Degradable microfiller as well as preparation method and application thereof

Abstract

The invention discloses a degradable microfiller as well as a preparation method and application thereof. The preparation method comprises the following steps: 1) preparation of inner core balls: mixing rice hull ash, clay and water supply sludge with the water content of 50-65 wt%, and performing high-temperature reaction to obtain the inner core balls; 2) fixing a stripping layer: mixing rice hull ash and alum to form a first mixture, adding the first mixture into the inner core ball, and then performing high-temperature treatment to obtain a semi-finished product filler ball; and 3) fixation of the adding layer: mixing water supply sludge with the water content of below 30wt% and clay to form a second mixture, contacting the semi-finished product filler ball with the second mixture, and performing firing treatment to obtain the irregular spherical microfiller. According to the technical scheme, waste is used for treating waste, the water supply sludge is provided, and the dosage of suspended filler in the sewage treatment process and the dosage of a dewatering agent in the subsequent sludge dewatering process are reduced. And economic and social benefits are obtained while the problem of environmental pollution is solved.

Description

Technical Field

[0001] The invention belongs to the field of environmental management, and in particular relates to a degradable micro-filler prepared by utilizing water supply sludge, and a preparation method and application thereof. Background Art

[0002] Due to the industry's long-term emphasis on water and neglect of sludge, sludge disposal has become an important bottleneck restricting the healthy development of sewage treatment plants.

[0003] The water content of municipal sludge is extremely high, which can reach 99% or even higher. It also contains heavy metals, organic matter, plant nutrients such as nitrogen and phosphorus, and toxic and harmful organic matter. The sludge flocs are in a colloidal state, which is easy to deteriorate and even cause epidemics, and it is very easy to cause secondary pollution. Mechanical dehydration is the most common way to dehydrate sludge. Common dehydrators include centrifuges, filter presses, vacuum filters, etc. It mainly relies on the pressure difference on both sides of the filter medium as a driving force to force the sludge and water to separate. However, the water content of sludge cannot be effectively reduced directly through mechanical dehydration. After concentration and mechanical dehydration, the water content of the sludge in the sewage treatment plant is still as high as about 85%, and the problem of high cost when drying sludge is not solved. The country advocates reducing the water content of sludge to below 60%. In the prior art, technicians in this field usually further reduce the water content of sludge by adding a large amount of conditioning agents.

[0004] The conventional water treatment process of urban water plants includes coagulation, flocculation, sedimentation, filtration and disinfection. A large amount of sludge, namely water supply sludge, will be produced during the coagulation process. Water supply sludge not only contains a large amount of pollutants from natural water sources, such as suspended solids, colloids, algae and coloring organic matter, but also contains a large amount of sewage treatment agents. Compounds such as CaCO3, SiO2, Fe2O3, Al2O3 are the main components of water supply sludge. The main components of water supply sludge are exactly the main components of the conditioner added for sludge dehydration. Therefore, water supply sludge is often prepared as sludge dehydration agent on the market.

[0005] How to utilize the existing resource of water supply sludge, how to solve the problem of municipal sludge dehydration, how to reduce the use of fillers in sewage treatment, how to reduce the use of dehydrating agents in municipal sludge dehydration, and how to comprehensively consider, reduce and complement the above issues are bottleneck issues that need to be solved and broken through. Summary of the invention

[0006] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a technical solution for treating waste with waste: to provide a degradable micro-filler prepared by using water supply sludge, and a preparation method and application thereof. The degradable micro-filler prepared by using water supply sludge can not only solve the dehydration problem of municipal sludge, but also effectively reduce the amount of suspended filler used in the municipal sewage treatment process, as well as the amount of dehydrating agent used in the subsequent dehydration of municipal sludge. In order to achieve the above purpose and other related purposes, the present invention is obtained by the following technical solution.

[0007] The first aspect of the present invention provides a method for preparing a degradable micro-filler using water supply sludge, comprising the following steps:

[0008] 1) Preparation of the inner core ball: rice husk ash, clay and water supply sludge with a moisture content of 50wt% to 65wt% are mixed and subjected to high temperature reaction to obtain the inner core ball;

[0009] 2) Fixing the peeling layer: mixing rice husk ash and alum to form a first mixture, the first mixture is in contact with the core ball, and then subjected to high temperature treatment to obtain a semi-finished filler ball;

[0010] 3) Fixing of the cross-layer: water supply sludge with a moisture content of less than 30 wt% and clay are mixed to form a second mixture, the semi-finished filler balls are in contact with the second mixture, and then fired to obtain irregular spherical micro-fillers.

[0011] Preferably, in step 1), the mass ratio of rice husk ash, clay and water supply sludge with a moisture content of 50wt% to 65wt% is 1 to (3:1): (6 to 10).

[0012] Preferably, in step 1), the feed sludge with a moisture content of 50 wt% to 65 wt% is obtained by passing through a sludge dewatering machine and then drying in the shade.

[0013] Preferably, in step 1), the high temperature reaction is carried out under vacuum conditions.

[0014] Preferably, in step 1), the temperature of the high temperature reaction is 120-160° C., and the reaction time is 4-6 hours.

[0015] Preferably, in step 1), after the high temperature reaction is completed, the step further includes screening using a 60-80 mesh sieve.

[0016] Preferably, in step 1), after the high temperature reaction is completed, cooling is further included. More preferably, the cooling is vacuum cooling, and the time of passing through the vacuum environment is 3 to 7 seconds.

[0017] Preferably, in step 2), the mass ratio of rice husk ash to alum is 2:(1-4).

[0018] Preferably, in step 2), the volume ratio of the first mixture to the inner core ball is 1:(4-8).

[0019] Preferably, in step 2), the contact time between the first mixture and the inner core ball is 5 to 10 minutes. When adding the first mixture, the balls are prevented from sticking to each other.

[0020] Preferably, in step 2), the temperature of the high temperature treatment is 100-120°C.

[0021] Preferably, in step 3), the feed sludge with a moisture content of less than 30 wt% is obtained by post-drying or drying with a sludge dewatering machine.

[0022] Preferably, in step 3), the mass ratio of the water supply sludge with a moisture content of less than 30wt% and the clay is (4-7):1.

[0023] Preferably, in step 3), in the semi-finished filler balls, the mass ratio of the semi-finished filler balls to the second mixture is (7-9):1.

[0024] Preferably, in step 3), the firing temperature is 900-1500°C and the firing time is 0.5-1h. During the firing process, the water sludge, rice husk ash and alum are dissolved to promote the micro-filler to form a porous irregular shape, which is conducive to the enrichment of activated sludge.

[0025] The addition of clay is to enhance the shaping and prevent the filler from cracking during the firing process. At the same time, the amount of clay added is small, in order to stabilize the filler in a short period of time, that is, to maintain the filler stable within 20-30 days.

[0026] The second aspect of the present invention provides a degradable microfiller prepared by the preparation method as described above.

[0027] Preferably, the degradable micro-filler is an irregular sphere, and the diameter of the sphere is 3 to 5 cm.

[0028] A third aspect of the present invention provides a use of the above-mentioned degradable microfiller in treating sewage in an activated sludge process and its derived aerobic process.

[0029] Preferably, when the activated sludge process is used to treat sewage, the degradable micro-filler is used as a growth carrier of activated sludge to purify sewage, and is equivalent to a chemical agent to promote sludge dehydration.

[0030] Preferably, the aerobic tanks suitable for the degradable micro-fillers include one or more of A2 / O or A / O system aerobic tanks.

[0031] Preferably, the hydraulic retention time (HRT) of the aerobic pool is 4 to 6 hours, and the oxygenation power efficiency EP is 6 to 8 kgO2 / (kW.h).

[0032] The fourth aspect of the present invention provides a sewage treatment method using the degradable micro-filler as described above. When the activated sludge method is used to treat sewage, when the effective volume of the aerobic tank is 100%, the amount of activated sludge added is 40% to 55% of the effective volume, and the amount of degradable micro-filler added is 10% to 20% of the effective volume.

[0033] Preferably, when using the activated sludge method to treat sewage, when the effective volume of the aerobic tank is 100%, the amount of activated sludge added is 20% to 40% of the effective volume, the amount of degradable microfiller added is 20% to 30% of the effective volume, and the amount of suspended filler added is 15 to 40% of the effective volume.

[0034] In the present invention, clay is added to prevent filler cracking during the firing process, which causes the microfiller to break prematurely during application, thereby affecting the adsorption effect of the microfiller on the activated sludge, and at the same time avoids the accumulation of microfillers in the aerobic tank caused by premature breakage of the microfiller, resulting in excessive concentration of activated sludge.

[0035] In the present invention, during sewage treatment before the micro-filler is crushed, rice husk ash can be used as a coagulant auxiliary to help the micro-filler to set its shape. And because rice husk ash can generate sodium silicate solids under corresponding reaction conditions, the sodium silicate solids are unstable for a long time, thus promoting the degradation of the micro-filler. As described above, the present invention provides a degradable micro-filler prepared using water supply sludge, and a preparation method and application thereof. The degradable micro-filler is prepared from water supply sludge, and while solving the problem of municipal sludge dehydration, it can also effectively reduce the amount of suspended filler used in the sewage treatment process, as well as the amount of dehydrating agent used in the subsequent municipal sludge dehydration, playing a role in turning waste into treasure and treating waste with waste. While solving the problem of environmental pollution, good economic and social benefits have been achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Shown is a schematic diagram of the structure of the degradable microfiller of the present invention.

[0037] The following are the descriptions of the reference numerals:

[0038] 100 interleaving layers

[0039] 200 peeling layer

[0040] 300 core balls DETAILED DESCRIPTION

[0041] The following is an explanation of the embodiments of the present invention by specific examples to verify the practical feasibility of the method of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0042] It should be noted that the process equipment or devices not specifically specified in the following examples are all conventional equipment or devices in the art. In addition, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below, and one or more method steps mentioned in the present invention do not exclude the presence of other method steps before and after the combination step or the insertion of other method steps between these explicitly mentioned steps, unless otherwise specified. It should also be understood that the terms used in the examples of the present invention are intended to describe specific embodiments, not to limit the scope of protection of the present invention. The test methods for which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under the conditions recommended by the manufacturers.

[0043] The following examples use a specific method for preparing a degradable micro-filler using water supply sludge, comprising the following steps:

[0044] 1) Preparation of the core ball:

[0045] 1-1) squeezing the water supply sludge with a sludge dehydrator and then drying it in the shade until the water content is 50wt% to 65wt%, thereby obtaining water supply sludge with a water content of 50wt% to 65wt%;

[0046] 1-2) fully mixing rice husk ash, clay and water supply sludge with a moisture content of 50wt% to 65wt%, wherein the mass ratio of the rice husk ash, clay and water supply sludge with a moisture content of 50wt% to 65wt% is (1 to 3):1:(6 to 10);

[0047] 1-3) Under vacuum conditions, a high temperature reaction is carried out at a temperature of 120 to 160° C. for a reaction time of 4 to 6 hours;

[0048] 1-4) After high temperature reaction, it passes through a 60-80 mesh screen and falls into a vacuum cylinder for 3-7 seconds, and finally falls into ice water in the vacuum cylinder and is rapidly cooled to form a core ball.

[0049] 2) Fixing of peeling layer:

[0050] 2-1) mixing rice husk ash and alum to form a first mixture, wherein the mass ratio of the rice husk ash to the alum is 2:(1-4);

[0051] 2-2) contacting the first mixture obtained in 2-1) with the inner core ball, wherein the volume ratio of the first mixture to the inner core ball is 1:(4-8), and the contact time between the first mixture and the inner core ball is 5-10 minutes;

[0052] 2-3) performing high temperature treatment at a temperature of 100 to 120° C. to obtain semi-finished filler balls.

[0053] 3) Fixing of the cross-layer:

[0054] 3-1) The water supply sludge is squeezed by a sludge dehydrator and then dried or dried until the water content is below 30wt% to obtain water supply sludge with a water content of below 30wt%;

[0055] 3-2) mixing water supply sludge with a moisture content of less than 30 wt% and clay to form a second mixture, wherein the mass ratio of the water supply sludge with a moisture content of less than 30 wt% and the clay is (4-7):1;

[0056] 3-3) The semi-finished filler balls are contacted with the second mixture in 3-2), the mass ratio of the semi-finished filler balls to the second mixture is (7-9):1, and then fired at a temperature of 900-1500°C for 0.5-1h to obtain irregular spherical microfillers.

[0057] Example 1

[0058] In this embodiment, a method for preparing a degradable micro-filler using water supply sludge is provided, comprising the following steps:

[0059] 1) Preparation of the core ball:

[0060] 1-1) squeezing the water supply sludge with a sludge dehydrator and then drying it in the shade until the water content is 50wt%, thereby obtaining water supply sludge with a water content of 50wt%;

[0061] 1-2) rice husk ash, clay and water sludge with a moisture content of 50wt% are fully mixed, the mass ratio of the rice husk ash, clay and water sludge with a moisture content of 50wt% is 2:1:7, and the masses of the rice husk ash, clay and water sludge with a moisture content of 50wt% are 60g, 30g and 210g respectively;

[0062] 1-3) Under vacuum conditions, a high temperature reaction is carried out at 140°C for 4 hours;

[0063] 1-4) After high temperature reaction, it passes through a 60-mesh screen and falls into a vacuum cylinder for 5 seconds, and finally falls into ice water in the vacuum cylinder and is quickly cooled to form a core ball.

[0064] 2) Fixing of peeling layer:

[0065] 2-1) mixing rice husk ash and alum to form a first mixture, wherein the mass ratio of the rice husk ash to the alum is 1:1;

[0066] 2-2) contacting the first mixture obtained in 2-1) with the inner core ball, wherein the volume ratio of the first mixture to the inner core ball is 1:5, and the contact time between the two is 5 minutes;

[0067] 2-3) performing high temperature treatment at a temperature of 100° C. to obtain semi-finished filler balls.

[0068] 3) Fixing of the cross-layer:

[0069] 3-1) The water supply sludge is squeezed by a sludge dehydrator and then dried or dried to a moisture content of 30 wt %, thereby obtaining water supply sludge with a moisture content of 30%;

[0070] 3-2) mixing water supply sludge with a moisture content of 30 wt% and clay to form a second mixture, wherein the mass ratio of the water supply sludge with a moisture content of 30 wt% to the clay is 5:1;

[0071] 3-3) The semi-finished filler balls are contacted with the second mixture in 3-2), the mass ratio of the semi-finished filler balls to the second mixture is 7:1, and then fired at a temperature of 1200°C for 0.5h to obtain irregular spherical micro-fillers. The average diameter of the spheres obtained at this time is 5cm, and the total weight of the spheres is about 150g.

[0072] Example 2

[0073] In this embodiment, a method for preparing a degradable micro-filler using water supply sludge is provided, comprising the following steps:

[0074] 1) Preparation of the core ball:

[0075] 1-1) squeezing the water supply sludge with a sludge dehydrator and then drying it in the shade until the water content is 65wt%, thereby obtaining water supply sludge with a water content of 65wt%;

[0076] 1-2) rice husk ash, clay and water sludge with a moisture content of 65wt% are fully mixed, wherein the mass ratio of the rice husk ash, clay and water sludge with a moisture content of 65wt% is 2:1:8, and the masses of the rice husk ash, clay and water sludge with a moisture content of 65wt% are 68g, 34g and 272g respectively;

[0077] 1-3) Under vacuum conditions, a high temperature reaction is carried out at a temperature of 130° C. and a reaction time of 5 h;

[0078] 1-4) After high temperature reaction, it passes through a 60-mesh screen and falls into a vacuum cylinder for 5 seconds, and finally falls into ice water in the vacuum cylinder and is quickly cooled to form a core ball.

[0079] 2) Fixing of peeling layer:

[0080] 2-1) mixing rice husk ash and alum to form a first mixture, wherein the mass ratio of the rice husk ash to the alum is 1:1;

[0081] 2-2) contacting the first mixture obtained in 2-1) with the inner core ball, wherein the volume ratio of the first mixture to the inner core ball is 1:5, and the contact time between the two is 5 minutes;

[0082] 2-3) performing high temperature treatment at a temperature of 100° C. to obtain semi-finished filler balls.

[0083] 3) Fixing of the cross-layer:

[0084] 3-1) The water supply sludge is squeezed by a sludge dehydrator and then dried or dried to a moisture content of 30 wt %, thereby obtaining water supply sludge with a moisture content of 30 wt %;

[0085] 3-2) mixing water supply sludge with a moisture content of 30 wt% and clay to form a second mixture, wherein the mass ratio of the water supply sludge with a moisture content of 30 wt% to the clay is 5:1;

[0086] 3-3) The semi-finished filler balls are contacted with the second mixture in 3-2), the mass ratio of the semi-finished filler balls to the second mixture is 7:1, and then fired at a temperature of 1200°C for 0.5h to obtain irregular spherical micro-fillers. The average diameter of the spheres obtained at this time is 5cm, and the total weight of the spheres is about 150g.

[0087] Example 3

[0088] In this embodiment, a method for preparing a degradable micro-filler using water supply sludge is provided, comprising the following steps:

[0089] In this embodiment, a method for preparing a degradable micro-filler using water supply sludge is provided, comprising the following steps:

[0090] 1) Preparation of the core ball:

[0091] 1-1) squeezing the water supply sludge with a sludge dehydrator and then drying it in the shade until the water content is 50wt%, thereby obtaining water supply sludge with a water content of 50wt%;

[0092] 1-2) rice husk ash, clay and water sludge with a moisture content of 50wt% are fully mixed, the mass ratio of the rice husk ash, clay and water sludge with a moisture content of 50wt% is 2:1:7, and the masses of the rice husk ash, clay and water sludge with a moisture content of 50wt% are 50g, 25g and 175g respectively;

[0093] 1-3) Under vacuum conditions, a high temperature reaction is carried out at a temperature of 130° C. and a reaction time of 5 h;

[0094] 1-4) After high temperature reaction, it passes through a 60-mesh screen and falls into a vacuum cylinder for 5 seconds, and finally falls into ice water in the vacuum cylinder and is quickly cooled to form a core ball.

[0095] 2) Fixing of peeling layer:

[0096] 2-1) mixing rice husk ash and alum to form a first mixture, wherein the mass ratio of the rice husk ash to the alum is 1:1;

[0097] 2-2) contacting the first mixture obtained in 2-1) with the inner core ball, wherein the volume ratio of the first mixture to the inner core ball is 1:5, and the contact time between the two is 5 minutes;

[0098] 2-3) performing high temperature treatment at a temperature of 100° C. to obtain semi-finished filler balls.

[0099] 3) Fixing of the cross-layer:

[0100] 3-1) The water supply sludge is squeezed by a sludge dehydrator and then dried or dried to a moisture content of 25wt%, thereby obtaining water supply sludge with a moisture content of 25wt%;

[0101] 3-2) mixing water supply sludge with a moisture content of 25 wt% and clay to form a second mixture, wherein the mass ratio of the water supply sludge with a moisture content of 25% to the clay is 6:1;

[0102] 3-3) The semi-finished filler balls are contacted with the second mixture in 3-2, the mass ratio of the semi-finished filler balls to the second mixture is 8:1, and then fired at a temperature of 1200°C for 0.5h to obtain irregular spherical micro-fillers. The average diameter of the spheres obtained at this time is 4cm, and the total weight of the spheres is about 130g.

[0103] Comparative Example 1

[0104] The difference between this comparative example and Example 1 is that, except for step 1), no rice husk ash is added, the rest is completely the same as Example 1.

[0105] Comparative Example 2

[0106] The difference between this comparative example and Example 1 is that, except for step 1), no clay is added, the rest of the steps are completely the same as those in Example 1.

[0107] Comparative Example 3

[0108] The difference between this comparative example and Example 1 is that, except for step 1), the masses of the rice husk ash, clay and water sludge with a moisture content of 50 wt% are 20 g, 10 g and 80 g respectively; in step 3), the average diameter of the obtained spheres is 2 cm, and the total weight of the spheres is about 60 g, and the rest is exactly the same as Example 1.

[0109] Comparative Example 4

[0110] The difference between this comparative example and Example 1 is that, except for step 1), the masses of the rice husk ash, clay and water sludge with a moisture content of 50 wt% are 75 g, 37.5 g and 262.5 g respectively; in step 3), the average diameter of the obtained spheres is 6 cm and the total weight is about 200 g, and the rest is exactly the same as Example 1.

[0111] Comparative Example 5

[0112] The difference between this comparative example and Example 1 is that, except for step 1), the masses of the rice husk ash, clay and water sludge with a moisture content of 50 wt% are 87.6 g, 43.8 g and 306.6 g respectively; in step 3), the average diameter of the obtained spheres is 7 cm and the total weight is about 225 g, and the rest is exactly the same as Example 1.

[0113] Comparative Example 6

[0114] The difference between this comparative example and Example 1 is that, except for step 1), the masses of the rice husk ash, clay and water sludge with a moisture content of 50wt% are 100g, 50g and 350g respectively; in step 3), the average diameter of the obtained spheres is 8cm and the total weight is about 260g, and the rest is exactly the same as Example 1.

[0115] Comparative Example 7

[0116] The difference between this comparative example and Example 1 is that, except for step 1), the masses of the rice husk ash, clay and water sludge with a moisture content of 50 wt% are 112.6 g, 56.3 g and 394.1 g respectively; in step 3), the average diameter of the obtained spheres is 9 cm and the total weight is about 290 g, and the rest is exactly the same as Example 1.

[0117] Comparative Example 8

[0118] The difference between this comparative example and Example 1 is that, except for step 1), the masses of the rice husk ash, clay and water sludge with a moisture content of 50 wt% are 125 g, 62.5 g and 437.5 g respectively; in step 3), the average diameter of the obtained spheres is 10 cm and the total weight is about 345 g, and the rest is exactly the same as Example 1.

[0119] Application Example 1

[0120] The degradable micro-filler prepared in Example 1 was applied to the aerobic pool of the A / O system, wherein the HRT of the aerobic pool was 4 h, and the oxygenation power efficiency EP was 6 kgO2 / (kW.h).

[0121] When the effective volume of the aerobic tank is 100%, the dosage of activated sludge is 20% of the effective volume, the dosage of degradable micro-filler is 20% of the effective volume, and the dosage of suspended filler is 15% of the effective volume.

[0122] In the sewage treatment process, the degradable micro-filler has the same function as the suspended filler, providing attachment growth points for microorganisms in the activated sludge to purify the sewage. In the process of continuous aeration and sludge discharge, the degradable micro-filler gradually disperses and breaks, exposing its inner core. Due to the strong adsorption of phosphorus by water sludge, a large amount of phosphorus in the sewage can be taken away during the sludge discharge process, and the phosphorus removal rate can reach 94%. After the degradable micro-filler is broken, it is mixed with the sludge.

[0123] After sludge discharge, in the process of sludge dewatering:

[0124] First, concentrate: use the sludge dewatering machine to preliminarily dehydrate the sludge, concentrate the water in the sludge and discharge it;

[0125] Re-filtration: The concentrated sludge is directly sent to the filter press to further remove the water in the sludge;

[0126] Re-drying: The filtered sludge is dried using a dryer.

[0127] The test shows that when the degradable filler provided by the present invention is used, the dosage of the suspended filler is only 15% of the effective volume, which greatly reduces the use of the suspended filler in the prior art; in addition, no chemical agents, including flocculants, integrators, etc., need to be added during the sludge dehydration process, which reduces the use of dehydration agents. The moisture content of the dehydrated sludge was tested and it was found that the moisture content of the sludge was reduced from about 99% to 55%, and the sludge volume was reduced to 1 / 3 of the original.

[0128] The fillers prepared in Example 1 and Comparative Examples 1 to 8 were respectively placed in an aerobic tank of an A / O system for application testing. The test results are shown in Table 1.

[0129] Table 1

[0130]

[0131]

[0132] As can be seen from Table 1, the degradable microfiller obtained by the preparation method of the present application (the microfiller prepared in Example 1) has good porosity. This is because during the firing process, water from the water sludge, rice husk ash, alum and other substances in the microfiller are dissolved to promote the microfiller to form a porous irregular shape, which is conducive to the enrichment of activated sludge; after being placed in an aerobic tank, it has good floating performance and the activated sludge has strong adhesion on it; in the process of continuous aeration and sludge discharge, the filler is broken and degraded within 20 to 30 days, and can be used as a chemical agent to help the subsequent dehydration of sludge. Compared with Example 1, the microfiller provided in Comparative Example 1 remains intact for a long time after being placed in an aerobic tank, and there is a phenomenon of incomplete crushing and inability to completely degrade. Therefore, it cannot be used as a chemical agent for the subsequent dehydration of sludge. Compared with Example 1, the microfiller provided in Comparative Example 2 is poorly formed and is broken during the firing process. Compared with Example 1, the microfiller provided in Comparative Example 3 remains intact for a long time after being placed in the aerobic tank, and is not easy to break and degrade, so it cannot be used as a chemical agent for subsequent sludge dewatering. Compared with Example 1, the microfillers provided in Comparative Examples 4 to 8 are larger in volume, break earlier after being placed in the aerobic tank, have poor floating performance, poor activated sludge adhesion, and poor sewage purification ability.

[0133] In summary, the degradable micro-filler prepared by the technical solution provided by the present invention can play the role of suspended filler in the sewage treatment process before crushing, and can effectively reduce a large amount of phosphorus in the sewage, reducing the amount of suspended filler used. In the process of sludge dehydration after crushing, it can also play the role of chemical agent, which is beneficial to sludge dehydration and reduces the amount of chemical agents used in the sludge dehydration process. At the same time, it also finds a suitable way out for the use of water supply sludge, has the effect of turning waste into treasure and treating waste with waste, and can solve environmental pollution problems while achieving good economic and social benefits.

[0134] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for preparing a degradable microfiller using water supply sludge, characterized in that: The preparation method comprises the following steps: 1) Preparation of the inner core ball: rice husk ash, clay and water supply sludge with a moisture content of 50wt% to 65wt% are mixed and subjected to high temperature reaction to obtain the inner core ball; 2) Fixing the peeling layer: mixing rice husk ash and alum to form a first mixture, the first mixture is in contact with the core ball, and then subjected to high temperature treatment to obtain a semi-finished filler ball; 3) Fixing of the cross-layer: water supply sludge with a moisture content of less than 30 wt% and clay are mixed to form a second mixture, the semi-finished filler balls are in contact with the second mixture, and then fired to obtain irregular spherical micro-fillers.

2. The preparation method according to claim 1, characterized in that: In the step 1), the mass ratio of rice husk ash, clay and water supply sludge with a moisture content of 50wt% to 65wt% is (1 to 3): 1: (6～10)； And / or, in step 1), the water supply sludge with a moisture content of 50wt% to 65wt% is obtained by passing through a sludge dewatering machine and then drying in the shade; And / or, in step 1), the high temperature reaction is carried out under vacuum conditions; And / or, the temperature of the high temperature reaction is: 120-160° C., and the reaction time is 4-6 hours; And / or, in step 1), after the high temperature reaction is completed, the step further includes screening using a 60-80 mesh sieve; And / or, in step 1), after the high temperature reaction is completed, cooling is also included, preferably vacuum cooling.

3. The preparation method according to claim 1, characterized in that: In the step 2), the mass ratio of rice husk ash to alum is 2:(1-4); and / or, in step 2), the volume ratio of the first mixture to the inner core ball is 1:(4-8); and / or, in step 2), the contact time between the first mixture and the inner core ball is 5 to 10 minutes; And / or, in step 2), the temperature of the high temperature treatment is 100-120°C.

4. The preparation method according to claim 1, characterized in that: In the step 3), the feed water sludge with a moisture content of less than 30 wt% is dried or dried by a sludge dewatering machine; And / or, in step 3), the mass ratio of the water supply sludge having a moisture content of less than 30 wt% and the clay is (4-7):1; And / or, in step 3), in the semi-finished filler balls, the mass ratio of the semi-finished filler balls to the second mixture is (7-9):1; And / or, in step 3), the temperature of the firing treatment is: 900-1500° C., and the firing time is 0.5-1 h.

5. A degradable microfiller prepared by the preparation method according to any one of claims 1 to 4.

6. The degradable microfiller according to claim 5, characterized in that: The degradable micro-filler is an irregular sphere, and the average diameter of the sphere is 3 to 5 cm.

7. Use of the degradable microfiller as claimed in any one of claims 5 to 6 in treating sewage in an activated sludge process and its derived aerobic process.

8. The use according to claim 7, characterized in that: When the activated sludge method is used to treat sewage, the degradable micro-filler is used as a growth carrier of the activated sludge to purify the sewage, and is equivalent to a chemical agent to promote sludge dehydration.

9. A method for treating sewage using the degradable microfiller according to any one of claims 5 to 6, characterized in that: When using the activated sludge method to treat sewage, when the effective volume of the aerobic tank is 100%, the dosage of activated sludge is 40% to 55% of the effective volume, and the dosage of the degradable micro-filler is 10% to 20% of the effective volume.

10. The processing method according to claim 9, characterized in that: When using the activated sludge method to treat sewage, when the effective volume of the aerobic tank is 100%, the amount of activated sludge added is 20% to 40% of the effective volume, the amount of degradable micro-filler added is 20% to 30% of the effective volume, and the amount of suspended filler added is 15% to 40% of the effective volume.

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