Life-cycle assessment of wastewater treatment plants

Abstract

This thesis presents a general model for the carbon footprints analysis of wastewater treatment plants (WWTPs), using a life cycle assessment (LCA) approach. In previous research, the issue of global warming is often related to traditional industries with high carbon dioxide (CO2) emissions, such as power plants and transportation. However, the analyses of wastewater treatment plants (WWTPs) have drawn increasing attention, due to the intensive greenhouse gas emissions (GHG) from WWTPs. WWTPs have been listed in the 7 th place for both methane (CH 4) and nitrous oxide (N2O) total emissions. In addition, WWTPs indirectly contribute to a huge amount of CO2 emissions. The final results have shown that more than half of the carbon footprints from the La Gavia WWTP are from the indirect emissions of CO2, which is caused by the intensive energy consumption. The direct emissions of CH4 and N2O combined contribute more than 30 percent of GHG emission. The finally section of the thesis compares the environmental impacts of the La Gavia WWTP with case of no WWTP at all. It has been concluded that although the La Gavia WWTP increased the total carbon footprints, it has much better control of eutrophication potential (EP).