1. PERIODIC CONTROL OF A WASTEWATER TREATMENT PROCESS TO IMPROVE PRODUCTIVITY MUHAMMAD RIZWAN AZHAR KING SAUD UNIVERSITY Saudi Arabia

2.  Introduction  Process description  Periodic control  Robustness  Conclusion Outline

3.  Usually refer to sewage treatment  Removal of containments from wastewater  Activated sludge process  Aerobic/anaerobic Introduction

4. Process Description

5.  Well mixed units  Well aerated reactor  Xi = 0  No reaction in settler  No settler dynamics  Ideal settler: Xout = 0 Process model Assumptions

6. Optimal Operating Conditions Variation of Steady State with Dilution rate; dotted: Biomass (X), dashed: Substrate (S), solid: Productivity (P r )

7. Application Concept of MPC Application Concept of MPC

8. Control Objective  Controlled Variables:  Productivity Pr=D(1-S) i.e. amount of waste water treated  Manipulated Variables:  Dilution rate D

9.  Periodic forcing the input D  Robustness in presence of Modeling error  External disturbance rejection Control objective

10.  Enhanced productivity in terms of substrate consumption  10 % increase than the maximum productivity in case steady state Controller performance

11.  Variable feed quality in WWTP  Closed loop response for -25% error in Y, 10% error µ and -10% step change in K Robustness (Tracking modeling errors)

12.  Regulatory performance  10 % increase in substrate concentration Robustness (External disturbance)

13.  10 % increase beyond the maximum productivity when periodic operation is enforced via MPC  Robust controller in presence of modeling errors and external disturbances  Less energy consumption as the fluctuation rate is kept within xx% (need to ad some numbers here)  Economically feasible (you should explain how in words) Conclusion

15. Questions