Phosphorus adsorption bottom mud ceramsite for recycling riverway as well as preparation method and application of phosphorus adsorption bottom mud ceramsite

Abstract

The invention provides a preparation method of phosphorus adsorption bottom mud ceramsite for recycling river channels, which comprises the following steps: uniformly mixing dredged bottom mud, domestic sludge and fly ash according to a certain proportion, adding water, stirring and granulating to prepare raw ceramsite, and drying; the adding proportion of the dredged sediment is 24.3 wt%-96.3 wt%, the adding proportion of the domestic sludge is 0 wt%-32.6 wt%, and the adding proportion of the fly ash is 3.71 wt%-52 wt%; and sintering the dried raw ceramsite, and cooling to obtain the ceramsite. The invention also discloses the phosphorus adsorption bottom mud ceramsite prepared by adopting the method, and application of the phosphorus adsorption bottom mud ceramsite in wastewater phosphorus removal and application of the phosphorus adsorption bottom mud ceramsite in river channel water body phosphorus removal. According to the scheme, a new thought is provided for disposal of dredged bottom mud, domestic sludge and fly ash waste, the influence of the raw materials on the phosphorus adsorption capacity and the porosity is more accurately studied from the raw material components, and the ceramsite adsorbent with excellent performance is obtained.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of water treatment, and relates to a phosphorus-adsorbing bottom mud ceramsite for river reuse, its manufacturing method and application. Background Art

[0002] In recent years, eutrophication has become a serious problem in many rivers and lakes. A large amount of phosphorus in eutrophic water bodies causes a large number of algae to multiply, and the long-term lack of oxygen in the water leads to the death of a large number of animals and plants in the water, seriously affecting the water environment. In response to the problem of water body eutrophication, making ceramsite with low price and wide application range as a backfill material is a feasible solution for treating water body eutrophication.

[0003] Ceramsite has been widely used as a medium for sewage treatment and applied in the construction field because of its low price, high compressive strength and other excellent characteristics. High-quality ceramsite can not only adsorb a large amount of phosphorus in water, but also its high porosity can provide a good habitat for microorganisms, while increasing the dissolved oxygen in the water and thus reducing the risk of eutrophication.

[0004] In the content disclosed in Chinese Patent Publication No. CN109603734A "Phosphorus Adsorbent Based on River Bottom Mud and Its Application in Reusing River Water Body Treatment" and Chinese Patent Publication No. CN110064359A "Fly Ash-Bottom Mud Ceramsite for Purifying Eutrophic Water Body, Its Manufacturing Method and Application", dredging is one of the main means for treating eutrophic water bodies, and dredged bottom mud is the waste generated and needs to be treated. In addition, the rapid development of industry has also generated a large amount of domestic sewage sludge, fly ash and other waste with large quantity and complex composition. Reasonably and safely disposing of these solid wastes has become a difficult problem. Summary of the Invention

[0005] A brief overview of the present disclosure is given below to provide a basic understanding of certain aspects of the present disclosure. It should be understood that this overview is not an exhaustive overview of the present disclosure. It is not intended to identify the key or important parts of the present disclosure, nor is it intended to limit the scope of the present disclosure. Its purpose is only to present certain concepts in a simplified form as a prelude to a more detailed description to be discussed later.

[0006] The purpose of the present invention is to provide a phosphorus-adsorbing bottom mud ceramsite for river reuse, its manufacturing method and application. The ceramsite is suitable for treating eutrophic water bodies and can simultaneously dispose of different solid wastes such as dredged bottom mud, domestic sewage sludge and fly ash.

[0007] To solve the above technical problems, the technical solution provided by the present disclosure is:

[0008] In the first aspect, the present disclosure provides a manufacturing method of a phosphorus-adsorbing bottom mud ceramsite for river reuse, including:

[0009] Mix a certain proportion of dredged sediment, domestic sewage sludge, and fly ash evenly, add water and stir to granulate to obtain green ceramsite, and then perform drying treatment; the addition proportion of the dredged sediment is 24.3 wt% - 96.3 wt%, the addition proportion of the domestic sewage sludge is 0 wt% - 32.6 wt%, and the addition proportion of the fly ash is 3.71 wt% - 52 wt%.

[0010] Sinter the dried green ceramsite and obtain the ceramsite after cooling.

[0011] In the above method for manufacturing the phosphorus-adsorbing bottom sediment ceramsite for river reuse, as a preferred embodiment, the particle size of the green ceramsite is 3 mm - 8 mm (such as 3.5 mm, 4 mm, 5 mm, 6 mm, 7 mm, 7.5 mm, etc.); more preferably 5 mm ± 0.5 mm.

[0012] In the above method for manufacturing the phosphorus-adsorbing bottom sediment ceramsite for river reuse, as a preferred embodiment, the addition proportion of the dredged sediment is 54.91 wt% - 96.30 wt% (such as 60 wt%, 70 wt%, 80 wt%, 90 wt%, 95 wt%, etc.). The inventor observed that the phosphorus adsorption capacity of the ceramsite is mainly affected by the addition proportion of the dredged sediment, and as the addition proportion of the dredged sediment increases, the phosphorus adsorption capacity of the ceramsite increases. Because the main components of the dredged sediment are inorganic components such as silicon dioxide and alumina, which are crystalline aluminosilicate minerals with stacked silicon dioxide - alumina tetrahedral layers, forming a stable three-dimensional microporous structure, having a large specific surface area and high ion exchange capacity. The large specific surface area provides more adsorption sites. Therefore, the dredged sediment can significantly improve the adsorption and phosphorus removal effect of the solid waste ceramsite. In order to maximize the phosphorus adsorption capacity of the ceramsite, the optimal addition proportion of the dredged sediment is 54.91% - 96.30%.

[0013] In the above - mentioned method for making phosphorus - adsorbing bottom - mud ceramsite for reuse in river channels, as a preferred embodiment, the addition ratio of the domestic sludge is 13.39 wt% - 32.69 wt% (such as 15 wt%, 18 wt%, 20 wt%, 25 wt%, 28 wt%, 32 wt%, etc.), and the addition ratio of the fly ash is 4.39 wt% - 51.93 wt% (such as 6 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 45 wt%, etc.). The inventor observed that the porosity of the ceramsite is mainly affected by the addition ratios of the domestic sludge and the fly ash. With the increase in the addition ratio of the domestic sludge, the porosity of the ceramsite shows a trend of first increasing and then decreasing. Because the loss - on - ignition ratio of the domestic sludge is 18.91% and it contains a large amount of Fe2O3, the organic matter in the domestic sludge is carbonized to form gas, and at the same time reacts with Fe2O3 to release a large amount of gas, which is beneficial to the formation of interconnected pores. However, when the addition ratio of the domestic sludge is too high, it will lead to a corresponding increase in the residual carbon in the sintering stage, resulting in an increase in the expansion gas, ultimately crushing the sphere and reducing the porosity. With the increase in the addition ratio of the fly ash, the porosity of the ceramsite shows a gradually increasing trend because the fly ash contains a large amount of Al2O3, which is easy to generate a liquid phase under the action of high temperature and a flux, and a complex pore structure is formed under the condition of high - temperature liquid - phase sintering. Finally, it is found that when the addition ratio of the domestic sludge is 13.39% - 32.69% and the addition ratio of the fly ash is between 4.39% - 51.93%, the porosity of the ceramsite is between 40% - 50%, reaching the maximum value. However, with the increase in the addition ratio of the dredged bottom mud, the porosity of the ceramsite gradually decreases.

[0014] In the above - mentioned method for making phosphorus - adsorbing bottom - mud ceramsite for reuse in river channels, as a preferred embodiment, the addition ratio of the dredged bottom mud is 48 - 82%, the addition ratio of the domestic sludge is 8 - 18%, and the addition ratio of the fly ash is 3 - 40%;

[0015] More preferably, the addition ratio of the dredged bottom mud is 60 - 62%, the addition ratio of the domestic sludge is 13 - 15%, and the addition ratio of the fly ash is 24 - 26%;

[0016] Furthermore, the addition ratio of the dredged bottom mud is 61.41%, the addition ratio of the domestic sludge is 14.39%, and the addition ratio of the fly ash is 24.20%.

[0017] In the method for manufacturing the phosphorus-adsorbing bottom mud ceramsite for the reuse channel described above, as a preferred embodiment, the sintering treatment includes: preheating at 380 - 420°C for 12 - 18 minutes first, then increasing the heating temperature at a heating rate of 8 - 12°C / min, and then sintering at 1050 - 1150°C for 6 - 10 minutes; more preferably, preheating at 400°C for 15 minutes first, then increasing the heating temperature at a heating rate of 10°C / min, and then sintering at 1100°C for 8 minutes.

[0018] In the second aspect, the present disclosure also provides a phosphorus-adsorbing bottom mud ceramsite for the reuse channel, which is prepared by the above manufacturing method.

[0019] Preferably, the phosphorus adsorption amount of the ceramsite is 0.6 - 0.82 mg / g, and the porosity is 39% - 52%.

[0020] In the third aspect, the present disclosure also provides an application of the above phosphorus-adsorbing bottom mud ceramsite for the reuse channel in any one of the following (1) - (2):

[0021] (1) Application in wastewater phosphorus removal;

[0022] (2) Application in phosphorus removal from river channel water bodies.

[0023] Compared with the prior art, the beneficial effects of the present disclosure include but are not limited to:

[0024] 1. The present disclosure provides a method for preparing a phosphorus-adsorbing bottom mud ceramsite for the reuse channel using dredged bottom mud, domestic sewage sludge, and fly ash as raw materials, providing a new idea for the disposal of dredged bottom mud, domestic sewage sludge, and fly ash waste. Starting from the raw material composition, the influence of raw materials on the phosphorus adsorption amount and porosity is studied more precisely, and a ceramsite adsorbent with excellent performance is obtained.

[0025] 2. The present disclosure uses dredged bottom mud, domestic sewage sludge, and fly ash as raw materials and obtains a lightweight ceramsite with both good phosphorus removal performance and high porosity through a suitable process. Description of the Drawings

[0026] Figure 1 SEM images of the ceramsite obtained in Example 17 before and after adsorption;

[0027] Figure 2 FTIR spectra of the ceramsite obtained in Example 17 before and after adsorption;

[0028] Figure 3 XRD patterns of the ceramsite obtained in Example 17 before and after adsorption;

[0029] Figure 4 Shows the phosphorus adsorption amount and phosphorus removal rate of the ceramsite under different ceramsite dosage conditions in Application Example 1;

[0030] Figure 5 It shows the adsorption kinetic curves of ceramsite in Application Example 2 for treating simulated phosphorus wastewater with different concentrations;

[0031] Figure 6 It shows the influence of adsorption time on the phosphorus removal effect of ceramsite in Application Example 2;

[0032] Figure 7a It is a schematic diagram of six groups of anti-disturbance simulation experiments of ceramsite and experimental photos of one of the groups in Application Example 3;

[0033] Figure 7b It is a schematic diagram of the wind disturbance process under three different wind conditions of weak wind, medium wind, and strong wind during the entire experimental process in Application Example 3;

[0034] Figure 8 It shows the change of suspended solids in water under three different wind conditions in Application Example 3;

[0035] Figure 9 It shows the change of P concentration in water under three different wind conditions in Application Example 3;

[0036] Figure 10 It shows the comparison of sediment erosion depth with and without ceramsite coverage under three different wind conditions in Application Example 3. Detailed implementation manners

[0037] The following examples further illustrate the content of the present invention, but should not be construed as a limitation to the present invention. Without departing from the spirit and essence of the present invention, the modifications or substitutions made to the methods, steps or conditions of the present invention belong to the scope of the present invention.

[0038] In the following, the technical solutions of the present disclosure will be described in conjunction with exemplary embodiments.

[0039] The experimental methods used in the following examples are all conventional methods unless otherwise specified.

[0040] The materials, reagents, etc. used in the following examples can be obtained from commercial channels unless otherwise specified.

[0041] The dredged sediment, domestic sewage sludge, and fly ash used in the following examples are dredged sediment, domestic sewage sludge, and fly ash that have been dried and ground through a 100-mesh sieve. At the same time, the content of components such as SiO2 and Al2O3 in the three raw materials was measured by XRF as shown in Table 1 below, where LOI is the loss on ignition.

[0042] Table 1 Content of components such as SiO2 and Al2O3 in dredged sediment, domestic sewage sludge, and fly ash (wt%)

[0043] raw material <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[Fe2O3]]> CaO MgO <![CDATA[Na2O]]> <![CDATA[K2O]]> LOI dredged sediment 55.2％ 17.7％ 6.59％ 12.6％ 1.96％ 0.457％ 3.04％ 2.42％ domestic sludge 36.6％ 12.3％ 19.5％ 5.18％ 2.18％ 0.671％ 2.98％ 18.91％ fly ash 51.2％ 34.2％ 3.63％ 3.99％ 0.998％ 0.438％ 1.32％ 1.29％

[0044] Examples 1-16

[0045] The preparation method of ceramsite is as follows:

[0046] Mix the three raw materials completely according to the following 16 different ratio formulas (weight percentages, see Table 2 below), add water and stir to granulate, obtain green ceramsite and dry it in an oven, and the granule size is 5 mm;

[0047] Put the dried green ceramsite into a crucible, preheat it in a muffle furnace at 400 °C for 15 min, then increase the heating temperature at a heating rate of 10 °C / min after preheating, and then sinter it at 1100 °C for 8 min. Take out the finished ceramsite after the temperature drops, and a total of 16 kinds of ceramsite are obtained.

[0048] An adsorption test is carried out with artificial simulated sewage. 50 ml of artificial simulated sewage, that is, phosphorus-containing wastewater (phosphorus concentration 15 mg / L), is added to the ceramsite prepared in each example, and it is oscillated in a constant temperature oscillator at 25 °C and a rotation speed of 120 r / min for 24 h. The determination method of phosphorus refers to "GB / T 11893-1989 Water Quality - Determination of Total Phosphorus - Ammonium Molybdate Spectrophotometry".

[0049] The porosity of 16 groups of ceramsite is calculated by y2=(m1 - m) / (m1 - m2)×100%, where m is the mass of the ceramsite, m1 is the mass of the ceramsite after soaking in boiling water for 2 h, and m2 is the mass of the ceramsite when weighed in water after soaking in boiling water for 2 h.

[0050] The phosphorus adsorption amount and porosity of the ceramsite prepared in each example measured are shown in Table 2 below.

[0051] Table 2 Dosages (weight percentages) of the three-component raw materials in Examples 1-16 and the properties of the obtained ceramsite

[0052]

[0053]

[0054] Example 17

[0055] The preparation method of the ceramsite in this example is the same as that in Example 1, the difference is only that: the raw material ratio is 61.41 wt% of dredged bottom mud, 14.39 wt% of domestic sewage sludge and 24.20 wt% of fly ash.

[0056] Tested by the same method as in Example 1, the phosphorus adsorption amount of the ceramsite prepared in this example is 0.816 mg / g, and the porosity is 42.75%.

[0057] The scanning electron microscope (SEM) photos of the ceramsite prepared in this example before and after adsorption are shown in Figure 1, As can be seen from the figure, obvious crystal formation occurred after adsorption, and the surface became smoother, proving the occurrence of adsorption.

[0058] The FTIR diagrams of the ceramsite prepared in this example before and after adsorption are shown in Figure 2 , As can be seen from the figure, the absorption peaks at 3434 cm -1 and 1633 cm -1 are the stretching vibration and bending vibration peaks of hydroxyl groups (-OH). Calcium phosphate precipitates such as hydroxyapatite contain O-H groups. Calcium oxide (CaO) may react with phosphate radicals in aqueous solution to form calcium phosphate precipitates (such as hydroxyapatite, Ca5(OH)(PO4)3), usually having absorption peaks near 1633 cm -1 and 3420 cm -1 . This may be the reason for the enhanced absorption at 1633 cm -1 and 3420 cm -1 . At the same time, the characteristic peak at 791 cm -1 is significantly enhanced after phosphorus adsorption. This is the stretching vibration peak of P-OH, indicating that the adsorbed phosphorus may contain part of HPO4 - and H2PO4 2- .

[0059] The XRD diagrams of the ceramsite prepared in this example before and after adsorption are shown in Figure 3 , As can be seen from the figure, the characteristic peaks at 20.74°, 22.29°, 24.37°, and 26.41° correspond to the (100), (011), (003), and (012) crystal planes of AlPO4 respectively, indicating that during the phosphorus adsorption process of the ceramsite, crystalline AlPO4 was also generated. The characteristic peaks at 20.34°, 21.84°, 23.70°, and 25.82° correspond to the (100), (101), (003), and (012) crystal planes of FePO4 respectively, indicating that during the adsorption process of the ceramsite, Fe2O3 loaded in the ceramsite may dissolve due to water or solvent, and Fe 3+ is generated on the surface. These Fe 3+ may react with phosphate radicals to produce FePO4. A new characteristic peak appears at 27.98°. This characteristic peak is the new characteristic peak of Ca5(OH)(PO4)3. The characteristic peaks of Ca5(OH)(PO4)3 exist before and after adsorption, and the diffraction peak intensity of Ca5(OH)(PO4)3 becomes larger after adsorption.

[0060] Application Example 1

[0061] The ceramsite prepared in Example 17 was subjected to a phosphorus removal application test. The specific steps are as follows: 0.5g, 1g, 1.5g, 2g, 2.5g, 3g, 3.5g, and 4g of ceramsite were weighed respectively and loaded into corresponding 100mL centrifuge tubes. 50mL of a simulated phosphorus wastewater solution with a phosphorus concentration of 15mg / L was added to each centrifuge tube. After the bottle cap was tightly plugged, it was placed in a water bath constant temperature shaker, set at 25°C and 120r / min, and shaken for 24h. After the shaking was completed, a certain amount was taken for testing. The results are shown in Figure 4 .

[0062] from Figure 4 It can be seen that when the dosage is small, the ceramsite can provide fewer adsorption sites, and after the adsorption is saturated, it can no longer continue to adsorb the target phosphorus pollutants in the water. At this time, only a small amount of phosphorus is adsorbed and captured by the ceramsite, and the removal rate is low; increasing the dosage, the adsorption sites available for phosphorus pollutants in the ceramsite increase, and the phosphorus removal rate gradually increases; continuing to add ceramsite, the adsorption sites provided by the ceramsite are sufficient, but the amount of phosphorus around the ceramsite is small. When the phosphorus in the water is completely adsorbed, there is no excess phosphorus in the water for the ceramsite to adsorb and capture, and the phosphorus removal rate no longer increases; therefore, increasing the dosage indefinitely will not only not increase the phosphorus removal efficiency of the ceramsite, but will cause a waste of adsorption materials. For the treatment of 15mg / L P high-concentration wastewater, after adding 3g, the phosphorus adsorption amount gradually stabilizes, the removal rate is very high and the increase is not large, so 3g is the optimal dosage, and the optimal dosage of ceramsite is 60g / L (wastewater) after conversion.

[0063] Application Example 2

[0064] The ceramsite prepared in Example 17 was subjected to a phosphorus removal application test. The specific steps are as follows: 3 g of ceramsite was weighed and loaded into 13 round-bottom centrifuge tubes, 50 mL of simulated phosphorus wastewater solution was added to each of the 12 centrifuge tubes, the concentrations were set to 5 mg / L, 20 mg / L, and 50 mg / L, respectively, the oscillation conditions were set to 25°C and 120 r / min, and the corresponding time-marked solutions were taken at 10, 20, 30, 60, 90, 120, 180, 240, 300, 360, 480, and 960 min for testing, and the results are shown in FIG. Figure 5 and Figure 6 .

[0065] from Figure 5 It can be seen that the actual equilibrium adsorption capacity under the pseudo-first-order kinetic model is 0.083 mg / g, 0.295 mg / g, and 0.687 mg / g, and the actual equilibrium adsorption capacity under the pseudo-second-order kinetic model is 0.087 mg / g, 0.296 mg / g, and 0.750 mg / g. Figure 6 The effect of different adsorption time on phosphorus removal by ceramsite is shown. It can be seen that the results obtained by the pseudo-second-order kinetic model are closer to reality, indicating the existence of a chemical adsorption process, which confirms Figure 2 andFigure 3 Occurrence of the resulting chemical reaction; after 180 min, the adsorption approaches equilibrium. Therefore, the adsorption time should be set to more than 180 min, preferably 180 - 360 min.

[0066] Application Example 3 Simulation Experiment (Experiment for Phosphorus Removal and Riverbed Stability Verification)

[0067] The experimental method is as follows:

[0068] In six cylindrical columns, a stirring experiment was carried out by a stirrer. Six groups of simulation experiments were carried out under three conditions of weak wind, medium wind, and strong wind with and without ceramsite coverage. Specifically, in 10 L of simulated sewage, 600 g of ceramsite was added, with a dosage of 60 g / L. As Figure 7a shown, the left side is a schematic diagram of the six cylindrical columns, and the right side also shows a photo of one of the cylindrical columns. The entire experiment lasted for 13 hours, and samples were taken at eight sampling ports at six time intervals (i.e., at 1 h, 3 h, 5 h, 7 h, 10 h, and 13 h of the experiment), and the suspended solids (SS) and soluble reactive phosphorus (SRP) were measured.

[0069] The simulated sewage used in this experiment has the following indicators shown in Table 3 below. Here, DO: dissolved oxygen, EC: conductivity, TP: total phosphorus, SRP: soluble phosphorus in the overlying water, DTP: dissolved total phosphorus, PP: particulate phosphorus. The ceramsite used in this experiment was the ceramsite prepared in Example 17.

[0070] Table 3 Indicators of Simulated Sewage in Application Example 3

[0071] Water temperature (°C) pH <![CDATA[SS (g / m 2 )]]> DO (mg / L) EC (us / cm) 22.1 8.08 12.2 4.59 1286.27 TP (mg / L) SRP (mg / L) DTP (mg / L) PP (mg / L) / 0.3753 0.2291 0.2482 0.1271 /

[0072] In this experiment, the corresponding weak wind, medium wind, and strong wind of the rotation speed were obtained through the fitted formula of rotation speed and wind speed. The wind force classification comes from the definition of wind force classification. Specifically, the wind speeds of weak wind, medium wind, and strong wind are in the following ranges: 0.3 - 1.5 m / s, 3.4 - 5.4 m / s, 10.8 - 13.8 m / s. Then, 1.5 m / s, 5.4 m / s, and 10.8 m / s were taken respectively within the above value ranges. Then, through the conversion formula between frequency and wind speed v = -7.001 + 4.3091n, R 2 = 0.9160, where v is the wind speed (m / s) and n is the disturbance rotation speed (Hz). The frequency of the stirrer was converted to simulate the wind speed disturbance. The weak wind was 1.98 hz, the medium wind was 172 hz, and the strong wind was 247 hz. To be closer to reality, the process of wind force disturbance was divided into a disturbance stage (the first 7 hours of the experiment) and a sedimentation process (the last 6 hours of the experiment), and the disturbance stage included pre-disturbance and actual disturbance. See Figure 7bFor example, in the experiment under a weak wind of 1.5 m / s, the disturbance did not start from 0 and did not immediately reach 1.5 m / s. Instead, it was first disturbed at 0.75 m / s for 2 h, then increased to 1.5 m / s, continuously disturbed for 3 h, then decreased to 0.75 m / s and continuously disturbed for 2 h, and finally the disturbance stopped until the 13th h. In the experiment under a medium wind of 5.4 m / s, it was first disturbed at 2.7 m / s for 2 h, then increased to 5.4 m / s, continuously disturbed for 3 h, then decreased to 2.7 m / s and continuously disturbed for 2 h, and finally the disturbance stopped until the 13th h. In the experiment under a strong wind of 10.8 m / s, it was first disturbed at 5.4 m / s for 2 h, then increased to 10.8 m / s, continuously disturbed for 3 h, then decreased to 5.4 m / s and continuously disturbed for 2 h, and finally the disturbance stopped until the 13th h.

[0073] Figure 8 shows the changes of suspended solids in water under different wind conditions in this experiment; it can be seen that, compared with the non-covered case, the effect of reducing suspended solids in water is obvious after covering with ceramsite under weak and medium winds, and the fluctuations during the experiment are not as large as those under other wind conditions, but the inhibition under strong wind is limited, that is, compared with the case without covering with ceramsite under strong wind, the suspended solids decrease in the case of covering with ceramsite, but the effect is relatively not obvious.

[0074] Figure 9 shows the changes of P concentration in water under different wind conditions in this experiment; it can be seen that the adsorption effect of P in water after covering with ceramsite is good compared with the non-covered case under each wind condition.

[0075] Figure 10 shows the comparison of sediment erosion depth under different wind conditions with or without ceramsite covering in this experiment; it can be seen that after covering with ceramsite, the sediment erosion depth is significantly reduced. The sediment erosion depth represents the degree to which the sediment is suspended and eroded under disturbance, and the reduction of the erosion depth indicates that the stability of the riverbed increases under the ceramsite covering. Therefore, the ceramsite prepared in this application can enhance the stability of the riverbed.

[0076] Finally, it should also be noted that in this disclosure, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent in such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0077] Although the present disclosure has been disclosed above through the description of specific embodiments of the present disclosure, it should be understood that those skilled in the art can design various modifications, improvements or equivalents to the present disclosure within the spirit and scope of the appended claims. These modifications, improvements or equivalents should also be considered to be included within the scope claimed by the present disclosure.

Claims

1. A method for making phosphorus-adsorbing bottom mud ceramsite for reuse in river channels, characterized in that, Including: Mix a certain proportion of dredged sediment, domestic sewage sludge, and fly ash evenly, add water and stir to granulate, obtain green ceramsite and perform drying treatment; The addition proportion of the dredged sediment is 24.3wt% - 96.3wt%, the addition proportion of the domestic sewage sludge is 0wt% - 32.6wt%, and the addition proportion of the fly ash is 3.71wt% - 52wt%; Perform sintering treatment on the dried green ceramsite, and obtain the ceramsite after cooling.

2. The manufacturing method of the phosphorus-adsorbing sediment ceramsite according to claim 1, characterized in that The particle size of the green ceramsite is 3mm - 8mm; preferably 5mm ± 0.5mm.

3. The method for manufacturing phosphorus-adsorbing sediment ceramsite according to claim 1 or 2, characterized in that, The addition proportion of the dredged sediment is 54.91wt% - 96.30wt%.

4. The method for manufacturing phosphorus-adsorbing sediment ceramsite according to any one of claims 1 to 3, characterized in that, The addition proportion of the domestic sewage sludge is 13.39wt% - 32.69wt%, and the addition proportion of the fly ash is 4.39wt% - 51.93wt%.

5. The manufacturing method of the phosphorus-adsorbing sediment ceramsite according to claim 1 or 2, characterized in that, The addition proportion of the dredged sediment is 48 - 82%, the addition proportion of the domestic sewage sludge is 8 - 18%, and the addition proportion of the fly ash is 3 - 40%.

6. The manufacturing method of the phosphorus-adsorbing sediment ceramsite according to claim 5, characterized in that, The addition proportion of the dredged sediment is 60 - 62%, the addition proportion of the domestic sewage sludge is 13 - 15%, and the addition proportion of the fly ash is 24 - 26%.

7. The manufacturing method of the phosphorus-adsorbing sediment ceramsite according to claim 6, characterized in that, The addition proportion of the dredged sediment is 61.41%, the addition proportion of the domestic sewage sludge is 14.39%, and the addition proportion of the fly ash is 24.20%.

8. The manufacturing method of the phosphorus-adsorbing sediment ceramsite according to any one of claims 1-7, characterized in that, The sintering treatment includes: preheating at 380 - 420°C for 12 - 18 min first, then increasing the heating temperature at a heating rate of 8 - 12°C / min, and then sintering at 1050 - 1150°C for 6 - 10 min; Preferably, the sintering treatment includes: preheating at 400°C for 15 min first, then increasing the heating temperature at a heating rate of 10°C / min, and then sintering at 1100°C for 8 min.

9. A phosphorus-adsorbing sediment ceramsite for river reuse, which is made by the manufacturing method described in any one of claims 1 - 8. Preferably, the phosphorus adsorption capacity of the ceramsite is 0.60 - 0.82mg / g, and the porosity is 39% - 52%.

10. Application of the phosphorus-adsorbing sediment ceramsite according to claim 9 in any one of the following (1) - (2): (1) Application in wastewater phosphorus removal; (2) Application in river water body phosphorus removal.

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