In the heart of ancient Rome, nothing went to waste. While today projects like P2GreeN are developing innovative solutions to recover nutrients from organic waste, the Romans had already understood the hidden value of what we now call “waste.”
One of the most fascinating examples? Urine. In Roman times, it was collected in fullonicae, the industrial laundries of the day, where it served as a natural detergent thanks to its ammonia content. It was so valuable that Emperor Vespasian imposed a tax on its collection, the famous vectigal urinae, which gave rise to the expression pecunia non olet (“money doesn’t stink”).
But that’s not all. Organic waste, food scraps, animal dung, sludge was often reused in agriculture as a natural fertilizer, a rudimentary form of what we now call a circular economy.
Today, the EU-funded P2GreeN project looks to the past to build the future. Its mission? To recover phosphorus and other vital nutrients from wastewater and organic residues, and return them to agricultural soils, reducing our dependence on chemical fertilizers and closing the nutrient loop.
As Cicero once wrote, “Stercora enim sterquiliniis proiciuntur.” Excrements may have once been cast onto dung heaps, but today, we choose to see their hidden value.
This is precisely what P2GreeN is doing in its pilot regions, such as Sweden, where innovative systems are being tested to safely collect and process human urine and organic waste for use in local agriculture, turning yesterday’s waste into tomorrow’s harvest.
With projects like P2GreeN, Europe is rediscovering a lesson as old as Rome: waste can be a resource. By turning wastewater and organic residues into valuable nutrients for agriculture, P2GreeN brings circularity to life, proving that sustainability starts with what we choose not to throw away.
