Experiments were carried out in order to test the efficiency of additions of secondary sewage as a culture medium for Chaetoceros gracilis and Thalassiosira sp (Chrysophyceae) under laboratory conditions. These algae were cultivated in sea water with concentrations of 10%, 20%, 30% and 40% of wastewater. The results were compared with those obtained by the nutritive medium f2 of Guillard (1975). The best results in terms of cellular densities were observed at 40% additions. There were significant differences (significance levels of 5%) between the nutritive medium f2 and the 40% additions for both the species. Maximum cellular densities observed for all additions tested were, 4,125.00 x 10³ cells/ml for Chaetoceros gracilis on the ninth day and 834.00 x... |