Abstract
The microalga Scenedesntus sp. was grown in artificial wastewater with 30 and 50% daily replacements of the culture volume
and under continuous lighting. The biomass per unit volume was higher with the 30% dilution, but daily yields were better with
50%. In 24 h, phosphate removal was more than 50% in both cases. The total nitrogen removed, most of which was ammonia,
was approximately 50 and 66% of the initial concentration for the 30 and 50% dihltions, respectively, and a nitrogen budget
calculated using the total daily removal and the average algal protein harvested gave an imbalance of close to 65 and 75%,
showing that ammonia stripping due to high pH values and aeration might play an important role in the biological tertiary
treatment of wastewater with photosynthetic organisms. Q 1998 Elsevier Science Ltd. All rights reserved.