Solutions Challenge: Greenhouse gases in developing economies
Methane to Aquaculture Feed
Economic development, urbanization and population growth are associated with increased waste generation. Management of solid waste, though landfills or wastewater treatment, is in turn a major source of greenhouse gas emissions. Globally, waste management constitutes up to 12% of global anthropogenic emissions of methane, a potent greenhouse gas with at least 25 times the global warming potential of carbon dioxide. In Africa, Asia, and Latin America, waste constitutes 5–10% of all urban greenhouse gas emissions. With low-income countries expected to triple waste production by 2050, reducing the climate change impact of landfills is essential for sustainable economic growth in developing economies.
When organic waste decomposes in landfills and dumpsites, it produces a gaseous mixture of methane and carbon dioxide. Methane, an energy rich molecule and the primary constituent of natural gas, is often emitted directly to the atmosphere because it is uneconomical to capture, clean and use. However, methane can serve as a feedstock for methanotrophic bacteria: microorganisms that use the gas as their primary source of carbon and energy for growth. The resulting methanotrophic biomass is rich in protein, and can serve as a component of animal feed, offsetting the current practice of using unsustainably harvested fishmeal. To date, most companies advancing this technology are using natural gas and therefore not reducing our dependence on fossil fuels. A recent techno-economic analysis conducted by the Stanford research team finds that using methane emitted or flared from industrial sources in the United States can be economically competitive with fishmeal. The team will attempt to adapt this innovative technology to use waste-derived methane from landfills instead of natural gas. By transforming it into a high-value product, we can incentivize capture of a potent greenhouse gas and directly reduce emissions. The team plans to develop and pilot their system in Bangladesh.
Team:
Professor Stephen Luby (School of Medicine)
Professor Craig Criddle (CEE)