Effects of biopellets composed of microalgae and fungi on cadmium present at environmentally relevant levels in water

ABSTRACT

Removal of cadmium (Cd) present at low levels (1 µg L⁻¹) in water was investigated using three different microorganism treatments: the microalga Chlorella vulgaris, the fungus Aspergillus niger, and for the first time biopellets composed of C. vulgaris and A. niger. After 5 days, all microorganism treatments resulted in significantly lower Cd concentrations compared with the control. Biopellets treatment resulted in significantly lower pH values than other microorganism treatments, indicating that the biopellets should be investigated further for their water treatment capacity, since pH is a factor affecting the fate of numerous pollutants in water. Use of biopellets as a method to simplify harvesting of microalgae from water is also suggested.

KEYWORDS:

• cadmium
• biopellets
• microalgae
• fungi
• water treatment

Funding

The authors gratefully acknowledge financial support by the Ångpanneföreningens Research Foundation through grant number 13–397. H. Bodin is also grateful for the encouraging support by Bo Hu at the Department of Bioproducts and Biosystems Engineering, University of Minnesota, USA. M. Hultberg's work was supported by the Vinnova project “The Warm and Clean City 2 (2014–00717).”