Agro Fossil Free - Methane recovery and reduction of greenhouse gas emissions: WWTP Nuevo Laredo, Tamaulipas, Mexico

Algemene Beschrijving

In this paper, we studied energy recovery from anaerobic digestion of sewage sludge in Waste Water Treatment Plants (WWTP), as a mechanism to reduce Greenhouse Gas (GHG) emissions and improve energy efficiency. We analyzed the case of the International Wastewater Treatment Plant at Nuevo Laredo (WWTP-NL), which is considered energy efficient and produces good quality sewage sludge. We utilized a benchmarking approach based on a multiparametric model with six key variables to evaluate the energy use efficiency of the WWTP-NL. The prospective electric energy production was estimated based on the potential amount of methane recovered. Then, we compared baseline and projected GHG emissions. For this purpose, we used the Clean Development Mechanism (CDM) methodology to project the recovery of biogas in wastewater by introducing an anaerobic treatment system for sludge treatment. The main findings of this prospective exercise are that the implementation of an energy recovery project in the WWTP-NL would: reduce the plant's GHG by 21%; supply 14% of the energy required by the plant; and improve the energy efficiency of the plant by 2%. Specific technical, legal and economic feasibility studies are required for the practical implementation of this theoretical energy WWTP recovery project; nonetheless, this exercise shows that the project would generate clear environmental benefits.