ADBA Expo March 2022 BANNER AD.
Phosphorus Nutrient Recycling Role for Anaerobic Digestion

The Phosphorus Crisis & Nutrient Recycling – A Vital Role for Anaerobic Digestion

Many experts have been warning us all that current farming practices are not sustainable in the long-term, and a looming crisis exists because all modern agriculture relies on a cheap supply of phosphorus.  Today that comes from mined phosphorous. Although phosphorous can be mined at the present time, those reserves are running out.

This is explained in our introductory video below. We suggest that you watch the video and then scroll down to read the further information we have found on this subject.

Here are just two, of many articles online, which each point out different aspects of the coming phosphorous crisis in agriculture:

Declining Phosphorus Supplies

Long before a global phosphorus crisis occurs, declining supplies may present a windfall for water quality and sustainable agriculture. As you point out, declining phosphorus supplies will encourage efficient recycling of phosphorus-rich livestock manure. via Phosphorus decline could be good for water supplies

Rising Phosphorous Demand

Is it the biggest looming crisis that you have never heard of … We have to remember that the world's population is growing steadily, and so demand for phosphorus is growing every year.” As Dr Sella explains, phosphorus is essential for life. via The world's insatiable hunger for phosphorus

Phosphorous from Agricultural Fertiliser is Causing Damaging Lake Eutrophication

The following article explains how eutrophication due to the intensive use of chemical agricultural fertilisers containing a high phosphorous content, is causing problems, which can be at least partially averted putting natural processes, such as anaerobic digestion to work in new ways:

In the Chesapeake (US) watershed, excess nutrients from animal operations are a significant source of pollution. More than 40 percent of the nitrogen and phosphorus introduced into the bay come from agriculture, and half of these nutrients come from animal manure.

The good news is that by deploying new and evolving technologies such as gasification systems and anaerobic digesters, farmers can convert animal manure into much-needed bio-gas and electricity while simultaneously reducing nutrient loads that degrade water quality.

And by growing bio-energy crops like perennial grasses and fast-growing trees, which don't require annual tilling of the soil or the application of fertilizer, farmers can significantly reduce the amount of sediment and nutrients that might otherwise end up in streams, lakes and estuaries that feed into the bay.

Farm energy programs, such as those authorized in the Energy Title of the Farm Bill, help farmers put these technologies [for example anaerobic digestion] into place and can be a critical tool in turning liabilities into high-value assets.

They offset costs to repower biorefineries [i.e. biogas plants] with biomass feedstocks and low-carbon fuels; construct solar, wind and bio-gas electricity generation systems; and retrofit equipment, barns and other farm infrastructure to improve energy efficiency.

Collectively, these projects unlock hundreds of millions of dollars in private investment that in turn diversify our economy, create jobs and generate new streams of revenue.

And in an era of fiscal contraction for environmental programs, they can be important new vehicles for improving soil, water and air quality and wildlife habitat. via Farm energy programs do double duty

Put together the risks from declining supplies and rising demand, with the pollution of watercourses and lakes from uetrophication, and to describe this as a crisis is not an exaggeration.

Our Opinion

Once again the anaerobic digestion process can be the key to solving part of this problem, and to explain our vision of how that can be achieved we produced the video which is provided at the top of this page, titled

There's a farming crisis no one is talking about: The world is running out of phosphorus, an essential element that's a key component of DNA and the basis of cellular communication.

Anaerobic digestion can be used to capture the phosphorus in manure, and it can then be sold as an additional revenue maker by anaerobic digestion plant owners. Just how that can be achieved is described in the following (final article on this page) as explained below:

Why Phosphorus Nutrient Recycling Will Become a Vital Role for Anaerobic Digestion

Phosphorus Nutrient Recycling Role for Anaerobic DigestionPhosphorus is not about to disappear, but geologists tell us that it is a finite resource.

Unfortunately, at the moment it is much cheaper to excavate phosphate rock than to separate phosphorus from groundwater.

There seems to be just one source for some 77% of the world’s phosphate rock reserves – in Morocco.

The next largest producer is China with around 6%.

So, Phosphorus seems to be the resource that will limit our ability to feed mankind in the future.

Something must be done to enable phosphorus recycling for its re-use in fertiliser products.

Importation of mined phosphorus could be replaced by recycling animal manure.

The only thing that is needed is an economical way of concentrating the phosphorus in manure, and sewage, and transporting it to where it is needed as a raw material for fertiliser production.

At its most basic, it’s as simple as that.

Now lets look at Chickens!

Far from there being too little phosphorus from chicken litter, the opposite is true.

The problem with chickens is that research suggests that the more chickens there are per hectare, the higher the concentration of phosphate in the soil.

This means that chicken litter cannot be applied on nearby fields – instead it must be transported to other locations. [To avoid a damaging build-up.]

Although the litter is relatively dry, particularly when compared to cow slurry, the cost of transportation is excessively high.

Anaerobic Digestion experts at Ductor Oy have a solution for both general manures, and chicken litter.

They take manures such as chicken litter and convert them into renewable energy as well as a nitrogen fertiliser, ammonium sulphate, and most importantly, a solid phosphorus fertiliser. [Using a special process alleid with traditional anaerobic digestion.]

They use a special fermentation process in which gets microbes to convert the organic nitrogen into ammonium.

That ammonium is then easily removed from the manure using conventional stripping equipment.

This way the unsuitability of chicken litter as anaerobic digestion substrate is eliminated.

This means that chicken litter with suitable nitrogen levels can now enter the biogas digestion process, and around 20% of the organic matter will turn into biogas.

This in has the welcome effect of concentrating phosphorus in the digested material.

There is then a solid-liquid separation process and the digestate is dried, in a super-heated steam dryer to form up to 80% dry matter.

This can be pelleted for more convenient spreading.

This result is a phosphorus fertiliser that can be transported and stored economically.

In addition, the nitrogen removed from the litter is turned into ammonium sulphate, a nitrogen fertiliser.

There is no other comparably simple way to achieve Phosphorus Nutrient Recycling, so it is predicted that this will become a vital role for Anaerobic Digestion.

This article and the video at the top of this page are based on an article written by Ilkka Virkajärvi, CTO Ductor

Read more about Ductor's Anaerobic Digestion of Chicken Litter (Manure) here.

Tags: , , , , , , , ,
Previous Post
ADBA's Chris Huhne in Bio-Bug  CC BY-NC-ND by DECCgovuk

Renewable Transport Fuel Obligation (RTFO) Update 5 March 2018

Next Post
anaerobic digestion of biomass illustrated using the title graphic.

7 Tips to Assess If the Anaerobic Digestion of Biomass Will Benefit a Food Company


  1. Reply

    The Scottish Waste Aware Campaign in the Western Isles is needing to devote a large part of their campaigns to educating residents to do the right thing and recycle their waste focused on getting the Reduce, Reuse, Recycle, message into the Community. We like to see this nutrient recycling having a big success.

    • BB
    • October 16, 2017

    Hey There. This is an extremely well written article.
    You seem to be well informed of the latest developments in AD tech.
    I will be sure to bookmark it, and return to read more. Thanking for the fascinating possibilities of phosphorus recycling. I’ll definitely come back.

    • KING of Kinnersley
    • October 18, 2017

    Hi, my name is King Kinnersley, and I am known online as the KING. Keep your cool man. Fertilizer won’t run-out. Trust me on that one.

  2. Reply

    Liked you video. Nice one! Ꭲhanks fօr expressing уoսr ideas. І would also like to say that videos are been ever evolving.
    Technology advances and enhancements havе served to push back old barriers.
    It is amazing what you plan in these articles.
    Adequate phosphorus is always an essential for farming to raise crops. You have many good ideas.
    Please tell your people that we sell Biogas Generator at Best Price in India.

    • E Hollis
    • October 28, 2017

    Hi, thanks I will subscribe for this website
    to get most up-to-date updates.
    Why is it that only very few people are
    talking about this? Phosphorus scarcity must
    be so important that it should be up there
    among issues like climate change.

  3. Reply

    There is definitely a lot to learn about this topic.
    I really like all the points you made, but don’t you think that more phosphorus sources will appear as time goes on and the price rises?

Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.