Evaluating the performance of Microbial Desalination Cells subjected to different operating temperatures

Abstract

Operational conditions have a tremendous effect on the performance of Microbial Desalination Cells (MDCs). In this study, MDCs were tested at three different temperatures zones; 45, 27 and 12 °C. Average COD removal efficiencies were 78 ± 5, 80 ± 6 and 46 ± 10% at 45, 27, and 12 °C, respectively and the average desalination efficiencies were 22.7 ± 5.8, 17.5 ± 5 and 9.4 ± 4.3% respectively. High columbic efficiencies were obtained of 9.7% at 45 °C and 11.28% at 27 °C, compared with a significantly lower value of 1.04% at 12 °C. Higher columbic efficiencies were correlated to lower COD removal rates. The increase in temperature resulted in a reduction in the internal resistance which improves the desalination. The maximum current densities of 402, 407 and 31 mA/m2 were recorded at 45, 27 and 12 °C respectively. Higher current densities were attained at both 45 and 27 °C while the cell operated at 27 °C only achieved sustained stable densities. The results of microbial community qualification indicated prevalence of three common strains at the three cells and a selective strain at each temperature zone. Scanning electron microscopy results revealed colour changes and distortion of the membranes. This study demonstrated that the MDCs are adaptable to function at different operation temperatures.