Peak phosphorus

  1. The problem: 50 to 100 years left
  2. The solution: seaweed fertiliser and other recycling systems below
  3. Recycling from sewage
  4. Local green bins, local rubbish, local sewage
  5. Aldous Huxley understood this in 1928!

1. The problem: 50 to 100 years left

Put simply, every time we flush our toilets we flush phosphorus out to sea, and it is pretty much permanent. This page will explore how to save the phosphorus we have left, and how we might even recover some of the phosphorus we’ve already flushed out to sea.

It is so important to life that it has shaped history.

Phosphorus is essential to all life forms. It is essential for DNA, RNA, ATP and many other biological functions. There is no substitute – it’s present in every cell. Without phosphorus you would quickly die. Fortunately almost every diet contains more than enough of the RDA of 0.8g. Phosphorus makes up 1% of our bodyweight although this is locked up in cells and bones. The phosphorus in food is utilised and then all of it is excreted.

Phosphorus clearly seemed important to Roosevelt, and the reason was because of fertilizer. Phosphorus is an integral part of fertiliser (NPK (nitrogen, phosphorus, potassium). In most cases the reason for reduced yield is insufficient phosphorus. In natural ecosystems, the most common reason they can’t expand is because of a lack of phosphorus. One of the reasons early Americans headed west was because eastern fields became phosphorus deficient.

Unlike the nitrogen that makes up 80% of our air and that thunderstorms naturally replenish in our soil, phosphorus is a rare mineral currently on a one-way trip down our toilets to the bottom of the ocean. If we need more nitrogen, we can easily mimic a lightning storm using the Haber process, or grow legumes that fix nitrogen into our soils naturally in a crop rotation cycle. But phosphorus isn’t like that. It’s a mineral.


When we flush it down the toilet, it pretty much stays down there. Our enormous challenge is to stop flushing phosphorus down the toilet and out to sea, but to try and reclaim it from our sewerage systems. Then even eating seafood might gradually return phosphorus to our agricultural system.

So we must create closed nutrient cycles, and stop flushing this irreplaceable resource out to sea. As the wiki says:

According to some researchers, Earth’s phosphorus reserves are expected to be completely depleted in 50–100 years and peak phosphorus to be reached in approximately 2030.[2][3]

Phosphorus mining may peak in the next few decades. As the USGS bluntly puts it:- “Substitutes: There are no substitutes for phosphorus in agriculture.”
(United States Geological Survey PDF).

Phosphate production is predicted to peak around 2030 as the global population expands to a predicted 9.1 billion people by 2050. And unlike oil, where there are renewable energy alternatives to fossil fuels, there is no substitute for phosphorus, according to the US Geological Survey.
Guardian: 2010

World’s phosphorus situation scares some scientists
Coloradoan — March 2008
Phosphorus, the most critical element by Folke Gunther
Energy Bulletin’s Summary, Background reading, Peak Phosphorus.
Also see a review by Mobjectivist.

2. The solution: seaweed fertiliser and other recycling systems below

As I have said repeatedly we’ve got to stop sending all our fertiliser nutrients out to sea. The coastal kelp farms that Bren Smith and others have raved about could capture those nutrients leaking out to sea, grow abundant seaweed and shellfish that could in themselves feed the world, but also gives us abundant fertilisers to bring back to the land.

3. Recycling from organic wastes and sewage

Organic wastes

Western Europe imports all of its phosphate for agricultural use, but Professor Chambers from environmental consultancy ADAS, believes that more than 50 per cent of the UK’s total requirement could come from organic sources, saving the agricultural industry between £20m and £30m a year…

The solution could lie in recovering phosphate from organic waste that currently ends up being sent to landfill. The UK produces about 100 million tonnes of organic waste each year, which could generate up to seven per cent of the UK’s renewable energy by 2020, according to the Department for Environment, Food and Rural Affairs (Defra)…

The coalition government has already pledged to lead the UK towards a zero-waste economy, and a development programme of anaerobic digestion (AD) plants is a major step in that direction. There are currently 37 AD plants in the UK, with another 60 either under construction or at the planning stage.

AD plants not only generate energy while helping to reduce emissions and landfill waste, but they also produce “digestate” once the fuel has been burned, which is high in nutrients and can be used as organic fertiliser.
Guardian: 2010


The Rock and a Hard Place 2010 report by the UK’s Soil Association (23 page PDF) makes some interesting points.

  • Concern about heavy metals is reducing as new industrial waste processes remove it from our sewage.
  • Agricultural wastes should be used including lifestock manure and composting of plant wastes. Page 13 says about half the world’s lifestock manure ends up in landfill or washing away in rivers!
  • Micro-organisms and micro-fungi increase phosphorus uptake in plantsn (which I note is another useful effect of biochar — see below).
  • Urine (when separated from the waste stream) could provide about half the phosphorus necessary for cereal crops.
  • Urine can be stored in local tanks and collected once a year, while other collection methods are proposed for pooh.

Existing sewerage systems can implement Enhanced Biological Phosphorus removal while all new homes and streets should be connected to the local collection tanks mentioned above.

As the Oxford Journal BioScience says:

The Green Revolution has led to a threefold growth in food production in the last 50 to 75 years, but increases in crop production have required a concurrent increase in the use of inorganic phosphorus as fertilizer. A sustainable phosphorus supply is not assured, though, and food production depends on mineral phosphorus supplies that are nonrenewable and are being depleted. Phosphorus is effectively a nonsubstitutable necessity for all life. Because mineral phosphorus deposits are not distributed evenly, future phosphorus scarcity may have national security implications. Some projections show economically viable mineral reserves becoming depleted within a few decades. Phosphorus-induced food shortages are therefore a possibility, particularly in developing countries where farmers are more vulnerable to volatile fertilizer prices. Sustainable solutions to such future challenges exist, and involve closing the loop on the human phosphorus cycle. We review the current state of knowledge about human phosphorus use and dependence and present examples of these sustainable solutions.
BioScience (2011) 61(2): 117-124.doi:10.1525/bio.2011.61.2.6

BioScience (2011) 61(2): 117-124.doi:10.1525/bio.2011.61.2.6

From agricultural use of sewage sludge to nutrient extraction: A soil science outlook, by Holger Kirchmann,corresponding author Gunnar BörjessonThomas Kätterer, and Yariv Cohen

In order to avoid ash deposition, the development of new technologies treating ash to produce concentrated and clean fertiliser products that can substitute for mineral fertiliser is a possible way forward (Fig. 3). The advantages are apparent: (1) Use of the raw material apatite for phosphorus fertiliser production can be reduced and replaced with ash; (2) extracted fertiliser products can have as high water solubility as those on the market, which means highest nutrient availability for crops; (3) concentrations of unwanted contaminants are very low and; (4) transportation of recycled nutrients back to remote cropland becomes possible, enabling equitable distribution.

4. Local city inputs

Local green bins

Local council green bins should collect garden waste and kitchen food scraps. Many city people are not that interested in gardening or running their own composts. So the answer could be placing kitchen scraps in biodegradable plastic bags and throwing them in the green bins, which the councils then collect and process in a local centre. As the ABC environment podcast says:

A lot of kitchen waste is dumped into landfill. At the same time, farmers are crying out for nutrients to add to their soils. The solution is obvious. Someone should collect all those scraps and turn them into compost. Kim Russell has taken on the challenge.
He’s executive director of Zero Waste Australia and he wants to get organic waste out of landfill and onto farms.

Local rubbish

See my Recycle page for a garbage sorting company that collects organics out of household waste and composts them into a farming loam 3 times richer than backyard composting! This could be scaled up to process all of Sydney’s waste, separating out the batteries and plastics and glass and paper, and then composting all the organics that are left over. I don’t wish to repeat everything on my rubbish recycling page here, except merely to point out that some spoiled food wastes can either be composted in these recycling centres, or added to sewage waste centres to run through a digester there. As Yale Environment reports:

Waste Management collects food scraps from restaurants, grocery stores, hotels, and food processing plants, takes them to a company facility in Carson City, and grinds them into a slurry. That liquid is taken to a Los Angeles County wastewater treatment plant, where it is mixed in with sewage — one part food waste to nine parts human waste — and processed in an anaerobic digester.  The end result? Biogas that can be burned as fuel — a benefit that may encourage the Los Angeles County Sanitation District to expand the initiative into a full-scale program after two years.

Local sewage

Some sustainable agriculture planners are so concerned about peak phosphorus (and other fertiliser problems and soil inefficiencies) that they are even designing town plans around the quickest way to get nutrients back to the soil! But given that local urine collection tanks only require emptying once a year (see above under peak phosphorus) I’m not sure we have to design our entire town plan around phosphorus cycles!

5. Aldous Huxley understood this in 1928!

Aldous Huxley, Point Counter Point (novel published in 1928)

… Lord Edward started at the word. It touched a trigger, it released a flood of energy. “Progress!” he echoed and the tone of misery and embarrassment was exchanged for one of confidence. “Progress! You politicians are always talking about it. As though it were going to last. Indefinitely. More motors, more babies, more food, more advertizing, more money, more everything, forever. You ought to take a few lessons in my subject. Physical biology. Progress indeed! What do you propose to do about phosphorus, for example?” His question was a personal accusation.

“But all this is entirely beside the point,” said Webley impatiently.

“On the contrary,” retorted Lord Edward, “it’s the only point.” His voice had become loud and severe. He spoke with a much more than ordinary degree of coherence. Phosphorus made a new man of him; he felt very strongly about phosphorus and, feeling strongly, he was strong. The worried bear had become the worrier. “With your intensive agriculture,” he went on, “you’re simply draining the soil of phosphorus. More than half of one per cent a year. Going clean out of circulation. And then the way you throw away hundreds of thousands of tons of phosphorus pentoxide in your sewage! Pouring it into the sea. And you call that progress. Your modern sewage systems!” His tone was witheringly scornful. “You ought to be putting it back where it came from. On the land.” Lord Edward shook an admonitory finger and frowned. “On the land, I tell you.”

“But all this has nothing to do with me,” progrested Webley.

“Then it ought to,” Lord Edward answered sternly. “That’s the trouble with you politicians. You don’t even think of the important things. Talking about progress and votes and Bolshevism and every year allowing a million tons of phosphorus pentoxide to run away into the sea. It’s idiotic, it’s criminal. it’s … it’s fiddling while Rome is burning.” He saw Webley opening his mouth to speak and made haste to anticipate what he imagined was going to be his objection. “No doubt,” he said, “you think you can make good the loss with phosphate rocks. But what’ll you do when the deposits are exhausted?” He poked Everard in the shirt front. “What then? Only two hundred years and they’ll be finished. You think we’re being progressive because we’re living on our capital. Phosphates, coal, petroleum, nitre – squander them all. That’s your policy. And meanwhile you go round trying to make our flesh creep with talk about revolutions.”
English author Aldous Huxley (“Brave New World”) came from a family steeped in biology and incorporated biological themes in his work.

According to Wikipedia, The character Everard Webley is a charismatic fascist-like figure. Lord Edward Tantamount is an amateur biologist.

Leave a Reply

Please log in using one of these methods to post your comment: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s