Removal of Nitrate and Orthophosphate from Stream Wastewater by Native Microalgal Consortia

Abstract

The aim of this study was to evaluate in vitro the capacity of microalgal consortia to remediate nitrates and orthophosphates. The strains used corresponded to the genomic bank of the Microbiological Research Laboratory of the University of Sucre, Colombia. The microbial strains were bioaugmented to use the concentration of 10⁴ cells/mL, in phycoreactor inoculated with 4 strains of microalgae using a treatment of wastewater from a stream inoculated with microalgal consortium and another control with wastewater without microalgal consortium. Nitrate and orthophosphate concentrations were measured pre- and post-treatment. The triplicate amount test performs five evaluations: one in pre-treatment and four in post-treatment (5,10,15 and 20 days). The results show that each strain of microalgae presents similar growth behaviour and higher for the strain Chlorella vulgaris with respect to Scedesmus sp. In the phyco-remediation test, it was found that the nitrate removal rate was higher than 87% 10 days after the start of the test, while the removal of orthophostates was higher than 100% 10 days after the consortium was inoculated in the wastewater. The control results show an increase of these two compounds from day 10, which infers the importance of microalgae for wastewater treatment.