Abstract: A cell for direct treatment of liquid using electrolysis uses a modular construction of electrode plates and spacer assemblies positioned between end plates. Changes in the liquid flow capacity of the cell may be made by changing the number of module housing sections and electrode plate assemblies. The design includes electrode plates that lock into a mating module housing section to resist the pressure of the fluid being treated. The design further provides for multiple fluid flow paths and for automatic cleaning of the cell using standard clean-in-place methods.

Abstract: The invention herein provides an apparatus and method of controlling an electrochemical treatment process where treatment is performed in a flow cell to ensure that a controlled dose of electrical energy or current is delivered to all volumes of the liquid being treated. In addition the invention provides for further optimization of the dose based on other factors and sensor inputs. This invention also provides a method to estimate, display and record a forecast of process efficacy such as disinfection, oxidation or other desired treatment that otherwise cannot be measured in an online manner.

Abstract: An electrolytic method and apparatus for treating liquids using a flow cell with widely spaced electrodes and polarity reversing power designed to prevent electrode fouling and provide for long continuous liquid treatment running times.

Abstract: A cell for direct treatment of liquid using electrolysis uses a modular construction of electrode plates and spacer assemblies positioned between end plates. Changes in the liquid flow capacity of the cell may be made by changing the number of module housing sections and electrode plate assemblies. The design includes electrode plates that lock into a mating module housing section to resist the pressure of the fluid being treated. The design further provides for multiple fluid flow paths and for automatic cleaning of the cell using standard clean-in-place methods.

Abstract: A method for treating a spent caustic solution having a pH greater than about 10.5 includes the steps of (a) lowering the pH of the caustic solution into the range of between about 10 to 10.5 to produce a pH-modified caustic solution; (b) oxidizing the pH-modified caustic solution until the solution to produce a non-sulfide reactive oxidized solution; and (c) lowering the pH of the oxidized solution to a pH less than 9. Methods for oxidizing inorganic substrates in aqueous solutions using an oxidizing agent such as pure oxygen, oxygen-enriched air or ozone are improved by including in the headspace above the aqueous solution a diluent gas and by recycling the oxygen with diluent gas into the reactor.

Abstract: A system and method to treat a site includes oxygenating or ozonating the site, adding nutrients, and maintaining a low bio-chemical-oxygen-demand-to-total-kjeldahl-nitrogen (BOD5:TKN) ratio. Furthermore, the system and method maintain conditions effective to permit aerobic biological deamination of organic-nitrogen compounds and nitrification of ammonia-nitrogen compounds.

Abstract: A leaching-stabilized heavy metal-contaminated matrix can be stored in a subsurface saturated zone by contacting the matrix with an amount of an agent for increasing acid-neutralization capacity sufficient to provide the stored matrix a preselected permanence level.

Abstract: A method for solidifying an oil-contaminated aqueous waste in situ or ex situ includes the step of combining the oil-contaminated waste with a clay, a cement and a sulfite salt solidification agent to form a solidified waste matrix, wherein the solidification agent undergoes hydration and cementation reactions in the waste matrix in the presence of water. Optionally, heavy metal stabilizing agents can also be combined with the waste.

Abstract: A method for treating a spent caustic solution having a pH greater than about 10.5 includes the steps of (a) lowering the pH of the caustic solution into the range of between about 10 to 10.5 to produce a pH-modified caustic solution; (b) oxidizing the pH-modified caustic solution until the solution to produce a non-sulfide reactive oxidized solution; and (c) lowering the pH of the oxidized solution to a pH less than 9.

Abstract: A method for neutralizing in situ pore water associated with a subsurface waste material body, the pore water having a pH of less than 2, the method includes the steps of adding a non-carbonate alkali to the pore water to produce a pH-modified acidic pore water having a pH between about 4 and about 5; and adding a carbonate alkali to the pH-modified pore water in an amount sufficient to raise the pore water pH to between about 6 and about 8.

Abstract: A method for treating a spent caustic solution having a pH greater than about 10.5 includes the steps of (a) lowering the pH of the caustic solution into the range of between about 10 to 10.5 to produce a pH-modified caustic solution; (b) oxidizing the pH-modified caustic solution until the solution to produce a non-sulfide reactive oxidized solution; and (c) lowering the pH of the oxidized solution to a pH less than 9.

Abstract: A method for neutralizing in situ pore water associated with a subsurface waste material body, the pore water having a pH of less than 2, the method includes the steps of adding a non-carbonate alkali to the pore water to produce a pH-modified acidic pore water having a pH between about 4 and about 5; and adding a carbonate alkali to the pH-modified pore water in an amount sufficient to raise the pore water pH to between about 6 and about 8.

Abstract: A method for treating a flue emissions stream from a high-temperature industrial process in which the stream comprises an acid gas and particulates contaminated with a hazardous metal includes the steps of dry injecting into the stream a metal stabilizing agent in an amount sufficient to reduce leaching potential of the metal under natural or induced leaching conditions and an acid gas treating agent that comprises a reactive alkaline oxide powder (−400 mesh or smaller) having a surface area of at least about 35 m2/g, (when measured by BET) in an amount sufficient to remove at least 40% of the acid gas and to act as a pH control agent for the metal stabilizing aspect of the invention.

Abstract: A cost-effective, long-term, permanent method for stabilizing chromium in a chromium-contaminated waste matrix characterized by high concentrations of alkaline material (such as lime) includes the steps of contacting a source of hexavalent chromium with a source of ferrous ions to produce ferric ions; oxidizing iron pyrite to produce ferrous sulfate and sulfuric acid; and contacting the alkaline chromium-contaminated particulate matter with the ferrous sulfate and the sulfuric acid for a time sufficient to convert ferrous sulfate into ferric sulfate and to reduce mobile hexavalent chromium to non-leachable trivalent chromium. The method is integrated in that ferrous sulfate produced by oxidizing iron pyrite serves as a source of ferrous ions in the first contacting step. Optionally, ferric ions can be generated in a side reactor and then used to produce ferrous ions. The ferrous ions can be used both to produce further ferric ions in the side reactor and to treat COPR waste.

Abstract: A leaching-stabilized heavy metal-contaminated matrix can be stored in a subsurface saturated zone by contacting the matrix with an amount of an agent for increasing acid-neutralization capacity sufficient to provide the stored matrix a preselected permanence level.

Abstract: A method for stabilizing chromium in a chromium-contaminated waste matrix characterized by high concentrations of alkaline material (such as lime) includes the steps of contacting a source of hexavalent chromium with a source of ferrous ions to produce ferric ions; oxidizing iron pyrite to produce ferrous sulfate and sulfuric acid; and contacting the alkaline chromium-contaminated particulate matter with the ferrous sulfate and the sulfuric acid for a time sufficient to convert ferrous sulfate into ferric sulfate and to reduce mobile hexavalent chromium to non-leachable trivalent chromium. The method is integrated in that ferrous sulfate produced by oxidizing iron pyrite serves as a source of ferrous ions in the first contacting step.

Abstract: A method for stabilizing arsenic in a waste matrix includes the steps of combining with the waste matrix an agent for controlling the oxidation-reduction potential of the matrix, an agent for controlling the pH of the matrix and an agent for adsorbing or coprecipitating the arsenic in the matrix.

Abstract: A cost-effective, long-term, permanent method for stabilizing chromium in a chromium-contaminated waste matrix characterized by high concentrations of alkaline material (such as lime) includes the steps of contacting a source of hexavalent chromium with a source of ferrous ions to produce ferric ions; oxidizing iron pyrite to produce ferrous sulfate and sulfuric acid; and contacting the alkaline chromium-contaminated particulate matter with the ferrous sulfate and the sulfuric acid for a time sufficient to convert ferrous sulfate into ferric sulfate and to reduce mobile hexavalent chromium to non-leachable trivalent chromium. The method is integrated in that ferrous sulfate produced by oxidizing iron pyrite serves as a source of ferrous ions in the first contacting step.

Abstract: A method for stabilizing arsenic in a waste matrix includes the steps of combining with the waste matrix an agent for controlling the oxidation-reduction potential of the matrix, an agent for controlling the pH of the matrix and an agent for adsorbing or coprecipitating the arsenic in the matrix.

Abstract: A method for stabilizing arsenic in a waste matrix includes the steps of combining with the waste matrix an agent for controlling the oxidation-reduction potential of the matrix, an agent for controlling the pH of the matrix and an agent for adsorbing or coprecipitating the arsenic in the matrix.