Influence of cerium oxide nanoparticles on dairy effluent nitrate and phosphate bioremediation

This study investigated, for the first time, the role of cerium oxide nanoparticles (CeO 2 NPs) on dairy effluent nitrate and phosphate bioremediation using different inoculum sources. Two inoculum sources (wastewater and sludge) were obtained from the dairy wastewater treatment plant unit. A culture was prepared to be tested in the treatment of nitrate and phosphate effluent, and the role of CeO 2 NPs was checked to be completely efficient after 5 days of incubation. The reduction efficiency of nitrate using sludge as inoculum source was improved up to 89.01% and 68.12% for phosphate compared to control. In the case of using wastewater as an inoculum source, the nitrate reduction was improved up to 83.30% and 87.75% for phosphate compared to control. The bacterial richness showed a significant variance (higher richness) between control and other samples. The optimal concentration of CeO 2 NPs for inoculum richness and nitrate and phosphate reduction was (sludge: 1 × 10 −10 ppm) and (wastewater: 1 × 10 −12 ppm). The results revealed that CeO 2 NPs could enhance the microbial growth of different inoculum sources that have a key role in dairy effluent nitrate and phosphate bioremediation.