Comparison of nutrient removal capacity and biomass settleability of four high-potential microalgal species

Abstract

Four common used microalgae species were compared in terms of settleability, nutrient removal capacity and biomass productivity. After 1month training, except cyanobacteria Phormidium sp., three green microalgae species, Chlamydomonas reinhardtii, Chlorella vulgaris and Scenedesmus rubescens, showed good settleability. The N and P removal efficiency was all above 99% within 7, 4, 6 and 6days for N and 4, 2, 3 and 4days for P, resulting in the N removal rates of 3.66±0.17, 6.39±0.20, 4.39±0.06 and 4.31±0.18mgN/l/d and P removal rates of 0.56±0.07, 0.89±0.05, 0.76±0.09 and 0.60±0.05mg P/l/d for Phormidium sp., C. reinhardtii, C. vulgaris and S. rubescens, respectively. Phormidium sp. had the lowest algal biomass productivity (2.71±0.7g/m2/d) and the other three green microalgae showed higher algal biomass productivity (around 6g/m2/d). Assimilation into biomass was the main removal mechanism for N and P.