Innovative Precipitation-Flocculation Process for Treating Turbid Waters from Gualaxo do Norte River, Brazil
- 5 Downloads
Physical and chemical characterization and solid/liquid separation of turbid waters from a river affected by an iron tailing rupture disaster (Gualaxo do Norte River, Brazil) were studied at bench scale. Parameters such as turbidity, pH, surface tension, electrical conductivity, total suspended solids (TSS), particle size distribution (micro- and nanoparticles), and zeta potential were analyzed from samples collected at three different river depths. The results in all samples showed the presence of micro- and nanoparticles, ranging in diameters from 100 nm to 200 μm. Best results for flocculation and settling were obtained at pH 7.5, through an innovative combination of eco-friendly reagents: (i) ferric hydroxide precipitates (10 mg L−1 Fe3+) to sweep (enmesh) the dispersed solids and (ii) gelatinized starch (5 mg L−1) to form large flocs. The results showed removals between 90 and 100% of total suspended solids (micro- and nanoparticles), resulting in clear water with residual turbidity < 7 NTU. It is believed that this innovative alternative has a high potential for flocculating and treating the turbid water at Gualaxo do Norte River, assisting the water treatment stations.
KeywordsPolluted rivers Turbid water Flocculation Corn starch
The authors thank the Brazilian Institutes, namely, CNPq, CAPES, and Renova Foundation, for supporting our research. Special thanks to our University—UFRGS—and to all students for their collaboration.
Compliance with Ethical Standards
Conflict of Interest
The authors declare that there is no conflict of interest.
- 1.National Department of Mineral Production – DNPM (in Portuguese), 2016. Sumário Mineral. Vol. 35. Available at: http://www.dnpm.gov.br/dnpm/sumarios/sumario-mineral-2015. Accessed on April 2019
- 4.Fuerstenau MC, Yoon RH, Jameson GJ, 2007; Froth flotation: a century of innovation. Society for Mining, Metallurgy, and Exploration-SME, ISBN: 978-0873352529, 891Google Scholar
- 7.Water National Agency - ANA (in Portuguese), 2017. Encarte especial sobre a qualidade das águas do Rio Doce após 2 anos do rompimento da barragem de Fundão 2015–2017. Available at http://www3.ana.gov.br/portal/ANA/sala-de-situacao/rio-doce/documentos-relacionados/encarte-qualidade-da-gua-do-rio-doce-dois-anos-apos-rompimento-de-barragem-de-fundao-1.pdf. Accessed on August 2018
- 8.Golder Associates, Brasil Consultoria e Projetos Ltda. Programa de Caracterização Geoquímica de Rejeitos, Solos e Sedimentos, 2007. Available at https://www.fundacaorenova.org/arquivos-e-relatorios/. In Portuguese. Accessed on August, 2018
- 9.Water National Agency – ANA (in Portuguese), 2016. Conjuntura dos Recursos Hídricos no Brasil Informe 2015. Available at: http://www3.snirh.gov.br/portal/snirh/centrais-de-conteudos/conjuntura-dos-recursos-hidricos/encarteriodoce_22_03_2016v2.pdf. Accessed on August, 2018
- 10.European Chemicals Bureau, 2002. European Union Risk Assessment Report: acrylamide. Vol. 24. CAS No: 79-06-1. EINECS No: 201-173-7. Available at: https://echa.europa.eu/documents/10162/50218bf9-ba0f-4254-a0d9-d577a5504ca7. Accessed on August 2018
- 15.Rao KH, Forssberg KSE. (2007) Chemistry of iron oxide flotation. In: Fuerstenau MC, Jameson GJ, Yoon R-H, editors. Froth flotation: a century of innovation. Littleton, Colorado: Society for Mining, Metallurgy, and Exploration - SME. p. 498–513Google Scholar
- 19.Hendricks DW 2006. Water treatment unit processes: physical and chemical. 1st Ed., CRC Press, ISBN 9780824706951, Chapter 3, page 310Google Scholar