Growth Kinetics and Nutrient Uptake of Microalgae in Urban Wastewaters with Different Treatment Levels

Abstract

The main objective of this work was to study the speed of growth and nitrogen and phosphorus uptake in a bloom of cultured microalgae in urban wastewater receiving different levels and types of treatment. To this end, microalgae were cultured in duplicate with discontinuity under controlled temperature, light and aeration conditions. Four test media were used consisting of four wastewater effluents: (1) pretreatment, (2) secondary clarifier, (3) UASB bioreactor (Upflow Anaerobic Sludge Blanket) and (4) mixture of UASB and secondary wastewater. All were obtained from the same urban wastewater treatment station. Verhulst and Photobiotreatment models were used to analyze the results. The study found different temporal evolutions of the biomass concentration and total dissolved N and P with the different media tested. Productivity was greater in tests with water from the UASB reactor (0.094 g SS l(-1) d(-1)). In this culture medium, the speed at which nitrogen was removed was similar to the rest of the wastewater tested while phosphorus removal was slower than the other media studied.