Researchers are searching for a sustainable, environmentally-friendlier source of soil conditioner and crop fertilizer that could reduce costs to farmers -  all from renewable energy waste.

A collaborative project between Stopford Energy and Environment Limited, the James Hutton Institute, Aqua Enviro Limited and the University of Lancaster builds upon Stopford research looking at using a mixture of digestates, derived from anaerobic digestion, and ash, from burnt biomass, as an alternative to existing crop fertilizers.

Fertilizers, such as phosphorous and nitrate-based products, are commonly produced using energy-intensive methods involving the use of oil and gas. In addition phosphate-based fertilizer relies on the mining of phosphate, a finite and unsustainable resource, and a production process using various toxic chemicals.

A successful digestate-ash fertilizer could reduce reliance on fossil fuels and provide income to biomass and anerobic digestion operators. These forms of renewable energy might be up 15 percent of UK energy by 2020, though primarily due to higher costs and taxpayer subsidies, so more options would be better for the public and appealing for investors, since ash is currently expensively dumped at landfill.

Dr. Ben Herbert, Director of Research and Environment at Stopford Energy and Environment, said, “this research has the potential to transform the long-term economic viability of the bio-energy sector by turning by-products, which at present have limited commercial value, into saleable land conditioners for use in agriculture.” 

 Previous studies by Stopford Energy&Environment have shown that biomass-ash and digestate can be useful nutrient sources for crops in conditions low in nutrients. Ash is rich in micro and macro-nutrients. Anerobic digestate is a rich source of trace metals and nitrogen. 

Professor Kirk Semple from the Lancaster Environment Centre, said, “The aim of this research is to modify the by-products from anaerobic digestion and biomass energy plants to create a new, safe and sustainable source of nutrients for agriculture. This would reduce pressure on natural resources and develop a new market for problematic by-products of the bio-energy industry.

“The project represents an excellent collaboration between academia and industry to address some of the major challenges facing food and energy security. Although the project is based here in the UK, we believe there is exciting potential to produce a sustainable alternative to existing fertilizer use across the globe.”

The three-year project has received £856,484 funding from the Natural Environment Research Council Research and consist of field trials and lab work at Lancaster University.