Control System for Optimizing Mixing and Energy Usage for Mixing Systems

Abstract

A method and system for treating wastewater is disclosed. In one example the method comprises activating a mixing system that imparts a motive force on wastewater in a vessel, measuring at least one property of a first portion of the wastewater at a first time, measuring the at least one property of a second portion of the wastewater at a second time subsequent to the first time, calculating a difference between the at least one property measured at the first time and the at least one property measured at the second time, performing a determination of whether the difference is within a predetermined allowable range of differences, and responsive to a result of the determination, controlling a component of the mixing system.

What is claimed is: 
     
         1 .- 7 . (canceled) 
     
     
         8 . A wastewater treatment system comprising:
 a mixing system configured to impart a motive force on wastewater in a vessel;   a plurality of sensors configured to measure at least one property of the wastewater; and   a controller in communication with the plurality of sensors and a component of the mixing system, the controller configured to:   activate the mixing system;   obtain a first measured value for the at least one property at a first time using at least one sensor of the plurality of sensors subsequent to activating the mixing system;   obtain a second measured value for the at least one property at a second time subsequent to the first time using at least one sensor of the plurality of sensors;   calculate a difference between the first measured value and the second measured value;   perform a comparison between the difference and a predetermined threshold; and   responsive to a result of the comparison, control the component of the mixing system.   
     
     
         9 . The system of  claim 8 , wherein the mixing system is a hydraulic mixing system and the component is a motor driven pump positioned external to the vessel and fluidly connectable to an internal volume of the vessel via a supply conduit and a return conduit, the supply conduit fluidly connectable to a discharge side of the motor driven pump and the return conduit fluidly connectable to a suction side of the motor driven pump. 
     
     
         10 . The system of  claim 9 , wherein the hydraulic mixing system includes at least two nozzles fluidly coupled to the supply conduit and positioned within the vessel, and the motor driven pump is configured to withdraw wastewater from the vessel through the return conduit and to introduce wastewater to the vessel through the supply conduit and the at least two nozzles. 
     
     
         11 . The system of  claim 10 , wherein at least one sensor of the plurality of sensors is positioned at one of the supply conduit and the return conduit. 
     
     
         12 . The system of  claim 11 , wherein at least one sensor of the plurality of sensors is positioned within the internal volume of the vessel. 
     
     
         13 . The system of  claim 10 , wherein the at least two nozzles are configured to generate jet plumes of wastewater that sweep a bottom of the vessel and create a rotating toroidal flow pattern of the wastewater within the vessel. 
     
     
         14 . The system of  claim 9 , wherein the controller is configured to deactivate the motor driven pump responsive to the difference being within the predetermined threshold. 
     
     
         15 . The system of  claim 9 , wherein the controller is configured to one of modulate or maintain power supplied to the motor driven pump responsive to the difference exceeding the predetermined threshold. 
     
     
         16 . The system of  claim 8 , wherein the wastewater comprises activated sludge. 
     
     
         17 . The system of  claim 16 , wherein the vessel is configured as one of a digester and a sludge storage tank. 
     
     
         18 . The system of  claim 16 , wherein the at least one property is selected from the group consisting of temperature, pH, total suspended solids (TSS), dissolved oxygen (DO), and oxidation reduction potential (ORP). 
     
     
         19 . The system of  claim 16 , further including a sample loop having a portion positioned external to the vessel and fluidly connectable to an internal volume of the vessel, the sample loop configured to withdraw wastewater from the vessel and reintroduce the wastewater into the vessel. 
     
     
         20 . The system of  claim 19 , wherein at least one sensor of the plurality of sensors is positioned on the sample loop. 
     
     
         21 . The system of  claim 8 , wherein the mixing system is configured as a mechanical mixing system and the component is a motor driven mixing structure. 
     
     
         22 . The system of  claim 21 , wherein the motor driven mixing structure is one of an impeller, propeller, or plunger type linear motion device. 
     
     
         23 . The system of  claim 8 , wherein the mixing system is configured as a pneumatic mixing system and the component is a fluid control device fluidly coupled to a source of pressurized gas. 
     
     
         24 . The system of  claim 23 , wherein the pneumatic mixing system includes at least one diffuser nozzle positioned within the vessel and fluidly connectable to the source of pressurized gas. 
     
     
         25 . The system of  claim 23 , wherein the fluid control device is one of a valve and a motor driven pump.