Integrated continuous flow Fenton reaction device

Abstract

The utility model discloses an integrated continuous flow Fenton reaction device. Comprising a first pH adjusting tank, a reaction tank, a second pH adjusting tank, a flocculation tank and a sedimentation tank which are sequentially communicated and are of an integrated structure; the right upper part of the first pH regulating tank is connected to the reaction tank through an overflow port; the bottom of the reaction tank is connected to a second pH regulating tank through a pipeline; a water outlet in the upper part of the second pH regulating tank is connected to the flocculation tank; the top and the bottom of the flocculation basin are connected to the sedimentation basin through a pipeline; a sludge discharge port and a clear water discharge port are formed in the bottom of the sedimentation tank, and clear water at the upper part is discharged through an overflow weir; drain valves are arranged at the bottoms of the first pH regulating tank and the reaction tank and are used for emptying residual liquid during cleaning. According to the utility model, efficient cooperation of Fenton reaction and flocculation precipitation is realized through a multi-stage continuous flow design, and the problem of low efficiency of traditional intermittent treatment is solved.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment technology, specifically to a continuous flow reaction device based on the Fenton oxidation method, which is particularly suitable for the efficient degradation of high-concentration organic wastewater (such as dyeing and pharmaceutical wastewater). Background Technology

[0002] With industrial development, the treatment of high-concentration organic wastewater (such as dyeing, pharmaceutical, and chemical wastewater) has become a challenge in the environmental protection field. This type of wastewater has high chemical oxygen demand (COD), complex composition, and poor biodegradability, making it difficult for traditional biological treatment methods to effectively degrade it. The Fenton oxidation process, as a highly efficient advanced oxidation technology, utilizes Fe... 2+ It reacts with H2O2 to generate strong oxidizing hydroxyl radicals (·OH), which can decompose organic matter non-selectively and are widely used in the pretreatment or advanced treatment of high COD wastewater.

[0003] However, traditional Fenton reaction processes mostly employ batch operation, which has the following problems: 1. Low treatment efficiency: Batch reactions require frequent pH adjustment, chemical dosing, and settling, resulting in a cumbersome process, long hydraulic retention time, and difficulty in achieving continuous treatment; 2. Low reagent utilization: In an acidic environment (pH≈3), Fe... 2+ Easily oxidized to Fe 3+ 1. Catalyst deactivation, requiring excessive reagent addition and increasing operating costs; 2. Inaccurate reaction condition control: If pH adjustment and reagent addition are not matched in real time, it is easy to cause incomplete reaction and large fluctuations in COD removal rate (usually 50%-70%); 3. Secondary pollution of sludge: The iron sludge generated after the reaction needs to be treated separately. Traditional devices lack sludge separation optimization design and are prone to clogging pipelines; 4. Low equipment integration: Most of them adopt decentralized reaction tanks and sedimentation tanks, which occupy a large area and are difficult to adapt to small and medium-sized wastewater treatment scenarios.

[0004] In the prior art, an improved Fenton reactor is disclosed, which improves mass transfer efficiency through multi-stage aeration, but it is still an intermittent design and does not solve the problem of pH adjustment and flocculation synergy; a continuous flow Fenton device is proposed, but it does not integrate neutralization and precipitation units, and requires external equipment to complete the subsequent treatment, which complicates the process.

[0005] Therefore, there is an urgent need to develop a highly efficient, integrated, and continuously operating Fenton reactor to achieve efficient and stable treatment of high-COD wastewater through precise control of pH, reagent dosing, and sludge separation. Utility Model Content

[0006] To address the aforementioned technical shortcomings, an integrated continuous flow Fenton reactor was proposed. Through multi-unit integration, precise dosing, and automatic control, the COD removal rate and operational stability were significantly improved.

[0007] To achieve the above objectives, the integrated continuous flow Fenton reactor of this invention comprises a first pH adjustment tank (1), a reaction tank (2), a second pH adjustment tank (3), a flocculation tank (4), and a sedimentation tank (5) connected in sequence, with each tank having an integrated structure; wherein,

[0008] The first pH adjustment tank (1) has an inlet (6) on the lower left, a pH adjustment port (7) and a first stirrer (8) on the top, and is connected to the reaction tank (2) through an overflow port on the upper right.

[0009] The top of the reaction tank (2) is equipped with a hydrogen peroxide dosing port (9), a ferrous sulfate dosing port (10) and a second stirrer (11), and the bottom is connected to the second pH adjustment tank (3) through a pipeline;

[0010] The second pH adjustment tank (3) is equipped with a sodium hydroxide dosing port (12) and a third stirrer (13) at the top, and the upper outlet is connected to the flocculation tank (4);

[0011] The flocculation tank (4) is equipped with a PAC dosing port (14), a PAM dosing port (15) and a fourth agitator (16) at the top, and is connected to the sedimentation tank (5) at the bottom through a pipeline;

[0012] The sedimentation tank (5) is provided with a sludge discharge outlet and a clear water discharge outlet (17) at the bottom, and the clear water in the upper part is discharged through the overflow weir;

[0013] Both the first pH adjustment tank (1) and the reaction tank (2) are equipped with drain valves (18) at the bottom for draining residual liquid during cleaning.

[0014] Furthermore, the agitator is either a paddle or a turbine type, with a speed range of 50-300 rpm.

[0015] Furthermore, the pH adjustment port (7), hydrogen peroxide dosing port (9), ferrous sulfate dosing port (10), sodium hydroxide dosing port (12), PAC dosing port (14), and PAM dosing port (15) are all connected to the reagent storage tank via peristaltic pumps to achieve quantitative dosing.

[0016] Furthermore, the sludge discharge port and the clean water discharge port (17) at the bottom of the sedimentation tank (5) are controlled by a solenoid valve in a time-sharing manner.

[0017] Furthermore, the overall dimensions of the device are 1500mm long × 300mm wide × 700mm high, with an effective volume ≥ 60L and a hydraulic retention time of 1-4 hours.

[0018] To achieve the above objectives, the present invention provides a wastewater treatment method based on the aforementioned device, comprising the following steps:

[0019] S1) Wastewater enters the first pH adjustment tank (1) through the inlet (6), and the pH is adjusted to 2.5-3.5 by dilute sulfuric acid and then stirred and mixed.

[0020] S2) Wastewater enters reaction tank (2), and reacts with H2O2 and Fe... 2+ Add the reagent at a molar ratio of 5:1 to 10:1 and stir for 30 to 60 minutes.

[0021] After the S3 reaction, the wastewater enters the second pH adjustment tank (3), where the pH is adjusted to 6.5-7.5 with sodium hydroxide and then stirred and neutralized.

[0022] After neutralization, the wastewater enters the flocculation tank (4) and is flocculated at a dosage of 50-200 mg / L of PAC and 1-5 mg / L of PAM. The mixture is stirred slowly for 10-30 minutes.

[0023] S5) After flocculation, the wastewater enters the sedimentation tank (5). After settling for 1-2 hours, the sludge is discharged first and then the clean water is discharged. The COD removal rate is ≥80%.

[0024] This utility model has the following advantages:

[0025] (1) Integrated design

[0026] This device integrates traditionally separate pH adjustment tanks, reaction tanks, flocculation tanks, and sedimentation tanks into a single continuous flow unit. Connected via overflow outlets and pipelines, it reduces the need for connecting pipes and pumping equipment, thereby lowering energy consumption and the risk of failure. With dimensions of only 1500mm × 300mm × 700mm (effective volume ≥ 60L), it is suitable for miniaturized, modular deployment, particularly ideal for laboratory or small-to-medium-scale wastewater treatment scenarios.

[0027] (2) Precision control and automation

[0028] Chemical dosing system: All dosing ports (pH adjustment, H2O2, Fe) 2+ Both PAC and PAM are quantitatively added via peristaltic pumps to achieve dynamic matching of agent dosage and wastewater flow rate, avoiding over-dosing or insufficient reaction.

[0029] Time-sharing sludge / water discharge control: The sludge discharge outlet and the clean water discharge outlet of the sedimentation tank are controlled by electromagnetic valves in a time-sharing manner to ensure that the sludge is emptied before the clean water is discharged, thereby reducing the carrying of suspended solids.

[0030] (3) Optimization of efficient reaction conditions

[0031] pH segmented control: pH adjustment tank I first adjusts the influent pH to 2.5-3.5 (the optimal acidic environment for the Fenton reaction); pH adjustment tank II then neutralizes it to 6.5-7.5 (suitable conditions for flocculation and sedimentation) to avoid secondary dissolution of iron sludge.

[0032] Enhanced mixing: Each tank uses a paddle or turbine agitator (50-300 rpm) to ensure full contact between the reagent and the wastewater, and to promote the reaction of H2O2 and Fe in the reaction tank. 2+ The molar ratio is strictly controlled between 5:1 and 10:1 to improve the efficiency of hydroxyl radical (·OH) generation.

[0033] (4) Scalability and ease of maintenance

[0034] Both the pH adjustment tank I and the bottom of the reaction tank are equipped with drain valves to facilitate the rapid drainage of residual liquid during cleaning, preventing reagent deposition or equipment corrosion. This device can be used as a standalone unit or integrated into other treatment systems (such as the process chain of the integrated wastewater treatment system in the laboratory building) to replace traditional Fenton reactors and improve overall efficiency. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the integrated continuous flow Fenton reactor of this utility model.

[0036] Figure 2 This is a planar schematic diagram.

[0037] Drawing number explanation:

[0038] First pH adjustment tank (1), reaction tank (2), second pH adjustment tank (3), flocculation tank (4), sedimentation tank (5), inlet (6), pH adjustment port (7), first agitator (8), hydrogen peroxide dosing port (9), ferrous sulfate dosing port (10), second agitator (11), sodium hydroxide dosing port (12), third agitator (13), PAC dosing port (14), PAM dosing port (15), fourth agitator (16), sludge discharge port and clear water discharge port (17), drain valve (19) Detailed Implementation

[0039] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0040] In the description of this utility model, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0041] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0042] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0043] As shown in the figure, this utility model provides an integrated continuous flow Fenton reactor and processing method, the core of which includes:

[0044] 1. Integrated continuous flow device: It consists of a first pH adjustment tank, a reaction tank, a second pH adjustment tank, a flocculation tank and a sedimentation tank connected in sequence. It adopts a compact design (1500mm long × 300mm wide × 700mm high, effective volume ≥ 60L). Each unit achieves gravity flow of sewage through overflow outlets and pipelines, and the hydraulic retention time is 1-4 hours.

[0045] 2. Precise Control and Synergistic Treatment: pH is adjusted in stages using dilute sulfuric acid (first pH adjustment tank) and sodium hydroxide (second pH adjustment tank) to control the reaction environment (pH 2.5-3.5→6.5-7.5), ensuring efficient Fenton reaction and subsequent neutralization stability; quantitative addition of reagents is achieved using peristaltic pumps to precisely add H2O2, FeSO4 (molar ratio 5:1-10:1), PAC (50-200mg / L), and PAM (1-5mg / L), with each tank equipped with paddle / turbine agitators (50-300rpm) to enhance mixing; efficient sedimentation is achieved by using solenoid valves in the sedimentation tank to control sludge discharge and clear water overflow in a timed manner, improving sludge-water separation efficiency.

[0046] 3. Continuous treatment method: Wastewater undergoes acid conditioning, Fenton oxidation, neutralization, flocculation and sedimentation in sequence to achieve continuous operation of "influent-reaction-discharge", with a COD removal rate of ≥80%.

[0047] Example 1: Treatment of dyeing and printing wastewater. The wastewater from a dyeing and printing factory has an initial COD concentration of about 2000 mg / L, contains nitrogen dyes, surfactants and other recalcitrant organic matter, pH 8-9, and dark color.

[0048] 1. First pH Adjustment Tank:

[0049] - Wastewater at 1.5m 3 A flow rate of / h enters the device, and dilute sulfuric acid (concentration 10%) is added via a peristaltic pump to adjust the pH to 3.0±0.2;

[0050] - First, the mixer speed is 150 rpm, and the mixing time is 15 minutes.

[0051] 2. Fenton reaction tank:

[0052] -According to H2O2 and Fe 2+ Add reagents at a molar ratio of 8:1:

[0053] - Hydrogen peroxide (30%) dosage: 40 mL / min;

[0054] - Ferrous sulfate (FeSO4·7H2O) solution (10%) dosage: 25 mL / min;

[0055] - The second stirrer rotates at 200 rpm, the reaction time is 50 minutes, and the dissolved oxygen is controlled at ≥2 mg / L.

[0056] 3. Second pH adjustment tank:

[0057] - Add sodium hydroxide (10% solution) to adjust the pH to 7.0 ± 0.3 to neutralize the Fe produced in the reaction. 3+ ;

[0058] - The third mixer operates at 100 rpm for 10 minutes.

[0059] 4. Flocculation tank:

[0060] - Add 120 mg / L of PAC (polyaluminum chloride) and 3 mg / L of PAM (anionic, 0.1%);

[0061] - The fourth mixer runs at 30 rpm, and slow flocculation lasts for 20 minutes.

[0062] 5. Sedimentation tank:

[0063] - Let it stand and settle for 1.5 hours. The bottom sludge (95% moisture content) is discharged through a solenoid valve at regular intervals, and the clean water is discharged afterward.

[0064] Treatment results: The effluent COD is 320 mg / L, with a removal rate of ≥84%; the color is reduced from 500 times to less than 20 times; the sludge production rate is reduced by 25% compared with the traditional intermittent process, and the treatment cycle is shortened to 3.5 hours.

[0065] Example 2: A certain antibiotic pharmaceutical wastewater, COD 3500mg / L, contains residual antibiotics and fermentation byproducts, pH fluctuates greatly (5-10), and has high biotoxicity.

[0066] 1. First pH Adjustment Tank:

[0067] - Wastewater flow rate 1.2m 3 / h, add dilute sulfuric acid (20%) to adjust the pH to 2.8±0.2;

[0068] - First, mix at 180 rpm for 20 minutes.

[0069] 2. Fenton reaction tank:

[0070] -Uses a high oxidation strength ratio (H2O2:Fe) 2+ =10:1):

[0071] - Hydrogen peroxide (30%) dosage: 55 mL / min;

[0072] - Ferrous sulfate solution (15%) dosage: 30 mL / min;

[0073] - The second stirrer rotates at 250 rpm, the reaction time is 60 minutes, and the temperature is controlled at 25-30℃.

[0074] 3. Second pH adjustment tank:

[0075] - Add calcium hydroxide (5% suspension) to adjust the pH to 7.5±0.3, simultaneously removing residual Fe. 3+ ;

[0076] - The third mixer runs at 120 rpm for 15 minutes.

[0077] 4. Flocculation tank:

[0078] - Add PAC 180mg / L and PAM (non-ionic, 0.2%) 4mg / L;

[0079] - The fourth stirrer operates at 20 rpm, and the flocculation time is 25 minutes.

[0080] 5. Sedimentation tank:

[0081] After settling for 2 hours, the sludge (93% moisture content) is discharged in two stages through a solenoid valve (first discharge the thick sludge, then discharge the thin sludge), and the COD of the clean water is ≤500mg / L.

[0082] Treatment results: The COD of the effluent is 480 mg / L, with a removal rate of ≥86%; antibiotic residues are reduced from 85 mg / L to below the detection limit (<0.1 mg / L); the device occupies only 1.5m×0.3m×0.7m, making it suitable for plant space-constrained scenarios.

[0083] The present invention has been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above-described embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Many other changes and modifications made without departing from the concept and scope of the present invention should be considered within the protection scope of the present invention.

[0084] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0085] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. An integrated continuous flow Fenton reactor, characterized in that, It includes a first pH adjustment tank (1), a reaction tank (2), a second pH adjustment tank (3), a flocculation tank (4), and a sedimentation tank (5) connected in sequence, with each tank forming an integrated structure; among them, The first pH adjustment tank (1) has an inlet (6) on the lower left, a pH adjustment port (7) and a first stirrer (8) on the top, and is connected to the reaction tank (2) through an overflow port on the upper right. The top of the reaction tank (2) is equipped with a hydrogen peroxide dosing port (9), a ferrous sulfate dosing port (10) and a second stirrer (11), and the bottom is connected to the second pH adjustment tank (3) through a pipeline; The second pH adjustment tank (3) is equipped with a sodium hydroxide dosing port (12) and a third stirrer (13) at the top, and the upper outlet is connected to the flocculation tank (4); The flocculation tank (4) is equipped with a PAC dosing port (14), a PAM dosing port (15) and a fourth agitator (16) at the top, and is connected to the sedimentation tank (5) at the bottom through a pipeline; The sedimentation tank (5) is provided with a sludge discharge outlet and a clear water discharge outlet (17) at the bottom, and the clear water in the upper part is discharged through the overflow weir; Both the first pH adjustment tank (1) and the reaction tank (2) are equipped with drain valves (18) at the bottom for draining residual liquid during cleaning.

2. The integrated continuous flow Fenton reactor according to claim 1, characterized in that, The agitator is either paddle or turbine type, with a speed range of 50-300 rpm.

3. The integrated continuous flow Fenton reactor according to claim 1, characterized in that, The pH adjustment port (7), hydrogen peroxide dosing port (9), ferrous sulfate dosing port (10), sodium hydroxide dosing port (12), PAC dosing port (14), and PAM dosing port (15) are all connected to the reagent storage tank via peristaltic pumps to achieve quantitative dosing.

4. The integrated continuous flow Fenton reactor according to claim 1, characterized in that, The sludge discharge port and the clean water discharge port (17) at the bottom of the sedimentation tank (5) are controlled by a solenoid valve in a time-sharing manner.

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