Pyrolysis is the “only viable, sustainable solution” to the River Wye pollution crisis

Greentech entrepreneur highlights potential of biochar to prevent phosphorous run-off

A technology pioneered by the ancient Greeks has been hailed as the only effective solution to a very twenty-first century problem – the threat to the River Wye’s unique eco-systems. Pyrolysis – the combustion of organic matter in the absence of oxygen – transforms poultry waste into biochar, a stable, slow-release fertilizer that can be spread safely on farmland without causing run-off.  

“Existing approaches to the disposal of poultry litter are simply not fit-for-purpose – and have had a devastating impact on the local environment,” said Giles Welch, the entrepreneur behind Greentech firm Onnu. “Land spreading is responsible for the disastrous run-offs, incineration releases carbon into the atmosphere, while Anaerobic Digestion (AD) is expensive, with complex transportation needs – and doesn’t address the basic issue of phosphorous entering our river systems. Pyrolysis is the only viable, sustainable solution to the problems created by waste biomass like poultry litter.”  

Pyrolysis is a self-sustaining process that uses the energy in the poultry litter to dry it and heat the resulting feedstock until it decomposes into biochar. The process also locks all the carbon contained in the poultry litter into the biochar: this therefore serves as a carbon sink and qualifies for carbon credits. In most cases, more energy is created than is needed for the pyrolysis process: this surplus can then be provided as a green energy source to decarbonise other business operations.  

“The poultry litter has to end up somewhere other than in our rivers so, for the farmer, pyrolysis makes a virtue of a necessity,” explained Welch. “The phosphorous is captured in a solid biochar that can safely be spread on land without causing run-off, or emitting greenhouse gases like Nitrous Oxide. The biochar also captures carbon that would otherwise be released into the atmosphere.”

Biochar produced from poultry litter is only 5% of the weight of the original sludge, greatly reducing requirements for storage, transportation, and land application. As with fertilizer derived from poultry litter, biochar delivers key nutrients (including phosphorus) to the soil, but the release is slower, eliminating the threat of run-off and ecological damage, and allowing transportation to where it is needed most.

“We are being forced to choose between a unique ecosystem in an area of outstanding natural beauty and an industry that contributes a billion pounds to the River Wye economy and supports ten thousand jobs – why shouldn’t we aspire to have both?” asked Welch. “The net result of pyrolysis is a win-win: it’s great for the poultry farmer - and a huge positive for the environment.”  

About Onnu  

Onnu’s ambition is to facilitate the transition to a Net Zero economy by realising the potential of biochar to tackle the world’s toughest decarbonisation challenges. It will achieve this by creating a pyrolysis-based Greentech industry that ensures waste biomass is processed in ways that are affordable, readily available – and acceptable to the public and the regulatory authorities. In the pursuit of that ambition, Onnu aims to build 100 pyrolysis-based energy hubs over the next decade.

Contact

Iain Halpin - Head of Communications

iain.halpin@onnu.com

‍