A cyanobacteria harmless resourceful treatment process

Abstract

This invention relates to the field of cyanobacteria treatment technology, and more particularly to a harmless and resource-based treatment process for cyanobacteria, comprising the following specific steps: S1, harvesting and pretreatment: cyanobacteria in the water are collected, crushed, and transported to a pretreatment tank for enzymatic pretreatment; S2, flocculation, sedimentation, and dewatering: flocculant is added to the cyanobacteria-rich water in the pretreatment tank, and the water is pumped to a dewatering tank for pressure filtration and dewatering to form a slurry of cyanobacteria; S3, anaerobic fermentation: fermentation is carried out in a constant-temperature anaerobic fermentation tank, where anaerobic microorganisms decompose the organic matter in the cyanobacteria into biogas, and the remaining algal residue is discharged into a composting tank through pipes; S4, aerobic composting: high-temperature rapid composting utilizes microorganisms to degrade residual toxins. This invention employs a biological treatment process of anaerobic fermentation followed by aerobic composting to treat cyanobacteria, using microbial fermentation for resource-based treatment of cyanobacteria, resulting in low production costs, reliable removal of algal toxins and heavy metals, reduced byproducts, and improved resource utilization.

Description

Technical Field

[0001] This invention relates to the field of cyanobacteria treatment technology, and in particular to a process for the harmless and resource-based treatment of cyanobacteria. Background Technology

[0002] Cyanobacteria are prokaryotes, also known as blue-green algae or cyanobacteria. Most cyanobacteria have a gelatinous coating around their cell walls, hence the name "slime algae." In some nutrient-rich waters, certain cyanobacteria often proliferate in large numbers during the summer, forming a layer of blue-green, foul-smelling foam on the surface, known as an algal bloom. Large-scale cyanobacterial blooms are called "green tides" (corresponding to red tides in the ocean). Green tides cause water quality deterioration, and in severe cases, deplete oxygen in the water, leading to fish deaths. Even more seriously, some species of cyanobacteria (such as Microcystis) produce microcystin toxins, thus requiring regular cyanobacterial cleanup.

[0003] Cyanobacteria can be used as a resource in several ways, such as: Safe fertilizer: Detoxified cyanobacteria compost can be used for flowers or trees, preventing heavy metals from entering the food chain. Energy conversion: Dehydrated cyanobacteria undergo anaerobic fermentation to produce biogas, but the decomposition products of toxins during fermentation need to be monitored. Fertilizer: The rich organic matter, nitrogen, phosphorus, and potassium elements in cyanobacteria can be used to make compost or biogas fertilizer, but the problems of algal toxins and heavy metal residues need to be addressed. Energy conversion: Through anaerobic fermentation, biogas can be produced. An annual production of 5,000 tons (dry algae) of cyanobacteria from Dianchi Lake can produce 2 million cubic meters of biogas, enough to supply 10,000 households. Extraction of bioactive substances: Phycobiliproteins (natural pigments), polysaccharides, etc., can be extracted for use in food, cosmetics, or biopesticides. Feed ingredient: Cyanobacteria have a high protein content and can be used as a feed additive, but detoxification treatment is required.

[0004] However, the dehydration and detoxification of cyanobacteria are costly: cyanobacteria contain 97% water, making dehydration expensive, and the removal of algal toxins is difficult: microcystin toxins are heat-resistant and difficult to decompose, requiring activated carbon adsorption or chemical treatment. Furthermore, there are heavy metal residues: cyanobacterial sheaths easily accumulate heavy metals, and direct application as fertilizer may pollute the soil and crops.

[0005] Existing methods for the resource recovery of cyanobacteria are costly and complex, and generally only involve harvesting and disposal. Due to cost constraints, resource utilization is not possible. Furthermore, the removal of algal toxins and heavy metals is difficult, which affects the resource recovery of cyanobacteria. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing a harmless and resource-based treatment process for cyanobacteria.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A process for the harmless and resource-based treatment of cyanobacteria includes the following specific steps: S1. Salvage and pretreatment: Salvage boats or algae-water separation stations are used to collect cyanobacteria in the water. After preliminary crushing by crushing equipment, the algae are transported to the pretreatment tank for enzymatic pretreatment. Cellulase and pectinase are added to decompose the cell walls of cyanobacteria. S2. Flocculation, sedimentation and dehydration: Flocculant is evenly added to the cyanobacteria water in the pretreatment tank and stirred thoroughly to ensure that the flocculant and cyanobacteria are in full contact. The flocculant and cyanobacteria undergo a flocculation reaction to form larger flocs, which aggregate and settle at the bottom of the pretreatment tank. The flocculant is then pumped to the dehydration tank for further separation of algae and water. At the same time, the water is dehydrated by pressure filtration to form slurry-like cyanobacteria. S3. Anaerobic fermentation: The screw conveyor at the bottom of the dehydration tank transports the slurry-like cyanobacteria to the fermentation tank, and at the same time, the cultured inoculum is added. Fermentation takes place in the constant temperature anaerobic fermentation tank. Anaerobic microorganisms decompose the organic matter in the cyanobacteria into biogas. The biogas is discharged and collected through the exhaust pipe, and the remaining algal residue is discharged into the composting pit through the pipe. S4, aerobic composting, high-temperature rapid composting, utilizes microorganisms to degrade residual toxins, monitors pH, temperature, and volatile fatty acids in real time, and adjusts process parameters in a timely manner to avoid acidification or ammonia inhibition.

[0008] Preferably, in step S2, the appropriate type and dosage of flocculant are determined based on the specific conditions of the water body, such as cyanobacterial concentration, pH value, and water temperature; the flocculant is selected from polyaluminum chloride, polyacrylamide, or extracellular polysaccharide.

[0009] Preferably, the fermentation conditions in step S3 are as follows: Temperature: Medium-temperature fermentation at 35℃, fermentation cycle 30-45 days; or high-temperature fermentation at 50-55℃, cycle 15-25 days; pH value: The suitable pH range for methanogens is 6.8–7.5; Inoculum: Generally, it is anaerobic sludge. Inoculation with high-efficiency anaerobic sludge can accelerate fermentation start-up and shorten the adaptation period.

[0010] Preferably, in step S4, the aerobic composting step includes: a. High-temperature stage of primary fermentation: Aerobic microorganisms rapidly decompose organic matter, and the temperature rises to 55-65℃; b. Post-fermentation: The remaining organic matter is further decomposed, the temperature drops, and the pile stabilizes; c. Post-processing: Screening removes impurities to obtain uniform, well-rotted compost; d. Storage: Prevent secondary pollution and maintain fertilizer effectiveness.

[0011] Preferably, the pretreatment tank is provided in multiple sets, and the pretreatment tank is connected to multiple sets of dehydration tanks, and each dehydration tank is connected to at least one fermentation tank.

[0012] Preferably, the dehydration tank includes a clear liquid tank, a pressure bar, and a sedimentation tank. The sedimentation tank is connected to the discharge pump and a discharge valve is provided between them. A recovery valve is connected to one side of the clear liquid tank. The recovery valve is connected to a circulating water tank. A flushing water pipe is connected to the outlet of the circulating water tank. A pressure pump is provided on the flushing water pipe.

[0013] Preferably, the bottom of the pretreatment tank is inclined, the discharge pump is connected to the lower side of the pretreatment tank, the side wall of the pretreatment tank is provided with a rinsing nozzle, and the rinsing water pipe is connected to the rinsing nozzle.

[0014] Preferably, a hydraulic cylinder is provided on the outside of the clear liquid tank, a connecting frame is provided between the hydraulic cylinder and the top of the pressure rod, an adjusting gear is rotatably provided on the top of the clear liquid tank, an external spline is provided on the pressure rod, an internal spline corresponding to the external spline is provided in the middle of the adjusting gear, and a driving device is provided on one side of the adjusting gear.

[0015] Preferably, the lower end of the pressure rod extends to the inside of the clear liquid tank, the lower end of the pressure rod is provided with a pressure plate, the lower side of the pressure plate is provided with a cylindrical filter screen, the lower end of the cylindrical filter screen is provided with a fixing ring, and the fixing ring is disposed between the clear liquid tank and the sedimentation tank; the screw conveyor includes a conveying pipe, a screw rod and a screw motor, and the conveying pipe is connected to the bottom of the sedimentation tank.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention uses a biological treatment process of anaerobic fermentation followed by aerobic composting to treat cyanobacteria. It uses microbial fermentation to treat cyanobacteria for resource recovery, resulting in low production costs, reliable removal of algal toxins and heavy metals, reduced by-products, and improved resource utilization. 2. The present invention has a cylindrical filter screen installed in the dehydration tank, which works with the pressure plate to squeeze and improve the dehydration efficiency of blue-green algae. At the same time, during the lifting and rotation of the pressure plate, the cylindrical filter screen is driven to wash in the water, achieving self-cleaning and reducing the cost of use and maintenance. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the process of harmless and resource-based treatment of cyanobacteria proposed in this invention. Figure 2 This is a three-dimensional assembly structure diagram of the equipment involved in the harmless and resource-based treatment process for cyanobacteria proposed in this invention; Figure 3 This is a top view schematic diagram of the equipment involved in the harmless and resource-based treatment process for cyanobacteria proposed in this invention; Figure 4 This is a three-dimensional structural diagram of the dehydration tank involved in the harmless and resource-based treatment process for cyanobacteria proposed in this invention. Figure 5This is a schematic cross-sectional view of the dehydration tank involved in the harmless and resource-based treatment process for cyanobacteria proposed in this invention.

[0018] In the diagram: 1. Pretreatment tank; 11. Flushing nozzle; 12. Discharge pump; 2. Discharge valve; 3. Dehydration tank; 31. Clarified liquid tank; 32. Hydraulic cylinder; 33. Pressure rod; 331. Pressure plate; 34. Drive device; 35. Adjusting gear plate; 36. Sedimentation tank; 37. Screw conveyor; 371. Conveying pipe; 372. Screw rod; 38. Cylindrical filter screen; 4. Fermentation tank; 41. Exhaust pipe; 5. Composting tank; 51. Slag discharge valve; 6. Recovery valve; 7. Circulating water storage tank; 8. Flushing water pipe. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Reference Figure 1-5 A process for harmless and resource-based treatment of cyanobacteria, involving equipment including multiple sets of pretreatment tanks 1, which work alternately to meet the working time of the equipment. Each pretreatment tank 1 is connected to multiple sets of dehydration tanks 3 to provide working time for sedimentation and pressure filtration dehydration. Each dehydration tank 3 is connected to at least one fermentation tank 4, which work alternately to meet the fermentation conditions and avoid frequent opening and closing, which would affect the fermentation quality. The specific steps include: S1. Salvage and pretreatment: Use a salvage boat or algae-water separation station to collect blue-green algae in the water. The algae are then initially crushed by a crushing device. A high-pressure homogenizer is selected for the crushing device. The high-pressure fluid is used to generate cavitation effect through a narrow valve to break the cell wall, which is suitable for subsequent enzymatic hydrolysis and fermentation processes. The crushed cyanobacteria wastewater is transported to pretreatment tank 1 for enzymatic pretreatment, where cellulase and pectinase are added to decompose the cyanobacteria cell walls. S2, flocculation and sedimentation and dehydration, enzymatic pretreatment destroys the cell wall of cyanobacteria and releases intracellular substances, followed by flocculation treatment to aggregate and remove cyanobacteria and their decomposition products, and initially remove some algal toxins and heavy metals. Based on the specific conditions of the water body, such as the concentration of cyanobacteria, pH value, and water temperature, determine the appropriate type and dosage of flocculant; uniformly add flocculant to the cyanobacteria-laden water in pretreatment tank 1 and stir thoroughly to ensure that the flocculant and cyanobacteria are in full contact; the flocculant can be polyaluminum chloride, polyacrylamide, or extracellular polysaccharide. Polyaluminum chloride (PAC) is a commonly used inorganic polymeric flocculant with advantages such as good flocculation effect and fast sedimentation speed. In the treatment of cyanobacteria, PAC can effectively destroy the colloidal stability of cyanobacteria and promote their flocculation and sedimentation.

[0021] Polyacrylamide (PAM) is a synthetic polymeric flocculant, sometimes also used as a coagulant aid. PAM can be used in combination with inorganic flocculants such as polyacrylamide (PAC) to improve flocculation.

[0022] In response to the unique properties of cyanobacteria, composite flocculants can be developed, such as those containing strontium periodate, polyaluminum chloride, and chitosan. These composite flocculants can target the cellular structure of cyanobacteria, thereby improving flocculation efficiency.

[0023] In addition, extracellular polysaccharides can replace chemical flocculants in water treatment, avoiding secondary pollution.

[0024] The flocculant reacts with the cyanobacteria to form large flocs, which aggregate and settle at the bottom of the pretreatment tank 1. The flocs are then transported to the dewatering tank 3 by the discharge pump 12 for further separation of algae and water. At the same time, the algae are dewatered by pressure filtration, which initially dewaters the cyanobacteria with a water content of 98% to 99% to a water content of 80% to 90%, forming slurry-like cyanobacteria. S3. Anaerobic fermentation: The bottom screw conveyor 37 of the dehydration tank 3 transports the slurry-like cyanobacteria to the fermentation tank 4, while simultaneously adding the cultured inoculum, typically anaerobic sludge. The slurry-like cyanobacteria and anaerobic sludge are mixed and fermented in the constant-temperature anaerobic fermentation tank 4. Anaerobic microorganisms decompose the organic matter in the cyanobacteria into biogas, mainly composed of methane and carbon dioxide, with a methane content reaching 64.91%. Simultaneously, some toxins are decomposed. Highly efficient degrading bacteria, such as *Sphingosine Monoclonalella*, are screened. Under anaerobic conditions, *Rhodopseudomonas palustris* can achieve a degradation rate of 78.7% for microcystin toxins. Biogas is discharged and collected through exhaust pipe 41 for easy reuse, and the remaining algal residue is discharged into composting pit 5 through pipe. Anaerobic fermentation conditions: Temperature: Medium-temperature fermentation at around 35℃ has a higher gas production efficiency and a fermentation cycle of 30-45 days; if high-temperature fermentation at 50-55℃ is used, the microbial activity is enhanced and the cycle can be shortened to 15-25 days, but the requirements for the temperature resistance of the equipment are higher. pH value: The suitable pH range for methanogens is 6.8 to 7.5. Deviation from this range may lead to fermentation inhibition and prolong the cycle. Inoculum: Generally, it is anaerobic sludge. Inoculation with high-efficiency anaerobic sludge can accelerate fermentation start-up and shorten the adaptation period. The inoculation ratio is usually 1:6 to 1:8 (substrate to sludge mass ratio).

[0025] Cyanobacteria species and concentrations: Different cyanobacteria have significantly different organic matter content and nitrogen-phosphorus ratios, and high-concentration cyanobacteria require a longer time to degrade.

[0026] Anaerobic fermentation example: Fermentation of cyanobacteria and pig manure: Under the conditions of an inoculation ratio of 2:1, pH 7.9, and a fermentation broth concentration of 2.9%, the fermentation cycle is about 15 days, and the methane content can reach more than 60%.

[0027] Cyanobacteria and straw mixed fermentation: straw, cyanobacteria and inoculated sludge are fermented in a ratio of 2:8:1, with a cycle of about 52 days and a methane content of 72.24%.

[0028] Pressurized concentrated cyanobacteria fermentation: Under conditions of 35℃ and a sludge inoculation ratio of 1:6, the anaerobic fermentation cycle of concentrated algae is about 30 days, and the algal toxin removal rate reaches more than 99%.

[0029] S4, Aerobic Composting: High-temperature rapid composting is carried out in composting pit 5, utilizing microorganisms to degrade residual toxins. Under aerobic conditions, organic waste undergoes oxidation-reduction and biosynthesis through the life activities of aerobic bacteria. Aerobic microorganisms oxidize some of the absorbed organic matter into simple inorganic matter, while releasing energy needed for microbial growth and activity. The other part of the organic matter is synthesized into new cytoplasm, enabling microorganisms to continuously grow and reproduce.

[0030] Aerobic composting steps include: a. High-temperature stage of primary fermentation: Aerobic microorganisms rapidly decompose organic matter, and the temperature rises to 55-65℃, lasting for several days to several weeks; b. Post-fermentation: The remaining organic matter is further decomposed, the temperature drops, and the pile stabilizes; c. Post-processing: Screening removes impurities to obtain uniform, well-rotted compost; d. Storage: Prevent secondary pollution and maintain fertilizer effectiveness.

[0031] Real-time monitoring of indicators such as pH, temperature, and volatile fatty acids (VFA) is conducted to adjust process parameters in a timely manner and avoid acidification or ammonia inhibition. Process parameters include oxygen supply, water content, carbon-nitrogen ratio, carbon-phosphorus ratio, pH value, and temperature.

[0032] Oxygen supply: Insufficient oxygen will cause a large number of microorganisms to die and slow down the decomposition rate; too much cold air will lower the temperature, which is not conducive to the oxidation and decomposition process of heat-resistant bacteria. Therefore, the oxygen supply should be appropriate.

[0033] Moisture content: Too little moisture hinders the reproduction of microorganisms and slows down the decomposition process; too much moisture will cause insufficient oxygen supply to organic matter, thus turning it into an anaerobic state. Excessive moisture evaporation will take away most of the heat, preventing the achievement of a good high-temperature stage. Generally, a moisture content of 50%-60% is more suitable.

[0034] The carbon-to-nitrogen ratio (C / N) varies with the rate at which organic matter is decomposed by microorganisms; a ratio that is too high or too low will not yield ideal results. Cyanobacteria initially have a low C / N ratio of approximately 4-6 and a high water content of approximately 90%, making them unsuitable for direct aerobic composting. They require the addition of large amounts of straw and other materials for mixing and composting. A suitable C / N ratio is 25:1 to 30:1.

[0035] Carbon-to-phosphorus ratio: Phosphorus deficiency leads to reduced composting efficiency.

[0036] pH value: Microorganisms are most active in degrading carbon, nitrogen, phosphorus, etc. when the pH value is neutral or weakly alkaline; the suitable pH range for bacterial growth is 6.0 to 7.5, and the suitable pH range for actinomycete growth is 5.5 to 8.0.

[0037] Temperature: Temperature is a crucial factor affecting microbial activity and composting processes. Changes in the temperature of the compost pile reflect changes in the activity of microorganisms within it. Too low a temperature leads to slow decomposition of organic matter, while too high a temperature inhibits or kills some beneficial microorganisms. The optimal composting temperature is 50–60℃, within which pathogens are killed and microbial activity is maintained.

[0038] Aerobic composting example: Selenium-enriched cyanobacteria aerobic composting experiment: Cyanobacteria, bacterial residue, and rice husks were mixed in a ratio of 1:10:1, and the moisture content was adjusted to about 60%. The final carbon-nitrogen ratio was about 22. The mixture was then placed into a 30L self-made composting bucket. Aeration was carried out every 3 days, and the pile was turned over every 10 days. Each time the pile was turned over, an appropriate amount of water was added depending on the moisture content of the pile. The composting time was 48 days.

[0039] Dehydration and aerobic composting experiment of cyanobacteria blooms: After dehydration, cyanobacteria, sawdust and decomposed sludge were composted in a 1:2:1 ratio in a pilot test. The dehydrated cyanobacteria reached maturity after one month. During the composting process, the content of algal toxins was significantly reduced, ensuring the safety of cyanobacteria compost for agricultural use.

[0040] Aerobic composting of cyanobacteria and biochar: Cyanobacteria and biochar are mixed to obtain a cyanobacteria-biochar mixture, which is then aerobically composted in a constant temperature and humidity incubator. The moisture content of the cyanobacteria-biochar mixture is 50%–80%, the pH is 8.0–9.5, and the C / N ratio is 18–30. The temperature for aerobic composting is set as follows: a heating process from 30℃ to 60℃, a sustained high temperature process at 60℃, a cooling process from 60℃ to 20℃, and a cooling and stabilization process at 20℃. The total aerobic composting time is 30–45 days, preferably 35–41 days. Biochar is porous with a large specific surface area, exhibiting excellent water and fertilizer retention properties. It also has an adsorption and fixation effect on nitrogen, which can regulate the C / N ratio, moisture content, free space, and compost nutrients of the material, ensuring rapid and efficient composting, reducing the loss of ammonium nitrogen and total nitrogen, reducing the content of cyanobacterial toxins, and improving the seed germination index.

[0041] like Figure 2 As shown, the bottom of the pretreatment tank 1 is inclined to facilitate sedimentation and flocculation. The discharge pump 12 is connected to the lower side of the pretreatment tank 1. The side wall of the pretreatment tank 1 is equipped with a flushing nozzle 11. The water is agitated by the water flow to improve the mixing uniformity and flush the pretreatment tank 1 to prevent the accumulation of blue-green algae. like Figure 4 , Figure 5 As shown, the dehydration tank 3 includes a clear liquid tank 31, a pressure rod 33, and a sedimentation tank 36. The clear liquid tank 31 and the sedimentation tank 36 are connected by bolts and assembled into a tank body. The sedimentation tank 36 is connected to the discharge pump 12 and is provided with a discharge valve 2 to control the water in the pretreatment tank 1 to flow into the sedimentation tank 36 for sedimentation and separation. The discharge valve 2 is equipped with a flushing connection port. When the pipeline is blocked, it can be repaired through the flushing connection port, or a high-pressure water pipe can be connected to flush the blockage through the high-pressure water flow. A recovery valve 6 is connected to one side of the supernatant tank 31. After the algae and water are separated, the supernatant flows out through the recovery valve 6 for recycling. The recovery valve 6 is connected to a circulating water storage tank 7. A filtration device is installed in the circulating water storage tank 7. The circulating water storage tank 7 is used to store the supernatant filtered from the algae and water for further treatment, filtration or disinfection, and removal of blue-green algae and other pollutants. The outlet of the circulating water storage tank 7 is connected to a flushing water pipe 8. A pressure pump is installed on the flushing water pipe 8. The flushing water pipe 8 is connected to the flushing nozzle 11 to spray out the recovered supernatant to clean the pretreatment tank 1 and reduce water consumption. A hydraulic cylinder 32 is provided on the outside of the clear liquid tank 31. A connecting frame is provided between the hydraulic cylinder 32 and the top of the pressure rod 33. The hydraulic cylinder 32 controls the pressure rod 33 to move up and down. An adjusting gear 35 is rotatably provided on the top of the clear liquid tank 31. An external spline is provided on the pressure rod 33. An internal spline corresponding to the external spline is provided in the middle of the adjusting gear 35. A driving device 34 is provided on one side of the adjusting gear 35. The driving device 34 includes a driving motor and a driving gear, which is used to control the rotation of the adjusting gear 35, thereby driving the pressure rod 33 to rotate. The lower end of the pressure rod 33 extends to the inside of the clear liquid tank 31. The lower end of the pressure rod 33 is provided with a pressure plate 331. The pressure rod 33 drives the pressure plate 331 to rotate or move up and down. A cylindrical filter screen 38 is provided on the lower side of the pressure plate 331. A fixing ring is provided at the lower end of the cylindrical filter screen 38. The fixing ring is set between the clear liquid tank 31 and the sedimentation tank 36. The opening of the cylindrical filter screen 38 faces downward, covering the deposited blue algae. The pressure rod 33 is pressed down or rotated, thereby driving the pressure plate 331 to move, squeezing the blue algae in the cylindrical filter screen 38, filtering out the wastewater, and pressing the blue algae into a slurry to control the water content. The screw conveyor 37 includes a conveying pipe 371, a screw rod 372 and a screw motor. The conveying pipe 371 is connected to the bottom of the sedimentation tank 36 and is used to send slurry-like cyanobacteria to the fermentation tank 4.

[0042] A slag discharge valve 51 is provided between the fermentation tank 4 and the composting tank 5 to control the flow of algae residue between the fermentation tank 4 and the composting tank 5.

[0043] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0044] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0045] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

Claims

1. A process for the harmless and resource-based treatment of cyanobacteria, characterized in that, Including specific steps: S1. Salvage and pretreatment: Salvage boats or algae-water separation stations are used to collect cyanobacteria in the water. After preliminary crushing by crushing equipment, the algae are transported to the pretreatment tank (1) for enzymatic pretreatment. Cellulase and pectinase are added to decompose the cell walls of cyanobacteria. S2, flocculation sedimentation and dehydration: Flocculant is evenly added to the cyanobacterial water in the pretreatment tank (1) and stirred thoroughly to ensure that the flocculant and cyanobacterial are in full contact; the flocculant and cyanobacterial react to form flocs, which aggregate and settle at the bottom of the pretreatment tank (1) and are transported to the dehydration tank (3) by the discharge pump (12) for further separation of algae water. At the same time, the algae water is dehydrated by pressure filtration to form slurry cyanobacterial. The dehydration tank (3) includes a clear liquid tank (31), a pressure rod (33) and a sedimentation tank (36). The sedimentation tank (36) is connected to the discharge pump (12) and a discharge valve (2) is provided between them. The clear liquid tank (31) is connected to a recovery valve (6) on one side, the recovery valve (6) is connected to a circulating water tank (7), the outlet of the circulating water tank (7) is connected to a flushing water pipe (8), and a pressure pump is provided on the flushing water pipe (8). A hydraulic cylinder (32) is provided on the outside of the clear liquid tank (31). A connecting frame is provided between the hydraulic cylinder (32) and the top of the pressure rod (33). An adjusting gear plate (35) is rotatably provided on the top of the clear liquid tank (31). An external spline is provided on the pressure rod (33). An internal spline corresponding to the external spline is provided in the middle of the adjusting gear plate (35). A driving device (34) is provided on one side of the adjusting gear plate (35). The lower end of the pressure rod (33) extends to the inside of the clear liquid tank (31). A pressure plate (331) is provided at the lower end of the pressure rod (33). A cylindrical filter screen (38) is provided on the lower side of the pressure plate (331). A fixing ring is provided at the lower end of the cylindrical filter screen (38). The fixing ring is located between the clear liquid tank (31) and the sedimentation tank (36). S3. Anaerobic fermentation: The bottom screw conveyor (37) of the dehydration tank (3) transports the slurry cyanobacteria to the fermentation tank (4) and simultaneously puts in the cultured inoculum. Fermentation takes place in the constant temperature anaerobic fermentation tank (4). Anaerobic microorganisms decompose the organic matter in the cyanobacteria into biogas. The biogas is discharged and collected through the exhaust pipe (41). The remaining algal residue is discharged into the composting pond (5) through the pipe. The screw conveyor (37) includes a conveying pipe (371), a screw rod (372) and a screw motor, wherein the conveying pipe (371) is connected to the bottom of the sedimentation tank (36); S4, aerobic composting, high-temperature rapid composting, utilizes microorganisms to degrade residual toxins, monitors pH, temperature, and volatile fatty acids in real time, and adjusts process parameters in a timely manner to avoid acidification or ammonia inhibition.

2. The process for harmless and resource-based treatment of cyanobacteria according to claim 1, characterized in that, In step S2, the appropriate type and dosage of flocculant are determined according to the specific conditions of the water body; the flocculant is selected from polyaluminum chloride, polyacrylamide, or extracellular polysaccharide.

3. The process for harmless and resource-based treatment of cyanobacteria according to claim 1, characterized in that, Fermentation conditions in step S3: Temperature: Medium-temperature fermentation at 35℃, fermentation cycle 30-45 days; or high-temperature fermentation at 50-55℃, cycle 15-25 days; pH value: range 6.8 to 7.5; Inoculum: Anaerobic sludge.

4. The process for harmless and resource-based treatment of cyanobacteria according to claim 1, characterized in that, In step S4, the aerobic composting step includes: a. High-temperature stage of primary fermentation: Aerobic microorganisms rapidly decompose organic matter, and the temperature rises to 55-65℃; b. Post-fermentation: The remaining organic matter is further decomposed, the temperature drops, and the pile stabilizes; c. Post-processing: Screening removes impurities to obtain uniform, well-rotted compost; d. Storage: Prevent secondary pollution and maintain fertilizer effectiveness.

5. The process for harmless and resource-based treatment of cyanobacteria according to claim 1, characterized in that, The pretreatment tank (1) is provided with multiple sets, and the pretreatment tank (1) is connected to multiple sets of dehydration tanks (3). Each dehydration tank (3) is connected to at least one fermentation tank (4).

6. The process for harmless and resource-based treatment of cyanobacteria according to claim 1, characterized in that, The pretreatment tank (1) is inclined at the bottom, the discharge pump (12) is connected to the lower side of the pretreatment tank (1), the side wall of the pretreatment tank (1) is provided with a rinsing nozzle (11), and the rinsing water pipe (8) is connected to the rinsing nozzle (11).

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