Simultaneous Optimization of Plants for Nitrogen and Phosphorus Removal, Reuse, Energy and Emissions through a Real Time Operations Controller in Middle-East-Asia and Chesapeake Bay Region of US

The challenges of simultaneous optimization of a whole wastewater treatment plant for permit compliance, energy, chemical use and GHG emissions across primary, secondary and tertiary systems, together with solids handling, are significant. A real time whole plant simulator for process control and optimization (Aquifas+) has been developed with a complete GHG module. The simulator uses an enhanced version of IWA ASM2d model for mixed liquor and biofilm. For simulating nitrous oxide and nitric oxide emissions, it includes a four step denitrification process; it includes a two step nitrification process with ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB); it includes an additional three step denitrification process for certain types of AOB. The simulator incorporates mathematical algorithms for inverting a matrix of 150+ equations at higher speeds and accuracy required for real time operations control and optimization as compared to plant design. Its application requires calibration that is conducted over a six month to a one year period. The simulator connects and manages data from SCADA, laboratory and plant inspection systems which it stores efficiently in a database together with the data from simulations. It provides feedback to the operators to help them optimize simultaneously for a combination for compliance, greenhouse gas emissions, energy and chemical use. It does so by generating multiple combinations of feasible operating scenarios at intervals that are customized to the flow, HRT and needs of each plant. The paper includes results of application to plants in North America, Middle-East and Asia.