CN112897950B

CN112897950B - Preparation method of microbial carrier by taking sludge as raw material

Info

Publication number: CN112897950B
Application number: CN202110148451.XA
Authority: CN
Inventors: 陈玺; 胡宝伽; 郭沨; 吴磊; 张宗仰; 蔡维国
Original assignee: China Gezhouba Group Ecological Environment Engineering Co ltd
Current assignee: Gezhouba Group Ecological Environmental Protection Co ltd
Priority date: 2021-02-03
Filing date: 2021-02-03
Publication date: 2022-08-16
Anticipated expiration: 2041-02-03
Also published as: CN112897950A

Abstract

The invention discloses a microbial carrier taking sludge as a raw material and a preparation method thereof, wherein the raw material of the microbial carrier comprises dehydrated sludge powder, cement, fly ash, zeolite powder, diatomite and bentonite, and the weight ratio is (0.5-3): 6-10): 2-6): 3-8): 1-3): 2-4; the preparation method of the dewatered sludge powder comprises the steps of firstly taking sludge or sludge to remove impurities, and standing for precipitation; the lower layer of settled sludge is left for dewatering; drying at 95-105 deg.C to constant weight, cooling, grinding, and sieving to obtain dehydrated mud powder crude product; and finally, adding a biological enzyme solution into the crude dehydrated mud powder, mixing and stirring uniformly, and putting into a closed container to blank for 15-24h to obtain the dehydrated mud powder. The method has the advantages that the river silt or sludge is treated by the biological enzyme and then is combined with materials such as cement, fly ash, zeolite powder, diatomite, bentonite (montmorillonite) and the like, so that the microbial proliferation rate of the prepared carrier is obviously improved, and the treatment effect on total nitrogen and nitrate nitrogen in the sewage is improved.

Description

Preparation method of microbial carrier by taking sludge as raw material

Technical Field

The invention belongs to the technical field of sludge treatment, and particularly relates to a microbial carrier taking sludge as a raw material.

Background

With the rapid development of the water environment treatment industry, the amount of activated sludge generated by dredging is continuously increased. Because activated sludge is characterized by high water content, loose structure, high organic content, and toxic and harmful substances (such as microorganisms, heavy metals, and toxic organisms), it has become an important environmental problem and needs to be disposed of in an efficient manner. At present, sludge utilization is one of the important methods for sludge treatment. The dredged sludge has wide sources, is cheap and easy to obtain, can be used as a carbon source material of microorganisms, provides a growth and adhesion space for the microorganisms, and simultaneously performs resource utilization on the sludge, reduces the sludge treatment quantity, and saves environmental resources and social resources.

In the prior art, chinese patent application CN104230301A provides a biocompatible hydrophilic magnetic sludge ceramic sand carrier, which is prepared from raw materials such as sludge (or silt), fly ash, cement, lime, gypsum, and magnetic powder, and serves as a physical attachment point for microorganisms and provides nutrients for the microorganisms, so that the microorganisms can grow more easily.

Chinese granted patent CN105950602A provides a microorganism immobilization method and immobilized flocculation bacteria particles, which comprises mixing polyacrylamide bacteria solution, polyaluminium chloride, cement, and activated carbon (or zeolite, fly ash), drying to obtain immobilized flocculation bacteria particle precursor, and repeatedly soaking and drying to obtain immobilized flocculation bacteria particles.

The Chinese patent CN100383060C provides a microbial composite carrier, which uses humus soil, fly ash, calcium silicate, kaolin, limonite and/or zeolite as injection materials, and then adds starch, calcium alginate, diatomite, water glass, cement and hydrogen peroxide, and the mixture is stirred, granulated and dried into columnar particles.

Although these microbial carriers can enrich microorganisms to some extent and promote microbial proliferation, the carriers have limited physical and mechanical properties, low durability in use, and strong mass transfer adsorption capacity is also needed.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a preparation method of a microbial carrier by taking sludge as a raw material, which is characterized in that the sludge or sludge settled in a river is combined with materials such as cement, fly ash, zeolite powder, diatomite, bentonite (montmorillonite) and the like for use, so that the microbial proliferation rate of the prepared carrier is obviously improved, and the treatment effect on total nitrogen and nitrate nitrogen in sewage is improved. Specifically, the following technique is used.

A microorganism carrier taking sludge as a raw material is characterized in that the raw material comprises dehydrated sludge powder, cement, fly ash, zeolite powder, diatomite and bentonite, and the weight ratio is (0.5-3): (6-10): (2-6): (3-8): (1-3): 2-4);

the preparation method of the dehydrated mud powder comprises the following steps:

s1, taking the sludge or the silt to remove impurities, and standing for precipitation; the lower layer of settled sludge is left for dewatering until the water content is not more than 85 percent;

s2, drying at 95-105 ℃ to constant weight, cooling, grinding and sieving to obtain a crude dehydrated mud powder product;

s3, adding the biological enzyme solution into the crude dehydrated mud powder, mixing and stirring uniformly, and putting into a closed container to blank for 15-24h to obtain the dehydrated mud powder.

The preparation method of the dehydrated mud powder comprises the following steps: firstly, taking sludge or sludge to remove impurities, standing for precipitation, and then taking the lower-layer precipitated sludge; then filter cloth is used for extrusion dehydration until the water content is 75-85%; and finally drying at 95-105 ℃ to constant weight, cooling to room temperature, grinding and sieving to obtain the finished product.

Because organic matters in the sludge can block the formation of cement gelled substances and influence the long-term strength of the carrier, before the microbial carrier is prepared, after the sludge or sludge powder of the sludge is pretreated by biological enzyme, carbohydrates in the sludge are decomposed to the maximum extent, and proteins are released; the cell of microorganism in the sludge is broken, and the concentration of carbohydrate and polysaccharide in the sludge hydrolysate is obviously improved, so that the molecular structure in the sludge is changed, and the space distance between sludge particles is reduced. The content of effective carbon sources in the dewatered sludge is increased, and the compactness and the bearing capacity of the microbial carrier are improved. Finally, when the microbial carrier is prepared, the dewatered sludge is extruded by external force, the cohesive force among sludge particles is improved, a compact structure with better impermeability is formed, and the purpose of reinforcing the microbial carrier is achieved.

The dewatered sludge powder is prepared by removing impurities from sludge or silt, dewatering, grinding, sieving, and treating with biological enzyme. The biological enzyme used for pretreatment is a complex enzyme product, such as a tyrosin (TerraZyme) developed by Nature Plus Co., Ltd.

The dehydrated mud powder is a carbon source material of an inorganic carrier; the cement has high early strength, stable later strength, good frost resistance and low alkali content, and is mainly used as a binding material of an inorganic carrier; the fly ash is an admixture of an inorganic carrier, so that a large amount of cement and fine aggregate are saved, the water consumption is reduced, and the workability of a concrete mixture is improved; the natural zeolite is aluminosilicate mineral, has porous characteristic, belongs to weak acid cation exchanger, is widely distributed with pore channels and holes in the zeolite and is a porous adsorption material of an inorganic carrier; the diatomite is mainly used for enhancing the water absorption of the inorganic carrier; the bentonite has larger effective pore volume, strong adsorption capacity and adsorption capacity, no toxicity, good thermal stability and high filtering speed, and can effectively enhance the hygroscopicity and expansibility of the inorganic carrier.

Preferably, the raw materials of the microbial carrier comprise dehydrated mud powder, cement, fly ash, zeolite powder, diatomite and bentonite in a weight ratio of 2:8:4:5:2: 3.

More preferably, in the method for preparing the dewatered sludge powder, a screen mesh for grinding and sieving is 45-70 meshes. The optimal screen mesh number is 60 meshes.

Preferably, in the preparation method of the dehydrated mud powder, the biological enzyme solution in the step S3 is prepared by adding water into biological enzyme and diluting the biological enzyme according to the proportion of 1:500, the weight of the biological enzyme solution is 0.3-0.5% of the weight of the crude dehydrated mud powder, and the material sealing time is 20 h.

More preferably, in the method for preparing dehydrated sludge powder, the weight of the biological enzyme solution of step S3 is 0.35% of the weight of the crude dehydrated sludge powder.

Preferably, in the method for preparing dehydrated mud powder, the biological enzyme of step S3 is tyrannose (TerraZyme).

Preferably, the cement is a p.c.32.5 type cement; the density of the fly ash is 2.4g/cm ³ And the water content is 0.5%; the zeolite powder has a density of 1.8-2.2g/cm ³ And the porosity is more than or equal to 50 percent; the content of diatom in the diatomite is not less than 70%, and the content of montmorillonite in the bentonite is not less than 85%.

The patent also provides a preparation method of the microbial carrier taking the sludge as the raw material, which comprises the following steps:

p1, weighing and uniformly mixing the dewatered mud powder, the cement, the fly ash, the zeolite powder, the diatomite and the bentonite, and adding water according to a water-solid ratio of 0.4-0.8 to stir into a mud shape;

p2, pouring into a mould, vibrating, compacting, leveling, maintaining at constant temperature of 20 +/-1 ℃, maintaining at humidity of 90%, sprinkling water for 2-3 times every day during the maintenance period, maintaining for 3-5 days, demoulding, and air drying to obtain the microbial carrier

Compared with the prior art, the invention has the advantages that:

1. according to the microbial carrier disclosed by the invention, the dehydrated sludge powder is used as a carbon source raw material, and the dehydrated and dried sludge powder is pretreated by using the biological enzyme, so that the molecular structure in sludge particles is changed, and the mechanical strength, compactness and other physical properties of the microbial carrier and the sewage purification capacity are improved;

2. the invention adopts sludge as a carbon source material, zeolite powder with a porous structure and a cement binding material to prepare the high-strength microorganism carrier containing the carbon source, has good physical and mechanical properties, high durability and strong mass transfer adsorption capacity, and can provide a suitable carrier environment for the growth of microorganisms;

3. the carbon release is controllable, a carbon source (an electron donor) is provided for the denitrification process, the microorganism propagation can be promoted to improve the denitrification rate, and finally the effective reduction and control of the total nitrogen of the river are achieved.

Detailed Description

The technical solutions of the present invention will be described clearly and completely below, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The cement selected in the following examples and comparative examples was a composite portland cement of type p.c.32.5, and fly ash having a density of 2.4g/cm was used ³ Water content of 0.5%; the zeolite powder has a density of 1.8-2.2g/cm ³ Porosity ofMore than or equal to 50 percent; the content of diatom in the diatomite is not lower than 70%; the content of montmorillonite in bentonite is not less than 85%.

In the following examples and comparative examples, unless otherwise specified, the raw dehydrated sludge powders were prepared by the following methods:

s2, drying at 100 ℃ to constant weight, cooling, grinding and sieving (60 meshes) to obtain a crude dehydrated mud powder product;

s3, adding a biological enzyme solution with the weight of 0.35 percent of the dehydrated mud powder into the crude dehydrated mud powder, mixing and stirring uniformly, and placing the mixture into a closed container to be sealed for 20 hours to obtain dehydrated mud powder; the biological enzyme is Tanainase (TerraZyme) developed by Nature Plus Limited, is black brown viscous liquid, is nontoxic and easily soluble in water, has a certain special smell, has a pH value of 4.3-5.3, and has the characteristics of no pollution, simple and convenient construction, good water stability and the like. The biological enzyme solution is prepared by mixing biological enzyme and water according to the weight ratio of 1: 500.

In the following examples and comparative examples, unless otherwise specified, the microbial carriers were prepared by the following methods:

p1, weighing and uniformly mixing the dewatered sludge powder, the cement, the fly ash, the zeolite powder, the diatomite and the bentonite, and adding water according to a water-solid ratio of 0.6 to stir into a paste;

p2, pouring into a 10mm × 10mm × 10mm mold, vibrating, compacting, leveling, maintaining at constant temperature of 20 + -1 deg.C with maintaining humidity RH of 90%, sprinkling water to the sample for 2 times every day during the maintenance period, and demolding and air drying after maintaining for 5 days to obtain the microorganism carrier.

Example 1

The raw materials of the microbial carrier prepared in this example are dehydrated mud powder, cement, fly ash, zeolite powder, diatomite and bentonite, and the weight ratio is 2:8:4:5:2: 3.

Example 2

The raw materials of the microbial carrier prepared in this example are dehydrated mud powder, cement, fly ash, zeolite powder, diatomite and bentonite, and the weight ratio is 3:10:2:3:1: 4.

Example 3

The raw materials of the microbial carrier prepared in this example are dehydrated mud powder, cement, fly ash, zeolite powder, diatomite and bentonite, and the weight ratio is 0.5:6:6:8:3: 2.

Example 4

The microorganism carrier prepared in this example had the same raw material composition and weight ratio as those of example 1, except that the weight of the bio-enzyme solution of step S3 in the method for preparing dehydrated sludge powder was 0.5% of the weight of the crude dehydrated sludge powder.

Example 5

The microorganism carrier prepared in this example had the same raw material composition and weight ratio as those of example 1, except that the weight of the bio-enzyme solution of step S3 in the method for preparing dehydrated sludge powder was 0.3% of the weight of the crude dehydrated sludge powder.

Example 6

The microorganism carrier prepared in this example has the same raw material composition and weight ratio as those of example 1, except that the material sealing time of step S3 in the method for preparing dehydrated sludge powder is 24 hours.

Example 7

The microorganism carrier prepared in this example has the same raw material composition and weight ratio as those of example 1, except that the material sealing time of step S3 in the method for preparing dehydrated sludge powder is 15 hours.

Comparative example 1

The microbial carrier prepared by the comparative example comprises dehydrated mud powder, cement, fly ash, zeolite powder, diatomite and bentonite in a weight ratio of 4:8:1:9:1: 1.

Comparative example 2

The microorganism carrier prepared by the comparative example comprises dehydrated mud powder, cement, fly ash, zeolite powder, diatomite and bentonite in a weight ratio of 0.1:12:1:2:4: 6.

Comparative example 3

The microbial carrier prepared by the comparative example has the same raw material composition and weight ratio as those of the microbial carrier prepared by the example 1, except that the cement-removed powder is not treated by biological enzyme, and the preparation method comprises the following steps:

s1, taking sludge or silt to remove impurities, and standing for precipitation; the lower layer of settled sludge is left for dewatering until the water content is not more than 85 percent;

s2, drying at 100 ℃ to constant weight, cooling, grinding and sieving (60 meshes) to obtain the raw material dehydrated mud powder of the microbial carrier of the comparative example.

Comparative example 4

The microorganism carrier prepared in this comparative example had the same composition and weight ratio of raw materials as those of example 2, except that the cement-removed powder was not treated with the bio-enzyme, and the preparation method was the same as that of comparative example 3

Comparative example 5

The microorganism carrier prepared in this comparative example had the same raw material composition and weight ratio as those of example 3 except that the cement-removed powder was not treated with bio-enzyme, and was prepared in the same manner as in comparative example 3

Comparative example 6

The microbial carrier prepared by the comparative example only contains cement, fly ash, zeolite powder, diatomite and bentonite, and the raw materials do not contain dehydrated mud powder, and the weight ratio of the raw materials to the raw materials is 8:4:5:2: 3.

Test example 1: the microbial carriers of the examples and the comparative examples were examined for density, compressive strength, and mass transfer adsorption capacity

The microbial carriers prepared in the above examples and comparative examples were tested for density, compressive strength, and mass transfer adsorption capacity. The density is calculated by the ratio of mass to volume, wherein the volume is measured by a flooding method. The compressive strength was measured by an idelberg digital display type push-pull dynamometer. And (3) measuring the mass transfer performance of the high-strength carbon-containing carrier by adopting a methylene blue adsorption method. The specific test results are shown in table 1 below.

TABLE 1 detection results of density, compressive strength, and mass transfer adsorption capacity of microorganism carrier

As can be seen from the test results in Table 1 above, the sample of the microorganism carriers of examples 1-7 and comparative examples 1, 2 have higher physical and mechanical properties and higher mass transfer adsorption capacity than the unconditioned sample of comparative examples 3-5, and higher than the microorganism carrier of comparative example 6 without added dehydrated mud powder, and the comprehensive physical properties of the sample of the microorganism carrier of example 1 are relatively better.

Test example 2: the sewage purification treatment effects of the examples and comparative examples were examined

The experimental part of denitrification needs activated sludge as a control group. The activated sludge is obtained from a flower mountain sewage treatment plant in Wuhan city, and is firstly centrifuged in a centrifuge (3000r/min), and is repeatedly washed and centrifuged for 2-3 times by using physiological saline, and the centrifuged activated sludge is used for preparing bacterial suspension by using the physiological saline.

A certain sewage sample is selected, the concentration of nitrate nitrogen in the original sewage sample is measured to be 19.4mg/L, the total nitrogen is measured to be 34.1mg/L, 1 piece of the microbial carrier sample prepared in the examples 1-7 and the comparative examples 1-6 is taken and put into a 1L glass bottle with a cover, and 8mL of activated sludge and 800mL of sewage are injected. The test device is placed in a biochemical incubator, the test temperature is controlled at 24 +/-1 ℃, and when the test device runs for about 6 days, the nitrate nitrogen and total nitrogen indexes of each experimental group sequentially reach a stable state. And (3) performing nitrate nitrogen detection by adopting an ultraviolet spectrophotometry, and performing total nitrogen detection by adopting an alkaline potassium persulfate digestion ultraviolet spectrophotometry. The results of the assay are shown in Table 2 below.

TABLE 2 detection results of the purification treatment of wastewater with microbial carriers

As can be seen from Table 2 above, the microbial carrier samples of examples 1 to 7 and comparative examples 1 and 2 all had higher sewage purification ability than the unconditioned samples of examples, and the sewage purification ability of example 1 was relatively higher.

Test example 3: the carbon release rate and the enrichment and reproduction effect of microorganisms of the examples and the comparative examples were examined

The pollutant component of the simulated wastewater used in the test is nitrate nitrogen, and the main removal way is to utilize microorganisms as electron donors and nitrate nitrogen as electron acceptors to perform microbial diffusion under the action of activated sludge. Wherein the initial concentration of nitrate nitrogen is 20mg/L, taking a certain sewage sample, measuring the concentration of nitrate nitrogen in the sewage sample to be 19.4mg/L and the total nitrogen to be 34.1mg/L, taking 1 carrier sample, putting the carrier sample into a 1L glass bottle with a cover, and injecting 8mL of activated sludge and 800mL of sewage. The test device is placed in a biochemical incubator, the test temperature is controlled at 24 +/-1 ℃, the test device runs for 5 days in the reaction device, and the total carbon TOC content, the abundance of microorganisms and the diversity index are detected in the period. Wherein, the TOC detection adopts a nitrogen combustion method, and the relative abundance of the microorganisms adopts a fluorescence quantitative PCR method. The specific results are shown in tables 3 and 4 below.

TABLE 3 Total carbon TOC content test results for wastewater samples

TABLE 4 results of microbial abundance measurements of wastewater samples

Group name	Abundance of microorganisms
		Example 1	1697.8306
Example 2	1868.5621
		Example 3	1733.2354
Example 4	1625.2639
		Example 5	1898.4462
Example 6	1705.4788
		Example 7	1733.5213
Comparative example 1	2104.0483
		Comparative example 2	2145.5214
Comparative example 3	2607.5613
		Comparative example 4	2709.2685
Comparative example 5	2718.6634
		Comparative example 6	2997.9472

From tables 3 and 4 above, it can be seen that the total carbon content and microbial abundance of examples 1-7 and comparative examples 1 and 2 are significantly lower than those of the unconditioned samples after a period of time for each set of microbial carrier samples; the total carbon content, microbial abundance, of example 1 was relatively lower.

Claims

1. A microorganism carrier taking sludge as a raw material is characterized in that the raw material comprises dehydrated sludge powder, cement, fly ash, zeolite powder, diatomite and bentonite, and the weight ratio is (0.5-3): (6-10): (2-6): (3-8): (1-3): 2-4);

s2, drying at 95-105 ℃ to constant weight, cooling, grinding, and sieving with a 45-70 mesh sieve to obtain a dehydrated mud powder crude product;

2. The microorganism carrier taking the sludge as the raw material as claimed in claim 1, wherein the raw material comprises dehydrated sludge powder, cement, fly ash, zeolite powder, diatomite and bentonite, and the weight ratio is 2:8:4:5:2: 3.

3. The microbial carrier using sludge as raw material according to claim 1 or 2, wherein in the preparation method of the dewatered sludge powder, the biological enzyme solution of step S3 is prepared by adding water into biological enzyme and diluting according to a ratio of 1:500, the weight of the biological enzyme solution is 0.3-0.5% of the weight of the crude product of the dewatered sludge powder, and the material-sealing time is 20 h.

4. The microorganism carrier for sludge as claimed in claim 3, wherein in the method for preparing dewatered sludge powder, the weight of the bio-enzyme solution of step S3 is 0.35% of the weight of crude dewatered sludge powder.

5. The microorganism carrier for sludge as claimed in claim 1 or 2, wherein in the method for preparing dewatered sludge powder, the biological enzyme of step S3 is tylosin.

6. The microorganism carrier for sludge as claimed in claim 1 or 2, wherein the water is waterThe mud is P.C.32.5 type cement; the density of the fly ash is 2.4g/cm ³ And the water content is 0.5%; the zeolite powder has a density of 1.8-2.2g/cm ³ And the porosity is more than or equal to 50 percent; the content of diatom in the diatomite is not less than 70%, and the content of montmorillonite in the bentonite is not less than 85%.

7. The method for preparing the microbial carrier using the sludge as the raw material according to claim 1, which comprises the following steps:

p2, pouring into a mould, vibrating, compacting, leveling, maintaining at constant temperature of 20 +/-1 ℃, maintaining at humidity of 90%, sprinkling water for 2-3 times every day during the maintenance period, and demolding and airing after maintaining for 3-5 days to obtain the microbial carrier.