Batch kinetics of nitrogen and phosphorus removal from synthetic wastewater by algae

Abstract

Batch experiments were carried out to investigate the effect of the initial nitrogen and phosphorus concentrations on nutrient removal performance of microalgae Chlorella vulgaris and to determine biokinetic coefficients such as k; reaction rate constant, Km, half saturation constant, and Y, yield coefficient by using Michaelis-Menten rate expression. The NH4-N concentration was varied between 13.2-410 mg l-1 while PO4-P concentration was between 7.7-199 mg l-1 by keeping N/P ratio around 2/1 in the synthetic wastewater. The experiments were performed at pH 7.0 and at room temperature (20 ± 2 °C) with artificial illumination (4100 lux). Experimental results indicated that effluent water quality decreases with increasing nutrient concentrations and algae culture can remove nitrogen more effectively compared to phosphorus. Biokinetic coefficients were determined as k = 1.5 mg NH4-N mg-1 chl a d-1, Km = 31.5 mg l-1, YN = 0.15 mg chl a mg-1 NH4-N for nitrogen and k = 0.5 mg PO4-P mg-1 chl a d-1, Km = 10.5 mg l-1, YP = 0.14 mg chl a mg-1 PO4-P for phosphorus. © 2006 Elsevier B.V. All rights reserved.