In the face of finite sources of conventional phosphorus, and highly energy-intensive and price-sensitive nitrogen, agriculture is challenged to maintain or increase food production and simultaneously reduce its carbon impact. Fertiliser prices are strongly influenced by the crude oil price, reflecting the energy intensity of the manufacturing process. Finite nutrient sources are being depleted, whilst nutrients are lost from the land through crop harvest. It is therefore necessary to identify alternative sources of nutrients which can be safely applied to crops to sustain food production which can be produced with lower carbon impacts, and less environmental damage.

The proliferation of the renewable energy sector, as a means of reducing carbon emissions, has resulted in the growth of biomass to energy schemes. Agricultural land is the "expected" sink for digestate in the UK according to government policy since these waste sources are nutrient-rich. However, a number of limitations restrict the use digestate: highly variable composition (both spatially and temporally); undesirable compounds and contaminants presence (excessive metals; plastics residues); lower nutrient content than in manufactured fertilisers (higher volumes applied); logistical constraints (spatial dispersion from source); temporal constraints (application limited to certain periods, thus need for interim storage); uncertainties of crop responses. These undesirable factors have resulted in it being a disposal cost to the AD operator (average £3.73/t in 2013). Ash is similarly plagued by inconsistent composition and other undesirable characteristics and so significant quantities are being disposed of in landfill. For both digestate and ash, their disposal means that nutrients are lost from the cycle, incurring high costs to the renewable energy industry. These limitations present a clear need for development of an alternative product or process which can present an attractive solution to both the bio-energy and agricultural sectors alike.

The overarching objective is to develop commercially viable, high quality, consistent, sustainable fertilisers from bioenergy residues. Four main considerations are central to understanding the behaviour of the feedstocks in making a product: nutrient retention, form, and stability of the nutrient during processing; and whether the nutrient will be supplemented by other sources to meet a specification. Considering the aforementioned statements, the overall aim will be achieved through the following:

(i) Physico-chemical characterisation of individual waste streams (ash and digestate) and putative fertiliser products, including the identification of other suitable wastes
(ii) Assessment of the effects of reaction conditions on nutrient availability and potentially toxic elements presence on the fertiliser product, especially to understand in detail nitrogen retention, Phosphorus speciation and availability and long term stability controlling factors.
(iii) Quantification of the impact of ash and digestate mixtures on plant growth and comparison against traditional inorganic fertilisers.
(iv) Identification of legislative requirements and commercial considerations of the putative fertiliser products for use in agriculture as factual alternatives to conventional fertiliser applications

Extensive testing on selected treatments and reaction conditions in the laboratory and plant growth in glasshouse trials will represent and step towards the applicability, commercialisation and viability of the formulated product in an agricultural setting. Benefits of such scenario are reduction in the dependence on phosphorus and nitrogen finite fertiliser resources, contribution to food security and compliance with waste hierarchy and resource recovery.

Technical Abstract:
This project seeks to formulate complete, (N:P:K) balanced, agricultural fertilisers by combining and processing bio-energy wastes; anaerobic digestate, and ash from thermal conversion of woody biomass. The project will focus on developing and testing products derived from these waste streams that will have an exact specification that offers superior performance to conventional manufactured fertiliser products. Sourcing nutrients from waste materials presents a more environmentally and geo- politically sustainable approach to conventional fertilisers sourced from finite sources of phosphorus, and highly energy-intensive and price-sensitive nitrogen. With primary productivity expected to increase up to 10% through application of these products, this project presents a considerable opportunity to enhance food security and human nutrition globally, whilst presenting a significant commercial opportunity for SEE as well as UK based bio-energy and agricultural supply chains."

Potential Impact:
Additional benefits to be derived from Innovate UK's funding will be job creation and enhanced UK earnings, particularly as the project is SME led and it will exploit a UK innovation and place it solidly as a UK technology. The technology will make the UK a leader in this field and it will create an opportunity for it to take advantage of the market opportunities expected in a rapidly developing sector. It would be unfortunate if this innovation were developed elsewhere. Ultimately, funding a project with these characteristics matches the remit of Innovate UK. As an SME the company is not in a position to support this research, and without financial support from Innovate UK it is not likely that the technology will be exploited for some years and until the current business has developed to the point where it could justify financing the whole of this work. The company's experience in protecting IP within earlier projects also shows the criticality of being able to sufficiently resource the R&D required and generate a new patent. With financial support from Innovate UK and by sharing the risks and project costs, it is expected that the team will be able to complete this work, which has the potential to create over £10m revenue within 5 years and increase staff recruited by more than 20 people. It is estimated that the technology will be worth £220m total in 10 years post launch. Innovate UK's support will also enable early technical understanding to be achieved, providing valuable input to the structuring of a patent. The work will be carried out by UK based staff, and it is its intention to use UK based sub-contractors. As a result, Innovate UK's funding will also protect jobs in the UK

This concept technology addresses a major challenge faced by UK & EU biomass energy operators, namely solid waste, for farmers it provides an improved quality alternative fertiliser, and for all parties it will be more cost effective. There is a significant global commercial opportunity for developing a formulated fertiliser from digestate, ash and other bioenergy wastes, if the team can verify its cost effectiveness and efficiency. Without Innovate UK's support then these expected benefits will not be realised for several years, if at all.