Evaluation of a sulfidogenic system fed with microalgal biomass of Chlorella pyrenoidosa as an electron donor: Sulfate reduction kinetics

• Published in: International journal of hydrogen energy Vol. 47; no. 42; pp. 18566 - 18575
• Main Authors: Vasantharaj, K., Sivasubramanian, V., Velan, M., Vigneshwaran, C.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.05.2022
• Subjects: Chlorella pyrenoidosa; Desulfovibrio; Microalgal biomass; Sulfate reduction; Volumetric sulfate loading rate; Volumetric sulfate reduction rate; Sulfate reduction; Microalgal biomass; Chlorella pyrenoidosa; Volumetric sulfate loading rate; Desulfovibrio; Volumetric sulfate reduction rate
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2022.04.028

In this study, a sulfidogenic reactor fed with microalgal biomass of Chlorella pyrenoidosa as an electron donor was operated in a continuous mode. This study evaluated the influence of various initial sulfate concentration from 1.0 to 2.5 g/L on anaerobic sulfate reduction kinetics by a sulfidogenic enrichment culture predominantly Desulfovibrio sp. VSV2. It was observed that volumetric sulfate reduction rate (VSRR) was consistently increasing with an increase in volumetric sulfate loading rate (VSLR) across the retention time of 7–10 days. For a retention time of 7 days, the maximum VSRR was noted as 0.0050 g/(L.h) with a corresponding VSLR of 0.0089 g/(L.h). When retention time was maintained for 10 days, a maximum sulfate reduction of 65% and a maximum bacterial concentration of 1.632 g/L were achieved for an initial sulfate concentration of 1.5 g/L. It was concluded that VSLR facilitated through both dilution rate and initial sulfate concentration had a significant influence over sulfate reduction kinetics. The results of the study suggested that the microalgal-fed sulfidogenic system could be effectively employed for reduction of sulfate from sulfate-rich wastewater. [Display omitted] •Sulfidogenic enrichment culture predominantly Desulfovibrio sp. VSV2 shows effective sulfate reduction.•Present study evidenced high feasibility of using Chlorella pyrenoidosa biomass as electron donor.•Initial feed sulfate concentration and VSLR had a strong influence over sulfate reduction kinetics.•A maximum sulfate removal efficiency of 65% could be achieved using the present sulfidogenic system.