Determination of uptake rate of phosphorus and changes in COD and BOD during photoautotrophic cultivation of microalgae in sewage effluent

Photosynthetic organisms like microalgae possess useful potentials such as nutrient uptake, biological oxygen demand (BOD) and chemical oxygen demand (COD) removal from wastewater which are crucial for wastewater treatment. This study was conducted to determine the rate of phosphorus uptake and changes in COD and BOD during microalgae cultivation in sewage effluent.  Standard Methods for the Examination of Water and Wastewater were used to analyse the characteristics of the effluent samples (test), BG-11 medium (control) and also determine algal growth rates under continuous light illumination and constant aeration at varying temperatures. Results obtained showed that; removal efficiencies of Chlorella sp were higher in the test samples than control. Removal efficiencies for BOD, COD and PO4^3- were 92.8%, 59.6% and 61.8% respectively for the test samples and 39.8%, 41.7% and 28.2% for the control. Also, Chlorella sp demonstrated better removal efficiencies at higher growth rates, exponential growth phase, constant aeration and temperature range between 25-30oC. Hence, microalgae, under controlled and optimal conditions can be efficient in removal of pollutants in wastewater (sewage effluent).