The oil extraction process generates some 70,000 tons of alperujo, organic waste that is currently used directly as fertilizer and, to a lesser extent, as fuel.

The Technological Development Unit (UDT) of the Universidad de Concepción with the collaboration of ChileOliva, AChBiom and the companies Terramater and Acacios, are making progress in creating activated carbons and solid biofuel from olive oil industry waste. The innovation, supported by the Foundation for Agricultural Innovation (FIA), seeks to modernize the industry towards intelligent production processes, in the path of the Circular Bioeconomy.

In Chile there are about 22,200 hectares of olive trees that produce approximately 22,500 tons of oil per year for the domestic and international market. The oil extraction process generates about 70,000 tons of alperujo (pressed in 2 phases) and orujo (in 3 phases), which are organic residues with a high water content, and which are currently used directly as fertilizer and, to a lesser extent, part of the olive pit is recovered for use as solid fuel.

Thus, the Universidad de Concepción, through the Technological Development Unit, UDT, is executing the project supported by the Foundation for Agrarian Innovation (FIA): “Innovative solution for the valorization of waste from the olive oil industry: Development of activated carbons and biofuel”, which proposes the integral valorization of waste through the development of activated carbons, taking advantage of the intrinsic characteristics of the olive pit, and the production of densified solid biofuels using the olive pomace and/or pomace.

The initiative, which began in September 2019 and is in its final stage of execution, succeeded in developing and validating an alternative for the integral use of olive oil production residues, which consists of producing adsorbent materials and fuel pellets. The process begins with the separation of the olive pit from the olive pomace, followed by dehydration of the organic residues with high moisture content and the formulation of fuel pellets for industrial use from mixtures of olive pomace and wood sawdust. Olive pits are used as raw material in the synthesis of activated carbons, following a procedure that allows customizing the properties of these materials, thus broadening the range of their potential uses as adsorbent materials.


Eucalyptus sawdust pellets were characterized according to tests established in the Chilean Standard for Solid Biofuels NCh-ISO 17225-2 and tested in a 150 kW heating boiler. The fuel properties were similar to commercial wood pellets and with NOx levels below the requirements of the future emission standard for small and medium boilers.

With respect to the synthesis of activated carbons, which are used as adsorbent materials in odor removal systems of industrial gas streams, in water cleaning filters or in the recovery of metals among other applications; studies were carried out at the laboratory level of olive pit activation using physical methods (with high temperature steam and CO2) and chemical methods (with phosphoric acid H3PO4 and potassium hydroxide KOH). Depending on the activation process and experimental conditions, activated carbons with high surface area, different levels of micro and meso porosity and differentiated surface chemical properties were achieved. A pilot activation infrastructure was implemented and activated carbons were produced at a demonstration level using physical activation with steam (most commonly used process) and chemical activation with phosphoric acid. The steam activated carbons were granular, with good mechanical resistance, high surface area (1200-1400 m2/g) and with a micro and meso porous structure (70% micropores), which makes them highly effective for removal of mercaptans (compounds responsible for bad odors) and for removal of organic pollutants in liquid streams.

In addition to the experimental results, technical and economic pre-feasibility studies were carried out and work was done on the development of business models that could be applied to the productive reality of the agroindustrial sector. In addition, progress was made in identifying key actors for the commercial development of both products.

Both proposals, to develop activated carbons and densified solid fuels from olive oil industry waste, are innovative technological alternatives that can contribute to the sustainability, innovation and competitiveness of SMEs in the sector. Similarly, this innovation can be implemented for the utilization of waste from the fruit sector, such as fruit hulls and nut shells.

Source: El Mercurio, Tuesday, December 28, 2021, body D, page 5.