Olive pomace as fertiliser: Treurer’s circular economy model

Can a 17th-century Mallorcan olive grove be a model for the future? At Finca Treurer, the answer is yes. While the sustainability debate fills headlines, this family estate in Algaida has spent years building a real, concrete and measurable circular economy system: one in which every by-product of olive oil returns to the land that generated it, and nothing is lost along the way.

Contenidos / Contents

• An olive grove with history and a vision for the future
• Olive pomace as fertiliser: from hazardous waste to ecological resource
• How compost is made at Treurer: the technical process
• More circular economy practices in the olive grove
  • Solar energy and reused water: the numbers that matter
• Certification and agronomic rigour
• Agritourism as part of the circular economy
• Mallorcan tradition and circular economy: two sides of the same coin
• Frequently asked questions

An olive grove with history and a vision for the future

The estate sits on es Pla, the central plain of Mallorca, facing the Puig de Randa. Joan Miralles planted three thousand arbequina olive trees here nearly two decades ago with a clear idea: to produce an extra virgin olive oil that reflected the character of the island — natural, sustainable and honest. Today, his son Miquel leads the project with the same conviction, but with more sophisticated tools.

What began as a family venture has become a benchmark in the sector. Treurer has received international recognition — gold medals at the NYIOOC in New York and first place in the Guía Iber Oleum — and, at the same time, has built a model of sustainable practices that goes far beyond green marketing. Circular economy is not a slogan here: it is the architecture of the business.

As Miquel Miralles explains, “the land, the sun and the trees produce the oil; our only task is to extract it with respect, dedication and high standards”. That philosophy permeates every agronomic and environmental decision on the estate.

Olive pomace as fertiliser: from hazardous waste to ecological resource

The great environmental challenge for any olive mill is the olive pomace: the solid paste left after pressing the olives to extract the oil. It contains remnants of pulp, skin and olive stone, and for decades it was classified as a problematic waste with contaminating potential for soils and aquifers. The standard practice in the sector is to hand it over to pomace extraction plants or manage it as industrial waste, with the economic and environmental costs that entails.

At Treurer, olive pomace has become the heart of its circular economy project. The estate mixes the pomace with shredded leaves and branches from the olive grove to produce high-quality organic compost, which is then returned to the soil as a natural fertiliser for the trees themselves. The circle closes elegantly: what the olive generates when transformed into oil returns to nourish the roots of the very tree that produced it.

This project was recognised by the Consell de Mallorca, which selected it as a beneficiary of the first circular economy subsidy scheme from the Department of Sustainability and the Environment. The grant — 20,000 euros — provided the necessary impetus to move from idea to reality. The objective was clear: to improve the environmental impact, reduce the ecological footprint and minimise the generation of olive-related waste on the island.

The project was implemented in September 2022, in parallel with the installation of the estate’s new olive mill. This was no coincidence: renewing the production facilities and redesigning waste management at the same time is the most coherent way to build a circular system from the ground up.

How compost is made at Treurer: the technical process

Understanding why Treurer’s model works requires a closer look at the actual process. Composting olive pomace does not mean piling up waste and waiting: it requires active management of the mixture, aeration and moisture so that the organic matter decomposes in a controlled way without generating odours or contaminating leachates.

At Treurer, the process follows these main phases:

1. Initial mixing: fresh olive pomace — with a moisture content of between 25% and 35% — is combined with shredded pruning remains (branches and leaves) in a ratio that balances the carbon from the wood with the nitrogen from the olive paste. This mixture is key: pomace alone tends to compact and ferment anaerobically, generating phytotoxic compounds.
2. Thermophilic phase: during the first few weeks, microbial activity raises the temperature of the pile above 55 °C, eliminating pathogens and weed seeds. During this phase, periodic turning is carried out to ensure uniform oxygenation.
3. Maturation: after the active phase, the compost rests for three to six months. During this period, the phenolic compounds in the pomace — responsible for its initial toxicity — progressively degrade to levels that are harmless to the soil.
4. Application to the olive grove: the mature compost is incorporated into the soil around the olive trees, providing organic matter, improving soil structure and reducing the need for synthetic fertilisers.

The result is a fertiliser rich in potassium, phosphorus and micronutrients, perfectly adapted to the nutritional needs of the Mediterranean olive grove. And, unlike conventional fertilisers, it leaves no synthetic residues in the soil or in the final oil.

More circular economy practices in the olive grove

The circular economy at Treurer does not end with olive pomace. The estate has developed a set of measures that affect every corner of the production process. Here is an overview:

• Pruning remains as ground cover: instead of burning them — the common practice in most olive groves — the branches are shredded and used to cover the pedestrian areas of the estate, avoiding herbicides and protecting the soil from erosion.
• Treated water from the agritourism: the olive grove’s irrigation system is fed by the treated water generated by the agritourism guests themselves, closing a cycle that directly connects human consumption with oil production.
• Photovoltaic solar energy: the solar panels installed on the estate reduce dependence on the electricity grid, with an investment backed by an energy efficiency grant for tourist establishments.
• Olive pomace composting: the main by-product of the mill is transformed into organic fertiliser that returns to the olive grove, eliminating the waste at source.
• Local suppliers and employment: the estate works with suppliers from the municipality of Algaida and employs people from the area, extending the circular principle to the local economy.

Solar energy and reused water: the numbers that matter

Putting figures to sustainability is what makes it credible. At Treurer, the photovoltaic installation covers a significant share of the energy consumption of the mill and the agritourism during the months of greatest solar irradiation in Mallorca, reducing both the electricity bill and associated emissions. The treated water reused for irrigation avoids additional extraction from aquifers on an island where water pressure is a growing structural problem. Every litre that returns to the olive grove is a litre that is not extracted from the subsoil.

This decision connects directly with the principles of regenerative agriculture: not only producing without causing harm, but returning more to the ecosystem than is taken from it. The soil is kept alive, the biodiversity of the olive grove is preserved and the landscape gains in coherence.

Certification and agronomic rigour

Good intentions without external verification are not enough. That is why the agricultural management of Finca Treurer is carried out according to integrated production criteria, a standard certified by the Conselleria d’Agricultura de les Illes Balears that guarantees the cultivation of the olive grove is carried out with the minimum possible environmental impact, combining traditional techniques with up-to-date agronomic knowledge.

Behind this certification lies constant work: pest control without unnecessary pesticides, soil management without aggressive tillage and rigorous technical monitoring of the condition of the trees. Miquel Miralles, with a background in economics and law and more than fifteen years of experience in the olive oil sector, leads this process alongside a team of agronomists who accompany every campaign.

The regenerative agriculture practised by Treurer is not just a label: it means returning organic matter to the soil, maintaining ground cover and respecting the natural cycles of the olive grove. In a context of climate change and growing water pressure in the Balearic Islands, these practices are not a luxury but a strategic necessity for the long-term survival of the crop.

Agritourism as part of the circular economy

There is a dimension of the circular economy at Treurer that often goes unnoticed: agritourism. When a visitor chooses to stay at the estate instead of a beach hotel, they directly contribute to financing the maintenance of the olive grove, the machinery, the facilities and the human team that makes an oil of this quality possible.

This is not an abstract contribution. Pruning, irrigation, manual harvesting: everything has a real cost. The agritourism — recently upgraded to five stars — generates the income that allows a productive model to be sustained that would otherwise be economically unviable without compromising quality or environmental standards.

Furthermore, the estate works with local suppliers and employs people from the municipality, generating a circular economy that distributes wealth among the community of Algaida and the interior of the island. In contrast to coastal tourism, which concentrates economic impact at a few points, this model distributes the flow of visitors and economic benefit more evenly.

Treurer extra virgin olive oil appears at every breakfast, every tasting, every dish in the estate’s restaurant. That coherence between what is produced and what is served is one of the hallmarks of quality gastronomic tourism in Mallorca: the visitor does not consume a product brought from elsewhere, but the fruit of the very soil they are standing on.

Mallorcan tradition and circular economy: two sides of the same coin

There is something deeply Mallorcan about the idea of wasting nothing. For centuries, families in the interior of the island managed their resources with a circular logic out of necessity: water was collected, organic remains were composted, animals fertilised the fields. Modernity broke that cycle. Treurer is rebuilding it with 21st-century tools.

The Serra de Tramuntana, inscribed as a UNESCO World Heritage Cultural Landscape in 2011, is the most visible example of how Mallorca’s traditional agricultural systems can be, at the same time, cultural heritage and a model of sustainability. Treurer’s olive groves, in the heart of es Pla, belong to that same tradition.

The circular economy is not an imported trend. In Mallorca, it has roots. And at Finca Treurer, those roots reach down to the olive trees: literally, the compost made from olive pomace and pruning remains feeds the very trees that have been bearing fruit for decades. That is living heritage. That is sustainability with soul.

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