CN105907679B

CN105907679B - Composition or composite microbial inoculum for treating waste drilling mud

Info

Publication number: CN105907679B
Application number: CN201610307356.9A
Authority: CN
Inventors: 陈五岭; 于烽
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-05-11
Filing date: 2016-05-11
Publication date: 2019-12-10
Anticipated expiration: 2036-05-11
Also published as: CN105907679A

Abstract

A composition or composite inoculant for treating waste drilling mud. The application provides a composition, a composite microbial inoculum and application thereof. The composition or complex inoculant comprises bacillus subtilis, pseudomonas stutzeri and acinetobacter johnsonii, and the application comprises the treatment of waste drilling mud.

Description

Composition or composite microbial inoculum for treating waste drilling mud

Technical Field

The application belongs to the technical field of oil and gas field environmental protection. In particular, the present application relates to compositions or complex inoculants for treating waste drilling mud.

Background

Waste mud discharged during shale gas drilling is a mixture of crude oil, oil-based mud, and mud additives. Like the water-based slurry, the slurry system contains organic and inorganic compounds such as mineral oil, petroleum sulfonate, lime, calcium alkyl benzene sulfonate, calcium chloride, sodium dichromate, caustic soda, sodium hexametaphosphate, sulfomethyl tannin, iron chromium lignosulfonate, oxidized asphalt, chromium lignite, sulfomethyl phenolic resin, sodium polyacrylate, sulfonated tannin and the like, petroleum pollutants, heavy metal ions and other harmful substances. Unlike water-based mud, oil-based mud uses oil as a dispersion medium, and is a complex multiphase system containing mineral oil, phenolic compounds and the like, main pollutants come from base oil of the oil-based mud and additive bases of main and auxiliary emulsion mud, and currently, commonly used oil bases comprise diesel oil bases, white oil bases and synthetic base oil bases. The aromatic hydrocarbons in base oil diesel have greater bio-toxicity, which can have a significant impact on the local ecological environment if not effectively treated, and are more difficult to treat than water-based muds.

Under natural conditions, the harmful substances are difficult to degrade, and the ecological environment of the soil is seriously harmed. According to the requirement of environmental protection, the abandoned oil-based mud and the oil-based mud drill cuttings are subjected to post-treatment. The traditional modes for treating the waste oil-based mud and the oil-based drilling cuttings comprise incineration treatment, cracking treatment, biodegradation and the like. The prior method for treating the waste drilling mud mainly comprises the following steps: simple landfill treatment, reinjection of safe stratum, solidification, land cultivation and the like, wherein the most widely applied method is to perform solidification treatment on waste drilling mud and then perform ー -step comprehensive utilization.

With the development trend of unconventional natural gas-shale gas raised day by day in China, exploration and development of a large number of shale gas fields follow, and the oil-based mud is required to be used for shale gas development, so that the generation amount of waste oil-based mud is increased. Therefore, the economic and effective treatment of the abandoned drilling oil-based mud of the shale gas field becomes ー hot problems to be solved at present.

Disclosure of Invention

in one aspect, the present application provides a composition comprising Bacillus subtilis, Pseudomonas stutzeri, and Acinetobacter johnsonii.

in another aspect, the present application provides a complex microbial agent comprising Bacillus subtilis, Pseudomonas stutzeri, and acinetobacter johnsonii.

In one embodiment, the complex microbial inoculum consists of the three strains.

In one embodiment, the complex microbial inoculum comprises a culture of the three strains.

On the other hand, the application also relates to a preparation method of the complex microbial inoculum, which comprises the following steps:

Respectively culturing Bacillus subtilis, Pseudomonas stutzeri and Acinetobacter johnsonii; and

Obtaining respective cultures of the strains, and mixing the cultures according to the combination to obtain the composite microbial inoculum.

Optionally, the culture is a solid culture, a semi-solid culture or a liquid culture.

In another aspect, the present application is directed to a method of treating or assisting in the treatment of waste drilling mud comprising:

Throwing the composition or the composite microbial inoculum into the waste drilling mud to be treated for at least 20 days, at least 25 days, at least 30 days, at least 35 days, at least 40 days, at least 45 days, at least 50 days, at least 55 days, at least 60 days, at least 65 days, at least 70 days, at least 75 days, at least 80 days, at least 85 days, at least 90 days, at least 95 days, at least 100 days, at least 105 days, at least 110 days, at least 115 days, at least 120 days, at least 125 days, at least 130 days, at least 135 days, at least 140 days, at least 145 days, at least 150 days, at least 155 days, at least 160 days, at least 165 days, at least 170 days, at least 175 days, or at least 180 days.

in one embodiment, the composition or the complex inoculant is dosed into the waste drilling mud to be treated for at least 30 days or at least 35 days.

In one embodiment, the waste drilling mud is waste oil-based mud or waste water-based mud.

In one embodiment, the waste oil-based mud is waste oil-based mud discharged during shale gas drilling.

In some embodiments, the ambient temperature at the time of treatment is at least 10 ℃, at least 15 ℃, at least 20 ℃, at least 25 ℃, at least 30 ℃ or at least 35 ℃, preferably at least 12 to 30 ℃, 16 to 28 ℃ or 16 to 30 ℃. The temperature in the waste drilling mud to be treated is at least 5 ℃, at least 8 ℃, at least 10 ℃, at least 12 ℃, at least 13 ℃, at least 14 ℃ or at least 15 ℃ lower than ambient temperature during treatment.

In some embodiments, the higher the ambient temperature, the higher the temperature in the waste drilling mud, the more rapidly the strain grows, and the shorter the treatment time. The north treatment time is generally 5-9 months, and when the environmental temperature is at least 20 ℃, the treatment time is at least 40-50 days; when the ambient temperature is at least 25 ℃, the treatment time is at least 30-40 days; when the ambient temperature is at least 30 ℃, the treatment time is at least 20-30 days.

In some embodiments, the pH of the waste drilling mud to be treated is at least 7, at least 8, at least 9, at least 10, at least 11, at least 12, or at least 13.

in some embodiments, the optimal pH value for the growth of the strain in the composite microbial inoculum is between 7 and 9.

In some embodiments, the composition or the complex inoculant is at least 0.5%, at least 0.7%, at least 1%, at least 3%, at least 5%, or at least 7% w/v relative to the amount of the spent drilling mud to be treated.

In one embodiment, the composition or the complex inoculant is in an amount of at least 0.5% or at least 0.7% w/v relative to the amount of the spent drilling mud to be treated.

In another aspect, the present application also relates to the use of solids obtained after treating spent drilling mud with the methods disclosed herein for the remediation of spent drilling mud.

Drawings

Fig. 1 is a photograph of a shale gas well abandoned drilling mud pit treatment process, wherein A is before treatment, B is after adding a complex microbial inoculum and stirring, C is after adding the complex microbial inoculum and stirring, D is after adding the complex microbial inoculum and treatment for 7 days, E is after adding the complex microbial inoculum and treatment for 18 days, and F is after adding the complex microbial inoculum and treatment for 30 days.

FIG. 2 is a photograph showing the treatment process of the waste drilling mud pit of the oil well, wherein A is before treatment, B is after adding the complex microbial inoculum and stirring, C is after adding the complex microbial inoculum and stirring, D is after adding the complex microbial inoculum and treating for 10 days, E is after adding the complex microbial inoculum and treating for 18 days, and F is after adding the complex microbial inoculum and treating for 35 days.

FIG. 3 is a photograph showing the treatment process of the waste drilling mud pit of the gas well, wherein A is before treatment, B is after adding the complex microbial inoculum and stirring, C is after adding the complex microbial inoculum and stirring, D is after adding the complex microbial inoculum and treating for 5 days, E is after adding the complex microbial inoculum and treating for 15 days, and F is after adding the complex microbial inoculum and treating for 30 days.

Detailed description of the invention

The following definitions and methods are provided to better define the present application and to guide those of ordinary skill in the art in the practice of the present application. Unless otherwise indicated, terms are to be understood in accordance with their ordinary usage by those of ordinary skill in the relevant art. All patent documents, academic papers, and other publications cited herein are incorporated by reference in their entirety.

definition of

The term "composition" as used herein, refers to a mixture comprising or consisting of two or more microbial species. If desired, the composition may also include other substances that facilitate storage or activity of the strain, e.g., culture media, trace elements, vitamins, amino acids, broths, etc.

The term "complex microbial preparation" as used herein refers to a microbial preparation comprising two or more species of microorganisms which are not antagonistic to each other, wherein the complex microbial preparation comprises the bacterial strain as an active ingredient, and may further comprise a carrier or excipient, and may further comprise other substances which facilitate the storage or activity of the bacterial strain, for example, a culture medium, trace elements, vitamins, amino acids, broth, and the like. In one embodiment, the agents are generally reasonably compatible.

The term "culture", as used herein, refers to a microbial preparation formed by fermentation of a microbial species on a specific medium under the control of specific process conditions, which comprises essentially the cell population of the microbial species, extracellular metabolites of the microbial species and the medium after fermentation.

The term "drilling mud", drilling fluid, as used herein, refers to a circulating flushing fluid used during drilling to clean the bottom of the well, carry cuttings to the bottom surface, and maintain the drilling operation in progress, and is commonly used in the drilling of oil and gas.

The term "oil-based mud" as used herein refers to a mixture comprising crude oil, oil-based mud, and mud additives, with oil as the dispersion medium, and with mineral oil, petroleum sulfonate, lime, calcium alkyl benzene sulfonate, calcium chloride, sodium dichromate, caustic soda, sodium hexametaphosphate, sulfomethyl tannin, iron chromium lignosulfonate, oxidized asphalt, chrome lignite, sulfomethyl phenolic resin, sodium polyacrylate, sulfonated tannin, and other organic and inorganic compounds, petroleum pollutants, heavy metal ions, and other harmful substances in the mud system; the main contaminants are derived from the base oil and the primary and secondary mud additive bases of oil-based muds, with the oil bases currently in common use including diesel, white and synthetic base oil bases.

The term "water-based mud" as used herein refers to a water-based dispersion medium comprising alkalinity modifiers, fluid loss additives, flocculants, coating agents, inhibitors, lubricants, anti-sloughing agents, flow pattern modifiers, oil retention, plugging materials, soil fines or weighting materials, and the like.

The term "pH", also known as hydrogen ion concentration index, pH value, as used herein, refers to the ratio of the total number of hydrogen ions in a solution to the amount of total material, and refers to the numerical value representing the degree of acidity or basicity of the solution, i.e., the negative of the common logarithm of the hydrogen ion concentration contained.

The term "five day biochemical oxygen demand (BOD ₅)" as used herein refers to the amount of dissolved oxygen in milligrams/liter or percent, ppm, consumed by a microorganism to break down certain oxidizable substances, particularly organic substances, in a volume of water measured at 20 ℃ under oxygen-rich, non-agitated measurement conditions for 5 days as a standard time for measuring BOD.

the term "Chemical Oxygen Demand (COD)" as used herein, refers to the amount of oxidant, expressed as milligrams of oxygen per liter, consumed when a water sample is treated with a certain strong oxidant under certain conditions; the reducing substances in the water sample are oxidized by the chemical oxidizing agent, and then the consumption of oxygen is calculated from the amount of the remaining oxidizing agent.

the term "sulfide", as used herein, refers to divalent sulfur-containing organic compounds, such as hydrogen sulfide (H ₂ S), thioethers (R-S-R), thiophenols/thiols (Ar/R-SH), thioaldehydes (R-CSH), thiocarboxylic acids and disulfides (R-S-S-R), and the like.

The term "volatile phenol" as used herein can be divided into volatile phenol and non-volatile phenol depending on whether the phenol can be distilled off together with water vapor, volatile phenol referring to phenol having a boiling point below 230 ℃.

The term "ammonia nitrogen" as used herein refers to nitrogen present in water in the form of free ammonia (NH ₃) and ammonium ions (NH ⁴⁺).

The term "cyanide" as used herein, refers to compounds bearing a cyano group (CN) wherein the carbon and nitrogen atoms are connected by a triple bond, and is divided into inorganic cyanides and organic cyanides; the inorganic cyanide refers to an inorganic salt containing cyanide ions (CN-), and potassium cyanide and sodium cyanide are common; organic cyanides, which are formed by bonding a cyano group to another carbon atom via a single bond, are classified into nitriles (C — CN) and isonitriles (C — NC), depending on the bonding method, and the cyano group may be referred to as a nitrile group (-CN) or an isonitrile group (-NC).

The term "petroleum-based", as used herein, refers to a mixture of various hydrocarbons (alkanes, alkenes, alkynes, cycloalkanes, aromatics) that can exist in wastewater in a dissolved, emulsified and dispersed state and, upon detection, refers to a substance that is capable of being extracted by carbon tetrachloride and that is not adsorbed by magnesium silicate.

The term "solids" as used herein refers to materials that destroy the colloidal structure of the drilling mud, convert petroleum hydrocarbons and heavy metals in the mud, evaporate water from the mud and then dry.

Detailed Description

In some embodiments, the total effective viable count in the composition or in the composite microbial inoculum is more than or equal to 1 x 10 ⁸ cfu/g.

in some embodiments, the weight parts of the bacillus subtilis culture, the pseudomonas stutzeri culture and the acinetobacter johnsonii culture in the composition, or in the complex inoculant, are:

Bacillus subtilis culture 1-3

Pseudomonas stutzeri culture 1-6

1-6 of Acinetobacter johnsonii culture,

Optionally, the strain culture comprises a strain and a culture medium;

Optionally, the effective viable count of the bacillus subtilis in the bacillus subtilis culture is more than or equal to 1 x 10 ⁸ cfu/g, the effective viable count of the pseudomonas stutzeri in the pseudomonas stutzeri culture is more than or equal to 1 x 10 ⁸ cfu/g, and the effective viable count of the acinetobacter johnsonii in the acinetobacter johnsonii culture is more than or equal to 1 x 10 ⁸ cfu/g;

Optionally, the culture medium is a solid medium, a semi-solid medium, or a liquid medium.

In one embodiment, the weight ratio of the bacillus subtilis culture, the pseudomonas stutzeri culture and the acinetobacter johnsonii culture in the composition or in the complex microbial inoculum is 1:2:2, 1:1.5:2 or 1:1: 1.

Respectively culturing Bacillus subtilis, Pseudomonas stutzeri and Acinetobacter johnsonii; and obtaining respective cultures of the strains, and mixing the cultures according to the combination to obtain the composite microbial inoculum.

In some embodiments, the method for preparing the complex microbial inoculum, wherein the bacillus subtilis culture, the pseudomonas stutzeri culture and the acinetobacter johnsonii culture are mixed by the weight of the respective cultures of the strains, and the weight parts of the bacillus subtilis culture, the pseudomonas stutzeri culture and the acinetobacter johnsonii culture are as follows:

bacillus subtilis culture 1-3

Pseudomonas stutzeri culture 1-6

1-6 of Acinetobacter johnsonii culture;

Optionally, the strain culture comprises a strain and a culture medium;

Optionally, the total effective viable count in the composite microbial inoculum is more than or equal to 1 multiplied by 10 ⁸ cfu/g;

In one embodiment, the complex microbial agent is prepared by mixing the bacillus subtilis culture, the pseudomonas stutzeri culture and the acinetobacter johnsonii culture at a weight ratio of 1:2:2, 1:1.5:2 or 1:1:1, based on the weight of the respective cultures of the strains.

The bacterial species used in the present application are all known bacterial species and can be obtained by conventional screening, commercial means or other means.

In one embodiment, the species described herein is commercially available, for example Bacillus subtilis, which may alternatively be obtained from Western biosciences, Inc. (address: Tokyo Taoise, New county, Shaanxi province: 722300).

In one embodiment, the species described herein is commercially available, for example, Pseudomonas stutzeri may be Pseudomonas stutzeri, alternatively, it may be obtained from Western Violet Biotech, Inc. (address: eastern section of Mei dock David, Bin, Shanxi, province: 722300).

In one embodiment, the species described herein is commercially available, for example, Acinetobacter johnsonii can be Acinetobacter johnsonii (Acinetobacter johnsonii), alternatively, the above-mentioned strain can be obtained from Western Anira purple Biotech, Inc. (address: Toyodo Takeda, Toyobo Dow, New region, West county, Shanxi province: 722300).

in some embodiments, the solid culture medium used for solid culture of the species may be a bran medium, a potato medium, a rice bran medium, a soybean meal medium, or a peanut meal medium.

in some embodiments, the liquid medium for liquid culture for culturing the strain may be beef extract peptone liquid medium, seed medium (composition: 0.5% (w/v) yeast extract, 1% (w/v) tryptone, 0.05% (w/v) potassium dihydrogen phosphate and 0.5% (w/v) sodium chloride), or LB liquid medium.

In some embodiments, the semi-solid medium used for semi-solid culture of the species may be prepared by adding a small amount of a coagulating agent (e.g., 0.2% to 0.5% agar) to a liquid medium.

The culture is mainly composed of extracellular metabolites of microbial species (such as enzymes, polysaccharides, lipids, organic acids, etc.), a culture medium after fermentation, and a microbial species cell population.

In one embodiment, the preparation method of the complex microbial inoculum comprises at least one method or step of the following steps:

1) And (3) shake flask culture: respectively inoculating bacillus subtilis, pseudomonas stutzeri and acinetobacter johnsonii to a beef extract peptone liquid culture medium for shake flask culture, and respectively obtaining bacillus subtilis shake flask strains, pseudomonas stutzeri shake flask strains and acinetobacter johnsonii shake flask strains by culturing for 24-48 hours at 25-35 ℃.

2) Seed tank culture: respectively inoculating the bacillus subtilis shake flask strain, the pseudomonas stutzeri shake flask strain and the acinetobacter johnsonii shake flask strain in the step 1) into a seed culture medium (comprising: 0.5 percent (w/v) yeast extract powder, 1 percent (w/v) tryptone, 0.05 percent (w/v) monopotassium phosphate and 0.5 percent (w/v) sodium chloride are cultured in a seed tank for 24-48 hours at the temperature of 25-35 ℃, and bacillus subtilis seed liquid, pseudomonas stutzeri seed liquid and acinetobacter johnsonii seed liquid are respectively obtained.

3) And (3) inoculating the bacillus subtilis seed solution, the pseudomonas stutzeri seed solution and the acinetobacter johnsonii seed solution in the step 2) into a seed culture medium (consisting of 0.5% (w/v) yeast extract powder, 1% (w/v) tryptone, 0.05% (w/v) potassium dihydrogen phosphate and 0.5% (w/v) sodium chloride according to the inoculation amount of 3-10% (volume percentage) respectively to perform fermentation tank culture, culturing for 24 hours or 48 hours at 25-35 ℃ respectively to obtain bacillus subtilis suspension, pseudomonas stutzeri suspension and acinetobacter johnsonii suspension, and performing microscopic examination on the bacterial suspensions respectively, wherein the effective viable count of the bacterial strains is more than or equal to 1 × 10 ⁹ cfu/mL.

4) Solid culture, namely respectively inoculating the bacillus subtilis suspension, the pseudomonas stutzeri suspension and the acinetobacter johnsonii suspension in the step 3) into a bran culture medium (comprising 10% (w) of rice hulls, 5% (w) of soybean meal and 85% (w) of bran (such as wheat bran) according to the proportion of 5-10% (weight percentage) for solid culture at the culture temperature of 25-35 ℃ for 24 hours, 48 hours or 72 hours to respectively obtain a bacillus subtilis solid culture, a pseudomonas stutzeri solid culture and an acinetobacter johnsonii solid culture, respectively performing microscopic examination on the solid cultures, wherein the effective viable count of bacillus subtilis in the bacillus subtilis solid culture is more than or equal to 1 × 10 ⁸ cfu/g, the effective viable count of pseudomonas stutzeri in the pseudomonas stutzeri solid culture is more than or equal to 1 × 10 cf ⁸ u/g, and the effective count of acinetobacter johnsonii in the acinetobacter stutzeri solid culture is more than or equal to 1 × 10 cfu/g;

The Bacillus subtilis solid culture contains Bacillus subtilis cell group, Bacillus subtilis metabolite (such as lipopeptide, protease, lipase, cellulase, alpha-amylase, lactic acid, etc.), and fermented bran culture medium; the solid culture of Pseudomonas stutzeri contains Pseudomonas stutzeri cell group, metabolite of Pseudomonas stutzeri (such as lipase and oxidase) and fermented bran culture medium; the Acinetobacter johnsonii solid culture contains a population of Acinetobacter johnsonii cells, a metabolite of Acinetobacter johnsonii (e.g., lipase) and a bran medium after fermentation.

5) Respectively drying the bacillus subtilis solid culture, the pseudomonas stutzeri solid culture and the acinetobacter johnsonii solid culture, wherein the drying can be powder spraying drying, vacuum drying or fluidized bed drying, and respectively obtaining a bacillus subtilis solid microbial inoculum, a pseudomonas stutzeri solid microbial inoculum and an acinetobacter johnsonii solid microbial inoculum, the effective viable count of bacillus subtilis in the bacillus subtilis solid microbial inoculum is more than or equal to 1 x 10 ⁸ cfu/g, the effective viable count of pseudomonas stutzeri in the pseudomonas stutzeri solid microbial inoculum is more than or equal to 1 x 10 ⁸ cfu/g, and the effective viable count of acinetobacter johnsonii in the acinetobacter johnsonii solid microbial inoculum is more than or equal to 1 x 10 ⁸ cfu/g.

6) Mixing a bacillus subtilis solid microbial inoculum, an acinetobacter schnei solid microbial inoculum and an acinetobacter johnsonii solid microbial inoculum according to the weight percentage of 1:2:2, 1:1.5:2 or 1:1:1 to obtain a compound microbial inoculum, wherein the total effective viable count in the compound microbial inoculum is more than or equal to 1 multiplied by 10 ⁸ cfu/g.

In one embodiment, the waste drilling mud is waste oil-based mud or water-based mud.

In some embodiments, the water content of the spent drilling mud is at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%.

In one embodiment, the water content of the spent drilling mud is at least 80% or at least 90%.

₂ ₂the oil-based mud mainly comprises oil-phase drilling fluid which is a mixture of oxidized asphalt, organic acid, alkali, a stabilizer and high flash point diesel oil and is usually only mixed with 3-5% of water, and water-in-oil emulsified drilling fluid (inverse drilling fluid) which contains various additives for emulsifying and stabilizing water, wherein the maximum water content of the system can reach 50%.

In some embodiments, the end of the treatment of the waste slurry is judged according to the concrete physicochemical indexes of the slurry, and the apparent judgment standard is generally that the water content of the slurry is reduced to a certain degree (for example, below 45%), the surface of the pool bottom is cracked, people can not sink when standing, and the like, or the treatment can be stopped after the water content is reduced to expose the surface of the pool bottom, and other methods are adopted for treatment. Since there is no national standard of unity, the specific index of processing eligibility is specified by the acceptance party.

in one embodiment, the environment temperature is 12-30 ℃, 16-28 ℃ or 16-30 ℃, the waste drilling mud to be treated is treated in situ and in the open air, the water content of the waste drilling mud to be treated is 80% -90% or at least 90%, and the pH value of the waste drilling mud to be treated is 13 or 11-12. Before adding the composite microbial inoculum, mechanical equipment such as a long-arm excavator is used for stirring the waste drilling mud, then the composite microbial inoculum and the waste drilling mud to be treated are put into the waste drilling mud to be treated according to the w/v ratio of at least 0.5% or at least 0.7%, mechanical equipment such as the long-arm excavator is used for stirring, the treatment is carried out for 30 days or 35 days, the water content of the treated mud is reduced to below 45% after the treatment is finished, the compressive strength of solid phase solids in a treated mud tank reaches 1MPa, and surface pollutants reach the requirements of harmless and safe landfill treatment.

The solid obtained after treatment and the measurement index and the measurement method in the leachate are as follows:

and (3) pH value measurement: GB 6920 and 1986 glass electrode method for measuring pH value of water;

Measuring five-day biochemical oxygen demand (BOD ₅), namely measuring the five-day biochemical oxygen demand (BOD ₅) of the HJ 505-;

Chemical Oxygen Demand (COD) determination: GB 11914 and 1989 a dichromate method for determining the chemical oxygen demand of water;

And (3) measuring the sulfide content: iodine measuring method for HJ/T60-2000 water quality sulfide;

And (3) volatile phenol content determination: 4-aminoantipyrine spectrophotometry for measuring HJ 503-2009 water volatile phenol;

And (3) ammonia nitrogen content determination: HJ 537-2009 ammonia nitrogen determination distillation-neutralization titration method for water quality;

Determination of the total cyanide content: HJ 484-2009 water quality cyanide determination volumetric method and spectrophotometry;

And (3) petroleum content determination: HJ 637-2012 water quality infrared spectrophotometry for determining petroleum and animal and plant oils;

And (3) measuring the content of copper and zinc: GB/T17138-1997 determination of the soil quality of copper and zinc by flame atomic absorption spectrophotometry;

And (3) determination of cadmium content: GB/T17141-1997 determination of lead and cadmium in soil quality by graphite furnace atomic absorption spectrophotometry;

And (3) determination of chromium content: GB/T17137-1997 determination of total chromium in soil mass by flame atomic absorption spectrophotometry;

And (3) mercury content determination: part 1 of an atomic fluorescence method for measuring total mercury, total arsenic and total lead in the soil quality of GB/T22105.1-2008: measuring total mercury in soil;

And (3) measuring the arsenic content: part 2 of an atomic fluorescence method for measuring total mercury, total arsenic and total lead in the soil quality of GB/T22105.2-2008: measuring total arsenic in soil;

And (3) lead content determination: part 3 of an atomic fluorescence method for measuring total mercury, total arsenic and total lead in the soil quality of GB/T22105.3-2008: measuring total lead in soil;

and (3) nickel content determination: GBT 17139-1997 soil mass nickel determination flame atomic absorption spectrophotometry;

B content determination: NY/T149-1990 effective boron determination method for soil.

and (3) barium content determination: GB/T15506 and 1995 water quality barium determination atomic absorption spectrophotometry;

And (3) measuring the selenium content: GB/T15505 & 1995 & ltwater & gt, and determination of selenium in water by using atomic absorption spectrophotometry in a graphite furnace.

The reference standard of harmless and safe landfill for treating the waste drilling mud is the soil environment quality standard GB15618-2008, and the third-level soil standard.

accordingly, the present application provides a composition or composite microbial inoculum for treating waste drilling mud having at least one of the following advantages:

(1) In the composition or the composite microbial inoculum, each strain can adapt to the natural environment and is inoculated into waste drilling mud, and the selected strains can survive to perform metabolic activity and waste drilling mud treatment.

(2) In the composition or the composite microbial inoculum, each strain is a dominant strain, can adapt to the environment of waste drilling mud, and metabolites of the strain, such as lipopeptide, protease, lipase and the like, are beneficial to treating the waste drilling mud.

(3) in the composition or the composite microbial inoculum, the strain proportion is reasonable, and the respective degradation advantages can be exerted.

(4) The composite microbial inoculum is used for in-situ treatment in the waste drilling mud tank, so that the treatment cost is low, the treatment process is simple, the harmless treatment effect is good, and the economic benefit and the social benefit are remarkable.

(5) The application can be applied to waste oil-based mud discharged in shale gas drilling construction, and can also be oil-based mud and water-based mud discharged in drilling of a common oil and gas field, so that the problems of environmental pollution and ecological damage generated in the oil and gas exploitation process can be solved, and the application has important significance in pollution remediation.

(6) In the composition or the composite microbial inoculum, each strain converts harmful ingredients into substances such as carbon sources and nitrogen sources which can be utilized by plants, so that various nutrient elements in soil can be supplemented, and the growth of the plants is promoted.

(7) In the composition or the composite microbial inoculum, each strain adsorbs or converts heavy metal in the waste oil-based mud, so that the biotoxicity in solid matters is reduced.

In some embodiments, the compositions or composite inoculants provided herein for treating waste drilling mud achieve at least one of the following effects:

(1) After the composition or the composite microbial inoculum is used for treating the waste oil-based mud, the content of each heavy metal in the solid phase is obviously reduced, and the content of each heavy metal is reduced by at least 15 percent, and specific data are shown in an example. Wherein the cadmium content is reduced by at least 70%, the lead content is reduced by at least 90%, the arsenic content is reduced by at least 15%, and no mercury is detected, relative to the solid phase prior to treatment.

(2) After the composition or the composite microbial inoculum is used for treating the waste oil-based mud, the pH value, BOD ₅, COD, sulfide content, volatile phenol content and petroleum content in the solid-phase leachate are all significantly reduced, and specific data refer to examples, wherein compared with BOD ₅ in the solid-phase leachate before treatment, the COD is reduced by at least 30%, the petroleum content is reduced by at least 20%, and no sulfide or volatile phenol is detected.

(3) After the composition or the composite microbial inoculum is used for treating the waste oil-based mud, the content of each heavy metal in the solid-phase leachate is obviously reduced, and the content of each heavy metal is reduced by at least 8 percent, and specific data refer to examples. Wherein the mercury content is reduced by at least 65% and the nickel content is reduced by at least 75% relative to the mercury content in the solid phase leach before treatment, and no copper, zinc, cadmium, lead, chromium, arsenic and barium are detected.

(4) After the composition or the composite microbial inoculum is used for treating the waste oil-based mud, the water content in the mud pit is reduced to below 45 percent, below 40 percent, below 35 percent or below 30 percent, and preferably below 45 percent.

(5) After the composition or the composite microbial inoculum is used for treating the waste oil-based mud, the compressive strength of a solid-phase solidified body in a mud pit can reach at least 1MPa, at least 1.5MPa or at least 2MPa, and preferably at least 1 MPa.

The following examples are for the purpose of illustration only and are not intended to limit the scope of the present application.

examples

Example 1 treatment of shale gas well waste oil-based mud

and performing innocent treatment on about 1000 cubic meters of waste oil-based mud generated by a certain shale gas well.

The shale gas well site is located at the edge of a maowu desert, the surrounding geomorphic environments are sand dunes and few farmlands, the drilling and the communication are carried out for nearly one year after drilling, well washing waste liquid on the upper layer of a mud pit is basically and naturally evaporated, no obvious seepage liquid is separated out in the pit, an air-drying layer with the surface of 2-3 cm is arranged on the surface of the mud pit, the water content of mixed waste below the air-drying layer is 80-90%, the pH value is 13, and the shale gas well site is in a viscose shape in a physical state. The environmental temperature before treatment is 30 ℃, the temperature in the mud pit is 17 ℃, the composite microbial inoculum is added into the waste mud pit and is stirred for treatment, the environmental temperature during the treatment is 12-30 ℃, the treatment monitoring time is 30 days, and two rainfall processes exist in the treatment period.

3) and (3) respectively inoculating the bacillus subtilis seed liquid, the pseudomonas stutzeri seed liquid and the acinetobacter johnsonii seed liquid in the step 2) into a seed culture medium (consisting of 0.5% (w/v) yeast extract powder, 1% (w/v) tryptone, 0.05% (w/v) potassium dihydrogen phosphate and 0.5% (w/v) sodium chloride according to the inoculation amount of 3-10% (volume percentage) for fermentation tank culture, respectively culturing for 48 hours at 25-35 ℃ to respectively obtain bacillus subtilis suspension, pseudomonas stutzeri suspension and acinetobacter johnsonii suspension, and respectively carrying out microscopic examination on the bacterial suspensions, wherein the effective viable count of the strains is more than or equal to 1 × 10 ⁹ cfu/mL.

4) And (3) solid culture, namely respectively inoculating the bacillus subtilis suspension, the pseudomonas stutzeri suspension and the acinetobacter johnsonii suspension in the step 3) into a bran culture medium (comprising 10% (w) of rice hulls, 5% (w) of soybean meal and 85% (w) of bran (such as wheat bran) according to a proportion of 5-10% by weight for solid culture at a culture temperature of 25-35 ℃ for 72 hours to respectively obtain a bacillus subtilis solid culture, a pseudomonas stutzeri solid culture and an acinetobacter johnsonii solid culture, and respectively performing microscopic examination on the solid cultures, wherein the effective viable count of bacillus subtilis in the bacillus subtilis solid culture is more than or equal to 1 x 10 ⁸ cfu/g, the effective viable count of pseudomonas stutzeri in the pseudomonas stutzeri solid culture is more than or equal to 1 x 10 ⁸ cfu/g, and the effective viable count of acinetobacter johnsonii in the acinetobacter johnsonii solid culture is more than or equal to 1 x 10 cf 10 ⁸ u/g.

5) And (2) performing powder spraying and drying on the bacillus subtilis solid culture, the pseudomonas stutzeri solid culture and the acinetobacter johnsonii solid culture in the step 4) to respectively obtain a bacillus subtilis solid microbial agent, a pseudomonas stutzeri solid microbial agent and an acinetobacter johnsonii solid microbial agent, wherein the effective viable count of bacillus subtilis in the bacillus subtilis solid microbial agent is more than or equal to 1 × 10 ⁸ cfu/g, the effective viable count of pseudomonas stutzeri in the pseudomonas stutzeri solid microbial agent is more than or equal to 1 × 10 ⁸ cfu/g, the effective viable count of acinetobacter johnsonii in the acinetobacter johnii solid microbial agent is more than or equal to 1 × 10 ⁸ cfu/g, and mixing the bacillus subtilis solid microbial agent, the pseudomonas stutzeri solid microbial agent and the acinetobacter johnii solid microbial agent according to the ratio (weight percentage) of 1:2:2 to obtain the composite microbial agent, wherein the total effective.

6) Conveying the composite microbial inoculum prepared in the step 5) to a waste mud pit near a well site for adding, and uniformly stirring the waste mud pit by using mechanical equipment such as a long-arm excavator and the like before adding. The inoculation amount of the composite microbial inoculum relative to the waste drilling mud to be treated is 0.5% w/v (ton/cubic meter), the composite microbial inoculum and the waste drilling mud to be treated are uniformly stirred by using mechanical equipment such as a long-arm excavator after being added, and the mixture is subjected to harmless treatment for 30 days after being stirred.

After 30 days of treatment, the contents of heavy metals (copper, zinc, cadmium, lead, chromium, mercury, arsenic, nickel and boron) in the solid phase in the treated drilling mud pit are measured, and the contents of relevant physicochemical indexes (chemical oxygen demand (COD), five-day biochemical oxygen demand (BOD ₅), pH value, sulfide content, ammonia nitrogen content, total cyanide content and petroleum content) and heavy metals (copper, zinc, cadmium, lead, chromium, mercury, arsenic, nickel, barium and selenium) in the solid phase leachate are measured.

The preparation method of the solid phase leaching solution refers to a horizontal oscillation method for preparing the solid waste leaching toxicity leaching method of HJ 557-2010.

As shown in figures 1A to 1F, in the harmless treatment process, the colloid state of the waste slurry can be rapidly destroyed after the waste slurry is acted by the complex microbial inoculum, the obvious solid-liquid separation occurs in a slurry tank, the volatilization speed of water in the slurry is greatly accelerated, the pH value of a water phase is rapidly reduced, and meanwhile, heavy metal ions and chloride ions dissolved in the water phase are retained in the solid phase of the slurry and are continuously degraded and converted by the action of microorganisms.

The results of the determination of the heavy metal content in the solid phase in the drilling mud pit after the treatment are shown in table 1, and compared with the results before the treatment, the contents of various heavy metals are remarkably reduced, and the biotoxicity is reduced. Compared with the solid phase before treatment, the content of copper in the treated solid phase is reduced by 42.52%, the content of zinc is reduced by 41.88%, the content of cadmium is reduced by 90.75%, the content of lead is reduced by 96.53%, the content of chromium is reduced by 83.26%, the content of arsenic is reduced by 18.71%, the content of nickel is reduced by 40.48%, the content of boron is reduced by 33.92%, and mercury is not detected in the solid phase.

TABLE 1 detection results of solid-phase heavy metal content before and after treatment

"/" indicates no detection.

After the treatment, the detection results of various physicochemical factors in the solid-phase leachate are shown in table 2, compared with the solid-phase leachate before the treatment, the pH value, BOD ₅, COD, sulfide content, volatile phenol content and petroleum content are obviously reduced, and the ammonia nitrogen content is obviously increased, wherein compared with the solid-phase leachate before the treatment, the BOD ₅ in the treated solid-phase leachate is reduced by 69.11%, the COD is reduced by 64.75%, the petroleum content is reduced by 83.34%, and the sulfide and volatile phenol are not detected, and the ammonia nitrogen content is increased by 50.88%.

Table 2 detection results of physicochemical factors in solid-phase leachate before and after treatment

"/" indicates no detection.

The heavy metal content in the solid phase leachate was also significantly reduced compared to before treatment, and the results are shown in table 3. Compared with the solid-phase leachate before treatment, the mercury content in the treated solid-phase leachate is reduced by 86.67%, the nickel content is reduced by 77.38%, the selenium content is reduced by 8.70%, and copper, zinc, cadmium, lead, chromium, arsenic and barium are not detected.

Table 3 detection results of heavy metal content in solid-phase leachate before and after treatment

"/" indicates no detection.

After the composite microbial inoculum is treated, the water content in the slurry pool is reduced to below 45 percent, the compressive strength of a slurry solid-phase solidified body can reach 1MPa, and the surface pollutants can finally meet the requirements of harmless and safe landfill treatment. Harmful components in the treated mud are converted into substances such as carbon sources, nitrogen sources and the like which can be utilized by various plants, so that the biological toxicity is reduced, various nutrient elements in the soil can be supplemented, and the plants are promoted to absorb and grow. And (4) leveling the mud pit after the mud pit is processed, wherein the well site surface is clean and free of impurities such as residual mud and the like after leveling, and the thickness of the covering soil on the processed mud pit is more than 30 cm. Spreading mixed seeds of twisted strips, amorpha fruticosa, artemisia desertorum, alfalfa and the like after the surface of the mud pit is leveled for 30 days, and performing vegetation recovery.

example 2 treatment of oil well waste oil based mud

About 800 cubic meters of waste oil-based mud produced from a well is treated for innocuousness.

The oil well field is located beside a village, the surrounding landform environment is in a ploughed farmland, drilling and communication are completed, the pH value of bottom layer slurry is 13-14, the physical state is viscose, the environmental temperature before treatment is 30 ℃, the water temperature of the upper layer of a slurry pool is 18 ℃, and the bottom layer slurry is 8-10 ℃. The water content of the waste slurry after stirring is more than 90%, the pH value is 11-12, the temperature is 15-16 ℃, and the waste slurry is in a dilute colloid state in a physical state. And adding the composite microbial inoculum into a waste slurry pool, stirring and then treating, wherein the environmental temperature is 16-28 ℃ in the treatment period, and the treatment monitoring time is 35 days.

4) And (3) solid culture, namely respectively inoculating the bacillus subtilis suspension, the pseudomonas stutzeri suspension and the acinetobacter johnsonii suspension in the step 3) into a bran culture medium (comprising 10% (w) of rice hulls, 5% (w) of soybean meal and 85% (w) of bran (such as wheat bran) according to a proportion of 5-10% by weight for solid culture at a temperature of 25-35 ℃ for 48 hours to respectively obtain a bacillus subtilis solid culture, a pseudomonas stutzeri solid culture and an acinetobacter johnsonii solid culture, and respectively performing microscopic examination on the solid cultures, wherein the effective viable count of bacillus subtilis in the bacillus subtilis solid culture is more than or equal to 1 x 10 ⁸ cfu/g, the effective viable count of pseudomonas stutzeri in the pseudomonas stutzeri solid culture is more than or equal to 1 x 10 ⁸ cfu/g, and the effective viable count of acinetobacter johnsonii in the acinetobacter johnsonii solid culture is more than or equal to 1 x 10 cf 10 ⁸ u/g.

5) And (2) performing powder spraying and drying on the bacillus subtilis solid culture, the pseudomonas stutzeri solid culture and the acinetobacter johnsonii solid culture in the step 4) to respectively obtain a bacillus subtilis solid microbial agent, a pseudomonas stutzeri solid microbial agent and an acinetobacter johnsonii solid microbial agent, wherein the effective viable count of bacillus subtilis in the bacillus subtilis solid microbial agent is more than or equal to 1 × 10 ⁸ cfu/g, the effective viable count of pseudomonas stutzeri in the pseudomonas stutzeri solid microbial agent is more than or equal to 1 × 10 ⁸ cfu/g, the effective viable count of acinetobacter johnsonii in the acinetobacter johnii solid microbial agent is more than or equal to 1 × 10 ⁸ cfu/g, mixing the bacillus subtilis solid microbial agent, the pseudomonas stutzeri solid microbial agent and the acinetobacter johnii solid microbial agent according to the proportion (weight percentage) of 1:1.5:2 to obtain the composite microbial agent, and the total effective viable count of.

6) Conveying the composite microbial inoculum prepared in the step 5) to a waste mud pit near a well site for adding, and uniformly stirring the waste mud pit by using mechanical equipment such as a long-arm excavator and the like before adding. The inoculation amount of the composite microbial inoculum relative to the waste drilling mud to be treated is 0.7% w/v (ton/cubic meter), the composite microbial inoculum and the waste drilling mud to be treated are uniformly stirred by using mechanical equipment such as a long-arm excavator after being added, and the mixture is subjected to harmless treatment for 35 days after being stirred.

After 35 days of treatment, the contents of heavy metals (copper, zinc, cadmium, lead, chromium, mercury, arsenic, nickel and boron) in the solid phase in the treated drilling mud pit are measured, and the contents of relevant physicochemical indexes (chemical oxygen demand (COD), five-day biochemical oxygen demand (BOD ₅), pH value, sulfide content, ammonia nitrogen content, total cyanide content and petroleum content) and heavy metals (copper, zinc, cadmium, lead, chromium, mercury, arsenic, nickel, barium and selenium) in the solid phase leachate are measured.

The treatment process is as shown in fig. 2A to 2F, in the harmless treatment process, the colloid state of the waste slurry can be rapidly destroyed after the waste slurry is acted by the complex microbial inoculum, the slurry pool has obvious solid-liquid separation, the volatilization speed of the water in the slurry is greatly accelerated, the pH value of the water phase is rapidly reduced, and meanwhile, the heavy metal ions and the chloride ions dissolved in the water phase are retained in the solid phase of the slurry and are continuously degraded and converted by the action of microorganisms.

The results of the determination of the heavy metal content in the solid phase in the drilling mud pit after the treatment are shown in table 4, and compared with the results before the treatment, the contents of various heavy metals are remarkably reduced, and the biotoxicity is reduced. Compared with the solid phase before treatment, the content of copper in the treated solid phase is reduced by 48.49%, the content of zinc is reduced by 61.20%, the content of cadmium is reduced by 71.60%, the content of lead is reduced by 95.84%, the content of chromium is reduced by 91.62%, the content of arsenic is reduced by 19.05%, the content of nickel is reduced by 38.23%, the content of boron is reduced by 59.84%, and mercury is not detected in the solid phase.

TABLE 4 detection results of solid-phase heavy metal content before and after treatment

"/" indicates no detection.

After the treatment, the detection results of various physicochemical factors in the solid-phase leachate are shown in table 5, and compared with the solid-phase leachate before the treatment, the pH value, BOD ₅, COD, sulfide content, volatile phenol content and petroleum content are obviously reduced, wherein compared with the solid-phase leachate before the treatment, BOD ₅ in the solid-phase leachate after the treatment is reduced by 45.65%, COD is reduced by 25.96%, ammonia nitrogen content is reduced by 6.61%, petroleum content is reduced by 74.50%, and sulfide and volatile phenol are not detected.

TABLE 5 detection results of physicochemical factors in solid-phase leachate before and after treatment

"/" indicates no detection.

The heavy metal content in the solid phase leachate was also significantly reduced compared to before treatment, and the results are shown in table 6. Compared with the solid-phase leachate before treatment, the mercury content in the treated solid-phase leachate is reduced by 66.67%, the nickel content is reduced by 84.62%, the selenium content is reduced by 12.12%, and copper, zinc, cadmium, lead, chromium, arsenic and barium are not detected in the solid-phase leachate.

Table 6 detection results of heavy metal content in solid-phase leachate before and after treatment

"/" indicates no detection.

Example 3 treatment of gas well waste oil-based mud

About 200 cubic meters of waste oil-based mud produced by a gas well is subjected to innocent treatment. The well site is located in loess hilly land, and peripheral landform environment is the farmland, has accomplished and has handed over about half a year, and bottom mud pH value is 12, and the physical state is the viscose body, and about 100 ~ 150t well testing waste liquid in upper strata, surface are thicker former oil reservoir, and ambient temperature is 25 ℃ before handling, and the temperature is 13 ℃ in the mud pond. After stirring, the water content of the waste slurry is more than 90%, the pH value is 11-12, the temperature is 12 ℃, and the waste slurry is in a dilute colloid state in a physical state. And adding the composite microbial inoculum into a waste slurry pool, stirring and then treating, wherein the environmental temperature is 16-30 ℃ during the treatment period, and the treatment monitoring time is 30 days.

3) And (3) respectively inoculating the bacillus subtilis seed liquid, the pseudomonas stutzeri seed liquid and the acinetobacter johnsonii seed liquid in the step 2) into a seed culture medium (consisting of 0.5% (w/v) yeast extract powder, 1% (w/v) tryptone, 0.05% (w/v) potassium dihydrogen phosphate and 0.5% (w/v) sodium chloride according to the inoculation amount of 3-10% (volume percentage) for fermentation tank culture, respectively culturing for 24 hours at 25-35 ℃ to respectively obtain bacillus subtilis suspension, pseudomonas stutzeri suspension and acinetobacter johnsonii suspension, and respectively performing microscopic examination on the bacterial suspensions to respectively obtain the effective viable count of the strains which is more than or equal to 1 × 10 ⁹ cfu/mL.

4) And (3) solid culture, namely respectively inoculating the bacillus subtilis suspension, the pseudomonas stutzeri suspension and the acinetobacter johnsonii suspension in the step 3) into a bran culture medium (comprising 10% (w) of rice hulls, 5% (w) of soybean meal and 85% (w) of bran (such as wheat bran) according to a proportion of 5-10% by weight for solid culture at a temperature of 25-35 ℃ for 24 hours to respectively obtain a bacillus subtilis solid culture, a pseudomonas stutzeri solid culture and an acinetobacter johnsonii solid culture, and respectively performing microscopic examination on the solid cultures, wherein the effective viable count of bacillus subtilis in the bacillus subtilis solid culture is more than or equal to 1 x 10 ⁸ cfu/g, the effective viable count of pseudomonas stutzeri in the pseudomonas stutzeri solid culture is more than or equal to 1 x 10 ⁸ cfu/g, and the effective viable count of acinetobacter johnsonii in the acinetobacter johnsonii solid culture is more than or equal to 1 x 10 cf 10 ⁸ u/g.

5) And (2) performing powder spraying and drying on the bacillus subtilis solid culture, the pseudomonas stutzeri solid culture and the acinetobacter johnsonii solid culture in the step 4) to respectively obtain a bacillus subtilis solid microbial agent, a pseudomonas stutzeri solid microbial agent and an acinetobacter johnsonii solid microbial agent, wherein the effective viable count of bacillus subtilis in the bacillus subtilis solid microbial agent is more than or equal to 1 × 10 ⁸ cfu/g, the effective viable count of pseudomonas stutzeri in the pseudomonas stutzeri solid microbial agent is more than or equal to 1 × 10 ⁸ cfu/g, the effective viable count of acinetobacter johnsonii in the acinetobacter johnii solid microbial agent is more than or equal to 1 × 10 ⁸ cfu/g, mixing the bacillus subtilis solid microbial agent, the pseudomonas stutzeri solid microbial agent and the acinetobacter johnii solid microbial agent according to the proportion (weight percentage) of 1:1:1, and obtaining the composite microbial agent, wherein the total effective viable count.

The treatment process is as shown in fig. 3A to 3F, in the harmless treatment process, the colloid state of the waste slurry can be rapidly destroyed after the waste slurry is acted by the complex microbial inoculum, the obvious solid-liquid separation occurs in the slurry tank, the volatilization speed of the water in the slurry is greatly accelerated, the pH value of the water phase is rapidly reduced, and meanwhile, the heavy metal ions and the chloride ions dissolved in the water phase are retained in the solid phase of the slurry and are continuously degraded and converted by the action of microorganisms.

The results of the determination of the heavy metal content in the solid phase in the drilling mud pit after the treatment are shown in table 7, and compared with the results before the treatment, the contents of various heavy metals are remarkably reduced, and the biotoxicity is reduced. Compared with the solid phase before treatment, the content of copper in the treated solid phase is reduced by 51.19%, the content of zinc is reduced by 59.14%, the content of cadmium is reduced by 75.00%, the content of lead is reduced by 92.23%, the content of chromium is reduced by 90.12%, the content of arsenic is reduced by 60.71%, the content of nickel is reduced by 37.96%, the content of boron is reduced by 59.60%, and mercury is not detected in the solid phase.

TABLE 7 detection results of solid-phase heavy metal content before and after treatment

"/" indicates no detection.

After the treatment, the detection results of various physical and chemical factors in the solid-phase leachate are shown in Table 8, and compared with the solid-phase leachate before the treatment, the pH value, BOD ₅, COD, sulfide content, volatile phenol content and petroleum content are obviously reduced, and the ammonia nitrogen content is obviously increased, wherein compared with the solid-phase leachate before the treatment, the BOD ₅ in the solid-phase leachate after the treatment is reduced by 31.76%, the COD is reduced by 42.18%, the petroleum content is reduced by 68.75%, and the ammonia nitrogen content is increased by 50.60% without detecting sulfide and volatile phenol

Table 8 results of measurement of physicochemical factors in solid-phase leachate before and after treatment

"/" indicates no detection.

The heavy metal content in the solid phase leachate was also significantly reduced compared to before treatment, and the results are shown in table 9. Compared with the solid-phase leachate before treatment, the mercury content in the treated solid-phase leachate is reduced by 92.86%, the nickel content is reduced by 82.35%, the selenium content is reduced by 46.43%, and copper, zinc, cadmium, lead, chromium, arsenic and barium are not detected in the solid-phase leachate.

Table 9 detection results of heavy metal content in solid-phase leachate before and after treatment

"/" indicates no detection.

Although the invention has been described in detail hereinabove with respect to a general description and specific embodiments thereof, it will be apparent to those skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims

1. A complex microbial agent for treating waste drilling mud, which consists of a culture of Bacillus subtilis, a culture of Pseudomonas stutzeri and a culture of Acinetobacter johnsonii, wherein

The strain culture comprises a strain and a culture medium, wherein the effective viable count of the bacillus subtilis in the bacillus subtilis culture is more than or equal to 1 multiplied by 10 ⁸ cfu/g, the effective viable count of the pseudomonas stutzeri in the pseudomonas stutzeri culture is more than or equal to 1 multiplied by 10 ⁸ cfu/g, and the effective viable count of the acinetobacter johnsonii in the acinetobacter johnsonii culture is more than or equal to 1 multiplied by 10 ⁸ cfu/g;

The weight ratio of the Bacillus subtilis culture, the Pseudomonas stutzeri culture, and the Acinetobacter johnsonii culture, based on the weight of the strain culture, is (1 ~ 3): (1 ~ 6): (1 ~ 6).

2. The composite bacterial preparation of claim 1, wherein the total effective viable count of the composite bacterial preparation is more than or equal to 1 x 10 ⁸ cfu/g.

3. The complex microbial agent of claim 1, wherein the weight ratio of said bacillus subtilis culture, said pseudomonas stutzeri culture and said acinetobacter johnsonii culture is 1:2:2, 1:1.5:2 or 1:1: 1.

4. The complex microbial agent of any one of claims 1 to 3, wherein the medium is a solid medium, a semi-solid medium or a liquid medium.

5. A method for preparing a complex microbial inoculum of any one of claims 1 to 4, which comprises the following steps:

And obtaining respective cultures of the strains, and mixing the respective cultures of the strains according to the combination to obtain the composite microbial inoculum.

6. the method of claim 5, wherein the culture is a solid culture, a semi-solid culture, or a liquid culture.

7. A method of treating or assisting in the treatment of waste drilling mud, comprising:

Throwing the composite microbial inoculum of any one of claims 1 to 4 into the waste drilling mud to be treated for at least 20 days, wherein the inoculation amount of the composite microbial inoculum relative to the waste drilling mud to be treated is at least 0.5% w/v.

8. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 25 days.

9. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 30 days.

10. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 35 days.

11. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 40 days.

12. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 45 days.

13. the method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 50 days.

14. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 55 days.

15. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 60 days.

16. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 65 days.

17. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 70 days.

18. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 75 days.

19. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 80 days.

20. The method of claim 7, wherein the composite microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 85 days.

21. the method of claim 7, wherein the composite bacterial agent of any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 90 days.

22. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 95 days.

23. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 100 days.

24. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 105 days.

25. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 110 days.

26. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 115 days.

27. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 120 days.

28. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 125 days.

29. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 130 days.

30. the method of claim 7, wherein the composite bacterial agent of any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 135 days.

31. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 140 days.

32. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 145 days.

33. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 150 days.

34. The method of claim 7, wherein the complex microbial inoculum of any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 155 days.

35. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 160 days.

36. The method of claim 7, wherein the complex microbial inoculum of any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 165 days.

37. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 170 days.

38. the method of claim 7, wherein the complex microbial inoculum of any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 175 days.

39. The method of claim 7, wherein the complex microbial inoculum according to any one of claims 1 to 4 is thrown into the waste drilling mud to be treated for at least 180 days.

40. the method of claim 7 wherein the inoculum size of the complex inoculum relative to the spent drilling mud to be treated is at least 0.7% w/v.

41. The method of claim 7 wherein the inoculum size of the complex inoculum relative to the spent drilling mud to be treated is at least 1% w/v.

42. The method of claim 7 wherein the inoculum size of the complex inoculum relative to the spent drilling mud to be treated is at least 3% w/v.

43. The method of claim 7 wherein the inoculum size of the complex inoculum relative to the spent drilling mud to be treated is at least 5% w/v.

44. The method of claim 7 wherein the inoculum size of the complex inoculum relative to the spent drilling mud to be treated is at least 7% w/v.

45. the method of any of claims 7-44, wherein the waste drilling mud is a waste oil-based mud or a waste water-based mud.

46. The method of claim 45, wherein the waste oil-based mud is waste oil-based mud discharged during shale gas drilling.

47. a method as claimed in any one of claims 7 to 46 for treating waste drilling mud to obtain solids.

48. Use of solids obtained after treatment of spent drilling mud according to any of claims 7 to 46 in the remediation of spent drilling mud.