The epic depletion of naturally occurring phosphorous in the environment, or “Phosphogeddon,” as it is euphemistically called often by some who discount its significance, may be the next great environmental challenge, ranking close with climate change.
As presented in the October 15, 2023, New York Times article, “How Fertilizer Shortage is Spreading Desperate Hunger,” fertilizer scarcity and dramatic price spikes due to a dearth of phosphorus, which was further compounded by the Covid Pandemic and even the war in Ukraine, have impacted agriculture production throughout the world and particularly in Africa and parts of Asia, reducing the ability of farms in those regions to produce enough to sustain the population.
This acute regional shortage, documented by the Times, is in many ways a manifestation of centuries of civilization’s concerted phosphorous depletion. An insightful article from the Atlantic published on February 8, 2021, entitled “Humanity is Flushing Away One of Life’s Essential Elements – We Broke Phosphorous,” highlights the looming crisis. The Atlantic article recounts efforts over a long history to extract phosphorous for farm fertilizer. In the days long before corporate farming separated animals and produce, phosphorous-rich manure from animals sharing farms with food crops provided a continuous ready supply of phosphorous from farm animals for the adjacent produce fields. In 1669, German scientists derived phosphorous from boiling urine. From its discovery in England in the 1840s until today, phosphorous has been extracted from rocks (fossilized feces or coprolites).
Unlike nitrogen, which can be extracted from air, phosphorous is a limited element. Mining coprolites for phosphorous in England, Asia, and the US have depleted the available supply. The last remaining large deposits of phosphorous in rock remain in Morocco and Western Sahara, which reportedly contain three-quarters of the earth’s reserves. Meanwhile, in 2008, the cost of phosphate rock spiked some 800 percent before dropping and then spiking another 400% in 2022 as a result of COVID.
Federal environmental regulation in the US imposed and tightened requirements to remove phosphorous from wastewater to avoid fouling receiving waters with algae blooms and eutrophication. Areas relying on backyard septic systems experience similar impacts to fresh water and coastal ponds. See: “The Cape and Beyond: Alternative Project Procurement for Massachusetts Communities.” But what happens to the phosphorous extracted in the wastewater treatment process? It is chemically or biologically treated and taken up in the sewage sludge solids.
PFAS in sewage sludge produced in wastewater treatment plants led Maine and other states to restrict the use of phosphorous-rich sewage sludge for land application to support agricultural crop production. Numerous promising efforts are underway to develop methods and technology to break down or destroy PFAS, which reopen opportunities to safely use phosphorous-rich sewage sludge in agriculture. “PFAS – Promising Developments.” But even with those encouraging developments for PFAS removal, phosphorous-laden sludge is often managed in remote disposal lagoons or dewatered to produce a cake which is incinerated, with the phosphorous-laden water returned to the wastewater treatment plant where it is chemically treated to remove the phosphorous, producing more sludge which is dewatered and returned to the wastewater treatment plant. The cake is incinerated, and on … and on …trapping the vital, accumulated phosphorous within the wastewater treatment facility in a closed loop.
Many scientists have identified a broken phosphorous cycle that started early this century. Even with the phosphorous remaining in phosphate rock, lasting from 50 to 100, even 400 years by competing estimates, its mining and use have left us with the largest stores in areas of the world that are challenging and perhaps dangerous to access.
Given these geographic and geologic challenges, phosphorous in wastewater and sewage sludge may be the best-untapped source of available and accessible phosphorous for agricultural use. A 2016 report by MIT urged demand management and “increased organic waste recycling” as key components of an effort to avoid “peak phosphorous” with associated impacts on supply and price, similar to the “peak oil” shortages and cost spikes of the recent past. The MIT report suggests the European Union, Canada and the U.S. have made strides.
An effort pursued in Canada used struvite (magnesium ammonia phosphate) produced in the break down of urea in urine. Though struvite generally has a bad name because it is associated with kidney stones and frequently causes clogs in wastewater treatment facilities, it is also a source of slow release phosphate fertilizer. If filtered and collected from the wastewater treatment process, struvite is a valuable source of phosphorous for fertilizer. The product Crystal Green™, based on technology developed by Osatra Nutrient Recovery Technologies using one such method, can recover as much as 90% of wastewater phosphorous. Other technologies include biological recapture of phosphorous and thermochemical treatments. Veolia has developed its own approach to phosphorous (along with ammonia) recovery and harvesting, which it markets as STRUVIA™.
While these developments are promising, resource management and environmental regulatory guidance and direction are required on federal and state levels before wastewater treatment and sludge solids management facilities widely implement them. While efforts to remove PFAS from wastewater sludge is a start, without regulatory guidance and action, the phosphorous needed to support agricultural production to feed a growing population will continue to be trapped in the wastewater treatment and sludge solids management processes or lost to our rivers and coastal waters. Very basically, to avoid “Phosphogedden,” we need to get our _________ together.
