83 results about "Iron bacteria" patented technology

The invention relates to three compound stabilizer reagents which can effectively protect various water pipelines, water containers and the relevant equipment of the water conveyance system from biodeterioration or scaling and the treatment method and the utilization of the biodeterioration. Particularly, by utilizing the three compound stabilizer reagents acting on the water conveyance system in different period respectively, the addition dosage and the time can change according to different water quality, different microorganism pollution degree and different water treatment demand, wherein each compound stabilizer reagent main component has different sterilization mechanisms and the emphases of the reagent is also different, so that serious corrosion caused by the drug resistance of the bacteria can be solved and the sulfate reducing bacteria, the saprophyte, the iron bacteria, the nitrite bacteria, the ammonium bacteria and algae in the water conveyance system can be completely killed. The compound stabilizer reagents is suitable for the control of pipeline scaling and the pipe wall biodeterioration of the oil field water injection system, the circulating water system and the central air-conditioning cooling water system.

The invention discloses an oil field sewage bactericide and a preparation method thereof, belonging to the technical field of chemical agents for oil fields and preparation thereof. The oil field sewage bactericide is prepared by mixing the following components in percentage by mass: 10-15% of nano titanium dioxide powder, 0.5-2% of crosslinking agent, 5-10% of surfactant, 5-10% of oxidizer and the balance of water. The bactericide can be deposited on pipe walls, bent angles and other parts along with a liquid flow; a main agent can be slowly diluted out, has persistent chemical action and causes no corrosion to pipelines; the comprehensive sterilizing rate of the bactericide with respect to sulfate reducing bacteria, saprophytic bacteria and iron bacteria can be still up to 90% or above 18 days after filling; and the filling period of the chemical agent is 15-25 days which is 10-15 times longer in comparison with a common chemical agent, thereby greatly relieving the operation intensity and lowering the cost.

The invention relates to a bactericidal and algaecidal composition for an intermediate water system, a prepration method and an application thereof, wherein, the composition comprises the following components of bisquaternary ammonium salt, modified quatemary ammonium salt, penetrating agent, synergist and water, wherein, the water is used as a solvent. The bactericidal and algaecidal compositioncan effectively prevent the propagation of bacteria and algae and other phenomena in cooling water. The bactericidal and algaecidal composition simultaneously has the roles of stripping slime, removing odor and the like. The result shows that the composition has significant bactericidal and algaecidal effects, the bactericidal rate of heterotrophic bacteria, iron bacteria, ammonifying bacteria andsulfate-reducing bacteria can be more than 95%, the bactericidal effect is excellent, the composition is applicable to water quality with complicated change (high high-temperature and float indicators, high ammonia nitrogen indicators, high oil indicators and high organic phosphorus indicators), a wide range of fluctuations and the like, the dose is small, and the excellent bactericidal and algaecidal requirements can be achieved by only 50-100mg / l. In addition, the product has small toxicity and easy degradation. Therefor, the composition has good economic benefits, environmental protectionbenefits and social benefits for enterprises.

Described is a method of water treatment including the steps of: a) Stripping water or dissolved gas by an inert gas b) Subjecting water to oxidation treatment to precipitate metals; and c) Removing precipitates from water. Oxidation treatment is a multi-stage oxidation treatment including the stages of: (1) contacting water with oxidant under pressure to precipitate metals from water; and (2) catalytic oxidation of water with oxidant, oxidation being catalysed by a catalyst, such as a zeolite catalyst, in a bed reactor or filter. Inert gas stripping is aimed at preventing growth of iron bacteria in the treatment system. Pressurised oxidation reduces the amount of oxidant injection required for catalytic oxidation. The method is particularly suited to removal of contaminants such as iron, manganese and arsenic from ground water.

The invention relates to an oligomeric quaternary ammonium salt bactericide and a preparation method thereof. Ester p-toluenesulfonate-based gemini quaternary ammonium salt, guanidine hydrochloride and sodium alkoxide are added into solvent, stirred and heated to 120 DEG C to 180 DEG C, heating is stopped after 10 to 48 hours of reaction, so that a crude product is obtained, and after post-treatment, the oligomeric quaternary ammonium salt bactericide is obtained; and the substance amount ratio of the ester p-toluenesulfonate-based gemini quaternary ammonium salt, the guanidine hydrochloride and the sodium alkoxide is (0.008 to 0.040):0.008:0.008. The gemini quaternary ammonium salt is introduced to a plurality of active sites, eight active sites are contained in the structure of the oligomeric quaternary ammonium salt bactericide, the oligomeric quaternary ammonium salt bactericide can show good water solubility and surface activity in aqueous solution, and an important role is played in the process of oligomeric quaternary ammonium salt preparation. A bacteria killing test on three types of bacteria, i.e. sulfate reducing bacteria, iron bacteria and saprophytic bacteria, indicates that the oligomeric quaternary ammonium salt bactericide has a good bactericidal effect.

The invention relates to the technical field of chemical engineering, and relates to a bactericide for petrochemical circulating water, and in particular relates to a compound bactericide which can be used for remarkably reducing corrosion of a petrochemical circulating water pipeline and reproduction of phycomycetes. The bactericide mainly consists of organic alkali, pypocholoride, a surfactant, alkyl benzyl ammonium chloride and water which are uniformly mixed. The bactericide in the proportion has a remarkably inhibiting effect and sterilizing property on microorganisms such as sulfate reducting bacteria and iron bacteria of a using system, can be used for remarkably reducing the general amount of bacteria in the circulating water, that is to say, prolonging the service life of equipment, improving the repeating utilization factor of the cooling water and reducing the consumption of water resources.

The invention relates to a compound bactericide for an oilfield flooding system, belonging to the technical field of oilfield sewage treatment. The compound bactericide for an oilfield flooding system is characterized by comprising the following components in percentage by weight: 70-80% of 45-55% (mass percent) benzalkonium chloride water solution, 10-20% of 25-35% (mass percent) cetylpyridinium bromide ethanol solution and 10-15% of 18-22% (mass percent) tetrachloroisophthalonitrile xylene solution. The compound bactericide for an oilfield flooding system has very high bactericidal effect, can effectively remove sulphate reducing bacteria, iron bacteria and saprophytic bacteria in the sewage and prevent the bacteria from corroding and blocking pipeline equipment, and has the advantages of simple components, convenient preparation, quick and efficient action, low cost, high bactericidal rate, low consumption, small side effect and the like.

The invention discloses corrosion and scale inhibition biodegradable bactericide used for water treatment. The bactericide is prepared from 5-30% of hexadecyl dimethyl (2-sulphurous) ethyl ammonium, 5-20% of acrylic acid-allyloxy polyether-acrylate copolymers, 5-30% of polyquaternium, 2-25% of polyaspartic acid and 25-50% of water. The 28-day degradation rate of the bactericide reaches 90%, and the bactericide has a good bactericidal effect on microorganism soil bacteria, sulfate reducting bacteria, iron bacteria and heterotrophic bacteria, has the corrosion and scale inhibition functions, has a good dispersion effect on calcium carbonate scale and is environment-friendly bactericide used for water treatment.

The invention provides an application of a pyridines compound shown as a general formula (I) in the specification, to preparation of a bactericide, wherein R is H or a methyl, and n is 1,2 or 3. The invention also relates to an application of the composition which takes the compound as a main effective ingredient to preparation of the bactericide. The bactericide has efficient action on killing harmful bacteria, such as sulfate reducing bacteria, saprophyte and iron bacteria in an oil field water system, industrial cycling water and urban pipe network sewage systems to reach a bacteria amount control standard in oil filed injected water and cycling water..

The invention provides a compound bactericide used in oilfield flooding, relating to oilfield water treatment. The bactericide comprises the following components by weight percent: 60-70% of deionized water, 2-5% of surfactant, 25-30% of organic aldehyde and 5-10% of cyanogen-containing compound. The bactericide used in oilfield flooding can act under the conditions of high hardness, high alkalinity and high temperature, has stable chemical properties, has terrific treatment effects on iron bacteria, also has a stronger effect of stripping slime layers, has the advantages of high efficiency, low toxicity, difficulty in being affected by change of the pH value, good compatibility with other water treatment agents, lower amount of admixture and the like and can be widely used in the fields of oilfield flooding and sewage treatment in the oilfield industry.

The invention relates to an ecological combined device for treating sewage with high ammonia-nitrogen content. The ecological combined device comprises a multifunctional regulation pool, a deodorizing device, an internal-electrolysis anaerobic / anoxic organism iron-carbon reaction pool, a flexible biomembrane contact oxidation filter pool, an air blower room, a sedimentation tank and constructed wetlands. According to the ecological combined device disclosed by the invention, organic pollutants, nitrogen / phosphorus pollutants and animal / vegetable oils and fats are efficiently removed from wastewater through integrating hydrolysis, microelectrolysis and the biochemical reaction of iron bacteria, anaerobic bacteria, facultative bacteria and the like and combining a physical / chemical adsorptive precipitation-percolation process and a plant absorption and transformation process. The ecological combined device can be widely applied to a high-concentration organic wastewater and reclaimed water recycling system and a regenerated water recycling landscape water system, and has the characteristics of stability, reliability, low investment, low operating energy consumption, low operating cost, easiness in maintenance and management, and the like.

The invention provides a biological heavy metal contaminated soil remediation agent as well as a preparation method and application thereof, and belongs to the technical field of heavy metal contaminated soil remediation. The preparation method comprises the steps of inoculating a template material with good stability and dispersibility and iron bacteria into a 9K culture medium, loading the surface and pores of the template material with the iron bacteria so as to add various active groups to the material and enhance the adsorption effect of the template material on metal ions, oxidizing ferrous ions into ferric ions under the action of the iron bacteria at the same time, and after reacting with ammonia water, calcining at high temperature to form the biological heavy metal contaminated soil remediation agent. The remediation agent has the adsorption performance of iron bacteria and iron oxide at the same time and has good dispersing performance. The adopted raw materials are environmentally friendly, the preparation process of the remediation agent is simple, the adsorption efficiency is high, and the effect of remediating soil or water contaminated by heavy metal arsenic and antimony for a long time can be achieved.

This invention relates to a water soluble paint, in particular a kind of room temperature film-forming antirust paint which can restrain and kill iron bacteria. This antirust paint is composed by there kinds of antibiosis combination: 0.5 to 1 share of poly- hexa- methylguanidine macromolecule poly-guanidine type antibiosis agent, 1 to 2 shares of zirconium phosphate, silver-carrying, nanometer powder, antibiosis agent, 3 to 4 shares of nanometer zinc oxide powder antibiosis agent; group stuff are water-solubility resin latices and room temperature film-forming agent and dope accessory ingredient of in common use; take water as diluter.

The invention belongs to the technical field of soil remediation, and particularly relates to a complex microbial agent for efficiently converting heavy metal chromium in soil as well as a preparation method and application thereof. The complex microbial agent is obtained by mixing and carrying out enrichment culture on the following two florae: a flora A consisting of bacillus, pediococcus acidilactici, clostridium coriolis, actinobacillus succinogenes and bacillus aceticus; a flora B consisting of acidophilic iron bacteria, thiobacillus ferrooxidans, acid-thiobacillus thiooxidans, sulfur-oxidizing acid-thiobacillus thiooxidans, sulfur-oxidizing bacteria and acidophilic thiobacillus ferrooxidans. After the complex microbial agent is used for treating the chromium-contaminated soil, the chromium removal rate can reach 91% or above. The complex microbial agent is formed by culturing and mixing a plurality of strains, and the strains have a good synergistic effect and do not generate antagonism; after compounding, the adaptability to heavy metals can be improved, so that the survival and removal effects of the soil in heavy metal contaminated soil are improved. The microbial agent is simple in preparation and application method, short in culture period and treatment period and low in cost, prevents secondary pollution, and has a wide application prospect.

The invention provides preparation of a water injection clay swelling prevention agent with antibacterial and anti-scale functions and discloses a cationic surface active agent which is synthesized autonomously, has relatively good functions of preventing clay swelling or clay granule migration, and in addition has excellent anti-erosion resistance and a good antibacterial capability; a phosphino-maleic acid-acrylic copolymer anti-scale agent which is synthesized autonomously has a good calcium scale inhibition capability and is capable of retarding blocking of scale; after the phosphino-maleic acid-acrylic copolymer anti-scale agent is compounded with urea, dodecyl dimethyl benzyl ammonium chloride, ammonium chloride and potassium chloride, a clay swelling prevention agent with good antibacterial and anti-scale functions can be prepared. The water injection clay swelling prevention agent provided by the invention has a good property of inhibiting clay hydration swelling, a good anti-erosion capability, excellent capabilities of preventing calcium sulfate and calcium carbonate scale, is capable of effectively killing sulfate reducing bacteria, saprophytic bacteria and iron bacteria, in addition is low in cost, has a creative demonstration function for developing water injection clay swelling prevention agents with multiple functions in one agent, and has wide application prospects.

The invention particularly relates to a method for repairing a polluted water body by using an immobilized composite microorganism technology. The method comprises: mixing microorganisms separated from a to-be-repaired polluted water body and having repairing function and functional strains, immobilizing, pouring the immobilized composite microorganisms into the to-be-repaired water body, and repairing, wherein the functional strains comprise: 10-40 parts of photosynthetic bacteria, 20-50 parts of yeast, 10-30 parts of Bacillus megaterium, 20-35 parts of lactic acid bacteria, and 10-20 parts of iron bacteria. According to the present invention, the functional strains separated and preserved by the company and in situ microorganisms in the corresponding polluted water source are compounded,and the polluted water body is repaired after the immobilizing, such that the repairing efficiency is high.

The invention provides fungicide for a seawater circulating water system and a preparation method thereof. The fungicide is prepared from the following components in percentage by weight: 5 to 20 percent of dibromo-2-cyanoacetamide, 10 to 25 percent of polyhexamethylene guanidine, 5 to 15 percent of polixetonium chloride, 20 to 50 percent of quaternary phosphonium salt, 5 to 20 percent of isothiazolinone and 5 to 10 percent of polyethylene glycol 400. The fungicide provided by the invention can sufficiently express a synergistic effect of all the components and can be used for effectively inhibiting and killing shells, heterotrophic bacteria, fungi, iron bacteria, algae and the like.

The invention discloses a microbial water purifying agent for snakehead culture water and a preparation method thereof. The preparation method comprises the following steps: adding 20-40 parts by weight of surface-modified C8 and C18 alkyl-chain magnetic silicon balls into 200-400 parts by weight of water; adding 80-100 parts by weight of microbial reagent, including 60-80 parts of Synechococcus, 60-80 parts of Oscillatoria, 10-30 parts of Nitrosococcus, 10-30 parts of Nitrosolobus, 10-20 parts of iron bacteria, 10-20 parts of Leptothrix, 1-5 parts of Thiothrix, 1-5 parts of Vitreoscilla, 30-70 parts of paramecium, 30-70 parts of infusorian, 30-50 parts of Tetraselmis and 30-50 parts of blue algae; and adding 50-90 parts by weight of beef extract peptone agar culture medium, and culturing. The microbial water purifying agent can be added into a snakehead culture tank to achieve the goal of purifying culture tank water.

Provided is a flora for degrading sludge and removing foul smell and a usage method thereof. The compound flora includes, by weight, 10%-12% of thiobacillus denitrificans, 1.3%-5% of salt resistant bacteria, 2.6%-3.9% of nitrous acid leafy bacteria, 2.1%-3% of filamentous sulfur bacteria, 3.2%-4.0% of bifidobacterium, 1.3%-2.6% of nitrogen-fixing bacteria, 2.6%-3.2% of filamentous bacteria, 2.1%-2.6% of rhizobia, 2.6%-4.0% of iron bacteria, 1.3%-2.6% of cyanobacteria, 5.3%-6.6% of thermophilic bacteria, 5.3%-7.4% of halophilic bacteria, 0.5%-2.6% of sulfur producing bacteria, 1.3%-2.6% of oilphilic bacteria, 10.6%-21% of lactobacillus, 5.3%-9.2% of saccharomycetes, 7.9%-15.9% of bacillus, 2.6%-5.3% of actinomycetes, 1.3%-2.6% of photosynthetic bacteria and 3.2%-4.8% of high-temperature aerobic bacteria.

The invention relates to salt-resistant polyacrylamide for oil displacement. The salt-resistant polyacrylamide is prepared from the following components in parts by weight: 770-840 parts of deionizedwater, 150-260 parts of acrylamide, 10-30 parts of an anionic monomer and 5-40 parts of functional monomer microemulsion. The invention further relates to a preparation method for the salt-resistant polyacrylamide for oil displacement. According to the salt-resistant polyacrylamide and the preparation method thereof, the functional monomer is introduced into a polymerization formula, so that sulfate-reducing bacteria, iron bacteria, saprophytic bacteria and the like in sewage can be inhibited, the viscosity retention rate of the salt-resistant polyacrylamide for oil displacment in the sewage for 180 days is greater than 90%, and therefore the viscosity retention rate of the polyacrylamide in the sewage is greatly increased; and meanwhile, the functional monomer adopts a microemulsion preparation mode, blocks in a molecular structure of a product are more uniform, the solubility of the product is greatly improved, and therefore the problem that conventional polyacrylamide is dissolved slowly in the sewage or in high-salinity brine can be solved.

The invention discloses an oil field sewage bactericide and a preparation method thereof, belonging to the technical field of chemical agents for oil fields and preparation thereof. The oil field sewage bactericide is prepared by mixing the following components in percentage by mass: 10-15% of nano titanium dioxide powder, 0.5-2% of crosslinking agent, 5-10% of surfactant, 5-10% of oxidizer and the balance of water. The bactericide can be deposited on pipe walls, bent angles and other parts along with a liquid flow; a main agent can be slowly diluted out, has persistent chemical action and causes no corrosion to pipelines; the comprehensive sterilizing rate of the bactericide with respect to sulfate reducing bacteria, saprophytic bacteria and iron bacteria can be still up to 90% or above 18 days after filling; and the filling period of the chemical agent is 15-25 days which is 10-15 times longer in comparison with a common chemical agent, thereby greatly relieving the operation intensity and lowering the cost.

The invention discloses a double quaternary ammonium salt type gas field reinjection water bactericide and a bactericide composition comprising the bactericide. Compared with a traditional bactericide 1227, the double quaternary ammonium salt provided by the invention has higher positive charge density, and the capacity of absorbing negatively charged bacterial cell surfaces is improved. Therefore, the bactericide provided by the invention has relatively high antibacterial activity. Also, the bactericide has the advantages of long effect duration and low foam. The double-long-chain quaternary ammonium salt has one hydrophilic group and two hydrophobic groups, such that higher capacity for reducing surface tension is provided, and water solubility can be improved. Under a condition of relatively high water hardness, good solubility and stability are shown. With the gas field reinjection water bactericide composition, a bacteria test is carried out according to an extinction dilution method represented by SY / T0532-93, and bactericidal experiments are carried out aiming at sulfate-reducing bacteria (SRB), iron bacteria (FB) and saprophytes (TGB). As a result, an effective bactericidal concentration is 20-30ppm, and a bactericidal rate reaches 99.9% and higher, such that reinjection requirements are satisfied.

The invention discloses a preparation method of a slaughter house sewage disinfectant which belongs to the field of disinfectants. A finished product of the chicken house disinfectant is prepared by employing a chlorine dioxide aqueous agent, potassium ferrate and pure water as raw materials and blending the raw materials at a certain temperature. The preparation method is advantaged by being less in required devices, simple in production technology and low in cost. Production and utilization of the finished product is harmless to human body. The slaughter house sewage disinfectant has good killing effects on endospores, viruses, heterotrophic bacteria, iron bacteria, sulfate reducting bacteria, funguses and the like, and has multiple functions such as algae removing, mud peeling, anti-corrosion, anti-mildew, freshness-retaining, deodorization, chlorination, bleaching and the like. The finished product can fully satisfy a requirement of killing various bacteria and viruses and removing algae in sewage generated in a slaughter house, has a good disinfection effect and is low in cost, but the compound chicken house disinfectant is slightly poor in stability so that the compound chicken house disinfectant needs to instantly use after preparation.

The invention provides a method for processing and recycling oil-field exploitation waste water, making air oxidation and catalytic oxidation on the waste water, making catalytic oxidation and air oxidation on volatile phenol, sulfide, Fe2+, etc, on more moderate reaction conditions, and modifying them; filtering out deposits, removing oxygen from the filtrate by low-temperature desorption and obtaining oxygen free water, and finally killing sulfate reducing bacterium, saprophyte and iron bacterium by UV sterilizing processing. And the test shows that it can process polymer-containing waste water in oil field to make the waste water directly reach water reinjection requirements, having low operating expenses.

The invention provides an efficient compound sterilization corrosion inhibitor capable of inhibiting and decomposing a biological film and for a water system. The efficient compound sterilization corrosion inhibitor is prepared from the following components in percentage by weight: 0.003 to 0.01 percent of quaternary phosphonium salt, glutaraldehyde and / or cecropin, 0.0001 to 0.005 percent of D-amino acid and the balance of water, wherein the D-amino acid can be used for inhibiting and decomposing the biological film attached on a metal surface and the biological film is converted into a floating sate from a fixation state and microorganisms can be easily killed through fungicide, so that the sterilization effect of the fungicide can be remarkably enhanced and the corrosion caused by the microorganisms is alleviated to the great extent; all the components of the compound sterilization corrosion inhibitor have a synergistic effect and have an extremely excellent sterilization corrosioninhibition effect; the killing rates on sulfate-reducing bacteria, iron bacteria and saprophytic bacteria are greater than or equal to 99 percent and the corrosion inhibition rate is greater than or equal to 80 percent; the disadvantages of traditional fungicide of large dosage, high cost, great toxicity and heavy environment burdens are overcome.

The invention belongs to the technical field of oil and gas field development, and particularly relates to a corrosion and scale inhibition bactericide and application thereof. Effective components ofthe corrosion and scale inhibition bactericide consist of a betaine ampholytic surfactant, hexadecyl dimethyl (2-sulphurous acid) ethylammonium and a lignin derivative, wherein the weight ratio of the betaine ampholytic surfactant to the hexadecyl dimethyl (2-sulphurous acid) ethylammonium to the lignin derivative is (2-10): (1-5): (1-50). Based on a total inventive concept, the invention furtherprovides a preparation method and application of the corrosion and scale inhibition bactericide. The corrosion and scale inhibitor can effectively kill reducing bacteria, iron bacteria and saprophytic bacteria in oilfield reinjection water, and has excellent corrosion and scale inhibition performance. When the preparation combination is added into a reinjection water system, the water quality requirement of oilfield reinjection water can be met, and the crude oil water drive recovery ratio can be increased, and the corrosion and scale inhibition bactericide is economical and efficient.

The invention relates to a pipeline paint. The pipeline paint comprises modified phenol formaldehyde resin, water-based inorganic aluminum sol resin, polyethersulfone resin, acetic acid-tertiary carbonic acid emulsion, alkyd emulsion, polysorbate, ethylene glycol dimethyl ester, sodium alginate, calcium carbonate crystal whisker, aluminum tripolyphosphate, colloid potassium silicate, ferrotitanium powder, sodium hexametaphosphate, metanitrophenol, dodecyl mercaptan, glycerol, a diluter and a solvent. The pipeline paint has the advantages of favorable adhesive force, low shedding tendency and long service life, can effectively prevent natural corrosion and microbial corrosion of iron bacteria to the pipeline, and has favorable acid corrosion resistance.

The invention discloses a composite sterilization corrosion inhibitor for an oil field and a preparation method of the composite sterilization corrosion inhibitor and aims to solve the problem that a composite sterilization corrosion inhibitor which has a good sterilization effect and a corrosion inhibition effect as well is not available for an oil field. The product comprises the following raw materials in parts by weight: 18-35% of an intermediate, 10-20% of glutaraldehyde, 2-8% of thiourea, 5-10% of an alcohol solvent and the balance of water. The product is prepared by introducing naphthenic acid imidazoline acetate on the basis of an oleic acid imidazoline quaternary ammonium salt, and due to introduction of imidazoline of a cyclic hydrocarbon structure, not only are sterilization and corrosion inhibition coordinated, but also the compatibility and the permeability of a chemical upon raw oil can be improved, and together with the thiourea, the glutaraldehyde and the like, the composite sterilization corrosion inhibitor has good effects of sterilization and corrosion inhibition, has good specificity for oil-containing sewage of the oil field, has remarkable killing and inhibition functions on sulfate reducing bacteria, iron bacteria, saprophytic bacteria and the like in the oil-containing sewage, and has a good inhibition function on corrosion caused by sulfides, carbon dioxide, dissolved oxygen, saline ions and the like in the oil-containing sewage.

The invention discloses a composite bactericide for oilfield reverse flooding, and a preparation method thereof, and belongs to the technical field of oilfield exploitation and sterilization. The composite bactericide is prepared from 30-40 wt% of 50% N-alkyl bisquaternary ammonium salt and 60-70 wt% of 70% dodecyl dimethyl benzyl ammonium chloride. The 50% N-alkyl bisquaternary ammonium salt andthe 70% dodecyl dimethyl benzyl ammonium chloride are sequentially added into a stirring tank, and are stirred for 30 min after the complete addition of the raw materials in order to obtain the composite bactericide for oilfield reverse flooding. The composite bactericide has the advantages of strong bactericidal effect, effectiveness in removal of sulfate reducing bacteria, iron bacteria and saprophytic bacteria in flooded water, simple preparation method, low production cost, low use amount and high sterilization rate.