Patents Assigned to Hazen and Sawyer, P.C.
  • Patent number: 5385673
    Abstract: A method of treating wastewater biosolids by destruction of pathogens and indicator organisms to meet or exceed USEPA Process to Further Reduce Pathogens standards. The method first depresses the pH to below 5, followed by pH increase to 12 or higher, causing an exothermic reaction and heat of hydration. The mixture is placed within a confined volume to maintain the temperature at or above 55.degree. C. for at least two hours. The mixture can be dewatered for a higher percent solid characteristic. The material is then tested and if test results indicate, the material is approved by the Environmental Protection Agency for human contact. The biosolid materials are suitable for general nutrient values with minimal regulatory restriction and other beneficial uses.
    Type: Grant
    Filed: September 8, 1992
    Date of Patent: January 31, 1995
    Assignee: Hazen and Sawyer, P.C.
    Inventor: Robert E. Fergen