Of the three spheres of sustainability – economic development, environmental stewardship and societal equity, only the first two are quantifiable based on process variables. While economic criteria (e.g. payback period and net present worth) are well established, environmental objectives are still novel and there is no general consensus on aggregation methods for calculating environmental impact. Many contributing factors have been identified for environmental impacts: impact on humans, ecosystem (terrestrial and aquatic), local/global temperatures (global warming and ozone depletion), photochemical oxidation, acid rain and eutrophication. Several aggregation methods for the environmental indicator have also been discussed. From a literature review of previous studies that employed environmental indices, most papers used an aggregate environmental index as the objective, and in some papers, the analysis is coupled with an economic objective. Hence, feasibility and usefulness of process optimization for more than two economic and environmental objectives is studied. A VOC (volatile organic component) recovery system is optimized for both economic and environmental objectives using the elitist non-dominated sorting genetic algorithm. The contributing factors to the environmental impacts are optimized individually or grouped into a few indices where appropriate. The Pareto-optimal solutions obtained elucidate the trade-offs present, and the decision maker would be better equipped in choosing the best solution. Net flow method is used to identify the preferred Pareto-optimal solution based on the preferences declared by the decision maker. Insights gained from considering a number of environmental objectives for process optimization are highlighted.