Studies examining the effects of using olive waste in the manufacturing of clay bricks have revealed that they can be effective building materials.
Waste from the olive oil industry like olive stone ash, ground olive stones, and sludge from pomace oil extraction can be used as effective secondary raw materials in the making of clay bricks and cement paste.
The extraction of pomace oil and the process of oil refining create waste water in the form of sludge. This is sometimes used as a fertilizer in agriculture but most often it’s dumped in landfills or water bodies, or incinerated — creating a negative environmental impact.
A 2015 study titled Reusing of Oil Industry Waste as Secondary Material in Clay Bricks by the Department of Chemical, Environmental, and Materials Engineering at the University of Jaén, Spain, found that the use of sludge leftover from pomace oil extraction in the making of clay bricks had a similar compressive strength as conventional bricks, but they had better thermal conductivity.
The study also revealed that industrial oil waste products like sludge, as well as spent filtration and bleaching earth (both are used for refining oils) can be used effectively as substitutes to brick clay because their chemical composition closely resembles it.
The same research team released an article in 2016 that evaluated the use of olive stone ash as a secondary raw material for fired clay bricks. It found that adding 10 to 30 wt% (weight percent) of olive stone ash to clay had a “pronounced effect on the evolution of physical and mechanical properties of the resultant bricks fired at 900°C.” However, adding higher proportions “decreased the compressive strength and bulk density of bricks” while increasing their porosity and rate of water absorption.
Another 2016 study looked at the effects of the addition of ground olive stones on the physical and mechanical properties of clay bricks.
It analyzed the properties of bricks made with clay and ground olive stones and found that the addition of the latter reduced water absorption which can have a positive effect because it decreases the chance of crumbling while creating a good bonding effect.
The study also revealed that the addition of ground olive stones improves the thermal conductivity of the bricks but decrease their mechanical properties compared to pure clay bricks. Tests also showed that that overall compressive strength values surpassed the minimum requirements set by existing regulations.
The study concluded that clay bricks manufactured with ground olive stones “offer excellent returns on the energy used in firing”, and “are recommended as one of the most cost-effective alternative additions that can be used in fired clay brick manufacturing.”
The reuse of these olive waste products as alternative raw materials in the construction industry not only reduces industrial waste but can also offset the cost of raw materials. At the same time, this is an eco-friendly and sustainable way of recycling waste that also saves natural resources.
More articles on: sustainability
Dec. 14, 2023
Tightening Water Regulations in California May Spur Olive Cultivation
While irrigated olive groves still use plenty of water, increasingly strict prohibitions, especially in the San Joaquin Valley, may carve out a new niche for dryland olive groves.
Aug. 14, 2023
Italy Set to Invest €100M for Olive Mill Upgrades
Starting in 2026, funds will be dispersed to millers across the country to upgrade equipment and technologies.
Nov. 1, 2023
Olive Trees Can Help Beat Climate Change
At a three-day conference, the International Olive Council emphasized the role olive farming can play in efforts to reach global net zero emissions.
Sep. 13, 2023
California Olive Farmers Embrace Regenerative Agriculture to Combat Climate Challenges
After the initial investment, California farmers say regenerative farming practices enhance soil health, fight pests and improve oil quality.
Sep. 26, 2023
How Monovarietal Olive Oils Promote Ecological Farming, Safeguard Landscapes
Producing monovarietal extra virgin olive oil promotes endemic varieties, which require fewer phytosanitary interventions, preserve landscapes and promote biodiversity.
Sep. 6, 2023
The Art of Permaculture in Central Italy
The advice of a friendly neighbor inspired the founders of the Italian company Carma to choose a sustainable path to success.
Dec. 11, 2023
Organic Farm in Jaén Blazes a Trail for Selling Carbon Credits
O.Live generates about 4.5 carbon credits per hectare from its 1,000 hectares of organic groves, establishing a model for producers to increase revenue.
Aug. 10, 2023
Asphalt Made with Olive Oil Byproducts Used to Pave a Highway in Spain
Local officials said the experimental asphalt is more environmentally friendly to manufacture, safer for workers and could provide new revenue for producers.