Abstract: A process for capturing CO2 includes contacting a CO2-containing gas with an absorption mixture optionally within a packed reactor is provided. The absorption mixture includes a liquid solution and micro-particles. The micro-particles include a support material and biocatalyst supported by the support material and are sized and provided in a concentration such that the absorption mixture flows through the packed reactor and that the micro-particles are carried with the liquid solution to promote dissolution and transformation of CO2 into bicarbonate and hydrogen ions. The absorption mixture and micro-particles may be provided in an absorption reactor so as to be pumpable. Furthermore, a process for desorbing CO2 gas from an ion-rich aqueous mixture includes providing biocatalytic micro-particles and feeding the mixture to a desorption reactor, to promote transformation of the bicarbonate and hydrogen ions into CO2 gas and water.

Abstract: A photobioreactor having an optical waveguide formed at least in part from highly scattering optically transmitting polymer. The optical waveguide has a light distributing part immersed in a container holding photoactive biological material and a light collecting part outside the container.

Abstract: Several embodiments of the invention relate generally to a system and methods for the treatment of gaseous emissions comprising methane and one or more non-methane compounds that can influence the metabolism of methane-oxidizing microorganisms. In several embodiments, there is provided a system and methods for the treatment of methane emissions through the use of methanotrophic microorganisms to generate functionally consistent and harvestable products. Certain embodiments of the invention are particularly advantageous because they reduce environmentally-destructive methane emissions and produce harvestable end-products.

Abstract: Methods and systems for removing volatile organic compounds from spent air are provided. The method can include oxidizing cumene in the presence of an oxidant to produce an oxidized product containing methanol and a spent air, separating the spent air from the oxidized product, contacting the spent air with an absorbent, an adsorbent, or a mixture thereof to remove at least a portion of any impurities in the spent air to produce a first purified air, and contacting the first purified air with a biological material to produce a treated air.

Abstract: Aspects of the invention include methods of removing carbon dioxide (CO2) from a CO2 containing gas. In some instances, the methods include contacting CO2 containing gas with a bicarbonate buffered aqueous medium under conditions sufficient to produce a bicarbonate rich product. Where desired, the resultant bicarbonate rich product or a component thereof may then be stored or further processed, e.g., combined with a divalent alkaline earth metal cation, under conditions sufficient to produce a solid carbonate composition. Aspects of the invention further include systems for practicing the methods, as well as products produced by the methods.

Abstract: There is provided a process for growing a phototrophic biomass in a reaction zone, wherein the reaction zone includes a reaction mixture that is operative for effecting photosynthesis upon exposure to photosynthetically active light radiation, wherein the reaction mixture includes phototrophic biomass that is operative for growth within the reaction zone. The process includes supplying at least a fraction of gaseous exhaust material, being discharged from an industrial process, to the reaction zone, exposing the reaction mixture to photosynthetically active light radiation and effecting growth of the phototrophic biomass in the reaction zone, wherein the effected growth includes growth effected by photosynthesis, and modulating distribution of a molar rate of supply of carbon dioxide, being exhausted from the reaction zone, as between a smokestack and at least another point of discharge.

Abstract: A biological composite and method for reducing H2S are disclosed. The biological composite for reducing H2S includes a carrier and Thermus sp. immobilized on the carrier. Therefore, if a sample containing H2S has contact with Thermus sp. or the carrier with Thermus sp. immobilized thereon, the amount of H2S can be reduced.

Abstract: A biofilter media has one or more of a set of desired physical characteristics. The set of physical characteristics includes a sphericity of 0.75 to 1, a particle size of 1 to 16 or 4 to 8 mm, a uniformity coefficient of 2 or less and a surface area of 800 to 2000 m2/m3 of media. The media is coated, supports microorganisms and is used to treat a waste gas stream.

Abstract: The present invention provides a method of treating an off-gas stream (80) comprising NH3 and H2S to provide a sulphate stream (910), the method comprising the steps of: (i) providing a first off-gas stream (80) comprising NH3, H2S, CO2 and optionally one or more of HCN, COS and CS2; (ii) passing the first off-gas stream (80) to an incinerator (300) to oxidize NH3, H2S, and optionally one or more of HCN, COS and CS2 to provide a second off-gas stream (310) comprising N2, H2O, SO2 and CO2; (iii) scrubbing the second off-gas stream (310) with a first aqueous alkaline stream (380, 876a) in a caustic scrubber (350) to separate SO2 and a part of the CO2 from the second off-gas stream to provide a spent caustic stream (360) comprising carbonate and one or both of sulphite and bisulphite and a caustic scrubber off-gas stream (370) comprising N2 and CO2; and (iv) passing the spent caustic stream (360) to an aerator (900) comprising sulphur-oxidizing bacteria in the presence of oxygen to biologically oxidize sulphite

Abstract: The present invention relates to a construct for accomplishing fixation of carbon dioxide and/or reduction of carbon dioxide emission in a heterotrophic microorganism (for example, a heterotrophic fermentation strain, such as E. coli), a vector comprising the construct, a heterotrophic microorganism (for example, a heterotrophic fermentation strain, such as E. coli) comprising the construct or being transformed with the vector, and a method for fixing carbon dioxide and/or reducing carbon dioxide emission in a heterotrophic microorganism (for example, a heterotrophic fermentation strain, such as E. coli).

Abstract: Process for the production of a biogas containing methane from an organic matter amenable to anaerobic digestion comprising feeding an anaerobic digester with the organic matter, said anaerobic digester containing a digestion medium comprising microorganisms capable of digesting said organic matter, wherein the total inorganic carbon concentration of the digestion medium is maintained above 9000 mg of equivalent CaCO3/l and the buffering capacity is maintained above 200 mmol/l by the addition of a buffering reagent comprising sodium bicarbonate to the digestion medium.

Abstract: A system for concurrently filtering particles and collecting gases. Materials are be added (e.g., via coating the ceramic substrate, use of loose powder(s), or other means) to a HEPA filter (ceramic, metal, or otherwise) to collect gases (e.g., radioactive gases such as iodine). The gases could be radioactive, hazardous, or valuable gases.

Abstract: Systems and methods are presented for the purification of a biogas. The systems comprise: a gas processor for reducing CO2, volatile organic compounds, and H2S in the biogas, the gas processor comprising a scrubber tank and a scrubber liquid; and a scrubber liquid processor in fluid connection with the gas processor for reducing the amount of absorbed gas in the scrubber liquid. The scrubber liquid processor comprises a stripper tank, and is configured to reduce or eliminate airflow through the stripper tank.

Abstract: A formulation and process for capturing CO2 use an absorption mixture containing water, biocatalysts and a carbonate compound. The process includes contacting a CO2-containing gas with the absorption mixture to enable dissolution and transformation of CO2 into bicarbonate and hydrogen ions, thereby producing a CO2-depleted gas and an ion-rich solution, followed by subjecting the ion-rich solution to desorption. The biocatalyst improves absorption of the mixture comprising carbonate compounds and the carbonate compound promotes release of the bicarbonate ions from the ion-rich solution during desorption, producing a CO2 gas stream and an ion-depleted solution.

Abstract: The present invention relates to a technique for capturing carbon dioxide and converting the carbon dioxide to carbonate minerals using a recombinant whole cell biocatalyst expressing carbonic anhydrase. More particularly, the present invention relates to a composition for capturing carbon dioxide and a method for capturing carbon dioxide using the composition, which composition comprises a whole cell of a transformant formed with a vector including a nucleic acid encoding a recombinant carbonic anhydrase; a cell lysate or its fraction of the whole cell; or a recombinant carbonic anhydrase isolated from the whole cell. Further, the present invention relates to a composition and method for converting the carbon dioxide to carbonate minerals using the carbon dioxide capturing composition.

Abstract: The present compositions and methods relate to a thermostable carbonic anhydrases, polynucleotides encoding the carbonic anhydrase, and methods of make and/or use thereof. Formulations containing the carbonic anhydrase are suitable for use in extracting carbon dioxide.

Abstract: Techniques related to enhancement of CO2 absorption use selection of an enzyme coordinated with selection of an absorption solution having a pKa to enhance or maximize the CO2 capture rate. The techniques may use various relationships between process variables such as temperature, concentration, and so on, in order to provide efficient CO2 capture.

Abstract: The present invention relates to use of heat-stable carbonic anhydrase in CO2 extraction, e.g., from flue gas, natural gas or biogas. Furthermore, the invention relates to isolated polypeptides having carbonic anhydrase activity at elevated temperatures and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides.

Abstract: A bioreactor includes a support structure and a translucent liner. A containing system of bioreactors includes a plurality of bioreactors. A contained bioreactor system includes a plurality of containing systems of interconnected bioreactors, an industrial blower, an air filter, a microbial filter, a gas delivery system, and a harvesting station. A method of reducing carbon dioxide emissions includes delivering carbon dioxide to a bioreactor where the bioreactor includes a support structure and a liner where the bioreactor includes media containing microbes. A method of harvesting microorganisms includes emptying the solution and removing a sieve from the harvesting unit.

Abstract: A high concentration H2S elimination system and a method using the same are disclosed. The system of the present invention comprises: a chemical H2S elimination module with a gas inlet, a gas outlet and a liquid outlet, wherein H2 S-containing gas is introduced into the chemical H2S elimination module; a reagent storage unit containing an oxidant; a liquid spray unit, wherein the oxidant contained in the reagent storage unit is introduced into the chemical H2S elimination module from the liquid inlet thereof through the liquid spray unit; a bio-regeneration unit comprising a microorganism to regenerate oxidant and connecting to the reagent storage unit; and a sulfur-removing module connecting to the liquid outlet of the chemical H2S elimination module.

Abstract: A formulation and process for capturing CO2 use an absorption mixture containing water, biocatalysts and an absorption compound selected from dimethylmonoethanolamine (DMMEA), diethylmonoethanolamine (DEMEA), and dimethylglycine. The process may include contacting a CO2-containing gas with the absorption mixture to enable dissolution and transformation of CO2 into bicarbonate and hydrogen ions, thereby producing a CO2-depleted gas and an ion-rich solution, followed by subjecting the ion-rich solution to desorption.

Abstract: The present invention provides a series of new and improved compounds/materials as vehicles to delivery degradative enzymes to remove/remedy environmental pollutants. The inventive material comprises a series of amide-functionalized ordered mesoporous carbon (AFOMC), which utilizes chemical conjugation techniques for the tethering of enzymes to the surface of the synthesized AFOMC. The delivery mechanism may be utilized to express a wide variety of toxin-degrading enzymes for removal/remediation of organic pollutants.

Abstract: The present invention provides a biological H2S removal system for the treatment of process gas, comprising: a housing that receives a process gas stream through a gas inlet, the housing comprising a plurality of layers through which the process gas stream flows while it is treated for H2S removal, and a gas outlet through which a treated gas stream exits; wherein air is added to the process gas stream prior to the process gas stream entering the housing.

Abstract: The present invention relates to compositions for encapsulation of biomaterials in a silica-matrix. The present invention includes a composition for formation of a silica-matrix encapsulated biomaterial. The composition includes a reactive silicon compound and a biomaterial with a catalytic activity. When encapsulated in the silica-matrix, the biomaterial at least partially retains its catalytic activity. The present invention also relates to methods of making silica-matrix encapsulated biomaterials, and to methods of using silica-matrix encapsulated biomaterials, including methods of treating water or gas using the silica-matrix encapsulated biomaterials.

Abstract: A stable continuous method for producing ethanol from the anaerobic bacterial fermentation of a gaseous substrate containing at least one reducing gas involves culturing in a fermentation bioreactor anaerobic, acetogenic bacteria in a liquid nutrient medium; supplying the gaseous substrate to the bioreactor; and manipulating the bacteria in the bioreactor by reducing the redox potential, or increasing the NAD(P)H TO NAD(P) ratio, in the fermentation broth after the bacteria achieves a steady state and stable cell concentration in the bioreactor. The free acetic acid concentration in the bioreactor is maintained at less than 5 g/L free acid. This method allows ethanol to be produced in the fermentation broth in the bioreactor at a productivity of greater than 10 g/L per day. Both ethanol and acetate are produced in a ratio of ethanol to acetate ranging from 1:1 to 20:1.

Abstract: The present invention relates to a method for controlling multi-phase chemical reactions using the architecture of surfactant foams to control mass transport of chemical reactants, catalysts, and products and the kinetics with which they react. More specifically, the invention relates to transformations that require both gaseous and liquid components with dissolved or suspended catalysts that are unstable when sheared.

Abstract: A stable continuous method for producing ethanol from the anaerobic bacterial fermentation of a gaseous substrate containing at least one reducing gas involves culturing in a fermentation bioreactor anaerobic, acetogenic bacteria in a liquid nutrient medium; supplying the gaseous substrate to the bioreactor; and manipulating the bacteria in the bioreactor by reducing the redox potential, or increasing the NAD(P)H TO NAD(P) ratio, in the fermentation broth after the bacteria achieves a steady state and stable cell concentration in the bioreactor. The free acetic acid concentration in the bioreactor is maintained at less than 5 g/L free acid. This method allows ethanol to be produced in the fermentation broth in the bioreactor at a productivity of greater than 10 g/L per day. Both ethanol and acetate are produced in a ratio of ethanol to acetate ranging from 1:1 to 20:1.

Abstract: A stable continuous method for producing ethanol from the anaerobic bacterial fermentation of a gaseous substrate containing at least one reducing gas involves culturing in a fermentation bioreactor anaerobic, acetogenic bacteria in a liquid nutrient medium; supplying the gaseous substrate to the bioreactor; and manipulating the bacteria in the bioreactor by reducing the redox potential, or increasing the NAD(P)H TO NAD(P) ratio, in the fermentation broth after the bacteria achieves a steady state and stable cell concentration in the bioreactor. The free acetic acid concentration in the bioreactor is maintained at less than 5 g/L free acid. This method allows ethanol to be produced in the fermentation broth in the bioreactor at a productivity of greater than 10 g/L per day. Both ethanol and acetate are produced in a ratio of ethanol to acetate ranging from 1:1 to 20:1.

Abstract: A Capture Carbon Storage (CCS) Process for the economical capture of carbon dioxide from coal fuel gas, and the storage of the carbon dioxide as lipid oil or the use of the environmentally begin oil for transportation. The lipid oil may be refined into gasoline, biodiesel fuel, jet fuel, ethanol, and methane which provide a renewable energy resource for the United State's future energy needs. It is a new fuel form which has been both chemically and physically altered to reduce the emissions of carbon dioxide. It is a coal cleaning/upgrading process which produces a refined fuel, Hydrogen, that may be used to produce electricity and an environmentally begin biofuel for transportation. The renewable fuel will produce no carbon foot print at the internal combustion engine's exhaust pipe. The CCS Process will produce a 100% reduction in carbon dioxide (CO2) emissions into the atmosphere and thereby, stop the Global Warming.

Abstract: A photobiorcactor (100) for use in treating polluted air and producing biomass may comprise, at least in part, a generally vertical tube or fluidic pathway (102), a generally vertical helical tube or fluidic pathway (104) having a light source (106) partially positioned within the helical fluidic pathway (104), a head cap assembly (108), and a base assembly (110). In one illustrative example, the light source (106) may be a light emitting diode (LED) or a plurality of light emitting diodes (LEDs). By one approach, a gas diffusion apparatus (112) is located at the base assembly (110) adjacent the generally vertical fluidic pathway (102).

Abstract: The present invention generally relates to immobilized biocatalysts or immobilized enzymes for use in carbon capture and sequestration technology. Thiol-ene chemistry is used to couple a biocatalyst, particularly carbonic anhydrase, to a substrate including a substrate, a solid support, a microparticle, a nanoparticle, or a combination thereof.

Abstract: A gas cracking apparatus adapted to simultaneously efficiently discharge gas heavier than air and gas lighter than air resulting from assimilations of malodorous gas and greenhouse gas. The main frame of the gas cracking apparatus includes a closed metallic circular tube or angular tube. This tube is provided at its superior portion with a superior vent and provided at its inferior portion with an inferior vent, and the tube is further provided with a gas inlet disposed between the superior vent and the inferior vent.

Abstract: Ethanol and other liquid products are produced from biomass using gasification of the biomass to produce a syngas containing CO2, CO, H2 and sulfur or sulfur compounds that passes the syngas to a fermentation step for the conversion of the CO and CO2 and H2 to ethanol. Sulfur and sulfur compounds in the syngas are used to satisfy sulfur demanded by bacteria in the fermentation step. A sulfur control additive is added to the gasification to control syngas sulfur and sulfur compounds at a desired concentration to meet bacteria sulfur demand.

Abstract: Methods, systems and apparatuses herein provide a unique and novel process to remove H2S from biogas. Methods, systems and apparatuses herein provide a unique and novel process to remove H2S from biogas with ease of operation and reduced operating and capital costs. Methods, systems and apparatuses herein provide a unique and novel process to remove H2S over CO2 from biogas.

Abstract: The present invention provides a biological H2S removal system for the treatment of process gas, comprising: a housing that receives a process gas stream through a gas inlet, the housing comprising a plurality of layers through which the process gas stream flows while it is treated for H2S removal, and a gas outlet through which a treated gas stream exits; wherein air is added to the process gas stream prior to the process gas stream entering the housing.

Abstract: A stable continuous method for producing ethanol from the anaerobic bacterial fermentation of a gaseous substrate containing at least one reducing gas involves culturing in a fermentation bioreactor anaerobic, acetogenic bacteria in a liquid nutrient medium; supplying the gaseous substrate to the bioreactor; and manipulating the bacteria in the bioreactor by reducing the redox potential, or increasing the NAD(P)H TO NAD(P) ratio, in the fermentation broth after the bacteria achieves a steady state and stable cell concentration in the bioreactor. The free acetic acid concentration in the bioreactor is maintained at less than 5 g/L free acid. This method allows ethanol to be produced in the fermentation broth in the bioreactor at a productivity of greater than 10 g/L per day. Both ethanol and acetate are produced in a ratio of ethanol to acetate ranging from 1:1 to 20:1.

Abstract: The present disclosure relates to chemically modified carbonic anhydrase polypeptides and soluble compositions, homogenous liquid formulations comprising them. The chemically modified carbonic anhydrase polypeptides have improved properties relative to the same carbonic anhydrase polypeptide that is not chemically modified including the improved properties of increased activity and/or stability in the presence of amine compounds, ammonia, or carbonate ion. The present disclosure also provides methods of preparing the chemically modified polypeptides and methods of using the chemically modified polypeptides for accelerating the absorption of carbon dioxide from a gas stream into a solution as well as for the release of the absorbed carbon dioxide for further treatment and/or sequestering.

Abstract: The present invention generally relates to improvements in enzyme immobilization, particularly for use in the field of carbon dioxide capture and sequestering. It has been discovered that the utilization of sol-gel processes to immobilize enzymes in polysilicate-polysilicone copolymer coatings and particles, and the deposition of these coatings on solid state supports or use of suspensions of these particles, provides significant benefits for use in industrial applications involving enzymatic catalysts.

Abstract: A portable odorous gas filter may provide for substantially even distribution of byproduct gas throughout a containment vessel by utilizing a diffuser plate having a plurality of holes therein. Byproduct gas from manufacturing or treatment processes may be directed into a gas plenum layer in the containment vessel through an inlet below the diffuser plate. The geometry of the diffuser plate may provide for a high-pressure differential between the plenum layer below the plate and a filter layer containing an odor-filtering media above the plate. Certain types bacteria and/or fungal strains may be added to extend the effective life of the biological media used therein.

Abstract: A system for the regeneration of carbon dioxide from a flue gas comprises an absorption vessel configured to receive a catalytically-enhanced solvent stream and a flue gas stream having CO2, the catalytically-enhanced solvent stream and the flue gas stream being contacted in the absorption vessel to provide a catalytically-enhanced CO2-rich outlet stream; a crystallizer configured to receive the catalytically-enhanced CO2-rich outlet stream from the absorption vessel and produce a two-phase outlet solvent stream having crystals; a separator configured to receive the outlet solvent stream having crystals and separate the outlet solvent stream having crystals into a catalyst solvent stream and a CO2-rich non-catalyst solvent stream; and a regenerator vessel configured to receive the CO2-rich non-catalyst solvent stream from the separator and produce a CO2 stream and a regenerator outlet solvent stream, the regenerator outlet solvent stream combined with catalyst for return to the absorption vessel as the cataly

Abstract: The present disclosure describes the efficient use of a catalyst, an enzyme for example, to provide suitable real cyclic capacity to a solvent otherwise limited by its ability to absorb and maintain a high concentration of CO2 captured from flue gas. This invention can apply to non-promoted as well as promoted solvents and to solvents with a broad range of enthalpy of reaction.

Abstract: The disclosure pertains to removal of carbon dioxide from industrial gas streams. Processes and systems are disclosed for capturing carbon dioxide from a combustion flue gas or from uncombusted natural gas by contacting with an amine blend in a first step, and an advanced solvent in a second step.

Abstract: A separation and scrubbing system for exhaust gases includes a plurality of industrial discharge outlets, a separation unit, pipelines to direct exhaust gases from the industrial discharge outlets to the separation unit and pipelines to return treated exhaust gases to stacks corresponding to the industrial discharge outlets.

Abstract: The present invention relates to biogas and biogas electric generator and a biogas electricity generation method by use microalgae for removal of carbon dioxide generated from biogas and biogas electric generator. The electric generator integrates biogas production and purification, microalga culture, electricity generation, heat recycling and others into a unit volume, and, during microalgae culturing, uses carbon dioxide contained in biogas and that produced from electricity generation as a carbon source for photosynthesis to reduce the carbon dioxide contained in the biogas and the electricity generation exhaust gas, thereby attaining the goal of zero carbon emission.

Abstract: A carbonic anhydrase bioreactor for treating a CO2-containing gas includes a reaction chamber for receiving a liquid; porous particles with carbonic anhydrase entrapped therein provided in the reaction chamber for catalyzing a reaction of CO2 into bicarbonate and hydrogen ions to obtain a treated gas and an ion-rich solution; a retention device for retaining the porous particles within the reaction chamber; a liquid inlet for providing the liquid; a gas inlet for providing the CO2-containing gas; a liquid outlet for releasing the ion-rich solution; and a gas outlet to release the treated gas. Processes are also described for treating a CO2-containing gas, where particles comprising porous material with entrapped carbonic anhydrase catalyze the reaction and the particles are retained in the reaction chamber.

Abstract: Certain embodiments of the invention involve methods and systems for preselecting, adapting, and preconditioning one or more species of photosynthetic organisms, such as algae, to specific environmental and/or operating conditions to which the photosynthetic organisms will subsequently be exposed during utilization in a photobioreactor apparatus of a gas treatment system. Also disclosed are new algal strains and cultures that can be produced by practicing the preselection, adaption, and preconditioning methods.

Abstract: The invention relates to methods of capturing carbon by microbial fermentation of a gaseous substrate comprising CO. The methods of the invention include converting CO to one or more products including alcohols and/or acids and optionally capturing CO2 to improve overall carbon capture. In certain aspects, the invention relates to processes for producing alcohols, particularly ethanol, from industrial waste streams, particularly steel mill off-gas.

Abstract: The present invention relates to use of heat-stable carbonic anhydrase in CO2 extraction, e.g., from flue gas, natural gas or biogas. Furthermore, the invention relates to isolated polypeptides having carbonic anhydrase activity at elevated temperatures and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides.

Abstract: An enzyme-catalyzed desorption process for releasing CO2 gas from an ion-rich solution containing bicarbonate ions includes providing carbonic anhydrase in the ion-rich solution such that in a desorption unit the carbonic anhydrase is allowed to flow with the ion-rich solution while promoting conversion of the bicarbonate ions into CO2 gas and generating an ion-depleted solution and releasing the CO2 gas and the ion-depleted solution from the desorption unit. A CO2 capture process includes contacting a CO2-containing gas with a solution in an absorption unit, to convert CO2 into ions; feeding an ion-rich solution to a desorption unit wherein carbonic anhydrase is present within the ion-rich solution to generate an ion-depleted solution and, preferably, recycling the ion-depleted solution. Methods of decreasing the CO2 desorption temperature in a desorption unit, decreasing the CO2 desorption reactor size, and decreasing the CO2 desorption energy input in a desorption unit, are also described.

Abstract: The present invention is directed to a composition and method to decrease the amount of particulate material in suspension, both in a liquid or in air, especially in industrial processes that generate suspended particulate material. In particular, the invention is directed to a composition and method to decrease the amount of particulate material in suspension in air or a liquid through agglomeration and subsequent biocementation, by application of an exopolysaccharide (EPS) source that can be direct or through inoculation with microorganisms that produce said EPS. This allows in a first step to settle the particulate material and subsequently the cementation of the material when there are calcium containing compounds in the particulate material that has been settled in the first step, by means of the inoculation of a second class of microorganisms that have ureolytic activity.