Wastewater isn't typically considered a precious resource, but a team of researchers based in Spain is showing just how valuable it can actually be.
The scientists recently developed a way to turn sewage into clean energy using a type of purple bacteria, according a new study published Tuesday in the journal Frontiers in Energy Research.
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Industrial and domestic wastewaters contain organics and nutrients, which are key for energy production, and the purple phototrophic bacteria has the unique ability to recover energy from such organic waste. Like leaves, the bacteria also capture energy from the sun through photosynthetic pigments.
Scientists conducted experiments to speed up and manipulate the bacteria's metabolism to generate the most energy possible and found that when supplied with an electric current, the bacteria can pull 100% of carbon from any type of organic waste, turning it into hydrogen gas that can be used for fuel.
Not only can the bacteria soak up greenhouse gases — it can transform sewage into a sustainable source of energy. And harnessing its power could be a game-changer for wastewater management.
While the energy potential of wastewater has been discounted, so has its impact on the environment. Wastewater treatment plants are responsible for an estimated 3% of greenhouse gases, according to a study published in 2016.
One of the most important problems of current wastewater treatment plants is high carbon emissions," Dr. Daniel Puyol, co-author of the report, said in a press release.
"Our light-based biorefinery process could provide a means to harvest green energy from wastewater, with zero carbon footprint," he said.
As countries work to uphold the Paris agreement and reduce their fossil fuel emissions, wastewater management is a key area for innovation. The wastewater industry, which is currently an energy consumer, could soon be a major energy provider.