Patents by Inventor Ajit K Chowdhury

Ajit K Chowdhury has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 8961751
    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.
    Type: Grant
    Filed: September 30, 2010
    Date of Patent: February 24, 2015
    Assignee: Biolonix, Inc.
    Inventors: James A. Tretheway, Myron F. Miller, Karl W. Marschke, Brian R. Hale, Ajit K. Chowdhury, Jeremy J. Vogel
  • Publication number: 20110108438
    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.
    Type: Application
    Filed: September 30, 2010
    Publication date: May 12, 2011
    Inventors: James A. Tretheway, Brian R. Hale, Dennis E. Bahr, Ajit K. Chowdhury, Jeremy J. Vogel, Karl W. Marschke
  • Publication number: 20110079520
    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.
    Type: Application
    Filed: September 30, 2010
    Publication date: April 7, 2011
    Inventors: James A. Tretheway, Brian R. Hale, Ajit K. Chowdhury, Jeremy J. Vogel, Dennis E. Bahr, Myron F. Miller, Karl W. Marschke
  • Publication number: 20110079510
    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.
    Type: Application
    Filed: September 30, 2010
    Publication date: April 7, 2011
    Inventors: James A. Tretheway, Myron F. Miller, Karl W. Marschke, Brian R. Hale, Ajit K. Chowdhury, Jeremy J. Vogel
  • Patent number: 7560034
    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.
    Type: Grant
    Filed: February 24, 2006
    Date of Patent: July 14, 2009
    Assignee: RMT, Inc.
    Inventor: Ajit K. Chowdhury
  • Patent number: 7497948
    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.
    Type: Grant
    Filed: October 25, 2005
    Date of Patent: March 3, 2009
    Assignee: RMT, Inc.
    Inventors: Ajit K. Chowdhury, Jack W. Anderson
  • Patent number: 7374367
    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.
    Type: Grant
    Filed: July 1, 2003
    Date of Patent: May 20, 2008
    Assignee: RMT, Inc.
    Inventor: Ajit K. Chowdhury
  • Patent number: 7351191
    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.
    Type: Grant
    Filed: September 2, 2005
    Date of Patent: April 1, 2008
    Assignee: RMT, Inc
    Inventors: Ajit K. Chowdhury, Jeff C. Macri, Kevin L. Baker, Gregory J. Graf
  • Patent number: 7005076
    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.
    Type: Grant
    Filed: June 6, 2003
    Date of Patent: February 28, 2006
    Assignee: RMT, Inc.
    Inventors: Ajit K. Chowdhury, Sarah Wilk
  • Patent number: 6949197
    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.
    Type: Grant
    Filed: June 6, 2003
    Date of Patent: September 27, 2005
    Assignee: RMT, Inc.
    Inventors: Ajit K. Chowdhury, Terry Vandenbush
  • Publication number: 20040245185
    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.
    Type: Application
    Filed: June 6, 2003
    Publication date: December 9, 2004
    Inventors: Ajit K. Chowdhury, Terry Vandenbush
  • Publication number: 20040245188
    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.
    Type: Application
    Filed: June 6, 2003
    Publication date: December 9, 2004
    Inventors: Ajit K. Chowdhury, Sarah Wilk
  • Publication number: 20040247506
    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.
    Type: Application
    Filed: June 6, 2003
    Publication date: December 9, 2004
    Inventors: Ajit K. Chowdhury, Lane D. Tickanen, Michael Warner
  • Publication number: 20040126189
    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.
    Type: Application
    Filed: July 22, 2003
    Publication date: July 1, 2004
    Inventor: Ajit K. Chowdhury
  • Publication number: 20040024282
    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.
    Type: Application
    Filed: July 1, 2003
    Publication date: February 5, 2004
    Inventor: Ajit K. Chowdhury
  • Patent number: 6607474
    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.
    Type: Grant
    Filed: June 27, 2001
    Date of Patent: August 19, 2003
    Assignee: RMT, Inc.
    Inventor: Ajit K. Chowdhury
  • Patent number: 6543964
    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.
    Type: Grant
    Filed: December 29, 2000
    Date of Patent: April 8, 2003
    Assignee: RMT, Inc.
    Inventors: Ajit K Chowdhury, Lane D Tickanen
  • Publication number: 20020049361
    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.
    Type: Application
    Filed: June 27, 2001
    Publication date: April 25, 2002
    Inventor: Ajit K. Chowdhury
  • Publication number: 20010048852
    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.
    Type: Application
    Filed: December 29, 2000
    Publication date: December 6, 2001
    Inventors: Ajit K. Chowdhury, Lane D. Tickanen
  • Patent number: 6254312
    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.
    Type: Grant
    Filed: June 18, 1998
    Date of Patent: July 3, 2001
    Assignee: RMT, Inc.
    Inventors: Ajit K Chowdhury, Lane D Tickanen