Technoeconomic Optimization of Emerging Technologies for Regulatory Analysis

Evaluating sustainable technologies during the regulatory design process requires tools for rapidly assessing the cost and performance of compliance technologies that leverage process integration or are still in the development phase. This work demonstrates the use of gray-box optimization to facilitate process assessment during regulatory design, using the recent Effluent Limitation Guidelines regulating the discharge of flue gas desulfurization wastewater as a case study. We build computationally lean meta-models of an emerging ammonium-bicarbonate forward osmosis (NH 4 HCO 3 FO) technology that is heavily integrated with heat sources at the power plant. We then compare the capital and operational costs of an NH 4 HCO 3 FO and crystallization treatment train against that of mechanical vapor recompression and crystallization, the “Best Available Technology” for zero liquid discharge and the basis for EPA’s benefit cost analysis during the regulatory process. We estimate that the NH 4 HCO 3 FO treatment train would reduce the cost of zero liquid discharge by $0.30–$1.20/m 3 and would have reduced the cost for a stricter evaporative standard by $20–$70 million nationwide. Finally, we discuss opportunities and challenges associated with deploying gray-box optimization techniques for the rapid assessment of emerging technologies in policy analysis.