Displaced treatment is a treatment that is reduced, replaced, or substituted as a consequence of a change in supply or demand for the material for treatment. This concept is particularly relevant in consequential Life Cycle Assessment, where the focus is on understanding how changes in one part of a system affect activities elsewhere in the economy.
When a by-product or waste material from one activity becomes available for use in another activity, it can displace the need for treatment services that would otherwise have been required for similar materials. The displacement occurs because the incoming material substitutes for materials that were previously being treated, thereby reducing the treatment capacity needed for those original materials. Conversely, when demand for treatment of a particular material increases, it may displace treatment of other materials by consuming available treatment capacity.
Understanding displaced treatment is essential for accurate consequential LCA modelling, as it helps identify the indirect effects of changes in material flows. When a material for treatment is generated or eliminated, the consequential approach requires consideration of which treatment activities will actually change as a result. These changes may occur through direct substitution, where one material replaces another in a treatment process, or through market adjustments, where shifts in supply and demand alter the allocation of treatment capacity across different material streams.
The concept is closely related to system expansion and substitution modelling, where the environmental consequences of by-products and waste materials are assessed not merely by their direct treatment requirements, but by the broader changes they induce in treatment systems. This approach ensures that the assessment captures the full consequences of decisions affecting material flows, including both the avoided and the additional treatment activities that result from those decisions.
