Contrast Research on Removal of Phosphorous and Nitrogen by Immobilized and Free Chlorella Vulgaris as well as the Metal Cadmium on the Absorption Rate of Phosphorous

Researching on immobilized and free cell cultures,the experimental results showed that immobilized chlorella vulgar has higher removal efficiency to NH4+-N and PO43——P than free cell in two days,it is more than 22.49% of NH4+-N and 35.25% of PO43——P which are removed by immobilized chlorella.The merit of free algae is kept in the immobilized algae,and immobilization improves the removal of nitrogen and phosphorus,protects the algae cells,it can increase the cell life and promotes the absorption of phosphorous and nitrogen.In addition,researching on the rate of absorption of phosphorus which compared the immobilized state with the free one in different light intensities and different pH,the results showed that under different light intensities,cadmium reduces the absorption rate of phosphorus,in most pH,whether in fixed or suspended state,cadmium can only reduce the absorption rate of phosphorus by 20% ~ 30%,so setting treatment does not reduce the impact of cadmium.