A method for purifying water for dissolving water-soluble fertilizers or water for diluting powder fertilizers

Abstract

The application discloses a kind of water-soluble fertilizer dissolving water or powder fertilizer dilution water purification method, it is related to sewage treatment technical field, specifically including 1) equipment preset;2) sewage pretreatment;3) water purification;4) water storage;The application first prepares the corresponding modified straw for different kinds of heavy metal ions, and ensures continuous by supplementing modified straw, after 10-15d in reaction tank, after simple filtration, the purified water rich in N, P element is obtained.The application uses modified straw to adsorb heavy metal ions, also uses it as the substrate of microbial fermentation enzymolysis, increases the content of small molecule nitrogen and phosphorus in water;The application only uses a reaction tank, purifies water at low cost at the same time, reduces the use of fertilizer, is the preferred water-soluble fertilizer dissolving water or powder fertilizer dilution water purification method.

Description

TECHNICAL FIELD

[0001] The present application relates to the sewage treatment technical field, especially to a kind of water-soluble fertilizer dissolving water or powder fertilizer dilution water purification method. BACKGROUND

[0002] The sewage of each place, because of different sources, the types of pollutants contained therein, content are not all the same. In order to purify water resources more efficiently and conveniently, so that it can reach the corresponding use standard, the existing purification technology is mainly ion exchange, reverse osmosis, ultrafiltration and other means, without distinction to eliminate solid pollutants, heavy metal ions and organic matter residues in water body.

[0003] For the water used in people's daily life, this kind of processing method is undoubtedly feasible, but for the five kinds of water used in agriculture, N, P and other elements that make the water body eutrophication, are exactly the main target elements added when fertilizing crops.

[0004] Then, how to simply and efficiently remove heavy metal ions and decompose macromolecular organic matter, so that the water body is purified while being rich in plant-absorbable small molecular N, P compounds, is the research direction of the water-soluble fertilizer dissolving water or powder fertilizer dilution water purification method at present. SUMMARY

[0005] The present application aims at solving the problems existing in the prior art and provides a water-soluble fertilizer dissolving water or powder fertilizer dilution water purification method.

[0006] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0007] A water-soluble fertilizer dissolving water or powder fertilizer dilution water purification method, comprising the following steps:

[0008] S1, equipment presetting

[0009] A reaction tank and a water storage tank covered with a heat preservation film are set; the reaction tank is on the ground and is higher than the water storage tank, and the water storage tank is underground and the tank surface is flush with the ground; a water pump is connected to the left end of the reaction tank for conveying sewage; six double-layer net-like partitions are sequentially inserted into the reaction tank from the water inlet to the water outlet, each partition is 1m apart, and a 10cm wide space is left in each partition; and the right end of the reaction tank is connected to the water storage tank.

[0010] The reaction tank partitions are filled with straw, and the straw is esterified modified straw, etherified modified straw, alkali modified straw, magnetic modified straw, combined modified straw and compound microbial agent straw in sequence.

[0011] The area between the water outlet end of the reaction tank and the sixth layer of net-like partitions is a fermentation and enzymatic hydrolysis zone, and the distance is 5-10m.

[0012] The fermentation enzyme hydrolysis zone is provided with an air blower with an outlet pressure of 0.015-0.2 MPa for aeration, a heavy metal detector, a total phosphorus and total nitrogen analyzer and other detection equipment for detecting pollutants in the water quality, and a valve-equipped pipeline is connected to the water storage tank, and a layer of ceramic ultrafiltration membrane is arranged between the reaction tank and the water storage tank;

[0013] S2, pretreatment

[0014] In the interlayer gap, 10 kg of esterification modified straw, etherification modified straw, alkali modified straw, magnetic modified straw, combined modified straw and compound microbial agent straw are respectively filled; after the sewage is blocked by the screen to block solid waste, the sewage is pumped into the reaction tank by the water pump, and the pretreated sewage is obtained after the preliminary purification of the sewage;

[0015] S3, water purification

[0016] The valve between the closed reaction tank and the water storage tank is closed, and the pretreated sewage is introduced into the reaction tank;

[0017] The heavy metal detector, the total phosphorus and total nitrogen analyzer and other detection equipment are used to detect the pollutants in the water quality, and when the content of heavy metals exceeds the standard, the sewage is stopped and the corresponding straw is replaced;

[0018] The pretreated sewage is aerated by the air blower for 30 minutes every day to precipitate calcium and magnesium ions, reduce the hardness of the water, achieve softening of hard water and increase the dissolved oxygen content of the water body; the reaction temperature is controlled at 25-35℃, and after the pretreated sewage is treated in the reaction tank for 10-15 days, the eutrophication impurity water is obtained;

[0019] The air blower aeration makes CO2 in the water escape, the pH is improved to promote Ca 2+ / Mg 2+ Form CaCO3 / Mg(OH)2 precipitation. At the same time, air is blown into the water to increase the content of dissolved oxygen in the water, and the dissolved oxygen must be maintained at ≥4 mg / L by aeration or other methods, otherwise the activity of the microbial agent will decrease.

[0020] S4, water storage

[0021] The valve between the reaction tank and the water storage tank is opened, and the water pump is used to extract the eutrophication impurity water through the ceramic ultrafiltration membrane and flow into the water storage tank to obtain the purified water which can be applied to the dissolution of water-soluble fertilizer or the dilution of powder fertilizer.

[0022] Preferably, the modified straw in S1 and the preparation method thereof specifically comprise:

[0023] ① Esterification modified straw:

[0024] The wheat raw straw is mixed with 0.6 mol / L citric acid aqueous solution at a mass ratio of 1:12, stirred at 20°C for 0.5 h to obtain citric acid wheat straw; the citric acid wheat straw is placed on a tray and dehydrated in an oven at 50°C for 24 h, and then esterification is carried out at 120°C for 1.5 h; after cooling, the excess acid is removed by washing twice with distilled water and filtering to obtain esterified straw; the esterified straw is added into 0.1 mol / L NaOH aqueous solution with the same mass as the citric acid aqueous solution, stirred for 1 h, washed twice with distilled water to remove excess base, and filtered to obtain esterified modified straw;

[0025] The esterified modified straw can efficiently adsorb Cu 2+ , and a certain amount of methylene blue, and the adsorption amount of methylene blue is above 360 mg / g; 2+ , and a certain amount of methylene blue, and the adsorption amount of methylene blue is above 360 mg / g;

[0026] 2) Etherified modified straw:

[0027] The wheat raw straw is mixed with epichlorohydrin and N,N-dimethylformamide DMF, heated to 85°C, and kept for 1 h; ethylenediamine is added, stirred at 85°C and 180 rpm for 45 min; triethylamine is added, stirred at 85°C and 180 rpm for 2 h; after washing twice with distilled water, the etherified modified straw is obtained by filtering;

[0028] The mass ratio of the wheat raw straw, epichlorohydrin, N,N-dimethylformamide, ethylenediamine and triethylamine is 5:6:4:3:3;

[0029] The etherified modified straw can efficiently adsorb Cr 6+ , and a certain amount of methylene blue, and the adsorption amount of methylene blue is above 360 mg / g; 6+ , and a certain amount of Ni 2+ , and methyl orange, and the adsorption amount of Ni 2+ is above 5 mg / g, and the adsorption amount of methyl orange is above 300 mg / g;

[0030] 3) Alkali modified straw:

[0031] The wheat raw straw is mixed with 4 mol / L KOH aqueous solution at a mass ratio of 1:1 at 100°C for 2 h, then cooled to room temperature, filtered, washed twice with distilled water, and filtered to obtain the alkali modified straw;

[0032] The alkali modified straw can efficiently adsorb chlorosulfuron herbicide and Cd 2+ , and a certain amount of methylene blue, and the adsorption amount of methylene blue is above 360 mg / g; 2+ The adsorption amount is above 15 mg / g;

[0033] 4) Magnetic modified straw:

[0034] Raw wheat straw was added to a solution of FeCl3 and FeSO4 iron ions under a nitrogen atmosphere, where Fe... 3+ with Fe 2 + A ferric ion straw mixture was obtained with a molar ratio of 2:1. The ferric ion straw mixture was then mixed with a 25% NH3·H2O aqueous solution, heated to 70℃, and kept warm for 4 hours to obtain magnetic straw. The magnetic straw was washed twice with distilled water, filtered, and the magnetic modified straw was obtained. The magnet was recovered.

[0035] The mass ratio of raw wheat straw, iron ion solution, and NH3·H2O aqueous solution is 1:100:4;

[0036] Magnetic modified straw can efficiently adsorb Pb 2+ With As 5+ For Pb 2+ The adsorption capacity is above 40 mg / g, for As 5+ The adsorption capacity is above 5 mg / g;

[0037] ⑤ Modified straw in combination:

[0038] Rice straw was dispersed in a 1 mol / L HNO3 aqueous solution, stirred at 180 rpm for 1 h, filtered, and washed twice with distilled water to obtain acidified rice straw. The acidified rice straw was then dispersed in a 0.75 mol / L NaOH aqueous solution, stirred at 180 rpm for 1 h, washed twice with distilled water, and filtered to obtain combined modified straw.

[0039] The mass ratio of rice straw, 1 mol / L HNO3 aqueous solution, and 0.75 mol / L NaOH aqueous solution is 1:5:10.

[0040] Combined modified straw can efficiently adsorb Zn 2+ Hg 2+ For Zn 2+ The adsorption capacity is above 40 mg / g, for Hg 2+ The adsorption capacity is above 300 mg / g;

[0041] ⑥ Compound microbial agent straw:

[0042] Mix 1 kg of compound microbial agent with warm water (35℃-38℃) and nutrient solution (such as molasses), stir for 24 hours to activate the microbial community, immerse raw wheat straw in the nutrient solution and keep warm for 4 hours to obtain compound microbial agent straw.

[0043] Preferably, the bacterial species in the compound microbial agent in S1 specifically include: Pseudomonas, Bacillus, Trichoderma, Proteus, Acinetobacter, Nitrosinophils, and Nitrosinophils, and the bacterial content is the standard compound microbial agent content, that is, the effective viable count is ≥200 million / g.

[0044] The microbial agent ferments and enzymatically hydrolyzes the organic macromolecules adsorbed on the surface of straw, continuously releasing small molecule sugars, which in turn promotes the proliferation of the microbial community;

[0045] Preferably, the positions of esterified modified straw, etherified modified straw, alkali modified straw, magnetic modified straw, and combined modified straw can be changed at will.

[0046] Preferably, the ceramic ultrafiltration membrane in S1 has a pore size of 0.02 μm.

[0047] Ceramic ultrafiltration membranes with a pore size of 0.02 μm can filter macromolecules with a molecular weight of 10,000 Da and solid particles with a particle size of 0.02 μm or larger. For pollutants in the reaction tank, their molecular weight is much greater than 10,000 Da before they are degraded.

[0048] Preferably, the purified water obtained by the present invention meets the Class V water standard for heavy metal ion content, but the N and P elements are too high, so it can only be used for agricultural fertilization and cannot be used as domestic water.

[0049] For general agricultural water use, i.e., Class V water, the standards for various pollutants are: total nitrogen ≤ 2.0 mg / L, total phosphorus ≤ 0.4 mg / L, and Cu ≤ 0.5 mg / L. 2+ Content ≤1.0mg / L, Zn 2+ Content ≤2.0mg / L, As 5+ Content ≤0.1mg / L, Hg 2+ Content ≤0.001mg / L, Cd 2+ Content ≤0.01mg / L, Cr 6+ Content ≤0.1mg / L, Pb 2+ Content ≤0.1mg / L;

[0050] To address these major pollutants, this invention uses a reaction tank to treat most of the pollutants in one go through both physical and biological methods. That is, while adsorbing and precipitating heavy metal ions and various dyes, microorganisms decompose organic macromolecules. At this time, N and P nutrients are converted into nitrate nitrogen and dissolved phosphorus by the ammonification and nitrification of compound bacterial agents (nitrite bacteria and nitrate bacteria), which can be directly utilized by water-soluble fertilizers.

[0051] The presence of heavy metals inhibits the activity of the bacterial population, but the rate of the physical adsorption process is much higher than that of the biological fermentation enzymatic process, and the adsorption kinetics shows that most heavy metal ions reach adsorption equilibrium within 60-120 min; when a specific heavy metal is present in large quantities, the corresponding modified straw performs a targeted adsorption function; after the wastewater passes through the modified straw, the content of heavy metal ions in the wastewater decreases to within the limited standard of Class V water, and at the same time, the bacterial population starts the fermentation enzymatic process, and the pseudomonas and bacillus decompose organic macromolecules, and the trichoderma degrades the straw to release nutrients required by the bacterial population, but this biological degradation process takes much longer, for example, the nitrification and denitrification processes may take 6-24 hours. Therefore, the total treatment time is determined by the biological treatment stage.

[0052] Calcium and magnesium ions are not pollutants, but their excessive content is the main factor causing water hardness, so after the pollutant treatment is completed, an additional water softening process is required.

[0053] It is not desirable to completely precipitate calcium and magnesium ions, because calcium is an important component of plant cell walls, and magnesium is a component of chlorophyll, both of which play an important role in the growth and development of plants.

[0054] The air blowing aeration not only can soften the hard water without using other chemical agents, but also can supplement the dissolved oxygen consumed by the aerobic bacteria in the reaction tank, thereby ensuring the activity of the microorganisms.

[0055] Compared with the prior art, the present application has the following beneficial effects:

[0056] The present application activates the specific adsorption sites of the straw by chemical modification for different pollutants (heavy metals / dyes), and obtains five types of modified straws;

[0057] The esterified straw citric acid group chelates Cu 2+ ; the etherified straw amine group captures Cr 4+ / Ni 2+ ; the alkali modified straw enhances the chelation of Cd 2+ ; the magnetic straw adsorbs Pb 2+ / As 2+ ; the combined modified rice straw adsorbs Zn 2+ / Hg 2+ The adsorption covers the main pollution elements of the existing water body in addition to biological macromolecules.

[0058] The raw materials used in the five types of modified straws are low in price, easy to obtain, and the production conditions are not harsh; the straw is not only a carrier of adsorption groups, but also a fermentation substrate of microorganisms, which ensures the survival of the bacterial population and also provides additional nutrients for the cultivation of crops, reducing the use of fertilizers.

[0059] Generally, inoculation uses composite microbial inoculants, which need to be subjected to solid-state fermentation or liquid fermentation before being put into use; but the total nitrogen and total phosphorus content of the sewage exceeding the limited standard of class V water, after pretreatment and straw adsorption of heavy metal ions, only needs to provide suitable temperature and oxygen, and the composite microbial flora can grow vigorously, decompose organic pollutants, and produce small molecules (≤500 Da) that can be directly absorbed and utilized by crops.

[0060] The air blower blows air to supplement the dissolved oxygen consumed by the aerobic bacteria in the reaction tank, shakes the water body to make CO2 escape, and precipitates part of the calcium and magnesium ions to achieve the effect of hard water softening.

[0061] In summary, the linkage effect of modified straw and microbial inoculants is used to simultaneously achieve the purposes of removing heavy metal ions, decomposing organic pollutants, and hard water softening in one reaction tank, and the water purification method for dissolving water-soluble fertilizer or diluting powder fertilizer is energy-saving, simple, and has additional value. BRIEF DESCRIPTION OF DRAWINGS

[0062] Figure 1 The process flow diagram of the water purification method for dissolving water-soluble fertilizer or diluting powder fertilizer is shown in the figure. DETAILED DESCRIPTION

[0063] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments.

[0064] The specifications and manufacturers of the various drugs used in the experiment are shown in Table 1:

[0065] Table 1. Raw drug information

[0066]

[0067] Example 1:

[0068] A water purification method for dissolving water-soluble fertilizer or diluting powder fertilizer, comprising the following steps:

[0069] S1, device presetting

[0070] A reaction tank and a water storage tank covered with a heat preservation film are set; the reaction tank is 11 m long and 2 m wide, is located on the ground, is higher than the water storage tank, and has a capacity of 100 m 3 The pool surface is flush with the ground; a water pump is connected to the left end of the reaction tank for conveying

[0071] Sewage, the reaction tank from the water inlet to the water outlet, in turn, inserted 6 double-layer mesh partition, each layer partition 1 m apart, layer left 10 cm wide space, the right end of the reaction tank connected with the reservoir;

[0072] The reaction tank is filled with straw, which is esterification modified straw, etherification modified straw, alkali modified straw, magnetic modified straw, combined modified straw and composite microbial agent straw.

[0073] The area between the water outlet end of the reaction tank and the sixth layer of mesh partition is the fermentation and enzymatic hydrolysis zone, with a distance of 5 m.

[0074] The fermentation and enzymatic hydrolysis zone is provided with a blower with an outlet pressure of 0.015 MPa for aeration, a heavy metal detector, a total phosphorus and total nitrogen analyzer, and other detection equipment for detecting pollutants in water quality, and a valve-equipped pipeline connecting the reservoir. A layer of ceramic ultrafiltration membrane with a pore size of 0.02 μm is arranged between the reaction tank and the reservoir.

[0075] The HM-5000P type (multi-functional) portable water quality heavy metal detector and the Hash NPW-160H total phosphorus and total nitrogen analyzer are used to detect the water quality. According to the pollution detection report, the total nitrogen content of the sewage treated this time is 4.36 mg / L, the total phosphorus content is 1.07 mg / L, the Cu content is 2.48 mg / L, the Zn content is 1.91 mg / L, the As content is 0.12 mg / L, the Hg content is 0.002 mg / L, the Cd content is 0.21 mg / L, the Cr content is 0.15 mg / L, the Pb content is 0.23 mg / L. 2+ 2+ 5+ 2+ 2+ 6+ 2+

[0076] S2, sewage pretreatment

[0077] Esterification modified straw, etherification modified straw, alkali modified straw, magnetic modified straw, combined modified straw and composite microbial agent straw are respectively filled in the gap between the partitions, each 10 kg.

[0078] After the sewage is blocked by the screen to block solid waste, it is pumped into the reaction tank. After the preliminary purification of the sewage, pretreated sewage is obtained.

[0079] S3, water purification

[0080] Close the valve between the reaction tank and the reservoir, and pour the pretreated sewage into the reaction tank.

[0081] ​​​​​​​The wastewater of the fermentation enzymolysis zone is detected by using a heavy metal detector, a total phosphorus and total nitrogen analyzer and other detection equipment. When the content of heavy metal exceeds the standard, the wastewater is stopped and the corresponding straw is replaced.

[0082] The pretreated wastewater is aerated by the air blower for 30 minutes every day to precipitate calcium and magnesium ions, reduce the hardness of the water, achieve the softening of hard water and increase the dissolved oxygen content of the water body.

[0083] The reaction temperature is controlled at 25-35°C. After the pretreated wastewater is treated in the reaction tank for 10 days, the eutrophication impurity water is obtained.

[0084] S4, water storage

[0085] The valve between the reaction tank and the water storage tank is opened, the eutrophication impurity water is extracted by the water pump, passes through the ceramic ultrafiltration membrane, flows into the water storage tank, and the purified water which can be applied to the dissolution of water-soluble fertilizer or the dilution of powder fertilizer is obtained.

[0086] Example 2:

[0087] S1, equipment preset

[0088] The reaction tank and the water storage tank which can be covered with a heat preservation film are set. The reaction tank is 13.5m long and 2m wide, is on the ground, is higher than the water storage tank, the water storage tank is underground, and has a capacity of 100m 3 The pool surface is flush with the ground. One water pump is connected to the left end of the reaction tank for transporting wastewater. Six double-layer net-like partitions are sequentially inserted into the reaction tank from the water inlet to the water outlet. Each partition is 1m apart, and a space of 10cm wide is left in each partition. The right end of the reaction tank is connected to the water storage tank.

[0089] The partitions in the reaction tank are filled with straws, which are esterification modified straws, etherification modified straws, alkali modified straws, magnetic modified straws, combined modified straws and composite bacterial agent straws in sequence.

[0090] The area between the water outlet end of the reaction tank and the sixth layer of net-like partitions is the fermentation enzymolysis zone, and the distance is 7.5m.

[0091] The fermentation enzymolysis zone is provided with an air blower with an outlet pressure of 0.015MPa for aeration. A heavy metal detector, a total phosphorus and total nitrogen analyzer and other detection equipment are used to detect the pollutants in the water quality. A ceramic ultrafiltration membrane with a pore size of 0.02μm is arranged between the reaction tank and the water storage tank.

[0092] The water quality is detected by using a HM-5000P type (multifunctional) portable water quality heavy metal detector and a Hash NPW-160H total phosphorus and total nitrogen analyzer. According to the pollution detection report, the total nitrogen content of various pollutants in the treated wastewater is 3.42mg / L, the total phosphorus content is 2.61mg / L, Cu2+ Content = 16.74 mg / L, Zn 2+ Content = 3.49 mg / L, As 5+ Content = 0.18 mg / L, Hg 2+ Content = 0.021 mg / L, Cd 2+ Content = 0.13 mg / L, Cr 6+ Content = 0.22 mg / L, Pb 2+ Content = 0.29 mg / L;

[0093] S2, sewage pretreatment

[0094] Fill the esterification modified straw, etherification modified straw, alkali modified straw, magnetic modified straw, combined modified straw, and compound microbial agent straw in the interlayer gap, respectively, with 10 kg each;

[0095] After the sewage is blocked by the solid waste, the sewage is pumped into the reaction tank, and the pretreated sewage is obtained after the preliminary purification of the sewage;

[0096] S3, water purification

[0097] Close the valve between the reaction tank and the water storage tank, and pour the pretreated sewage into the reaction tank;

[0098] The water quality is detected by using a heavy metal detector, a total phosphorus and nitrogen analyzer, and other detection equipment for the sewage in the fermentation and enzymatic hydrolysis zone. When the content of heavy metals exceeds the standard, stop feeding the sewage and replace the corresponding straw;

[0099] The pretreated sewage is aerated for 30 minutes every day by the air blower to precipitate calcium and magnesium ions, reduce the hardness of the water, achieve softening of hard water, and increase the dissolved oxygen content of the water body;

[0100] The reaction temperature is controlled at 25-35℃, and the pretreated sewage is treated in the reaction tank for 12.5 days to obtain eutrophication impurity water;

[0101] S4, water storage

[0102] Open the valve between the reaction tank and the water storage tank, and use the water pump to extract the eutrophication impurity water through the ceramic ultrafiltration membrane and flow into the water storage tank to obtain purified water that can be applied to the dissolution of water-soluble fertilizer or the dilution of powder fertilizer.

[0103] Example 3:

[0104] S1, equipment preset

[0105] Set the reaction tank and the water storage tank that can cover the heat preservation film; the reaction tank is 16 m long and 2 m wide, located on the ground and higher than the water storage tank, and the water storage tank is underground with a capacity of 100 m 3, the pool surface is flush with the ground; a water pump is connected to the left end of the reaction pool for conveying sewage, and the reaction pool is sequentially inserted with six double-layer net-like partitions from the water inlet to the water outlet, each partition is 1 m apart, and a space of 10 cm wide is left in each partition, and the right end of the reaction pool is connected to the water storage pool;

[0106] The reaction pool partitions are filled with straw, which is esterification modified straw, etherification modified straw, alkali modified straw, magnetic modified straw, combined modified straw, and composite microbial agent straw in sequence;

[0107] The area between the reaction pool water outlet end and the sixth layer of net-like partitions is a fermentation and enzymatic hydrolysis zone, with a distance of 10 m;

[0108] A blower with an outlet pressure of 0.015 MPa is provided in the fermentation and enzymatic hydrolysis zone for aeration, a heavy metal detector, a total phosphorus and total nitrogen analyzer, and other detection equipment are provided for water quality pollution detection, and a valve-equipped pipeline is connected to the water storage pool, a layer of ceramic ultrafiltration membrane with a pore size of 0.02 μm is provided between the reaction pool and the water storage pool;

[0109] The HM-5000P type (multifunctional) portable water quality heavy metal detector and the Hash NPW-160H total phosphorus and total nitrogen analyzer are used for water quality detection, according to the pollution detection report, the total nitrogen content of the treated sewage is 4.03 mg / L, the total phosphorus content is 0.85 mg / L, the Cu 2+ content is 3.80 mg / L, the Zn 2+ content is 4.61 mg / L, the As 5+ content is 0.48 mg / L, the Hg 2+ content is 0.001 mg / L, the Cd 2+ content is 0.07 mg / L, the Cr 6+ content is 0.44 mg / L, and the Pb 2+ content is 0.34 mg / L;

[0110] S2, sewage pretreatment

[0111] Esterification modified straw, etherification modified straw, alkali modified straw, magnetic modified straw, combined modified straw, and composite microbial agent straw are respectively filled in the gap between the partitions, each 10 kg;

[0112] After the sewage is blocked by the screen to block solid waste, it is pumped into the reaction pool by the water pump, and after the sewage is preliminarily purified, pretreated sewage is obtained;

[0113] S3, water purification

[0114] Close the valve between the reaction pool and the water storage pool, and pour the pretreated sewage into the reaction pool;

[0115] The wastewater of the fermentation enzymolysis zone is detected by using a heavy metal detector, a total phosphorus and total nitrogen analyzer and other detection equipment to detect the pollutant content of the water quality. When the content of heavy metal exceeds the standard, stop feeding the wastewater and replace the corresponding straw;

[0116] The pretreated wastewater is aerated by the air blower for 30 minutes every day to precipitate calcium and magnesium ions, reduce the hardness of the water and realize the softening of hard water and the increase of the dissolved oxygen content of the water body;

[0117] The reaction temperature is controlled at 25-35℃. After the pretreated wastewater is treated in the reaction tank for 15 days, the eutrophication impurity water is obtained.

[0118] S4, water storage

[0119] The valve between the reaction tank and the water storage tank is opened, the eutrophication impurity water is extracted by the water pump, passes through the ceramic ultrafiltration membrane and flows into the water storage tank to obtain the purified water which can be applied to the dissolution of water-soluble fertilizer or the dilution of powder fertilizer.

[0120] Comparative Example 1: The wastewater treated in Example 2 is the same, the added modified straw and the complex microbial agent are also the same, but no esterified modified straw is added;

[0121] Comparative Example 2: The wastewater treated in Example 2 is the same, the added modified straw and the complex microbial agent are also the same, but no etherified modified straw is added;

[0122] Comparative Example 3: The wastewater treated in Example 2 is the same, the added modified straw and the complex microbial agent are also the same, but no alkali modified straw is added;

[0123] Comparative Example 4: The wastewater treated in Example 2 is the same, the added modified straw and the complex microbial agent are also the same, but no magnetic modified straw is added;

[0124] Comparative Example 5: The wastewater treated in Example 2 is the same, the added modified straw and the complex microbial agent are also the same, but no combined modified straw is added;

[0125] Comparative Example 6: The wastewater treated in Example 2 is the same, the added modified straw and the complex microbial agent are also the same, but no complex microbial agent is added;

[0126] Comparative Example 7: The wastewater treated in Example 2 is the same, the added modified straw and the complex microbial agent are also the same, but the treatment time is 5 days;

[0127] Comparative Example 8: The wastewater treated in Example 2 is the same, the added modified straw and the complex microbial agent are also the same, but the treatment time is 7.5 days;

[0128] Comparative Example 9: The wastewater treated in Example 2 is the same, the added modified straw and the complex microbial agent are also the same, but the treatment time is 10 days;

[0129] Comparative Example 11: The same sewage as treated in Example 2, the same modified straw and complex microbial agent added, but the treatment time was 17.5 days;

[0130] Comparative Example 11: The same sewage as treated in Example 2, the same modified straw and complex microbial agent added, but the treatment time was 17.5 days;

[0131] Comparative Example 12: The same sewage as treated in Example 2, the same modified straw and complex microbial agent added, but the treatment time was 20 days;

[0132] Comparative Example 13: The same sewage as treated in Example 2, the same modified straw and complex microbial agent added, but the length of the reaction tank was 8 meters;

[0133] Comparative Example 14: The same sewage as treated in Example 2, the same modified straw and complex microbial agent added, but the length of the reaction tank was 20 meters;

[0134] That is, as shown in Table 2:

[0135] Table 2. Different groups of modified straw and complex microbial agent addition amount and process statement table

[0136]

[0137] By detecting the small molecule nitrogen and phosphorus, Cu 2+ , Zn 2+ , As 5+ , Hg 2+ , Cd 2+ , Cr 6+ , Pb 2+ and other heavy metal ions, and Ca 2+ , Mg 2+ content of Comparative Examples 1-16 and Examples 1-3, the detection results are shown in Table 3:

[0138] Table 3. Purified water quality detection table

[0139]

[0140] Data analysis:

[0141] By comparing Example 1, Example 2, Example 3, and Comparative Example 1, as a modified straw that specializes in adsorbing Cu 2+ , for Cu 2+ content exceeding the sewage, esterification modified straw is indispensable in the composition, but excessive addition cannot completely remove Cu 2+ in the water body, when the Cu 2+ in the water body is too small, part of the adsorbed will be released in the process of blowing air by the air blower.

[0142] Similarly, by comparing Example 1, Example 2, Example 3, and Comparative Example 2; by comparing Example 1, Example 2, Example 3, and Comparative Example 3; by comparing Example 1, Example 2, Example 3, and Comparative Example 4; by comparing Example 1, Example 2, Example 3, and Comparative Example 5, it can be known that the etherification modified straw, the alkali modified straw, the magnetic modified straw, and the combined modified straw have a significant effect on the heavy metal ions that can be adsorbed, and can also adsorb part of other heavy metal elements, but the adsorption effect is limited, such as in Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, and Comparative Example 5, although one kind of modified straw is added to each group, the content of the corresponding heavy metal ions is still reduced by a small amount.

[0143] By comparing Example 1, Example 2, Example 3, and Comparative Example 6, it can be known that the complex microbial agent selected by the present application can effectively decompose various organic pollutants in wastewater and generate small-molecule organic matter, and at the same time, the number of microorganisms that can be supported by one round of wastewater is limited, and appropriate addition according to the amount and pollutant concentration of the treated wastewater is sufficient, without the need for excessive addition.

[0144] By comparing Example 1, Example 2, Example 3, and Comparative Example 7, Comparative Example 8, Comparative Example 9, Comparative Example 10, Comparative Example 11, and Comparative Example 12, it can be known that the treatment time of heavy metal ions in wastewater is much shorter than the treatment time of organic matter, and when the treatment days are less than the preferred range, the content of heavy metal ions will also decrease to within the standard under the premise of appropriate modified straw, and the process of blowing air into the water is a process of supplementing the dissolved oxygen in the water and a process of softening hard water, and in 10-15d, the microbial population proliferates, and most of the organic pollutants are degraded into small molecules, and after filtration by the ceramic ultrafiltration membrane, the water can be put into use.

[0145] By comparing Example 1, Example 2, Example 3, and Comparative Example 13, Comparative Example 14, it can be known that when the area of the enzymatic fermentation zone is too large, the time of wastewater flowing through the modified straw will also be reduced, the heavy metal adsorption will not be timely, part of the microorganisms will be inactivated, and the water purification effect will be poor, but when the area is too small, the quality of the water purified at one time is too small, which does not meet the demand of agricultural water.

[0146] In summary, the present application realizes the purposes of removing heavy metal ions, decomposing organic pollutants, and softening hard water in one reaction tank through the linkage effect of modified straw and microbial strains, but the modified straw, the complex microbial agent, and the treatment time should not be excessive, and thus, in an energy-saving and simple way, water for dissolving water-soluble fertilizer or water for diluting powder fertilizer that is less polluted and rich in N and P elements is obtained.

[0147] The above merely describes preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art, according to the technical solution and inventive concept of the present application, makes equivalent replacement or change within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for purifying water for dissolving water-soluble fertilizers or water for diluting powder fertilizers, characterized by, The method comprises the following steps: S1, device presetting A reaction tank and a water storage tank capable of covering the heat preservation film are arranged; the reaction tank is arranged on the ground and is higher than the water storage tank; the water storage tank is arranged underground and the pool surface is flush with the ground; a water pump is connected to the left end of the reaction tank for conveying sewage; the reaction tank is connected to the water storage tank at the right end; six double-layer net-like partitions are sequentially inserted into the reaction tank from the water inlet to the water outlet; each partition is spaced apart by 1 m; a space with a width of 10 cm is reserved in each partition; the water storage tank is connected to the right end of the reaction tank; Straw is filled in the partitions of the reaction tank; the straws are sequentially citric acid esterification modified straw, amine grafting etherification modified straw, potassium hydroxide alkali modified straw, ferroferric oxide magnetic modified straw, acidification-alkalization two-step modified straw and composite inoculum inoculated straw; The area between the water outlet end of the reaction tank and the sixth net-like partition is a fermentation and enzymatic hydrolysis zone, and the distance is 5-10 m; An air blower with an outlet pressure of 0.015-0.2 MPa is arranged in the fermentation and enzymatic hydrolysis zone for aeration; a heavy metal detector, a total phosphorus and total nitrogen analyzer and other detection equipment are arranged for detecting the water quality; a pipe with a valve is connected to the water storage tank; a layer of ceramic ultrafiltration membrane is arranged between the reaction tank and the water storage tank; S2, pretreatment 10 kg of citric acid esterification modified straw, amine grafting etherification modified straw, potassium hydroxide alkali modified straw, ferroferric oxide magnetic modified straw, acidification-alkalization two-step modified straw and composite inoculum inoculated straw are respectively filled in the gaps between the partitions; after the sewage is blocked by the net, the sewage is pumped into the reaction tank by the water pump; after the preliminary purification of the sewage, pretreated sewage is obtained; S3, water purification The valves of the reaction tank and the water storage tank are closed; the pretreated sewage is poured into the reaction tank; The water quality of the sewage in the fermentation and enzymatic hydrolysis zone is detected by using the heavy metal detector, the total phosphorus and total nitrogen analyzer and other detection equipment; when the heavy metal content exceeds the standard, the sewage is stopped and the corresponding straw is replaced; The pretreated sewage is aerated by the air blower for 30 min every day to precipitate calcium and magnesium ions, reduce the hardness of the water and realize hard water softening and improve the dissolved oxygen content of the water body; The reaction temperature is controlled at 25-35℃; after the pretreated sewage is treated in the reaction tank for 10-15 days, eutrophication impurity water is obtained; S4, water storage The valves of the reaction tank and the water storage tank are opened; the eutrophication impurity water is pumped into the water storage tank through the ceramic ultrafiltration membrane by using the water pump; purified water which can be applied to the dissolution of water-soluble fertilizer or the dilution of powder fertilizer is obtained.

2. The purification method of water for dissolving a water-soluble fertilizer or water for diluting a powder fertilizer according to claim 1, characterized by, The modified straw in S1 and the preparation method thereof specifically comprise: ① Citric acid esterification modified straw: Wheat straw is stirred with 0.6 mol / L citric acid aqueous solution at a mass ratio of 1:12 at 20℃ for 0.5 h to obtain citric acid wheat straw; the citric acid wheat straw is dehydrated in a tray in an oven at 50℃ for 24 h, and then subjected to esterification reaction at 120℃ for 1.5 h; after cooling, the excess acid is removed by washing twice with distilled water and filtering to obtain esterified straw; the esterified straw is added into 0.1 mol / L NaOH aqueous solution with the same mass as the citric acid aqueous solution, stirred for 1 h, washed twice with distilled water to remove excess alkali, and filtered to obtain citric acid esterification modified straw; Citrate-modified straw can efficiently adsorb Cu 2+ , Cu 2+ The adsorption capacity is above 35 mg / g, and a certain amount of methylene blue is adsorbed, and the adsorption capacity of methylene blue is above 360 mg / g; ② Amine grafting etherification modified straw: The wheat raw straw is mixed with epichlorohydrin and N, N-dimethylformamide, heated to 85 DEG C, and kept for 1h; ethylenediamine is added, stirred at 85 DEG C and 180 rpm for 45 min, triethylamine is added, stirred at 85 DEG C and 180 rpm for 2h; after rinsing twice with distilled water, the amine group grafted etherification modified straw is obtained by filtration; The mass ratio of the wheat raw straw, epichlorohydrin, N, N-dimethylformamide, ethylenediamine and triethylamine is 5:6:4:3:3; The potassium hydroxide alkali modified straw is obtained by mixing the wheat raw straw with 4 mol / L KOH aqueous solution at a mass ratio of 1:1 at 100 DEG C for 2h, then cooling to room temperature, filtering and rinsing twice with distilled water; The ferroferric oxide magnetic modified straw is obtained by mixing the wheat raw straw with 4 mol / L KOH aqueous solution at a mass ratio of 1:1 at 100 DEG C for 2h, then cooling to room temperature, filtering and rinsing twice with distilled water; The acidification-alkalization two-step modified straw is obtained by dispersing the rice raw straw in 1 mol / L HNO3 aqueous solution, stirring at 180 rpm for 1h, filtering and rinsing twice with distilled water, dispersing the acidified rice raw straw in 0.75 mol / L NaOH aqueous solution, stirring at 180 rpm for 1h, rinsing twice with distilled water and filtering; The wheat raw straw is added into the iron ion solution of FeCl3 and FeSO4 under nitrogen atmosphere, wherein the molar ratio of FeCl3 to FeSO4 is 2:1, to obtain an iron ion straw mixture; the iron ion straw mixture is mixed with the 25% NH3·H2O aqueous solution, heated to 70°C, and kept for 4h to obtain the magnetic straw, which is washed twice with distilled water, filtered to obtain the Fe3O4 magnetic modified straw, and the magnet is recycled. 3+ The molar ratio of FeCl3 to FeSO4 is 2:

1. 2+ The molar ratio of FeCl3 to FeSO4 is 2:

1. The iron ion straw mixture is mixed with the 25% NH3·H2O aqueous solution, heated to 70°C, and kept for 4h to obtain the magnetic straw, which is washed twice with distilled water, filtered to obtain the Fe3O4 magnetic modified straw, and the magnet is recycled. The mass ratio of the rice raw straw, 1 mol / L HNO3 aqueous solution and 0.75 mol / L NaOH aqueous solution is 1:5:10; The composite inoculum inoculated straw is obtained by mixing 1 kg of the composite inoculum with warm water at 35 DEG C-38 DEG C, nutrient solution, stirring for 24h to activate the bacterial population, and immersing the wheat raw straw in the nutrient solution for 4h. The bacterial species of the composite inoculum in S1 specifically include Pseudomonas, Bacillus, Trichoderma, Proteus, Acinetobacter, Nitrite bacteria and Nitrate bacteria, and the bacterial content is the standard composite inoculum content, i.e. the effective viable bacterial count is ≥2.0 billion / g. The positions of the citric acid esterification modified straw, the amine group grafted etherification modified straw, the potassium hydroxide alkali modified straw, the ferroferric oxide magnetic modified straw and the acidification-alkalization two-step modified straw in S1 can be randomly changed. The pore size of the ceramic ultrafiltration membrane in S1 is 0.02 μm. The purified water has a heavy metal ion content meeting the V-class water standard, and can only be used for agricultural fertilization, and cannot be used as domestic water.

3. The method of purifying water for dissolving a water-soluble fertilizer or water for diluting a powder fertilizer according to claim 1, characterized by, ​ 4. The method for purifying water for dissolving a water-soluble fertilizer or water for diluting a powder fertilizer according to claim 1, characterized by, ​ 5. The method of purifying water for dissolving a water-soluble fertilizer or water for diluting a powder fertilizer according to claim 1, characterized by, ​ 6. The method for purifying water for dissolving a water-soluble fertilizer or water for diluting a powder fertilizer according to claim 1, characterized by, ​

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