Bioremoval of Fluoride from Synthetic Water Using Gram-Negative Bacteria <i>Shewanella putrefaciens</i>

Abstract

In the present investigation, a defluoridation study was carried out using the bacteria Shewanella putrefaciens in the bulk phase as well as immobilized phase in a batch reactor. Growth of the bacterial cells and their acclimatization in a fluoride media as well as under substrate stress has been investigated. Optimization of process parameters for the removal of fluoride in the bulk phase is investigated and the performance under optimum conditions is compared with the simultaneous adsorption and bioaccumulation (SABA) process using Citrus limetta (mosambi peels) and Ficus religiosa (peepal) leaves as an adsorbent along with the bacteria. Optimum pH, nutrient broth (N.B.). media concentration, time and initial concentration were found 7, 2.5 g/L, 24&nbsp;h, and 20 mg/L, respectively. The simultaneous adsorption and bioaccumulation (SABA) process shows maximum fluoride removal capacity followed by bioaccumulation in bulk phase and adsorption. Both bioaccumulation and SABA are able to reduce the initial concentration of fluoride from 20 to below 1.5 mg/L.