A robust optimization model for designing a wastewater treatment network under uncertainty: Multi-objective approach.

•Developing an optimization model for a wastewater treatment network.•Developing a robust flexible chance-constrained model to deal with uncertain parameters.•Extending the mathematical model to a bi-objective model to reduce CO2 emissions.•Proposing a new iterative approach to find the efficient solutions.•Demonstrating the application of the proposed model in Alberta, Canada.