Organic wastewater treatment system and method for treating organic wastewater

Abstract

An organic wastewater treatment method is provided, comprising: (a) providing a magnetic oxide source and mixing it with the organic wastewater to form a first organic liquid; (b) subjecting the first organic liquid to ultrasonic treatment to produce a second organic liquid comprising magnetic nanoparticles of different sizes and hydrolyzed sludge; (c) separating the second organic liquid by separating the magnetic nanoparticles into first magnetic nanoparticles and second magnetic nanoparticles according to their size, and recirculating the first magnetic nanoparticles to mix with the first organic liquid to continuously subject the first organic liquid to ultrasonic treatment; and (d) using the second magnetic nanoparticles to perform anaerobic biological treatment on the hydrolyzed sludge to convert it into methane. The magnetic oxide source, the first magnetic nanoparticles, and the second magnetic nanoparticles at least comprise magnetic iron oxide.

Description

Technical Field

[0001] This disclosure relates to organic wastewater treatment systems and methods. Prior Technology

[0002] The current manufacturing industry contributes a significant portion of global economic output, but also generates a large amount of waste. As the circular economy becomes mainstream, how to convert waste into resources and reduce carbon emissions is gradually gaining attention from industry and governments.

[0003] The manufacturing industry often generates large amounts of waste sludge during wastewater treatment. Under the environmental protection demands of sustainable development, manufacturing sludge, containing significant amounts of organic waste, is considered a recyclable resource. How to effectively treat and utilize this waste sludge has become a crucial issue for the manufacturing industry. Among current sludge treatment technologies, ultrasonic-based physical pretreatment methods have advantages in reducing environmental pollution, but their power consumption remains a significant challenge.

[0004] As mentioned above, while existing waste sludge treatment technologies can largely meet their original intended uses, they still do not completely satisfy the requirements in every aspect. Developing effective and environmentally friendly sludge reduction and reuse technologies for organic wastewater treatment has become a core issue for the manufacturing industry. Furthermore, developing efficient and low-energy-consumption low-carbon treatment technologies to achieve the resource and energy recovery of waste sludge remains a focus of attention in related fields. Summary of the Invention

[0005] According to some embodiments disclosed herein, an organic wastewater treatment method is provided, comprising the following steps: (a) providing a magnetic oxide source and mixing it with organic wastewater to form a first organic liquid comprising the magnetic oxide source and organic wastewater; (b) subjecting the first organic liquid to ultrasonic treatment to produce a second organic liquid comprising magnetic nanoparticles of different sizes and hydrolyzed sludge; (c) separating the second organic liquid by separating the magnetic nanoparticles of different sizes into first magnetic nanoparticles and second magnetic nanoparticles according to their size, wherein the first magnetic nanoparticles are recirculated to mix with the first organic liquid to continuously subject the first organic liquid to ultrasonic treatment; and (d) using the second magnetic nanoparticles to perform anaerobic biological treatment on the hydrolyzed sludge to convert it into methane. Furthermore, the magnetic oxide source, the first magnetic nanoparticles, and the second magnetic nanoparticles at least comprise magnetic iron oxide.

[0006] According to some embodiments disclosed herein, an organic wastewater treatment system is also provided, comprising: a feeding unit, a magnetic oxide feed source supply unit, an ultrasonic treatment unit, a separation unit, and an anaerobic biological treatment unit. The feeding unit provides organic wastewater. The magnetic oxide feed source supply unit, connected to the feeding unit, provides a magnetic oxide feed source, which mixes with the organic wastewater to form a first organic liquid comprising the magnetic oxide feed source and the organic wastewater. The ultrasonic treatment unit, connected to the feeding unit, ultrasonically treats the first organic liquid to produce a second organic liquid comprising magnetic nanoparticles of different sizes and hydrolyzed sludge. The separation unit, connected to the ultrasonic treatment unit, separates the magnetic nanoparticles of different sizes into first magnetic nanoparticles and second magnetic nanoparticles according to their size. The first magnetic nanoparticles are returned upstream of the ultrasonic treatment unit to mix with the first organic liquid for continuous ultrasonic treatment of the first organic liquid. The anaerobic biological treatment unit is connected to the separation unit, and the second magnetic nanoparticles anaerobically treat the hydrolyzed sludge in the anaerobic biological treatment unit to convert it into methane. Furthermore, the magnetic oxide material source, the first magnetic nanoparticle, and the second magnetic nanoparticle contain at least magnetic iron oxide.

[0007] To make the features or advantages of this disclosure more apparent and understandable, several embodiments are described below in detail with reference to the accompanying drawings. Simple Explanation of the Diagram

[0008] Figure 1 shows a schematic diagram of an organic wastewater treatment system according to some embodiments of this disclosure; Figure 2 shows a flowchart of the steps of an organic wastewater treatment method according to some embodiments of this disclosure; Figure 3 shows the test results of the effect of adding magnetic iron oxide on the treatment efficiency of organic sludge according to some embodiments of this disclosure; Figure 4 shows the test results of the effect of adding magnetic iron oxide on the treatment efficiency of organic sludge according to some embodiments of this disclosure; Figure 5A shows the test results of the effect of the ultrasonic processing unit on the particle nano-sizing of magnetic iron oxide material source according to some embodiments of this disclosure; Figure 5B shows the test results of the effect of the ultrasonic processing unit on the particle nanofiber of the magnetic iron oxide material source according to some embodiments of this disclosure; Figure 6A shows the test results of the effect of nano-magnetic iron oxide on the methane yield of an anaerobic biological treatment unit according to some embodiments of this disclosure; Figure 6B shows the test results of the effect of nano-magnetic iron oxide on the methane yield of an anaerobic biological treatment unit according to some embodiments of this disclosure; Figure 7 shows the test results of the overall effect of adding magnetic iron oxide feedstock on the methane yield of an organic wastewater treatment system, according to some embodiments of this disclosure. Implementation

[0009] The following provides a detailed description of the organic wastewater treatment system and method according to embodiments of this disclosure. It should be understood that the following description provides many different embodiments or examples to implement different variations of some embodiments of this disclosure. The specific elements and arrangements described below are merely for simple and clear description of some embodiments of this disclosure. Of course, these are only examples and not limitations of this disclosure.

[0010] This disclosure of embodiments can be understood in conjunction with the accompanying drawings, which are also considered part of the disclosure description. It should be understood that the drawings in this disclosure are not drawn to scale; in fact, the dimensions of the components may be arbitrarily enlarged or reduced to clearly show the features of this disclosure.

[0011] In this text, the phrase "the range is between the first value and the second value" means that the range includes the first value, the second value, and other values ​​in between.

[0012] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It is understood that these terms, for example, as defined in commonly used dictionaries, should be interpreted as having a meaning consistent with the relevant art and the background or context of this disclosure, and should not be interpreted in an idealized or overly formal manner, unless specifically defined in the embodiments of this disclosure.

[0013] In response to the current industry's demand for organic wastewater reduction and the market demand for related technologies, products, and services, this disclosure provides an organic wastewater treatment method that can simultaneously improve sludge pretreatment efficiency and methane yield. By adding magnetic oxide feedstock and combining it with wastewater treatment process scheduling, the oxide feedstock acts as an ultrasonic abrasive and a biochemical metabolic catalyst at different stages of wastewater treatment. This synergistically enhances the existing ultrasonic sludge hydrolysis technology and the subsequent anaerobic biological metabolism's organic matter conversion function, achieving the effect of simultaneously improving sludge pretreatment efficiency and methane yield. This allows for more energy-efficient and high-efficiency treatment of organic wastewater.

[0014] Figure 1 shows a schematic diagram of an organic wastewater treatment system 1S according to some embodiments of this disclosure. It should be understood that, for clarity, some components of the organic wastewater treatment system 1S are omitted from the figure, and only some components are schematically depicted. According to some embodiments, additional features may be added to the organic wastewater treatment system 1S described below. The dashed arrows in the figure represent the direction of material transport between the units in the organic wastewater treatment system 1S.

[0015] Please refer to Figure 1. The organic wastewater treatment system 1S may include a feeding unit 10, a magnetic oxide material supply unit 20, an ultrasonic treatment unit 30, a separation unit 40, and an anaerobic biological treatment unit 50.

[0016] Feeding unit 10 can provide organic wastewater WT. Organic wastewater WT includes organic sludge. According to some embodiments, organic wastewater WT may include wastewater from the food industry, manufacturing industry, petrochemical industry, agriculture, animal husbandry, other sources of wastewater containing organic matter, or combinations thereof, but is not limited thereto.

[0017] A magnetic oxide source supply unit 20 is connected to a feeding unit 10. According to some embodiments, the magnetic oxide source supply unit 20 may be located downstream of the feeding unit 10. According to other embodiments, the magnetic oxide source supply unit 20 may be located upstream of the feeding unit 10. The magnetic oxide source supply unit 20 can provide a magnetic oxide source MO, which is then mixed with organic wastewater WT to form a first organic liquid O1 comprising the magnetic oxide source MO and the organic wastewater WT. The first organic liquid O1 may be a homogeneous organic liquid formed by mixing the magnetic oxide source MO and the organic wastewater WT.

[0018] The magnetic oxide source MO may comprise magnetic iron oxide. According to some embodiments, the magnetic iron oxide may comprise magnetite (Fe3O4), ferrous oxide (FeO), ferric oxide (Fe2O3), or a combination thereof, but is not limited thereto. According to some embodiments, the size (particle size) of the magnetic oxide source MO can be between 200 nanometers (nm) and 5 micrometers (μm), for example, between 300 nanometers and 4.8 micrometers, between 500 nanometers and 4.5 micrometers, between 800 nanometers and 4.2 micrometers, or between 1 micrometer and 4 micrometers, or for example, between 250 nanometers, 350 nanometers, 450 nanometers, 550 nanometers, 650 nanometers, 750 nanometers, 850 nanometers, 950 nanometers, 1.2 micrometers, 1.5 micrometers, 1.8 micrometers, 2 micrometers, 2.3 micrometers, 2.5 micrometers, 2.7 micrometers, 3 micrometers, 3.25 micrometers, 3.5 micrometers, or 3.75 micrometers, but is not limited thereto.

[0019] Furthermore, according to some embodiments, the magnetic oxide source supply unit 20 can directly provide a magnetic oxide source MO that has not undergone nano-processing, such as a crude source of magnetic iron oxide, thus omitting the nano-processing step of the magnetic oxide source MO, thereby simplifying the process and reducing costs. In particular, according to some embodiments, the magnetic oxide source MO can be a byproduct derived from a steel plant (e.g., a product generated from a pickling process), thereby realizing the energy recovery of waste resources.

[0020] The ultrasonic processing unit 30 can be connected to the feeding unit 10. The ultrasonic processing unit 30 can be located downstream of the feeding unit 10 and the magnetic oxide material source supply unit 20. The ultrasonic processing unit 30 can ultrasonically treat a first organic liquid O1 containing magnetic oxide material source MO and organic wastewater WT to produce a second organic liquid O2 containing magnetic nanoparticles P0 of different sizes and hydrolyzed sludge HS. According to some embodiments, the feeding unit 10 and the magnetic oxide material source supply unit 20 are respectively connected to the ultrasonic processing unit 30 via connectors L.

[0021] According to some embodiments, the output power of the ultrasonic processing performed in the ultrasonic processing unit 30 may be between 300 watts and 1200 watts, for example, between 350 watts and 1150 watts, or between 400 watts and 1100 watts, or for example, 450 watts, 500 watts, 550 watts, 600 watts, 650 watts, 700 watts, 750 watts, 800 watts, 900 watts, 950 watts, 1000 watts, or 1050 watts, but is not limited thereto. According to some embodiments, the frequency of the ultrasonic processing performed in the ultrasonic processing unit 30 may be between 20 kHz and 100 kHz, for example, between 20 kHz and 90 kHz or between 25 kHz and 80 kHz, or for example, 25 kHz, 30 kHz, 35 kHz, 40 kHz, 45 kHz, 50 kHz, 55 kHz, 60 kHz, 65 kHz, 70 kHz, 75 kHz, 80 kHz or 85 kHz, but is not limited thereto.

[0022] It is worth noting that the coarse source of magnetic oxide material MO (size greater than 200 nanometers) can be used as an abrasive for ultrasonic treatment to enhance the sonochemistry of ultrasound on the sludge, thereby improving hydrolysis efficiency and thus increasing the yield of hydrolyzed sludge HS. At the same time, the magnetic oxide material MO after several ultrasonic oscillations will begin to break down, forming magnetic nanoparticles PO of different sizes with normal distribution.

[0023] Furthermore, the separation unit 40 can be connected to the ultrasonic processing unit 30. The separation unit 40 can be located downstream of the ultrasonic processing unit 30. The separation unit 40 can separate magnetic nanoparticles P0 of different sizes into first magnetic nanoparticles P1 and second magnetic nanoparticles P2 according to their size, and the first magnetic nanoparticles P1 will flow back to the upstream of the ultrasonic processing unit 30 to mix with the first organic liquid O1, so as to continuously perform ultrasonic processing on the first organic liquid O1.

[0024] The first magnetic nanoparticle P1 and the second magnetic nanoparticle P2 are formed by ultrasonic treatment of a magnetic oxide source MO. Both the first magnetic nanoparticle P1 and the second magnetic nanoparticle P2 also contain magnetic iron oxide. According to some embodiments, the magnetic iron oxide may contain magnetite (Fe3O4), ferrous oxide (FeO), ferric oxide (Fe2O3), or combinations thereof, but is not limited thereto. Specifically, the size of the first magnetic nanoparticle P1 may be larger than the size of the second magnetic nanoparticle P2. According to some embodiments, the size of the first magnetic nanoparticle P1 can be between 200 nanometers and 5 micrometers, for example, between 300 nanometers and 4.8 micrometers, between 500 nanometers and 4.5 micrometers, between 800 nanometers and 4.2 micrometers, or between 1 micrometer and 4 micrometers. For example, it can be 250 nanometers, 350 nanometers, 450 nanometers, 550 nanometers, 650 nanometers, 750 nanometers, 850 nanometers, 950 nanometers, 1.2 micrometers, 1.5 micrometers, 1.8 micrometers, 2 micrometers, 2.3 micrometers, 2.5 micrometers, 2.7 micrometers, 3 micrometers, 3.25 micrometers, 3.5 micrometers, or 3.75 micrometers, but is not limited thereto. According to some embodiments, the size of the second magnetic nanoparticle can be between 20 nanometers and 200 nanometers, for example, between 30 nanometers and 190 nanometers, or between 40 nanometers and 180 nanometers, or for example, 50 nanometers, 60 nanometers, 70 nanometers, 75 nanometers, 80 nanometers, 85 nanometers, 90 nanometers, 100 nanometers, 110 nanometers, 120 nanometers, 130 nanometers, 140 nanometers, 150 nanometers, 160 nanometers or 170 nanometers, but is not limited thereto.

[0025] According to some embodiments, the separation unit 40 can be a gravity sedimentation separation device or a magnetic adsorption separation device. It is noteworthy that the separation unit 40 can separate the coarser first magnetic nanoparticles P1 and the finer second magnetic nanoparticles P2. The coarse particles (size greater than 200 nanometers) of the first magnetic nanoparticles P1 are returned to the ultrasonic treatment unit 30 for continued use as an abrasive, while the fine particles (size less than 200 nanometers) of the second magnetic nanoparticles P2 are introduced together with the hydrolyzed sludge HS into the subsequent anaerobic biological treatment unit 50. This serves as an accelerator for interspecies electron transfer (IET) in the anaerobic digestion reaction, enhancing extracellular electron transfer in microorganisms, alleviating the inhibition caused by high organic loading rates, organic acids, and toxic substances, effectively degrading complex organic matter, and overcoming the problems of low electron transfer efficiency and acidification in traditional anaerobic digestion.

[0026] As described above, the first magnetic nanoparticle P1 flows back upstream of the ultrasonic processing unit 30 to mix with the first organic liquid O1, thereby continuously ultrasonically treating the first organic liquid O1, while the second magnetic nanoparticle P2 is transferred to the anaerobic biological processing unit 50 for continued anaerobic biological treatment. According to some embodiments, the ultrasonic processing unit 30 and the separation unit 40 are connected by connectors L. Specifically, according to some embodiments, the ultrasonic processing unit 30 is located upstream of the separation unit 40, and the separation unit 40 has a connector L (denoted as connector L1 for ease of explanation) connected downstream of the ultrasonic processing unit 30. Furthermore, according to some embodiments, the separation unit 40 further has a connector L (denoted as connector L2 for ease of explanation) connected upstream of the ultrasonic processing unit 30 and a connector L (denoted as connector L3 for ease of explanation) connected upstream of the anaerobic biological processing unit 50.

[0027] The anaerobic biological treatment unit 50 can be connected to the separation unit 40. The anaerobic biological treatment unit 50 can be located downstream of the separation unit 40. Second magnetic nanoparticles P2 can enhance the anaerobic biological treatment of hydrolyzed sludge HS by microorganisms in the anaerobic biological treatment unit 50 to convert it into methane MT, which can then be converted into electricity by subsequent biogas power generation facilities. Specifically, anaerobic biological treatment can decompose and convert small-molecule organic matter into biogas, such as methane, through the biochemical metabolism of microorganisms. According to some embodiments, the anaerobic biological treatment unit 50 may include an anaerobic fermentation tank, which may contain hydrolytic bacteria, acid-forming bacteria, methanogens, other suitable bacterial species, or combinations thereof, but is not limited to these.

[0028] According to some embodiments, anaerobic biological treatment can be carried out at temperatures between 25°C and 45°C, for example, at temperatures between 27°C and 42°C or between 30°C and 40°C, or for example, at temperatures of 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, or 39°C, but is not limited thereto. According to some embodiments, anaerobic biological treatment can be carried out at pH conditions between pH 6.8 and pH 7.2, for example, at pH 6.9, pH 7, or pH 7.1, but is not limited thereto.

[0029] Furthermore, this disclosure also provides an organic wastewater treatment method 1M. Please refer to Figure 2, which shows a flowchart of the steps of the organic wastewater treatment method 1M according to some embodiments of this disclosure. According to some embodiments, the organic wastewater treatment method 1M includes treating organic waste using the aforementioned organic wastewater treatment system 1S, but this disclosure is not limited thereto. It should be understood that, according to some embodiments, additional steps may be added before, during, and / or after the organic wastewater treatment method 1M described below, or some steps may be replaced or omitted.

[0030] As shown in Figure 2, the organic wastewater treatment method 1M may include step S1: providing a magnetic oxide source MO and mixing it with organic wastewater WT to form a first organic liquid O1 containing the magnetic oxide source MO and the organic wastewater WT.

[0031] The first organic liquid O1 can be a homogeneous organic liquid composed of a magnetic oxide source MO and organic wastewater WT. According to some embodiments, the weight-volume percentage (w / v) of the magnetic oxide source MO to the organic wastewater WT is between 0.01% and 1%, for example, between 0.05% and 1%, or between 0.1% and 1%, or for example, 0.01%, 0.02%, 0.03%, 0.05%, 0.08%, 0.1%, 0.2%, 0.3%, 0.5%, 0.75%, 0.85%, or 1%, but is not limited thereto. It is worth noting that when the weight-volume percentage (w / v) of the magnetic oxide source MO to the organic wastewater WT is within the above range, the efficiency of subsequent ultrasonic treatment and anaerobic biological treatment can be effectively improved. For example, this can increase the overall digestion rate of organic sludge, thereby shortening the digestion time of organic sludge and increasing the biogas methane generation rate.

[0032] The magnetic oxide source MO may comprise magnetic iron oxide. According to some embodiments, the magnetic iron oxide may comprise magnetite (Fe3O4), ferrous oxide (FeO), ferric oxide (Fe2O3), or a combination thereof, but is not limited thereto. According to some embodiments, the size (particle size) of the magnetic oxide source MO can be between 200 nanometers (nm) and 5 micrometers (μm), for example, between 300 nanometers and 4.8 micrometers, between 500 nanometers and 4.5 micrometers, between 800 nanometers and 4.2 micrometers, or between 1 micrometer and 4 micrometers, or for example, between 250 nanometers, 350 nanometers, 450 nanometers, 550 nanometers, 650 nanometers, 750 nanometers, 850 nanometers, 950 nanometers, 1.2 micrometers, 1.5 micrometers, 1.8 micrometers, 2 micrometers, 2.3 micrometers, 2.5 micrometers, 2.7 micrometers, 3 micrometers, 3.25 micrometers, 3.5 micrometers, or 3.75 micrometers, but is not limited thereto.

[0033] According to some embodiments, the magnetic oxide source MO can be a crude source of magnetic oxides, such as a crude source of magnetic iron oxide, eliminating the need for pre-nano-processing of the magnetic oxide source MO, thereby simplifying the process and reducing costs. In particular, according to some embodiments, the magnetic oxide source MO can be a byproduct derived from a steel plant (e.g., a product generated from a pickling process), thereby realizing the energy recovery of waste resources.

[0034] Organic wastewater (WT) includes organic sludge. According to some embodiments, organic wastewater (WT) may include wastewater from the food industry, manufacturing industry, petrochemical industry, agriculture, animal husbandry, other sources of wastewater containing organic matter, or combinations thereof, but is not limited thereto.

[0035] Furthermore, the organic wastewater treatment method 1M may include step S2: ultrasonically treating the first organic liquid to produce a second organic liquid O2 containing magnetic nanoparticles P0 of different sizes and hydrolyzed sludge HS. Specifically, when ultrasound is used to perform a hydrolysis process on the organic-containing liquid, the impact force generated by the cavitation effect breaks down the outer layer (e.g., cell walls) of the organic sludge, causing the release of organic matter from the sludge and increasing the concentration of dissolved organic matter in the organic liquid.

[0036] According to some embodiments, the output power of the ultrasonic processing can be between 300 watts and 1200 watts, for example, between 350 watts and 1150 watts, or between 400 watts and 1100 watts, or for example, 450 watts, 500 watts, 550 watts, 600 watts, 650 watts, 700 watts, 750 watts, 800 watts, 900 watts, 950 watts, 1000 watts, or 1050 watts, but is not limited thereto. According to some embodiments, the frequency of the ultrasound treatment can be between 20 kHz and 100 kHz, for example, between 20 kHz and 90 kHz or between 25 kHz and 80 kHz, or for example, 25 kHz, 30 kHz, 35 kHz, 40 kHz, 45 kHz, 50 kHz, 55 kHz, 60 kHz, 65 kHz, 70 kHz, 75 kHz, 80 kHz or 85 kHz, but is not limited thereto. Furthermore, according to some embodiments, the duration of the ultrasound treatment can be between 1 minute and 20 minutes, for example, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes or 19 minutes, but is not limited thereto.

[0037] It is worth noting that the coarse source of magnetic oxide material MO (size greater than 200 nanometers) can be used as an abrasive for ultrasonic treatment to enhance the sonochemical effect of ultrasound on sludge, thereby improving hydrolysis efficiency and thus increasing the yield of hydrolyzed sludge HS; at the same time, the magnetic oxide material MO after several ultrasonic oscillations will begin to break down, forming magnetic nanoparticles PO of different sizes with normal distribution.

[0038] Furthermore, the organic wastewater treatment method 1M may include step S3: separating the second organic liquid O2, separating magnetic nanoparticles P0 of different sizes into first magnetic nanoparticles P1 and second magnetic nanoparticles P2 according to their size, and recirculating the first magnetic nanoparticles P1 to mix with the first organic liquid O1, so as to continuously treat the first organic liquid O1 with ultrasound.

[0039] A magnetic oxide source MO is ultrasonically processed to form first magnetic nanoparticles P1 and second magnetic nanoparticles P2, both of which contain magnetic iron oxide. According to some embodiments, the magnetic iron oxide may contain magnetite (Fe3O4), ferrous oxide (FeO), ferric oxide (Fe2O3), or combinations thereof, but is not limited thereto. Specifically, the size of the first magnetic nanoparticle P1 may be larger than the size of the second magnetic nanoparticle P2. According to some embodiments, the size of the first magnetic nanoparticle P1 can be between 200 nanometers and 5 micrometers, for example, between 300 nanometers and 4.8 micrometers, between 500 nanometers and 4.5 micrometers, between 800 nanometers and 4.2 micrometers, or between 1 micrometer and 4 micrometers. For example, it can be 250 nanometers, 350 nanometers, 450 nanometers, 550 nanometers, 650 nanometers, 750 nanometers, 850 nanometers, 950 nanometers, 1.2 micrometers, 1.5 micrometers, 1.8 micrometers, 2 micrometers, 2.3 micrometers, 2.5 micrometers, 2.7 micrometers, 3 micrometers, 3.25 micrometers, 3.5 micrometers, or 3.75 micrometers, but is not limited thereto. According to some embodiments, the size of the second magnetic nanoparticle can be between 20 nanometers and 200 nanometers, for example, between 30 nanometers and 190 nanometers, or between 40 nanometers and 180 nanometers, or for example, 50 nanometers, 60 nanometers, 70 nanometers, 75 nanometers, 80 nanometers, 85 nanometers, 90 nanometers, 100 nanometers, 110 nanometers, 120 nanometers, 130 nanometers, 140 nanometers, 150 nanometers, 160 nanometers or 170 nanometers, but is not limited thereto.

[0040] According to some embodiments, the separation process can be gravity sedimentation separation or magnetic adsorption separation. It is noteworthy that the separation process can separate the coarser first magnetic nanoparticles P1 and the finer second magnetic nanoparticles P2. The coarse particles (size greater than 200 nanometers) of the first magnetic nanoparticles P1 are recirculated to be mixed with the first organic liquid O1 for ultrasonic treatment and reused as an abrasive. The fine particles (size less than 200 nanometers) of the second magnetic nanoparticles P2 are introduced together with the hydrolyzed sludge HS into the subsequent anaerobic biological treatment (step S4) as an interspecies electron transfer (IET) promoter for microorganisms in the anaerobic digestion reaction. This enhances extracellular electron transfer in microorganisms, alleviates the inhibition caused by high organic loading rates, organic acids, and toxic substances, effectively degrades complex organic matter, and overcomes the problems of low electron transfer efficiency and acidification in traditional anaerobic digestion.

[0041] Furthermore, the organic wastewater treatment method 1M may include step S4: anaerobic biological treatment of hydrolyzed sludge HS with second magnetic nanoparticles P2 to convert it into methane MT. Methane MT can be converted into electricity by subsequent biogas power generation facilities. Specifically, anaerobic biological treatment can decompose and convert small-molecule organic matter into biogas, such as methane, through the biochemical metabolism of microorganisms. According to some embodiments, anaerobic biological treatment may include the use of hydrolytic bacteria, acid-forming bacteria, methanogens, other suitable bacterial species, or combinations thereof, but is not limited to these. As mentioned above, the second magnetic nanoparticles P2 can act as an interspecies electron transfer (IET) promoter to improve the efficiency of anaerobic biological treatment.

[0042] According to some embodiments, anaerobic biological treatment can be carried out at temperatures between 25°C and 45°C, for example, at temperatures between 27°C and 42°C or between 30°C and 40°C, or for example, at temperatures of 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, or 39°C, but is not limited thereto. According to some embodiments, anaerobic biological treatment can be carried out at pH conditions between pH 6.8 and pH 7.2, for example, at pH 6.9, pH 7, or pH 7.1, but is not limited thereto.

[0043] Furthermore, according to some embodiments, the aforementioned organic wastewater treatment method 1M includes continuous operation steps S2 to S4 at least 5 to 20 times. For example, steps S2 to S4 can be cycled 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 or 19 times, but is not limited thereto.

[0044] To make the above and other objects, features and advantages of this disclosure more apparent and understandable, several embodiments and comparative examples are described in detail below, but they are not intended to limit the scope of this disclosure.

[0045] [Example]

[0046] [Example] [1-] [The effect of adding magnetic oxide material on ultrasonic processing efficiency]

[0047] Magnetic iron oxide was used as the source of magnetic oxides and as an abrasive added to the ultrasonic treatment unit for sludge pretreatment. Specifically, waste organic matter (organic wastewater containing approximately 5% biological sludge from a manufacturing wastewater plant) was mixed with magnetic iron oxide (commercially available coarse source (200nm~5µm) magnetic iron oxide (Fe3O4) granular powder) to form a homogeneous organic liquid (the weight / volume percentage (w / v) of magnetic iron oxide to waste organic matter ranged from 0.01% to 1%). This organic liquid was then subjected to ultrasonic treatment. The ultrasonic output power ranged from 300 watts to 1200 watts, and the frequency ranged from 20 kHz to 100 kHz. After the reaction, the concentration of dissolved organic matter (chemical oxygen demand, COD) in the ultrasonically treated hydrolysate was measured. This data was used to determine the pretreatment effect of the waste organic matter. Dissolved organic matter (COD) concentration is an indicator of the effectiveness of pretreatment of waste organic matter before anaerobic biological treatment. It is usually represented by the concentration of organic matter in a liquid (unit: mg / L).

[0048] Specifically, in this experiment, 3000 ml of organic wastewater (waste organic matter) containing organic sludge was taken, with a suspended solids (SS) concentration of approximately 50185 mg / L and a volatile suspended solids (VSS) concentration of approximately 36625 mg / L. This was divided into six equal portions, each 500 ml. Then, coarse source magnetic iron oxide (Fe3O4) granular powder was added to each portion, resulting in magnetic iron oxide concentrations (w / v percentage of magnetic iron oxide to waste organic matter) of 0%, 0.01%, 0.05%, 0.1%, 0.5%, and 1% respectively in the six portions. After mixing, the mixture was ultrasonically treated at 20 kHz frequency and 500 watts power for 5 minutes, and the change in dissolved organic matter concentration was then measured.

[0049] The experimental results are shown in Figure 3. From left to right, the figures represent six reaction samples with added magnetic iron oxide (Fe3O4) concentrations of 0%, 0.01%, 0.05%, 0.1%, 0.5%, and 1%, respectively. The dissolved organic matter concentrations after ultrasonic treatment were approximately 12623 mg / L, 13638 mg / L, 15008 mg / L, 19012 mg / L, 20188 mg / L, and 21215 mg / L, respectively. The results show that the ultrasonic treatment efficiency increases with the concentration of magnetic iron oxide used as an abrasive. Specifically, compared to the group without added magnetic iron oxide (0% concentration), the dissolved organic matter concentration was significantly increased by approximately 51% under the normal wastewater treatment condition of adding 0.1% magnetic iron oxide. When the concentration of magnetic iron oxide is increased to 1%, the concentration of soluble organic matter can be significantly increased to about 68%.

[0050] [Example] [2-] [The effect of adding magnetic oxide material on ultrasonic processing efficiency]

[0051] As described in Example 1, the waste organic matter to be treated was divided into two parts. One part was not treated with magnetic iron oxide, and the other part was treated with coarse source magnetic iron oxide (Fe3O4) granule powder with a concentration of 0.1%. After mixing, the two parts were treated with ultrasound at a frequency of 20 kHz and a power of 500 watts for 0 to 15 minutes respectively. The change in the concentration of dissolved organic matter (COD) after 0 to 15 minutes of ultrasound treatment was then measured.

[0052] The experimental results are shown in Figure 4. Under the same reaction conditions, using magnetic iron oxide particles as an abrasive for ultrasonic hydrolysis of organic sludge showed significant differences compared to ultrasonic hydrolysis without magnetic iron oxide. Specifically, to achieve a peak dissolved organic matter (COD) concentration of approximately 19,000 mg / L, the group without magnetic iron oxide (shown as no abrasive) required 13 minutes of treatment, while the group with 0.1% magnetic iron oxide (shown as abrasive) only required 5 minutes. Furthermore, based on achieving the peak COD concentration as the baseline for completing one reaction, and assuming a treatment time of 8.3W per minute, the group without magnetic iron oxide consumed 107.9W, while the group with magnetic iron oxide consumed only 41.5W. These results indicate that using magnetic iron oxide particles as an abrasive resulted in at least 62% energy savings for the ultrasonic treatment unit.

[0053] [Example] [3-] [Influence Analysis of Ultrasonic Processing Unit on Particle Nanoforming of Magnetic Iron Oxide Source] [(] [The impact of ultrasonic treatment time and the impact of wastewater sludge concentration] [)]

[0054] As described in Example 1, the waste organic matter to be treated was divided into 4 portions, and each portion was added with coarse source magnetic iron oxide (Fe3O4) particle powder to a concentration of 0.1%. After mixing, the mixture was treated with ultrasound at a frequency of 20 kHz and a power of 500 watts for 0 minutes, 2.5 minutes, 5 minutes and 10 minutes respectively. The change in the proportion of magnetic iron oxide (Fe3O4) particles contained in the hydrolyzed sludge produced after ultrasonic treatment was then measured.

[0055] The experimental results are shown in Figure 5A. The results indicate that the magnetic iron oxide (Fe3O4) underwent nano-nanoization after ultrasonic treatment, categorized into three particle size ranges: less than 20 nm, 20 to 200 nm, and greater than 200 nm. The proportion of each particle size range after ultrasonic treatment was observed, with the formation of 20–200 nm particles as a reference indicator for nano-nanoization. The results show that after 10 minutes of ultrasonic treatment, significant nano-nanoization of the magnetic iron oxide occurred, with particles of 20–200 nm accounting for at least approximately 71%. Furthermore, the values ​​in the figure show that in the ultrasonic sludge pretreatment reaction, the nano-nanoization of coarse-source magnetic iron oxide increases with increasing ultrasonic treatment time.

[0056] Furthermore, as described in Example 1, organic wastewater containing 0%, 2.5%, 5%, and 10% biological sludge (suspended solids) was taken respectively. Each of these four portions of waste organic matter to be treated was mixed with coarse source magnetic iron oxide (Fe3O4) particle powder to a concentration of 0.1%. After mixing, each portion was treated with an ultrasonic wave at a frequency of 20 kHz and a power of 500 watts for 5 minutes. The change in the proportion of magnetic iron oxide (Fe3O4) particles in the hydrolyzed sludge produced after ultrasonic treatment was then measured.

[0057] The experimental results are shown in Figure 5B. The results indicate that the magnetic iron oxide (Fe3O4) underwent nano-sizing after ultrasonic treatment, differentiated into three particle size ranges: less than 20 nm, 20 to 200 nm, and greater than 200 nm. The proportion of each particle size range after ultrasonic treatment was observed, with the formation of 20–200 nm particles as a reference indicator for nano-sizing. The results show that in organic wastewater containing 5% biological sludge, nano-sizing of magnetic iron oxide was significant, with particles of 20–200 nm accounting for at least approximately 55%. Furthermore, the values ​​in the figure show that in the ultrasonic sludge pretreatment reaction, the nano-nanoization of coarse magnetic iron oxide increases with the increase of wastewater sludge concentration when the biological sludge content is below 5%. However, the nano-nanoization degree of magnetic iron oxide cannot be increased when the biological sludge content exceeds 5%. The nano-nanoization degree of 10% biological sludge content (with the proportion of particle size of 20~200 nm as a reference index) is actually lower than that of 5% biological sludge content.

[0058] [Example] [4-] [Analysis of the impact of nano-magnetic iron oxide on methane yield in anaerobic biological treatment units] [(] [The influence of the size of magnetic iron oxide and the influence of the amount of magnetic iron oxide added] [)]

[0059] The methane generation experiment included the following steps: The experiment was divided into four groups, each with an identical 600 ml reaction vessel. The reaction vessels were prepared with either no additives or additives of the same concentration (0.01%) of magnetic iron oxide (Fe3O4) with different particle sizes: less than 20 nm, 20-200 nm, and greater than 200 nm. Each group also added 350 ml of organic hydrolyzed sludge substrate, followed by 150 ml of plant sludge. The reaction conditions were set at 35°C and pH 7.0 for batch anaerobic digestion experiments. A gas collection hole was installed above the reaction vessel cover, and a gas flow meter was used to collect the methane gas produced by the decomposition of the organic hydrolyzed sludge. The reaction was carried out with continuous stirring for at least 7 days, and the cumulative gas production of individual test samples was recorded.

[0060] The experimental results are shown in Figure 6A. The cumulative methane production of the four experimental groups were 203 ml, 158 ml, 327 ml, and 225 ml, respectively. Compared with the group without magnetic iron oxide (No Add), the groups with magnetic iron oxide particles of 20 to 200 nanometers (20~200 nm) and those with particles larger than 200 nanometers (>200 nm) saw an increase in methane production of 61% and 11%, respectively, while the groups with magnetic iron oxide particles smaller than 20 nanometers (<20 nm) experienced a decrease of 22%. The results indicate that in the anaerobic biological unit of wastewater treatment, the addition of magnetic iron oxide with a particle size of 20 to 200 nanometers can significantly increase methane production by up to 1.6 times. In other words, the addition of nano-sized magnetic iron oxide with a specific particle size (20~200 nm) can act as an interspecies electron transfer (IET) promoter, effectively increasing methane production.

[0061] Furthermore, using the same experimental method as described above, under the same reaction conditions, magnetic iron oxide with a particle size of 20 to 200 nanometers was added at different dosages, divided into 7 groups: 0%, 0.005%, 0.01%, 0.05%, 0.1%, 0.5%, and 1%. After the anaerobic biological reaction, the cumulative amount of gas produced by individual test samples was recorded to observe the effect of the amount of magnetic iron oxide with a particle size of 20 to 200 nanometers added on the methane yield.

[0062] The experimental results are shown in Figure 6B. The cumulative methane production of the seven experimental groups with 0%, 0.005%, 0.01%, 0.05%, 0.1%, 0.5%, and 1% magnetic iron oxide were 205 ml, 245 ml, 323 ml, 318 ml, 305 ml, 236 ml, and 211 ml, respectively. Compared with the group without magnetic iron oxide (0%), the addition of specific doses (0.005–0.1%) of nano-magnetic iron oxide as an interspecific electron transfer (IET) promoter effectively increased methane production, with the group adding 0.01% showing the most significant increase in methane production, at least approximately 58%.

[0063] [Example] [5-] [The overall impact of adding magnetic iron oxide feedstock on methane yield in organic wastewater treatment systems]

[0064] Similar to the ultrasonic treatment method described in Example 1, and combined with the anaerobic biological treatment method of Example 4, magnetic iron oxide was introduced into the wastewater treatment process to observe its overall impact on the conversion of organic wastewater into methane in the organic wastewater treatment system. Using the best-practice parameters demonstrated in the above examples, 0.1% magnetic iron oxide (Fe3O4, 200nm~5µm) was added to the ultrasonic treatment unit, while 0.01% magnetic iron oxide (Fe3O4, 20~200nm) was introduced into the anaerobic biological treatment unit. After the reaction in the organic wastewater treatment system, the final methane production amount and rate were measured as an assessment of the overall efficiency of organic matter conversion into methane.

[0065] The measured results are shown in Figure 7. The group without magnetic iron oxide reached its peak cumulative gas production after 13 days of reaction in the organic wastewater treatment system, with a total gas production of approximately 302 L. In contrast, the group with magnetic iron oxide reached its peak after only 8 days of reaction in the organic wastewater treatment system, with a total gas production of approximately 331 L. Compared to the group without magnetic iron oxide, the group with magnetic iron oxide showed improvements in both yield and productivity. This indicates that magnetic iron oxide can simultaneously act as an abrasive and an interspecific electron transfer promoter in the wastewater treatment system. The addition of magnetic iron oxide can increase methane production by at least 10% and increase productivity by at least 1.8 times.

[0066] In summary, according to the embodiments disclosed herein, an organic wastewater treatment method is provided that can simultaneously improve sludge pretreatment efficiency and methane yield. By adding magnetic oxide feedstock and combining it with wastewater treatment process scheduling, the oxide feedstock can act as an ultrasonic abrasive and a biochemical metabolic catalyst at different stages of wastewater treatment, synergistically enhancing the existing ultrasonic sludge hydrolysis technology and the subsequent anaerobic biological metabolic organic matter conversion function. This achieves the effect of simultaneously improving sludge pretreatment efficiency and methane yield, and can treat organic wastewater in a more energy-efficient and effective manner.

[0067] While the embodiments and advantages of this disclosure have been presented above, it should be understood that anyone skilled in the art can make modifications, substitutions, and refinements without departing from the spirit and scope of this disclosure. Furthermore, each claim constitutes an individual embodiment, and the scope of protection of this disclosure also includes combinations of the various claims and embodiments. The scope of protection of this disclosure shall be determined by the appended claims.

[0068] 1S: Organic wastewater treatment system 1M: Organic Wastewater Treatment Methods 10: Feeding Unit 20: Magnetic oxide material supply unit 30: Ultrasonic Processing Unit 40: Separation Unit 50: Anaerobic biological treatment unit HS: Hydrolyzed sludge L: Connector L1: Connector L2: Connector L3: Connector MO: Magnetic oxide material source MT: Methane O1: First organic liquid O2: Second organic liquid P0: Magnetic nanoparticles P1: First magnetic nanoparticle P2: Second magnetic nanoparticle S1: Steps S2: Steps S3: Steps S4: Steps WT: Organic wastewater

Claims

1. A method for treating organic wastewater, comprising the following steps: (a) providing a magnetic oxide source and mixing it with organic wastewater to form a first organic liquid comprising the magnetic oxide source and the organic wastewater; (b) subjecting the first organic liquid to ultrasonic treatment to produce a second organic liquid comprising magnetic nanoparticles of different sizes and a hydrolyzed sludge; (c) subjecting the second organic liquid to a separation treatment, separating the magnetic nanoparticles of different sizes into a first magnetic nanoparticle and a second magnetic nanoparticle according to their size, wherein the first magnetic nanoparticle is recirculated to mix with the first organic liquid to continuously subject the first organic liquid to ultrasonic treatment; and (d) subjecting the hydrolyzed sludge to anaerobic biological treatment with the second magnetic nanoparticle to convert it into methane, wherein... The magnetic oxide source, the first magnetic nanoparticle, and the second magnetic nanoparticle comprise at least magnetic iron oxide. The size of the first magnetic nanoparticle is between 200 nanometers and 5 micrometers, and the size of the second magnetic nanoparticle is between 20 nanometers and 200 nanometers.

2. The organic wastewater treatment method as described in claim 1, wherein the size of the magnetic oxide material source is between 200 nanometers and 5 micrometers.

3. The organic wastewater treatment method as described in claim 1, wherein the organic wastewater includes food industry wastewater, manufacturing wastewater, petrochemical industry wastewater, agricultural wastewater, livestock industry wastewater, or a combination thereof.

4. The organic wastewater treatment method as described in claim 1, wherein in step (a), the weight-volume percentage (w / v) of the magnetic oxide source to the organic wastewater is between 0.01% and 1%.

5. The organic wastewater treatment method as claimed in claim 1, wherein in step (b), the output power of the ultrasonic treatment is between 300 watts and 1200 watts, and the frequency is between 20 kHz and 100 kHz.

6. The organic wastewater treatment method as described in claim 5, wherein the ultrasonic treatment is performed for a period of 1 minute to 20 minutes.

7. The organic wastewater treatment method as claimed in claim 1, wherein in step (d), the anaerobic biological treatment is carried out under conditions of a temperature between 25°C and 45°C and a pH between 6.8 and 7.

2.

8. The organic wastewater treatment method as claimed in claim 1, wherein in step (d), the anaerobic biological treatment includes the use of hydrolytic bacteria, acid-producing bacteria, methanogenic bacteria, or a combination thereof.

9. The organic wastewater treatment method as described in claim 1, comprising performing steps (b) to (d) 5 to 20 times consecutively.

10. The organic wastewater treatment method as described in claim 1, wherein the separation process is a gravity sedimentation separation process or a magnetic adsorption separation process.

11. The method for treating organic wastewater as claimed in claim 1, wherein the magnetic iron oxide comprises iron(III) oxide (Fe3O4), ferrous oxide (FeO), ferric oxide (Fe2O3), or a combination thereof.

12. An organic wastewater treatment system, comprising: The system comprises: a feeding unit providing organic wastewater; a magnetic oxide feed source unit connected to the feeding unit and providing a magnetic oxide feed source for mixing with the organic wastewater to form a first organic liquid containing the magnetic oxide feed source and the organic wastewater; an ultrasonic treatment unit connected to the feeding unit and ultrasonically treating the first organic liquid to produce a second organic liquid containing magnetic nanoparticles of different sizes and hydrolyzed sludge; a separation unit connected to the ultrasonic treatment unit and separating the magnetic nanoparticles of different sizes into a first magnetic nanoparticle and a second magnetic nanoparticle, wherein the first magnetic nanoparticle is returned to the upstream of the ultrasonic treatment unit to mix with the first organic liquid for continuous ultrasonic treatment of the first organic liquid; and an anaerobic biological treatment unit connected to the separation unit, wherein the second magnetic nanoparticle is used in the anaerobic biological treatment unit to anaerobically treat the hydrolyzed sludge to convert it into methane. The magnetic oxide material source, the first magnetic nanoparticle, and the second magnetic nanoparticle include at least magnetic iron oxide. The size of the first magnetic nanoparticle is between 200 nanometers and 5 micrometers, and the size of the second magnetic nanoparticle is between 20 nanometers and 200 nanometers.

13. The organic wastewater treatment system as claimed in claim 12, wherein the ultrasonic treatment unit is located upstream of the separation unit, and the separation unit has a first connector connected downstream of the ultrasonic treatment unit.

14. The organic wastewater treatment system as claimed in claim 12, wherein the separation unit further comprises a second connector connected upstream of the ultrasonic treatment unit and a third connector connected upstream of the anaerobic biological treatment unit.

15. The organic wastewater treatment system as described in claim 12, wherein the organic wastewater includes food industry wastewater, manufacturing wastewater, petrochemical industry wastewater, agricultural wastewater, livestock industry wastewater, or a combination thereof.

16. The organic wastewater treatment system as described in claim 12, wherein the size of the magnetic oxide source is between 200 nanometers and 5 micrometers.

17. The organic wastewater treatment system as claimed in claim 12, wherein the output power of the ultrasonic treatment is between 300 watts and 1200 watts, and the frequency is between 20 kHz and 100 kHz.

18. The organic wastewater treatment system as claimed in claim 12, wherein the anaerobic biological treatment is carried out at a temperature between 25°C and 45°C and a pH between 6.8 and 7.

2.

19. The organic wastewater treatment system as claimed in claim 12, wherein the anaerobic biological treatment unit includes an anaerobic fermentation tank, and the anaerobic fermentation tank includes hydrolytic bacteria, acid-producing bacteria, methanogenic bacteria, or a combination thereof.

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