This study investigated the feasibility of using recovered nutrients from hydrothermal carbonization (HTC) for cultivation of microalga Chlorella vulgaris. Different dilution multiples of 50, 100 and 200 were applied to the recycled process water from HTC and algal growth was compared among these media and a standard growth medium BG-11. Algae achieved a biomass concentration of 0.79 g/L on 50× process water after 4 days. Algae removed total nitrogen, total phosphorus and chemical oxygen demand by 45.5-59.9%, 85.8-94.6% and 50.0-60.9%, respectively, on differently diluted process water. The fatty acid methyl ester yields for algae grown on the process water were 11.2% (50×), 11.2% (100×) and 9.7% (200×), which were significantly higher than 4.5% for BG-11. In addition, algae cultivated on process water had 18.9% higher carbon and 7.8% lower nitrogen contents than those on BG-11, indicating that they are very suitable as biofuel feedstocks.
Bibliographical noteFunding Information:
The work reported here was supported in part by grants from Minnesota Legislative-Citizen Commission on Minnesota Resources (LCCMR), University of Minnesota Initiative for Renewable Energy and Environment (IREE) and Center for Biorefining, and Ministry of Science and Technology (MOST) in China.
Copyright 2017 Elsevier B.V., All rights reserved.
- Hydrothermal carbonization
- Nutrient recycling