Recycling Locally Produced Bio-Wastes to Ensure Affordability and Availability of Innovative Bio-Based Fertilisers

Project Information

ReLeaf

Grant agreement ID: 101156998

DOI

10.3030/101156998

EC signature date 2 May 2024

Start date 1 June 2024

End date 31 May 2028

Funded under

• Food, Bioeconomy Natural Resources, Agriculture and Environment

Total cost

€ 7 814 748,75

EU contribution

€ 6 504 027,75

Coordinated by

ACONDICIONAMIENTO TARRASENSE ASSOCIACION
Spain

Periodic Reporting for period 1 - ReLeaf (Recycling Locally Produced Bio-Wastes to Ensure Affordability and Availability of Innovative Bio-Based Fertilisers)

Reporting period: 2024-06-01 to 2025-05-31

Summary of the context and overall objectives of the project

The use of synthetic fertilisers is a regular farming practice in most EU countries. Although the production of mineral fertilisers based on non-renewable sources (fossil energy and rock deposits for N and P, respectively) have enabled the access to sufficient food for the world’s growing global population, the current dependency of EU agriculture on fossil-based mineral fertiliser can lead to a serious threat to future food security.

ReLEAF (Recycling Lovally Produced Bio-Wastes to Ensure Affordability and Availability of Innovative Bio-Based Fertilisers) seeks to overcome challenges related to production of sustainable, precisely applicable, and safe bio-based fertilisers (BBFs). To this end, a suite of 8 technologies that extract nitrogen, phosphorous, biostimulant, and biopolymer ingredients from waste feedstocks, will be demonstrated at TRL 6 – 7 to enable the formulation and production of novel controlled release BBFs (up to 2 tonnes of compliant controlled-release BBFs by the end of the project).

Newly formulated BBFs will be tested in fields in 4 different climate conditions (Mediterranean, Atlantic, Continental, and sub-Alpine) to enable the accelerated uptake of BBFs. The extensive involvement of feedstock owners, industrial partners with existing supply chains, innovative SMEs, and a second-tier farming cooperative will ensure exploitation of the project solutions. ReLEAF will thus establish circular value chains with the potential to increase nutrient recycling from the selected bio-waste streams by up to 70%, reduce nutrient losses by up to 60%, and prevent the pollution of microplastics in soil.

The project is expected to contribute the following impacts:

- Enhance availability of affordable and sustainable fertilizer in the EU by producing and commercializing up to 100 tonne/y of novel BBFs by 2035.
- Decrease of 30% of fertilisers use by 2035 with the use of precision BBFs and effects of biopolymers to increase bioavailability, reduce nutrient losses, and tailor formulations to each growth stage.
- Engagement of >1000 stakeholders within the broader ReLEAF network by 2035, fostering the creation of new value chains that allows to close nutrient cycles
- Reduction of 25% in nutrient losses using ReLEAF controlled-release BBFs by 2035

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

During the first 12 months, ReLEAF carried out several complementary activities focused on the recovery of ingredients from widely available bio-wastes (i.e. sewage sludge, fish processing wastes and wastewaters, agri-food residues, and HORECA wastes) for the formulation and production of controlled-release bio-based fertilisers (BBFs) that can competitive in the EU fertilisers market, partially replacing synthetic fertilisers:

1. Recovery of nutrients: ReLEAF optimised the recovery of nutrients from sewage sludge liquid fraction through: (1) selective recovery of NH4 by using membrane-assisted stripping at moderate pH conditions (pH 10) and (2) simultaneous struvite and K-struvite crystallization for the recovery of N, P, and K.
2. Production of biostimulants: Microbial biomasses and chemical biostimulants (as humic and fulvic acids) have been produced from ReLEAF bio-wastes. In addition, solid state fermentation of HORECA wastes and agri-food residues resulted in a fermented solid with biostimulant properties.
3. Production of biopolymers: PHA have been produced by using agri-food wastes and a mixture of agri-food wastes with nutrient exhausted sewage sludge fostering cascade use of feedstocks. In addition, non-thermal pre-treatments allowed the recovery of collagen and keratin from fish wastes using less water and reagents.
4. Formulation of controlled-release bio-based fertilisers: Preliminar formulations of pelletised microbial biostimulant and microencapsulated BBFs have been developed and are currently being assessed in mini pot tests.
5. Formulation of nutrient-functionalised horticulture elements: Planting pots characteristics have been agreed with end-users and the mold is under design. In addition, the first batch of mulching film has been produced by using a blend containing PHA and other certified soil-biodegradable biopolymers.
6. Safety and Regulations: BBF production and use safety parameters were preliminary assessed (results can be found in D5.1) according to bibliography and ECHA recommendations. European and national regulations concerning Fertilising Products were summarized, and a preliminar assessment of ReLEAF ingredients were assessed (D1.1). In addition, a list of safety parameters to be analysed for each BBF was developed and distributed to ingredient producers.
7. Sustainability: The Environmental and Social Life Cycle Assessment and Life Cycle Costing framework was stablished, and a common questionnaire was developed. In addition, a benchmark with existing literature was performed through systematic literature review and results and conclusions can be found in D5.1.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

After 12 months of project execution, ReLEAF partners were able to develop and optimise laboratory scale processes for increasing the nutrient recovery and producing biopolymers from bio-waste streams, suitable for being used for the formulation of controlled-release BBFs.

The following points summarises how ReLEAF was able to progress beyond the state of the art:
- Sewage sludge was able to be fully valorised through the cascade use of feedstocks and differential treatment of solid and liquid fractions for the recovery of nutrients, chemical biostimulants, and production of biopolymers as PHA.
- 55 microbial strains were assessed for being growth in fish processing wastewaters doped with molasses (from industrial by-products), where 15 were selected for being tested at mini-post tests. 5 novel plant growth promoting bacteria were identified as promising ones according to the production of phytohormones, plant growth, and phosphorus solubilisation potential, among others.
- Agri-food residues and HORECA waste have been valorised as fermented solid containing plant growth promoting microorganisms (i.e. Trocoderma Harzianum) and phytohormones (i.e. indo-3-acetic acid) as biostimulant.
- Non-thermal pre-treatments were able to increase up to 5% the production of biopolymers by using fish wastes, while reducing up to 50% the use of chemicals and water.