The nitrogen that is recovered from the same process reduces greenhouse gas emissions. Waste treatment systems can be reengineered to produce or extract unwanted struvite, a phosphorus-rich compound that can be used in agriculture but also in such things as flame retardants and lithium-ion batteries. That means not only the financial value, but rather the total value of phosphorus recovery, which includes other materials recovered at the same time, and many services to society and the environment. There are already 400 permanent hypoxic dead zones in water bodies around the world, including the vast Gulf of Mexico, and near other cities in the developing world with limited treatment capacity.Īside from more investments in costly phosphorous removal, a smarter answer to this tragic situation is to increase the value of phosphorus to make it worthwhile to extract, before, during or after wastewater treatment. For example, Istanbul discharges most of its untreated sewage into its waterways, The blooms suck the oxygen out of the water, killing other forms of life, so phosphorus in the Bosporus is becoming a problem there. “So, as a finite resource, the phosphorus is ultimately lost in our lakes and oceans, because natural processes cannot handle so much of it.”Įxcess phosphorus allows algae and other organisms to grow or ‘bloom’ out of control in the water. “Recovering that phosphorus from wastewater costs normally several times more than using new supplies,” said Pay Drechsel, a theme leader at the International Water Management Institute ( IWMI) and a co-author of the paper. Our bodies do not need most of the phosphorus that we eat with our food, so we excrete it. Phosphorus is still cheap, and it is mined at a rate of around 20 million tonnes a year. A recently published paper in Environmental Science and Technology offers a convincing case to make phosphorus recovery, recycling, and reuse worthwhile. Even though the damage that phosphorus does to the environment is obvious-algal blooms killing thousands of fish are hard to miss-there is little economic incentive to prevent it, or to recover the phosphorus. The Earth has enough potassium to last hundreds of years, but many experts are convinced that the supply of phosphorus-bearing ores will not last much past 2100. Nitrogen is extracted from the air, while potassium and phosphorus are mined. It is not exaggerating to say that the whole global food system relies largely on these three minerals.
A blessing, because it lets us grow more food a curse, because it pollutes our water and destroys waterways and coral reefs.Īlong with nitrogen and potassium, phosphorus makes up the bulk of the fertilizers that produce the superb yields that feed the Earth’s population. Phosphorus is both a blessing and a curse.