  In this work, a revised formulation of Chance-Constrained (CC) Model
Predictive Control (MPC) is presented. The focus of this work is on the
mathematical formulation of the revised CC-MPC, and the reason behind the need
for its revision. The revised formulation is given in the context of sewer
systems, and their weir overflow structures. A linear sewer model of the
Astlingen Benchmark sewer model is utilized to illustrate the application of
the formulation, both mathematically and performance-wise through simulations.
Based on the simulations, a comparison of performance is done between the
revised CC-MPC and a comparable deterministic MPC, with a focus on overflow
avoidance, computation time, and operational behavior. The simulations show
similar performance for overflow avoidance for both types of MPC, while the
computation time increases slightly for the CC-MPC, together with operational
behaviors getting limited
