation device (1). The fresh water outlet of the dual-membrane treatment device (4) is connected to the fresh water outlet (G2) of the first processing subsystem. The concentrated water outlet of the dual-membrane treatment device (4) is communicated with the water inlet of the second processing subsystem. The water outlet of the second filtering device (7) is connected to the qualified concentrated water outlet (G3) of the second processing subsystem.

2. The system according to claim 1, characterized in that, The first catalytic oxidation device (1) includes a first mixing and acid-adjusting tank (1-1), a first catalytic oxidation reaction tank (1-2), a first neutralization tank (1-3), and a first coagulation and sedimentation tank (1-4) connected in communication sequence; The water inlet of the first mixing and acid-adjusting tank (1-1) is formed as the sewage inlet (G1) of the first processing subsystem. The clear liquid outlet of the first coagulation and sedimentation tank is communicated with the water inlet of the first biological aerated filter (2).

3. The system according to claim 2, wherein The first mixing and acid-adjusting tank (1-1) is provided with a first pH sensing unit, a first automatic acid addition unit, and a first mixing unit. The first pH sensing unit is signal-connected to the first automatic acid addition unit to control the acid addition amount of the first automatic acid addition unit according to the pH value detected by the first pH sensing unit. The first mixing unit includes a first stirring module, a first catalyst dissolution module, and a first chemical addition module. The first stirring module is used to mix the materials in the first mixing unit; The first catalytic oxidation reaction tank (1-2) is provided with a first oxidant dissolution unit, a second chemical addition unit, and a second stirring unit; The first neutralization tank (1-3) is provided with a second pH sensing unit, a first automatic alkali addition unit, a first alkali agent dissolution unit, and a third stirring unit. The second pH sensing unit is signal-connected to the first automatic alkali addition unit to control the alkali addition amount of the first automatic alkali addition unit according to the pH value detected by the second pH sensing unit. The third stirring unit is used to dissolve the materials in the first alkali agent dissolution unit; The lower part of the first coagulation and sedimentation tank (1-4) is formed in a conical shape to discharge the sludge after solid-liquid separation in the first coagulation and sedimentation tank from the lower sludge discharge port.

4. The system according to claim 3, wherein The clear liquid outlet of the coagulation and sedimentation tank is connected to the water inlet of the first biological aerated filter (2). The first biological aerated filter (2) is filled with a carbon-based carrier.

5. The system according to claim 1, wherein The first filtering device (3) is a manganese sand filtering device, and the manganese sand filtering device is provided with manganese sand fillers.

6. The system according to claim 1, wherein The dual-membrane treatment device (4) includes an ultrafiltration unit (4-1), a security filter (4-2), and a reverse osmosis unit (4-3) connected in sequence; The water outlet of the first filtering device (3) is connected to the water inlet of the ultrafiltration unit (4-1), the water outlet of the ultrafiltration unit (4-1) is connected to the water inlet of the security filter (4-2), the water outlet of the security filter (4-2) is connected to the water inlet of the reverse osmosis unit (4-3), the fresh water outlet of the reverse osmosis unit (4-3) is connected to the fresh water outlet (G2) of the first treatment subsystem, and the concentrated water outlet of the reverse osmosis unit (4-3) is connected to the water inlet of the second treatment subsystem.

7. The system according to claim 1, wherein The second catalytic oxidation device (5) includes a second mixing and acid adjusting tank (5-1), a second catalytic oxidation reaction tank (5-2), a second neutralization tank (5-3), and a second coagulation and sedimentation tank (5-4) that are connected in sequence; The water inlet of the second mixing and acid adjusting tank (5-1) is formed as the water inlet of the second treatment subsystem, and the clear liquid outlet of the second coagulation and sedimentation tank is communicated with the water inlet of the second biological aerated filter (6).

8. The system according to claim 7, wherein The second mixing and acid adjusting tank (5-1) is provided with a third pH sensing unit, a second automatic acid adding unit, and a fourth mixing unit; the third pH sensing unit is signal-connected to the second automatic acid adding unit for controlling the acid adding amount of the second automatic acid adding unit according to the pH value detected by the third pH sensing unit; the fourth mixing unit includes a second catalyst dissolving module, a third chemical adding module, and a fourth stirring module, and the fourth stirring module is used for mixing the materials in the fourth mixing unit; The second catalytic oxidation reaction tank (5-2) is provided with a second oxidant dissolving unit, a fourth chemical adding unit, and a fifth stirring unit; The second neutralization tank (5-3) is provided with a fourth pH sensing unit, a second automatic alkali adding unit, a second alkali agent dissolving unit, and a sixth stirring unit; the fourth pH sensing unit is signal-connected to the second automatic alkali adding unit for controlling the alkali adding amount of the second automatic alkali adding unit according to the pH value detected by the fourth pH sensing unit; the sixth stirring unit is used for dissolving the materials in the second alkali agent dissolving unit; The lower part of the second coagulation and sedimentation tank (5-4) is conical, and is used for discharging the sludge after solid-liquid separation of the materials in the second coagulation and sedimentation tank from the lower sludge discharge port.

9. The system according to claim 8, wherein The clear liquid outlet of the second coagulation and sedimentation tank (5-4) is connected to the water inlet of the second biological aerated filter (6); The second biological aerated filter (6) is filled with a carbon-based carrier.

10. The system according to claim 1, characterized in that, The water outlet of the second filtering device (7) is connected to the up-to-standard concentrated water outlet (G3) of the second treatment subsystem; The second filtering device (7) is a sand filtering device, and quartz sand fillers are arranged in the sand filtering device; The system further includes a circulating water subsystem, and the fresh water outlet (G2) of the first treatment subsystem is communicated with the inlet of the circulating water subsystem.

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