Economic performance index assessment of an industrial wastewater treatment plant in terms of the European Green Deal: effect of greenhouse gas emissions

This study aims to determine the effect of greenhouse gas (GHG) emissions on economic performance in terms of energy costs for an industrial wastewater treatment plant. Also, the mitigation of GHG emissions aimed at using process modification to obtain possible reductions in energy costs. Optimum energy consumptions were reported for the minimum GHG emission using the Data Envelopment Analysis (DEA) and Monte Carlo simulation model. In this paper, a new empirical approach has been developed depending on the GHG emissions for estimating the economic performance of the wastewater treatment plants. The results revealed that nitrous oxide (N2O) emissions led to the highest energy costs among direct emissions. In the second stage of the study, the effects of design conditions on GHG emissions and energy costs were investigated. If the aeration tank is operated at 24 h of hydraulic retention time (HRT) and 22 days of solid retention time (SRT), then, on average, 27, 27.9, and 30.7% of reduction in energy costs in terms of direct carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) emissions, respectively, is observed in the plant. These reductions corresponded to approximately 17.33 €/kWh of cost-saving in this plant.