Use of secondary sewage water as a culture medium for Chaetoceros gracilis and Thalassiosira Sp (Chrysophyceae) in laboratory conditions

• Published in: Brazilian archives of biology and technology Vol. 42; no. 2
• Main Authors: Rauquírio André Albuquerque Marinho da Costa, Maria Luise Koening, Sílvio José de Macêdo
• Format: Journal Article
• Language: English
• Published: Instituto de Tecnologia do Paraná (Tecpar) 01-01-1999
• Subjects: Culture; Microalgae (Chrysophyceae); Secondary sewage
• ISSN: 1516-8913; 1678-4324
• DOI: 10.1590/S1516-89131999000200011

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 10³ cells/ml for Thalassiosira sp on the fifth day. Biomass was higher in the nutritive medium f2 than in the other treatments, reaching average values of 2,363μg/ml for Chaetoceros gracilis. At all experimental units, the best results were registered at 40% addition for Chaetoceros gracilis, where average values of 0.768μg/ml were observed on the fifth day, and at 30% additions for Thalassiosira sp where 0.883μg/ml were observed on the thirteenth day. It was concluded that secondary sewage could be used as a culture medium for the species tested here, after large scale tests.