Orbital wastewater treatment system and associated method of operating an orbital wastewater treatment system

A method for operating an orbital wastewater treatment system including a tank assembly, at least one impeller in said tank assembly for moving mixed liquor about said tank assembly, said method comprising:

• flowing mixed liquor or wastewater into a treatment pool in said tank assembly;
• determining a rate of inflow of said mixed liquor or wastewater into said tank assembly;
• rotating said impeller within said pool to move said mixed liquor or wastewater about said tank assembly;
• determining a first rate of energy usage from (a) the determined rate of inflow and (b) energy usage by said impeller;
• adjusting a rate of rotation of said impeller and a degree of submergence of said impeller in said pool;
• after adjusting the rate of rotation of said impeller and the degree of submergence of said impeller in said pool, determining a second rate of energy usage from the determined rate of inflow and the energy usage by said impeller;
• comparing said second rate of energy usage with said first rate of energy usage to determine a net change in energy consumption;
• and
• subsequently adjusting the rate of rotation of said impeller and the degree of submergence of said impeller in said pool in accordance with the net change in energy consumption.

An orbital wastewater treatment system comprising:

• a tank assembly;
• at least one impeller in said tank assembly for moving mixed liquor about said tank assembly;
• a movable weir operatively mounted to said tank assembly;
• a mixed-liquor infeed conduit extending to said tank assembly;
• a flow meter in operative relationship to said conduit;
• a variable speed motor operatively connected to said impeller;
• an actuator operatively connected to said weir;
• and
• a control unit operatively connected to said flow meter, said actuator and said motor,
• said control unit being configured to calculate a rate of energy usage from impeller activity and a rate of mixed-liquor or wastewater infeed as measured or sensed by said flow meter,
• said control unit being further configured to operate said actuator and said motor to adjust a rate of rotation of said impeller and a degree of submergence of said impeller in a wastewater pool in said tank assembly to reduce a rat of energy usage.