Biological Removal of Fluoride from Industrial Waste Water

Abstract

newline newlineIn the present study, the two most suitable natural bioadsorbents Citrus limetta peels and Ficus religiosa leaves are screened on the basis of high removal capacity of fluoride and these bioadsorbents have been used for the fluoride removal from synthetic waste water. Effects of process parameters like solution pH, contact time, adsorbent dose, particle size, temperature and initial fluoride concentrations from synthetic waste water have been investigated. Peepal leaves has been found to be most efficient in terms of its capacity to remove fluoride 74 percent than mosambi peels 67.5 percent at 20 mg per litre initial concentration of fluoride under optimum conditions. To facilitate mathematical modeling adsorption kinetics models as well as adsorption isotherms have been developed. From the results of batch study mosambi peels are selected for column study. All the experiments were conducted under optimum conditions in column reactor which is packed with mosambi peels of 1.18 millimeter particle size. It is concluded that the column performs better with lower feed flow rate and higher bed height. Biological treatments with bacterial whole cells is another important route for fluoride removal from water in which whole cells are used either in bulk phase or are immobilized on a solid support. Immobilized whole cells produce bio-layer on bioadsorbent surface and when treated with solution having fluoride, the bacterial cells bioaccumulate it within the cell as well as it gets adsorbed on bioadsorbent surface. This process is termed as simultaneous adsorption and bioaccumulation process. In the present work whole bacterial cells of Shewanella putrefaciens MTCC 8104 has been selected from literature and screened as fluoride resistant bacteria on the basis of their fluoride removal capacity in bulk phase as well as in continuous mode. Effect of empty bed contact time and bed height of bio-column reactor bed on the removal of fluoride has been investigated. Further, the efficiency of SABA process has also