Environmental benefits of using sewage sludge in the production of ceramic bricks

Abstract

The production of sludge from the sewage treatment plants is increasing as a result of population increase and public policies to improve the sanitation sector. This sludge presents a potential risk to health and the environment representing major challenge for sanitation companies regarding treatment and final disposal of this material. The solution is in the circular-economy concept: this sludge presents favorable characteristics to be used as rawmaterial in the ceramic industry. This study seeks to quantify the environmental impacts related to the atmospheric emissions caused and to the consumption of resources when 10% of clay is replaced by sewage sludge in the production of bricks. Life cycle assessment tools were used to establish a comparison between the common scenario of the brick production using ceramic mass only from clay and the scenario with the incorporation of 10% of sewage sludge. The results revealed that the incorporation of the sewage sludge has multiple benefits, regarding the decrease of the environmental impacts in all the categories studied: 15% in the energy savings, 15% in the terrestrial acidification and the formation of fine particles, 10% in scarcity of mineral resources and 8-10% in formation of photochemical ozone.