Thames Water pioneers sustainable fertiliser production

The first reactor in Europe which can create phosphorus-based fertiliser from sewage has been opened by Thames Water.

A total of 138,000 tonnes of phosphate fertiliser is used by the UK each year, all of it imported from abroad – usually from the mining of non-renewable reserves.

The price of phosphorus has also increased by 500 per cent since 2007 and it is hoped the reactor can provide a cheaper and more environmentally-friendly alternative to mining.

The £2 million nutrient-recovery reactor at Slough sewage works will produce 150 tonnes a year of sanitised fertiliser.

Thames Water says it intends to assess the suitability of installing the technology at its other plants.

Peter Melchett, policy director at 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.”

The fertiliser produced from the facility is also cleaner than conventional mined phosphate as it contains less heavy metals and its formation produces no radio-active by-products.

The reactor works by converting struvite, which can clog up pipes if left unchecked, into crystalline fertiliser pellets.

Piers Clark, commercial director for Thames Water, described the technology as “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,” he said.  

“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.”