Don’t throw that leftover: Researchers are turning food waste into farming gold

When Miriam Pinto goes to her usual supermarket, in Basque Country, Spain, she faces a problem common to a lot of people: many of the fresh foods are only available in family-size packs.. 

“In supermarkets, no thought is given to the couples or the single people,” said Pinto, senior researcher at the Neiker-Tecnalia Basque Institute for Agricultural Research and Development. If a single person wants two apples, they are then forced to buy six due to the way they are bundled.

“In the end you have many more apples than what you need and have to throw them away.”

Food waste is a major issue in the EU, with each inhabitant wasting 132 kg of food every year. More than half of the food wasted, 54%, is generated by households, while other losses occur in catering and hospitality, as well as on farms and in supermarkets. Globally, around one fifth of all food produced is wasted at retail, food service and household level.

The consequences of this are manyfold. Despite wasting so much food, almost 33 million people in the EU – roughly 7.3% of the population – can’t afford a meal every second day. Producing food emits carbon, and the use of pesticides and other agrochemicals can have a negative impact on biodiversity. By throwing food away, we are unnecessarily damaging the environment. 

In the middle of February, the EU agreed on targets for food waste reduction in the bloc, which have yet to be formally adopted. These targets aim for a 10% reduction in production and manufacturing waste, and a 30% reduction in waste from retail, restaurants, food services and households.

Although Pinto believes that reducing food waste is possible, she also acknowledges that it is a difficult process to put in place as it involves changing consumers and customers habits. Restaurants, for example, have to prepare food in advance in the event of a busy day.

“It is hard for them to predict if they are going to sell all the food that they have or not”

Pinto is the coordinator of the EU-funded LANDFEED project, which looks to use food waste to create biofertilisers for agriculture. Although food might still be wasted, Pinto argues that we should at least capture the nutrients contained inside.

“It is not the ideal solution, but it is a way to recuperate, recycle, and reuse something”

A number of case studies are being tested within this project. Alongside catering waste, researchers will also be looking at utilising waste from olive oil manufacturing process and sludge from wastewater treatment, among other technologies. 

As the project is still in its early phases, the work is currently mostly focused on making decisions on raw materials sourcing. One issue with catering waste, for example, is that people change what they eat along the seasons, and different feedstocks can impact the process.

“We have to develop techniques that work for both potatoes and salads,” Pinto says.

Most of the technologies used in the research project are not, however, starting from scratch. By the end of it, Pinto hopes that the technologies will be completely proven and ready for market. 

For catering waste, the plan involves the use of fungi in a fermentation process to break down the food into a biofertiliser.

Giuseppe Mancini, professor in chemical engineering at the University of Catania, Italy, is investigating how the waste from oranges production can be used in combination with other non-food feedstocks, like sludge left over from wastewater treatment. “These are two important agroindustrial processes in Sicily and Italy, which generate these kinds of residues,” he says.

Other inputs like volcanic ashes are being studied too. As opposed to fungi fermentation, Mancini and his team are looking into a composting process, which involves one step of drying out the wastewater sludge.

“We are trying to use a sustainable approach for drying, just like solar greenhouses that use energy from the sun to remove the humidity from the sludge”

As next steps in the project, the team will  do pot experiments, varying combinations of chosen feedstocks, to see which ones produce the best biofertilisers.

Biofertilisers are a little different to standard fertilisers. “The contribution in nutrients is not the same as a chemical fertiliser, which is much more powerful in releasing nitrogen and phosphorus,” he says. The biofertilisers will have other nutrients that will help restore humidity to the soil and make it more fertile, an important contribution in areas like Siciliy with arid soils. 

Another benefit of the biofertilisers is the traceability – as it is clear where all the residues are coming from, as well as how they are being transported and managed.

On top of biofertilisers, Pinto's project is creating the basis for markets to convert waste into useful agricultural products. Mancini mentioned a collaborative platform – called Industrial Symbiosis – a platform being developed to enable producers to offer residues that others can use, thus creating a network of companies based on mutually beneficial opportunities. 

“As there are a lot of things that are thrown away, the same goes for all the nutrients,” Pinto says. For her,  LANDFEED and making biofertilisers comes down to one thing: “Maybe you are wasting food, but at least you are saving nutrients.”

illuminem Voices is a democratic space presenting the thoughts and opinions of leading Sustainability & Energy writers, their opinions do not necessarily represent those of illuminem.