Biogenic sulfides for sequestration of Cr (VI), COD and sulfate from synthetic wastewater

Abstract

The aim of this work is to explore the possibility of using mixed culture of mesophilic sulfate-reducing bacteria (SRB) for retrieval of toxic and carcinogenic Cr (VI) from synthetic solution. In order to treat Cr (VI) containing wastewater effectively, SRB culture was adapted to 50 mg/L Cr (VI) and maintained through repeated sub-culturing to enhance the growth and activity of SRB. Batch biosorption experiments were carried out in glass serum vials by cultured SRB, accomplishing the removal of 82.1% Cr (VI), 76.9% sulfate, 85.7% COD under the following optimized conditions: pH 7, hydraulic retention time (HRT) 7 days, temperature 37 • C and initial Cr (VI) concentration of 50 mg/L. Further sorption experiments were conducted on synthetic wastewater under optimal operational conditions and resulted in 89.2% Cr (VI), 81.9% COD and 95.3% sulfate reduction from simulated wastewater. The results of this work contributed to a better understanding of metal uptake by biogenic sulfides and would be beneficial in the development of potential biosorbents that possess high capacities for Cr (VI) uptake from aqueous environments.

Metals-induced functional stress in sulphate-reducing thermophiles

“…Chromium appeared relatively less toxic to the SRB than copper as bioprecipitation and sulphate uptake were even noted at higher concentrations (15 ppm) in this case. This finding was consistent with the previous literature values for toxic concentrations, which were lower for copper than chromium (Cabrera et al 2006 ; Ahmadi et al 2015 ; Verma et al 2015 ). The reason for this difference in cell deactivation could be due to interactions with the bacterial cultures, although further investigations into the exact mechanisms are required to obtain a deeper understanding of this phenomenon as reported earlier by Cabrera et al ( 2006 ).…”

Potential of Autochthonous Sulfate-Reducing Microbial Communities for Treating Acid Mine Drainage in a Bench-Scale Sulfidogenic Reactor

“…For inoculation pH ~ 5, however, the observed sulfate removal (~21 mmol) was significant based on the AMD sulfate concentration (~16 mmol). Sulfate removal values at pH 5 (41%) and pH 7 (44%), similar to that in this study, were demonstrated by Verma et al (2015). At pH 5, Jong and Parry (2006) also obtained sulfate reduction values similar to that in this experiment (43%).…”

Bio-Electroreduction of Chromium (VI) using Immobilized Sulfate Reducing Bacteria on Conductive Microbial Cellulose Biocathode

“…Marques et al investigated the removal of chromium and lead (80 and 200 ppm) with SRB and reached an e ciency of 90% in chromium removal and 65% in lead removal after 180 hours. Verma et al investigated the removal of 50 mg/ L Cr (VI), sulfate, and COD in SRB environment with a retention time of 7 days, pH of 7, at 37°C and achieved 76%, 77% and 87% removal of chromium, sulfate, and COD, respectively [22]. The obtained results shows that the biological adaptation time was lower than the other simmilar biological process.…”