Engineers in Singapore have developed a new, multistep chemical process that transforms organic waste into useful, sustainable products
In low-lying Singapore, electrochemical engineer Li Hong has found a creative way to displace some of the city-state’s dependence on planet-warming natural gas. Using a new, multistep process, Li and his colleagues have figured out how to perform a surprising bit of climate-helping alchemy by transforming carbon-rich organic trash like shrimp shells into products the island nation needs, including hydrogen gas, food and biogenic calcium carbonate—a white salt used in products ranging from cement to antacids.
Li and his team at Singapore’s Nanyang Technological University report that by diverting waste from the landfill, and by processing it in just the right way, their laboratory proof-of-concept system can produce carbon-negative hydrogen gas. “Carbon negative” means that, overall, the process removes more heat-trapping carbon dioxide from the atmosphere than it produces.
To help reach that carbon-negative status, the chemical process also makes cultured protein—the sort of grown-by-microbes product that fake-meat companies are experimenting with—which can be fed back to farmed seafood, including farmed shrimp. The process “closes the loop from the waste to the food,” says Li, and it employs a waste-to-wealth mind-set.
The third output—calcium carbonate—could help displace some quarried limestone rock in the production of cement, 4.2 billion metric tons of which are produced every year. Juan Carlos Serrano Ruiz, a chemist and an engineer at the Universidad Loyola in Spain who wasn’t involved in the research, says the system is a “very clever” way of using biomass to solve a vexing problem in hydrogen production. “I was really amazed by the degree of integration,” he says.
Fun fact: A promising bio-based building material
One man, Henning Johansen, is doing his part to make construction materials more sustainable. On the island of Laeso in Denmark, he is thatching roofs with eelgrass. The saltwater plant is remarkably effective at removing carbon dioxide from the environment and storing it.
Today, most hydrogen gas is produced by reacting natural gas with steam. This is known as “gray hydrogen.” There’s also a growing supply of “green hydrogen,” which is made using renewable energy like solar or wind.
News courtesy: Smithsonian Magazine