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ISSE Seed Project: Assessment of Methane Resources from Municipal Wastewater in Chile

Team: Qiang He, Chris Cox, and Gregory Reed, Civil & Environmental Engineering; Christian Seal, Department of Civil Engineering, Universidad de Santiago de Chile

2014-2015 Report

In order to reduce the release of methane as a potent greenhouse gas and curb global warming, methane emission from various anthropogenic sources has been extensively evaluated. However, municipal wastewater treatment facilities as a significant source of methane emission has not received much attention, making it critical to systematically assess technologies and management practices for the reduction and recovery of methane from wastewater. Economic and technical feasibility typically represents the primary obstacles to the implementation of efficient wastewater treatment processes to reduce methane emission. With the ability to capture methane as renewable fuel instead of releasing methane as a greenhouse gas, anaerobic digestion is a sustainable technology with great potential in reducing the disposal costs for municipal waste sludge generated from wastewater treatment and the recovery of biogas/methane as a renewable energy, providing a promising technical option for improved implementation of wastewater treatment and reduction in methane emission. Notably, the biogas-fueled combined heat and power (CHP) technology could further augment the economic and environmental benefits of anaerobic digestion, which warrants a comprehensive assessment in tandem with anaerobic digestion for methane recovery.

picture of conference flyer

Therefore, using Chile as a model, the objective of the EPA-supported project is to evaluate the potential of anaerobic digestion and CHP technology for the recovery of methane from wastewater treatment plants. The joint U.S.-Chile team have completed the following tasks: 1) Evaluation of municipal waste sludge as significant methane resources in Chile; 2) Technical and economic evaluation of anaerobic digestion for methane recovery from municipal waste sludge; 3) Technical and economic evaluation of CHP technology for enhanced utilization of methane generated from anaerobic digestion; 4) Evaluation of the potential of anaerobic digestion and CHP for reducing methane and CO2 emission in Chile.

Results from this proposed project provide much needed guidance for selecting environmentally and economically sustainable technologies for reduced methane emission and improved methane recovery in Chile. The culminating outcome of this project is the “Simposio Internacional Emisiones de Metano, Medio Ambiente y Sustentabilidad” held at Santiago, Chile June 17-18, 2015. Project team lead, Dr. Qiang He, co-chaired this international symposium with team partner Dr. Christian Seal. The symposium was attended by researchers from the US and Chile as well as representatives from the Chilean government and US EPA. Dr. He represented the project team and gave a keynote presentation on findings from this project.

Results from this proposed project will provide much needed guidance for selecting environmentally and economically sustainable technologies for reducing methane emission and enhancing methane recovery as a renewable energy. The outcomes of this project include the reduction of methane emission as a potent greenhouse gas that will benefit the U.S. and other countries from the mitigation of climate change, and the promotion of U.S. technology and expertise for enhanced methane capture and use in Chile and the world clean energy market.

2013-2014 Report

With the support of ISSE, Dr. He’s research group focused on the assessment of methane resources in the wastewater industry and the development of innovative strategies to enhance the production of methane from wastewater.

Building upon past methane research supported by ISSE, a research team led by Dr. He secured funding from the highly competitive U.S. EPA Global Methane Initiative (GMI) program for the “Assessment of Methane Resources from Municipal Wastewater in Chile”. Methane is a greenhouse gas (GHG) that is 21 times more potent than carbon dioxide in global warming potential. Municipal wastewater represents one of the important sources of methane emission. However, methane is also a clean and renewable source of energy. Therefore, the recovery of methane from wastewater, specifically by anaerobic digestion, has been practiced in the U.S. and other developed countries to reduce GHG emission and produce renewable energy. The recovery of methane as a resource from wastewater, however, has been hindered by technical and economical obstacles in less developed countries, such as Chile. Joined by our collaborators in Chile, Universidad de Santiago de Chile, the project team will use Chile as a model to evaluate the technical and economical feasibility of anaerobic digestion and combined heat and power (CHP) technology for the recovery of methane from municipal WWTFs as a clean fuel (see schematic below). In March 2014, the research team attended the Global Methane Initiative Tri-Sector Sub-Committee Meeting for Agriculture, Municipal Solid Waste and Municipal Wastewater in Brazil and presented preliminary results. The research team also held project meetings at Santiago, Chile, in March 2014 with Chile Ministry of Environment and the Chile national wastewater regulator Superintendencia de Servicios Sanitarios to facilitate data sharing. As a result, important progress has been made in the collection of a comprehensive dataset of the wastewater industry in Chile. In-depth data analysis is currently on-going.