Application of residual biochars in constructed wetlands focusing on innovation and sustainability in wastewater treatment

• Ano de defesa: 2025
• Autor(a) principal: Carmona, Iara Nobre
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Adsorção; Adsorption; Decentralized sanitation; Lignocellulosic waste; Pollutant removal; Remoção de poluentes; Resíduos lignocelulósicos; Saneamento descentralizado
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/11/11150/tde-04062025-145156/

Pollution of water resources by organic and inorganic contaminants represents a significant environmental challenge, driving the search for efficient and sustainable technologies for effluent treatment. Among the emerging alternatives, the use of biochar in constructed wetlands stands out due to its high adsorption capacity and structural stability. In this context, this thesis aimed to investigate the use of residual biochars as a filter medium in vertical flow constructed wetlands for the treatment of sanitary sewage. Chapter 1 presents a bibliometric analysis of advances and research trends in the use of biochar in constructed wetlands for wastewater treatment. The results demonstrate the growing scientific interest in the area, with emphasis on the removal of organic and inorganic pollutants. However, the need for large-scale studies and greater representation of research in tropical countries was identified. In Chapter 2, the physicochemical properties and adsorptive efficiency of biochars produced from residual wood of Eucalyptus sp. were evaluated. and Citrus sinensis in the removal of methylene blue. Eucalyptus sp. biochar pyrolyzed at low temperature (250-350 °C) showed greater efficiency in dye removal, attributed to its chemical composition, ash content, and functional groups that favored electrostatic interactions and ion exchange mechanisms. Chapter 3 explored the construction and evaluation of vertical flow constructed wetlands using lignocellulosic waste biochars as a filter medium in the treatment of sanitary sewage. The prototype containing Citrus sinensis biochar pyrolyzed at 500 °C showed better performance in the removal of organic matter (91%), nitrate nitrogen (90.4%), and settleable solids (100%), in addition to reducing Escherichia coli by up to 88%, meeting the standards for agricultural reuse. Scanning electron microscopy (SEM) revealed that its porous structure favored both pollutant adsorption and microbial colonization. The results of this thesis demonstrate that the use of residual biochars can improve the efficiency of constructed wetlands, becoming a viable alternative for decentralized effluent treatment. In addition to contributing to the reduction of water pollution, this approach promotes the valorization of lignocellulosic residues, aligning with sustainable practices. As future perspectives, it is suggested to carry out long-term studies to evaluate the stability of biochars in the filter media, as well as investigations on their application on a real scale and integration with complementary technologies.