In-situ grading preparation method of high-molecular water-feeding natural biopolymer

Abstract

The invention discloses an in-situ grading preparation method of a high-molecular feedwater natural biopolymer, and belongs to the technical field of feedwater treatment and pollution removal. The method comprises the following steps: carrying out enrichment, cleaning, separation, conditioning, concentration and other treatments and component analysis on water of each related treatment unit by adopting an ultrafiltration membrane, and respectively carrying out in-situ graded preparation on the water supply natural biopolymer in a dissolved state and a non-dissolved state in an enrichment stage and a separation stage, the preparation process is performed in situ in a water supply treatment plant; the method comprises the following steps: enriching and concentrating by adopting an external pressure type hollow fiber ultrafiltration membrane of which the pore diameter is less than 0.05 mu m, and conditioning the non-dissolved feed water natural biopolymer by adopting physical or chemical conditioning methods such as heating, hydraulic stirring, gas-water mixed cleaning, ultrasonic wave, electrolyte, acid-base, oxidant and the like; according to the invention, resource recovery and utilization can be carried out on the water supply natural biopolymer generated by microbial metabolism in the water supply treatment process flow.

Description

Technical Field

[0001] The present invention belongs to the technical fields of water treatment processes and pollution removal technologies, and particularly relates to an in-situ hierarchical preparation method for a polymer water supply natural biopolymer. Background Art

[0002] Most water treatment processes require technical measures such as pretreatment, enhanced conventional treatment, and advanced treatment to improve the removal effects of various pollutants. Among them, the coagulation process is the most critical unit, which directly affects the pollution removal efficiency of subsequent treatment units. The enhanced coagulation technology can significantly improve the removal efficiency of various pollutants in water. Among them, the optimization of the types and properties of coagulants, flocculants, and coagulant aids is the main means of enhanced coagulation. High-molecular flocculants can strengthen the adsorption bridging and enmeshment sweeping effects, significantly improve the sedimentation characteristics of flocs, and increase the removal efficiency of various pollutants. However, the large addition of flocculants will increase the chemical components in water and the safety risks. Natural flocculants and bioflocculants have the characteristics of good flocculation effect, environmental friendliness, biodegradability, and non-toxicity, and can also significantly improve the removal effects of pollutants such as particulate matter, dissolved organic matter, and heavy metals. In recent years, the research and application of green water treatment agents represented by bioflocculants have received great attention.

[0003] Extracellular polymeric substances are important matrices and components of bioflocculants, and the prepared bioflocculants have been applied in the environmental and water treatment fields. The existing bioflocculants are mainly prepared by specially cultivating, separating, and preparing extracellular polymeric substances and other metabolites produced by artificially cultivated special strains. The preparation process is complex, the productization is difficult, the cost is high, and it is difficult to be applied on a large scale.

[0004] During the water treatment process, a large amount of microorganisms and their metabolites will be generated and aggregated in the biological treatment unit during long-term operation. The natural biopolymers formed by these microbial metabolites also have a coagulation aid effect and function similar to bioflocculants. This is very different from the previous understanding of water treatment and pollution removal, and is also completely different from the way to remove these natural biopolymers during the water treatment process. The collection, separation, extraction, preparation of natural biopolymers generated during the water treatment process, and their reuse in the coagulation process of water treatment are emerging research directions that have received attention in the industry in recent years. However, the physicochemical properties, collection, extraction, conditioning, enrichment, preparation methods, and processes of natural biopolymers generated during the water treatment process are still lacking. Summary of the Invention

[0005] The present invention provides an in-situ fractionation preparation method for a polymer natural biopolymer. An ultrafiltration membrane is used to enrich, extract, and concentrate the natural biopolymer formed in the treatment unit with biological purification function in the water treatment process flow. At the same time, the properties of the obtained polymer natural biopolymer are conditioned to realize the resource utilization of the polymer natural biopolymer in the water treatment process.

[0006] To achieve the above object, the present invention adopts the following technical solution: An in-situ fractionation preparation method for a polymer natural biopolymer in water supply. The fractionation preparation process mainly includes processes such as collection, precipitation, enrichment, cleaning, separation, and conditioning, and includes the following steps:

[0007] Step 1: Collect the water from each relevant treatment unit in the water treatment process flow, and use an ultrafiltration membrane (the filtered clear water is discarded) for concentration and enrichment. Then, separate the liquid and solid matter in the enriched liquid with filter paper or a microfiltration membrane to obtain a dissolved enriched liquid A (i.e., the liquid in the enriched liquid) and a non-dissolved enriched precipitate B (i.e., the solid matter in the enriched liquid);

[0008] Step 2: Perform component analysis on the dissolved enriched liquid A obtained after enrichment in Step 1. For the dissolved enriched liquid A that meets Standard I, use an ultrafiltration membrane for enrichment; for the dissolved enriched liquid A that does not meet the standard, perform conditioning and component analysis until it meets Standard I, and then use an ultrafiltration membrane to enrich the dissolved enriched liquid A that meets Standard I to obtain a first enriched liquid (i.e., the enriched dissolved enriched liquid A that meets Standard I);

[0009] Step 3: Perform component extraction on the non-dissolved enriched precipitate B obtained after enrichment in Step 1 to obtain a dissolved component C of the non-dissolved enriched precipitate. Perform component analysis on the obtained dissolved component C of the non-dissolved enriched precipitate. For the dissolved component C of the non-dissolved enriched precipitate that meets Standard I, use an ultrafiltration membrane for enrichment; for the dissolved component C of the non-dissolved enriched precipitate that does not meet Standard I, perform conditioning and component analysis until it meets Standard I, and then use an ultrafiltration membrane to enrich the dissolved component C of the non-dissolved enriched precipitate that meets Standard I to obtain a second enriched liquid (i.e., the enriched dissolved component C of the non-dissolved enriched precipitate that meets Standard I).

[0010] Step 4: When the transmembrane pressure difference of the ultrafiltration membrane in Step 1 is greater than 5 m or the membrane flux is less than 5 L / h·m 2 , clean the ultrafiltration membrane to obtain a cleaning liquid. Use an ultrafiltration membrane to concentrate and enrich the obtained cleaning liquid, and then separate the liquid and solid matter in the enriched cleaning liquid with filter paper or a microfiltration membrane to also obtain a dissolved cleaning liquid D (i.e., the liquid in the enriched cleaning liquid) and a non-dissolved cleaning precipitate E (i.e., the solid matter in the enriched cleaning liquid);

[0011] Step 5: Analyze the components of the dissolved cleaning liquid D obtained in Step 4. For the dissolved cleaning liquid D that meets Standard Ⅰ, concentrate and enrich it using an ultrafiltration membrane. For the dissolved cleaning liquid D that does not meet Standard Ⅰ, condition it and analyze its components until it meets Standard Ⅰ, and then concentrate and enrich the dissolved cleaning liquid D that meets Standard Ⅰ using an ultrafiltration membrane to obtain the third enriched liquid (i.e., the enriched dissolved cleaning liquid D that meets Standard Ⅰ).

[0012] Step 6: Extract the components of the non-dissolved cleaning precipitate E obtained in Step 4 to obtain the dissolved components F of the non-dissolved cleaning precipitate. Analyze the components of the obtained dissolved components F of the non-dissolved cleaning precipitate. For the dissolved components F of the non-dissolved cleaning precipitate that meets Standard Ⅰ, enrich it using an ultrafiltration membrane; for the dissolved components F of the non-dissolved cleaning precipitate that does not meet Standard Ⅰ, condition it and analyze its components until it meets Standard Ⅰ, and then enrich the dissolved components F of the non-dissolved cleaning precipitate that meets Standard Ⅰ using an ultrafiltration membrane to obtain the fourth enriched liquid (i.e., the enriched dissolved components F of the non-dissolved cleaning precipitate that meets Standard Ⅰ).

[0013] Step 7: Analyze the components of the first enriched liquid, the second enriched liquid, the third enriched liquid, and the fourth enriched liquid. Enrich the first enriched liquid, the second enriched liquid, the third enriched liquid, or the fourth enriched liquid that does not meet Standard Ⅱ until it meets Standard Ⅱ, and then mix the first enriched liquid, the second enriched liquid, the third enriched liquid, and the fourth enriched liquid that meet Standard Ⅱ to obtain the high-molecular water supply natural biopolymer G.

[0014] The water treatment process flow in Step 1 includes a conventional treatment process flow composed of conventional coagulation, sedimentation, filtration and other units; each relevant treatment unit in the water treatment process flow includes a pretreatment unit and a deep treatment unit, including but not limited to a coagulation-sedimentation unit, a biological treatment unit, and a membrane filtration unit; the water in each relevant treatment unit includes the sludge discharged from the biological pretreatment unit, the sludge discharged from the sedimentation tank and the clarifier, the backwash water of the filter, the backwash water of various packing biological filters such as activated carbon, and the concentrated water discharged from membrane filtration units such as microfiltration, ultrafiltration, and nanofiltration and / or the membrane pool water, etc., including the well water and the storage pool water that collect the drainage of the above-mentioned treatment units.

[0015] The collection methods in Step 1 include but are not limited to direct extraction, siphon extraction, collection from the enriched liquid collection port, etc., as shown in ① in Figure 1 as shown in

[0016] The component extraction methods in Step 3 include but are not limited to one or several of the following: adding water for hydraulic stirring, heating, separation (including filtration with filter paper or microfiltration membrane, centrifugation, etc.), ultrasonic treatment, acid-base extraction, etc.

[0017] The ultrafiltration membranes in Step 1, Step 2, Step 3, Step 4, Step 5, and Step 6 are external pressure type hollow fiber ultrafiltration membranes with a pore size not greater than 0.05 μm and a membrane flux not greater than 20 L / h·m 2 .

[0018] The standard I in Step 1, Step 2, Step 3, Step 4, Step 5, and Step 6 is as follows: The phenol-sulfuric acid method is used to measure polysaccharides and the Lowry method is used to measure proteins. The sum of proteins and polysaccharides, that is, the total amount of biopolymers in the feed water, is not less than 100 mg / L, and the proportion of polysaccharides is not less than 40%. As Figure 2 , 3 , as shown in Figure 4, the concentrated liquid that does not meet the standard I cannot achieve a satisfactory coagulation aid and turbidity removal effect.

[0019] The standard II in Step 7 is as follows: The phenol-sulfuric acid method is used to measure polysaccharides and the Lowry method is used to measure proteins. The sum of proteins and polysaccharides, that is, the total amount of biopolymers in the feed water, is not less than 2500 mg / L, and the proportion of polysaccharides is not less than 40%.

[0020] The specific method of enrichment by ultrafiltration membrane in Step 1, Step 2, Step 3, Step 4, Step 5, Step 6, and Step 7 is as follows: Filtration is carried out using an external pressure type ultrafiltration membrane, and the filtered water is discarded. The concentrated liquid is the concentrated water produced by the external pressure type ultrafiltration membrane, that is, the water containing high-concentration organic matter that does not pass through the ultrafiltration membrane. The specific degree of enrichment is based on whether the concentrated liquid meets the standard I or standard II.

[0021] The conditioning methods in Step 2, Step 3, Step 5, and Step 6 include: physical methods, chemical methods, and physical-chemical combined methods. Physical methods such as ultrasonic waves, heating, and hydraulic stirring, chemical methods such as adding various acids, bases, inorganic salts, electrolytes, oxidants, etc., and physical-chemical combined methods such as ultrasonic treatment after acidification (such as acidification with HCl) or alkalization (such as alkalization with NaOH).

[0022] The conditioning selection methods for Step 2, Step 3, Step 5, and Step 6 are further as follows: For the dissolved enriched liquid A, the dissolved components C of the non-dissolved enriched precipitate, the dissolved cleaning liquid D, and the dissolved components F of the non-dissolved cleaning precipitate with a total feed bio-polymer amount higher than 100 mg / L but a polysaccharide proportion lower than 40%, physical methods are used for conditioning, such as ultrasonic waves, heating, hydraulic stirring, etc.; for the dissolved enriched liquid A, the dissolved components C of the non-dissolved enriched precipitate, the dissolved cleaning liquid D, and the dissolved components F of the non-dissolved cleaning precipitate with a total feed bio-polymer amount lower than 100 mg / L but a polysaccharide proportion higher than 40%, chemical methods are used for conditioning after enrichment, such as adding various acids and bases, inorganic salts, electrolytes, oxidants, etc.; for the dissolved enriched liquid A, the dissolved components C of the non-dissolved enriched precipitate, the dissolved cleaning liquid D, and the dissolved components F of the non-dissolved cleaning precipitate with a total feed bio-polymer amount lower than 100 mg / L and a polysaccharide proportion lower than 40%, combined physical and chemical methods are used for conditioning after enrichment, such as ultrasonic waves after acidification or alkalization.

[0023] The cleaning in Step 4 includes but is not limited to: 1. Repeatedly cleaning with a certain amount of clear water or a gas-water mixture; 2. Repeatedly cleaning by soaking with a certain amount of electrolyte solution with a concentration not higher than 0.5% in combination with a gas-water mixture; The cleaning methods include but are not limited to: 1. Cross-flow cleaning on the outer side of the membrane, 2. Forward and reverse flow cleaning on the inner side of the membrane, etc. The cleaning liquid collection methods include but are not limited to direct extraction, siphon extraction, and collection from the enriched liquid collection port, as shown in ② in Figure 1 as shown in

[0024] The separation methods in Step 1 and Step 5 include but are not limited to filtration with quantitative filter paper and suction filtration with a 0.45 μm microfiltration membrane.

[0025] The high-molecular feed natural bio-polymer G in Step 7 is composed of one or more mixtures of the first enriched liquid, the second enriched liquid, the third enriched liquid, and the fourth enriched liquid. When the enriched liquid does not meet Standard II, it should not be mixed into the high-molecular feed natural bio-polymer G.

[0026] The high-molecular feed natural bio-polymer G obtained by the present invention is directly added to water as a coagulant aid to reduce the dosage of coagulants (such as polyaluminum chloride PAC); it can be directly recycled.

[0027] The remarkable advantages of the present invention are:

[0028] In the long - term running water treatment process flow, treatment units with biological purification functions will generate and accumulate a large number of microorganisms and their metabolites. The natural biopolymers formed by these microbial metabolites have coagulation - aiding effects and functions similar to those of bio - flocculants. The obtained natural biopolymers in water supply are environmentally friendly, biodegradable, and non - toxic. Based on the coagulation and coagulation - aiding functions of the above - mentioned natural biopolymers in water supply, the present invention provides a method for in - situ preparation of high - molecular natural biopolymers G in the water treatment process flow, and proposes in - situ preparation processes and methods for the collection, extraction, conditioning, enrichment, and preparation of natural biopolymers in water supply. At the same time, the performance of high - molecular natural biopolymers G is conditioned, which can realize the resource recovery and utilization of high - molecular natural biopolymers in water supply. As shown by the data in Example 1 Figure 2 and the data in Example 2 Figure 3 and the data in Example 3 Figure 4 show that the high - molecular natural biopolymers that meet Standards I and II after performance conditioning have stronger coagulation - aiding and turbidity - removal performance than the dissolved - state enrichment liquid A that does not meet Standard I, the dissolved - state component C of the non - dissolved - state enrichment precipitate, the dissolved - state cleaning liquid D, and the dissolved - state component F of the non - dissolved - state cleaning precipitate without performance conditioning, under the same dosage. They can be directly reused in the coagulation process of water treatment. This method has the characteristics of simple enrichment and enrichment process, convenient operation, saving the dosage of PAC (polyaluminum chloride), and direct reuse, and is easy to be practically applied in water treatment plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the sources of the dissolved - state enrichment liquid A, non - dissolved - state enrichment precipitate B, cleaning mixture, dissolved - state cleaning liquid D, and non - dissolved - state cleaning precipitate E in Steps 1, 2, 3, 4, 5, and 6 provided by the present invention.

[0030] Figure 2 It is a data graph of the coagulation - aiding (measured by the stable flocculation index FI value), turbidity - removal (measured by the turbidity removal rate), and performance conditioning (measured by the polysaccharide ratio or viscosity value) of the high - molecular natural biopolymer G provided by the present invention, corresponding to Examples 1, 2, and 3 respectively.

[0031] Figure 3 It is a data graph of the coagulation - aiding (measured by the stable flocculation index FI value), turbidity - removal (measured by the turbidity removal rate), and performance conditioning (measured by the polysaccharide ratio or viscosity value) of the high - molecular natural biopolymer G provided by the present invention;

[0032] Figure 4 It is a data graph of the coagulation - aiding (measured by the stable flocculation index FI value), turbidity - removal (measured by the turbidity removal rate), and performance conditioning (measured by the polysaccharide ratio or viscosity value) of the high - molecular natural biopolymer G provided by the present invention. Detailed implementation manners

[0033] The following further describes the present invention in conjunction with the appended Figure 2 、 3 、4 and Examples 1, 2, and 3. These embodiments are only a part of the examples of the present invention, rather than all embodiments. The said embodiments and the accompanying drawings are only used for exemplary description of the present invention, and cannot constitute any limitation to the protection scope of the present invention. All reasonable transformations and combinations within the scope of the inventive concept of the present invention fall within the protection scope of the present invention.

[0034] Example 1

[0035] Take the backwash drainage of the ultrafiltration membrane pool for the operation of preparing biopolymers by grading. The specific implementation steps are as follows: (1) Collect the backwash suspension of the ultrafiltration membrane pool by direct extraction. Since there are many solids in the backwash suspension, let the obtained backwash suspension stand for more than 2 h for enrichment. Enrich the suspension with an ultrafiltration membrane, discard the filtered clear liquid, filter the enriched suspension with a medium-speed quantitative filter paper. The filtered clear liquid is the dissolved-state enriched liquid A, and the solids remaining on the filter paper are the non-dissolved-state enriched precipitate B.

[0036] Use the phenol-sulfuric acid method to measure polysaccharides and the Lowry method to measure proteins. Confirm that the total amount of biopolymers in the feed water of the dissolved-state enriched liquid A is 128 mg / L at this time, and the polysaccharide proportion is 31.42%; perform performance conditioning on the dissolved-state enriched liquid A under the conditions of an ultrasonic frequency of 40 kHz and an action time of 10 min to obtain a conditioning liquid. Component analysis confirms that the total amount of biopolymers in the feed water of the dissolved-state enriched liquid A is 104.19 mg / L at this time, and the polysaccharide proportion is 56.67%, meeting Standard I, to obtain the first enriched liquid.

[0037] (2) Disperse the non-dissolved-state enriched precipitate B in a 50 mL centrifuge tube, add 15 mL of deionized water and vortex for 1 min. After standing for 10 min, separate with a medium-speed quantitative filter paper. The clear liquid is the dissolved-state component C of the non-dissolved-state enriched precipitate, and the solids remaining on the filter paper are discarded. Use the phenol-sulfuric acid method to measure polysaccharides and the Lowry method to measure proteins. Confirm that the total amount of biopolymers in the feed water of the dissolved-state component C of the non-dissolved-state enriched precipitate is 114.27 mg / L at this time, and the polysaccharide proportion is 33.47%; perform performance conditioning on the dissolved-state component C of the non-dissolved-state enriched precipitate under the ultrasonic conditions of an ultrasonic frequency of 42 kHz and a duration of 14 min to obtain a conditioning liquid. Component analysis confirms that the total amount of biopolymers in the feed water of the dissolved-state component C of the non-dissolved-state enriched precipitate is 109.44 mg / L at this time, and the polysaccharide proportion is 51.43%, meeting Standard I, to obtain the second enriched liquid.

[0038] (3) It was detected that the transmembrane pressure difference of the ultrafiltration membrane in (1) exceeded 5 m, and the ultrafiltration membrane in (1) was cleaned with 0.5% NaCl solution. The cleaning solution was allowed to stand for more than 2 h, and the cleaning solution was filtered with medium-speed quantitative filter paper. The filtered clear liquid was the dissolved cleaning solution D, and the solids remaining on the filter paper were the undissolved cleaning precipitate E. The phenol-sulfuric acid method was used to measure polysaccharides, and the Lowry method was used to measure proteins. It was confirmed that the total amount of feed water biopolymers in the dissolved cleaning solution D at this time was 137.82 mg / L, and the polysaccharide proportion was 39.22%. Under the ultrasonic conditions of an ultrasonic frequency of 40 kHz and a duration of 10 min, the performance of the dissolved cleaning solution was conditioned to obtain a conditioned solution. Component analysis confirmed that the total amount of feed water biopolymers in the dissolved cleaning solution D at this time was 103.54 mg / L, and the polysaccharide proportion was 46.42%, meeting Standard I, and the third enriched solution was obtained.

[0039] (4) The undissolved cleaning precipitate E was dispersed in a 50 mL centrifuge tube, 15 mL of deionized water was added, and it was vortexed for 1 min. The uniformly mixed liquid to be extracted was centrifuged at 4000 G for 20 min, and the supernatant was taken as the dissolved component F of the undissolved cleaning precipitate. The solids in the centrifuge tube were discarded. The phenol-sulfuric acid method was used to measure polysaccharides, and the Lowry method was used to measure proteins. It was confirmed that the total amount of feed water biopolymers in the dissolved component F of the undissolved cleaning precipitate at this time was 141.67 mg / L, and the polysaccharide proportion was 33.33%. Under the ultrasonic conditions of an ultrasonic frequency of 42 kHz and a duration of 14 min, the undissolved cleaning precipitate was treated to obtain a conditioned solution. Component analysis confirmed that the total amount of feed water biopolymers in the dissolved component F of the undissolved cleaning precipitate at this time was 122.71 mg / L, and the polysaccharide proportion was 41.9%, meeting Standard I, and the fourth enriched solution was obtained.

[0040] (5) The first enriched solution, the second enriched solution, the third enriched solution, and the fourth enriched solution were mixed and enriched. At this time, small molecule substances were discarded because they passed through the ultrafiltration membrane (not described again in Examples 2 and 3). The phenol-sulfuric acid method was used to measure polysaccharides, and the Lowry method was used to measure proteins. A detection accuracy of 0 - 150 mg / L was better, so the sample was diluted 20 times for detection and then multiplied back (not described again in Examples 2 and 3). It was confirmed that the total amount of feed water biopolymers at this time was 2793.92 mg / L, and the polysaccharide proportion was 48.71%, meeting Standard II. The obtained product was the high-molecular feed water natural biopolymer G.

[0041] The obtained high-molecular-weight water supply natural biopolymer G was used for coagulation tests. The test procedure was as follows: Take a clean 1-L beaker, add coagulation test solutions I and II, add clean water to a water level of 1 L, mix rapidly at 300 rpm for 30 s, then add 30 mg / L of PAC (polyaluminum chloride), continue to mix at 300 rpm for 30 s, and then add 0.15 mg / L of the high-molecular-weight water supply natural biopolymer. After that, mix slowly at 120 rpm for 15 min, and finally let it stand for 30 min. Before and after coagulation, water samples were taken with a clean syringe to evaluate the coagulation efficiency, and the sampling position was 2 cm below the water surface. The preparation method of coagulation test solution I was as follows: Weigh 5 g of kaolin and disperse it in a clean 1-L wide-mouth bottle, and continuously stir for at least 3 days; at least 6 h before the start of the coagulation test, stop stirring. The upper-layer kaolin colloidal solution was coagulation test solution I. Coagulation test solution II was a prepared neutral humic acid solution with a concentration of at least 5 mg / L. The coagulation test parameters described in the present invention were: turbidity 32 NTU, UV 254 value of 0.822. To highlight the influence of conditioning on the coagulation aid effect of the water supply biopolymer, the coagulation test groups were as follows: 30 s after adding PAC, add blank (without adding biopolymer), add unconditioned but enriched dissolved enrichment liquid A (to ensure that the added volumes of each group were similar, so the unconditioned dissolved enrichment liquid A that did not meet standard I was also enriched by the same multiple as the conditioned dissolved enrichment liquid A that met standard I, and this will not be mentioned later), add unconditioned but enriched non-dissolved enrichment precipitate dissolved component C, add unconditioned but enriched dissolved cleaning liquid D, add unconditioned but enriched non-dissolved cleaning precipitate dissolved component F, add high-molecular-weight water supply natural biopolymer G (high-molecular-weight water supply natural biopolymer G was composed of the conditioned and enriched dissolved enrichment liquid A that met standard I, non-dissolved enrichment precipitate dissolved component C, dissolved cleaning liquid D, and non-dissolved cleaning precipitate dissolved component F that met standard II, that is, composed of the first enrichment liquid, second enrichment liquid, third enrichment liquid, and fourth enrichment liquid that met standard II). (The coagulation test procedure, grouping, and test solution preparation will not be described again in Examples 2 and 3).

[0042] The coagulation test group added with high-molecular-weight water supply natural biopolymer G had Figure 2 the highest turbidity removal rate and stable FI value within each group, as specifically shown in Figure 2 the figure, indicating that the high-molecular-weight water supply natural biopolymer G had the ability to assist in turbidity removal and coagulation.

[0043] Example 2

[0044] Take the enriched water in the ultrafiltration membrane tank and perform the operation of fractionating and extracting biopolymers. The specific implementation steps were as follows:

[0045] (1) Take the enriched water in the ultrafiltration membrane tank of the water intake plant. Use the ultrafiltration membrane to enrich the enriched water, discard the filtered clear liquid, filter the enriched liquid after enrichment with a medium-speed quantitative filter paper. The filtered clear liquid is the dissolved-state enriched liquid A, and the solid matter remaining on the filter paper is the non-dissolved-state enriched precipitate B. Use the phenol-sulfuric acid method to measure polysaccharides and the Lowry method to measure proteins. Confirm that the total amount of biopolymers in the dissolved-state enriched liquid A at this time is 87.61 mg / L, and the polysaccharide proportion is 54.97%. Conduct performance conditioning. Use the ultrafiltration membrane to enrich the dissolved-state enriched liquid A again. Adjust the pH value of the dissolved-state enriched liquid A to 11 with 1 M NaOH, and mix the dissolved-state enriched liquid A at a rotation speed of 100 - 150 rpm at room temperature for at least 20 min to obtain a conditioning liquid. Component analysis confirms that the total amount of biopolymers in the dissolved-state enriched liquid A at this time is 122.37 mg / L, and the proportion of polysaccharides is 45.28%, meeting Standard I, and obtaining the first enriched liquid.

[0046] (2) Disperse the non-dissolved-state enriched precipitate B in a 50 mL centrifuge tube, add 15 mL of deionized water and vortex for 1 min, let it stand for 10 min and separate with a medium-speed quantitative filter paper. The clear liquid is the dissolved-state component C of the non-dissolved-state enriched precipitate, and the solid matter remaining on the filter paper is discarded. Use the phenol-sulfuric acid method to measure polysaccharides and the Lowry method to measure proteins. Confirm that the total amount of biopolymers in the dissolved-state component C of the non-dissolved-state enriched precipitate at this time is 97.09 mg / L, and the polysaccharide proportion is 62.22%. Conduct performance conditioning. Use the ultrafiltration membrane to enrich the dissolved-state component C of the non-dissolved-state enriched precipitate again. Adjust the pH value of the dissolved-state component C of the non-dissolved-state enriched precipitate to 11 with 1 M NaOH, and mix the dissolved-state component C of the non-dissolved-state enriched precipitate at a rotation speed of 100 - 150 rpm at room temperature for at least 20 min to obtain a conditioning liquid. Component analysis confirms that the total amount of biopolymers in the dissolved-state component C of the non-dissolved-state enriched precipitate at this time is 142.12 mg / L, and the proportion of polysaccharides is 60.13%, meeting Standard I, and obtaining the second enriched liquid.

[0047] (3) It is detected that the transmembrane pressure difference of the ultrafiltration membrane in (1) exceeds 5 m, and the ultrafiltration membrane in (1) is cleaned with 0.5% NaCl solution. The cleaning mixture is allowed to stand for 2 h, and the suspension is filtered with medium-speed quantitative filter paper. The filtered clear liquid is the dissolved cleaning liquid D, and the solid matter remaining on the filter paper is the undissolved cleaning precipitate E. The phenol-sulfuric acid method is used to measure polysaccharides, and the Lowry method is used to measure proteins. It is confirmed that the total amount of feed water biopolymers in the dissolved cleaning liquid D at this time is 62.47 mg / L, and the polysaccharide proportion is 51.65%. Performance conditioning is carried out. The dissolved cleaning liquid D is enriched again with the ultrafiltration membrane, and the pH value of the dissolved enriched liquid D is adjusted to 11 with 1 M NaOH. The dissolved cleaning liquid D is mixed at a rotation speed of 100 - 150 rpm at room temperature for at least 20 min to obtain a conditioning liquid. Component analysis confirms that the total amount of feed water biopolymers in the dissolved cleaning liquid D at this time is 117.3 mg / L, and the proportion of polysaccharides is 41.28%, meeting Standard I, and the third enriched liquid is obtained.

[0048] (4) The undissolved cleaning precipitate E is dispersed in a 50 mL centrifuge tube, 15 mL of deionized water is added, and it is vortexed for 1 min. The uniformly mixed liquid to be extracted is centrifuged at 4000 G for 20 min, and the supernatant is taken as the dissolved component F of the undissolved cleaning precipitate. The solid matter in the centrifuge tube is discarded. The phenol-sulfuric acid method is used to measure polysaccharides, and the Lowry method is used to measure proteins. It is confirmed that the total amount of feed water biopolymers in the dissolved component F of the undissolved cleaning precipitate at this time is 82.17 mg / L, and the polysaccharide proportion is 44.27%. Performance conditioning is carried out. The dissolved component F of the undissolved cleaning precipitate is enriched again with the ultrafiltration membrane, and

[0049] the pH value of the dissolved component F of the undissolved cleaning precipitate is adjusted to 11, and the dissolved component F of the undissolved cleaning precipitate is mixed at a rotation speed of 100 - 150 rpm at room temperature for at least 20 min to obtain a conditioning liquid. Component analysis confirms that the total amount of feed water biopolymers in the dissolved component F of the undissolved cleaning precipitate at this time is 128.91 mg / L, and the proportion of polysaccharides is 42.21%, meeting Standard I, and the fourth enriched liquid is obtained.

[0050] (5) The first enriched liquid, the second enriched liquid, the third enriched liquid, and the fourth enriched liquid are mixed and enriched. The phenol-sulfuric acid method is used to measure polysaccharides, and the Lowry method is used to measure proteins. It is confirmed that the total amount of feed water biopolymers at this time is 2519.98 mg / L, and the polysaccharide proportion is 45.85%, meeting Standard II. The obtained product is the high-molecular feed water natural biopolymer G.

[0051] The obtained high-molecular feed water natural biopolymer G is used for the coagulation test. The coagulation test group added with the high-molecular feed water natural biopolymer G has Figure 3 the highest turbidity removal rate and stable FI value within each group, specifically as Figure 3As shown, it shows that the high-molecular water supply natural biopolymer G has the ability to assist in turbidity removal and coagulation.

[0052] Example 3

[0053] After backwashing the biological activated carbon filter with 0.5% NaCl solution, the operation of fractionating and extracting biopolymers is carried out. The specific implementation steps are as follows:

[0054] (1) Backwash the biological activated carbon filter with 0.5% NaCl solution, and collect the backwash suspension from the enrichment liquid collection port. Since there are many solids in the backwash suspension, let the obtained backwash suspension stand for more than 2 h for enrichment. Enrich the suspension with an ultrafiltration membrane, discard the filtered clear liquid, filter the enriched suspension with a medium-speed quantitative filter paper, the filtered clear liquid is the dissolved-state enrichment liquid A, and the solids remaining on the filter paper are the non-dissolved-state enrichment precipitate B. The phenol-sulfuric acid method is used to measure polysaccharides, and the Lowry method is used to measure proteins. It is confirmed that the total amount of water supply biopolymers in the dissolved-state enrichment liquid A at this time is 88.73 mg / L, and the polysaccharide proportion is 27.72%. Perform performance conditioning, enrich the dissolved-state enrichment liquid A again with an ultrafiltration membrane, adjust the pH value to 8.8, after ultrasonic treatment at an ultrasonic frequency of 40 kHz for 2 min, heat the dissolved-state enrichment liquid A in a water bath to 55 °C and treat it for at least 40 min to obtain a conditioning liquid. Component analysis confirms that the total amount of water supply biopolymers in the dissolved-state enrichment liquid A at this time is 110.42 mg / L, and the polysaccharide proportion is 55.78%, meeting Standard I, and obtaining the first enrichment liquid.

[0055] (2) Disperse the non-dissolved-state enrichment precipitate B in a 50 mL centrifuge tube, add 15 mL of deionized water and vortex for 1 min, let it stand for 10 min and separate with a medium-speed quantitative filter paper. The clear liquid is the dissolved-state component C of the non-dissolved-state enrichment precipitate, and the solids remaining on the filter paper are discarded. The phenol-sulfuric acid method is used to measure polysaccharides, and the Lowry method is used to measure proteins. It is confirmed that the total amount of water supply biopolymers in the dissolved-state component C of the non-dissolved-state enrichment precipitate at this time is 98.41 mg / L, and the polysaccharide proportion is 38.93%. Perform performance conditioning, enrich the dissolved-state component C of the non-dissolved-state enrichment precipitate again with an ultrafiltration membrane, adjust the pH value to 8.8, after ultrasonic treatment at an ultrasonic frequency of 40 kHz for 2 min, heat the dissolved-state component C of the non-dissolved-state enrichment precipitate in a water bath to 55 °C and treat it for at least 40 min to obtain a conditioning liquid. Component analysis confirms that the total amount of water supply biopolymers in the dissolved-state component C of the non-dissolved-state enrichment precipitate at this time is 139.73 mg / L, and the polysaccharide proportion is 43.22%, meeting Standard I, and obtaining the second enrichment liquid.

[0056] (3) It is detected that the transmembrane pressure difference of the ultrafiltration membrane in (1) exceeds 5 m, and the ultrafiltration membrane in (1) is cleaned with 0.5% NaCl solution. The cleaning solution is allowed to stand for more than 2 h, and the suspension is filtered with medium-speed quantitative filter paper. The filtered clear liquid is the dissolved cleaning solution D, and the solid matter remaining on the filter paper is the undissolved cleaning precipitate E. The phenol-sulfuric acid method is used to measure polysaccharides, and the Lowry method is used to measure proteins. It is confirmed that the total amount of feed water biopolymers in the dissolved cleaning solution D at this time is 77.27 mg / L, and the polysaccharide proportion is 33.29%. Performance conditioning is carried out. The dissolved cleaning solution D is enriched again with the ultrafiltration membrane, the pH value is adjusted to 8.8, and after ultrasonic treatment at a frequency of 40 kHz for 2 min, the dissolved cleaning solution is heated in a water bath to 55 °C and treated for at least 40 min to obtain a conditioning solution. Component analysis confirms that the total amount of feed water biopolymers in the dissolved cleaning solution D at this time is 107.48 mg / L, and the polysaccharide proportion is 47.32%, meeting Standard I, and the third enriched solution is obtained.

[0057] (4) The undissolved cleaning precipitate E is dispersed in a 50 mL centrifuge tube, 15 mL of deionized water is added and vortexed for 1 min. The uniformly mixed liquid to be extracted is centrifuged at 4000 G for 20 min, and the supernatant is taken as the dissolved component F of the undissolved cleaning precipitate. The solid matter in the centrifuge tube is discarded. The phenol-sulfuric acid method is used to measure polysaccharides, and the Lowry method is used to measure proteins. It is confirmed that the total amount of feed water biopolymers in the dissolved component F of the undissolved cleaning precipitate at this time is 89.21 mg / L, and the polysaccharide proportion is 37.26%. Performance conditioning is carried out. The dissolved component F of the undissolved cleaning precipitate is enriched again with the ultrafiltration membrane, the pH value is adjusted to 8.8, and after ultrasonic treatment at a frequency of 40 kHz for 2 min, the dissolved component F of the undissolved cleaning precipitate is heated in a water bath to 55 °C and treated for at least 40 min to obtain a conditioning solution. Component analysis confirms that the total amount of feed water biopolymers in the dissolved component F of the undissolved cleaning precipitate at this time is 131.02 mg / L, and the polysaccharide proportion is 45.29%, meeting Standard I, and the fourth enriched solution is obtained.

[0058] (5) The first enriched solution, the second enriched solution, the third enriched solution, and the fourth enriched solution are mixed and enriched. The phenol-sulfuric acid method is used to measure polysaccharides, and the Lowry method is used to measure proteins. It is confirmed that the total amount of feed water biopolymers at this time is 3391.24 mg / L, and the polysaccharide proportion is 46.75%, meeting Standard II. The obtained product is the high-molecular feed water natural biopolymer G.

[0059] The obtained high-molecular feed water natural biopolymer G is used for coagulation tests. The coagulation test group added with the high-molecular feed water natural biopolymer G has Figure 4 the highest turbidity removal rate and stable FI value within each group, specifically as Figure 4 shown, indicating that the high-molecular feed water natural biopolymer G has the ability to assist in turbidity removal and coagulation.

[0060] The above embodiments are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the concept of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, improvements and refinements made without departing from the principle of the present invention shall also be regarded as within the protection scope of the present invention.

Claims

1. An in-situ fractionation preparation method of a high molecular weight water supply natural biopolymer, characterized in that, The hierarchical preparation process mainly includes collection, precipitation, enrichment, cleaning, separation, and conditioning processes, including the following steps: Step 1: Collect the water from each relevant treatment unit in the water treatment process. Concentrate and enrich it using an ultrafiltration membrane (the filtered clear water is discarded). Then, separate the liquid and solids in the enriched liquid with filter paper or a microfiltration membrane to obtain the dissolved enriched liquid A (i.e., the liquid in the enriched liquid) and the non-dissolved enriched precipitate B (i.e., the solids in the enriched liquid). Step 2: Conduct a component analysis on the dissolved enriched liquid A obtained after enrichment in Step 1. For the dissolved enriched liquid A that meets Standard I, enrich it using an ultrafiltration membrane. For the dissolved enriched liquid A that does not meet the standard, conduct conditioning and component analysis until it meets Standard I, and then enrich the dissolved enriched liquid A that meets Standard I using an ultrafiltration membrane to obtain the first enriched liquid (i.e., the enriched dissolved enriched liquid A that meets Standard I). Step 3: Extract the components of the non-dissolved enriched precipitate B obtained after enrichment in Step 1 to obtain the dissolved components C of the non-dissolved enriched precipitate. Conduct a component analysis on the obtained dissolved components C of the non-dissolved enriched precipitate. For the dissolved components C of the non-dissolved enriched precipitate that meets Standard I, enrich it using an ultrafiltration membrane. For the dissolved components C of the non-dissolved enriched precipitate that does not meet Standard I, conduct conditioning and component analysis until it meets Standard I, and then enrich the dissolved components C of the non-dissolved enriched precipitate that meets Standard I using an ultrafiltration membrane to obtain the second enriched liquid (i.e., the enriched dissolved components C of the non-dissolved enriched precipitate that meets Standard I). Step 4: When the transmembrane pressure difference of the ultrafiltration membrane in Step 1 is greater than 5 m or the membrane flux is less than 5 L / h·m 2 , clean the ultrafiltration membrane to obtain a cleaning solution. Concentrate and enrich the obtained cleaning solution using the ultrafiltration membrane, and then separate the liquid and solids in the enriched cleaning solution with a filter paper or microfiltration membrane to also obtain a dissolved cleaning solution D (i.e., the liquid in the enriched cleaning solution) and an undissolved cleaning precipitate E (i.e., the solids in the enriched cleaning solution); Step 5: Conduct a component analysis on the dissolved cleaning liquid D obtained in Step 4. For the dissolved cleaning liquid D that meets Standard I, concentrate and enrich it using an ultrafiltration membrane. For the dissolved cleaning liquid D that does not meet Standard I, conduct conditioning and component analysis until it meets Standard I, and then concentrate and enrich the dissolved cleaning liquid D that meets Standard I using an ultrafiltration membrane to obtain the third enriched liquid (i.e., the enriched dissolved cleaning liquid D that meets Standard I). Step 6: Extract the components of the non-dissolved cleaning precipitate E obtained in Step 4 to obtain the dissolved components F of the non-dissolved cleaning precipitate. Conduct a component analysis on the obtained dissolved components F of the non-dissolved cleaning precipitate. For the dissolved components F of the non-dissolved cleaning precipitate that meets Standard I, enrich it using an ultrafiltration membrane. For the dissolved components F of the non-dissolved cleaning precipitate that does not meet Standard I, conduct conditioning and component analysis until it meets Standard I, and then enrich the dissolved components F of the non-dissolved cleaning precipitate that meets Standard I using an ultrafiltration membrane to obtain the fourth enriched liquid (i.e., the enriched dissolved components F of the non-dissolved cleaning precipitate that meets Standard I). Step 7: Conduct a component analysis on the first enriched liquid, the second enriched liquid, the third enriched liquid, and the fourth enriched liquid. Enrich the first enriched liquid, the second enriched liquid, the third enriched liquid, or the fourth enriched liquid that does not meet Standard II until it meets Standard II. Mix the first enriched liquid, the second enriched liquid, the third enriched liquid, and the fourth enriched liquid that meet Standard II to obtain the high-molecular water supply natural biopolymer G.

2. The method according to claim 1, characterized in that, The water treatment process in Step 1 includes a conventional treatment process composed of conventional treatment units such as coagulation, sedimentation, and filtration. The relevant treatment units in the water treatment process include a pretreatment unit and a deep treatment unit, including but not limited to a coagulation-sedimentation unit, a biological treatment unit, and a membrane filtration unit. The water of each relevant treatment unit includes the sludge water discharged from the biological pretreatment unit, the sludge water discharged from the sedimentation tank and the clarifier, the backwash water of the filter, the backwash water of various packing biological filters such as activated carbon, and the concentrated water discharged from membrane filtration units such as microfiltration, ultrafiltration, and nanofiltration and / or the membrane pool water, etc., including the well water and the storage tank water of the drainage of each of the above treatment units; The collection methods in Step 1 described above include but are not limited to direct extraction, siphon extraction, collection from the enrichment liquid collection port, etc.

3. The method according to claim 1, characterized in that, The methods for component extraction in Step 3 described above include but are not limited to one or several of the following: adding water for hydraulic stirring, heating, separation (including filtration with filter paper or microfiltration membrane, centrifugation, etc.), ultrasonic treatment, acid-base extraction, etc.

4. The method according to claim 1, characterized in that, The ultrafiltration membranes in Step 1, Step 2, Step 3, Step 4, Step 5, and Step 6 are external pressure type hollow fiber ultrafiltration membranes with a pore size not greater than 0.05 μm and a membrane flux not greater than 20 L / h·m 2 .

5. The method according to claim 1, characterized in that, The standard Ⅰ in Step 1, Step 2, Step 3, Step 4, Step 5, and Step 6 is as follows: The phenol-sulfuric acid method is used to measure polysaccharides, and the Lowry method is used to measure proteins. The sum of proteins and polysaccharides, that is, the total amount of bio-polymers in the feed water, is not less than 100 mg / L, and the proportion of polysaccharides is not less than 40%.

6. The method according to claim 1, wherein The standard Ⅱ in Step 7 is as follows: The phenol-sulfuric acid method is used to measure polysaccharides, and the Lowry method is used to measure proteins. The sum of proteins and polysaccharides, that is, the total amount of bio-polymers in the feed water, is not less than 2,500 mg / L, and the proportion of polysaccharides is not less than 40%.

7. The method according to claim 1, characterized in that The specific method of enrichment by ultrafiltration membrane in Step 1, Step 2, Step 3, Step 4, Step 5, Step 6, and Step 7 is as follows: An external pressure ultrafiltration membrane is used for filtration, and the filtered water is discarded. The enrichment liquid is the concentrated water produced by the external pressure ultrafiltration membrane, that is, the water containing high concentrations of organic matter that does not pass through the ultrafiltration membrane. The specific degree of enrichment is based on whether the enrichment liquid meets Standard Ⅰ or Standard Ⅱ; The conditioning methods in Step 2, Step 3, Step 5, and Step 6 include: physical methods, chemical methods, and physical-chemical combined methods. Physical methods such as ultrasonic treatment, heating, and hydraulic stirring, chemical methods such as adding various acids, bases, inorganic salts, electrolytes, oxidants, etc., and physical-chemical combined methods such as ultrasonic treatment after acidification (such as acidification with HCl) or alkalization (such as alkalization with NaOH); The conditioning selection methods for Step 2, Step 3, Step 5, and Step 6 are as follows: For the dissolved enriched liquid A, the dissolved components C of the non-dissolved enriched precipitate, the dissolved cleaning liquid D, and the dissolved components F of the non-dissolved cleaning precipitate with a total feed water biopolymer amount higher than 100 mg / L but a polysaccharide proportion lower than 40%, physical methods are used for conditioning, such as ultrasonic waves, heating, hydraulic stirring, etc.; for the dissolved enriched liquid A, the dissolved components C of the non-dissolved enriched precipitate, the dissolved cleaning liquid D, and the dissolved components F of the non-dissolved cleaning precipitate with a total feed water biopolymer amount lower than 100 mg / L but a polysaccharide proportion higher than 40%, chemical methods for enrichment are used for conditioning, such as adding various acids and bases, inorganic salts, electrolytes, oxidants, etc.; for the dissolved enriched liquid A, the dissolved components C of the non-dissolved enriched precipitate, the dissolved cleaning liquid D, and the dissolved components F of the non-dissolved cleaning precipitate with a total feed water biopolymer amount lower than 100 mg / L and a polysaccharide proportion lower than 40%, a combined physical and chemical method for enrichment is used for conditioning, such as ultrasonic waves after acidification or alkalization.

8. The method according to claim 1, wherein The cleaning in Step 4 described above includes: (1) repeatedly cleaning with a certain amount of clear water or a gas-water mixture; (2) repeatedly cleaning by soaking with a certain amount of electrolyte solution with a concentration not higher than 0.5% in combination with a gas-water mixture; the cleaning methods include but are not limited to: (1) cross-flow cleaning on the outer side of the membrane, (2) forward and reverse flow cleaning on the inner side of the membrane, etc. The cleaning liquid collection methods include but are not limited to direct extraction, siphon extraction, and collection from the enriched liquid collection port; The separation methods in Step 1 and Step 5 described above include but are not limited to quantitative filter paper filtration and 0.45 μm microfiltration membrane suction filtration; The high-molecular-weight feed water natural biopolymer G in Step 7 is composed of one or more mixtures of the first enriched liquid, the second enriched liquid, the third enriched liquid, and the fourth enriched liquid that meet Standard II.

9. The high-molecular-weight feed water natural biopolymer prepared by the method according to any one of claims 1-8.

10. The application of the high-molecular-weight feed water natural biopolymer prepared by the method according to any one of claims 1-8, directly adding it to water as a coagulant aid to reduce the dosage of a coagulant (such as polyaluminum chloride PAC); It can be directly recycled.

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