March 08, 2022

New Process Could Mine Sewerage Water for Useful Chemicals

History tells us that alchemy was a pseudo-science that could transform lead into gold, although current scientific breakthroughs are so bewildering at times that the average person would think it’s alchemy – especially when researchers say they can find “treasures” in our sewers.

Scientists at Stanford University in Santa Clara County, California claim to have recently discovered a process that could potentially provide precious chemicals and clean drinking water from wastewater.

Will Tarpeh, an assistant professor of chemical engineering at Stanford University and senior author on the study, said: “We are always looking for ways to close the loop on chemical manufacturing processes.”

“Sulphur is a key elemental cycle with room for improvements in efficiently converting sulphur pollutants into products like fertiliser and battery components,” he added.

To meet this requirement, they looked to electrochemical sulphur oxidation.

In layman’s terms, this is the process of electrochemically converting the sulphides in sewerage water to something more valuable like sulphuric acid, which is a critical component in manufacturing.

Sulphur is a major byproduct of filtering the aforementioned wastewater into drinking water – which uses no electricity – thus making the process invaluable.

So, essentially fine-tuning the entire process of sulphur oxidation could mean it can be scaled to service entire cities while using renewable energy. When combined with techniques to capture nitrogen, it may directly produce ammonium sulphate, which has many commercial applications but mostly in soil fertiliser.

Lead author, Xiaohan Shao, said: “Hopefully, this study will help accelerate adoption of technology that mitigates pollution, recovers valuable resources and creates potable water all at the same time.”