An improved life cycle impact assessment (LCIA) approach for assessing aquatic eco-toxic impact of brine disposal from seawater desalination plants

摘要

Most Life Cycle Assessment (LCA) studies did not quantify the aquatic eco-toxic potential (aquatic ETP) of the brine disposal mainly due to the limitation of current life cycle impact assessment (LCIA) approaches. The purpose of this study is to develop an improved approach for assessing the aquatic ETP of brine disposal from seawater desalination plants. The proposed approach, named group-by-group approach, calculates the average aquatic ETP as the sum of the impacts generated by acknowledged groups of influential chemicals. This approach firstly identifies the influential chemicals. According to the chemical property and the impact pathway to the aquatic ecosystem, the important chemicals are then categorized into groups under three categories. Depending on the characteristics of the defined groups, different strategies are applied to determine the impact of each group. The group-by-group approach takes the merits of two most commonly-used approaches, chemical specific approach and whole effluent approach. The results from the case study indicated that this approach reduces the reliance on the comprehensive chemical composition analysis and temporal ecotoxicology test of the complex desalination brine. It also provides a more comprehensive coverage, not only considering the impact of organic chemicals and metals, but also including the contribution of inorganic chemicals.