Life cycle assessment of the City of Atlanta, Georgia’s centralized water system

Life cycle assessment of low impact development technologies combined with conventional centralized water systems for the City of Atlanta, Georgia

“…Most stormwater runoff is collected through separate pipelines within the city [23]. The design life of bioretention areas was assumed as 30-years [22,24].…”

“…The impact of native plants on the environment was assumed to be negligible because neither herbicides, pesticides, nor fertilizer are used for growing plants within the ponding area. The direct emissions of water pollutants into the environment were calculated according to the removal efficiency of the bioretention areas (Table 1), and the water pollutant concentrations estimated for the city's stormwater runoff [23]. The removal efficiency of heavy metals was assumed equivalent to that of suspended solids, 80%, since heavy metals in stormwater runoff are mostly adsorbed by the soil [39].…”

“…Therefore, we used the freshwater ecosystem impact (FEI) indicator to evaluate the impact of freshwater consumption on the regional water ecosystem. FEI is the product of the freshwater volume consumed in a process and the water resource stress, which is defined as the ratio of water withdrawal to water availability (WTA) [49,50]; however, due to similarities in measurement, we used the water supply stress index (WaSSI) instead of the WTA [23]. Accordingly, the FEI can vary with respect to the river basin's water stress.…”

LCA Methodology for the Quantification of the Carbon Footprint of the Integrated Urban Water System

“…As the main driver of the carbon footprint increase in the urban water cycle is related to energy efficiency, this variability may depend on several aspects of the energy consumption (such as high level of leakages, the need for significant water treatment, and inefficient plants and pumping stations); in addition, the energy mix adopted at the national level (including sources such as coal, nuclear fission, natural gas, or renewable sources) may produce a different environmental impact of supplied energy. For example, in Barjoveanu et al [11], the results have pointed out that the higher impacts are mainly due to the energetic effort needed for water supply abstraction and the fairly high water losses in the distribution system; for Jeong et al [16], the electricity consumption is mainly due to water transport and treatment. In this case study, rather than water treatment, the greater energy consumption is to be attributed to the pumping stations and to the significant water volumes that need to be pumped to compensate for water losses.…”

“…Other studies focused on urban drainage systems [13,14] and treatment plants [14,15]. More complete studies, like Jeong et al [16], proposed an exhaustive analysis on environmental and human health impacts related to the integrated urban water cycle. It includes a comprehensive analysis of different impacts, providing lumped information on the whole system.…”