Aquatic plant planting matrix filler for sewage treatment and preparation method thereof

Abstract

The invention relates to the technical field of water treatment, and particularly discloses an aquatic plant planting matrix filler for sewage treatment and a preparation method of the aquatic plant planting matrix filler. The aquatic plant planting matrix filler for sewage treatment is prepared from the following raw materials in parts by weight: 20-45 parts of ferric oxide; 15 to 25 parts of aluminum oxide; 2-10 parts of calcium oxide; 5 to 15 parts of silicon dioxide; 1-10 parts of tourmaline powder; 15 to 50 parts of carbon material powder; 15 to 20 parts of Ca / Mg-biochar; 0.5 to 2 parts of a binder; 10 to 50 parts of water; 0.1 to 1 part of titanium dioxide; the preparation method comprises the following steps: mixing the raw materials, grinding, rolling into a planting green body, distributing holes, firing, and naturally cooling to obtain the aquatic plant planting matrix filler. The composition can be used for being matched with a sewage treatment A / O process, has an efficient comprehensive sewage purification effect, and can achieve the chemical oxygen demand removal efficiency of 90% or above.

Description

Technical Field

[0001] This application relates to the technical field of water treatment, and particularly to an aquatic plant planting matrix filler for sewage treatment and its preparation method. Background Art

[0002] The anaerobic / aerobic process (A / O process) is a biological treatment technology widely used in urban sewage treatment and industrial wastewater treatment, mainly used to remove pollutants such as organic matter, nitrogen, and phosphorus in sewage. The A / O process usually includes two main treatment stages: an anaerobic section (Anaerobic) and an aerobic section (Aerobic). In the anaerobic section (Anaerobic), under anaerobic conditions, microorganisms decompose complex organic matter in sewage into simple organic matter, and at the same time promote the release of phosphorus by polyphosphate-accumulating bacteria, creating conditions for phosphorus absorption in the subsequent aerobic section. The aerobic section (Aerobic) is a treatment section where, under aerobic conditions, sufficient oxygen is provided through aeration to promote the growth of microorganisms and the oxidative decomposition of organic matter. Therefore, the A / O process achieves efficient removal of organic matter, nitrogen, and phosphorus, and is an economical and effective biological treatment method in urban sewage treatment.

[0003] However, the A / O process also has some disadvantages. It has a large demand for oxygen, consumes a large amount of energy, and is affected by many factors such as fluctuations in influent water quality and operating costs. The removal effect of some refractory organic matter, phosphorus, nitrogen, and other soluble pollutants in sewage is still not ideal.

[0004] An aquatic plant planting matrix filler refers to a support and nutrient medium for cultivating aquatic plants, and it plays an important role in the aquatic plant ecosystem. The selection and use of the aquatic plant planting matrix filler directly affect the growth status of plants, the water purification effect, and the stability of the ecosystem.

[0005] Some researchers have proposed that sewage can be treated by combining an aquatic plant planting matrix filler on the basis of the A / O process. The aquatic plant planting matrix filler can provide a large amount of biological attachment area by forming biofilms on the surface and inside of the filler, which is beneficial to the attachment and growth of bacteria, algae, and other microorganisms. Microorganisms can decompose organic substances, absorb and transform nutrients, thereby playing a role in purifying water quality. At the same time, the roots of aquatic plants can also effectively further remove pollutants such as organic matter, nitrogen, and phosphorus in sewage through nutrient absorption and redox reactions, improving the sewage purification effect. However, the current technology is not yet perfect, so there is still a large room for improvement in the current water purification effect (removal rates of various pollutants). Summary of the Invention

[0006] In order to further improve the comprehensive sewage purification effect of the sewage treatment A / O process and the aquatic plant planting matrix filler, the present application provides an aquatic plant planting matrix filler for sewage treatment and its preparation method.

[0007] In the first aspect, the present application provides an aquatic plant planting matrix filler for sewage treatment. The raw materials used include the following components in parts by weight: 20-45 parts of iron oxide; 15-25 parts of aluminum oxide; 2-10 parts of calcium oxide; 5-15 parts of silicon dioxide; 1-10 parts of tourmaline powder; 15-50 parts of carbon material powder; 15-20 parts of Ca / Mg-biochar; 0.5-2 parts of binder; 10-50 parts of water; 0.1-1 part of titanium dioxide.

[0008] The preparation process of Ca / Mg-biochar is specifically as follows: The industrial recycled sludge is dried, ground, and sieved to obtain dry sludge. Subsequently, the dry sludge, calcium chloride, magnesium chloride, and water are uniformly mixed, heated, and stirred at a constant temperature. Precipitation occurs in an alkaline environment, followed by filtration, drying, grinding, pyrolysis, washing, and drying to obtain Ca / Mg-biochar.

[0009] By adopting the above technical solution, the present application uses a variety of substances for compounding, and the substances fully exert their synergistic effects, and finally an aquatic plant planting matrix filler with good sewage purification effect is obtained.

[0010] First of all, the present application uses industrial recycled sludge to prepare Ca / Mg-biochar through modification with metal compounds. It has more polar groups and metal oxides, which can play a role in spontaneous adsorption, complexation, ion exchange, and electrostatic attraction of nitrogen and phosphorus. Adding it to the aquatic plant planting matrix filler can significantly reduce the nitrogen and phosphorus content in the water body. Compared with ordinary biochar materials, Ca / Mg-biochar has more diverse ways to remove nitrogen and phosphorus, and thus has more excellent removal ability.

[0011] Secondly, the matrix filler can provide the iron element, calcium element, and aluminum element necessary for the growth and development of aquatic plants, and also provides silicon element that can enhance the disease resistance and stress resistance of aquatic plants, titanium element with certain antibacterial ability and can reduce the decay degree of the matrix filler, as well as a granular structure for aquatic plants to support and attach, so as to maintain the growth stability of aquatic plants. At the same time, this granular structure can also maintain the air permeability and water permeability of the matrix filler to a certain extent, helping to relieve the situation of waterlogging and hypoxia in the soil and further promoting the healthy growth of aquatic plants.

[0012] Finally, after various oxides, tourmaline powder, and carbon material powder in the matrix filler are mixed, they can exert certain adsorption and photocatalytic effects. When in use, they can exhibit good ability to assist in decomposing organic matter under light, inhibit the growth of algae in water, regulate the pH of the system, and provide appropriate trace elements for the growth of aquatic plants. This can not only significantly reduce the content of pollutants such as organic matter, nitrogen, and phosphorus in water, but also ensure the normal growth of aquatic plants. In the specific implementation manner of this application, the carbon material powder is activated carbon powder and the binder is silica sol, which is only for illustrative purposes, and those skilled in the art can adjust according to actual situations.

[0013] Generally speaking, the aquatic plant planting matrix filler of this application converts pollutants in water into nutrients required for the growth of aquatic plants through adsorption and degradation. The roots of aquatic plants further remove pollutants such as organic matter, nitrogen, and phosphorus in sewage through the absorption of nutrients and redox reactions, and have the functions of efficiently removing the content of organic matter, nitrogen, and phosphorus in sewage and promoting the healthy growth of aquatic plants. Experimental data proves that after inserting aquatic plants into the aquatic plant planting matrix filler of this application and then putting it into the aerobic section of the urban sewage treatment A / O system, the chemical oxygen demand removal efficiency can reach more than 90%, the biochemical oxygen demand removal efficiency can reach more than 85%, the total phosphorus removal rate can reach more than 90%, and the total nitrogen removal rate can reach more than 92%. At the same time, the root activity and plant height growth rate of aquatic plants both reach good growth indicators.

[0014] Preferably, in the preparation process of the Ca / Mg-biochar, the weight ratio of the dry sludge, calcium chloride, magnesium chloride, and water used is 10: (12 - 15): (30 - 35): 200.

[0015] Preferably, the weight ratio of the dry sludge, calcium chloride, magnesium chloride, and water is 10:13:33.5:200.

[0016] By adopting the above technical solution, this application strictly controls the weight ratio of the dry sludge, calcium chloride, magnesium chloride, and water used in the preparation process of the Ca / Mg-biochar, thereby controlling the calcium and magnesium content in the Ca / Mg-biochar and further optimizing the ability of the Ca / Mg-biochar to remove nitrogen and phosphorus.

[0017] Preferably, the raw materials used also include lanthanum-loaded diatomite.

[0018] Moreover, the preparation method of the lanthanum-loaded diatomite is specifically as follows: disperse diatomite in sodium hydroxide solution, heat and stir to obtain diatomite alkali solution. Then disperse lanthanum chloride in water to obtain lanthanum chloride solution. Mix the diatomite alkali solution and lanthanum chloride solution in equal volume, stir, stand, filter to obtain solid, wash, and dry to obtain lanthanum-loaded diatomite.

[0019] By adopting the above technical solution, the present application modifies diatomite with a lanthanum-containing compound, loads lanthanum element on the diatomite, and obtains lanthanum-loaded diatomite with a large number of coordination sites. Diatomite itself has a porous structure, which can improve the structure of the matrix filler, enhance the air permeability and adsorption capacity of the matrix filler, and promote the microbial activities in the system, thereby providing a more excellent environment for the growth of aquatic plants. The adsorption capacity of the treated diatomite is further improved. Therefore, the lanthanum-loaded diatomite can first significantly improve the root activity and plant height growth rate of aquatic plants, and can also effectively adsorb phosphorus in the water body by combining its own high adsorption capacity, significantly reducing the phosphorus content in the water body and comprehensively improving the overall water purification effect.

[0020] More importantly, compared with the adsorption of nitrogen, Ca / Mg-biochar is more active in the adsorption of phosphorus. Once the nitrogen and phosphorus contents in the water body are both large, the adsorption capacity of Ca / Mg-biochar for nitrogen will decrease. At this time, due to the addition of lanthanum-loaded diatomite, phosphorus in the water body can be quickly adsorbed by it. Even if the nitrogen and phosphorus contents in the water body are too large, Ca / Mg-biochar can still exert a balanced nitrogen and phosphorus adsorption effect. Therefore, Ca / Mg-biochar and lanthanum-loaded diatomite can exert a synergistic effect, further improving the nitrogen and phosphorus removal capacity of the aquatic plant planting matrix filler of the present application. It has been experimentally proved that at this time, the total phosphorus removal rate can reach more than 95.5%, and the total nitrogen removal rate can reach more than 96.7%.

[0021] Preferably, the addition amount of the lanthanum-loaded diatomite is 5-10 parts by weight.

[0022] By adopting the above technical solution, the present application strictly controls the addition amount of the lanthanum-loaded diatomite to be 5-10 parts by weight, which can exert a more excellent synergistic effect with Ca / Mg-biochar. At this time, its effect of promoting the growth of aquatic plants and the water purification effect of the overall matrix filler are both better.

[0023] Preferably, in the preparation method of the lanthanum-loaded diatomite, the weight ratio of diatomite to lanthanum chloride is 10:(2-3).

[0024] By adopting the above technical solution, the present application strictly controls the weight ratio of diatomite to lanthanum chloride in the preparation of the lanthanum-loaded diatomite. If the dosage of lanthanum chloride is too large, the purpose of effectively enhancing the adsorption effect cannot be achieved; if the dosage of lanthanum chloride is too large, it needs to be in a certain alkaline environment to exert a higher adsorption effect. However, the pH value of the sewage water body generally cannot reach the alkalinity required to meet its effective requirements. Therefore, the present application controls the weight ratio of the two within a certain range to optimize the adsorption effect of the lanthanum-loaded diatomite added to the matrix filler used in the sewage treatment environment of the present application.

[0025] Second aspect, the present application provides a preparation method for an aquatic plant planting matrix filler for sewage treatment, comprising the following steps: mixing the raw materials used, grinding the average fineness to 180 - 200 mesh, then rolling into a planting blank, distributing holes, firing, and obtaining the aquatic plant planting matrix filler after natural cooling.

[0026] Preferably, the firing temperature is 700 - 1600 °C, and the firing time is 48 - 75 h.

[0027] By adopting the above technical solution, the present application mixes the raw materials used, grinds them, rolls them into a planting blank, forms a certain shape, provides a basis for subsequent processing and use. Subsequently, holes are distributed, providing a good environment for the fixation and growth of aquatic plants, reducing the possibility of aquatic plants lodging during the water purification process. Firing can enhance the mechanical strength and stability of the matrix filler, improve the pore structure of the matrix filler, and improve the biological adsorption capacity of the matrix filler. Finally, natural cooling can reduce the influence of internal stress and cracks generated due to temperature reduction inside the matrix filler, and finally obtain an aquatic plant planting matrix filler with a certain stability and suitable for the growth of aquatic plants.

[0028] Moreover, the present application grinds the raw materials used and controls the firing temperature and time, so that the matrix filler is uniformly fired, and then a more uniform pore structure is formed, thereby improving the air permeability and water permeability of the matrix filler, the biological adhesion ability of the filler, and killing the microorganisms and harmful substances in the matrix filler as much as possible, reducing the biological pollution of the matrix filler, and being more conducive to the root attachment and good growth of aquatic plants.

[0029] Preferably, the planting blank is rolled in layers, and a sealing layer is laid between each layer of the planting blank. The sealing layer comprises fly ash and straw powder with a weight ratio of 1:(0.2 - 1).

[0030] Specifically, the raw materials used are evenly divided into several equal parts, rolled one by one, assembled. When assembling, each time a layer of the planting blank is placed, a sealing layer is laid above the planting blank. After laying, repeat the above steps of rolling and laying until the raw materials are used up, and lay the last sealing layer, then holes can be distributed, fired, and cooled to obtain the aquatic plant planting matrix filler.

[0031] By adopting the above technical solution, the raw materials used in this application are evenly divided into several equal parts, and a sealing layer is laid every time a planting blank is prepared. The fly ash and straw powder in the sealing layer can exert a synergistic effect, absorb and utilize the oxygen in the closed space during the firing process, so that the firing process is in an oxygen-deficient atmosphere, and at the same time, it can inhibit the heat loss during firing, reduce the temperature difference between the inside and outside of the planting blank, and is conducive to the uniform shrinkage of the planting blank and the reduction of metal oxides in the matrix filler, improving the firing quality, thereby improving the mechanical strength and stability of the matrix filler. In the specific implementation manner of this application, the raw materials used are evenly divided into four equal parts for preparation, which is only for illustrative purposes, and those skilled in the art can adjust according to the actual situation.

[0032] In the third aspect, this application provides an application of an aquatic plant planting matrix filler for sewage treatment. The aquatic plants are planted into the holes of the aquatic plant planting matrix filler, then placed in the aerobic section of the A / O process, and finally sewage treatment is carried out.

[0033] By adopting the above technical solution, the matrix filler of this application cooperates with the A / O process, and can efficiently remove the organic matter, nitrogen and phosphorus content in the sewage, further improving the comprehensive sewage purification effect of the A / O process for sewage treatment and the aquatic plant planting matrix filler. The aquatic plants in this application take reeds and cattails as examples, which are only for illustrative purposes, and those skilled in the art can adjust according to the actual situation.

[0034] In summary, this application has the following beneficial technical effects: 1. In the aquatic plant planting matrix filler of this application, the substances fully exert a synergistic effect, convert the pollutants in the water body into nutrients required for the growth of aquatic plants through adsorption and degradation, and the roots of the aquatic plants further remove pollutants such as organic matter, nitrogen and phosphorus in the sewage through the absorption of nutrients and redox reactions, which has the functions of efficiently removing the organic matter, nitrogen and phosphorus content in the sewage and promoting the healthy growth of aquatic plants; 2. The preparation method of this application optimizes each step and conducts sealed firing, so that the obtained aquatic plant planting matrix filler has higher mechanical strength and stability, thereby improving the sewage purification stability of the matrix filler of this application; 3. The aquatic plant planting matrix filler for sewage treatment of this application cooperates with the A / O process, and can efficiently remove the organic matter, nitrogen and phosphorus content in the sewage, further improving the comprehensive sewage purification effect of the A / O process for sewage treatment and the aquatic plant planting matrix filler. Specific Embodiment

[0035] Material Source Unless otherwise specified, the raw materials used in this application are all commercially available products, specifically: Industrial recycled sludge with a moisture content of 67.11% ± 1.66%, an ash content of 51.15% ± 1.35%, and a volatile solid content of 48.85% ± 1.40%. Elemental composition (%): C 35.1, H 3.61, O 28.4, N 11, Si 6.85, Fe 3.69, P 1.81, Al 1.48, Ca 1.19, Mg 0.64, S 0.64, K 0.59, Na 0.26, Mn 0.13, Ti 0.13, Zn 0.04; Diatomite, main chemical components (%): SiO2 90.66, Fe2O3 2.96, Al2O3 4.28, K2O 0.67, P2O5 0.43; Lanthanum chloride, purchased from Hubei Xinghengye Technology Co., Ltd.; Iron oxide, aluminum oxide, calcium oxide, silicon dioxide, and titanium dioxide were all purchased from Wujiang Yongsheng Chemical Co., Ltd.; Tourmaline powder was purchased from Lingshou Shifeng Mining Processing Factory, with a particle size of 325 mesh; Activated carbon was purchased from Wuxi Maohong Activated Carbon Co., Ltd., with an iodine adsorption value of 900 - 1100 mg / g; Silica sol was purchased from Yantai Hengxin Chemical Technology Co., Ltd.; Fly ash was purchased from Lingshou Aohong Mineral Products Business Department, with a moisture content ≤ 5 wt% Straw powder was provided by straw from Zhumadian Youmu Straw Processing Co., Ltd. and used after being pulverized to 200 mesh.

[0036] The present application will be further described in detail below in combination with preparation examples, examples, application examples, and comparative examples.

[0037] Preparation Examples 1 - 8 Preparation method of Ca / Mg - biochar, including the following steps: Place the industrial recycled sludge in an oven at 105°C for drying, grind it evenly with a pulverizer, and pass through a 250 - μm sieve to obtain dry sludge. Subsequently, uniformly mix the dry sludge, calcium chloride, magnesium chloride, and water. The specific dosages are shown in Table 1.1. Heat the system to 60°C, keep it at a constant temperature, stir at a speed of 120 r / min for 1 h, then add NaOH / Na2CO3 buffer solution to adjust the pH = 10, and precipitate for 12 h in this alkaline environment. Filter, dry, grind, transfer to a tubular furnace under nitrogen protection, heat it at a heating rate of 10°C / min to 600°C, keep it at a constant temperature for pyrolysis for 120 min, stop heating, wait for the system temperature to drop to room temperature, then wash and dry until the system reaches a constant weight to obtain Ca / Mg - biochar.

[0038] Table 1.1 Dosages of substances in Preparation Examples 1 - 8 (kg)

[0039] Preparation Examples 9-13 The preparation method of lanthanum-loaded diatomaceous earth comprises the following steps: Diatomaceous earth was dispersed in 90 L of 6 mol / L sodium hydroxide solution and magnetically stirred in a 60 ° C water bath for 2 h to obtain diatomaceous earth alkali solution. Lanthanum chloride was then dispersed in 90 L of water and stirred at room temperature for 24 h to obtain lanthanum chloride solution, wherein the amount of diatomaceous earth and lanthanum chloride was shown in Table 1.2. Then all the diatomaceous earth alkali solution and all the lanthanum chloride solution were blended and allowed to stand for 24 hours. The solid was separated and washed with deionized water until neutral, and then vacuum dried at 60 ° C for 12 h to obtain lanthanum-loaded diatomaceous earth.

[0040] Table 1.2 Amount of substances used in Preparation Examples 9-13 (kg)

[0041] Comparative Preparation Example 1 The preparation method of Mg-biochar comprises the following steps: The industrial recycled sludge was placed in an oven at 105°C and dried, ground evenly using a crusher, and passed through a 250um sieve to obtain dry sludge. Subsequently, 10kg of dry sludge, 45kg of magnesium chloride and water were evenly mixed, and the system was heated to 60°C, kept constant temperature, and stirred at a speed of 120r / min for 1h. Subsequently, NaOH / Na2CO3 buffer was added to adjust the pH to 10, and precipitated in this alkaline environment for 12h, filtered, dried, ground, and transferred to a tubular furnace under nitrogen protection. The temperature was increased to 600°C at a heating rate of 10°C / min, and pyrolysis was carried out at a constant temperature for 120min. The heating was stopped, and the system temperature was washed after it dropped to room temperature, and dried to a constant weight to obtain Mg-biochar.

[0042] Comparative Preparation Example 2 The preparation method of Ca-biochar comprises the following steps: The industrial recycled sludge was placed in an oven at 105°C and dried, ground evenly using a crusher, and passed through a 250um sieve to obtain dry sludge. Subsequently, 10kg of dry sludge, 45kg of calcium chloride and water were evenly mixed, and the system was heated to 60°C, kept constant temperature, and stirred at a speed of 120r / min for 1h. Subsequently, NaOH / Na2CO3 buffer was added to adjust the pH to 10, and precipitated in this alkaline environment for 12h, filtered, dried, ground, and transferred to a tubular furnace under nitrogen protection. The temperature was increased to 600°C at a heating rate of 10°C / min, and pyrolysis was carried out at a constant temperature for 120min. The heating was stopped, and the system temperature was washed after it dropped to room temperature, and dried to a constant weight to obtain Ca-biochar.

[0043] Examples 1.1-1.5 A preparation method of an aquatic plant planting matrix filler for sewage treatment, comprising the following steps: According to the dosages in Table 2.1, mix all the raw materials used and stir evenly, then grind them to an average fineness of 180 mesh, 200 mesh, 190 mesh, 180 mesh, and 200 mesh respectively, put them into a pressing device and roll them into planting blanks with evenly distributed holes to ensure that the planting density of aquatic plants is 10 plants / m 2 , and then put them into a refractory container, fire them at 650 °C for 80 h, and obtain an aquatic plant planting matrix filler with a height of 0.8 ± 0.005 m after natural cooling.

[0044] Table 2.1 Dosages of various substances in Examples 1.1 - 1.5 (kg)

[0045] Examples 2.1 - 2.7 A preparation method of an aquatic plant planting matrix filler for sewage treatment, which is different from Example 1.3 in that the Ca / Mg-biochar prepared in Preparation Example 1 is respectively replaced with the Ca / Mg-biochar prepared in Preparation Examples 2 - 8, and the rest are the same as Example 1.3.

[0046] Examples 3.1 - 3.5 A preparation method of an aquatic plant planting matrix filler for sewage treatment, which is different from Examples 1.1 - 1.5 in that the Ca / Mg-biochar prepared in Preparation Example 1 is respectively replaced with the lanthanum-loaded diatomite prepared in Preparation Example 9, and the rest are the same as Examples 1.1 - 1.5.

[0047] Examples 4.1 - 4.5 A preparation method of an aquatic plant planting matrix filler for sewage treatment, which is different from Example 1.3 in that 7.5 kg of the lanthanum-loaded diatomite prepared in Preparation Examples 9 - 13 are also respectively added, and the rest are the same as Example 1.3.

[0048] Examples 4.6 - 4.9 A preparation method of an aquatic plant planting matrix filler for sewage treatment, which is different from Example 1.3 in that 2.5 kg, 5 kg, 10 kg, and 12.5 kg of the lanthanum-loaded diatomite prepared in Preparation Example 12 are also respectively added, and the rest are the same as Example 1.3.

[0049] Examples 5.1 - 5.4 A preparation method of an aquatic plant planting matrix filler for sewage treatment, which is different from Example 1.3 in that the firing temperature and time are different, as shown in Table 2.2 specifically, and the rest are the same as Example 1.3.

[0050] Table 2.2 Firing process parameters of Examples 5.1 - 5.4

[0051] Examples 6.1 - 6.5 A preparation method of an aquatic plant planting matrix filler for sewage treatment, different from Example 1.3 in that the planting blank is rolled in layers, and a sealing layer is laid between each layer of planting blank, specifically: After mixing and stirring all the raw materials used evenly, grind them to an average fineness of 190 meshes, and divide them into four equal parts. First, put the four equal parts of the raw materials into a pressing device and roll them into four layers of planting blanks. Then, lay fly ash and / or straw powder on the upper surface of one layer of the planting blank. The specific laying composition is shown in Table 2.3 until the laying thickness reaches 2 cm to obtain the sealing layer. Subsequently, place the second layer of planting blank on the upper surface of the sealing layer, lay the sealing layer, place the third layer of planting blank, lay the sealing layer, place the fourth layer of planting blank, place the sealing layer, and then evenly distribute holes to ensure that the planting density of aquatic plants is 10 plants / m 2 , and then put the whole material into a refractory container, fire it at 650 °C for 80 h, and obtain the aquatic plant planting matrix filler after natural cooling.

[0052] Table 2.3 Specific substances and ratios of the sealing layer of Examples 6.1 - 6.5

[0053] Comparative Examples 1 - 5 Different from Example 1.3, in Comparative Examples 1 - 2, the dosages of the raw materials used are different from those in Example 1.3, and in Comparative Examples 3 - 5, the components of the raw materials used are different from those in Example 1.3, as shown in Table 2.4 specifically, and the rest are the same as those in Example 1.3.

[0054] Table 2.4 Components and dosages (kg) of various substances in Comparative Examples 1 - 5

[0055] Comparative Example 6 Different from Example 1.3, after mixing and stirring all the raw materials used evenly, grind them to an average fineness of 150 meshes, and the rest are the same as those in Example 1.3.

[0056] Comparative Example 7 Different from Example 1.3, after mixing and stirring all the raw materials used evenly, grind them to an average fineness of 200 meshes, and the rest are the same as those in Example 1.3.

[0057] Application Examples 1 - 35 Reeds and cattails were respectively planted into the holes of the aquatic plant planting substrate fillers in Examples 1.1 - 6.5 according to the plant number ratio of 1:1, and then were respectively placed into the aerobic section of the A / O process. The hydraulic retention time was set to 1 d, and finally sewage treatment was started. The specific indexes of the influent water quality are shown in Table 3.

[0058] Comparative Application Examples 1 - 7 Reeds and cattails were respectively planted into the holes of the aquatic plant planting substrate fillers in Comparative Examples 1 - 7 according to the plant number ratio of 1:1, and then were respectively placed into the aerobic section of the A / O process. The hydraulic retention time was set to 1 d, and finally sewage treatment was started. The specific indexes of the influent water quality are shown in Table 3.

[0059] Table 3. Specific indexes of influent water quality (mg / L)

[0060] Performance Detection 1. Detection of water purification ability: The indexes of the effluent water quality of each application example were determined according to the records in GB 8978 - 2002, the removal rates were calculated, and the results were recorded in Table 4. The water purification result of the aerobic section of the ordinary A / O process (without placing the aquatic plant planting substrate filler, hydraulic retention time 1 d) was used as the blank control group, with a COD removal rate of 72.5%, a BOD5 removal rate of 68.5%, a total phosphorus removal rate of 71.0%, and a total nitrogen removal rate of 74.5%; 2. Detection of stability: The cylinder compressive strength of the aquatic plant planting substrate fillers prepared in each example was determined according to the records in GB / T 17431.1, and the results were recorded in Table 5; 3. Monitoring of the growth situation of aquatic plants: 3a. Plant growth traits: The plant heights of reeds and cattails were measured with a scale, and the plant height growth rate (30 days) was calculated. The plant height growth rate (cm·d -1 ) = (H1 - H0) / t, where H0 is the initial plant height / cm, H1 is the plant height / cm after 30 days, and t = 30 days; 3b. Root activity: Weigh 1 g of washed reed roots and 1 g of cattail roots respectively, put them into two different Erlenmeyer flasks, and add 25 mL of 50 μg / mL α-naphthylamine and 25 mL of phosphate buffer to both flasks. After standing for 10 min, take 2 mL of solution from each flask (the first sampling). Stopper the remaining solutions and place them on an oscillator, shake at 25 °C for 3 - 6 h. After completion, take 2 mL of solution (the second sampling), and conduct a blank experiment without roots. Add 10 mL of distilled water to the 2 mL of the determination solution taken for the two samplings and the two blanks, mix well, add 1 mL of 1% sulfanilic acid and 1 mL of 100 μg / L sodium nitrite, mix well and let it develop color for 5 min. Add distilled water to make up to 20 mL, mix well and measure the absorbance at 520 nm with a spectrophotometer. The calculation formula for plant root activity is as follows: A1 = (X1 - X2) × V / V a , A2 = (C1 - C2) × V / V a , the bio-oxidation intensity of α-naphthylamine (μg / g·h) = (A1 - A2) / T × W, where X1 is the measured value of the first sampling (μg), X2 is the measured value of the second sampling (μg), C1 is the measured value of the first blank (μg), C2 is the measured value of the second blank (μg), V is the total volume of the extraction solution during measurement (mL), V a is the volume of the extraction solution used during measurement (mL), T is the reaction time (h), W is the fresh weight of the roots (g). Record the bio-oxidation intensity of α-naphthylamine (μg / g·h) in Table 5.

[0061] Table 4 Pollutant removal rate

[0062] Table 5 Stability of matrix fillers and growth status of aquatic plants

[0063] Data analysis: As can be seen from Table 4-5, the COD removal rates of Application Examples 1-5 were 91.4-91.6%, the BOD5 removal rates were 85.2-85.5%, the total phosphorus removal rates were 90.2-91.1%, and the total nitrogen removal rates were 92.5-93.0%. There was a significant improvement compared to the blank group. Moreover, the cylinder compressive strength of Examples 1.1-1.5 could reach 7.5-7.9 MPa, the reed plant height growth rate of Application Examples 1-5 could reach 1.07-1.09%, the cattail plant height growth rate could reach 1.44-1.46%, the α-naphthylamine biological oxidation intensity of reed could reach 26.1-26.3 ug / g·h, and the α-naphthylamine biological oxidation intensity of cattail could reach 51.2-51.4 ug / g·h. It was proved that the aquatic plant planting matrix filler of this application converted the pollutants in the water body into nutrients required for the growth of aquatic plants through adsorption and degradation. The roots of aquatic plants further removed pollutants such as organic matter, nitrogen, and phosphorus in the sewage through nutrient absorption and redox reactions, which not only had the effect of efficiently removing the organic matter, nitrogen, and phosphorus content in the sewage but also promoted the healthy growth of aquatic plants. At the same time, it also had a certain mechanical strength and stability; The difference in Application Examples 6-12 was that different Ca / Mg-biochars prepared by different preparation examples were used in the matrix filler. Among them, the total nitrogen removal rate and total phosphorus removal rate of Application Example 10 were significantly higher than those of other application examples, which proved that this application controlled the weight ratio of dry sludge, calcium chloride, magnesium chloride, and water used in the preparation process of Ca / Mg-biochar, thereby controlling the calcium and magnesium contents in Ca / Mg-biochar and further optimizing the nitrogen and phosphorus removal ability of Ca / Mg-biochar; The difference in Application Examples 13-17 was that Ca / Mg-biochar was replaced by lanthanum-loaded diatomite. Its COD removal rate, BOD5 removal rate, total phosphorus removal rate, total nitrogen removal rate, reed plant height growth rate, cattail plant height growth rate, α-naphthylamine biological oxidation intensity of reed, and α-naphthylamine biological oxidation intensity of cattail were still at a relatively high level and were basically the same as those of Application Examples 1-5 respectively, which proved that the lanthanum-loaded diatomite of this application could indeed improve the structure of the matrix filler, enhance the air permeability and adsorption ability of the matrix filler, promote the microbial activities in the system, and thus provide a better environment for the growth of aquatic plants; The difference in Application Examples 18-22 was that lanthanum-loaded diatomite was further added on the premise that Ca / Mg-biochar had already been added to the system. It was found that its COD removal rate, BOD5 removal rate, total phosphorus removal rate, and total nitrogen removal rate were significantly improved compared to Application Example 3, which proved that Ca / Mg-biochar and lanthanum-loaded diatomite of this application could play a very significant synergistic effect and further improve the nitrogen and phosphorus removal ability of the aquatic plant planting matrix filler of this application; Among them, the improvement ranges of the COD removal rate, BOD5 removal rate, total phosphorus removal rate, and total nitrogen removal rate in Application Examples 19-21 are greater than those in other application examples, which proves that by strictly controlling the weight ratio of diatomite to lanthanum chloride in the preparation of lanthanum-loaded diatomite, the adsorption effect of the lanthanum-loaded diatomite added to the matrix filler used in the sewage treatment environment of this application is optimized; The difference between Application Examples 23-26 and Application Example 21 lies in the different addition amounts of the lanthanum-loaded diatomite prepared in Preparation Example 12. Among them, the COD removal rate, BOD5 removal rate, total phosphorus removal rate, and total nitrogen removal rate in Application Example 21 and Application Examples 24-25 are significantly higher than those in Application Example 23 and Application Example 26, which proves that by controlling the addition amount of the lanthanum-loaded diatomite, a more excellent cooperative effect can be exerted with Ca / Mg-biochar. At this time, its effect of promoting the growth of aquatic plants and the water purification effect of the overall matrix filler are both better; The differences between Application Examples 27-30 lie in the different firing temperatures and times. Among them, the reed plant height growth rate, cattail plant height growth rate, α-naphthylamine biological oxidation intensity of reed, and α-naphthylamine biological oxidation intensity of cattail in Application Examples 27-29 are also higher than those in Application Example 3 and Application Example 30, which proves that by controlling the firing temperature and time within a certain range, the matrix filler can be uniformly fired, thereby forming a more uniform pore structure, improving the air permeability and water permeability of the matrix filler, the biological attachment ability of the filler, and killing the microorganisms and harmful substances in the matrix filler as much as possible, reducing the biological pollution of the matrix filler, and being more conducive to the root attachment and good growth of aquatic plants; The differences between Application Examples 31-35 lie in that the planting blank is laminated and rolled, and a sealing layer is laid between each layer of the planting blank. And the cylinder compressive strength of Application Examples 31-34 is significantly higher than that of Application Example 3, and the reed plant height growth rate, cattail plant height growth rate, α-naphthylamine biological oxidation intensity of reed, and α-naphthylamine biological oxidation intensity of cattail are also higher than those of Application Example 3. However, the plant height growth rate and root activity of Application Example 34 are significantly inferior to those of Application Example 3, and the cylinder compressive strength of Application Example 35 is also significantly lower than that of Application Examples 31-33, which proves that the fly ash and straw powder in the sealing layer of this application can exert a cooperative effect, absorb and utilize the oxygen in the closed space during the firing process, make the firing process in an oxygen-deficient atmosphere, and at the same time can inhibit the heat dissipation during firing, reduce the temperature difference between the inside and outside of the planting blank, be conducive to the uniform shrinkage of the planting blank and the reduction of metal oxides in the matrix filler, improve the firing quality, and thus improve the mechanical strength and stability of the matrix filler; The COD removal rate, BOD5 removal rate, total phosphorus removal rate, and total nitrogen removal rate of Comparative Application Examples 1-2 are significantly lower than those of Application Example 3, which proves that the material ratio of this application can more fully exert the cooperative effect between various substances and can significantly reduce the contents of pollutants such as organic matter, nitrogen, and phosphorus in the water body; The COD removal rate, BOD5 removal rate, total phosphorus removal rate, and total nitrogen removal rate of Comparative Application Examples 3-5 are significantly lower than those of Application Example 3, which proves that calcium and magnesium in the Ca / Mg-biochar of the present application have a good synergistic effect. This material has more polar groups and metal oxides, which can play roles of spontaneous adsorption, complexation, ion exchange, and electrostatic attraction on nitrogen and phosphorus. When added to the substrate filler for aquatic plant cultivation, it can significantly reduce the nitrogen and phosphorus content in the water body. Compared with ordinary biochar materials, Ca / Mg-biochar has more diverse ways to remove nitrogen and phosphorus, and thus has more excellent removal ability. The difference between Comparative Application Examples 6-7 lies in the different particle sizes of the products obtained during grinding. Their water purification effects, mechanical strengths, and the root attachment and good growth of aquatic plants are all poor, which proves that grinding the raw materials used in the present application can enable the substrate filler to be uniformly fired, thereby forming a more uniform pore structure, improving the air permeability and water permeability of the substrate filler, the bioattachment ability of the filler, and killing the microorganisms and harmful substances in the substrate filler as much as possible, reducing the biological pollution of the substrate filler, and being more conducive to the root attachment and good growth of aquatic plants.

[0064] The embodiments of this specific implementation manner are all preferred embodiments of the present application, and do not limit the protection scope of the present application accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application should be covered within the protection scope of the present application.

Claims

1. An aquatic plant planting substrate filler for sewage treatment, characterized in that, The raw materials used include the following components in parts by weight: 20 - 45 parts of iron oxide; 15 - 25 parts of aluminum oxide; 2 - 10 parts of calcium oxide; 5 - 15 parts of silicon dioxide; 1 - 10 parts of tourmaline powder; 15 - 50 parts of carbon material powder; 15 - 20 parts of Ca / Mg - biochar; 0.5 - 2 parts of binder; 10 - 50 parts of water; 0.1 - 1 part of titanium dioxide.

2. The aquatic plant planting matrix filler for sewage treatment according to claim 1, wherein In the preparation process of the Ca / Mg - biochar, the weight ratio of the dry sludge, calcium chloride, magnesium chloride and water used is 10:(12 - 15):(30 - 35):

200.

3. The aquatic plant planting matrix filler for sewage treatment according to claim 2, characterized in that The weight ratio of the dry sludge, calcium chloride, magnesium chloride and water is 10:13:33.5:

200.

4. The aquatic plant planting matrix filler for sewage treatment according to claim 1, characterized in that, The raw materials used also include lanthanum - loaded diatomite.

5. The aquatic plant planting matrix filler for sewage treatment according to claim 4, characterized in that, The addition amount of the lanthanum - loaded diatomite is 5 - 10 parts by weight.

6. The aquatic plant planting matrix filler for sewage treatment according to claim 4, characterized in that In the preparation method of the lanthanum - loaded diatomite, the weight ratio of diatomite to lanthanum chloride is 10:(2 - 3).

7. A preparation method of the aquatic plant planting matrix filler for sewage treatment according to any one of claims 1-6, characterized in that, It includes the following steps Mix the raw materials used, grind the average fineness to 180 - 200 meshes, then roll them into planting green bodies, distribute holes, fire them, and obtain the aquatic plant planting matrix filler after natural cooling.

8. The preparation method of the aquatic plant planting matrix filler for sewage treatment according to claim 7, characterized in that, The firing temperature is 700 - 1600 °C, and the firing time is 48 - 75 h.

9. The preparation method of the aquatic plant planting matrix filler for sewage treatment according to claim 8, characterized in that, The planting green body is rolled in layers, and a sealing layer is laid between each layer of planting green bodies. The sealing layer includes fly ash and straw powder with a weight ratio of 1:(0.2 - 1).

10. Application of an aquatic plant planting matrix filler for sewage treatment, characterized in that, Plant the aquatic plants into the holes of the aquatic plant planting matrix filler, then put them into the aerobic section of the A / O process, and finally carry out sewage treatment.

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