Scientists have an unexpected solution for protecting coastal areas and infrastructure elements: charging the shore with electricity.
In a study published in the scientific journal Communications Earth and the Environment, researchers from Northwestern University have demonstrated a technique to strengthen marine sand, offering a potential solution to combat coastal erosion.
"Over 40% of the global population lives in coastal areas. Due to climate change and rising sea levels, erosion poses a huge threat to these communities. By deteriorating infrastructure and land loss, erosion causes billions of dollars in damage worldwide every year," stated Alessandro Rotta Loria, the study's lead, in a press release.
The researchers drew inspiration from marine creatures such as clams, which use minerals dissolved in seawater to form their shells. They utilized these same minerals to create a natural cement between sand grains, but they did so with the help of electrical energy instead of metabolic processes, as reported by Newsweek.
The method involves applying a mild electric current to marine sand, triggering a chemical reaction in which minerals are converted into solid calcium carbonate, magnesium hydroxide, or hydromagnesite. These minerals act as binders, transforming soft sand into a hard substance.
Utilizing natural cementation processes is not a new method for land works, but it could be a solution to halt coastal erosion.
Current strategies, such as building seawalls and injecting cement into affected areas, come with high costs and environmental impacts. "Not only do these methods have a huge cost per kilometer, but they don't even last. They often suffer damage or even collapse," explained Alessandro Rotta Loria.
Laboratory experiments on various types of sand, including silicon, limestone, and iron sands, have shown promising results, demonstrating the versatility of this method. The process is nearly instantaneous, but prolonged electrical stimulations yield better results.
"We observed remarkable results after just a few days of stimulation. Then, the treated sand should stay in place without further interventions," said Rotta Loria.
Furthermore, the new method is environmentally friendly and reversible, minimally impacting marine life and allowing for the dissolution of solidified sand if necessary.
The estimated costs indicate significant savings compared to conventional shoreline consolidation methods. The electrical cementation process costs approximately $3-6 per cubic meter of treated land, while traditional techniques can cost up to $70 for the same volume.
According to the researchers, the method has numerous applications. "We can use it to strengthen the seabed beneath seawalls, to stabilize sand dunes, and to stabilize unstable soil slopes. We could also use it to reinforce protective structures, marine foundations, and many other things. There are many ways to apply this to protect coastal areas," explained Rotta Loria.
The research team now plans to conduct field tests to validate the method's efficiency under real conditions.
They will implement this technique using conductive geotextiles - fine metal networks capable of conducting electricity.
T.D.