Reduction of Greenhouse Gas Emissions From Municipal Wastewater Treatment in Mexico Based on Technology Selection

As do many developing countries and emerging economies, Mexico needs to invest in wastewater treatment facilities, which has been neglected in the past. Currently, 45% of municipal sewage enters a treatment plant, so a significant fraction of untreated or partially treated water is discharged or used for crop irrigation. This has significant impacts on public health and the environment. In this context, the proper selection of treatment technologies may be an important opportunity for contributing to the ambitious national greenhouse gas (GHG) emission reduction goals in Mexico. Based on actual infrastructure data, the scenarios analyzed in this work show that emission reductions from sewage treatment plants in Mexico could be as high as 34% when compared to the baseline scenario, depending on the treatment technologies. The results show that the anaerobic + aerobic scenario is a better option than the full aerobic scenario, as it would achieve a 4% GHG emission reduction by the year 2030. Moreover, if methane is used for in situ electricity cogeneration in larger facilities, the reduction reaches 27% versus the full aerobic scenairo. The results may be helpful to policy and decision makers to evaluate the cost effectiveness and feasibility of possible GHG mitigation strategies for wastewater treatment facilities, mainly for new infrastructures in developing countries.