5917 results about "Contaminated soils" patented technology

A process for in-situ remediation of contaminated soil in which at least one treating agent is introduced into the contaminated soil and transported to an underground in-situ treatment zone of the contaminated soil by a foam-based fluid.

The invention provides a system for restoring organic contaminated soil through in-situ electrical heating. The system comprises an infrastructure technology, an electronic control system, a gas treatment system, a monitoring and data acquisition system and a repairing effect comprehensive assessment system. The infrastructure technology comprises heating well and extraction well construction, ground compaction and insulating layer construction technologies; heating wells are distributed on a contaminated site according to a triangle arrangement principle and a proximity principle, and the extraction well is arranged in the geometric center of the layout of the heating well; the gas treatment system is composed of a pre-cooling adsorption sledge, an extraction sledge and a treatment sledge, and is used for completing gas extraction and treatment and achieving the tail gas discharging requirement; and the repairing effect comprehensive assessment system evaluates the temperature risingeffect of the contaminated soil in the restoring process and the treatment effect of the contaminated soil. According to the system, the technological route is complete, the soil property applicability is wide, the heating temperature can reach 500 DEG C or above, and volatile and difficult-to-volatilize organic contaminant can be treated at the same time.

Wastewater treatment systems and processes for: removal of solids, pathogens, nitrogen, and phosphorus from municipal and agricultural wastewater include nitrification of wastewater and increasing the pH of the nitrified wastewater by adding a metallic-containing salt and hydroxide to precipitate phosphorus to form a useable effluent having a specified nitrogen:phosphorus ratio that is useful as a fertilizer or spray for remediation of contaminated soils. The presence of infectious microorganism such as enteropathogenic bacteria and picarnoviruses will be reduced in the useable effluent. The precipitated phosphorus is recovered and used to form useable phosphorus products.

A stable, substantially homogeneous, solid block cleaning composition can be made for general purpose cleaning and for cleaning hard surfaces such as floors of varying surface composition. Unique solid block materials contain substantially useful concentrations of liquid acid materials, but are in the form of a stable solid. The acidic solid detergent can be dispensed using a water spray creating a concentrate which can then be diluted in proper ratio to form the use-solution. Such use-solutions may be applied to remove a variety of soils subject to acid cleaning including soils containing water hardness components, inorganic soils, and the like. The acid cleaners can be used alone or in combination with other cleaners in a cleaning protocol for a variety of hospitality, industrial or institutional cleaning locations having a broad spectrum of contaminated soil residue.

The invention discloses a passivating agent for governing heavy metal contaminated soil and a preparation and use method of the passivating agent. The passivating agent comprises, in weight percent, 30%-50% of clay minerals, 10%-20% of phosphate, 10%-15% of reducing agents, 10%-15% of sulfide and 15%-20% of alkaline substances. The preparation method includes a step: mixing the clay minerals, the phosphate, the reducing agents, the sulfide and the alkaline substances to mix to obtain the passivating agent. The use method includes the steps: firstly, crushing the heavy metal contaminated soil; secondly, adding the passivating agent into the crushed heavy metal contaminated soil; thirdly, adding water into the crushed heavy metal contaminated soil added the passivating agent to uniformly mix, maintaining the uniformly mixed soil on site, and enabling the passivating agent and heavy metal in the soil to sufficiently react. The passivating agent can effectively meet the urgent requirements of current Chinese heavy metal contaminated soil for high stability, no secondary pollution, durable and stable effect and low cost.

The invention discloses a method for treating contaminated soil by combining in-situ heat strengthening and a soil vapor extraction technology, which is characterized in that a heating well with a certain form is formed in a contaminated area, a heater part is provided in the heating well, and a sleeve pipe is installed, a catalyst is filled in the sleeve pipe for accelerating the high temperature decomposition of the pollutant into simple micromolecular substances. At least one well bore is drilled at the central contaminated area of the heating well which is arranged in the certain form to form an extraction well, a vacuum system is provided for realizing the extraction of the contaminated tail gas. the heating well provides heat to contaminated soil of the heating well and the adjacent areas through the thermal conductivity of the heater part arranged in the heating well, soil is heated, the soil pollutant is subjected to processes of evaporation, in-situ pyrolysis, oxidation, combustion, distillation and the like to form tail gas like simple micromolecular gas, water and pollutant steam, then the tail gas is extracted by the vacuum system in the extraction well, and is connected to a tail gas collection pipeline of the extraction well to send to the ground surface, the pollutant in tail gas is treated through a pollutant treatment facility which is installed on the ground surface. The method also comprises an impervious sealing plate which is arranged on the contaminated soil area ground surface for minimizing the gas exchange of the heating well, the extraction well and atmosphere, and preventing the pollutant from entering in atmosphere to form secondary pollution, and a thermal insulation layer is arranged above or below the impervious sealing plate for avoiding the dissipation of heat.

The invention relates to a method for remediation of heavy metals contaminated soil by a plant-microorganism joint direction method. The detailed steps of the method of the invention are that: firstly, resistant bacteria of plant and microorganism is sifted, so as to obtain plant and microorganism bacteria strains with heavy metal resistance; and then the seeds of the resistant plant is soaked and coated in microorganism resistant bacteria solution; finally, the seeds are planted in the soil contaminated by heavy metal, therefore the soil can be remedied. The method has the advantages of good remediation effect, low cost, easy management and operation, no secondary pollution and broad application prospect, therefore, the method is the most important development direction of soil remediation technique.

The invention discloses a stabilized curing agent for heavy metal contaminated soil or solid waste treatment and a treatment method. The stabilized curing agent comprises the following components in parts by weight: 5 to 10 parts of a magnesium-based compound, 1 to 5 parts of a sulfur-based compound and 1 to 3 parts of an activated silicon-based compound. The treatment method comprises the following steps of sampling inspection, experimental determination of adding proportion, mixing, backfill maintenance, sealing up for safekeeping and the like. The stabilized curing agent disclosed by the invention has an efficient long-term stabilizing effect on various heavy metals such as arsenic, mercury, hexavalent chromium, lead, cadmium, nickel, tin and cyanide, the repeated acid and alkali leaching experiments prove that the stabilized and cured harmful heavy metals cannot be dissolved out again, and the defects that in the traditional technology, the treatment effect and treatment agents are greatly affected by the environment, the long-term efficacy of harmless stabilization is poor, the medicament adding amount is difficult to control and the re-dissolution of harmful heavy metals is easily caused by the high alkalinity of cement solidification and the like are overcome.

The invention discloses an in situ bioremediation method for strengthening the petroleum contaminated soil by biomass which belongs to the environment restoration technique. The method utilizes the biomass added with biomass degradation fungi to promote the conversion of biomass in polluted soil. The intermediate product transformed by biomass in soil is utilized to serve as the preferential carbon source of the petroleum hydrocarbon degradation complex bacteria for promoting the biological accumulation of the petroleum hydrocarbon degradation complex bacteria; meanwhile, the imposed petroleum hydrocarbon degradation complex bacteria contains the fungus that can produce biological surface active agent efficiently, the fungus produces abundant biological surface active agent during growth to activate the petroleum hydrocarbon pollutants in polluted soil for increasing the biological utilize degree, thus promoting the biotransformation efficiency of the petroleum hydrocarbon degradation complex bacteria to pollutants. Humus of the transformation product of the biomass in the soil can also improve the granular structure of the soil, and increase the fertility of the soil, so the polluted soil can be restored. The method is simple and is easy to operate and promotion.

The invention relates to a method for repairing contaminated soil, and aims at providing a method and a device for repairing contaminated soil with persistent organic pollutants. The device comprises a separator, a material hopper, a material feeder and an indirect-heating thermal desorbing device which are connected with one another in sequence, wherein a soil emission device is connected to the bottom of the heating thermal desorbing device; a combustion system, a waste heat utilization device and an inert gas generator are respectively connected with the indirect-heating thermal desorbing device; the combustion system is connected with an outer barrel, and the inert gas generator is connected with an inner barrel; and a tail gas processing component comprises a cyclone dust extractor, a primary spray tower, a secondary regulating spray tower, a dehumidifier, a plasma reactor, an air filter, an induced draft fan and an exhaust barrel which are connected with one another in sequence. According to the method and the device for repairing contaminated soil with persistent organic pollutants disclosed by the invention, the amount of exhaust gas needing processing is less, water consumption is low, the persistent organic pollutants are thoroughly removed, the operation cost is reduced by 30%-60%, and the contaminated soil with persistent organic pollutants can be economically and effectively processed.

The invention provides a system for restoring organic contaminated soil by forced ventilation and spiral stirring thermal desorption, which comprises an air preheating system, a spiral stirring thermal desorption system, a tail gas treatment system and a control system, wherein the air preheating system consists of a blower and an air heater, the spiral stirring thermal desorption system consists of a spiral stirring thermal desorption device and a draft fan, the tail gas treatment system consists of a cyclone dust collector, a dehumidifier and an absorption tower, and the control system can realize the effective control of the rotation speed of a spiral stirrer, the air preheating temperature and the soil heating temperature. The system can be used for restoring soil contaminated by volatile/semi-volatile organic matters.

The invention discloses an ectopic classification leaching repair complete process of arsenic and heavy metal contaminated soil. The repair process comprises the following steps: the contaminated soil is magnetically separated to extract and recover target metals; a nonmagnetic component is divided into three grades by a vibrating screen after being primarily crushed; stones and boulders are flushed by clear water to directly serve as building materials; thick and fine soil particles obtained through screening respectively enter second-grade leaching mixing equipment for washing; the solid-liquid separation is performed for mud generated by washing through a two-stage hydraulic cyclone device; leaching waste liquid is purified and regenerated for recycling; sludge is added with such repair materials as curing/stabilizing agents for safety treatment after being dehydrated; and after the treatment, the soil particles can be backfilled, or can serve as roadbeds, building materials and the like. Based on the characteristic of large difference of arsenic and heavy metal contents in soils with different particle sizes, the soil leaching treatment according to the particle size is performed, so that the process has such advantages as low repair cost, high treatment efficiency and saving of energy consumption, provides a new method for soil heavy metal pollution abatement, and is broad in application prospect.

The invention discloses a heavy metal contaminated soil conditioner and a plant and chemistry combined remediation method. The heavy metal contaminated soil conditioner is a mixture of red mud and slaked lime. In the invention, the plant and chemistry combined remediation method is used, the pH of the soil is regulated by a chemical method, and heavy metals in the soil are absorbed by planting energy crops, hyperaccumulative plants and the like, thereby improving the soil properties, gradually reducing the content of heavy metals in the soil, finally achieving the purpose of soil remediation, improving the plant remediation efficiency, and being favorable to large-scale commercial application.

The invention relates to a method for remediating cadmium contaminated soil of a vegetable field in situ by compounding bio-charcoal and an organic fertilizer. The method comprises the following steps of: applying a passivation material obtained by compounding the bio-charcoal and the organic fertilizer in a mass ratio of 1:1 to a surface layer of soil of a cadmium contaminated vegetable field, fully and uniformly mixing the passivation material and the soil in a plowing layer with the thickness of 0 to 20cm, judging the contamination level of the soil according to environmental quality standard for soils GB15618-1995, and ensuring that the application rate of the passivation material is not less than 0.5 percent of the weight of dry soil, namely 750kg/mu when the cadmium concentration of the soil is 1.0 to 2.9mg/kg. The invention has the advantages that: raw materials of the passivation material are wide in source and low in cost, the application method is simple and has a remarkable effect of remediating the cadmium in the soil in a passivation way, and the risk of secondary contamination is avoided; and the bio-charcoal is applied into the soil, so the passivation material has the effects of reducing the discharge of greenhouse gas of farmland ecosystems, increasing the content of organic carbon of the soil, improving soil structures and the like, and has huge popularization and application value.

The invention provides an electric complex-strengthening repairing method and device of heavy metal-organic co-contaminated soil. The method provided by the invention comprises the following steps of: filling contaminated soil into an electric repairing device, and then adding an oxidant into a cathode electrolyte and an anode electrolyte or directly spraying the oxidant on the contaminated soil, wherein the oxidant comprises hydrogen peroxide, pypocholoride and persulfate; applying a direct-current electric field on a cathode and an anode, wherein the strength of the electric field is 0.5-2 V/cm; and controlling the pH values of the cathode electrolyte and the anode electrolyte to be 3-11. By selecting the suitable for oxidant and controlling the pH value of the electrolyte, the migration of the heavy metal can be effectively increased and the removing efficiency is improved; and meanwhile, the oxidant is used for effectively degrading organic pollutants when the pollutants are migrated, thereby relieving the post-treatment and simultaneously removing the heavy metal and the organic pollutants.

The invention discloses a thermal desorption method for contaminated soil, which comprises the following steps of: performing thermal desorption on the contaminated soil at the temperature of between 400 and 650 DEG C; incinerating gaseous contaminant-containing flue gas which is discharged by the thermal desorption step at the temperature of between 750 and 1,200DEG C; and performing afterheat utilization and tail gas treatment on the incinerated flue gas. When the thermal desorption method is used for treating the contaminated soil, the destruction and removal efficiency for the organic contaminants in the contaminated soil is over 99 percent, the tail gas meets the emission standard, and the possible secondary pollution in the process of treating the contaminated soil is stopped, so that the effective innocent treatment is realized and the original reutilization property of the soil is maintained.

A stabilizer suitable for heavy metal contaminated soil and an application method thereof belong to the technical field of contaminated soil remediation treatment. The invention is characterized in that: the soil stabilizer comprises the following components by mass: 5%-8% of heavy metal chelants, 10%-20% of gelled materials, 50%-65% of clay mineral, 10%-15% of alkaline excitants; the gelled material, clay mineral and alkaline excitant are mixed and grinded to obtain a Blaine specific surface area of 5000-8000 cm2/g; the mixture is sieved by a 200-mesh sieve, and the water content is less than 3%; the heavy metal chelant is prepared into a solution by water with a mass percent of the chelant being 20%-40%. The stabilizer and soil are uniformly mixed, and conserved for above 5 days. The main components of the stabilizer are mostly natural materials; after the stabilizer is used, heavy metal contaminants in soil can be rapidly and effectively stabilized, and the toxicity of the contaminants is reduced. The materials used are economical and easily available, and do not cause secondary contamination, and the stabilizer is a rapid and high-efficient stabilizer for heavy metal contaminated soil.

The invention discloses a composite chemical leaching method for remediation of heavy metal contaminated soil. The method includes: leaching heavy metal contaminated soil 1-3 times by a composite leacheate prepared from ferric chloride and an organic acid, then further conducting leaching 1-3 time with distilled water, and finally separating the leacheate from soil. The method provided in the invention has the advantages of good treatment effect, short leaching time, no secondary pollution, simple operation, relative low cost, a highest cadmium removal rate of over 80%, and a highest lead removal rate of over 55%. The iron-containing compound involved in the invention is used as an improver of paddy soil. The residue of ferric chloride has a positive effect on chemical properties of soil, and cannot destroy the soil structure. The used organic acid is easy to degrade, and the degradation product can become nutrients of plants and is environment-friendly. The final leaching by water can reduce the content of metal ions and the leacheate residue in the remedied soil, thus being in favor of later crop tilling.

The invention discloses an electrodynamic method for removing fluorine contaminant in soil, which is as follows: an anion-exchange membrane is arranged between the anode and the contaminated soil to prevent the H+ generated by the anode from entering the electrolyzer so as to avoid the increase of the acidity of the contaminated soil; sodium acetate solution is put in an anode chamber to be used as electrolyte, deionized water is put in a cathode chamber to be used as electrolyte, and the liquid levels of the anode chamber and the cathode chamber are maintained to be parallel; in the rehabilitating process, the electrolytes circulate constantly to be stirred evenly so as to bring away the H2 and O2 which are generated by the anode and the cathode; the sodium acetate solution added in the anode chamber supplies OH- which neutralizes the H+ generated by the anode, and the surplus OH- and the OH- generated by the cathode promote the adsorbed fluorine in the soil to be desorbed to be free fluorinions; and the fluoride in the soil is removed through the electrodynamic approaches of electromigration, electroosmosis and the like. The method can effectively promote the adsorbed fluoride to be desorbed from the surface of the contaminated soil particles, remarkably improves the fluorine contaminant removal efficiency, reduces overpotential and saves energy consumption, and after the soil is rehabilitated, the pH value of the soil is basically maintained at the original state.

The invention relates to a direct pyrolysis device. In the direct pyrolysis device, a heating part comprises a primary heating part and a secondary heating part; both a feed part and an auxiliary part are connected with the primary heat part; a dedusting part comprises a primary dedusting part and a secondary dedusting part; an emission part comprises a gas emission device and a soil emission device; the primary heating part is orderly connected with the primary dedusting part, the secondary heating part, a quenching part, the secondary dedusting part, a washing part and the gas emission device; the primary heating part is also connected with the soil emission device; all the components are respectively connected with a monitoring part; the washing part is a washing tower; and the tail end of the washing tower is connected with the gas emission device. The invention has the advantages of high handling capacity, low energy consumption, low handling cost and the like, maintains the advantages of physico-chemical properties of soil and the like, and can effectively separate organic substances from contaminated soil and dispose the contaminated soil.

The invention discloses a heavy metal stabilizing agent and a method for treating heavy metal contaminated soil by using the heavy metal stabilizing agent. The heavy metal stabilizing agent is prepared from the following raw materials in percentage by weight: 40 to 50 percent of phosphate, 20 to 25 percent of bentonite, 25 to 30 percent of fluor apatite and 4 to 6 percent of sodium chloride/potassium chloride. When the heavy metal stabilizing agent is used for treating the contaminated soil, the heavy metal stabilizing agent and water are mixed together to form a suspension, then the suspension is added into the heavy metal contaminated soil, and the suspension and the heavy metal contaminated soil are fully mixed. The heavy metal stabilizing agent has high stability for treating soil, and the technical problem that the conventional curing agent and curing method cause reverse dissolution easily is solved.