Method for the treatment of wastewater

Claim 1

A method for the continuous treatment of wastewater, comprising the steps of: providing a treatment tank having: a horizontally disposed baffle extending longitudinally of and across said tank and separating said tank into an upper biological treatment zone and a vertically adjacent lower settling zone extending across the full tank width; partition means extending along the length of the tank transverse to said physical means and dividing said biological treatment zone into a central bay and a left and a right secondary bay, each of said secondary bays being horizontally adjacent said central bay; each of said primary and secondary bays including a plurality of biological contactors partially submerged in said wastewater; said contactors being disposed parallel to the direction of wastewater flow through said primary and secondary bays; an inlet at one end of said tank; and an outlet at the opposite end of said tank; introducing a first stream of wastewater into said left secondary bay at said inlet end of said tank; introducing a second stream of wastewater into said right secondary bay at said inlet end of said tank; creating a parallel flow of said first and second streams through the left and right secondary bays in the same direction away from said inlet end; rotating said biological contactors in said left and right secondary bays to biologically treat said first and second streams of wastewater while flowing away from said inlet end; horizontally directing said first and second streams into said primary bay to combine said streams; creating a flow of said combined first and second streams through said primary bay in a direction countercurrent to the flow of said first and second streams through said left and right secondary bays and toward said inlet end; rotating said biological contactors in said primary bay to biologically treat said combined first and second streams; vertically directing said combined first and second streams from said primary bay to said lower settling zone at said inlet end; creating a flow of said combined first and second streams through said lower settling zone in a direction countercurrent to the flow of said combined first and second streams in said primary bay and away from said inlet end; and removing said combined first and second streams from said lower settling zone at said outlet end.

Claim 2

A method for the continuous treatment of wastewater, comprising the steps of: providing a treatment tank having: a horizontally disposed baffle extending longitudinally of and across said tank and separating said tank into an upper biological treatment zone and a vertically adjacent lower settling zone extending across the full tank width; partition means extending along the length of the tank transverse to said physical means and dividing said biological treatment zone into a central bay and a left and a right secondary bay, each of said secondary bays being horizontally adjacent said central bay; each of said primary and secondary bays including a plurality of biological contactors partially submerged in said wastewater; said contactors being disposed parallel to the direction of wastewater flow through said primary and secondary bays; an inlet at one end of said tank; and an outlet at the opposite end of said tank; introducing a first stream of wastewater into said left secondary bay at said inlet end of said tank; introducing a second stream of wastewater into said right secondary bay at said inlet end of said tank; creating a parallel flow of said first and second streams through the left and right secondary bays in the same direction away from said inlet end; rotating said biological contactors in said left and right secondary bays to biologically treat said first and second streams of wastewater while flowing away from said inlet end; horizontally directing said first and second streams into said primary bay to combine said streams; creating a flow of said combined first and second streams through said primary bay in a direction countercurrent to the flow of said first and second streams through said left and right secondary bays and toward said inlet end; rotating said biological contactors in said primary bay to biologically treat said combined first and second streams; vertically directing said combined first and second streams from said primary bay to said lower settling zone at said inlet end; creating a flow of said combined first and second streams through said lower settling zone in a direction countercurrent to the flow of said combined first and second streams in said primary bay and away from said inlet end; and removing said combined first and second streams from said lower settling zone at said outlet end.