Microbial Enhancement of Selenium Removal in Chemically Modified Zeolite Columns

Selenium (Se) is an essential micro-nutrient for living organisms, but elevated concentrations in water can adversely affect health. In this research, we investigate the removal of selenium oxyanions (selenate and selenite) aqueous systems by integration adsorption on modified zeolites microbial reduction. Dynamic sorption-reduction experiments were conducted using two sets zeolite columns selenite selenate oxyanions, respectively. each case, one column was fully packed with natural, unmodified zeolites, while other composed 80% natural 20% iron-coated mass. The initial concentration, (SeIV) or (SeVI), 790 μg/L, pH 7.5, flow rate 3 mL/min. Initially, as expected, higher (34%) observed coated zeolite, twice high compared to results zeolite. Maximum 89% Within approximately 14 days, biofilm developed inside columns, reduction all four reached 99%. Biofilm community composition, assessed 16S rRNA sequencing, consistent presence mainly selenium-reducing bacteria (Veillonella, Bacteroides, Escherichia). reduced elemental selenium, visible within bioreactors red-color aggregates.