Microalgae as bioabsorbents for treating mixture of electroplating and sewage effluent

The effectiveness of copper and nickel uptake by microalgae grown in the mixture of electroplating effluent and sewage was studied. The results showed that a high percentage of copper removal (68.1%-88.2%) was achieved by Chlorella pyrenoidosa (strain No. 26) reared in the mixture of 90% electroplating effluent and 10% raw sewage during the first 3 days despite the fact that cell growth was inhibited. Similar results were also obtained by using Chlorella HKBC-C3, another species collected from one of the heavy metal polluted sites in Hong Kong, isolated and cultured in the Biology Department. There was no significant difference (P greater than 0.05) in the removal of copper and nickel from the effluent between these 2 algal species. However, it was noted that removal of nickel from the mixture by the two species were comparatively lower (less than 20%) than the removal of copper (greater than 68%).