Thames Water has announced that a new sewage treatment plant in the South East will begin producing environmentally friendly fertiliser from human waste.

The facility, at Slough in Berkshire, houses Europe's first nutrient-recovery reactor that produces sanitised phosphorous-based fertiliser from waste water. Thames water said the water and waste content around Slough (coming from the Slough Trading Estate) are particularly well suited to making fertiliser.

The £2 million facility, built by a Vancouver-based company Ostara Nutrient Recovery, makes the phosphorous form into struvite in a controlled setting, before turning it into crystalline fertiliser pellets.

Struvite can be a problem in the waste treatment business – formation of struvite deposits (a rock-like scale that covers pipes) can block them completely if left unchecked. In addition to providing fertiliser for the farming industry, the new facility will reduce the need for chemical treatments to prevent struvite forming in pipes.

The UK uses 138,000 tonnes of phosphate fertiliser a year, all of it imported from abroad. Mined phosphorus in a non-renewable resource; reserves in countries like Morocco, the US and China, are set to be completely depleted in the next 100 years. According to the Soil Association, 'peak phosphorous' could occur as early as the mid-¬2030s, after which time the mineral will become increasingly scarce and expensive (prices of phosphorous fertiliser have already increased by 500 percent since 2007).

According to the manufacturers of the new fertiliser – marketed as Crystal Green – the product has a far smaller heavy metal content than mined phosphorous. Fertiliser is already produced from human waste in some areas of the world, where scarcity of water and other resources have made waste reduction and recycling a necessity.

Experts have said that, in addition to phosphorous, human waste could also be used to produce ammonium fertilisers.

In July, analysis by scientists at the University of Sheffield showed that the UK's available soil has just 100 seasons of nutrients left in it. Two Sheffield academics called for a paradigm in agriculture to reverse damage to this most precious resource. They recommended a large-scale shift towards organic growing techniques, cutting edge technologies and the development of wasteless systems to help UK agriculture flourish.

Professor Tony Ryan, of the University of Sheffield, said better waste recovery has a significant part to play in making agriculture more sustainable. He explained, "Phosphorous and nitrogen are limiting nutrients both of which are found in human waste [and] which scientists believe could be used more efficiently. People produce 1.5 tonnes of faeces and urine each year (400 kg of solid and 1100 litres of liquid); this could provide 20 kg of elemental PNK fertiliser and grow 200 kg of cereal. A human resource we cannot afford to waste anymore."

http://www.farming.co.uk/news/article/8682

Commenting on Wednesday, Peter Melchett, policy director at organic farming certifiers the Soil Association, said, "With the world's affordable mineable reserves of phosphorous set to start running out in the next 20 to 30 years, this new technology could offer a solution to securing global food supplies over the coming decades.

"Without fertilisation from phosphorous, wheat crop yields will fall by more than half. Meanwhile, as the planet's population is predicted to hit nine billion by 2050, demand for food will increase. Sustainable alternative sources of phosphorous, like this reactor at Slough sewage works, are vital if we are to keep pace with this demand."

Piers Clark, commercial director for Thames Water, was also highly supportive of the initiative. He said in a statement, "This is a classic win: win. We are producing eco-friendly steroids for plants, while also tackling the costly problem of struvite fouling up pipes at our works. The cash and carbon cost of digging phosphate out of the ground in a far-flung foreign clime then shipping it back to Britain makes no sense when compared to the local, sustainable process of our reactor in Slough. As we gain experience with this new technology, we intend to evaluate its suitability for installation at other Thames Water plants in the UK".