A sustainability-based socio-technical-environmental project selection algorithm

摘要

Abstract Including environmental and health impacts in project option selection is important to serve humanity and reduce the adverse effects of development. An algorithm is introduced here that includes lifecycle costs, avoided losses, users’ willingness to pay and value per statistical life (VSL), and both environmental and health impacts. The algorithm is entitled the Socio-Technical-Environmental Project Selection (STEPS) algorithm and incorporates social and health aspects through the willingness to pay, technical aspects through the engineering design, and economic aspects through the lifecycle costs. The algorithm consists of estimating the various quantities needed, such as lifecycle costs, benefits (avoided mortality and infrastructure losses), willingness to pay, and the Environmental Protection Agency’s Maximum Contaminant Level (EPA-MCL). These values are plotted with the environmental and health impacts on the horizontal axis and the Net Cost (equal to the lifecycle cost minus the benefits) on the vertical axis. The most balanced option is the one that plots closest to the origin of the plot. The new algorithm is demonstrated on project selection for the elimination of riverbank erosion using recycled concrete aggregate (RCA) as riprap. RCA uses previously used crushed concrete from demolition as aggregate for any beneficial purpose such as aggregate for new concrete or riprap, as in this case. The disadvantage of RCA, however, is that harmful chemicals leach out when exposed to water. Four options were considered, namely (1) do nothing, (2) use RCA as a riverbank erosion countermeasure, (3) use RCA with a leachate treatment system, and (4) use rock riprap instead of RCA. It was found that the proposed STEPS algorithm leads to the selection of Option 3 with RCA riprap and leachate treatment. Selecting by cost alone would have led to Option 2, which also happens to result in a violation of the EPA-MCL for the arsenic leachate. In addition, Option 4 would have been selected without considering RCA or the problem with landfills reaching capacity with the addition of crushed concrete. The STEPS algorithm, therefore, resulted in the most sustainable solution considering both the lifecycle cost and health and environmental impacts.