Patents by Inventor Donald M. D. Gray

Donald M. D. Gray 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).

  • Publication number: 20130105390
    Abstract: A Class B biosolids sludge digestion process whereby feed sludge is introduced to a completely-mixed, continuously- or intermittently fed and drawn, sealed, anaerobic digester, and sludge is drawn off at a rate such that the average mean cell residence time for the sludge in the digester is greater than or equal to 10 days, and less than 15 days. The temperature of the sludge is maintained in the thermophilic range to produce treated sludge having: a volatile solids content that is at least 38% less than the volatile solids content of the feed sludge, a reduced fecal coliform content that is at least a 2 log (base 10) reduction from the feed sludge, and where there is no more than 2,000,000 most probable number/gram total solids (dry weight basis) of fecal coliform in the treated sludge.
    Type: Application
    Filed: November 2, 2011
    Publication date: May 2, 2013
    Inventors: Donald M. D. Gray, Yuyun Shang
  • Patent number: 7410583
    Abstract: A process of treating organic waste such as food wastes for anaerobic digestion including preparing a waste-slurry from organic waste such as food wastes, transferring the organic waste-slurry to a paddle pulper/finisher, processing the waste-slurry in the paddle pulper/finisher which reduces the particle size of the solids in the waste slurry and separates the waste slurry into a pulp slurry and pomace, and processing the pulp slurry in an anaerobic digester for the production of methane gas fertilizer and soil amendments. In a further process, the organic waste is slurried by dumping the organic waste in a slurry tank, adding a liquid and mechanically mixing the organic waste and liquid until consistent slurry is attained. In a still further process, the slurry from the slurry tank is processed by forming a macerator-slurry in an inline macerator unit which removes heavy solids and cuts other solids into smaller sizes which can be transferred by a slurry pump.
    Type: Grant
    Filed: August 10, 2006
    Date of Patent: August 12, 2008
    Assignee: East Bay Municipal Utility District
    Inventors: Donald M. D. Gray (Gabb), Paul J. Suto
  • Publication number: 20080035561
    Abstract: A process of treating organic waste such as food wastes for anaerobic digestion including preparing a waste-slurry from organic waste such as food wastes, transferring the organic waste-slurry to a paddle pulper/finisher, processing the waste-slurry in the paddle pulper/finisher which reduces the particle size of the solids in the waste slurry and separates the waste slurry into a pulp slurry and pomace, and processing the pulp slurry in an anaerobic digester for the production of methane gas fertilizer and soil amendments. In a further process, the organic waste is slurried by dumping the organic waste in a slurry tank, adding a liquid and mechanically mixing the organic waste and liquid until consistent slurry is attained. In a still further process, the slurry from the slurry tank is processed by forming a macerator-slurry in an inline macerator unit which removes heavy solids and cuts other solids into smaller sizes which can be transferred by a slurry pump.
    Type: Application
    Filed: August 10, 2006
    Publication date: February 14, 2008
    Applicant: East Bay Municipal Utility District
    Inventors: Donald M.D. Gray (Gabb), Paul J. Suto