A combined treatment system for chemical wastewater and hydrogen peroxide wastewater

Abstract

The present disclosure relates to a chemical wastewater and hydrogen peroxide wastewater combined treatment system, which comprises a chemical wastewater pretreatment unit, a hydrogen peroxide wastewater pretreatment unit, and a catalytic reaction unit and an acid-base neutralization and precipitation unit which are sequentially communicated; wherein the catalytic reaction unit comprises a chemical wastewater inlet and a hydrogen peroxide wastewater inlet; the chemical wastewater inlet is communicated with a chemical wastewater pretreatment outlet of the chemical wastewater pretreatment unit, and the hydrogen peroxide wastewater inlet is communicated with a hydrogen peroxide wastewater pretreatment outlet of the hydrogen peroxide wastewater pretreatment unit. The system uses chemical wastewater and hydrogen peroxide wastewater together, can reduce a part of organic pollutants, improve the wastewater biodegradability, and further greatly reduce the peroxide concentration in the hydrogen peroxide wastewater, realize the treatment of waste by waste, and meet the requirements of entering the sewage treatment plant.

Description

Technical Field

[0001] The present disclosure relates to a chemical wastewater treatment apparatus, and specifically relates to a combined treatment system for chemical wastewater and hydrogen peroxide wastewater. Background Art

[0002] Propylene oxide (PO) is an important propylene derivative, which is widely used in the fields of automobile manufacturing, household goods, food and medicine, construction, aerospace and the like. For example, the special wastewater generated by producing propylene oxide through the HPPO process contains some refractory organic matters and toxic and harmful substances, and the wastewater has extremely poor biodegradability, which brings great difficulties to environmental governance; at the same time, the wastewater generated by the hydrogen peroxide device supporting HPPO contains residual hydrogen peroxide, heavy aromatics and other substances. The high-concentration peroxides contained in the hydrogen peroxide wastewater will cause serious damage to the microbial system, so it cannot be directly discharged into the sewage treatment plant. Therefore, both chemical process wastewater and hydrogen peroxide process wastewater need to be properly pretreated before entering the existing sewage treatment plant of the enterprise.

[0003] For example, in patent CN201810167061.5, organic-containing wastewater and an azeotropic agent are subjected to multi-stage azeotropic rectification, so that heavy components such as propylene glycol and propylene glycol derivatives in the wastewater are recovered, and the difficulty of wastewater treatment is reduced, which provides possibilities for the biochemical treatment of wastewater and the recovery of corresponding by-products.

[0004] The invention of CN202110008628.6 relates to the field of wastewater treatment, and specifically relates to a pretreatment method for wastewater from producing hydrogen peroxide by the anthraquinone process; comprising the steps of phosphorus removal reaction, precipitation, catalytic oxidation reaction and pH value adjustment, etc. Firstly, a calcium salt precipitant is added to precipitate the phosphorus salt in the wastewater, then a small amount of hydrogen peroxide contained in the wastewater is utilized, ferrous salt ions are added to efficiently remove organic pollutants contained in the wastewater under the action of a catalyst, and through the final pH value adjustment, the generated iron ions can be converted into ferric hydroxide precipitate, which functions to flocculate pollutants and further purify the sewage; this method is aimed at the characteristics of the wastewater from producing hydrogen peroxide by the anthraquinone process, and uses existing conditions to pretreat the wastewater, which can create conditions for the subsequent treatment of sewage and reduce the treatment cost.

[0005] Patent CN205974092U discloses a device for pretreating hydrogen peroxide production wastewater to remove phosphorus and organic matters, which includes a hydrogen peroxide wastewater collection tank, a ferrous sulfate tank, a high-concentration wastewater collection tank, a first reaction tank, a second reaction tank, a third reaction tank, a fourth reaction tank, a first sedimentation tank, a second sedimentation tank and a waste lye tank, wherein the wastewater pipeline connected to the liquid inlet of the high-concentration wastewater collection tank introduces wastewater from clay regeneration or catalyst regeneration in the hydrogen peroxide workshop.

[0006] However, current wastewater treatment apparatuses still have the disadvantages of complex equipment construction, low pollutant removal rate and poor targeting property for pollutants. Utility Model Content

[0007] The purpose of this disclosure is to provide a combined treatment system for chemical wastewater and hydrogen peroxide wastewater. This system combines chemical wastewater and hydrogen peroxide wastewater, which can reduce some organic pollutants, improve the biodegradability of wastewater, and significantly reduce the concentration of peroxide in hydrogen peroxide wastewater, achieving "waste treatment with waste" and meeting the requirements for entering a sewage treatment plant.

[0008] To achieve the above objectives, this disclosure provides a combined treatment system for chemical wastewater and hydrogen peroxide wastewater. The system includes a chemical wastewater pretreatment unit, a hydrogen peroxide wastewater pretreatment unit, and a catalytic reaction unit and an acid-base neutralization precipitation unit connected in sequence. The catalytic reaction unit includes a chemical wastewater inlet and a hydrogen peroxide wastewater inlet; the chemical wastewater inlet is connected to the chemical wastewater pretreatment outlet of the chemical wastewater pretreatment unit, and the hydrogen peroxide wastewater inlet is connected to the hydrogen peroxide wastewater pretreatment outlet of the hydrogen peroxide wastewater pretreatment unit.

[0009] Optionally, the hydrogen peroxide wastewater pretreatment unit includes a homogenized oil separator and an air flotation oil removal tank connected together. The homogenized oil separator includes an inlet and an outlet, wherein the inlet is used to introduce hydrogen peroxide wastewater. The air flotation oil removal tank includes an air flotation oil removal inlet and an air flotation oil removal outlet. The air flotation oil removal inlet is connected to the outlet of the homogenized oil separator, and the air flotation oil removal outlet forms the hydrogen peroxide wastewater pretreatment outlet of the hydrogen peroxide wastewater pretreatment unit.

[0010] Optionally, the air flotation oil removal tank further includes an air flotation oil removal cross-line inlet for directly introducing hydrogen peroxide wastewater into the air flotation oil removal tank; The bottom of the homogenized oil separator is also provided with a first sludge discharge port; the upper part of the air flotation oil removal tank is also provided with a second sludge discharge port.

[0011] Optionally, the chemical wastewater pretreatment unit includes a homogenizing tank; The homogenizing tank includes a homogenizing tank inlet and a homogenizing tank outlet. The homogenizing tank inlet is used to introduce chemical wastewater. The homogenizing tank outlet forms the chemical wastewater pretreatment outlet of the chemical wastewater pretreatment unit.

[0012] Optionally, the catalytic reaction unit includes a connected acidification tank and a catalytic reaction vessel; The acidification tank includes a first wastewater inlet, a second wastewater inlet, and an acidified wastewater outlet; the first wastewater inlet is connected to the homogenization tank outlet, and the second wastewater inlet is connected to the flotation oil removal outlet of the flotation oil removal tank; and / or, the flotation oil removal outlet is connected to the connecting pipeline between the homogenization tank outlet and the first wastewater inlet; The catalytic reaction tank includes a catalytic reaction tank inlet and a catalytic reaction tank outlet; the catalytic reaction tank inlet is connected to the acidified wastewater outlet of the acidification tank.

[0013] Optionally, the acidification tank further includes an acid dosing port, a catalyst dosing port, a first pH detection device, an acid dosing device, and a first stirring device; The probe of the first pH detection device is located inside the acidification tank to detect the pH value of the liquid inside; the acid dosing device is signal-connected to the first pH detection device and is used to add acid into the acidification tank through the acid dosing port according to the pH value detected by the first pH detection device. The first stirring device is located inside the acidification tank.

[0014] Optionally, the catalytic reaction vessel further includes a hydrogen peroxide dosing inlet, a first dosing device, and a stirring device; The hydrogen peroxide dosing inlet is connected to the hydrogen peroxide storage tank; The first dosing device is used to add oxidant to the catalytic reaction tank according to the amount of hydrogen peroxide wastewater. The stirring device is located inside the catalytic reaction vessel.

[0015] Optionally, the acid-base neutralization and precipitation unit includes an acid-base neutralization and precipitation tank, which includes an inlet and an outlet. The inlet is connected to the outlet of the catalytic reaction tank. The outlet is connected to a subsequent treatment device.

[0016] Optionally, the acid-base neutralization sedimentation tank further includes an alkali dosing inlet and a coagulant dosing inlet; The acid-base neutralization and precipitation unit also includes an alkaline solution storage tank, a coagulant storage tank, a second pH detection device, and a second dosing device. The probe of the second pH detection device is installed inside the acid-base neutralization sedimentation tank to detect the pH value of the liquid inside the acid-base neutralization sedimentation tank; the second dosing device is signal-connected to the second pH detection device to add alkali into the acid-base neutralization sedimentation tank through the alkali dosing inlet according to the pH value detected by the second pH detection device. The coagulant dosing inlet is connected to the coagulant storage tank.

[0017] Optionally, the acid-base neutralization sedimentation tank includes a stirring neutralization zone and a settling zone; the acid-base neutralization sedimentation tank also includes a third sludge discharge outlet; the third sludge discharge outlet is located at the bottom of the acid-base neutralization sedimentation tank; The top of the settling zone is also provided with an overflow weir, which serves as the outlet of the acid-base neutralization sedimentation tank.

[0018] Through the above technical solution, this disclosure provides a combined treatment system for chemical wastewater and hydrogen peroxide wastewater. The chemical wastewater and hydrogen peroxide wastewater are mixed, and the peroxides in the hydrogen peroxide wastewater undergo catalytic oxidation under acidic catalytic conditions. This not only eliminates organic matter in the chemical wastewater and improves its biodegradability, but also significantly reduces the concentration of peroxides in the hydrogen peroxide wastewater, achieving the goal of "treating waste with waste". The wastewater obtained after the combined treatment meets the requirements for entering the sewage treatment plant, which has good economic benefits and significantly reduces the cost of sewage treatment plants.

[0019] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings: Figure 1 This is an exemplary schematic diagram of a combined treatment system for chemical wastewater and hydrogen peroxide wastewater provided in this disclosure.

[0021] Explanation of reference numerals in the attached figures 1-Catalytic reaction tank, 2-Acid-base neutralization precipitation tank, 3-Homogenizing tank, 4-Acidification tank, 5-Acid storage tank, 6-Catalyst storage tank, 7-Homogenizing oil separator, 8-Air flotation oil removal tank, 9-Hydrogen peroxide storage tank, 10-Alkali storage tank, 11-Coagulant storage tank; G1 - Hydrogen peroxide wastewater, J1 - Homogenizing oil separator inlet, C1 - Homogenizing oil separator outlet, P1 - First sludge discharge outlet, J2 - Air flotation oil removal inlet, C2 - Air flotation oil removal outlet, J7 - Air flotation oil removal cross-line inlet, P2 - Second sludge discharge outlet, J7 - Air flotation oil removal cross-line inlet, G2 - Chemical wastewater, J3 - Homogenizing tank inlet, C3 - Homogenizing tank outlet, J4 - First wastewater inlet, C4 - Acidified wastewater outlet, J5 - Catalytic reactor inlet, C5 - Catalytic reactor outlet, J6 - Second wastewater inlet, J8 - Acid-base neutralization sedimentation tank inlet, C6 - Acid-base neutralization sedimentation tank outlet, P3 - Third sludge discharge outlet, Y1 - Acid dosing inlet, Y2 - Catalyst dosing inlet, Y3 - Hydrogen peroxide dosing inlet, Y4 - Alkali dosing inlet, Y5 - Coagulant dosing inlet. Detailed Implementation

[0022] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0023] This disclosure provides a combined treatment system for chemical wastewater and hydrogen peroxide wastewater. The system includes a chemical wastewater pretreatment unit, a hydrogen peroxide wastewater pretreatment unit, and a catalytic reaction unit and an acid-base neutralization precipitation unit connected in sequence. The catalytic reaction unit includes a chemical wastewater inlet and a hydrogen peroxide wastewater inlet; the chemical wastewater inlet is connected to the chemical wastewater pretreatment outlet of the chemical wastewater pretreatment unit, and the hydrogen peroxide wastewater inlet is connected to the hydrogen peroxide wastewater pretreatment outlet of the hydrogen peroxide wastewater pretreatment unit.

[0024] This disclosure provides a combined treatment system for chemical wastewater and hydrogen peroxide wastewater. The chemical wastewater and hydrogen peroxide wastewater are mixed, and the peroxides in the hydrogen peroxide wastewater undergo catalytic oxidation under acidic catalytic conditions. This not only eliminates organic matter in the chemical wastewater and improves its biodegradability, but also significantly reduces the concentration of peroxides in the hydrogen peroxide wastewater, achieving the goal of "treating waste with waste". The wastewater obtained after the combined treatment meets the requirements for entering a sewage treatment plant, which has good economic benefits and significantly reduces the cost of sewage treatment plants.

[0025] In one specific embodiment, the mass ratio of chemical wastewater introduced into the chemical wastewater pretreatment unit to hydrogen peroxide wastewater introduced into the hydrogen peroxide wastewater pretreatment unit is 0.1~10:1; preferably 0.1~0.5:1. The chemical wastewater has a pH of 2~10, COD of 1000~20000 mg / L, BOD of 100~1000 mg / L, and BOD / COD of 0.01~0.12; the hydrogen peroxide wastewater has a pH of 3~5, COD of 500~2000 mg / L, BOD of 0~25 mg / L, and BOD / COD of 0~0.05.

[0026] In one implementation, such as Figure 1 As shown, the hydrogen peroxide wastewater pretreatment unit includes a homogenized oil separator 7 and an air flotation oil removal tank 8 connected to each other. The homogenized oil separator 7 includes a homogenized oil separator inlet J1 and a homogenized oil separator outlet C1. The homogenized oil separator inlet J1 is used to introduce hydrogen peroxide wastewater G1. The flotation tank includes an oil flotation inlet J2 and an oil flotation outlet C2. The oil flotation inlet J2 is connected to the outlet C1 of the homogenized oil separator. The oil flotation outlet C2 forms the hydrogen peroxide wastewater pretreatment outlet of the hydrogen peroxide wastewater pretreatment unit.

[0027] In one implementation, such as Figure 1 As shown, the air flotation oil removal tank 8 also includes an air flotation oil removal cross-line inlet J7, used to directly introduce hydrogen peroxide wastewater G1 into the air flotation oil removal tank 8. Specifically, when the oil content of the hydrogen peroxide wastewater is less than 100 mg / L, the hydrogen peroxide wastewater G1 can be directly introduced into the air flotation oil removal tank to ensure stable system operation.

[0028] In one implementation, such as Figure 1 As shown, the bottom of the homogenized oil separator 7 is also provided with a first sludge discharge port P1; the upper part of the air flotation oil removal tank 8 is also provided with a second sludge discharge port P2.

[0029] According to this disclosure, such as Figure 1 As shown, hydrogen peroxide wastewater G1 enters the homogenizing oil separator tank through the inlet J1 for water quality adjustment, and then enters the air flotation oil removal device for treatment through the outlet C1 of the homogenizing oil separator tank and the inlet J2 of the air flotation oil removal device. The treated hydrogen peroxide wastewater flows out of the hydrogen peroxide wastewater pretreatment unit through the air flotation oil removal outlet C2. Furthermore, the impurities deposited in the homogenizing oil separator tank can be discharged through the first sludge discharge port P1. In the air flotation oil removal device, since the air flotation oil removal device is used, the impurities (such as sludge) generated by air flotation are lighter than water and can be discharged through the upper second sludge discharge port P2.

[0030] In one embodiment, the hydrogen peroxide wastewater is kept in a homogenized oil separator for 12 to 72 hours, preferably 24 hours.

[0031] In one specific embodiment, the air flotation oil removal tank 8 is selected from one or more of the vortex air flotation device and the dissolved air flotation device, preferably the dissolved air flotation device.

[0032] In one specific embodiment, the homogenized oil separator 7 and the air flotation oil removal tank 8 each independently include an oil removal auxiliary device; the oil removal auxiliary device includes one or more of an air compressor, a booster pump, and an oil skimmer.

[0033] In this disclosure, each device can be a device with a conventional structure in the art.

[0034] In one implementation, such as Figure 1 As shown, the chemical wastewater pretreatment unit includes a homogenizing tank 3; The homogenizing tank 3 includes a homogenizing tank inlet J3 and a homogenizing tank outlet C3. The homogenizing tank inlet J3 is used to introduce chemical wastewater G2; the homogenizing tank outlet C3 forms the chemical wastewater pretreatment outlet of the chemical wastewater pretreatment unit. In this disclosure, chemical wastewater G2 is introduced into the homogenizing tank 3 via the homogenizing tank inlet J3 for water quality adjustment.

[0035] In one specific embodiment, the residence time of the chemical wastewater in the homogenizing tank 3 is 12 to 72 hours, preferably 24 hours.

[0036] In one implementation, such as Figure 1 As shown, the catalytic reaction unit includes an acidification tank 4 and a catalytic reaction vessel 1 connected to each other; The acidification tank 4 includes a first wastewater inlet J4, a second wastewater inlet J6, and an acidified wastewater outlet C4; the first wastewater inlet J4 is connected to the homogenization tank outlet C3 of the homogenization tank 3, and the second wastewater inlet J6 is connected to the air flotation oil removal outlet C2 of the air flotation oil removal tank 8; and / or, the air flotation oil removal outlet C2 is connected to the connecting pipeline between the homogenization tank outlet C3 and the first wastewater inlet J4; The catalytic reactor 1 includes a catalytic reactor inlet J5 and a catalytic reactor outlet C5; the catalytic reactor inlet J5 is connected to the acidified wastewater outlet C4 of the acidification tank 4. In this disclosure, hydrogen peroxide wastewater from the air flotation oil removal tank can be directly introduced into the acidification tank via the second wastewater inlet J6, and / or, the hydrogen peroxide wastewater from the air flotation oil removal tank can be introduced into the connecting pipeline between the homogenizer outlet C3 and the first wastewater inlet J4 to mix with the chemical wastewater from the homogenizer before being introduced into the acidification tank; the mixed wastewater after acidification in the acidification tank is then introduced into the catalytic reactor for treatment.

[0037] The catalysts and oxidants used in the catalytic reaction units of this disclosure can be reagents conventionally selected in the art; the catalytic reaction conditions can also be conventional reaction conditions in the art.

[0038] In one implementation, such as Figure 1 As shown, the acidification tank 4 also includes an acid dosing port Y1, a catalyst dosing port Y2, a first pH detection device, an acid dosing device, and a first stirring device; The probe of the first pH detection device is located inside the acidification tank 4 to detect the pH value of the liquid inside; the acid dosing device is signal-connected to the first pH detection device and is used to add acid into the acidification tank 4 through the acid dosing port Y1 according to the pH value detected by the first pH detection device, thereby controlling the pH in the acidification tank 4 to be 3.0~4.0. The first stirring device is located inside the acidification tank 4.

[0039] In one specific embodiment, the acid solution is selected from one or more of dilute sulfuric acid, hydrochloric acid, and phosphoric acid, preferably sulfuric acid.

[0040] In one implementation, such as Figure 1 As shown, the catalytic reaction tank 1 also includes a hydrogen peroxide dosing inlet Y3, a first dosing device, and a stirring device; The hydrogen peroxide dosing inlet Y3 is connected to the hydrogen peroxide storage tank 9; The first dosing device is used to add oxidant to the catalytic reaction tank 1 according to the amount of hydrogen peroxide wastewater; The stirring device is located inside the catalytic reaction tank 1.

[0041] In one specific embodiment, the stirring device is selected from one or more of hydraulic stirring devices, mechanical stirring devices, and air stirring devices.

[0042] In this disclosure, the catalyst added to the catalytic reactor includes ferrous salts, preferably a ferrous sulfate solution with a mass concentration of 20-30% by weight; the oxidant can be selected from one or more of hydrogen peroxide, hypochlorite, and persulfate, preferably hydrogen peroxide, and preferably, hydrogen peroxide from the introduced hydrogen peroxide wastewater can be used as the oxidant without the need for additional oxidant; the amount of oxidant added depends on the volume of hydrogen peroxide wastewater, preferably 0.25-2 times the remaining COD corresponding to the peroxide equivalent in the hydrogen peroxide wastewater, and the amount of catalyst added is 1-8 times the total amount of oxidant added; the reaction time is 0.5-4 hours, preferably 1 hour.

[0043] In one implementation, such as Figure 1 As shown, the acid-base neutralization and precipitation unit includes an acid-base neutralization and precipitation tank 2, which includes an acid-base neutralization and precipitation tank inlet J8 and an acid-base neutralization and precipitation tank outlet C6. The acid-base neutralization and precipitation tank inlet J8 is connected to the catalytic reaction tank outlet C5 of the catalytic reaction tank 1. The acid-base neutralization and precipitation tank outlet C6 is used to connect to the subsequent treatment device.

[0044] In one implementation, such as Figure 1 As shown, the acid-base neutralization sedimentation tank 2 also includes an alkali dosing inlet Y4 and a coagulant dosing inlet Y5; The acid-base neutralization and precipitation unit also includes an alkaline solution storage tank 10, a coagulant storage tank 11, a second pH detection device, and a second dosing device. The probe of the second pH detection device is installed inside the acid-base neutralization sedimentation tank 2 to detect the pH value of the liquid inside the acid-base neutralization sedimentation tank 2; the second dosing device is signal-connected to the second pH detection device to add alkali into the acid-base neutralization sedimentation tank 2 through the alkali dosing inlet Y4 to adjust the pH value to neutral according to the pH value detected by the second pH detection device. The coagulant dosing inlet Y5 is connected to the coagulant storage tank 11.

[0045] In one specific embodiment, the added alkali can be NaOH, or other alkalis conventional in the art.

[0046] In one embodiment, the acid-base neutralization sedimentation tank 2 includes a stirring neutralization zone and a settling zone; specifically, the effluent from the stirring neutralization zone automatically flows into the settling zone for further purification of the wastewater, which is beneficial for subsequent entry into the biochemical treatment device for wastewater treatment. In one embodiment, the acid-base neutralization sedimentation tank 2 further includes a third sludge discharge port P3; the third sludge discharge port P3 is located at the bottom of the acid-base neutralization sedimentation tank 2; In one embodiment, the top of the settling zone is further provided with an overflow weir, which forms the outlet C6 of the acid-base neutralization sedimentation tank.

[0047] According to this disclosure, such as Figure 1 As shown, wastewater from the catalytic reactor enters the alkali neutralization zone through the inlet J8 of the acid-base neutralization sedimentation tank. Coagulants and flocculants are added through the coagulant dosing inlet Y5 for sedimentation and purification. The resulting effluent flows into the sedimentation reaction zone for settling and then flows out through the wastewater outlet H11 to enter subsequent treatment devices, such as a biological treatment device. The sedimentation residue can be discharged through the third sludge outlet P3 at the bottom of the settling zone and can be dewatered for further treatment.

[0048] The coagulants and flocculants used in the sedimentation tank of this disclosure can be conventionally selected in the art, and the dosage can be adjusted according to the actual situation.

[0049] In one specific embodiment, a coagulant and a flocculant are added to the acid-base neutralization sedimentation tank; preferably, the coagulant is PAC, with a dosage of 50 mg / L to 200 mg / L, and the flocculant is PAM, with a dosage of 1 to 10 mg / L, wherein the dosage of the coagulant and the flocculant is calculated according to the amount of wastewater to be treated.

[0050] In one specific implementation, such as Figure 1 As shown, a combined treatment system for chemical wastewater and hydrogen peroxide wastewater is disclosed. The system includes a chemical wastewater pretreatment unit, a hydrogen peroxide wastewater pretreatment unit, and a catalytic reaction unit and an acid-base neutralization and precipitation unit connected sequentially. The catalytic reaction unit includes a chemical wastewater inlet and a hydrogen peroxide wastewater inlet. The chemical wastewater inlet is connected to the chemical wastewater pretreatment outlet of the chemical wastewater pretreatment unit, and the hydrogen peroxide wastewater inlet is connected to the hydrogen peroxide wastewater pretreatment outlet of the same unit. The hydrogen peroxide wastewater pretreatment unit includes a homogenized oil separator 7 and an air flotation oil removal tank 8 connected to each other. The homogenized oil separator 7 includes an inlet J1 and an outlet C1, with the inlet J1 used to introduce hydrogen peroxide wastewater G1. The air flotation tank includes an air flotation oil removal inlet J2 and an outlet C2, with the inlet J2 connected to the outlet C1, and the outlet C2 serving as the hydrogen peroxide wastewater pretreatment outlet of the unit. The air flotation oil removal tank 8 also includes an air flotation oil removal cross-line inlet J7 for directly introducing hydrogen peroxide wastewater G1 into the tank. The bottom of the homogenized oil separator 7 is also provided with a first sludge discharge port P1, and the upper part of the air flotation oil removal tank 8 is also provided with a second sludge discharge port P2. The chemical wastewater pretreatment unit includes a homogenizing tank 3; the homogenizing tank 3 includes a homogenizing tank inlet J3 and a homogenizing tank outlet C3, the homogenizing tank inlet J3 is used to introduce chemical wastewater G2; the homogenizing tank outlet C3 forms the chemical wastewater pretreatment outlet of the chemical wastewater pretreatment unit; The catalytic reaction unit includes an acidification tank 4 and a catalytic reaction vessel 1 connected together. The acidification tank 4 includes a first wastewater inlet J4, a second wastewater inlet J6, and an acidified wastewater outlet C4. The first wastewater inlet J4 is connected to the homogenization tank outlet C3 of the homogenization tank 3, and the second wastewater inlet J6 is connected to the flotation oil removal outlet C2 of the flotation oil removal tank 8. Alternatively, the flotation oil removal outlet C2 is connected to a connecting pipeline between the homogenization tank outlet C3 and the first wastewater inlet J4. The catalytic reaction vessel 1 includes a catalytic reaction vessel inlet J5 and a catalytic reaction vessel outlet C5. The catalytic reaction vessel inlet J5 is connected to the acidified wastewater outlet C4 of the acidification tank 4. The acidification tank 4 also includes an acid dosing port Y1 and a catalyst dosing port Y2. The catalytic reaction tank 1 includes a first pH detection device, an acid dosing device, and a first stirring device. The probe of the first pH detection device is located inside the acidification tank 4 to detect the pH value of the internal liquid. The acid dosing device is signal-connected to the first pH detection device and is used to add acid to the acidification tank 4 via the acid dosing port Y1 according to the pH value detected by the first pH detection device. The first stirring device is located inside the acidification tank 4. The catalytic reaction tank 1 also includes a hydrogen peroxide dosing inlet Y3, a first dosing device, and a second stirring device. The hydrogen peroxide dosing inlet Y3 is connected to a hydrogen peroxide storage tank 9. The first dosing device is used to add oxidant to the catalytic reaction tank 1 according to the amount of hydrogen peroxide wastewater. The stirring device is located inside the catalytic reaction tank 1. The acid-base neutralization and precipitation unit includes an acid-base neutralization and precipitation tank 2, which has an inlet J8 and an outlet C6. The inlet J8 is connected to the outlet C5 of the catalytic reaction tank 1. The outlet C6 is connected to a subsequent treatment device. The acid-base neutralization and precipitation tank 2 also includes an alkali dosing inlet Y4 and a coagulant dosing inlet Y5. The unit further includes an alkali storage tank 10, a coagulant storage tank 11, a second pH detection device, and a second dosing device. The probe of the second pH detection device is located inside the acid-base neutralization and precipitation tank 2. The second dosing device is used to detect the pH value of the liquid inside the acid-base neutralization sedimentation tank 2; the second dosing device is signal-connected to the second pH detection device, and is used to add alkali into the acid-base neutralization sedimentation tank 2 through the alkali dosing inlet Y4 according to the second pH value detected by the second pH detection device; the coagulant dosing inlet Y5 is connected to the coagulant storage tank 11; the acid-base neutralization sedimentation tank 2 includes a stirring neutralization zone and a static sedimentation zone; the acid-base neutralization sedimentation tank 2 also includes a third sludge discharge port P3; the third sludge discharge port P3 is located at the bottom of the acid-base neutralization sedimentation tank 2; the top of the static sedimentation zone is also provided with an overflow weir to form the outlet C6 of the acid-base neutralization sedimentation tank.

[0051] The specific process flow in each processing unit has been described in detail above and will not be repeated here.

[0052] The technical solution of this disclosure will be further explained below with reference to specific implementation methods.

[0053] Example 1 This embodiment is used to verify the effectiveness of catalytic oxidation reaction in the joint treatment of chemical wastewater and hydrogen peroxide wastewater.

[0054] Wastewater from the HPPO unit in the chemical workshop of a petrochemical refinery and its associated hydrogen peroxide were collected. The BOD of the chemical wastewater was only 0.05, while the BOD of the hydrogen peroxide wastewater was 0 due to the presence of high concentrations of peroxides. Therefore, the wastewater could not meet the requirements for centralized treatment at the sewage treatment plant. The specific water quality conditions are shown in Table 1.

[0055] Table 1

[0056] use Figure 1 The system shown was tested under different dosing conditions with chemical wastewater and hydrogen peroxide wastewater mixed at a volume ratio of 2:1 (the theoretical COD of the mixed wastewater was 7067.3 mg / L, and the measured COD was 6950.0 mg / L). The pH of the wastewater in the catalytic oxidation unit was controlled at 3, and the reaction time was 1 h. The experimental setup and results are shown in Table 2 below.

[0057] Table 2

[0058] As can be seen from the data in Table 2, by using the combined treatment system provided in this disclosure and conducting different dosing tests after mixing chemical wastewater and hydrogen peroxide wastewater, the biodegradability can be improved to a certain extent even without adding oxidants. Further increasing the dosage of ferrous sulfate and hydrogen peroxide within a certain range can significantly improve the biodegradability of the treated wastewater. Furthermore, a hydrogen peroxide dosage of less than 6000 mg / L can ensure that the wastewater treated by the combined treatment system has even better biodegradability.

[0059] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0060] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0061] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A combined treatment system for chemical wastewater and hydrogen peroxide wastewater, characterized in that, The system includes a chemical wastewater pretreatment unit, a hydrogen peroxide wastewater pretreatment unit, and a catalytic reaction unit and an acid-base neutralization precipitation unit connected in sequence. The catalytic reaction unit includes a chemical wastewater inlet and a hydrogen peroxide wastewater inlet; the chemical wastewater inlet is connected to the chemical wastewater pretreatment outlet of the chemical wastewater pretreatment unit, and the hydrogen peroxide wastewater inlet is connected to the hydrogen peroxide wastewater pretreatment outlet of the hydrogen peroxide wastewater pretreatment unit.

2. The system according to claim 1, characterized in that, The hydrogen peroxide wastewater pretreatment unit includes a homogenized oil separator (7) and an air flotation oil removal tank (8) connected to each other. The homogenized oil separator (7) includes a homogenized oil separator inlet (J1) and a homogenized oil separator outlet (C1), wherein the homogenized oil separator inlet (J1) is used to introduce hydrogen peroxide wastewater (G1). The air flotation oil removal tank (8) includes an air flotation oil removal inlet (J2) and an air flotation oil removal outlet (C2). The air flotation oil removal inlet (J2) is connected to the outlet (C1) of the homogenized oil separator. The air flotation oil removal outlet (C2) forms the hydrogen peroxide wastewater pretreatment outlet of the hydrogen peroxide wastewater pretreatment unit.

3. The system according to claim 2, characterized in that, The air flotation oil removal tank (8) also includes an air flotation oil removal cross-line inlet (J7) for directly introducing hydrogen peroxide wastewater (G1) into the air flotation oil removal tank (8). The bottom of the homogenized oil separator (7) is also provided with a first sludge discharge port (P1); the upper part of the air flotation oil removal tank (8) is also provided with a second sludge discharge port (P2).

4. The system according to claim 2, characterized in that, The chemical wastewater pretreatment unit includes a homogenizing tank (3); The homogenizing tank (3) includes a homogenizing tank inlet (J3) and a homogenizing tank outlet (C3). The homogenizing tank inlet (J3) is used to introduce chemical wastewater (G2). The homogenizing tank outlet (C3) forms the chemical wastewater pretreatment outlet of the chemical wastewater pretreatment unit.

5. The system according to claim 4, characterized in that, The catalytic reaction unit includes a connected acidification tank (4) and a catalytic reaction vessel (1). The acidification tank (4) includes a first wastewater inlet (J4), a second wastewater inlet (J6), and an acidified wastewater outlet (C4); the first wastewater inlet (J4) is connected to the homogenization tank outlet (C3) of the homogenization tank (3), and the second wastewater inlet (J6) is connected to the air flotation oil removal outlet (C2) of the air flotation oil removal tank (8); and / or, the air flotation oil removal outlet (C2) is connected to the connecting pipeline between the homogenization tank outlet (C3) and the first wastewater inlet (J4); The catalytic reaction tank (1) includes a catalytic reaction tank inlet (J5) and a catalytic reaction tank outlet (C5); the catalytic reaction tank inlet (J5) is connected to the acidified wastewater outlet (C4) of the acidification tank (4).

6. The system according to claim 5, characterized in that, The acidification tank (4) also includes an acid dosing port (Y1), a catalyst dosing port (Y2), a first pH detection device, an acid dosing device, and a first stirring device; The probe of the first pH detection device is located inside the acidification tank (4) to detect the pH value of the liquid inside; the acid dosing device is signal-connected to the first pH detection device to add acid into the acidification tank (4) through the acid dosing port (Y1) according to the pH value detected by the first pH detection device. The first stirring device is located inside the acidification tank (4).

7. The system according to claim 5, characterized in that, The catalytic reaction vessel (1) also includes a hydrogen peroxide dosing inlet (Y3), a first dosing device, and a stirring device; The hydrogen peroxide dosing inlet (Y3) is connected to the hydrogen peroxide storage tank (9); The first dosing device is used to add oxidant to the catalytic reaction tank (1) according to the amount of hydrogen peroxide wastewater; The stirring device is located inside the catalytic reaction vessel (1).

8. The system according to claim 5, characterized in that, The acid-base neutralization precipitation unit includes an acid-base neutralization precipitation tank (2), which includes an acid-base neutralization precipitation tank inlet (J8) and an acid-base neutralization precipitation tank outlet (C6). The acid-base neutralization precipitation tank inlet (J8) is connected to the catalytic reaction tank outlet (C5) of the catalytic reaction tank (1). The acid-base neutralization precipitation tank outlet (C6) is used to connect to the subsequent treatment device.

9. The system according to claim 8, characterized in that, The acid-base neutralization sedimentation tank (2) also includes an alkali dosing inlet (Y4) and a coagulant dosing inlet (Y5); The acid-base neutralization and precipitation unit also includes an alkaline solution storage tank (10), a coagulant storage tank (11), a second pH detection device, and a second dosing device; The probe of the second pH detection device is installed inside the acid-base neutralization sedimentation tank (2) to detect the pH value of the liquid inside the acid-base neutralization sedimentation tank (2); the second dosing device is signal-connected to the second pH detection device to add alkali into the acid-base neutralization sedimentation tank (2) through the alkali dosing inlet (Y4) according to the pH value detected by the second pH detection device. The coagulant dosing inlet (Y5) is connected to the coagulant storage tank (11).

10. The system according to claim 9, characterized in that, The acid-base neutralization sedimentation tank (2) includes a stirring neutralization zone and a settling zone; the acid-base neutralization sedimentation tank (2) also includes a third sludge discharge port (P3); the third sludge discharge port (P3) is located at the bottom of the acid-base neutralization sedimentation tank (2); The top of the settling zone is also provided with an overflow weir, which forms the outlet of the acid-base neutralization sedimentation tank (C6).

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