Phantastic Phosphorus

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As a child, one of my favorite stories was Isaac Asimov’s Fantastic Voyage, which he adapted from the 1966 movie by 20th Century Fox Films (versus the other way around.) Best known for his science fiction, Asimov also wrote about science, including an essay about phosphorus entitled “Life’s Bottleneck.” Asimov describes how phosphorus is an essential chemical contained in all living organisms. “[L]ife can multiply until all the phosphorus is gone, and then there is an inexorable halt which nothing can prevent,” he wrote. “We may be able to substitute nuclear power for coal, and plastics for wood, and yeast for meat, and friendliness for isolation—but for phosphorus there is neither substitute nor replacement.”

As a child, I made a Proteus submarine replica out of balsa wood, complete with a lookout on top. I made it from a clear plastic prize container that I got out of a 25¢ bubble gum machine. There is no replicating a young Raquel Welch, though. ©1966 Twentieth Century Fox Film Corporation

Phosphorus in the human body helps filter out waste in the kidneys and plays an essential role in how the body stores and uses energy. Phosphorus is needed for the growth, maintenance, and repair of all tissues and cells, and for the production of the genetic building blocks, DNA and RNA. It’s an essential chemical for plant growth.

As far back as 1938, President Franklin Roosevelt warned Congress about potential phosphorous shortages. Nothing was done. And now, it is estimated that the earth will be exhausted of phosphorus within 100 years. Where is it going? It’s running off farm fields through soil erosion and runoff, and down swirling toilets, through human waste. But we can recover this precious substance through wastewater treatment plant biosolids and extract it from side-stream processes, such as Ostara.

When Phosphorous is Not Viewed as Precious

With eutrophication of waterways and hypoxic zones growing in the Gulf of Mexico and Chesapeake Bay, the US EPA is targeting municipal wastewater treatment plants as a point source dis-charger of phosphorus. Communities within the Great Lakes Initiative have had effluent phosphorus limits of 1.0 mg/L for some time, but stricter limits have been proposed in WI, as low as 0.07 mg/L. Very recently, in Connecticut regulators have proposed limits of 0.2 mg/L phosphorus that officials say will cost tens of millions in treatment plant upgrades.

Just recently the EPA created a website to monitor nutrient sources. It is generally accepted that point sources, including treatment plants, account for about 30-40% but stormwater runoff and agriculture accounts for the largest fraction. Combined with erosion and loss of topsoil, our agriculture industry relies on more and more fertilizer. So the irony is that the wastewater treatment plants are targeted as sources of phosphorus because of their effluent, but they can also be a solution for returning nutrients to the land and standing in for fertilizer.

Biosolids from Treatment Plants Can Provide Beneficial Phosphorous

The benefits of land applied biosolids were recently substantiated by researchers in Washington[1]. Biosolids improve moisture holding capacity and tilth of soil, and so nutrients like nitrogen and phosphorus are better retained and more readily available to plants. Unfortunately, the lack of knowledge about the efficacy of biosolids and the perception that they are toxic means that only about half of all biosolids produced in the US are land applied. Yes, biosolids contain metals, but with EPA 503 regulations and industrial pretreatment requirements, heavy metals in biosolids should not be an issue.

Unfortunately, many communities landfill biosolids as the simplest answer to its management. But with phosphorus resources rapidly diminishing, our thought leaders should begin advancing the idea of land application to optimize this precious element. Wastewater treatment plants should continue to reduce nutrients in discharges but they can also provide nutrients for the agricultural industry. What factors are standing in the way and what do we do about them?

[1] Brown, Sally, Kate Kurtz, Andy Bary, and Craig Cogger. 2011. “Quantifying Benefits Associated with Land Application of Organic Residuals in Washington State.” Environmental Science & Technology. Vol. 17 (7), pp. 7451-7458.

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2 Replies to “Phantastic Phosphorus

  • T.H. Culhane on said:

    Wonderful and important post Mike! I attended a lecture on this exact subject by Dr. Martin Denecke at the University of Essen here in Germany called “The Golden Stream: Recovering Phosphorous from Waste Water”. Denecke is also the patent holding inventor of the 3A Biogas system for turning municipal vegetation and paper wastes into gas and fertilizer. His recommendation to German government and industry was that we install more separating toilets in public facilities and capture the urine stream directly and extract the phosphorous at lower cost from ‘the golden stream’; don’t know how the costs of installing the new toilets and infrastructure would balance out, but it was intriguing. I think you are right — we need to amp up our public awareness of this important limiting resource and the ‘golden’ future that awaits if we are smart enough to recover it (there just ain’t that much bat guano to mine if we want to keep extracting from nature…)

  • Tim Evans on said:

    Culhane is right, phosphorus is an important issue, well done for raising it. Just one small point of correction, it is today’s mines that will be exhausted in less than 100 years at the current rate of extraction. Then there are future reserves of rock containing less P and more cadmium (an adventitious heavy metals that substitutes into sedimentary P rock) but these will only last 200 to 300 years. So it is not quite as dire but because P is essential and non-substitutable it is a really serious issue and one we must grasp now. To quote another US president – J. F. Kennedy: “The great French Marshall Lyautey once asked his gardener to plant a tree [to shade his troops]. The gardener objected that the tree was slow growing and would not reach maturity for 100 years. The Marshall replied, ‘In that case, there is no time to lose; plant it the afternoon.'”
    Urine diverting toilets are interesting but we are not going to retrofit cities with urine conveyance infrastructure so we have to start capturing it from municipal wastewater, including as Michael says, using biosolids as phosphate fertilizer.
    The significance is that 98% of the P consumed by adults is excreted because we are just turning over cells; juvaniles are accumulators but adults pass it on.
    CIWEM.org has published a good summary Policy Position Paper at http://tinyurl.com/9egmuf3
    We can live [albeit uncomfortably] on a warmer planet but we can’t live on a planet without P; well not many of us.

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