Assessment of olive mill solid residue (pomace) as an additive in lightweight brick production

The disposal of olive oil industrial waste is an environmental problem regardless of the manufacturing process. Contamination of soils with wet pomace (a waste product of the two-phase olive oil extraction method) can be a serious problem. Moreover, it cannot be composted or burned without expensive pre-treatment. In this work, we used wet pomace as a pore-forming additive in the manufacture of clay bricks to evaluate the possibility of obtaining a lightweight construction material with good insulating characteristics. To this end, bricks were prepared by adding 5, 10, 15, 20, and 25 wt% wet pomace to the clay without additional water. The results indicate that the incorporation of 10 wt% wet pomace is beneficial for manufacturing good-quality bricks, obtaining an apparent density of 1.43 g/cm3, a compressive strength of 40.22 MPa, and a thermal conductivity of 0.72 W/mK.

► Wet pomace as an additive in brick manufacture would mean the disposal of a highly polluting waste product.
► It would reduce manufacturing costs by eliminating the need for added water in the brick mixture.
► The wet pomace in the brick mixture increases material porosity and thereby its application as insulation.