Abstract:
Traditional microbial desalination cells (MDCs) face challenges related to expense and
reduced efficiency due to the necessity of expensive catalysts or aeration for reduction
reactions at the cathode. A possible way to overcome these challenges is by employing
microalgae as a biocatalyst in MDC’s cathode chamber. This research aims at
comparing the performance efficiency of photosynthetic MDC (PMDC) inoculated
with a biocatalyst, Scenedesmus obliquus, in the cathode chamber against the
conventional aerated MDC. The performance of these systems was examined by using
various substrate concentrations of 2000, 4000 and 6000 mg/L at the anode and
different salt concentrations of 15, 25 and 35 g/L at the desalination chamber. The
results demonstrated that PMDC performed better than MDC in all the experiments,
and optimum efficiency was attained at 4000 mg/L anode substrate concentration and
25 g/L salt concentration. PMDC achieved an average working voltage of 354 mV,
90.5% anode COD removal, and 27% desalination, which was 38.1%, 7.5%, and 17.4%
higher than MDC at 4000 mg/L. Moreover, using 25 g/L salt concentration yielded an
average working voltage of 354 mV, 90.5% anode COD removal, and 27% desalination
in PMDC, which was 38.1%, 7.5%, and 17.4% higher than MDC. Furthermore, the
PMDC system offers the additional benefits of nutrient removal and biomass
production at the cathode chamber. These findings proved that, PMDCs outperformed
MDCs in treatment efficiency, power generation, and desalination, making them a
sustainable treatment option.
