Methods and apparatus for treating wastewater

Apparatus for oxygenating a body of wastewater containing organic solids comprising a generally enclosed oxygenating chamber having top, bottom and sidewalls and emplaceable in said body of wastewater;

• means for pumping wastewater under treatment into said chamber;
• means for creating a turbulent condition in said pumped wastewater in a mixing zone in said chamber and for contacting said turbulent wastewater with said oxygenating gas to thereby dissolve oxygen and entrain oxygenating gas in said turbulent wastewater;
• liquid accumulation means disposed within said chamber for receiving oxygenated wastewater from said mixing zone and for dissipating said turbulence to enable disentrainment and recovery within said chamber of undissolved oxygenating gas entrained in said wastewater in said mixing zone;
• and nozzle means for discharging said oxygenated wastewater into said body of wastewater at a velocity such that said body of wastewater is sufficiently stirred to maintain said organic solids suspended therein, the improvement comprising said nozzle means including an aperture defined in the lower portion of at least one of said sidewalls;
• top and bottom plate members spaced apart from one another and disposed above and below said aperture, respectively, and extending from said sidewall into said body of wastewater;
• and adjustable cover means adapted to slidably engage said top plate member and extend downwardly therefrom such that the passage between said top and bottom plate members, through which passage said discharged oxygenated wastewater may flow, is controlled in dependence upon the vertical position of said adjustable cover means.