Efficient recovery of nitrate and phosphate from wastewater by an amine-grafted adsorbent for cyanobacterial biomass production.

ABSTRACT

Various types of wastewater have been widely utilized in microalgae and cyanobacteria cultivation for environmental and economic reasons. However, the problems of low cell growth and biomass contamination due to direct use of wastewater remain unresolved. In the present study, nitrate and phosphate were separated from wastewater by adsorption and subsequently used for cyanobacterial biomass production. To this end, an amine-grafted magnetic absorbent was synthesized. The synthesized absorbent recovered ca. 78% nitrate and 93% phosphate from wastewater. Regenerated medium was prepared using recovered nutrients as nitrogen and phosphate sources, which were efficiently assimilated by cyanobacterial culture. Compared to synthetic medium, there was no difference in growth and nutrient removal using regenerated medium. The proposed indirect method of wastewater utilization would prevent contamination of the produced biomass by unfavorable substances, which will broaden its potential applications.