The improvement options identified for the North Shore City Council (NSCC) collection system included parallel sewer augmentations, new flow path alternatives, pump station upgrades, inflow and infiltration (I/I) reduction, flow control storage facilities and wastewater treatment plant (WWTP) upgrades.

The optimization was performed using genetic algorithm-based software Optimizer WCS and the results were compared to the baseline solution from a previous optimization study that was completed using linear programming optimization software, SEWCOM (also known as Seeker).  The results from each optimization method are compared on an apples-to-apples basis in the table below.  Allowing for final engineering adjustments of the optimized solution, a conservative estimate for the cost savings achieved in this study is $75 M / 25%.