Comparison of the efficiency of sodium nitrate and superphosphate as nutrients in the bioremediation of petroleum hydrocarbon polluted water

The effect of Aspergillus Niger stimulated with 0.2M sodium nitrate and 0.2M single superphosphate fertilizer (nutrients) was investigated in this study. The ambient temperature averaged 29oC all through the 25 days of the research. The comparison was done using three setups- two samples of the hydrocarbon polluted water were amended with the nutrients and with Aspergillus Niger. The third sample served as control. After twenty five days, it was observed that the sample amended with 0.2M sodium nitrate went through the highest amount of bioremediation: For the total hydrocarbon content, the sample with 0.2M sodium nitrate in it dropped by 78.62% (393 – 84mg/L), the sample with 0.2M superphosphate in it - 72.5% (393 – 108mg/L) and the control sample with the lowest drop of 52.16% (393 – 188mg/L). For the biological oxygen demand, the sample with 0.2M sodium nitrate in it dropped by 71.60% (1832.6 – 520.47), the sample with 0.2M superphosphate in it dropped by 63.37% (1832.6 – 671.3mg/L) and the control sample had the lowest drop of 50.27% (1832.6 – 911.29mg/L). The pH of the samples with nutrients in them were initially acidic but became less acidic with time while the control sample which was initially neutral became more acidic