When you flush the toilet, you're sending a lot of bad stuff into the sewer. But what you might not realise is that you're flushing away a lot of good stuff, too. That's why a team of German scientists have developed a method for recovering those valuable particles.
Specifically, researchers found a way to remove phosphorus from wastewater. They call the program, appropriately, the German Phosphorus Platform, and it's both strikingly simple and impressively sophisticated. The platform adds something called superparamagnetic particles to the water. When the particles detect a magnetic field, they themselves become magnetic. The phosphorus particles then end up "piggybacking" off the superparamagnetic particles and can be removed from the water with a magnet.
Phosphorus is a complicated substance: it's a valuable ingredient in things like fertiliser and detergents, but it's also a pollutant in waterways. The use of superparamagnetic particles works with other substances, too, however. For example, "other hazardous substances, such as toxic heavy metals, can also be removed relatively easily with magnets," Dr. Carsten Gellermann of Fraunhofer said in a press release. But the phosphorus thing is a big deal. After all, we only have enough reserves to last for the next 250 years, perhaps turning our sewers into the phosphorous mines of tomorrow. [Frauenhofer]