Waste water treatment system in waste tire recycling

Abstract

The application relates to the technical field of water treatment equipment, in particular to a wastewater treatment system in waste tire recycling, which comprises an oil separation tank, an air flotation tank connected with the oil separation tank, a clarifier connected with the air flotation tank, a membrane bioreactor connected with the clarifier and a reverse osmosis unit connected with the membrane bioreactor. The wastewater treatment system in waste tire recycling provided by the application provides a complete wastewater treatment process for waste tire recycling pyrolysis, can effectively remove various impurities and pollutants in the wastewater, has a simple structure, is easy to layout, has a small land occupation, has a low construction cost and operation cost of the whole system, has high economy, is suitable for a wide range of applications and has high practicability.

Description

Technical Field

[0001] This application relates to the field of water treatment equipment technology, and in particular to a wastewater treatment system for waste tire recycling. Background Technology

[0002] Improper disposal of waste tires can cause serious environmental damage and resource waste. Tires left in the open for extended periods can release harmful substances that pollute soil and groundwater, and the heavy metals they contain may harm human health through the food chain. Statistics show that it takes over a century for a waste tire to naturally decompose, and more than 1 billion waste tires are generated globally each year. Improper disposal will create a huge environmental burden. Waste tire recycling and processing has significant environmental, economic, and resource implications. Through scientific recycling and processing, waste tires can be transformed into high-value resources such as recycled rubber, pyrolysis oil, carbon black, and steel wire, achieving the goal of "turning waste into treasure."

[0003] Waste tires are mainly composed of rubber, carbon black, steel wire, and various additives (such as vulcanizing agents, accelerators, and antioxidants). During dismantling, these components enter the wastewater in different forms. For example, the organic polymers in the rubber may undergo partial hydrolysis or degradation during dismantling and subsequent treatment, producing various small-molecule organic compounds; the chemical substances in the additives may also dissolve or disperse into the wastewater, making the wastewater composition extremely complex.

[0004] The sources and characteristics of wastewater are mainly reflected in the following aspects: The main sources are as follows: Cleaning wastewater: Before dismantling, the surface of the waste tires needs to be cleaned to remove mud, oil, and debris. This process generates a large amount of cleaning wastewater containing pollutants. Wastewater containing oil and detergent residue is also generated during equipment cleaning.

[0005] Cooling wastewater: Circulating water used to control temperature during the pyrolysis process, which may contain trace amounts of pyrolysis products or pollutants.

[0006] Wastewater from tail gas treatment: Wastewater containing pollutants may be generated during the purification process of tail gas produced by pyrolysis. For example, processes such as wet desulfurization will produce wastewater containing sulfur compounds.

[0007] Emergency wastewater: High-concentration organic wastewater generated by sudden malfunctions or accidents.

[0008] Pollutant characteristics High organic content: The wastewater may contain incompletely decomposed organic matter such as rubber and plastics, as well as fuel oil components, resulting in high chemical oxygen demand (COD) and biochemical oxygen demand (BOD).

[0009] High suspended solids content: Cooling wastewater and floor washing wastewater may contain suspended solids such as carbon black and soil, with high concentrations.

[0010] It may contain harmful substances such as sulfur compounds and heavy metal ions. The wastewater from the exhaust gas treatment may contain sulfur compounds derived from the conversion of sulfur oxides and nitrogen oxides; waste tires may contain small amounts of heavy metals, which may enter the wastewater during the pyrolysis process.

[0011] Large fluctuations in water quality: Due to the unstable source and composition of waste tires, as well as the intermittent nature of the production process, the amount of wastewater generated and the quality of the water will fluctuate significantly.

[0012] Therefore, wastewater treatment in waste tire recycling pyrolysis is a crucial step in ensuring its environmental protection and resource recycling. However, existing wastewater treatment processes for waste tire recycling pyrolysis often employ separate treatment methods for each stage, such as separate carbon black treatment processes and separate organic matter treatment processes. Each wastewater treatment stage operates independently, resulting in a very cumbersome overall wastewater treatment process.

[0013] Furthermore, existing wastewater treatment processes for waste tire recycling pyrolysis mostly employ Fenton oxidation combined with activated carbon adsorption. This method has the following drawbacks: Fenton oxidation primarily utilizes hydrogen peroxide and ferrous salts for treatment. Hydrogen peroxide is costly, produces a large amount of sludge, and has a narrow pH range (optimal pH = 2.5–3.5), requiring prior pH adjustment with acid (e.g., ...). After the reaction, the pH needs to be adjusted back to neutral using an alkali (such as NaOH), increasing reagent consumption; when pH > 4, Easy to transform Deactivation, Reduced decomposition efficiency. High activated carbon treatment costs; high-quality activated carbon (such as coconut shell activated carbon and coal-based activated carbon) is expensive to purchase and requires regular replacement or regeneration. High regeneration costs: thermal regeneration (high-temperature calcination) is energy-intensive, and chemical regeneration (acid / alkali washing) may generate secondary pollution. High pretreatment requirements: wastewater must first have suspended solids (SS < 10 mg / L) and oils ( < 5 mg / L) removed, otherwise it will easily clog the pores of activated carbon; pH sensitivity: narrow optimal adsorption pH range (e.g., phenols are best adsorbed at pH = 3~5, heavy metals require pH > 6), requiring frequent adjustments. Hydraulic load limitations: contact time must be ≥ 30 minutes, and the equipment occupies a large area. Utility Model Content

[0014] The purpose of this application is to provide a wastewater treatment system for waste tire recycling, so as to solve to some extent the technical problems of existing waste tire recycling pyrolysis wastewater treatment processes, such as being cumbersome and complex, having low efficiency, and requiring a large equipment footprint.

[0015] This application provides a wastewater treatment system for waste tire recycling, including: an oil separator; An air flotation tank, which is connected to the oil separator; A clarification tank, which is connected to the dissolved air flotation tank; A membrane bioreactor, wherein the membrane bioreactor is connected to the clarifier; A reverse osmosis unit, which is connected to the membrane bioreactor.

[0016] In the above technical solution, the wastewater treatment system in the waste tire recycling further includes an equalization tank, the equalization tank includes a first outlet, and the oil separator includes a second inlet and a second outlet, with the first outlet connected to the second inlet. In any of the above technical solutions, the oil separator is further provided with a separation unit and a floating oil collection unit.

[0017] In any of the above technical solutions, the flotation tank further includes a third inlet and a third outlet, wherein the third inlet is connected to the second outlet; The flotation tank also includes a first reagent addition port.

[0018] In any of the above technical solutions, the clarification tank further includes a second reagent addition port, which is used to add reagent to the clarification tank.

[0019] In any of the above technical solutions, the reagent further includes ferric chloride, and the dosage of the ferric chloride is in molar ratio. Add at a ratio of ≥3:1.

[0020] In any of the above technical solutions, the membrane bioreactor further includes a membrane unit with a pore size of 0.01-0.1 μm.

[0021] In any of the above technical solutions, the membrane unit is further described as an antifouling membrane; the membrane flux of the membrane unit is 10~20 LMH.

[0022] In any of the above technical solutions, the reverse osmosis unit further includes a reverse osmosis membrane, and the membrane flux of the reverse osmosis membrane is 12~18 LMH.

[0023] In any of the above technical solutions, the wastewater treatment system in the waste tire recycling further includes a reuse unit, which is connected to the reverse osmosis unit. Compared with the prior art, the beneficial effects of this application are as follows: The wastewater treatment system for waste tire recycling provided in this application includes: an oil separator; an air flotation tank connected to the oil separator; a clarifier connected to the air flotation tank; a membrane bioreactor connected to the clarifier; and a reverse osmosis unit connected to the membrane bioreactor. The wastewater treatment system for waste tire recycling provided in this application offers a complete wastewater treatment process for waste tire recycling pyrolysis, which can effectively remove various impurities and pollutants from the wastewater. This wastewater treatment system for waste tire recycling has a simple structure, is easy to lay out, and occupies a small area. The overall system has low construction and operating costs, high economic efficiency, wide applicability, and strong practicality. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the process flow of the wastewater treatment system in the waste tire recycling provided in the embodiments of this application.

[0026] Figure label: 1-Equalization tank, 101-First inlet, 102-First outlet, 2-Oil separator, 201-Second inlet, 202-Second outlet, 3-Air flotation tank, 301-Third inlet, 302-Third outlet, 4-Clarifier, 401-Fourth inlet, 402-Fourth outlet, 5-Membrane bioreactor, 501-Fifth inlet, 502-Fifth outlet, 6-Reverse osmosis unit, 601-Sixth inlet, 602-Sixth outlet, 7-Reuse unit. Detailed Implementation

[0027] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this application, but not all embodiments.

[0028] The components of the embodiments of this application described and shown in the accompanying drawings can be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of this application provided in the drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application.

[0029] Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0030] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application 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 application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0031] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0032] The following reference Figure 1 This application describes a wastewater treatment system for waste tire recycling as described in an embodiment.

[0033] See Figure 1 As shown, an embodiment of this application provides a wastewater treatment system for waste tire recycling. This wastewater treatment system for waste tire recycling includes an oil separator 2, an air flotation tank 3, a clarifier 4, a membrane bioreactor 5, and a reverse osmosis unit 6 arranged and connected in sequence. Wastewater generated after the thermal cracking of waste tires flows into this wastewater treatment system for waste tire recycling and is treated sequentially through the oil separator 2, air flotation tank 3, clarifier 4, membrane bioreactor 5, and reverse osmosis unit 6.

[0034] Specifically, the wastewater treatment system in this waste tire recycling also includes an equalization tank 1, which is connected to an oil separator 2. The equalization tank 1 is located at the beginning of the wastewater treatment system in this waste tire recycling, and the wastewater to be treated first flows into the equalization tank 1.

[0035] The equalization tank 1 includes a first inlet 101 and a first outlet 102. The wastewater to be treated flows into the equalization tank 1 through the first inlet 101. The equalization tank 1 serves to regulate the water volume and balance the water quality. The oil separator 2 includes a second inlet 201 and a second outlet 202. The first outlet 102 is connected to the second inlet 201. The wastewater in the equalization tank 1 flows into the oil separator 2 through the first outlet 102 and the second inlet 201.

[0036] Furthermore, the oil separator 2 is equipped with a separation unit and an oil floatation collection device. Within the separation unit, floating oil and large suspended solids are separated from the wastewater through gravity settling and the density difference between oil and water. The oil floatation collection device is specifically a skimmer, a common type of skimmer in the art. The skimmer collects the floating oil and large suspended solids and transports them off-site for disposal. Subsequently, the wastewater in the oil separator 2 flows through the second outlet 202 into the flotation tank 3. After treatment by the oil separator 2, the oil content in the effluent from the oil separator 2 can be reduced to <50 mg / L.

[0037] Furthermore, the flotation tank 3 includes a third inlet 301 and a third outlet 302. The third inlet 301 is connected to the second outlet 202 of the oil separator 2. The wastewater treated by the oil separator 2 flows into the flotation tank 3 through the second outlet 202 and the third inlet 301 for further treatment.

[0038] Furthermore, the flotation tank 3 also includes a first reagent addition port for adding chemicals. Through this port, chemicals, specifically PAC (polyaluminum chloride) and PAM (polyacrylamide), can be added to the flotation tank 3 to allow the wastewater to undergo coagulation and flocculation, thereby removing emulsified oil, colloidal substances, and a portion of COD (Chemical Oxygen Demand, often used as a metric for total organic matter). Preferably, the flotation tank 3 is also equipped with another oil skimmer. Within the flotation tank 3, dissolved air water releases microbubbles, causing flocs to float and form scum, which is then removed by the skimmer. This ensures that the effluent oil content of the flotation tank 3 is <10 mg / L and SS (suspended solids) is <30 mg / L.

[0039] Further, the clarifier 4 includes a fourth inlet 401 and a fourth outlet 402. The fourth inlet 401 is connected to the third outlet 302. Wastewater treated by the flotation tank 3 flows into the clarifier 4 through the third outlet 302 and the fourth inlet 401. In the clarifier 4, hardness, suspended solids, heavy metals, sulfides, and part of COD in the wastewater are further removed. The generated sludge settles to the bottom of the clarifier 4, and the clear water flows to the next treatment process. Preferably, in this embodiment, the clarifier 4 is a sludge contact separation type clarifier, which has stable operation, high sedimentation efficiency, high sludge concentration, and excellent effluent quality. Furthermore, the clarifier 4 also includes a second reagent addition port for adding reagents to the clarifier 4. Lime is first added to the clarifier 4 through the second reagent addition port. The pH of the wastewater in clarifier 4 is adjusted to 10.5-11 to promote the removal of heavy metals (such as...) ) forms hydroxide precipitate, while simultaneously promoting the formation of sulfide ions ( Transformed into something that settles more easily. or (Gas phase) to enhance the coagulation effect of subsequent ferric chloride; then, polyferric chloride and coagulant aid are added to clarifier 4, and flocculation reaction takes place in clarifier 4. Ions can react with sulfides in wastewater to produce iron sulfide precipitates that are extremely difficult to dissolve, while... hydrolysis Colloidal substances are used to remove colloidal sulfides and suspended solids through adsorption and trapping. The sludge from the final clarifier 4 settles to the bottom and is discharged, while the clear water overflows to subsequent treatment units. The turbidity of the effluent from clarifier 4 is <2 NTU, and heavy metals meet the standards.

[0040] Furthermore, the membrane bioreactor 5 (MBR) includes a fifth inlet 501 and a fifth outlet 502. The fifth inlet 501 is connected to the fourth outlet 402 of the clarifier 4. Clarified wastewater in the clarifier 4 flows into the MBR through the fourth outlet 402 and the fifth inlet 501. The MBR is equipped with membrane units that use ultrafiltration / microfiltration membranes to directly remove pollutants. Preferably, the pore size of the membrane units is 0.01-0.1 μm. The MBR simultaneously performs biochemical treatment and membrane separation, degrading organic matter in the wastewater and allowing nitrifying bacteria to... Nitrification It achieves an organic matter removal rate of over 95% and an ammonia nitrogen removal rate of over 97%. The sludge age can be very long, significantly improving the degradation efficiency of recalcitrant organic matter. The highly efficient retention of the MBR membrane ensures complete retention of microorganisms within the bioreactor, achieving complete separation of hydraulic retention time (HRT) and sludge time (SRT), resulting in flexible and stable operation control. It boasts advantages such as compact structure, attractive appearance, small footprint, low operating costs, stability and reliability, high degree of automation, and convenient maintenance. It efficiently performs solid-liquid separation, with a separation effect far superior to traditional sedimentation tanks. The effluent quality is excellent, with suspended solids and turbidity approaching zero, allowing for direct reuse or feeding into an RO unit, thus realizing wastewater resource recovery.

[0041] It is evident that, in the waste tire recycling wastewater treatment system provided in the application, the MBR process has significant advantages over the traditional biochemical process in the treatment of waste tire pyrolysis wastewater: (1) It uses ultrafiltration / microfiltration membranes (0.01-0.1μm) to directly intercept pollutants, resulting in excellent effluent quality (SS<1mg / L, CODcr<50mg / L), which can be reused without deep treatment; (2) High sludge concentration (8-15g / L) and long sludge age (SRT>20 days) give it stronger resistance to shock loads. (2) It has a high load capacity and can stably treat high-concentration wastewater (CODcr>2000mg / L); (3) No secondary sedimentation tank and filter are required afterward, which reduces the footprint and allows for more flexible modular design; (4) Sludge production is reduced by 30%-50%, significantly reducing disposal costs; (5) At the same time, the MBR device has a high degree of automation control and more stable and reliable operation; (6) It has a higher removal rate for recalcitrant organic matter (such as PAHs) (up to 80%-90%), making it more suitable for treating waste tire wastewater with complex composition. Its strong resistance to shock loads, good effluent quality, energy saving and consumption reduction and resource recycling benefits make it more competitive in the field of industrial wastewater treatment.

[0042] MBR membrane modules preferably use antifouling membranes, such as PVDF (polyvinylidene fluoride) hollow fiber membranes. During operation, special bacteria can be added to degrade toxic substances such as benzene compounds and sulfides. Preferably, the MBR hydraulic retention time is 6–12 hours, and the membrane flux is 10–20 LMH.

[0043] Furthermore, the reverse osmosis unit 6 includes a sixth inlet 601 and a sixth outlet 602. The sixth inlet 601 is connected to the fifth outlet 502 of the MBR. The water treated by the MBR flows into the reverse osmosis unit 6 through the fifth outlet 502 and the sixth inlet 601. The reverse osmosis unit 6 includes a reverse osmosis membrane (RO membrane), which further cleans the water using the reverse osmosis principle, effectively removing various impurities from the water.

[0044] Preferably, the RO membrane is an anti-fouling reverse osmosis membrane, with a recovery rate designed for 80%, a membrane flux of 12~18 LMH, and a product water TDS < 100 mg / L.

[0045] Furthermore, the wastewater treatment system in this waste tire recycling also includes a reuse unit 7, which is connected to the sixth outlet 602. The clean water produced after treatment by the reverse osmosis unit 6 flows into the reuse unit 7 for reuse.

[0046] Testing showed that the effluent from the wastewater treatment system in this waste tire recycling process meets the following standards:

[0047] In summary, the wastewater treatment system for waste tire recycling provided in this application offers a complete wastewater treatment process for waste tire recycling pyrolysis, which can effectively remove various impurities and pollutants from the wastewater. The effluent quality fully meets the requirements for reuse. This wastewater treatment system for waste tire recycling has a simple structure, is easy to lay out, and occupies a small area. The overall system has low construction and operating costs, high economic efficiency, wide applicability, and strong practicality.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A wastewater treatment system for waste tire recycling, characterized in that, include: Grease trap; An air flotation tank, which is connected to the oil separator; A clarification tank, which is connected to the dissolved air flotation tank; A membrane bioreactor, wherein the membrane bioreactor is connected to the clarifier; A reverse osmosis unit, which is connected to the membrane bioreactor.

2. The wastewater treatment system for waste tire recycling according to claim 1, characterized in that, The wastewater treatment system in the waste tire recycling process also includes an equalization tank, which has a first outlet, and an oil separator, which has a second inlet and a second outlet, with the first outlet connected to the second inlet.

3. The wastewater treatment system for waste tire recycling according to claim 1, characterized in that, The oil separator is equipped with a separation unit and a floating oil collection unit.

4. The wastewater treatment system for waste tire recycling according to claim 2, characterized in that, The flotation tank includes a third inlet and a third outlet, wherein the third inlet is connected to the second outlet; The flotation tank also includes a first reagent addition port.

5. The wastewater treatment system for waste tire recycling according to claim 1, characterized in that, The clarification tank includes a second reagent addition port, which is used to add reagents to the clarification tank.

6. The wastewater treatment system for waste tire recycling according to claim 5, characterized in that, The reagent includes ferric chloride, and the dosage of the ferric chloride is as follows: Add at a ratio of ≥3:

1.

7. The wastewater treatment system for waste tire recycling according to claim 1, characterized in that, The membrane bioreactor includes membrane units with a pore size of 0.01-0.1 μm.

8. The wastewater treatment system for waste tire recycling according to claim 7, characterized in that, The membrane unit is an antifouling membrane; the membrane flux of the membrane unit is 10~20 LMH.

9. The wastewater treatment system for waste tire recycling according to claim 1, characterized in that, The reverse osmosis unit includes a reverse osmosis membrane with a membrane flux of 12~18 LMH.

10. The wastewater treatment system for waste tire recycling according to any one of claims 1 to 9, characterized in that, The wastewater treatment system in the waste tire recycling process also includes a reuse unit, which is connected to the reverse osmosis unit.

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