(762e) Starvation of a Mixed Culture of Chlorella Vulgaris and Scenedesmus Sp. for Enhanced Removal of Ammonia From Wastewater Effluent and Its Impact On Lipids Formation

Bala P. Lingaraju¹, Jinsoo Kim¹, Joo-Youp Lee¹, Zhouyang Liu², Kaniz F. Siddiqui³

¹ Chemical Engineering Program, University of Cincinnati, OH 45221-0012

² Environmental Engineering Program, University of Cincinnati, OH 45221-0012

³ The Metropolitan Sewer District of Greater Cincinnati, Cincinnati, OH 45204-2002

Abstract

Microalgae have proven to have the capability to remove nitrogen and phosphorus from wastewater.  Investigation of a possible synergy between wastewater treatment and renewable energy production was also considered.  However, one of the major barriers against the proposed idea is the slow uptake kinetics.  In our preliminary study, a mixed culture of Chlorella vulgaris and Scenedesmus sp. starved of nitrogen has shown a faster ammonia uptake rate from secondary wastewater effluent.  High density culture and suspended algae has shown faster uptake rate compared to settled algae.  In this study, the residual ammonia uptake kinetics has been investigated in a batch system in terms of initial algal seed density using two different seeds grown under nitrogen-deficient and –sufficient conditions in order to determine an initial algal cell density that can achieve 90% ammonia removal within 48 hours.  The change in lipids content and profile before and after the ammonia uptake has also been analyzed using solvent extraction followed by gas chromatography.  TEM/confocal microscope image analysis and Nile red stain method were also used to validate the change in lipids content.

Keywords: Chlorella vugaris, Wastewater treatment, Ammonia removal, Lipids analysis.