A method for cleaning and purifying a sewer

Abstract

The application relates to the technical field of sewage treatment, and discloses a method for cleaning and purifying a sewer, which comprises the following steps: S1, sediment detection and high-pressure flushing; S2, composite alkaline catalyst adding and mixing; S3, reaction in a sewage pool; S4, solid-liquid separation; and S5, sewage deep purification. The method first detects the organic matter and inorganic matter contents of the sediment by the weight method, the core function of which is to provide a quantitative basis for subsequent composite alkaline catalyst adding, to avoid the defects of blind adding in the traditional technology, and to ensure that the medicament dosage and the pollutant load can be matched. The high-pressure flushing can completely strip the stubborn sediments on the inner wall, the bottom and the corner of the sewer, meanwhile, the 45 DEG-60 DEG spray head angle can avoid flushing dead angles and reduce the residual pollutants in the pipeline.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically a method for dredging and purifying drainage pipes and channels. Background Technology

[0002] As the core infrastructure of urban drainage systems, drainage pipes and channels bear the crucial functions of rainwater and sewage transportation, flood control, and drainage. During long-term operation, the inner walls of these pipes and channels are prone to accumulating silt, a mixture of organic matter (such as cellulose and fatty substances) and inorganic matter (such as mud and gravel) carried by domestic sewage and industrial wastewater. If the silt is not cleaned and purified in a timely or thorough manner, it will not only lead to a reduction in pipe cross-section and a decrease in flow velocity, causing pipe blockage and waterlogging, but also produce foul-smelling gases due to anaerobic fermentation of the silt, polluting the surrounding air environment. Furthermore, during rainfall or flushing, the silt will enter natural water bodies with sewage, causing eutrophication and water quality deterioration.

[0003] Therefore, it is necessary to dredge and purify the drainage pipes and channels. Summary of the Invention

[0004] To address the problems in the prior art, this invention provides a method for dredging and purifying drainage pipes and channels.

[0005] The technical solution adopted by this invention to solve its technical problem is: a method for dredging and purifying drainage pipes and channels, comprising the following steps:

[0006] S1: Sediment Detection and High-Pressure Flushing: Detect the organic and inorganic content of the drainage pipes and channels; then flush the sediment in the pipes and channels with a high-pressure water gun, and discharge the flushed wastewater into the sewage treatment pond;

[0007] S2: Addition and mixing of composite alkaline catalyst: Based on the sediment detection results in step S1, the composite alkaline catalyst is directly added to the wastewater in the wastewater treatment tank. The composite alkaline catalyst is composed of wood ash modified material and composite biological enzyme at a mass ratio of 1:8-10, which has the synergistic effect of providing an alkaline environment and targeted catalysis by biological enzymes, and can efficiently destroy the adhesion structure of suspended sediments in wastewater. The composite biological enzyme is composed of cellulase with an enzyme activity ≥1000U / g and lipase with an enzyme activity ≥800U / g at a mass ratio of 2-3:1. The wastewater treatment tank is stirred at a stirring rate of 70-100r / min, and stirring is continued.

[0008] S3: Reaction in the wastewater treatment tank: Maintain the natural ambient temperature in the wastewater treatment tank to allow the composite alkaline catalyst to react with the suspended sediments in the wastewater for 3-4 hours; During the reaction, monitor the pH value of the wastewater in the wastewater treatment tank every 30 minutes, randomly take the average pH value of three points, and maintain the pH value at 8.0-9.0. If the average value is lower than 8.0, add composite alkaline catalyst in increments of 0.1-0.2 g / L.

[0009] S4: Solid-liquid separation: After the reaction is complete, stop stirring and let the sewage stand in the sewage treatment tank for 50-60 minutes to allow the sedimentary solid sludge to settle to the bottom of the tank; the upper suspended sewage is filtered through a ceramic filter membrane, and the filtered solid sludge settled at the bottom of the tank and the upper pre-purified water are obtained.

[0010] S5: Deep wastewater purification: The pre-purified water from step S4 is passed sequentially through an activated carbon adsorption column and an ultraviolet disinfection device; the activated carbon particle size of the activated carbon adsorption column is 0.8-1mm and the contact time is 15-20min; the ultraviolet wavelength of the ultraviolet disinfection device is 254nm and the irradiation intensity is 12-15mW / cm², and the effluent meets the discharge standards.

[0011] As a further technical solution, the water pressure of the high-pressure water gun in step S1 is 500-600 bar, and the rinsing time is 35-40 min.

[0012] As a further technical solution, the preparation method of the composite alkaline catalyst in step S2 includes the following steps:

[0013] A1: Preparation of modified plant ash: Take plant ash, and obtain modified plant ash by high-temperature activation, organic acid modification, washing and drying; the high-temperature activation conditions are calcination at 800-900℃ for 2-3 hours, and cooling to room temperature and passing through a 100-mesh sieve.

[0014] A2: Preparation of composite bioenzyme: Cellulase and lipase are mixed in a mass ratio and activated by standing at 25-30℃ for 1 hour to obtain composite bioenzyme;

[0015] A3: Compound mixing: Add the wood ash modified product from step A1 and the composite bio-enzyme from step A2 to deionized water, mix for 30-45 min at a temperature of 30-35℃ and a stirring rate of 30-50 r / min, then dry at 60-70℃ for 2-3 h, and pulverize to a particle size of 100-200 mesh to obtain the composite alkaline catalyst.

[0016] As a further technical solution, the specific conditions for organic acid modification and cleaning and drying in step A1 are as follows: the activated wood ash is added to an organic acid solution with a mass concentration of 5-5.8%, the solid-liquid ratio of wood ash to organic acid solution is 1:7-10, and the reaction is carried out at 50-60℃ and a stirring rate of 40-50 r / min for 1.5-2 h; after the reaction is completed, the product is washed with deionized water until the pH value of the product is 7.5-8.5, and then vacuum dried at 80-90℃ and a vacuum degree of -0.08 to -0.09 MPa for 4-5 h to obtain the modified wood ash.

[0017] As a further technical solution, the organic acid solution is selected from citric acid and malic acid.

[0018] As a further technical solution, the ceramic filter membrane described in step S4 needs to be modified for hydrophilicity before filtration. Specifically, it is coated with a 2% polyvinyl alcohol solution with a coating thickness of 0.2mm ± 0.02mm. After coating, it is dried at room temperature for 20-25 minutes to reduce the filter membrane clogging rate.

[0019] As a further technical solution, the solid sludge obtained in step S4 is discharged through the sludge discharge valve at the bottom of the sewage tank. After discharge, 5-6% quicklime by mass is added for conditioning. The conditioning conditions are: stirring and mixing at room temperature of 20-25℃ for 18-20 minutes, with a stirring rate of 20-30 r / min, until the sludge moisture content drops to 60-70%. After conditioning, it is packed into sealed bags for external disposal.

[0020] As a further technical solution, the ceramic filter membrane in step S4 has a pore size of 0.1-0.2 μm and a filtration pressure of 0.1-0.2 MPa.

[0021] As a further technical solution, the activated carbon in the activated carbon adsorption column in step S5 is walnut shell-based activated carbon, which is activated at 900℃ and has a specific surface area ≥1000m² / g.

[0022] As a further technical solution, the number of lamps in the ultraviolet disinfection device in step S5 is configured according to the sewage discharge volume, with one 30W ultraviolet lamp configured for every 1m³ / h of sewage treated, and the ultraviolet irradiation dose ≥16mJ / cm².

[0023] The beneficial effects of this invention are as follows:

[0024] 1. This invention first uses a gravimetric method to detect the organic and inorganic content of the sediments. Its core function is to provide a quantitative basis for the subsequent addition of composite alkaline catalysts, avoiding the defects of blind dosing in traditional technology and ensuring that the dosage of the agent matches the pollutant load. High-pressure flushing can completely remove stubborn sediments from the inner wall, bottom and corners of the pipe, while the nozzle angle of 45°-60° can avoid the dead corners of flushing and reduce the residual pollutants in the pipeline.

[0025] 2. The composite alkaline catalyst introduced in this invention achieves dual synergistic effects of environmental regulation and targeted degradation. In the composite alkaline catalyst, the wood ash modified material, after high-temperature activation and organic acid modification, has a porous structure that can slowly release potassium salts, stably maintaining the pH of the wastewater treatment system at 8.0-9.0. The core mechanism of this alkaline environment is: on the one hand, it destroys the colloidal adhesion structure of suspended sediments, dispersing agglomerated sludge particles into fine particles with a diameter of <10μm, increasing the contact area between pollutants and the catalyst; on the other hand, it activates the activity of composite biological enzymes. The activity of cellulase is significantly improved at pH 8.0-9.0 compared to the neutral environment, and the activity of lipase is also improved, avoiding the deactivation problem caused by pH fluctuations in traditional single enzymes.

[0026] 3. The composite bioenzyme can target and degrade cellulose and fatty substances in the dispersed sediment separately. Its degradation mechanism involves enzyme molecules specifically binding to the substrate, breaking down large organic molecules into smaller molecules such as glucose and fatty acids, facilitating subsequent separation and adsorption. The synergistic effect between the modified wood ash and the composite bioenzyme is particularly crucial: the flocculating effect of wood ash provides more degradation sites for the bioenzyme, while the degradation effect of the bioenzyme converts the flocculated organic matter into easily treatable small molecules. The combination of these two factors significantly improves the COD removal rate, exceeding the COD removal effect of traditional single catalysts.

[0027] 4. In the solid-liquid separation stage of this invention, the ceramic filter membrane is modified with polyvinyl alcohol solution. The resulting hydrophilic membrane layer enhances the affinity between the membrane and water molecules through hydroxyl groups (-OH), reducing the solid-liquid interfacial tension and preventing suspended particles from adhering to and clogging the membrane surface. This anti-clogging mechanism maintains the filtration flux of the membrane at a high level, increasing the SS rejection rate. Combined with static sedimentation, gravity is used to achieve the initial separation of coarse sludge particles with a diameter >50μm from wastewater, further reducing the filtration load on the membrane and extending its service life. Simultaneously, quicklime is added to the solid sludge for conditioning. CaO reacts with water to generate Ca(OH)2, which absorbs moisture from the sludge and sterilizes it through an alkaline environment, achieving harmlessness and volume reduction of the sludge and avoiding secondary pollution caused by the indiscriminate disposal of sludge in traditional methods.

[0028] 5. In the deep purification stage, walnut shell-based activated carbon removes small-molecule organic matter (such as fatty acids and pigments) from the initially purified water through physical adsorption, with an adsorption capacity higher than that of ordinary coal-based activated carbon. Subsequent ultraviolet disinfection uses a wavelength of 254nm and an irradiation dose of ≥16mJ / cm². Because the activated carbon has removed organic matter and suspended solids, the ultraviolet light can directly act on the nucleic acids of microorganisms, destroying their genetic material and achieving sterilization. The synergistic effect of this stage is that activated carbon adsorption lays the foundation for ultraviolet disinfection, avoiding disinfection blind spots caused by obstruction, while ultraviolet disinfection completely inactivates microorganisms. This invention, through the synergistic technology of detection, synergistic catalysis, efficient separation, and deep purification throughout the entire process, specifically solves the problems of blind catalysis, inefficient catalysis, incomplete separation, and insufficient disinfection in existing technologies. The steps do not act independently but form an organic whole, ultimately ensuring that the treated wastewater meets discharge requirements. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0030] This invention provides a method for dredging and purifying drainage pipes and channels. This method solves the problem of dredging and purifying drainage pipes and channels through a synergistic process involving sediment detection, high-pressure flushing, catalytic reaction, solid-liquid separation, and deep purification. The method specifically includes the following steps:

[0031] Step S1: Sediment Detection and High-Pressure Flushing

[0032] Sediment Analysis: The organic and inorganic content of sediments in drainage pipes and channels was determined by gravimetric method. Specific procedures: A representative 100g sediment sample was taken and dried in a 105℃ oven to constant weight; the mass after drying, m1, was recorded. The dried sample was then transferred to a muffle furnace at 550℃ and ignited for 4 hours. After cooling to room temperature, the mass after ignition, m2, was recorded. The organic content was calculated using the formulas: Organic content = (m1 - m2) / 100 × 100%, Inorganic content = m2 / 100 × 100%.

[0033] High-pressure flushing: High-pressure water guns are used to flush the sediment in the pipes and channels. The water pressure of the high-pressure water gun is preferably 500-600 bar, and the flushing time is preferably 35-40 minutes. During flushing, the angle of the water gun nozzle is adjusted to 45°-60° to ensure that the sediment on the inner wall and bottom of the pipes and channels is fully removed. The wastewater generated by flushing is discharged into the wastewater treatment tank through the diversion pipe.

[0034] Step S2: Addition and mixing of the composite alkaline catalyst

[0035] The composite alkaline catalyst is composed of a mixture of modified wood ash and a composite bio-enzyme at a mass ratio of 1:8-10. The composite bio-enzyme is a mixture of cellulase with an activity ≥1000 U / g and lipase with an activity ≥800 U / g at a mass ratio of 2-3:1. Preferably, the cellulase activity is 1000-1500 U / g and the lipase activity is 800-1200 U / g, ensuring targeted degradation of cellulose and fatty organic matter in the sediment.

[0036] Preparation of composite alkaline catalysts:

[0037] Step A1: Preparation of modified wood ash: Take wood ash (total purity of K2CO3 and KOH ≥85%) produced by burning agricultural waste and first activate it at high temperature: Place the wood ash in a roasting furnace and roast at 800-900℃ for 2-3 hours, purging air during roasting (air flow rate 10-15L / min). After cooling to room temperature, pass it through a 100-mesh sieve to remove coarse particles; then perform organic acid modification: Add the high-temperature activated wood ash to a 5-5.8% (w / w) organic acid solution. The organic acid is selected from citric acid or malic acid, and the solid-liquid ratio of wood ash to organic acid solution is 1:7-10. The mixture is placed in a constant temperature water bath and reacted at 50-60℃ and a stirring rate of 40-50 r / min for 1.5-2 h. After the reaction is completed, the product is repeatedly washed with deionized water until the pH value is 7.5-8.5. Then the product is placed in a vacuum drying oven and vacuum dried at 80-90℃ and a vacuum degree of -0.08 to -0.09 MPa for 4-5 h to obtain wood ash modified product.

[0038] Step A2: Preparation of compound bio-enzyme: Weigh cellulase and lipase at a mass ratio of 2-3:1, place them in a constant temperature incubator, and activate them by standing for 1 hour at 25-30℃ and 50%-60% humidity to fully stimulate enzyme activity and obtain compound bio-enzyme.

[0039] Step A3: Compound mixing: Add the modified wood ash and the composite bio-enzyme to deionized water at a solid-liquid ratio of 1:5-8, place them in a mixing tank, and mix for 30-45 minutes at 30-35℃ and a stirring rate of 30-50 r / min to form a uniform suspension; transfer the suspension to a forced-air drying oven and dry at 60-70℃ for 2-3 hours. After drying, pulverize the powder to a particle size of 100-200 mesh, and sieve to obtain the composite alkaline catalyst.

[0040] Mixing operation: Determine the catalyst dosage based on the sediment test results in step S1 (increase the catalyst dosage by 0.3-0.5 g / L for every 10% increase in the organic matter content of the sediment), and add the catalyst directly to the sewage in the sewage treatment tank; start the stirring device, control the stirring rate at 70-100 r / min, and continue stirring until the catalyst is completely dissolved and dispersed. Avoid generating violent vortices during the stirring process to prevent sewage splashing.

[0041] Step S3: Reaction in the wastewater tank

[0042] Keep the stirring device of the sewage treatment tank running at a speed of 70-100 r / min to maintain the natural ambient temperature inside the tank, allowing the composite alkaline catalyst to react with the suspended sediments in the sewage for 3-4 hours. During the reaction, every 30 minutes, use a pH meter with an accuracy of 0.01 pH to collect sewage samples at three random points on the left, middle, and right sides of the sewage treatment tank, measure the pH value at each point, and calculate the average value. If the average value is lower than 8.0, add composite alkaline catalyst in increments of 0.1-0.2 g / L to ensure that the pH value of the reaction system is stable at 8.0-9.0. This range can maximize the activity of the composite biological enzyme and the alkaline catalytic effect of the wood ash modified material.

[0043] Step S4: Solid-liquid separation

[0044] Settling: After the reaction is complete, turn off the stirring device and let the sewage stand in the sewage treatment tank for 50-60 minutes to allow the sedimented solid sludge in the sewage to settle naturally to the bottom of the tank; during the settling process, do not disturb the sewage to ensure that the sludge settles completely.

[0045] Ceramic membrane filtration: Before filtration, the ceramic membrane needs to be modified for hydrophilicity: a 2% (w / w) polyvinyl alcohol solution (purity ≥99%) is uniformly coated onto the surface of the ceramic membrane, with a coating thickness controlled at 0.2 mm ± 0.02 mm. The membrane is then air-dried at room temperature (20-25℃) for 20-25 minutes to enhance its hydrophilicity. The preferred pore size of the ceramic membrane is 0.1-0.2 μm, the preferred filtration pressure is 0.1-0.2 MPa, and the preferred filtration rate is 1-1.5 m / s. 3 / (m 2 ·h); After filtration, the solid sludge settled at the bottom of the pool and the pre-purified water on the upper layer are obtained.

[0046] Solid sludge conditioning: Solid sludge is discharged through the sludge discharge valve at the bottom of the sewage treatment tank. 5-6% quicklime (CaO content ≥90%) is added to the sludge. The mixture is placed in a mixing tank and stirred for 18-20 minutes at room temperature (20-25℃) and stirring speed (20-30 r / min). After stirring, the moisture content of the sludge is measured by drying method to ensure that the moisture content is reduced to 60-70%. The conditioned sludge is packed into PE material, 0.1mm thick sealed bags for off-site disposal and can be used for roadbed filling or soil improvement.

[0047] Step S5: Deep Wastewater Treatment

[0048] Activated carbon adsorption: Pre-purified water is passed through an activated carbon adsorption column, which is filled with walnut shell-based activated carbon (activated at 900℃, with a specific surface area ≥1000m²). 2 / g), the particle size of activated carbon is controlled at 0.8-1mm; adjust the flow rate of the initial purified water so that the contact time of the wastewater in the adsorption column is 15-20min, so as to fully adsorb residual organic matter and pigments.

[0049] Ultraviolet disinfection: Wastewater after activated carbon adsorption is passed through an ultraviolet disinfection device. The ultraviolet wavelength of the device is fixed at 254nm (which has the highest efficiency in inactivating microorganisms), and the irradiation intensity is controlled at 12-15mW / cm². 2 The number of ultraviolet lamps is configured according to the wastewater discharge volume, with one 30W ultraviolet lamp configured for every 1m³ / h of wastewater treated, ensuring an ultraviolet irradiation dose ≥16mJ / cm². 2 After disinfection, the wastewater meets all the standards and can be directly discharged into the municipal pipe network or natural water bodies.

[0050] The method of this invention significantly improves the degradation efficiency of pollutants through the alkaline environment of the composite alkaline catalyst and the synergistic effect of bio-enzyme catalysis; the optimized solid-liquid separation and deep purification process ensures that the effluent meets the standards and the sludge is harmless. Compared with traditional methods, the treatment cycle is shortened by 20-30%, the pollutant removal rate is increased by 15-25%, and the operating cost is reduced by 10-15%.

[0051] To further illustrate the present invention, the following detailed description is provided through examples, comparative examples, and experimental verification:

[0052] Example 1: Step S1: Sediment detection and high-pressure flushing

[0053] Sediment analysis: 100g of sediment sample was taken from the pipe and dried at 105℃ to constant weight. The mass was 82g after drying and 53.3g after ignition at 550℃. The organic content was calculated to be 28.7% and the inorganic content to be 53.3%.

[0054] High-pressure flushing: A high-pressure water gun is used with a water pressure of 550 bar, a flushing time of 38 minutes, and a nozzle angle of 50°. The flushing wastewater is discharged into a 10m channel through a guide pipe. 3 Wastewater treatment pond.

[0055] Step S2: Addition and mixing of the composite alkaline catalyst

[0056] Preparation of composite alkaline catalysts:

[0057] Step A1: Take 100g of wood ash, calcine at 850℃ for 2.5h, with an aeration rate of 12L / min, and pass through a 100-mesh sieve after cooling; add 5.4% citric acid solution (solid-liquid ratio 1:8.5), and react at 55℃ and 45r / min for 1.8h; after the reaction, wash with deionized water until pH=8.0, and vacuum dry at 85℃ and -0.085MPa for 4.5h to obtain 82g of modified wood ash.

[0058] Step A2: Take 250g of cellulase and 100g of lipase (mass ratio 2.5:1), place them in a constant temperature incubator at 28℃ and 55% humidity and let them stand for 1 hour to activate them, to obtain 345g of compound bio-enzyme.

[0059] Step A3: Take 30g of wood ash modified material and 270g of compound bio-enzyme (mass ratio 1:9), add 2000mL of deionized water (solid-liquid ratio 1:6.7), mix at 32℃ and 40r / min for 38min; dry at 65℃ for 2.5h, and pulverize to 150 mesh to obtain 290g of compound alkaline catalyst.

[0060] Mixing operation: Based on the organic matter content of 28.7%, the catalyst dosage is determined to be 1.2 g / L (total dosage of 12 g per 10 m³ of wastewater); 12 g of catalyst is added to the wastewater treatment tank, the stirring device is started at a speed of 85 r / min, and stirring is continued for 25 min until the catalyst is completely dispersed.

[0061] Step S3: Reaction in the wastewater tank

[0062] Maintain the ambient temperature of the wastewater treatment tank at 25℃, the stirring rate at 85r / min, and the reaction time at 3.5h. Measure the pH value at three points (left, middle, and right) every 30 minutes. The average value is 8.5, and no catalyst needs to be added.

[0063] Step S4: Solid-liquid separation

[0064] Settling: Turn off the stirring device and let the sewage stand for 55 minutes until the solid sludge settles to the bottom of the pool.

[0065] Ceramic membrane filtration: The ceramic membrane is coated with a 2% polyvinyl alcohol solution to a thickness of 0.2 mm and air-dried at room temperature for 22 min; the membrane pore size is 0.15 μm, the filtration pressure is 0.15 MPa, and the filtration rate is 1.2 m / s². 3 / (m 2 ·h), yielding 9.2m³ of pre-purified water. 3 .

[0066] Solid sludge conditioning: 1.5t of sludge was discharged from the bottom of the pool, 82.5kg of quicklime with a mass fraction of 5.5% was added, and the mixture was stirred at 23℃ and 25r / min for 19min; the moisture content of the sludge was measured to be 65%, and the mixture was packed into sealed bags for transport.

[0067] Step S5: Deep Wastewater Treatment

[0068] Activated carbon adsorption: The pre-purified water is passed into the activated carbon adsorption column. The activated carbon particle size is 0.9 mm. The flow rate is adjusted so that the wastewater is in contact with the column for 18 minutes.

[0069] Ultraviolet disinfection: The ultraviolet disinfection device has a wavelength of 254nm and an irradiation intensity of 13.5mW / cm². 2 Wastewater discharge volume 2m 3 / h, equipped with 2 30W ultraviolet lamps, ultraviolet irradiation dose 18mJ / cm 2 Discharged water after disinfection.

[0070] Example 2: Step S1: Sediment detection and high-pressure flushing

[0071] Sediment analysis: 100g of sediment sample was dried at 105℃ and weighed 78g. After ignition at 550℃, the weight was 46.8g. The organic content was calculated to be 31.2% and the inorganic content to be 46.8%.

[0072] High-pressure flushing: 520 bar water pressure from the high-pressure water gun, flushing time 36 minutes, nozzle angle 48°, flushing wastewater discharged into a 10m... 3 Wastewater treatment pond.

[0073] Step S2: Addition and mixing of the composite alkaline catalyst

[0074] Preparation of composite alkaline catalysts:

[0075] Step A1: Take 100g of wood ash, calcine at 820℃ for 2.2h, with an aeration rate of 11L / min, and pass through a 100-mesh sieve after cooling; add a 5.2% malic acid solution (solid-liquid ratio 1:7.5), and react at 52℃ and 42r / min for 1.6h; after the reaction, wash with deionized water until pH=7.8, and vacuum dry at 82℃ and -0.082MPa for 4.2h to obtain 80g of modified wood ash.

[0076] Step A2: Take 200g of cellulase and 100g of lipase (mass ratio 2:1), place them in a constant temperature incubator at 26℃ and 52% humidity and let them stand for 1 hour to activate them, to obtain 295g of compound bio-enzyme.

[0077] Step A3: Take 30g of wood ash modified material and 240g of compound bio-enzyme (mass ratio 1:8), add 1800mL of deionized water (solid-liquid ratio 1:6), mix at 31℃ and 35r / min for 35min; dry at 62℃ for 2.2h, and pulverize to 120 mesh to obtain 260g of compound alkaline catalyst.

[0078] Mixing operation: Based on an organic matter content of 31.2%, the catalyst dosage was determined to be 1.3 g / L (10m³). 3 (Total amount of wastewater added: 13g); Add 13g of catalyst to the wastewater treatment tank, start the stirring device at a rate of 75r / min, and continue stirring for 28min until the catalyst is completely dispersed.

[0079] Step S3: Reaction in the wastewater tank

[0080] The ambient temperature of the wastewater treatment tank was maintained at 23℃, the stirring rate at 75r / min, and the reaction time at 3.2h. The pH value was measured at three points every 30min, and the average value was 8.2. No catalyst was required to be added.

[0081] Step S4: Solid-liquid separation

[0082] Settling: Turn off the stirring device and let the sewage stand for 52 minutes until the solid sludge settles to the bottom of the pool.

[0083] Ceramic membrane filtration: The ceramic membrane is coated with a 2% polyvinyl alcohol solution, 0.2 mm thick, and air-dried at room temperature for 21 min; the membrane pore size is 0.12 μm, the filtration pressure is 0.13 MPa, and the filtration rate is 1.1 m / s². 3 / (m 2 ·h), yielding 9.0m³ of pre-purified water. 3 .

[0084] Solid sludge conditioning: 1.6t of sludge was discharged from the bottom of the pool, 83.2kg of quicklime with a mass fraction of 5.2% was added, and the mixture was stirred at 22℃ and 22r / min for 18min; the moisture content of the sludge was measured to be 63%, and it was packed into sealed bags for transport.

[0085] Step S5: Deep Wastewater Treatment

[0086] Activated carbon adsorption: The pre-purified water is passed into the activated carbon adsorption column. The activated carbon particle size is 0.8 mm. The flow rate is adjusted so that the wastewater is in contact with the column for 16 minutes.

[0087] Ultraviolet disinfection: The ultraviolet disinfection device has a wavelength of 254nm and an irradiation intensity of 12.5mW / cm². 2 Wastewater discharge is 1.8 m³ / h, equipped with two 30W ultraviolet lamps, with an ultraviolet irradiation dose of 17 mJ / cm². 2 Discharged water after disinfection.

[0088] Example 3: Step S1: Sediment detection and high-pressure flushing

[0089] Sediment analysis: 100g of sediment sample was dried at 105℃ and weighed 85g. After ignition at 550℃, the weight was 59.5g. The organic content was calculated to be 25.5% and the inorganic content to be 59.5%.

[0090] High-pressure flushing: High-pressure water gun with a water pressure of 580 bar, flushing time of 39 minutes, nozzle angle of 55°, and flushing wastewater discharged into a 10m³ wastewater treatment tank.

[0091] Step S2: Addition and mixing of the composite alkaline catalyst

[0092] Preparation of composite alkaline catalysts:

[0093] Step A1: Take 100g of wood ash, calcine at 880℃ for 2.8h, with an aeration rate of 14L / min, and pass through a 100-mesh sieve after cooling; add a 5.6% citric acid solution (solid-liquid ratio 1:9), and react at 58℃ and 48r / min for 1.9h; after the reaction, wash with deionized water until pH=8.2, and vacuum dry at 88℃ and -0.088MPa for 4.8h to obtain 83g of modified wood ash.

[0094] Step A2: Take 300g of cellulase and 100g of lipase (mass ratio 3:1), place them in a constant temperature incubator at 30℃ and 58% humidity and let them stand for 1 hour to activate them, to obtain 390g of compound bio-enzyme.

[0095] Step A3: Take 30g of wood ash modified material and 300g of compound bio-enzyme (mass ratio 1:10), add 2200mL of deionized water (solid-liquid ratio 1:7.3), mix at 34℃ and 45r / min for 42min; dry at 68℃ for 2.8h, and pulverize to 180 mesh to obtain 320g of compound alkaline catalyst.

[0096] Mixing operation: Based on an organic matter content of 25.5%, the catalyst dosage was determined to be 1.1 g / L (10m³). 3 (Total amount of wastewater added: 11g); Add 11g of catalyst to the wastewater treatment tank, start the stirring device at a speed of 70r / min, and continue stirring for 30min until the catalyst is completely dispersed.

[0097] Step S3: Reaction in the wastewater tank

[0098] The ambient temperature of the wastewater treatment tank was maintained at 27℃, the stirring rate at 70 r / min, and the reaction time at 3.8 h. The pH value was measured at three points every 30 min, and the average value was 8.6. No catalyst was required to be added.

[0099] Step S4: Solid-liquid separation

[0100] Settling: Turn off the stirring device and let the sewage stand for 58 minutes until the solid sludge settles to the bottom of the pool.

[0101] Ceramic membrane filtration: The ceramic membrane is coated with a 2% polyvinyl alcohol solution to a thickness of 0.2 mm and air-dried at room temperature for 24 min; the membrane pore size is 0.18 μm, the filtration pressure is 0.18 MPa, and the filtration rate is 1.4 m / s². 3 / (m2 ·h), yielding 9.4m³ of initially purified water. 3 .

[0102] Solid sludge conditioning: 1.4t of sludge was discharged from the bottom of the pool, 81.2kg of quicklime with a mass fraction of 5.8% was added, and the mixture was stirred at 24℃ and 28r / min for 20min; the moisture content of the sludge was measured to be 68%, and it was packed into sealed bags for transport.

[0103] Step S5: Deep Wastewater Treatment

[0104] Activated carbon adsorption: Pass the pre-purified water into the activated carbon adsorption column. The activated carbon particle size is 1.0 mm. Adjust the flow rate to make the wastewater contact time in the column 20 minutes.

[0105] Ultraviolet disinfection: The ultraviolet disinfection device has a wavelength of 254nm and an irradiation intensity of 14.5mW / cm². 2 Wastewater discharge: 2.2m³ 3 / h, equipped with 3 30W ultraviolet lamps, ultraviolet irradiation dose 19mJ / cm 2 Discharged water after disinfection.

[0106] Example 4: Step S1: Sediment detection and high-pressure flushing

[0107] Sediment analysis: Take 100g of sediment sample, dry at 105℃ to a mass of 75g, and burn at 550℃ to a mass of 45g. Calculate that the organic content is 30% and the inorganic content is 60%.

[0108] High-pressure flushing: High-pressure water gun with a water pressure of 500 bar, flushing time of 35 minutes, nozzle angle of 45°, and flushing wastewater discharged into a 10m³ wastewater treatment tank.

[0109] Step S2: Addition and mixing of the composite alkaline catalyst

[0110] Preparation of composite alkaline catalysts:

[0111] Step A1: Take 100g of wood ash, calcine at 800℃ for 2h with an aeration rate of 10L / min, cool and pass through a 100-mesh sieve; add 5.0% citric acid solution (solid-liquid ratio 1:7), react at 50℃ and 40r / min for 1.5h; after reaction, wash with deionized water until pH=7.5, and vacuum dry at 80℃ and -0.08MPa for 4h to obtain 78g of modified wood ash.

[0112] Step A2: Take 220g of cellulase and 100g of lipase (mass ratio 2.2:1), place them in a constant temperature incubator at 25℃ and 50% humidity and let them stand for 1 hour to activate them, to obtain 315g of compound bio-enzyme.

[0113] Step A3: Take 30g of wood ash modified material and 270g of compound bio-enzyme (mass ratio 1:9), add 1950mL of deionized water (solid-liquid ratio 1:6.5), mix at 30℃ and 30r / min for 30min; dry at 60℃ for 2h, and pulverize to 100 mesh to obtain 290g of compound alkaline catalyst.

[0114] Mixing operation: Based on an organic matter content of 30%, the catalyst dosage is determined to be 1.2 g / L (10m³). 3 (Total dosage of wastewater: 12g); Add 12g of catalyst to the wastewater treatment tank, start the stirring device at a speed of 90r / min, and continue stirring for 22min until the catalyst is completely dispersed.

[0115] Step S3: Reaction in the wastewater tank

[0116] Maintain the ambient temperature of the wastewater treatment tank at 20℃, the stirring rate at 90r / min, and the reaction time at 3h; measure the pH value at three points every 30min, with an average value of 8.1, and no catalyst needs to be added.

[0117] Step S4: Solid-liquid separation

[0118] Settling: Turn off the stirring device and let the sewage stand for 50 minutes until the solid sludge settles to the bottom of the pool.

[0119] Ceramic membrane filtration: The ceramic membrane is coated with a 2% polyvinyl alcohol solution to a thickness of 0.2 mm and air-dried at room temperature for 20 min; the membrane pore size is 0.1 μm, the filtration pressure is 0.1 MPa, and the filtration rate is 1.0 m / s². 3 / (m 2 ·h), yielding 8.9m³ of pre-purified water. 3 .

[0120] Solid sludge conditioning: 1.7t of sludge was discharged from the bottom of the pool, 85kg of quicklime with a mass fraction of 5.0% was added, and the mixture was stirred at 20℃ and 20r / min for 18min; the moisture content of the sludge was measured to be 60%, and the mixture was packed into sealed bags for transport.

[0121] Step S5: Deep Wastewater Treatment

[0122] Activated carbon adsorption: Pass the pre-purified water into the activated carbon adsorption column. The activated carbon particle size is 0.8 mm. Adjust the flow rate so that the wastewater is in contact with the column for 15 minutes.

[0123] Ultraviolet disinfection: The ultraviolet disinfection device has a wavelength of 254nm and an irradiation intensity of 15mW / cm². 2 Wastewater discharge: 1.5m³ 3 / h, equipped with one 30W ultraviolet lamp, ultraviolet irradiation dose 20mJ / cm 2 Discharged water after disinfection.

[0124] Example 5: Step S1: Sediment detection and high-pressure flushing

[0125] Sediment analysis: Take 100g of sediment sample, dry at 105℃ to a mass of 80g, and burn at 550℃ to a mass of 52g. Calculate that the organic content is 28% and the inorganic content is 52%.

[0126] High-pressure flushing: High-pressure water gun with a water pressure of 600 bar, flushing time of 40 minutes, nozzle angle of 60°, and flushing wastewater discharged into a 10m³ wastewater treatment tank.

[0127] Step S2: Addition and mixing of the composite alkaline catalyst

[0128] Preparation of composite alkaline catalysts:

[0129] Step A1: Take 100g of wood ash, calcine at 900℃ for 3h with an aeration rate of 15L / min, cool and pass through a 100-mesh sieve; add a 5.8% malic acid solution (solid-liquid ratio 1:10), react at 60℃ and 50r / min for 2h; after the reaction, wash with deionized water until pH=8.5, and vacuum dry at 90℃ and -0.09MPa for 5h to obtain 85g of modified wood ash;

[0130] Step A2: Take 280g of cellulase and 100g of lipase (mass ratio 2.8:1), place them in a constant temperature incubator at 30℃ and 60% humidity and let them stand for 1 hour to fully activate the enzyme activity, and obtain 375g of compound bio-enzyme.

[0131] Step A3: Take 30g of wood ash modified material and 300g of compound bio-enzyme (mass ratio 1:10), add 2150mL of deionized water (solid-liquid ratio 1:7.2), transfer to a mixing tank, mix at 35℃ and 50r / min for 45min to form a uniform suspension; transfer the suspension to a forced-air drying oven, dry at 70℃ for 3h, after drying, pulverize to 200 mesh with a pulverizer, and after sieving, obtain 325g of compound alkaline catalyst.

[0132] Mixing operation: Based on the organic matter content of the sediment of 28% in step S1, the dosage of composite alkaline catalyst is determined to be 1.2g / L (total dosage of 12g for a 10m³ wastewater treatment tank); 12g of catalyst is added directly to the wastewater, the stirring device is started, the stirring rate is 100r / min, and stirring is continued for 26min until the catalyst is completely dissolved and dispersed.

[0133] Step S3: Reaction in the wastewater tank

[0134] The ambient temperature of the wastewater treatment tank was maintained at 28℃, and the stirring device was kept running at a rate of 100r / min to allow the catalyst to react with the suspended sediment for 4 hours. During the reaction, the pH value of the wastewater at three points (left, middle, and right) in the tank was measured every 30 minutes using a pH meter. The calculated average value was stable at 8.4, and no additional catalyst was required.

[0135] Step S4: Solid-liquid separation

[0136] Settling: After the reaction is complete, turn off the agitator and let the wastewater stand in the wastewater treatment tank for 60 minutes until the solid sludge completely settles to the bottom of the tank.

[0137] Ceramic membrane filtration: The ceramic membrane is pre-coated with a 2% (w / w) polyvinyl alcohol solution to a thickness of 0.2 mm and allowed to air dry at room temperature for 25 min; the membrane pore size is 0.2 μm, the filtration pressure is 0.2 MPa, and the filtration rate is controlled at 1.5 m / s. 3 / (m 2 •h), after filtration, 9.5m of pre-purified water was obtained. 3 .

[0138] Solid sludge conditioning: 1.5t of sludge was discharged through the sludge discharge valve at the bottom of the pool. 84kg of quicklime with a mass fraction of 5.6% was added to the sludge and transferred to a mixing kettle. The mixture was stirred for 20min at 25℃ and 30r / min. After stirring, the moisture content of the sludge was measured to be 66%. The sludge was then packed into PE sealed bags for external disposal.

[0139] Step S5: Deep Wastewater Treatment

[0140] Activated carbon adsorption: The pre-purified water is passed into the activated carbon adsorption column, which is filled with walnut shell-based activated carbon (particle size 0.9 mm). The water flow rate is adjusted so that the contact time of the wastewater in the adsorption column is 19 minutes to fully adsorb the residual organic matter.

[0141] Ultraviolet disinfection: After adsorption, the wastewater is passed into an ultraviolet disinfection device with a wavelength of 254nm and an irradiation intensity of 14mW / cm²; the wastewater discharge volume is 2.1m³. 3 / h, per 1m 3 The standard configuration is one 30W UV lamp per hour, with a total of three lamps, providing a UV irradiation dose of 18.5mJ / cm². After disinfection, all effluent indicators meet the standards and are discharged directly.

[0142] Comparative Example 1: Step S1: Sediment Detection and High-Pressure Erosion

[0143] Completely consistent with Example 1: the organic matter content of the sediment was 28.7% and the inorganic matter content was 53.3%; the high-pressure water gun had a water pressure of 550 bar, the flushing time was 38 minutes, and the sewage was discharged into a 10 m³ sewage treatment tank.

[0144] Step S2: Catalyst addition and mixing

[0145] Using only compound bio-enzymes (without wood ash modifiers): Take 250g of cellulase and 100g of lipase (mass ratio 2.5:1), activate at 28℃ for 1h to obtain compound bio-enzymes; add to wastewater at a dosage of 1.2g / L (total dosage 12g), and stir at 85r / min for 25min.

[0146] Steps S3-S5

[0147] Completely consistent with Example 1: reaction for 3.5 h (average pH 7.2, not reaching 8.0-9.0), standing for 55 min, filtration after modification with ceramic filter membrane, activated carbon adsorption (18 min), and ultraviolet disinfection (dose 18 mJ / cm²).

[0148] Comparative Example 2: Steps S1-S3 were completely consistent with Example 1: the sediment detection results were the same, the high-pressure flushing parameters were the same, and the addition of the composite alkaline catalyst (wood ash modified material, biological enzyme) and the reaction conditions were the same (average pH 8.5).

[0149] Step S4: Solid-liquid separation

[0150] Ceramic filter membrane used directly (without polyvinyl alcohol coating): filter membrane pore size 0.15μm, pressure 0.15MPa, other steps such as standing (55min) and sludge conditioning (add 82.5kg of 5.5% quicklime and stir at 23℃ for 19min) are the same as in Example 1.

[0151] Step S5: Deep Wastewater Treatment

[0152] Completely consistent with Example 1: activated carbon adsorption (18 min), ultraviolet disinfection (dose 18 mJ / cm²).

[0153] Experimental verification

[0154] To verify the purification effect of the method of the present invention, COD removal rate and suspended solids (SS) removal rate were selected and tested according to national standard methods. The test data are as follows:

[0155] Experiment 1: COD Removal Rate Detection

[0156] Referring to GB / T11914-2024: Wastewater before treatment and effluent after treatment in each example and comparative example were taken, and the COD value was determined using the potassium dichromate oxidation-ferrous ammonium sulfate titration method. The removal rate was calculated.

[0157] Removal rate = (Influent COD - Effluent COD) / Influent COD × 100%, the results are as follows:

[0158] Table 1

[0159]

[0160] As shown in Table 1, the COD removal rate of Examples 1-5 all reached over 93%. The core reason is the synergistic effect of the composite alkaline catalyst: the wood ash modifier provides an alkaline environment of 8.0-9.0, which can destroy the adhesion structure of the sediment; the composite bio-enzyme maximizes its activity within this pH range and targets the degradation of organic matter. The two work together to promote the efficient removal of COD.

[0161] Experiment 2: Detection of suspended solids (SS) removal rate

[0162] Referring to GB / T11901-1989: Take the influent and effluent of each group, filter them through a 0.45μm microporous membrane, dry them at 105℃ to constant weight, and calculate the SS removal rate:

[0163] Removal rate = (Influent SS - Effluent SS) / Influent SS × 100%, the results are as follows:

[0164] Table 2

[0165]

[0166] As can be seen from Table 2, the SS removal rate of Examples 1-5 reached over 96%, which is mainly due to the dual effects of catalytic flocculant breaking and modified filter membrane retention: the composite alkaline catalyst destroys the adhesion structure of the sediment, dispersing the suspended matter into easily settling particles; the ceramic filter membrane is modified with polyvinyl alcohol, which enhances its hydrophilicity, makes it less prone to clogging, and can efficiently retain suspended particles.

[0167] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for dredging and purifying drainage pipes and channels, characterized in that, Includes the following steps: S1: Sediment Detection and High-Pressure Flushing: Detect the organic and inorganic content of the drainage pipes and channels; then flush the sediment in the pipes and channels with a high-pressure water gun, and discharge the flushed wastewater into the sewage treatment pond; S2: Addition and mixing of composite alkaline catalyst: Based on the sediment detection results in step S1, the composite alkaline catalyst is directly added to the wastewater in the wastewater treatment tank. The composite alkaline catalyst is composed of wood ash modified material and composite biological enzyme at a mass ratio of 1:8-10, which has the synergistic effect of providing an alkaline environment and targeted catalysis by biological enzymes, and can efficiently destroy the adhesion structure of suspended sediments in wastewater. The composite biological enzyme is composed of cellulase with an enzyme activity ≥1000U / g and lipase with an enzyme activity ≥800U / g at a mass ratio of 2-3:

1. The wastewater treatment tank is stirred at a stirring rate of 70-100r / min, and stirring is continued. S3: Reaction in the wastewater treatment tank: Maintain the natural ambient temperature in the wastewater treatment tank to allow the composite alkaline catalyst to react with the suspended sediments in the wastewater for 3-4 hours; During the reaction, monitor the pH value of the wastewater in the wastewater treatment tank every 30 minutes, randomly take the average pH value of three points, and maintain the pH value at 8.0-9.

0. If the average value is lower than 8.0, add composite alkaline catalyst in increments of 0.1-0.2 g / L. S4: Solid-liquid separation: After the reaction is complete, stop stirring and let the sewage stand in the sewage treatment tank for 50-60 minutes to allow the sedimentary solid sludge to settle to the bottom of the tank; the upper suspended sewage is filtered through a ceramic filter membrane, and the filtered solid sludge settled at the bottom of the tank and the upper pre-purified water are obtained. S5: Deep wastewater purification: The pre-purified water from step S4 is passed sequentially through an activated carbon adsorption column and an ultraviolet disinfection device. The activated carbon adsorption column has an activated carbon particle size of 0.8-1 mm and a contact time of 15-20 min; the ultraviolet disinfection device has an ultraviolet wavelength of 254 nm and an irradiation intensity of 12-15 mW / cm², and the effluent meets the discharge standards. The preparation method of the composite alkaline catalyst in step S2 includes the following steps: A1: Preparation of modified plant ash: Take plant ash, and obtain modified plant ash by high-temperature activation, organic acid modification, washing and drying; the high-temperature activation conditions are calcination at 800-900℃ for 2-3 hours, and cooling to room temperature and passing through a 100-mesh sieve. A2: Preparation of composite bioenzyme: Cellulase and lipase are mixed in a mass ratio and activated by standing at 25-30℃ for 1 hour to obtain composite bioenzyme; A3: Compound mixing: Add the wood ash modified product from step A1 and the composite bio-enzyme from step A2 to deionized water, mix for 30-45 min at a temperature of 30-35℃ and a stirring rate of 30-50 r / min, then dry at 60-70℃ for 2-3 h, and pulverize to a particle size of 100-200 mesh to obtain a composite alkaline catalyst; The specific conditions for organic acid modification and cleaning and drying in step A1 are as follows: The high-temperature activated wood ash is added to an organic acid solution with a mass concentration of 5-5.8%, and the solid-liquid ratio of wood ash to organic acid solution is 1:7-10. The reaction is carried out at 50-60℃ and a stirring rate of 40-50 r / min for 1.5-2 h. After the reaction is completed, the product is washed with deionized water until the pH value is 7.5-8.5, and then vacuum dried at 80-90℃ and a vacuum degree of -0.08 to -0.09 MPa for 4-5 h to obtain the modified wood ash. The flocculating effect of wood ash provides more degradation sites for biological enzymes, which in turn convert the flocculated organic matter into easily processed small molecules.

2. The drainage pipe and channel dredging and purification method according to claim 1, characterized in that, The water pressure of the high-pressure water gun in step S1 is 500-600 bar, and the rinsing time is 35-40 minutes.

3. The drainage pipe and channel dredging and purification method according to claim 1, characterized in that, The organic acid solution is selected from citric acid and malic acid.

4. The drainage pipe and channel dredging and purification method according to claim 1, characterized in that, Before filtration, the ceramic filter membrane described in step S4 needs to be modified for hydrophilicity. Specifically, it is coated with a 2% polyvinyl alcohol solution with a coating thickness of 0.2mm ± 0.02mm. After coating, it is air-dried at room temperature for 20-25 minutes to reduce the filter membrane clogging rate.

5. The drainage pipe and channel dredging and purification method according to claim 1, characterized in that, The solid sludge obtained in step S4 is discharged through the sludge discharge valve at the bottom of the sewage tank. After discharge, 5-6% quicklime is added for conditioning. The conditioning conditions are: stirring and mixing at room temperature of 20-25℃ for 18-20 minutes at a stirring rate of 20-30 r / min until the moisture content of the sludge drops to 60-70%. After conditioning, it is packed into sealed bags for external disposal.

6. The drainage pipe and channel dredging and purification method according to claim 1, characterized in that, The ceramic filter membrane described in step S4 has a pore size of 0.1-0.2 μm and a filtration pressure of 0.1-0.2 MPa.

7. The drainage pipe and channel dredging and purification method according to claim 1, characterized in that, The activated carbon in the activated carbon adsorption column in step S5 is walnut shell-based activated carbon, which is activated at 900℃ and has a specific surface area ≥1000m² / g.

8. The drainage pipe and channel dredging and purification method according to claim 1, characterized in that, The number of lamps in the ultraviolet disinfection device described in step S5 is configured according to the amount of sewage discharged. One 30W ultraviolet lamp is configured for every 1m³ / h of sewage treated, and the ultraviolet irradiation dose is ≥16mJ / cm².

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