Water

Sewage can be purified for drinking and can be taken as a treasure

Weatherwell

Wastewater treatment produces toxins, but scientists think they can turn them into treasures.

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In a world where one in four people has no access to clean drinking water — a disproportionate number of whom live in impoverished areas — scientists have been steadily figuring out ways to purify wastewater so it can be added back to humanity’s freshwater supply .

A mechanism known as anaerobic filtration has been leading the way because it uses very little energy to convert large volumes of sewage into a consumable form. But there is an obvious problem. When purifying water, anaerobic filtration tends to produce dangerous by-products called sulfides. These are extremely harmful to our health and the environment.

For example, the Centers for Disease Control and Prevention writes that inhaling hydrogen sulfide may cause symptoms such as difficulty breathing, tremors, eye and skin irritation, loss of consciousness, and even death in high concentrations. You just need to be close enough to the chemical to inhale it, which means the on-site workers at the sewage treatment plant are on the line.

In a paper published Wednesday in the journal ES&T Engineering, researchers at Stanford University tackle this pressing dilemma and reveal a way to redefine the so-called cost of anaerobic filtration as a hidden treasure. The team has not only developed a fascinating way to convert toxic sulfides in wastewater into safe compounds, but also into an extremely valuable resource for agriculture and rechargeable technologies.

“We’re always looking for ways to close the loop in the chemical manufacturing process,” Will Tarpeh, assistant professor of chemical engineering at Stanford and senior author of the study, said in a statement.

Typically, according to this study, scientists try to solve the sulfide problem by using certain chemicals to separate sulfur derivatives into non-toxic components. However, this often corrodes purification system pipes, reducing the overall efficiency of clean water production, the researchers said.

On the other hand, the team behind the new study treated sulfides by employing what’s called electrochemical sulfur oxidation. “The process I’m working on is the electrochemical conversion of sulfides in wastewater into more valuable substances, such as sulfuric acid, which can be used in many manufacturing processes and fertilizers,” said Dr. Xiaohan Xiao. Stanford’s civil and environmental engineering student and lead author of the study, said in a video overview of the study.

Basically, this electrochemical system gives researchers the option to convert toxic sulfides into other sulfur derivatives, completely eliminating the threatening chemical in anaerobic filtration. According to the team, the procedure requires so little energy that it can be powered entirely by renewable energy and applied to the sewage supply across the city.

“We can integrate our process into other advanced wastewater treatment technologies to [make] The gap between wastewater and drinking water is smaller,” Shao said in the video overview. “As far as the chemicals we produce, we are adding these recycled products to the supply chain, which will help in agriculture and manufacturing. ,You can [reduce] Raw material consumption. “

Shao is one of a cadre of scientists working to address global water scarcity, some of whom are focusing on self-sufficient solar panel systems that can pump water from thin air. “Hopefully this research will help accelerate adoption. Technologies to mitigate pollution while reclaiming valuable resources and creating drinking water.”

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