| Chlamydomonas reinhardti was employed to remove nitrogen and phosphorus from wastewater. The effects of initial NH+4-N and TP concentrations, N/P ratios, Light/Darkness ratios, pH and immobilization on the removal of NH+4-N and TP were evaluated. The results showed that C. reinhardti could almost 100% remove NH+4-N and TP as initial concentrations of NH+4-N and TP were no more than 55 mg·L-1 and 7 mg·L-1, respectively, whereas the removal ratio of NH+4-N decreased drastically to 50% with initial NH+4-N concentration coming up to 75 mg·L-1. Under N/P ratios of 5∶1 and 10∶1, C. reinhardti could completely remove NH+4-N within 3d, while 6 d was needed with N/P ratio being 25∶1. Different from NH+4-N removal, the removal ratio of TP could reach almost 100% within 4 d under 3 N/P ratios. With L/D ratios of 24 h∶0 h and 12 h∶12 h, 100% removal of NH+4-N and TP could be achieved by C. reinhardti, but the removal rate under L/D ratio of 24 h∶0 h was relatively faster. The optimal pH range for C. reinhardti to remove NH+4-N and TP was 6-7. After immobilization, the ability of C. reinhardti to remove NH+4-N was significantly enhanced as the removal ratio of NH+4-N came up to 100% with initial NH+4-N concentration being 75 mg·L-1. The ability of immobilized C. reinhardti to remove TP kept stable, whereas the removal rate was slowed slightly. |
