The present investigation focuses on the bioremediation of waste water by using various microalgae like Scenedesmus dimorphus, Oscillatoria willei, Chroococcus minutus and Lyngbya confervoides. For the study the industrial waste water samples and algal samples were collected from Kayamkulam Lake near NTPC, Alappuzha district, Kerala. Water samples were analysed for 12 Physico- Chemical parameters such as pH, Alkalinity, DO, Chloride, Total Hardness, Calcium, Phosphate, Sulphate, Nitrate, BOD, COD, Silicate and Heavy metals using standard methods. Algae were analysed quantitatively and qualitatively. Four most abundant and pollution tolerant taxa were isolated from the effluent and cultured in BBM and ATCC growth media. These cultures are used for the bioremediation of the above mentioned Physico-chemical parameters. The percentage reduction of each parameter was recorded from the samples treated with these algae. The percentage reduction attained with S. dimorphus was Alkalinity (46%), Phosphate (86.14%), Nitrate (77.64%), Sulphate (33.16%), Chloride (56%), Iron (42.8%), COD (71.23%) and BOD (89.72%). In case of O. willei, the percentage reduction observed was Alkalinity (49%), Phosphate (79%), Nitrate (71%), Sulphate (66.7%), Silicate (72%), Iron (53%), COD (76%) and BOD (66%). The percentage reduction with the treatment of L.confervoides was Alkalinity (43%), Phosphate (77%), Nitrate (71%), Sulphate (59.6%), COD (68%) and BOD (62%) and in case of C. minutus, the reduction noticed was Alkalinity (56%), Phosphate (92%), Nitrate (68%), Sulphate (52.9%), Silicate (89%), Chloride (52%), COD (51%) and BOD (52%) The results were discussed in the text.