By 2050, the world will require 60 percent more food produce as a result of rapid population growth and changing diets: as incomes rise demand for dairy products and meat increases. Globally, demand for phosphate as a fertilizer nutrient will rise from 43.8 million tons per annum in 2015 to 52.9 million tons in 2030. Currently, Asia accounts for almost 60% of the world’s total nutrient use, with China and India consuming around 55% and 29% of Asia’s total consumption of fertilizer. Over the next five years, Asia’s consumption of fertilizer will increase by around 6% due to changing and interconnected trends including economic and population growth and increased demand for food.
Phosphorous’ role in food security
In Europe, the sustainable supply of phosphorous was identified in both the Communication Towards a Circular Economy: A Zero Waste Programme for Europe and the 2011 Roadmap to a Resource Efficient Europe as an important factor affecting sustainability and long-term global food security. The mineral is an essential building block of life and is an irreplaceable part of modern agricultural production in its use as an animal feed and fertilizer. Despite phosphorous resources being abundant globally there are three issues impacting availability of supply, both in the EU and globally.
First, there are only small reserves of phosphate-bearing rocks in the EU: the production of phosphate rock is concentrated in a limited number of countries none of which are located in the EU, with the exception of Finland, which produces a small amount of production. It is estimated that 90% of the world’s phosphorous reserves are located in just five countries: China, Morocco, South Africa, Jordan and the United States. This has led to the EU importing 92% of its phosphorous. Second, there has been price volatility: in 2008 prices of phosphorous rose by 700% in just over a year resulting in increasing fertilizer and food prices and third, there is little ability to reduce non-essential use of phosphorous: its use in animal feed and fertilizer already consumes around 90% of the total mined resource. Improving the use of recycled phosphorous in the EU and globally would help safeguard the supply of this critical raw material.
Phosphorus recovery in the UK
In the UK, Thames Water, which is the largest water and sewage company in the UK, has partnered with Ostra Nutrient Recovery Technologies to launch the UK’s first nutrient recover facility at Slough Sewage Treatment Works producing commercial fertilizer from wastewater. Phosphorous and nitrogen concentrated in the facility’s wastewater can form a concrete-like substance called struvite which coats pipes and valves, reducing the plant’s efficiency in treating wastewater: an energy-intensive process resulting in costly maintenance. The plant’s nutrient recovery system addresses these issues by converting the struvite into pellets of high-grade fertilizer. The plant is expected to produce 150 tons of fertilizer pellets a year for sale to crop-growers as well as gardeners. Economically, the plant will also save £200,000 per annum by avoiding operation and maintenance costs.
The take-out
Producing fertilizer from sewage increases the efficiency of wastewater treatment plants by reducing maintenance costs, increases the amount of fertilizer available for food production, and provides an additional revenue-stream for utilities.