Phosphorus Recycling

In the 20th century the three nutrients nitrogen, phosphorus and potassium have enabled agriculture to increase its productivity. This is usually represented by three numbers (for example, 19-12-5). We obtain nitrogen from the air, but we must mine phosphorus and potassium. The world has enough potassium to last several centuries. But phosphorus supplies may start running out in the near future.

The reserves of phosphorus aren't very evenly distributed. The U.S. is the world’s second-largest producer of phosphorus (after China), at 19 percent of the total, but 65 percent of that amount comes from a single source: pit mines near Tampa, which may not last more than a few decades. Meanwhile nearly 40 percent of global reserves are controlled by a single country, Morocco, sometimes referred to as the “Saudi Arabia of phosphorus.” Although Morocco is a stable, friendly nation, the imbalance makes phosphorus a geostrategic ticking time bomb.

The conventional phosphorus fertilizer production cycle is an energy-intensive process that releases greenhouse gases into the environment at every stage:

• mining of phosphorus ore, 
• concentration into phosphate rock, 
• transportation from mine sites around the world, 
• centralized manufacture into fertilizer, and 
• transportation to customers.

Each year more than 100 million tons of phosphate rock are mined and processed into fertilizer. Over time this fertilizer enters the ecosystem as waste and agricultural runoff, leading to excessive nutrient levels, or a condition known as eutrophication. Eutrophication causes excessive algae growth in lakes, streams and oceans which depletes the oxygen supply in the water that is necessary to support aquatic life.

A Solution

Our food contains the nutrients taken up by plants which we expel back in to the environment by our digestive systems and toilets. Whilst traditional sources from rocks are being depleted there is quite a lot of it in sewage treatment plants. Thames Water has installed new technology from Ostara in its Slough plant. It strips phosphorous from sewage water producing around 120 tonnes of fertiliser each year. The end result is a produce called Crystal Green.    

1. Waste water streams from municipal and industrial treatment facilities, rich in phosphorus and nitrogen, provide essential nutrient streams for the recovery technology.
2. Fertilizer Production: Rather than view sewage as waste, the solution transforms waste water streams into a renewable resource, creating a planet-friendly fertilizer and saving millions in plant maintenance costs.
3. Agriculture: Crystal Green is the world's first fertilizer made from a local, renewable resource. Suitable in horticultural, turf and agriculture, its slow-release formulation results in considerably less nutrient leaching and runoff.
4. Food Consumption: The recovery technology is the ideal solution for growing urban areas where nutrient discharge limits become a challenge to meet in the face of rising volumes of waste water and associated costs.
5. Environmental Impact: By reclaiming the nutrients in their municipal, industrial and livestock waste waters, most countries could actually become phosphorus-independent – and help protect water resources from these otherwise polluting nutrients.

Useful links for more information:

• http://www.scientificamerican.com/article.cfm?id=phosphorus-a-looming-crisis
• http://www.crystalgreen.com/content/sustainability
• http://www.ostara.com/sustainability
• http://www.ostara.com/technology