CN113603319A

CN113603319A - Multifunctional bottom mud purifying agent and preparation method and application thereof

Info

Publication number: CN113603319A
Application number: CN202110935097.5A
Authority: CN
Inventors: 谢宇; 曾凡虎; 王晓晨; 谭斌; 李其高; 呙于平; 华珊珊; 倪裳; 黄永炳; 贾君座; 黄福瑶; 徐杰斐
Original assignee: China First Metallurgical Group Co Ltd
Current assignee: China First Metallurgical Group Co Ltd
Priority date: 2021-08-16
Filing date: 2021-08-16
Publication date: 2021-11-05
Anticipated expiration: 2041-08-16
Also published as: CN113603319B

Abstract

The invention provides a multifunctional bottom mud purifying agent and a preparation method and application thereof. The multifunctional bottom mud purifying agent comprises the following components in parts by weight: 30-40 parts of mixed microbial inoculum, 5-15 parts of calcium nitrate, 10-20 parts of ascorbic acid, 10-15 parts of bentonite, 10-20 parts of biochar, 6-15 parts of calcium peroxide and 10-15 parts of phosphorus locking agent; the mixed microbial inoculum is selected from the combination of at least three of photosynthetic bacteria flora, lactic acid bacteria flora, actinomycetes flora and yeast flora. The multifunctional bottom sediment purifying agent provided by the invention can effectively reduce the enrichment of ammonia nitrogen, nitrite, organic phosphorus and inorganic phosphorus in the overlying water body, inhibit the outbreak of anaerobic pathogenic bacteria, has a good treatment effect on heavy metals in the bottom sediment, can obviously reduce the toxicity and inhibition of the heavy metals in the bottom sediment on plants, and shows excellent comprehensive treatment capability on the severely polluted black and odorous water body.

Description

Multifunctional bottom mud purifying agent and preparation method and application thereof

Technical Field

The invention belongs to the technical field of sludge treatment, and particularly relates to a multifunctional bottom mud purifying agent and a preparation method and application thereof.

Background

Along with the rapid development of national economy of China, the living standard of people is continuously improved, and meanwhile, the urban population is continuously increased due to increasingly remarkable urbanization effect. Due to the long-term unreasonable arrangement and utilization of water resources and the messy discharge of industrial and domestic sewage and wastewater, the problem of urban water resource pollution is ubiquitous and increasingly prominent, and the daily life of people and the appearance and appearance of cities are seriously affected. Therefore, the problem of the black and odorous water body is not solved at all.

Among a plurality of treatment methods of black and odorous water, the in-situ remediation technology can directly treat the original rivers and lakes because the polluted bottom mud does not need to be mined and dredged, and is favored by a plurality of experts and scholars.

The in-situ remediation technology of the sediment is mainly divided into three major categories, namely a physical remediation technology, a chemical remediation technology and a biological remediation technology. The physical repair technology mainly comprises methods of covering, water diversion and water regulation, artificial aeration and oxygen increasing and the like, but the method has certain requirements on water body environments (water flow rate, pollution conditions and the like). The chemical remediation technology is mainly characterized in that chemical agents are put into the overlying water or the bottom mud of the black and odorous water body and are subjected to a series of physical and chemical reactions with pollutants, so that the pollutants are removed or separated. However, the chemical repair technology has the biggest problems of high cost and high economic cost in practical application. Bioremediation technology generally means that microbes or plants are inoculated and cultured in the original site, and the toxic and harmful pollutants in water and bottom mud are absorbed, converted or degraded by using the metabolic activities of the microbes or plants so as to be harmless. Although the bioremediation is economical, effective and eco-friendly and is generally accepted by society, the technology has some defects, such as slow growth speed of heavy metal super-accumulation plant species, low heavy metal bioavailability, long phytoremediation period and the like.

In summary, the existing water body treatment methods have certain limitations, and the purpose of simultaneously removing pollutants in the overlying water body and heavy metal in the bottom mud is difficult to realize, so that the requirement of long-term and efficient comprehensive treatment on the black and odorous water body cannot be met.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the multifunctional bottom mud purifying agent which has higher removal rate on ammonia nitrogen and phosphorus in the overlying water body and heavy metal in the bottom mud, can effectively reduce the chemical oxygen demand of the water body and obviously improve the dissolved oxygen content of the water body, and the preparation method thereof.

In order to solve the technical problems, the invention provides a multifunctional bottom mud purifying agent in a first aspect, which comprises the following components in parts by weight: 30-40 parts of mixed microbial inoculum, 5-15 parts of calcium nitrate, 10-20 parts of ascorbic acid, 10-15 parts of bentonite, 10-20 parts of biochar, 6-15 parts of calcium peroxide and 10-15 parts of phosphorus locking agent; the mixed microbial inoculum is selected from the combination of at least three of photosynthetic bacteria flora, lactic acid bacteria flora, actinomycetes flora and yeast flora.

On the basis of the technical scheme, the mixed microbial inoculum consists of a photosynthetic bacteria group, a lactic acid bacteria group, an actinomycete group and a yeast bacteria group.

On the basis of the technical scheme, the mass ratio of the photosynthetic bacteria flora to the lactic acid bacteria flora to the actinomycetes flora to the yeast bacteria flora in the mixed microbial inoculum is (2-5) to (3-7) to (3-6) to (4-8).

On the basis of the technical scheme, the mass ratio of the photosynthetic bacteria flora to the lactic acid bacteria flora to the actinomycetes flora to the yeast bacteria flora in the mixed microbial inoculum is 3:4:4: 5.

The second aspect of the invention provides a preparation method of the multifunctional bottom sediment purifying agent according to the first aspect, which comprises the following steps:

s1, uniformly mixing bentonite, biochar and a mixed microbial inoculum to obtain a first mixture;

s2, uniformly mixing the first mixture with calcium nitrate and ascorbic acid to obtain a second mixture;

s3, uniformly mixing the second mixture with calcium peroxide and a phosphorus locking agent to obtain a third mixture;

and S4, after the water content of the third mixture is adjusted, granulating and drying the third mixture to obtain the multifunctional bottom mud purifying agent.

On the basis of the technical scheme, in the step S1, the mesh number of the bentonite is not less than 600 meshes.

On the basis of the above technical solution, in step S4, the adjusting the water content of the third mixture specifically includes: and adding pure water into the third mixture to adjust the water content of the third mixture to 60-65%.

On the basis of the technical scheme, in the step S4, the drying temperature is 60 ℃, and the drying time is 4 h.

The third aspect of the invention provides application of the multifunctional bottom sediment purifying agent according to the first aspect, wherein the multifunctional bottom sediment purifying agent is subpackaged, put into a polluted river and replaced every 15-20 days.

On the basis of the technical scheme, the adding amount of the multifunctional bottom mud purifying agent is 500-1000 g/m²。

Compared with the prior art, the invention has the beneficial effects that:

(1) in the multifunctional bottom mud purifying agent provided by the invention, the calcium nitrate and the mixed microbial inoculum are used in a combined manner, so that the problem of the nitrate nitrogen content of the overlying water body rising caused by the single use of the calcium nitrate is solved, and the purifying effect of the sludge purifying agent on the bottom mud and the overlying water body is improved; the addition of the biochar can obviously reduce the toxicity and inhibition of heavy metals in the bottom sludge on plants, and has good phosphorus removal effect; calcium peroxide is used as a slow-release oxygen increasing agent, so that the water body is in an aerobic state for a long time, and black and odor are further improved; the bentonite and the ascorbic acid are utilized to improve the slow-release oxygen effect of the purifying agent, prolong the oxygen release period of the purifying agent and ensure a long-term effective aerobic environment; the phosphorus in the bottom sludge is further removed efficiently by using the phosphorus-locking agent, and a covering layer is formed on the bottom sludge of the water body to prevent the bottom sludge from generating secondary pollution.

(2) The multifunctional bottom sediment purifying agent provided by the invention is characterized in that the mixed microbial inoculum is selected from the combination of at least three of photosynthetic bacteria, lactic acid bacteria, actinomycetes and yeast bacteria. The photosynthetic bacteria can decompose and utilize harmful organic matters, sulfides, ammonia and other substances in the sludge; the lactic acid bacteria can take the sugars generated by the photosynthetic bacteria and the yeasts to form lactic acid, so that the outbreak of anaerobic pathogenic bacteria at the bottom layer is inhibited; the actinomycete group can effectively consume the sludge at the bottom of the pond, the residual bait and the excrement of the aquatic animals; the yeast flora can effectively reduce the organic pollutants and the total phosphorus content of the overlying water body and can degrade heavy metals to a certain extent. The flora is used in combination, so that the comprehensive treatment effect of the purifying agent can be improved.

(3) The multifunctional bottom sediment purifying agent provided by the invention can effectively reduce the enrichment of ammonia nitrogen, nitrite, organic phosphorus and inorganic phosphorus in the overlying water body and inhibit the outbreak of anaerobic pathogenic bacteria, and the removal rates of the purifying agent on TP and NH3-N, COD in the overlying water body can respectively reach 96.0%, 96.8% and 88.0% to the maximum. Furthermore, the purifying agent has a good treatment effect on heavy metals in the bottom sediment, the removal rates of cadmium, arsenic, copper and mercury in the bottom sediment can reach 82.8%, 69.1%, 61.1% and 97.9% respectively at most, the toxicity and inhibition of the heavy metals in the bottom sediment on plants can be obviously reduced, and excellent comprehensive treatment capability is shown.

Drawings

FIG. 1 is a flow chart of a preparation method of the multifunctional bottom sediment purifying agent provided by the invention.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, 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.

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

The present invention is further illustrated by the following examples, which are not to be construed as limiting the invention.

According to an exemplary embodiment of the invention, a multifunctional bottom sediment purifying agent is provided, which comprises the following components by mass:

30-40 parts of mixed microbial inoculum, 5-15 parts of calcium nitrate, 10-20 parts of ascorbic acid, 10-15 parts of bentonite, 10-20 parts of biochar, 6-15 parts of calcium peroxide and 10-15 parts of phosphorus locking agent; the mixed microbial inoculum is selected from the combination of at least three of photosynthetic bacteria flora, lactic acid bacteria flora, actinomycetes flora and yeast flora.

The multifunctional bottom mud purifying agent is obtained by optimizing the components, and is based on the following principle:

the mixed microbial inoculum adopted by the invention is selected from at least three of photosynthetic flora, lactic acid flora, actinomycete flora and yeast flora. The photosynthetic bacteria are added, so that harmful organic matters, sulfides, ammonia and other substances in the sludge can be decomposed and utilized when the microbial agent is used for purifying the sludge, the harmful organic matters, sulfides, ammonia and other substances in the sludge are converted into inorganic matters harmless to the environment, and the inorganic matters and the sludge are mixed together to enable the sludge to be converted into a fertilizer with certain fertility; the lactic acid bacteria can take the sugars generated by the photosynthetic bacteria and the yeasts to form lactic acid, so that the outbreak of anaerobic pathogenic bacteria at the bottom layer is inhibited; the actinomycete group can effectively consume the sludge at the bottom of the pond, the residual bait and the excrement of the aquatic animals; the yeast flora can effectively reduce the organic pollutants and the total phosphorus content of the overlying water body and can degrade heavy metals to a certain extent. When the at least three floras are used in combination, the three floras generate a synergistic effect, and the comprehensive treatment capacity of the purifying agent can be remarkably improved.

The combined use of the calcium nitrate and the mixed bacteria agent and the optimal proportion increase the purifying effect of the sludge purifying agent on the bottom sludge and the overlying water body. The ascorbic acid has a remarkable improvement on the oxygen slow-release effect of the composite purifying agent. The oxygen release period of the purifying agent is prolonged, the long-term effective aerobic environment is ensured, and the risk of blocking the pipeline is reduced.

The biochar shows good fixing performance on heavy metals in the bottom mud, and the biological effectiveness of the biochar is generally reduced. The bottom sediment bacterial community is generally influenced by the physicochemical property of the bottom sediment and the change of heavy metals by applying the biochar. The biological carbon can obviously reduce the toxicity and inhibition of heavy metals in the sediment to plants and can obviously reduce the intake of the heavy metals in mollusk tissues.

The calcium peroxide is a slow-release oxygen increasing agent, the oxygen increasing duration can reach 1-2 weeks, calcium hydroxide generated by the reaction can be coated on the surface of calcium peroxide which has not yet reacted, so that the contact surface of the calcium peroxide and water is reduced, the reaction speed of the calcium peroxide and the water is further slowed down to achieve the purpose of slow oxygen increasing, and the water body is in an aerobic state for a long time.

And the phosphorus-locking agent absorbs soluble phosphate in the water body in the process of sinking. When the phosphorus locking agent penetrates through the whole water body, a covering layer can be formed on the bottom sediment of the water body, even if part of soluble phosphate is released again at the bottom of the water body due to the change of the environmental conditions, the covering layer with the thickness of about 1-3 mm can effectively capture the soluble phosphate in time, so that the soluble phosphate cannot be released into the water body again to cause secondary pollution to the water body.

In some preferred embodiments, the multifunctional bottom mud purifying agent comprises the following components: 30-35 parts of mixed microbial inoculum, 5-8 parts of calcium nitrate, 15-17 parts of ascorbic acid, 10-13 parts of bentonite, 13-15 parts of biochar, 7-12 parts of calcium peroxide and 10-12 parts of phosphorus locking agent.

In some preferred embodiments, the mixed bacterial agent consists of a photosynthetic bacteria group, a lactic acid bacteria group, an actinomycete group and a yeast bacteria group. When the four floras are used in combination, the four floras generate synergistic action, and the comprehensive treatment capacity of the purifying agent can be further improved.

In some preferred embodiments, the mass ratio of the photosynthetic bacteria flora, the lactic acid bacteria flora, the actinomycetes flora and the yeast flora in the mixed microbial inoculum is (2-5): (3-7): (3-6): (4-8). Under the condition of the proportion, the matching effect of the four floras is better. More preferably, the mass ratio of the photosynthetic bacteria group, the lactic acid bacteria group, the actinomycete group and the yeast bacteria group in the mixed microbial inoculum is (2-3): 3-5): 4-5): 5-6. Most preferably, in the mixed microbial inoculum, the mass ratio of the photosynthetic bacteria flora, the lactic acid bacteria flora, the actinomycetes flora and the yeast flora is 3:4:4: 5.

The invention also provides a preparation method of the multifunctional bottom sediment purifying agent, as shown in figure 1, the preparation method comprises the following steps:

and S4, adjusting the water content of the third mixture, and granulating and drying the third mixture to obtain the multifunctional bottom mud purifying agent.

In some preferred embodiments, in step S1, the mesh number of the bentonite is not less than 600 mesh. The purpose is to prevent pipelines in a river channel from being blocked due to overlarge particle size of the bentonite, and meanwhile, the mesh number of the bentonite larger than 600 meshes can increase the specific surface area of the bentonite particles, so that the reaction effect of the sediment purifying agent is enhanced.

In some preferred embodiments, in step S4, the adjusting the water content of the third mixture is specifically: and adding pure water into the third mixture to adjust the water content of the third mixture to 60-65%. When the water content of the third mixture is in the range, the medicament can be effectively and uniformly mixed, and the subsequent drying time cannot be influenced due to overhigh water content.

In some preferred embodiments, in step S4, the drying temperature is 60 ℃ and the drying time is 4 h.

The invention also provides application of the multifunctional bottom mud purifying agent prepared by the preparation method, and the multifunctional bottom mud purifying agent is subpackaged, put into a polluted river and replaced every 15-20 days. Preferably, the used scavenger is subjected to a desorption regeneration treatment.

In some preferred embodiments, the multifunctional bottom sediment purifying agent is added in an amount of 500-1000 g/m². The method specifically comprises the following steps: a throwing point is arranged at the upstream of a river with the length less than 500 m; and a throwing point is arranged at the interval of 500 meters in the river with the length of more than 500 meters.

The multifunctional bottom sediment purifying agent and the preparation method thereof will be described in detail below by combining examples, comparative examples and experimental data.

TABLE 1 parts by mass of the ingredients in the formulations of examples 1-9 and comparative examples 1-5

	Mixed bacterial agent	Calcium nitrate	Ascorbic acid	Bentonite clay	Biochar	Calcium peroxide	Phosphorus-locking agent
								Example 1	33	5	17	10	13	12	10
Example 2	30	8	15	12	13	7	12
								Example 3	35	8	16	13	13	8	11
Example 4	40	11	20	12	20	6	10
								Example 5	37	15	12	15	18	15	15
Example 6	33	5	17	10	13	12	10
								Example 7	33	5	17	10	13	12	10
Example 8	33	5	17	10	13	12	10
								Example 9	33	5	17	10	13	12	10
Comparative example 1	33	5	17	10	13	12	10
								Comparative example 2	33	5	17	10	13	12	10
Comparative example 3	33	5	17	10	13	12	10
								Comparative example 4	33	5	17	10	13	12	10
Comparative example 5	33	5	17	10	13	12	10

Example 1

Preparing a multifunctional bottom mud purifying agent according to the mass parts of the components shown in the table 1:

the mixed microbial inoculum consists of photosynthetic bacteria, lactic acid bacteria, actinomycetes and yeast bacteria, and the mass ratio of the photosynthetic bacteria, the lactic acid bacteria, the actinomycetes and the yeast bacteria is 3:4:4: 5.

(1) Uniformly mixing 600-mesh bentonite, biochar and a mixed microbial inoculum to obtain a mixed material A;

(2) uniformly mixing the mixture A with calcium nitrate and ascorbic acid to obtain a mixture B;

(3) and (3) uniformly mixing the mixed material B with calcium peroxide and a high-efficiency phosphorus locking agent, and adding purified water to ensure that the water content of the mixed material B reaches 60-65%. And then, sending the mixture to a granulator for granulation, and finally drying the mixture for 4 hours at the temperature of 60 ℃ to obtain the multifunctional bottom mud purifying agent.

Example 2

The multifunctional bottom sediment purifying agents were prepared by the same preparation method as in example 1, based on the parts by mass of the respective components shown in table 1. The mixed microbial inoculum consists of photosynthetic bacteria, lactic acid bacteria, actinomycetes and yeast bacteria, and the mass ratio of the photosynthetic bacteria, the lactic acid bacteria, the actinomycetes and the yeast bacteria is 2:3:3: 5.

Example 3

The multifunctional bottom sediment purifying agents were prepared by the same preparation method as in example 1, based on the parts by mass of the respective components shown in table 1. The mixed microbial inoculum consists of photosynthetic bacteria, lactic acid bacteria, actinomycetes and yeast bacteria, and the mass ratio of the photosynthetic bacteria, the lactic acid bacteria, the actinomycetes and the yeast bacteria is 3:5:5: 5.

Example 4

The multifunctional bottom sediment purifying agents were prepared by the same preparation method as in example 1, based on the parts by mass of the respective components shown in table 1. The mixed microbial inoculum consists of photosynthetic bacteria, lactic acid bacteria, actinomycetes and yeast bacteria, and the mass ratio of the photosynthetic bacteria, the lactic acid bacteria, the actinomycetes and the yeast bacteria is 2:4:5: 6.

Example 5

The multifunctional bottom sediment purifying agents were prepared by the same preparation method as in example 1, based on the parts by mass of the respective components shown in table 1. The mixed microbial inoculum consists of photosynthetic bacteria, lactic acid bacteria, actinomycetes and yeast bacteria, and the mass ratio of the photosynthetic bacteria, the lactic acid bacteria, the actinomycetes and the yeast bacteria is 3:5:4: 6.

Example 6

The multifunctional bottom sediment purifying agents were prepared by the same preparation method as in example 1, based on the parts by mass of the respective components shown in table 1. Wherein the mixed microbial inoculum consists of photosynthetic bacteria, lactic acid bacteria and actinomycetes, and the mass ratio of the photosynthetic bacteria, the lactic acid bacteria and the actinomycetes is 3:4: 4.

Example 7

The multifunctional bottom sediment purifying agents were prepared by the same preparation method as in example 1, based on the parts by mass of the respective components shown in table 1. Wherein the mixed microbial inoculum consists of a lactic acid bacteria group, an actinomycete group and a yeast bacteria group, and the mass ratio of the lactic acid bacteria group to the actinomycete group to the yeast bacteria group is 4:4: 5.

Example 8

The multifunctional bottom sediment purifying agents were prepared by the same preparation method as in example 1, based on the parts by mass of the respective components shown in table 1. The mixed microbial inoculum consists of photosynthetic bacteria, actinomycetes and yeast bacteria in a mass ratio of 3:4: 5.

Example 9

The multifunctional bottom sediment purifying agents were prepared by the same preparation method as in example 1, based on the parts by mass of the respective components shown in table 1. Wherein the mixed microbial inoculum consists of photosynthetic bacteria flora, lactic acid bacteria flora and yeast flora, and the mass ratio of the photosynthetic bacteria flora, the lactic acid bacteria flora and the yeast flora is 3:4: 5.

Comparative example 1

The multifunctional bottom sediment purifying agents were prepared by the same preparation method as in example 1, based on the parts by mass of the respective components shown in table 1. This comparative example contained no mixed inoculum.

Comparative example 2

The multifunctional bottom sediment purifying agents were prepared by the same preparation method as in example 1, based on the parts by mass of the respective components shown in table 1. Wherein, the mixed microbial inoculum is only the photosynthetic bacteria.

Comparative example 3

The multifunctional bottom sediment purifying agents were prepared by the same preparation method as in example 1, based on the parts by mass of the respective components shown in table 1. Wherein, the mixed microbial inoculum is only the lactic acid bacteria.

Comparative example 4

The multifunctional bottom sediment purifying agents were prepared by the same preparation method as in example 1, based on the parts by mass of the respective components shown in table 1. Wherein the mixed microbial inoculum is only actinomycete group.

Comparative example 5

The multifunctional bottom sediment purifying agents were prepared by the same preparation method as in example 1, based on the parts by mass of the respective components shown in table 1. Wherein the mixed microbial inoculum is only yeast flora.

Application example

The medicine bag containing the multifunctional bottom mud purification agent prepared in example 1 was put into the polluted river channels 1-3 (which were fixed by pine piles to prevent the flow of the same along the river).

After 30 days, various indexes (unit: mg/L) of DO, TP, NH3-N, COD and the like of the overlying water body are detected. Wherein, a DO8500 portable dissolved oxygen meter is used for measuring dissolved oxygen, a potassium dichromate method is used for measuring COD, a sodium reagent photometry method is used for measuring ammonia nitrogen, and an ammonium molybdate spectrophotometry method is used for measuring total phosphorus. And simultaneously, detecting the content (unit: mg/kg) of heavy metals in the bottom mud, wherein the method comprises the steps of determining the cadmium content by using a graphite furnace atomic absorption spectrophotometry, determining the arsenic content by using an atomic fluorescence method, determining the copper content by using a flame atomic absorption spectrophotometry and determining the mercury content by using an atomic fluorescence method. The test results are given in table 2 below:

table 2 water quality index and heavy metal content before and after treatment of river 1-3 with the purifying agent prepared in example 1

According to the table, the average removal rates of the multifunctional bottom sediment purifying agent prepared in the embodiment 1 on TP and NH3-N, COD in the overlying water body respectively reach 95.5%, 96.3% and 87.5%, the average removal rates on cadmium, arsenic, copper and mercury in the bottom sediment respectively reach 81.3%, 73.3%, 59.7% and 96.5%, and the Dissolved Oxygen (DO) in the water body is greatly improved. The multifunctional bottom sediment purifying agent provided by the invention can obviously improve the self-purification capacity of the water body and shows excellent comprehensive treatment capacity.

The same detection method is adopted, the multifunctional bottom sediment purifying agents prepared in the examples 2-9 and the comparative examples 1-5 are utilized to test the water quality index of the overlying water body and the treatment result of the heavy metal content in the bottom sediment, and the related detection results are shown in the following table 3.

TABLE 3 results of treatment of contaminated water bodies with the purifiers of examples 1 to 9 and comparative examples 1 to 5 (% removal)

From the above table, it can be seen that:

the bottom sediment purifying agent of the comparative example 1 does not contain a mixed microbial inoculum, and has the worst comprehensive treatment capability. Compared with example 1, it is used for TP and NH in overlying water body₃The removal rate of N, COD is obviously reduced to 40.1 percent, 49.5 percent and 31.3 percent respectively; meanwhile, the average removal rates of cadmium, arsenic, copper and mercury in the bottom mud are respectively reduced to 40.5%, 37.7%, 31.7% and 69.5%. The result shows that the addition of the mixed microbial inoculum plays a positive role in the treatment of pollutants in the overlying water body and heavy metals in the bottom mud.

The mixed bacteria of the bottom sediment purifiers of the comparative examples 2 to 5 all contain only a single bacteria group, and although the individual treatment indexes are improved compared with the comparative document 1, the comprehensive treatment results are still not ideal.

The treatment results of the multifunctional bottom sediment purifiers prepared in examples 1-9 show that when at least three floras are adopted for combined use, the multifunctional bottom sediment purifiers have better comprehensive treatment capacity on ammonia nitrogen and phosphorus in overlying water bodies and heavy metals in bottom sediment. Compared with the treatment effect of combining three floras in the implementation of 6-9, the treatment effect of combining four floras in the implementation of 1-5 is better, which shows that the four floras generate a synergistic effect when the four floras are used for jointly treating sewage, and the comprehensive treatment capacity of the purifying agent is further improved.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.

Claims

1. The multifunctional bottom mud purifying agent is characterized by comprising the following components in parts by mass:

the mixed microbial inoculum is selected from the combination of at least three of photosynthetic bacteria flora, lactic acid bacteria flora, actinomycetes flora and yeast flora.

2. The multifunctional bottom sediment purifying agent as claimed in claim 1, wherein the mixed microbial inoculum consists of photosynthetic bacteria, lactic acid bacteria, actinomycetes and yeast bacteria.

3. The multifunctional bottom sediment purifying agent as claimed in claim 2, wherein the mass ratio of the photosynthetic bacteria group, the lactic acid bacteria group, the actinomycete group and the yeast bacteria group in the mixed bacteria agent is (2-5): (3-7): (3-6): (4-8).

4. The multifunctional bottom sediment purifying agent as claimed in claim 3, wherein the mass ratio of the photosynthetic bacteria group, the lactic acid bacteria group, the actinomycete group and the yeast bacteria group in the mixed bacteria agent is 3:4:4: 5.

5. A method for preparing the multifunctional bottom mud purifying agent as defined in any one of claims 1-4, comprising the steps of:

6. The method according to claim 5, wherein in step S1, the mesh size of the bentonite is not less than 600 mesh.

7. The method according to claim 5, wherein in step S4, the adjusting the water content of the third mixture is: and adding pure water into the third mixture to adjust the water content of the third mixture to 60-65%.

8. The method according to claim 5, wherein in step S4, the drying temperature is 60 ℃ and the drying time is 4 h.

9. The application of the multifunctional bottom mud purifying agent as defined in any one of claims 1 to 4, wherein the multifunctional bottom mud purifying agent is subpackaged, put into a polluted river and replaced every 15-20 days.

10. The use according to claim 9, wherein the multifunctional bottom sediment purifying agent is put in an amount of 500-1000 g/m²。