Methodology for environmental risk assessment of industrial nonroutine releases

While increasing social concern and strict legislation have resulted in expanding the conventional design objectives of profitability to include environmental impact and operability aspects, traditional practices regarding environmental risk assessment (ERA) have mainly focused on providing qualitative guidelines to evaluate the likelihood and consequence of undesired events to the environment. By linking process reliability considerations to environmental impact analysis within a process optimization framework, this work presents a systematic method for the quantification and at source minimization of combined adverse environmental effects of routine (i.e., waste water effluent streams) and nonroutine releases (i.e., leaks, emissions from equipment breakdown). Trade-offs are explored regarding cost and routine/nonroutine environmental impact objectives, while opportunities for effective maintenance strategies are identified. The steps of the theoretical analysis and the potential of the proposed methodology are illustrated with two example problems, a simplified chemical reaction-separation scheme and a methane chlorination process.