Method for treating rural sewage by natural freezing mode
By treating rural sewage through the natural freezing method combined with composite adsorption materials and ecological floating island technology, the problem of high cost of rural sewage treatment facilities is solved, and low-energy consumption and high-efficiency sewage treatment effects are achieved.
Patent Information
- Application Number
- CN202510850302.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-24
- Publication Date
- 2025-09-16
- Estimated Expiration
- 2045-06-24
AI Technical Summary
The construction, operation and maintenance costs of rural sewage treatment facilities are high, and traditional centralized treatment models are difficult to apply. The sewage contains high levels of organic matter and pollutants such as nitrogen and phosphorus, which affect the environment and crop growth.
The natural freezing method is used to treat rural sewage. Through grid sedimentation and composite adsorption material pretreatment, the sewage is frozen and concentrated by natural cooling, and the concentrated sewage is treated with ecological floating island technology. After the ice melts, it is used for landscape and agricultural irrigation.
It effectively reduces the content of microorganisms and pollutants in rural sewage. It is simple to operate and low-cost. It is suitable for rural areas in the north and realizes low-energy sewage treatment.
Smart Images
Figure CN120647068A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a method for treating rural sewage by utilizing natural freezing. Background Art
[0002] With the rapid development of the rural economy and the continuous growth of the rural population, the discharge of domestic sewage in rural areas has increased, while the corresponding sewage treatment facilities have lagged behind. This has led to the direct discharge of untreated sewage into natural water bodies such as rivers and lakes, polluting the rural environment and threatening rural drinking water security and ecological balance. Especially in some remote and economically underdeveloped rural areas, due to funding, technical and management limitations, establishing and maintaining efficient sewage treatment systems faces enormous challenges.
[0003] Rural sewage discharge is dispersed, with small and volatile volumes and complex water quality. This makes traditional centralized sewage treatment models difficult to effectively apply. Furthermore, rural areas generally lack professional sewage treatment technology and personnel, and funding shortages make the construction, operation, and maintenance of sewage treatment facilities expensive, making them difficult to popularize. Furthermore, rural sewage contains high levels of pollutants such as organic matter, nitrogen, and phosphorus. If improperly treated, this can not only cause eutrophication of water bodies but also affect crop growth and soil quality, further exacerbating the deterioration of the rural environment.
[0004] Therefore, the search for a cost-effective, efficient, and environmentally friendly sewage treatment method is urgent. Driven by this need, the use of natural freezing to treat rural sewage has gradually emerged as an innovative solution. This method cleverly utilizes the naturally low temperatures of winter in cold regions, integrating sewage treatment with the natural environment to achieve a low-cost, low-energy, and environmentally friendly treatment approach. Summary of the Invention
[0005] The purpose of the present invention is to provide a method for treating rural sewage by utilizing natural freezing, so as to solve the technical problem of poor rural sewage treatment in the prior art.
[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides a method for treating rural sewage by utilizing natural freezing, comprising the following steps: Step 1: The collected rural sewage is passed through a screen and flows into a grit chamber for sedimentation, the pH is adjusted, and composite adsorption materials are added for adsorption treatment. After the adsorption treatment is completed, the composite adsorption materials are removed to obtain pretreated rural sewage; Step 2: Add pretreated rural sewage to the water storage tank, and then discharge it into the primary treatment tank, secondary treatment tank, tertiary treatment tank and quaternary treatment tank in sequence. The quaternary treatment tank is connected to the sludge tank. Natural cooling and freezing are used to move the ice in the primary treatment tank, secondary treatment tank, tertiary treatment tank and quaternary treatment tank into the ice storage tank. The sewage is then discharged into the next treatment tank in sequence, and the operation is repeated. Step 3: After the temperature rises, the ecological floating island technology is used to treat the mixed sewage in the sludge pool, and the ice in the ice storage pool is melted and used for rural landscaping and agricultural irrigation.
[0007] Preferably, in step 1, the grid pitch is ≤20 mm, the precipitation time is ≥30 min, lime or ferrous sulfate is added to adjust the pH to 6-8, and the adsorption treatment time is 60-90 min.
[0008] Preferably, in step 1, the method for preparing the composite adsorption material comprises the following steps: Q1: Sodium hyaluronate was added to MES buffer and stirred to mix. Then, 4-(4,6-dimethoxy-1,3,5-triazine-2-yl)-4-methylmorpholine chloride was added and stirring was continued. Then, methylaminoacetaldehyde dimethyl acetal was added. The mixture was heated with stirring and refluxed under condensation. After the reflux period, the mixture was dialyzed and freeze-dried to obtain an intermediate. Q2: Add the intermediate to deionized water, hydrolyze with acid, adjust the pH, let stand, and dialyze to obtain modified sodium hyaluronate; Q3: Add polyvinyl alcohol to deionized water, heat and stir to dissolve to obtain a polyvinyl alcohol solution, add modified sodium hyaluronate to deionized water, stir to dissolve to obtain a modified sodium hyaluronate solution, add polyacrylic acid to deionized water, stir and mix evenly to obtain a polyacrylic acid solution, then, mix the polyvinyl alcohol solution, modified sodium hyaluronate solution and polyacrylic acid solution evenly to obtain an electrospinning solution, obtain a nanofilm through electrospinning technology, heat to react, wash, and freeze-dry to obtain a composite adsorption material.
[0009] In the above process, the synthetic reaction formula of modified sodium hyaluronate is as follows:
[0010] Preferably, in Q1, the dosage ratio of sodium hyaluronate, MES buffer, 4-(4,6-dimethoxy-1,3,5-triazine-2-yl)-4-methylmorpholine chloride and methylaminoacetaldehyde dimethyl acetal is (1-1.5) g: (120-200) mL: (0.62-0.95) g: (0.14-0.22) g, the concentration of MES buffer is 0.1 mol / L, pH = 5.5, the stirring time is continued for 15-30 min, the heating and stirring temperature is 60-65° C., and the heating time is 20-24 h. During the dialysis process, the molecular retention capacity of the dialysis bag is 14 kDa, and the product is first dialyzed with 0.1 mol / L sodium chloride solution for 2 days, and then dialyzed with deionized water for 1 day.
[0011] Preferably, in Q2, the ratio of the intermediate to deionized water is (1-1.8) g: (100-180) mL, acid hydrolysis is performed with 0.2 mol / L hydrochloric acid solution for 2 days, the pH is adjusted to 3.8-4.2 with 0.1 mol / L sodium bicarbonate solution, the standing time is 10-12 h, and dialyzed with deionized water for 2-3 days.
[0012] Preferably, in Q3, the heating and stirring temperature is 88-92°C, the usage ratio of polyvinyl alcohol solution, modified sodium hyaluronate solution and polyacrylic acid solution is (30-45) g: (2-3) g: (20-28) g, the heating reaction temperature is 110-125°C, the reaction time is 6-8 h, and the product is washed with distilled water for 48-52 h.
[0013] Preferably, in the step 2, the area of the water storage tank is 6 mu and the height is 6 m. When the temperature of the water storage tank is below 0°C, the water does not freeze. The area of the first-level treatment tank is 54 mu and the height is 0.6 m. The area of the second-level treatment tank is 9 mu and the height is 0.6 m. The area of the third-level treatment tank is 1.5 mu and the height is 0.6 m. The area of the fourth-level treatment tank is 0.25 mu and the height is 0.6 m. The area of the ice storage tank is 6 mu and the height is 10 m. Cement columns with a spacing of 2 m and a height of 0.1 m are installed in the first to fourth-level treatment tanks.
[0014] Preferably, in the step 2, when the ice body is frozen to a thickness of 50 cm, the ice body is removed to the ice storage tank, and the sewage is discharged into the next-level treatment tank in sequence. The treatment order is: the sewage in the fourth-level treatment tank is discharged into the sludge tank, the sewage in the third-level treatment tank is discharged into the fourth-level treatment tank, the sewage in the second-level treatment tank is discharged into the third-level treatment tank, and the sewage in the first-level treatment tank is discharged into the second-level treatment tank.
[0015] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: The present invention first uses sodium hyaluronate, methylaminoacetaldehyde dimethyl acetal, polyvinyl alcohol and polyacrylic acid as raw materials to prepare a composite adsorption material. This material is green, environmentally friendly and reusable. The composite adsorption material is applied to the pretreatment process of rural sewage to effectively reduce the content of microorganisms and bacteria in the rural sewage. Subsequently, the pretreated rural sewage is concentrated by natural freezing, thereby efficiently concentrating the COD, TN and TP in the sewage. Finally, the concentrated sewage is treated using ecological floating island technology, and the ice with a low pollutant concentration is collected and used for rural landscaping and agricultural irrigation. The entire process is simple to operate, low in cost and low in operating expenses, and is suitable for rural areas in the north. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0017] Figure 1 The present invention is a flow chart of a method for treating rural sewage by utilizing natural freezing. DETAILED DESCRIPTION
[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0019] Example 1: This example discloses a method for preparing a composite adsorption material, comprising the following steps: Q1: Add 1.25 g of sodium hyaluronate to 100 mL of 0.1 mol / L MES buffer at pH 5.5, stir and mix, then add 0.78 g of 4-(4,6-dimethoxy-1,3,5-triazine-2-yl)-4-methylmorpholine chloride, continue stirring for 30 min, then add 0.18 g of methylaminoacetaldehyde dimethyl acetal, heat and stir at 60°C for 24 h, condense and reflux, and after reflux, dialyze with a molecular cutoff of 14 kDa using a dialysis bag. First, dialyze with 0.1 mol / L sodium chloride solution for 2 days, then dialyze with deionized water for 1 day, and lyophilize to obtain an intermediate. Q2: Add 1.4 g of the intermediate to 140 mL of deionized water, hydrolyze with 0.2 mol / L hydrochloric acid solution for 2 days, adjust the pH to 4 with 0.1 mol / L sodium bicarbonate solution, let stand for 12 hours, and dialyze with deionized water for 3 days to obtain modified sodium hyaluronate; Q3: Add 2.4 g of polyvinyl alcohol to 26.7 mL of deionized water, heat and stir at 90°C to dissolve to obtain a polyvinyl alcohol solution, add 1 g of modified sodium hyaluronate to 100 mL of deionized water, stir and dissolve to obtain a modified sodium hyaluronate solution, add 1.8 g of polyacrylic acid to 24.8 mL of deionized water, stir and mix evenly to obtain a polyacrylic acid solution, then, mix 37.5 g of polyvinyl alcohol solution, 2.5 g of modified sodium hyaluronate solution and 24 g of polyacrylic acid solution evenly to obtain an electrospinning solution, and obtain a nanomembrane through electrospinning technology. Heat the reaction at 115°C for 8 h, wash with distilled water for 48 h, and freeze-dry to obtain a composite adsorption material.
[0020] See Figure 1 As shown, this embodiment provides a method for treating rural sewage by using natural freezing, comprising the following steps: Step 1: The collected rural sewage is passed through a screen with a grid pitch of ≤20mm and flows into a grit chamber for 30 minutes. Lime or ferrous sulfate is added to adjust the pH to 7. Composite adsorption material is added for adsorption treatment for 90 minutes. After the adsorption treatment is completed, the composite adsorption material is removed to obtain pretreated rural sewage. Step 2: Add the pre-treated rural sewage to the water storage tank (area of 6 mu, height of 6m, when the temperature of the water storage tank is below 0℃, the water body will not freeze), and then discharge it into the primary treatment tank (area of 54 mu, height of 0.6m), secondary treatment tank (area of 9 mu, height of 0.6m), tertiary treatment tank (area of 1.5 mu, height of 0.6m) and quaternary treatment tank (area of 0.25 mu, height of 0.6m). The quaternary treatment tank is connected to the sludge tank and uses natural cooling to freeze. When the ice thickness reaches 50cm, the ice in the primary, secondary, tertiary and quaternary treatment pools will be moved into the ice storage pool (with an area of 6 mu and a height of 10m). The wastewater will then be discharged into the next treatment pool in turn. The treatment order is: the wastewater in the quaternary treatment pool will be discharged into the sludge pool, the wastewater in the tertiary treatment pool will be discharged into the quaternary treatment pool, the wastewater in the secondary treatment pool will be discharged into the tertiary treatment pool, and the wastewater in the primary treatment pool will be discharged into the secondary treatment pool, and the operation will be repeated. Step 3: After the temperature rises, the ecological floating island technology is used to treat the mixed sewage in the sludge pool, and the ice in the ice storage pool is melted and used for rural landscaping and agricultural irrigation.
[0021] Example 2: This example discloses a method for preparing a composite adsorption material, comprising the following steps: Q1: Add 1 g of sodium hyaluronate to 120 mL of 0.1 mol / L MES buffer at pH 5.5, stir and mix, then add 0.62 g of 4-(4,6-dimethoxy-1,3,5-triazine-2-yl)-4-methylmorpholine chloride, continue stirring for 30 min, then add 0.14 g of methylaminoacetaldehyde dimethyl acetal, heat and stir at 60°C for 24 h, condense and reflux, and after the reflux, dialyze with a molecular cutoff of 14 kDa using a dialysis bag. First, dialyze with 0.1 mol / L sodium chloride solution for 2 days, then dialyze with deionized water for 1 day, and lyophilize to obtain an intermediate. Q2: Add 1 g of the intermediate to 100 mL of deionized water, hydrolyze with 0.2 mol / L hydrochloric acid solution for 2 days, adjust the pH to 4 with 0.1 mol / L sodium bicarbonate solution, let stand for 12 hours, and dialyze with deionized water for 3 days to obtain modified sodium hyaluronate; Q3: Add 2.4 g of polyvinyl alcohol to 26.7 mL of deionized water, heat and stir at 90°C to dissolve to obtain a polyvinyl alcohol solution, add 1 g of modified sodium hyaluronate to 100 mL of deionized water, stir and dissolve to obtain a modified sodium hyaluronate solution, add 1.8 g of polyacrylic acid to 24.8 mL of deionized water, stir and mix evenly to obtain a polyacrylic acid solution, then, mix 30 g of polyvinyl alcohol solution, 2 g of modified sodium hyaluronate solution and 28 g of polyacrylic acid solution to obtain an electrospinning solution, and obtain a nanomembrane through electrospinning technology. Heat the reaction at 115°C for 8 h, wash with distilled water for 48 h, and freeze-dry to obtain a composite adsorption material.
[0022] See Figure 1 As shown, this embodiment provides a method for treating rural sewage by using natural freezing, comprising the following steps: Step 1: The collected rural sewage is passed through a screen with a grid pitch of ≤20mm and flows into a grit chamber for 30 minutes. Lime or ferrous sulfate is added to adjust the pH to 7. Composite adsorption material is added for adsorption treatment for 90 minutes. After the adsorption treatment is completed, the composite adsorption material is removed to obtain pretreated rural sewage. Step 2: Add the pre-treated rural sewage to the water storage tank (area of 6 mu, height of 6m, when the temperature of the water storage tank is below 0℃, the water body will not freeze), and then discharge it into the primary treatment tank (area of 54 mu, height of 0.6m), secondary treatment tank (area of 9 mu, height of 0.6m), tertiary treatment tank (area of 1.5 mu, height of 0.6m) and quaternary treatment tank (area of 0.25 mu, height of 0.6m). The quaternary treatment tank is connected to the sludge tank and uses natural cooling to freeze. When the ice thickness reaches 50cm, the ice in the primary, secondary, tertiary and quaternary treatment pools will be moved into the ice storage pool (with an area of 6 mu and a height of 10m). The wastewater will then be discharged into the next treatment pool in turn. The treatment order is: the wastewater in the quaternary treatment pool will be discharged into the sludge pool, the wastewater in the tertiary treatment pool will be discharged into the quaternary treatment pool, the wastewater in the secondary treatment pool will be discharged into the tertiary treatment pool, and the wastewater in the primary treatment pool will be discharged into the secondary treatment pool, and the operation will be repeated. Step 3: After the temperature rises, the ecological floating island technology is used to treat the mixed sewage in the sludge pool, and the ice in the ice storage pool is melted and used for rural landscaping and agricultural irrigation.
[0023] Example 3: This example discloses a method for preparing a composite adsorption material, comprising the following steps: Q1: Add 1.5 g of sodium hyaluronate to 200 mL of 0.1 mol / L MES buffer at pH 5.5, stir and mix, then add 0.95 g of 4-(4,6-dimethoxy-1,3,5-triazine-2-yl)-4-methylmorpholine chloride, continue stirring for 30 min, then add 0.22 g of methylaminoacetaldehyde dimethyl acetal, heat and stir at 60°C for 24 h, condense and reflux, and after reflux, dialyze with a molecular cutoff of 14 kDa using a dialysis bag. First, dialyze with 0.1 mol / L sodium chloride solution for 2 days, then dialyze with deionized water for 1 day, and lyophilize to obtain an intermediate. Q2: Add 1.8 g of the intermediate to 180 mL of deionized water, hydrolyze with 0.2 mol / L hydrochloric acid solution for 2 days, adjust the pH to 4 with 0.1 mol / L sodium bicarbonate solution, let stand for 12 hours, and dialyze with deionized water for 3 days to obtain modified sodium hyaluronate; Q3: Add 2.4 g of polyvinyl alcohol to 26.7 mL of deionized water, heat and stir at 90°C to dissolve to obtain a polyvinyl alcohol solution, add 1 g of modified sodium hyaluronate to 100 mL of deionized water, stir and dissolve to obtain a modified sodium hyaluronate solution, add 1.8 g of polyacrylic acid to 24.8 mL of deionized water, stir and mix evenly to obtain a polyacrylic acid solution, then, mix 45 g of polyvinyl alcohol solution, 3 g of modified sodium hyaluronate solution and 20 g of polyacrylic acid solution to obtain an electrospinning solution, and obtain a nanomembrane through electrospinning technology. Heat the reaction at 115°C for 8 h, wash with distilled water for 48 h, and freeze-dry to obtain a composite adsorption material.
[0024] See Figure 1 As shown, this embodiment provides a method for treating rural sewage by using natural freezing, comprising the following steps: Step 1: The collected rural sewage is passed through a screen with a grid pitch of ≤20mm and flows into a grit chamber for 30 minutes. Lime or ferrous sulfate is added to adjust the pH to 7. Composite adsorption material is added for adsorption treatment for 90 minutes. After the adsorption treatment is completed, the composite adsorption material is removed to obtain pretreated rural sewage. Step 2: Add the pre-treated rural sewage to the water storage tank (area of 6 mu, height of 6m, when the temperature of the water storage tank is below 0℃, the water body will not freeze), and then discharge it into the primary treatment tank (area of 54 mu, height of 0.6m), secondary treatment tank (area of 9 mu, height of 0.6m), tertiary treatment tank (area of 1.5 mu, height of 0.6m) and quaternary treatment tank (area of 0.25 mu, height of 0.6m). The quaternary treatment tank is connected to the sludge tank and uses natural cooling to freeze. When the ice thickness reaches 50cm, the ice in the primary, secondary, tertiary and quaternary treatment pools will be moved into the ice storage pool (with an area of 6 mu and a height of 10m). The wastewater will then be discharged into the next treatment pool in turn. The treatment order is: the wastewater in the quaternary treatment pool will be discharged into the sludge pool, the wastewater in the tertiary treatment pool will be discharged into the quaternary treatment pool, the wastewater in the secondary treatment pool will be discharged into the tertiary treatment pool, and the wastewater in the primary treatment pool will be discharged into the secondary treatment pool, and the operation will be repeated. Step 3: After the temperature rises, the ecological floating island technology is used to treat the mixed sewage in the sludge pool, and the ice in the ice storage pool is melted and used for rural landscaping and agricultural irrigation.
[0025] Example 4: This example discloses a method for preparing a composite adsorption material, comprising the following steps: Q1: Add 1.1 g of sodium hyaluronate to 140 mL of 0.1 mol / L MES buffer at pH 5.5, stir and mix, then add 0.67 g of 4-(4,6-dimethoxy-1,3,5-triazine-2-yl)-4-methylmorpholine chloride, continue stirring for 30 min, then add 0.16 g of methylaminoacetaldehyde dimethyl acetal, heat and stir at 60°C for 24 h, condense and reflux, and after reflux, dialyze with a molecular cutoff of 14 kDa using a dialysis bag. First, dialyze with 0.1 mol / L sodium chloride solution for 2 days, then dialyze with deionized water for 1 day, and lyophilize to obtain an intermediate. Q2: Add 1.2 g of the intermediate to 160 mL of deionized water, hydrolyze with 0.2 mol / L hydrochloric acid solution for 2 days, adjust the pH to 4 with 0.1 mol / L sodium bicarbonate solution, let stand for 12 hours, and dialyze with deionized water for 3 days to obtain modified sodium hyaluronate; Q3: Add 2.4 g of polyvinyl alcohol to 26.7 mL of deionized water, heat and stir at 90°C to dissolve to obtain a polyvinyl alcohol solution, add 1 g of modified sodium hyaluronate to 100 mL of deionized water, stir and dissolve to obtain a modified sodium hyaluronate solution, add 1.8 g of polyacrylic acid to 24.8 mL of deionized water, stir and mix evenly to obtain a polyacrylic acid solution, then, mix 32 g of polyvinyl alcohol solution, 2.2 g of modified sodium hyaluronate solution and 22 g of polyacrylic acid solution evenly to obtain an electrospinning solution, and obtain a nanomembrane through electrospinning technology. Heat the reaction at 115°C for 8 h, wash with distilled water for 48 h, and freeze-dry to obtain a composite adsorption material.
[0026] See Figure 1 As shown, this embodiment provides a method for treating rural sewage by using natural freezing, comprising the following steps: Step 1: The collected rural sewage is passed through a screen with a grid pitch of ≤20mm and flows into a grit chamber for 30 minutes. Lime or ferrous sulfate is added to adjust the pH to 7. Composite adsorption material is added for adsorption treatment for 90 minutes. After the adsorption treatment is completed, the composite adsorption material is removed to obtain pretreated rural sewage. Step 2: Add the pre-treated rural sewage to the water storage tank (area of 6 mu, height of 6m, when the temperature of the water storage tank is below 0℃, the water body will not freeze), and then discharge it into the primary treatment tank (area of 54 mu, height of 0.6m), secondary treatment tank (area of 9 mu, height of 0.6m), tertiary treatment tank (area of 1.5 mu, height of 0.6m) and quaternary treatment tank (area of 0.25 mu, height of 0.6m). The quaternary treatment tank is connected to the sludge tank and uses natural cooling to freeze. When the ice thickness reaches 50cm, the ice in the primary, secondary, tertiary and quaternary treatment pools will be moved into the ice storage pool (with an area of 6 mu and a height of 10m). The wastewater will then be discharged into the next treatment pool in turn. The treatment order is: the wastewater in the quaternary treatment pool will be discharged into the sludge pool, the wastewater in the tertiary treatment pool will be discharged into the quaternary treatment pool, the wastewater in the secondary treatment pool will be discharged into the tertiary treatment pool, and the wastewater in the primary treatment pool will be discharged into the secondary treatment pool, and the operation will be repeated. Step 3: After the temperature rises, the ecological floating island technology is used to treat the mixed sewage in the sludge pool, and the ice in the ice storage pool is melted and used for rural landscaping and agricultural irrigation.
[0027] Example 5: This example discloses a method for preparing a composite adsorption material, comprising the following steps: Q1: Add 1.4 g of sodium hyaluronate to 180 mL of 0.1 mol / L, pH 5.5 MES buffer, stir to mix, then add 0.83 g of 4-(4,6-dimethoxy-1,3,5-triazine-2-yl)-4-methylmorpholine chloride, continue stirring for 30 min, then add 0.2 g of methylaminoacetaldehyde dimethyl acetal, heat and stir at 60°C for 24 h, condense and reflux, and after the reflux, dialyze with a molecular cutoff of 14 kDa using a dialysis bag. First, dialyze with 0.1 mol / L sodium chloride solution for 2 days, then dialyze with deionized water for 1 day, and lyophilize to obtain an intermediate; Q2: Add 1.6 g of the intermediate to 120 mL of deionized water, hydrolyze with 0.2 mol / L hydrochloric acid solution for 2 days, adjust the pH to 4 with 0.1 mol / L sodium bicarbonate solution, let stand for 12 hours, and dialyze with deionized water for 3 days to obtain modified sodium hyaluronate; Q3: Add 2.4 g of polyvinyl alcohol to 26.7 mL of deionized water, heat and stir at 90°C to dissolve to obtain a polyvinyl alcohol solution, add 1 g of modified sodium hyaluronate to 100 mL of deionized water, stir and dissolve to obtain a modified sodium hyaluronate solution, add 1.8 g of polyacrylic acid to 24.8 mL of deionized water, stir and mix evenly to obtain a polyacrylic acid solution, then, mix 42 g of polyvinyl alcohol solution, 2.8 g of modified sodium hyaluronate solution and 26 g of polyacrylic acid solution evenly to obtain an electrospinning solution, and obtain a nanomembrane through electrospinning technology. Heat the reaction at 115°C for 8 hours, wash with distilled water for 48 hours, and freeze-dry to obtain a composite adsorption material.
[0028] See Figure 1 As shown, this embodiment provides a method for treating rural sewage by using natural freezing, comprising the following steps: Step 1: The collected rural sewage is passed through a screen with a grid pitch of ≤20mm and flows into a grit chamber for 30 minutes. Lime or ferrous sulfate is added to adjust the pH to 7. Composite adsorption material is added for adsorption treatment for 90 minutes. After the adsorption treatment is completed, the composite adsorption material is removed to obtain pretreated rural sewage. Step 2: Add the pre-treated rural sewage to the water storage tank (area of 6 mu, height of 6m, when the temperature of the water storage tank is below 0℃, the water body will not freeze), and then discharge it into the primary treatment tank (area of 54 mu, height of 0.6m), secondary treatment tank (area of 9 mu, height of 0.6m), tertiary treatment tank (area of 1.5 mu, height of 0.6m) and quaternary treatment tank (area of 0.25 mu, height of 0.6m). The quaternary treatment tank is connected to the sludge tank and uses natural cooling to freeze. When the ice thickness reaches 50cm, the ice in the primary, secondary, tertiary and quaternary treatment pools will be moved into the ice storage pool (with an area of 6 mu and a height of 10m). The wastewater will then be discharged into the next treatment pool in turn. The treatment order is: the wastewater in the quaternary treatment pool will be discharged into the sludge pool, the wastewater in the tertiary treatment pool will be discharged into the quaternary treatment pool, the wastewater in the secondary treatment pool will be discharged into the tertiary treatment pool, and the wastewater in the primary treatment pool will be discharged into the secondary treatment pool, and the operation will be repeated. Step 3: After the temperature rises, the ecological floating island technology is used to treat the mixed sewage in the sludge pool, and the ice in the ice storage pool is melted and used for rural landscaping and agricultural irrigation.
[0029] Based on the climatic conditions of Inner Mongolia, rural sewage was treated using the method of Example 1. The test period was from November 1 to April 1 of the following year. COD, TN, and TP in the water storage tank, primary treatment tank, secondary treatment tank, tertiary treatment tank, quaternary treatment tank, and ice storage tank were tested. The test results are shown in Table 1: Table 1 Concentrations and reduction rates of COD, TN, and TP in water and ice storage tanks
[0030] Table 2 Total amount and concentration of pollutants in ice at various treatment pools from November 1 to January 15 of the following year
[0031] Table 3 Total amount and concentration of pollutants in water from various treatment pools from November 1 to January 15 of the following year
[0032] Table 4 Total amount and concentration of pollutants in ice at each treatment pool from 1.15 to 4.1
[0033] Table 5 Total amount and concentration of pollutants in water from treatment pools at all levels during the period from 1.15 to 4.1
[0034] It can be seen from the data in Table 1-5 that the use of natural freezing to treat rural sewage can simply and effectively remove COD, TN and TP in sewage. Table 2-5 shows the total amount of COD, TN and TP before treatment in different treatment pools and the concentrations of COD, TN and TP after treatment in different treatment pools between 11.1 and 1.15 of the following year and 1.15 and 4.1. It can be found from the data in Table 1-5 that after treatment, the content of COD, TN and TP in water and ice is reduced, indicating that this treatment method can effectively remove pollutants in rural sewage, is easy to operate and easy to promote.
[0035] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.
[0036] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.
Claims
1. A method for treating rural sewage by utilizing natural freezing, characterized in that: The following steps are involved: Step 1: The collected rural sewage is passed through a screen and flows into a grit chamber for sedimentation, the pH is adjusted, and composite adsorption materials are added for adsorption treatment. After the adsorption treatment is completed, the composite adsorption materials are removed to obtain pretreated rural sewage; Step 2: Add pretreated rural sewage to the water storage tank, and then discharge it into the primary treatment tank, secondary treatment tank, tertiary treatment tank and quaternary treatment tank in sequence. The quaternary treatment tank is connected to the sludge tank. Natural cooling and freezing are used to move the ice in the primary treatment tank, secondary treatment tank, tertiary treatment tank and quaternary treatment tank into the ice storage tank. The sewage is then discharged into the next treatment tank in sequence, and the operation is repeated. Step 3: After the temperature rises, the ecological floating island technology is used to treat the mixed sewage in the sludge pool, and the ice in the ice storage pool is melted and used for rural landscaping and agricultural irrigation.
2. The method for treating rural sewage by utilizing natural freezing according to claim 1, characterized in that: In the step 1, the grid pitch is ≤20 mm, the precipitation time is ≥30 min, lime or ferrous sulfate is added to adjust the pH to 6-8, and the adsorption treatment time is 60-90 min.
3. The method for treating rural sewage by utilizing natural freezing according to claim 1, characterized in that: In step 1, the preparation method of the composite adsorption material comprises the following steps: Q1: Sodium hyaluronate was added to MES buffer and stirred to mix. Then, 4-(4,6-dimethoxy-1,3,5-triazine-2-yl)-4-methylmorpholine chloride was added and stirring was continued. Then, methylaminoacetaldehyde dimethyl acetal was added. The mixture was heated with stirring and refluxed under condensation. After the reflux period, the mixture was dialyzed and freeze-dried to obtain an intermediate. Q2: Add the intermediate to deionized water, hydrolyze with acid, adjust the pH, let stand, and dialyze to obtain modified sodium hyaluronate; Q3: Add polyvinyl alcohol to deionized water, heat and stir to dissolve to obtain a polyvinyl alcohol solution, add modified sodium hyaluronate to deionized water, stir to dissolve to obtain a modified sodium hyaluronate solution, add polyacrylic acid to deionized water, stir and mix evenly to obtain a polyacrylic acid solution, then, mix the polyvinyl alcohol solution, modified sodium hyaluronate solution and polyacrylic acid solution evenly to obtain an electrospinning solution, obtain a nanofilm through electrospinning technology, heat to react, wash, and freeze-dry to obtain a composite adsorption material.
4. The method for treating rural sewage by utilizing natural freezing according to claim 3, characterized in that: In Q1, the dosage ratio of sodium hyaluronate, MES buffer, 4-(4,6-dimethoxy-1,3,5-triazine-2-yl)-4-methylmorpholine chloride and methylaminoacetaldehyde dimethyl acetal is (1-1.5) g: (120-200) mL: (0.62-0.95) g: (0.14-0.22) g, the concentration of MES buffer is 0.1 mol / L, pH=5.5, the stirring time is continued for 15-30 min, the heating and stirring temperature is 60-65° C., and the heating time is 20-24 h. During the dialysis process, the molecular retention capacity of the dialysis bag is 14 kDa. The product is first dialyzed with 0.1 mol / L sodium chloride solution for 2 days, and then dialyzed with deionized water for 1 day.
5. The method for treating rural sewage by utilizing natural freezing according to claim 3, characterized in that: In Q2, the ratio of the intermediate to deionized water is (1-1.8) g: (100-180) mL. The product is hydrolyzed with 0.2 mol / L hydrochloric acid solution for 2 days, and the pH is adjusted to 3.8-4.2 with 0.1 mol / L sodium bicarbonate solution. The product is allowed to stand for 10-12 hours and then dialyzed with deionized water for 2-3 days.
6. The method for treating rural sewage by utilizing natural freezing according to claim 3, characterized in that: In Q3, the heating and stirring temperature is 88-92°C, the usage ratio of polyvinyl alcohol solution, modified sodium hyaluronate solution and polyacrylic acid solution is (30-45) g: (2-3) g: (20-28) g, the heating reaction temperature is 110-125°C, the reaction time is 6-8 hours, and the product is washed with distilled water for 48-52 hours.
7. The method for treating rural sewage by utilizing natural freezing according to claim 1, characterized in that: In the step 2, the water storage tank has an area of 6 mu and a height of 6 m. When the temperature of the water storage tank is below 0°C, the water does not freeze. The area of the first-level treatment tank is 54 mu and the height is 0.6 m. The area of the second-level treatment tank is 9 mu and the height is 0.6 m. The area of the third-level treatment tank is 1.5 mu and the height is 0.6 m. The area of the fourth-level treatment tank is 0.25 mu and the height is 0.6 m. The area of the ice storage tank is 6 mu and the height is 10 m. Cement columns with a spacing of 2 m and a height of 0.1 m are installed in the first to fourth-level treatment tanks.
8. The method for treating rural sewage by utilizing natural freezing according to claim 1, characterized in that: In the step 2, when the ice body is frozen to a thickness of 50 cm, the ice body is removed to the ice storage tank, and the sewage is discharged into the next-level treatment tank in sequence. The treatment order is: the sewage in the fourth-level treatment tank is discharged into the sludge tank, the sewage in the third-level treatment tank is discharged into the fourth-level treatment tank, the sewage in the second-level treatment tank is discharged into the third-level treatment tank, and the sewage in the first-level treatment tank is discharged into the second-level treatment tank.
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Patent Citations
Double metal oxide-hyperbranched polymer adsorbent and preparation method thereof
CN110756178A