Comparing the effect of zinc oxide and titanium dioxide nanoparticles on the ability of moderately halophilic bacteria to treat wastewater.

This study evaluates the ability of moderately halophilic bacterial isolates (Serratia sp., Bacillus sp., Morganella sp., Citrobacter freundii and Lysinibacillus sp.) to treat polluted wastewater in the presence of nZnO and nTiO2 nanoparticles. In this study, bacteria isolates were able to take up nZnO and nTiO2 at concentrations ranging from 1 to 50 mg/L in the presence of higher DO uptake at up to 100% and 99%, respectively, while higher concentrations triggered a significant decrease. Individual halophilic bacteria exhibited a low COD removal efficiency in the presence of both metal oxide nanoparticles concentration ranged between 1 and 10 mg/L. At higher concentrations, they triggered COD release of up to - 60% concentration. Lastly, the test isolates also demonstrated significant nutrient removal efficiency in the following ranges: 23-65% for NO3- and 28-78% for PO43-. This study suggests that moderately halophilic bacteria are good candidates for the bioremediation of highly polluted wastewater containing low metal oxide nanoparticles.