(4ow) Developing a Holistic Process Sustainability Measurement

The world population now exceeds 8 billion people, and the demand for goods, energy, services, and food continues to grow in parallel. As these demands are met by large-scale processes, sustainability has become vital for the long-term health of humans and the environment. To promote the most sustainable solutions in decision-making, there must be a means of comparing the sustainability of different processes. A quantitative measure of sustainability would allow for internal benchmarking, design assessment, and regulatory guidance. Frameworks such as life cycle analysis, impact assessment, and the triple bottom line provide approaches to quantify, understand, and implement sustainability concepts. Various studies have expanded on these frameworks to provide methods to quantify industrial sustainability, with strengths and weaknesses inherent to each. To determine the validity of existing metrics, the consistency of their results were compared. When utilizing existing sustainability indices, significant variation was found both in the quantification of sustainability for a single process, and in the determination of a more sustainable process when comparing two processes. These inconsistencies imply the need for additional considerations within the various indices. Sustainability metrics for the process industry have lacked an inclusion of safety, time dependence, and interrelations between sustainability pillars.

As process safety incidents are so intricately tied to economic costs, environmental impacts, and societal acceptance, this work proposes that sustainability metrics in the area should expand the triple bottom line for the basis of their methodologies to include process safety as a fourth pillar. Additionally, when a process is impacted in one of these four key aspects of sustainability, the impact on other aspects should be quantified. These interrelations have traditionally been disregarded in sustainability measurement. It has been well documented that implementation of process changes in the design stage leads to less cost and better results than the retrofitting of processes. Finally, due to the continuous impact from processes and due to the need for constant improvement to enhance sustainability, time dependence within the measurement is necessary. Therefore, an interrelated, time dependent quadruple bottom line methodology that can measure the sustainability of a process at the design stage is necessary to provide a thorough assessment of the sustainability of a process.

This led to the development of a thorough framework which expands upon established methodologies to produce a robust sustainability metric. The foundation of this framework uses an expanded triple bottom line, in which economics, environment, society, and safety are the pillars of process sustainability. For each of these pillars, categories are established for indicator selection that reflects the driving forces, pressures, states, exposures, and effects toward the process sustainability. These indicators are further analyzed using interpretive structural modeling to establish how indicators within one pillar of sustainability affect the indicators from other pillars. This framework was then utilized to produce the Holistic Process Sustainability Index, a basis for the translation from the qualitative nature of sustainability to a quantitative form. Further, with the addition of time-dependent performance factors as the basis for the indicator scaling, the index becomes a dynamic sustainability metric. Therefore, the developed framework has been applied to produce a sustainability index which provides the basis for a dynamic sustainability metric that considers the economic, environmental, societal, and safety aspects of sustainability while properly accounting for the interrelations between these different aspects. This project will be continued to add quantification to the developed sustainability index, as well as a network-based quantification for the interrelations between sustainability pillars.

Research Interests:

Sustainability of Process Systems

Energy System Safety and Sustainability

Process Systems Engineering

Machine Learning in Risk Analysis

Large-scale Testing