Development of a sulfidogenic bioreactor system for removal of co-existent selenium, iron and nitrate from drinking water sources. (15th January 2020)

• Record Type: Journal Article
• Authors: Sonkeshariya, Himanshu; Shakya, Arvind Kumar; Ghosh, Pranab Kumar
• Is Part Of: Journal of environmental management. Volume 254(2020)
• Publication Date: 2020-01-15
• Subjects: Selenium -- Iron -- Nitrate -- Selenium sulfide -- Achavalite -- Drinking water; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2019.109757
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: The present study showed for the first time that selenium, iron, and nitrate could be simultaneously removed in a sulfidogenic bioreactor to meet drinking water standards. A bioreactor inoculated with mixed bacterial consortium was operated for around 330 days in anoxic environment at 30 °C under varying combination of influent selenate (200–1000 μg/L as selenium), and iron (3–10 mg/L) in presence of 50 mg/L of nitrate. Required amount of acetic acid (as carbon source) and sulfate were supplied and the reactor was operated at different empty bed contact time (EBCT) of 45–120 min. Along with complete removal of nitrate, the reactor removed both selenium and iron to meet the drinking water standards. Field emission transmission electron microscopy (FETEM) and X-ray diffraction (XRD) analyses confirmed the formation of selenium sulfide (SeS), achavalite (FeSe) and pyrite (Fe S 2 ), which were the possible removal mechanisms of selenium and iron. Thus, this study exhibited that selenium, iron, and nitrate can be simultaneously removed to meet the drinking water standards in a sulfidogenic bioreactor. Graphical abstract: Image 1 Highlights: First report on biological removal of co-existent selenium, iron and nitrate. First report on bio-removal of Se and Fe to meet BIS drinking water standards. Concentration assayed: Se = 200–1000 μg/L, Fe = 3–10 mg/L and NO3 − = 50 mg/L. SO4 2− and EBCT plays a major role in Fe and Se removal. Bio-precipitation of SeS, FeSe and Fe S 2 were the removal mechanisms of Se and Fe.