Effects of copper at different pH on the nitrogen-removal efficiencies of immobilized Chlorella pyrenoidosa.

The static simulation test for synthetic wastewater purification was carried out by using Chlorella pyrenoidosa entrapped in calcium alginate,and influence of copper at different pH on the nitrogen-removal efficiencies of immobilized Chlorella pyrenoidosa for ammonia and nitric acid-containing wastewater were also investigated.Test results showed that comparing without copper in wastewater,when copper was added,the NH+3-N removal of immobilized Chlorella pyrenoidosa in 5 days at pH=4,5,6,7,8 was reduced 4.0%,0.6%,5.9%,6.0% and 4.4% respectively,the NH+3-N removal of suspended Chlorella pyrenoidosa was reduced 10.9%,22.4%,15.5%,14.5%,20.2% respectively;The NO-3-N removal of immobilized Chlorella pyrenoidosa at pH=6,7,8 was reduced 4.1%,2.8% and 4.2% respectively,but the NO-3-N removal at pH=4,5 was increased 0.8%,0.2%,the NO-3-N removal of suspended Chlorella pyrenoidosa was reduced 4.4%,9.2%,5.3%,10.6%,10.2% respectively.So copper has inhibited the nitrite uptake efficiency of Chlorella pyrenoidosa in free cells than the immobilized ones,and the treatment of immobilization to algae smoothed the disruption of copper.