Patent ID: 6086765
Filing Date: 2000-07-11
Classification: C02F,Y02A,Y02W,Y10S

Abstract:
A method for treating a wastewater influent comprising:providing an uppermost aerobic zone, an anoxic zone; and, a lowermost anaerobic zone arranged in a vertically disposed relationship in a substantially closed cylindrical vessel having a bottom approximating an inverted cone; wherein said anaerobic zone is adjacent to said anoxic zone, and said anoxic zone is adjacent to said aerobic zone;feeding said influent at about the interface of said anaerobic zone and anoxic zone sufficient to contribute to causing an upflow through said anoxic zone and said aerobic zone;feeding air at about the lowest most portion of said aerobic zone;inducing a substantially horizontal rotational motion component to said upflow;enabling solids from said upflow to settle into said anaerobic zone;withdrawing an overflow stream from about an uppermost point of said aerobic zone;providing a screening zone;feeding said overflow stream into said screening zone;withdrawing an effluent from said screening zone;withdrawing a first substantially solids fraction from said screening zone;passing at least a portion of said first substantially solids fraction to a sludge storage zone and/or passing at least a portion of said first substantially solids fraction to at about the interface of said anaerobic zone and anoxic zone;withdrawing a second substantially solids fraction from about a lowest most portion of said anaerobic zone; and,passing at least a portion of said second substantially solids fraction to a sludge storage zone and/or passing at least a portion of said second substantially solids fraction to at about the interface of said anaerobic zone and anoxic zone.