Development of reliable building bricks incorporating olive-mill wastewater focusing on thermal insulation and energy savings

Abstract

The present communication reports the development of reliable building bricks with improved thermal insulation behavior through substitution of the water mixed with the standard ceramic clayey raw materials with olive-mill wastewater (OMWW). This endeavor will contribute to circular economy and environmental protection as well as possible energy savings and CO2 emission reductions. OMWW is an aqueous by-product generated in large amounts during olive oil production processes. It is characterized by high COD values, low biodegradability, high toxicity, acidic pH, a high concentration of potassium and high solid matter content. Therefore, finding eco-friendly and economically viable solutions for OMWW treatment and valorization represents a significant challenge in the oilproducing countries, in order to avoid severe environmental problems from the uncontrolled disposal of this effluent. For that purpose, a series of ceramic brick specimens are fabricated with the introduction of either olive-mill wastewater or water employing a pilot-plant simulation of the industrial brick manufacturing procedures. The brick thermal conductivity and the mechanical performance are evaluated. According to the results obtained the replacement of fresh water by olive-mill wastewater in the ceramic manufacturing provides a production of lighter building bricks of a decreased thermal conductivity (hence increased thermal insulation capability) as well as an acceptable and a reliable mechanical strength. Furthermore, the energy consumption measurements reveal energy savings of as much as 30 % attained during the brick firing. © 2019, University of Chemical Technology and Metallurgy.