The concept of sustainability is often associated with the statement: “… development that meets the needs and aspirations of the present without compromising the ability to meet those of the future …”[1] More practically, to simultaneously achieve the triple bottom lines of sustainability, it is a need to: i) to create more value, wealth, and profits in the economically viable dimension, ii) to provide cleaner products with less raw resource consumption and waste generation in the environmentally compatible dimension, and iii) to have more socially benign products, services, and impacts in socially responsible dimension.[2]

Industrial sustainability is a vital issue in pursuing the long-term development of a given industry, which is closely related to the material efficiency of an industrial zone, region, or beyond. Despite comprehensive concerns and considerable efforts toward sustainability, many industrial activities have profound impacts not only on people's quality of life, but also to the global environment and economy. Industrial sustainability is, therefore, a very important issue in which the improvement of the efficiency of material and energy usage becomes beneficial to the sustainable development of an industrial system. Such improvements include the reduction of raw material consumption and/or waste generation, while simultaneously maintaining previous production levels.

Industrial sustainability demands industries to significantly improve energy efficiency, minimize waste, and improve product quality, all of which are great challenges to the metal finishing industry. In the U.S. alone, there are over 10,000 independent electroplating operations for the automotive, electronics, aerospace, and general manufacturing industries, with additional metal finishing operations as parts of larger manufacturing facilities. These plants consume an excessive amount of energy and generate a huge amount of waste in the form of wastewater, sludge, and spent solutions, which usually contain over 100 chemical, metal, and non-metal contaminants which are regulated by the EPA.[3] The continuous generation of these wastes has and will continue to severely threaten both public health and the environment. As such, the need for the reduction of contaminated waste streams from plating plants is critical and imperative.

This paper will introduce the general mathematical framework of a sustainability decision-analysis methodology, which will be developed based on the existing Ecological Input-Output Flow Analysis (EIOFA) method.[4] The methodology can be used to help decision makers in the metal plating industry reach appropriate decisions on the future sustainable development of their industrial system, of any complexity. Using this methodology, one is capable of determining methods for reducing the toxicity of the contaminated material waste streams, improving the raw material usage efficiency, thus improving the industry's environmental, economic, and societal performance while integrating the process design and operation with management decisions. While an assessment of material efficiency for a known system is relatively easy, developing decision-making policies for future system sustainability considerations is always a big challenge. This is particularly true when such decision-making activities heavily involve system impacts from future economics, environment, and society, where the available information is almost always uncertain, incomplete, and imprecise. Although a large number of case studies on system sustainability assessments have been conducted, a development of systematic decision-analysis methodologies for the industrial sustainability is still needed.

Various case studies have demonstrated the capabilities of the proposed optimization models. Admittedly, industrial sustainability is a complex task, which needs tremendous efforts from multidisciplinary institutes. This work is trying to seek industrial sustainability opportunities from the system-engineering point of view. Improved energy efficiency issues will be combined with the improved material efficiency to form a general mathematical framework based on our current research.

[1] World Commission on Environment and Development, Our Common Future, Oxford University Press, Oxford, 1987. [2] Odum, H. T., Environmental accounting: Emergy and Environmental Decision Making, New York: John Wiley & Sons, 1996. [3] PRC Environmental Management, Inc., Hazardous Waste Reduction in the Metal Finishing Industry, Noyes Publ., Park Ridge, NJ, 1989. [4] Bailey, R. Input-Output Modeling of Material Flows in Industry. Doctoral Dissertation, G. W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA. 2000.