The biggest challenge in making phosphate supplies sustainable is that rock phosphate is a finite resource. Like coal it was created millions of years ago and is extracted from the ground in open cast mines. As it is an irreplaceable resource, mankind can only focus on improving the efficiency of the remaining supply.
The Phosphorus Futures website reports how inefficiency is a major problem for the phosphate users. It states, “Only one-fifth of the phosphate mined specifically for food production ends up in the food we eat globally. Four-fifths of the phosphorus is lost or wasted during mining and processing, fertilizer production and distribution, fertilizer application on farms, food production and trade, right through to the dinner table.”
So, what can phosphate suppliers and users do to preserve the remaining sources of phosphate? What are mankind’s goals and efforts for making phosphate use more ‘sustainable’?
1.Improved fertilizer efficiency.
For many years, the agricultural industry has focused on improving fertilizer so that less product is needed for the same amount of food production.
As the Fertilizer Institute notes, “Farmers’ use of fertilizers is more efficient than it has ever been in history. Corn alone accounts for half of total U.S. fertilizer use, and when compared to 1980, U.S. farmers have more than doubled corn production. They also use 45 percent less nitrogen and 59 percent less phosphate to grow one bushel of corn than they did in 1980.”
However, the USA has only the third largest agricultural economy in the world. Developing economies must also make use of improved agriproducts and application methods if phosphate supplies are to last.
As a recent report by MiT notes, “…northern Chinese farmers use about 92 kg of phosphorus fertilizer per acre, of which only 39 kg are removed as crops. This means 53 kg, fully 58% of phosphorus, is not utilized and ultimately lost into the environment. As China is the largest phosphorus consumer in the world, with 5.2 Mt consumed in 2009 alone, reducing the country's phosphorus waste by even half would save the world over 1.5 Mt of phosphorus (3.45 Mt phosphate) per year.”
2.Phosphorus recovery
Recent legislation passed in Germany is set to make the country the “first EU member state to legislate to make phosphorus recycling from sewage sludge obligatory.”
The new law, translated as ‘MiTOrder for New Organisation of Sewage Sludge Valorisation’, was approved by the Federal Parliament 24th May 2017. It is intended to modify Germany’s legislation on sewage sludge management with two main objectives. The first is to ban land application of biosolids for larger sewage works, as well as requiring phosphorus recovery. While the second is to tighten quality requirements and contaminant limits for biosolids applied to land.
According to the phosphorus experts at Scope, the voice piece for the EU funded ‘European Sustainable Phosphorus Platform (ESPP), the new law will, “require phosphorus recovery if sewage sludge contains more than 2% phosphorus, such that either 50% of the phosphorus is recovered or such that the concentration is reduced to < 2% P, within either 12 or 15 years (works of > 100 000 or >50 000 p.e.). The phosphorus recovery can either be directly from the sewage sludge, or after thermal treatment of the sludge, or could be installed upstream in the sewage works, subject to achieving the required final recovery objectives.”
At present, around 60% of German sewage sludge is processed through larger sewage works, where phosphorus recovery will be obligatory. The law hopes to make better use of this resource, as currently just under 30% of German sewage sludge is used in agriculture.
3.Improved crop varieties and new phosphate sources
A research team from Arizona State University recently conducted a thorough review of phosphorus reserves and examined the varied proposals to extended phosphate use and limit waste.
Publishing their report ‘Sustainability Challenges of Phosphorus and Food: Solutions from Closing the Human Phosphorus Cycle’ in the scientific journal Biosciences, the team note the possibility of, “bioengineering crop strains that require less P for the same crop production or that more efficiently take up P from soils.”
4.Targeted Fertilizer application and limiting phosphorus run-off
Legislation has also been passed that attempts to encourage responsible use of phosphates by lowering agriproduct phosphate waste and limiting run-off from farmland. The legislation was established by the New Zealand government in November 2015, as Global Meat News reported, “Increased environmental regulation will have a significant impact on New Zealand’s sheep and beef farmers as well as their dairy counterparts.”
The law changed focused on ways to limit run-off from both arable and livestock farms, by methods that included, “maintaining riparian buffer-strips, targeted fertilizer application, careful cultivation, and methods to reduce soil erosion.”
5.Improved global management of phosphate supply
Some phosphate experts believe that phosphorus is such a scarce, and yet vital resource that the global supply should be managed better. They even propose a global body should regulate the industry and ensure that waste is minimised and phosphate supplies maintained.
One such proponent is Dr Dana Cordell, Research Principal at the Institute for Sustainable Futures, at the University of Technology Sydney, who writes, “Despite being one of the world’s most critical resources, there are no international organisations like the UN taking responsibility for phosphorus security in the long term. There is no independent, comprehensive and transparent data on the world’s remaining phosphate rock and trade. The US Geological Survey collates data provided directly by companies and countries as a public service, with no way of verifying the source, assumptions and authenticity of the data.”
While it is difficult to explain the complexity of phosphate's environmental impact in these few lines, it is clear that the phosphate industry has its work cut out to lessen its environmental impact.
As a vital resource helping to feed the world, phosphate suppliers are unsung heroes. As extractors and users of a finite resource, phosphate suppliers are part of mankind’s unsustainable existence. Add to this the thousands of phosphate suppliers that operate all over the planet; then coordinating a cohesive effort to make phosphate ‘greener’ becomes a herculean task.
As Dr Cordell notes, “The management of phosphorus is fragmented between many different sectors – from the mining and fertilizer sector where phosphorus is a globally-traded commodity, through to the sanitation sector where phosphorus is a pollutant, wastewater indicator and in some cases a resource to be recovered.”
Any chemical product that can be both a positive and a negative influence needs to be both looked after and watched carefully.
If you are interested in rock phosphate, monocalcium phosphate, STPP or other phosphorus raw materials then please take a look at the AG CHEMI GROUP product catalogue.
Photo credit: CriticalInvestor
