PHYCOREMEDIATION OF HEAVY METALS IN POLLUTED WATER BODIES

Phycoremediation is the process in which algae are employed to cleanup the environment. Blue Green Algae (BGA) are ideally suitable to play a dual role of treating wastewater in the process of effective utilization of different constituents essential for growth leading to enhanced biomass production. The algal isolates (Anabaena variabilis, Aulosira sp., Nostoc muscorum, Oscillatoria sp. and Westiellopsis sp.) were grown in 100% effluent supplemented with and without basal nutrients and in Siruvani water as control. Results on the growth response of the BGA in wastewater shows that the algae can grow very well in polluted water. Among the tested isolates Anabaena variabilis performed well for biosorbing the heavy metals. In control Anabaena variabilis recorded the mean biomass (Oven dry weight) of 5.54 g L1, maximum biomass production in the presence and absence of basal nutrients were 12.47 and 10.69g L-1 respectively. During 7th day the mean biomass was 2.94g L-1 , 6.45 g L-1, 5.30g L-1 and at 28th day 5.71g L,-1 11.93 g L-1 and 9.66 g L-1 in control, medium supplemented with and with out basal nutrients respectively. The mean available Cr, Cd, Ni and Pb were reduced to 0.67, 0.57, 1.72 and 1.32 ppm respectively by Anabaena variabilis in 28 days. During 7 th day the available Cr, Cd, Ni and Pb concentrations were 1.23, 1.33, 3.15 and 2.59 ppm respectively, while at 28 th day 100% reduction of heavy metals was noticed in all the treatments. The algae were also able to completely remove the offensive odour of the effluent.