New fertilisers and bio-stimulants by making a sustainable use of organic waste

• NEIKER technology centre is participating in the European FERTILWASTES initiative with the challenge of developing new techniques that will place value on organic waste
• Micro-algae will have a leading role in this circular bio-economy project: they will help generate innovative products with value in agriculture

Usage or recovery of organic waste is essential in order to comply with the circular economy policies established by the main regional and European agencies as well as to prevent impacting the environment and reaching a more sustainable agriculture. However, current technologies that allows for industrial scale recovery of these materials are not 100% efficient and generate waste that must also be recovered.

Currently, waste generated based on these techniques (known as co-products) are mainly used as fertilisers; however, an extensive use of these is limited for different reasons.

“These are chemically complex materials that could lead to environmental problems when used extensively. Moreover, they are poor in nutrients, which limits their value as a fertiliser as well as their economic value. Also, the production volume in their current form far exceeds demand, which causes a management problem for the industries”, explains Miriam Pinto, a researcher from the Conservation of Natural Resources Department of NEIKER technology centre and member of the Basque Research and Technology Alliance (BRTA).

For this reason, there is a need to develop new strategies that can be used for recovering these types of materials. This is precisely the objective of the FERTILWASTES project that we are participating in, which aim is to optimise the value of this “waste” and its future in the market.

The European initiative has been challenged with developing innovative products and with value, such as biodegradable plant based materials, bio-stimulants or slow releasing fertilisers that are based on co-products generated using different agricultural waste treatment technologies. By developing these materials, the aim is to correct the nutritional deficiencies they currently have, improve the agronomic properties of the final products and achieve a differentiation compared to other products that are currently on the market.

Micro-algae for crops

Specifically and as part of the project, we will work with agricultural waste such as biochar (charcoal obtained from plant waste), digestates (waste generated after an anaerobic digestion process of plant material) and compost. These three co-products will be mixed and micro-algae will be added to this mixture. The result will be a fertiliser with a high nutritional value.

“Micro-algae are increasingly being used in modern agriculture applications. They provide more nutrients to crops and improve their performance, increase their fertility and the structure of the soils and even reduce the incidence of diseases”, according to researcher Sonia Suárez.

Moreover, the growing of these micro-algae will be carried out in other liquid waste from the agri-food industry. This waste will provide the nutrients required for growing micro-algae, in a manner that generates a circular bio-economy system to reduce the environmental impact of the liquid waste derived from these agri-food activities.

“The integration of different types of waste water in micro-algae production systems provides an authentic opportunity for developing circular bio-economy strategies. These microorganisms are capable of assimilating a wide range of organic and inorganic compounds present in liquid waste of different origins, converting them to valid biomass, which can be used as a raw material in many other applications and sectors”, adds the expert from NEIKER.

The FERTILWASTES initiative, financed with FEDER funds, is coordinated by APESA (Association Pour l’Environnement et la Sécurité en Aquitaine). Participating in this initiative are a consortium comprised of 6 R&D centres and universities from Basque Country, Catalonia and France: Beta-UVIC – CATAR Agroressources, UPC (Universidad Politécnica de Cataluña), NEIKER and LaTEP (Université de Pau et des Pays de l’Adour).