Comparing the use of different domestic wastewaters for coupling microalgal production and nutrient removal

Abstract

The streams from municipal wastewater treatment plants (WWTP) have been considered a valuable medium for mass cultivation of algal biomass. The aim of this work is to test and compare the performance of Chlorella vulgaris on several streams from five stages, from two different WWTP. The results showed biomass yields ranging from 39 to 195 mg dry-weight l 1 days 1. The best performance as biomass production was obtained with the centrate (effluent from drying the anaerobic sludge). After testing a wide range of N/P ratios with centrate, the highest productivity and growth rates were obtained with the original N/P ratio (2.0) of this stream. The highest removal rates were of 9.8 (N) and 3.0 (P) mg l 1 - days 1, in the centrate. Finally, this research also suggests that microalgal production seems to be a promising process when coupled to wastewater treatment.