Eco-efficiency assessment of domestic wastewater treatment technologies used in Chile

Abstract

Wastewater treatment plants have been the widest technologies used to mitigate the environmental impacts of domestic wastewater. Currently, Chile has the largest coverage of wastewater sanitation (99.85%) of Latin American, through the use of conventional technologies, mainly active sludge and aerated lagoons and also unconventional technologies such as biofilter, vermi-biofilter, among others. Although all technologies allow fulfilling with discharge standards, there are differences in the flows of matter and energy associated with the kind of technology used, which implies the generation of different environmental impacts. The objective of this research was to evaluate the eco-efficiency of different domestic wastewater treatment technologies used in Chile, based on the requirements of ISO 14045 (2012). For this purpose, 1 kg of removed BOD5 was used as a functional unit and a value function associated with the volume of treated water (m3). Fifteen plants of wastewater treatment in Chile were analyzed, using the life cycle assessment methodology to quantify environmental impacts. The main environmental aspect of domestic wastewater treatment for most of the impact categories studied was electricity consumption. The vermi-biofilter was the most eco-efficient technology for climate change and freshwater eutrophication categories. This result reflecting that unconventional emerging technologies are more eco-efficient than conventional ones.