A group of Stanford engineers has developed a cost-effective way to convert a toxic byproduct of the process for making wastewater drinkable again into useful chemicals.
“Hopefully, this study will help accelerate adoption of technology that mitigates pollution, recovers valuable resources, and creates potable water all at the same time,” lead author Xiaohan Shao said in a press release.
Sewage, or wastewater, is simply freshwater that has already been used for drinking, flushing, cleaning, etc. Because of the wide range of water and chemicals included in wastewater, it is crucial that it goes through a treatment facility before going back into the environment.
This wastewater can be purified and be made drinkable once more. One of the most energy-efficient ways to do so is through anaerobic filtration, a process in which bacteria and other microorganisms break down and eat pollutants in the water.
Nonetheless, there is one major downside to anaerobic filtration: the process releases sulfide, which is a toxic and corrosive compound. Workers can be affected and harmed just by breathing it in. The processes for dealing with sulfide, add to the challenge of disinfecting water.
The researchers believe that a possible solution to this problem is to transform the sulfide into chemicals that can be used in manufacturing fertilizers and batteries. However, there is no clear strategy to do so yet.
Now, after thoroughly studying the conversion process and using what they learned, the Stanford engineers have developed a cost-effective, low-energy method for creating the useful chemicals from sulfide.
“We can integrate our process into other advanced wastewater treatment technologies to [make] the gap between wastewater and drinking water smaller,” Shao said.
“And in terms of the chemicals we produce, we are adding these recovered products to the supply chain,” she continued. “It’ll help with agriculture, and in manufacturing, you’ll [reduce] raw material consumption.”
Although the Stanford process seems promising, it is still too soon to tell whether it will actually be integrated into any treatment facilities, since anaerobic filtration , and its sulfide byproduct, isn’t the only way to make wastewater drinkable again.
In places where freshwater is scarce and energy is cheap, recycling and filtration can be the most cost effective ways to boost the supply of drinking water, since the expense of importing water, as other alternatives might not be as energy efficient.
