Phosphorus is an essential building block of life. It is an irreplaceable part of modern agriculture, as there is no substitute for its use in animal feed and fertiliser. The current situation, involving waste and losses at every step of the phosphorus life cycle, contributes to concerns about future supplies and water and soil pollution, both in the EU and worldwide. With efficient production and use, as well as recycling and minimisation of waste, major strides could be made towards the sustainable use of phosphorus, thereby setting the world on a path towards resource efficiency and ensuring that reserves are still available for the generations to come.
Phosphorus resources are relatively abundant globally and reserves are significant. However, there are several factors that together mean that for the EU, the issues affecting the security of supply should be monitored. Firstly, within the EU, there are only small reserves of phosphate bearing rock. Secondly, there has been recent price volatility - in 2008, prices of phosphorus rock rose by 700% in a little over a year, contributing to increases in fertiliser prices. Thirdly, there is little scope to switch from less important uses of phosphorus, as the essential use of feed and fertiliser already consumes around 90% of the total mined resource. Improving the use of recycled phosphorus in the EU and worldwide would help safeguard the supply of this fundamental raw material and encourage a more even distribution of phosphorus at both regional and global level. Economically, diversifying the supply of phosphate to the EU businesses that depend on it would improve their resilience faced with any future price instability and other trends that might aggravate their import dependency.
In addition, the environmental and resource use benefits of increasing efficiency and reducing losses would be significant. The current use of phosphorus is inefficient at many stages of the life cycle, causing problematic water pollution and the waste of a wide range of associated resources. Contaminants such as cadmium and uranium in the raw material may also cause health and environmental problems. Independently of the total volume of mined phosphate available and the security of supply aspects, these benefits alone would justify action being taken to use and recycle phosphorus more efficiently. The actions taken to improve the efficiency of phosphorus use and recycling would have a wide range of other advantages – better soil management would have climate and biodiversity benefits, for example.
The supply of phosphorus
Current production of phosphate rock is concentrated in a limited number of countries. None are in the EU, with the exception of Finland where there is a small amount of production. (első 2 mondat)
For phosphate fertilisers, the EU is currently highly dependent on import of phosphate rock mined outside of the EU (more than 90% of the phosphate fertilisers used in the EU are imported, mainly from Morocco, Tunisia and Russia). This while domestic waste contains large amounts of phosphorus, which – if recycled in line with a circular economy model – could potentially cover about 20-30% of EU's demand of phosphate fertilisers.
The 2008 price spike
From 2007-8 the price of phosphate rock went up by over 700% in a fourteen-month period. In 2008, China imposed an export duty of 110-120% on phosphate rock, which was then reduced in several stages to the level of 35%, which is still applied today. Global operating capacity for phosphoric acid peaked at close to the maximum possible. This high price attracted considerable interest from the press and stakeholders.
ENVIRONMENTAL IMPACTS THROUGHOUT THE PHOSPHORUS CYCLE
Sustainable use of phosphorus goes wider than the issues around that one element. When phosphorus is wasted, the energy, water and other resources contributing to its production cycle are wasted along with it. In addition, phosphorus ending up in water bodies causes its own environmental problems, notably in the shape of eutrophication. Excess phosphorus, mainly from intensive agriculture and horticulture is a major cause of eutrophication of lakes and rivers. Soil erosion can carry significant amounts of soil-bound phosphorus into surface water.
The contaminant present in phosphate fertilisers (unless removed by decadmiation technologies) that is currently of most concern is cadmium, although other heavy metals may also need monitoring. Once present in soil, cadmium cannot be easily removed, but can migrate and accumulate in plants. Certain plants (sunflowers, colza, tobacco, etc.) tend to accumulate larger amounts of cadmium.
Soil and groundwater contamination by uranium – mainly from natural background presence, but possibly exacerbated by the presence of uranium in phosphate fertilisers – has been reported in areas with sandy soil in Germany, with consequences for the processing of drinking water in some cases. This contamination could result in extra precautions and costs in the areas of drinking water and agricultural production. (Rock phosphates and P fertilizers as sources of U contamination in agricultural soils, Kratz and Schnug, 2006)
More efficient use and conservation in agriculture
Efficient crop production means having enough plant-available phosphorus in the soil (the critical level) to meet the requirements of the plant throughout its development, but no more.
Better use of manure
During the past decade, the implementation of the Nitrates Directive has been a driver for much better manure management. There has been a surge of interest in manure processing and in transforming the phosphorus-rich solid part of processed manure into a saleable product outside its area of production, where fields are often saturated with nutrients. Although slurry manure starts off with a water content of about 95%, processing can reduce the volume of the solid fraction to about 30% of the original slurry manure, but a number of obstacles to exporting processed manure such as cost (transport, energy) – still remain. Acceptability by receiving farms is also still an issue.
Potential gains related to prevention and recovery of food waste
Any reduction of food waste at the production and consumption stages would reduce the need to introduce new phosphorus into the system from the rock resource. The situation around food waste has been exhaustively studied. Every person in the EU wastes on average 180 kg of food every year.
As well as preventing food waste, we could also make better use of the food waste that is generated. Currently, large quantities of food waste and biodegradable waste in general are incinerated, and often the phosphorus in the ash is not reused.
Using biodegradable waste in the form of compost, digestate or ashes from green or kitchen waste would recycle significant quantities of phosphorus along with other nutrients.
In addition to this, there are a number of waste streams from agriculture and by-products from food production that could recycle significant quantities of phosphorus, if properly managed. For some of these resources, public health problems and the actions needed to tackle them have made this process less efficient in recent years. One notable example is bone given that phosphorus is mainly concentrated in the bone structure. Although some meat and bone meal is incinerated and the ashes are used either as fertiliser, directly as a form of soil improver, or in phosphorus production , much of the phosphorus is simply wasted.
Waste water treatment
Waste after human consumption is inevitable, but there are a number of technologies that enable recovery of the phosphorus from waste water treatment plants. These techniques have developed significantly over recent years, with the setting up of several pilot projects and now commercial scale operations in western and northern Europe.
There are alternative techniques to extract phosphorus. These include removing of phosphorus waste water in the form of struvite, incinerating sewage sludge and using the ashes, and applying the sewage sludge directly onto fields after appropriate treatment. In all cases, the agronomic quality of the product is crucial to ensuring that the phosphorus is actually available and being taken up by crops.
Reference: COM(2013) 517 final, Consultative Communication on the Sustainable Use of Phosphorus