Sustainability life cycle boundaries

The problem is the boundary limit of the techno-economical assessment, for example, which costs are effectively considered (see also later discussion regarding life-cycle assessment). This is a moving boundary that should be determined from the best-available-technology (BAT) and the related legislative limits on emissions. However, a more advanced concept is to consider the chemical process as a component of the environment and set the local legislative limits on emissions to values that do not decrease the biodiversity in the specific area where the process is localized. There are many problems in implementing this concept which introduces the idea that emissions from chemical production (and in general from all industrial and human activities) should have a value connected to the capacity of the environment to sustain the life (biodiversity). 

LCSA extends the environmental boundaries of traditional LCA in an attempt to incorporate the concept of sustainable development. It is defined as a method of addressing environmental, economic, and social sustainabiHty of a product system over its life cycle, indicated through the measurement of either positive or negative impacts [3]. LCA has been implemented through an integration of E-LCA, hfe cycle costing (LCC), and social life cycle assessment (S-LCA) [3]. Brief definitions of E-LCA, LCC, and S-LCA are described in Table 14.1. 

The stages of the bioelectricity hfe cycle include (1) raw material process and production (2) raw material transportation (3) R D (4) plant construction (5) bioelectricity generation and (6) bioelectricity transmission. These stages are similar for conventional electricity. Fig. 14.2 iUustrates six stages of bioelectricity s life cycle and its system boundaries for the three piUars of sustainability, which is similar for conventional electricity (reference system). 

Manufacturing processes for sustainability can be optimized in the context of life cycle analysis (Shoimard and Hiew 2000). It involves definition of the process boundaries and quantifiable sustainability impacts in the form of established metrics, incorporated into process design and optimization. It has been applied to determining waste treatment options, abatement of pollution, and designing the optimal recipe of solvents. Impact indices, such as ozone depletion potential to human toxicity and eco-toxicity, developed by the EPA, can be used. This method has been applied in a methyl ethyl ketone production plant to determine the effect of recycling on the enviromnent (Shonnard and Hiew 2000). 

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