Drs. Lu and Johnson both presented at IABBB 2019 meeting in Boulder CO.
Implementation of UV-based advanced oxidation processes in algal medium reuse
Z. Lu, W. Wang, J. Sha, X. Zhang, P. Sun, Q. Hu
Algae show great potential as sustainable feedstock for numerous bioproducts. However, large volume of water consumption during algal biomass production make the culture media recycling is a necessity due to economic and environmental concern. To avoid the negative effect of enriched organic matters in the harvested culture media, pre-treatment prior to medium replenishment and reuse is required. In this study, degradation of algenitic organic matters (AOM) in the culture media by UV-based photolysis processes (i.e., direct UV, UV/peroxydisulfate (PDS), UV/H2O2 and UV/NH2Cl) was explored. The results showed that UV, UV/ PDS, UV/H2O2 and UV/NH2Cl caused a decrease of SUVA for 29.9%, 35.4%, 40.45% and 22.6%, respectively, though the organic matter was almost not mineralized. Fluorescence excitation-emission matrix combined with parallel factor analysis indicated that UV/ PDS and UV/H2O2 degraded 47.26%-56.31% of the fluvic-like and humic-like fractions in AOM. Powder activated carbon absorption and growth evaluation for the AOPs-treated media indicated that UV/ PDS and UV/H2O2 processes not only could remove the growth inhibitors in the media, but also were beneficial to the algae growth. These results suggested that UV/PDS and UV/H2O2 could effectively degradation the hydrophobic components in AOM and converted the growth inhibition fraction of AOM in the recycled media into nutrient source for algal growth. Unlike the general application of UV-based AOP in the wastewater treatment, this study provided an innovative idea about how to pre-treat AOM in the media recycling: utilization rather than removal, which was a more sustainable and environment-friendly technology.
Algae production from the Marine Algae Industrialization Consortium (MAGIC)
Z. Johnson
Duke University, USA
Introduction: The Marine Algae Industrialization Consortium (MAGIC) is a group of academic and private institutions that together seek to advance the large scale use of marine algae for the sustainable production of food, feed and fuel. Our team is an integrated pipeline from algae strain selection to production, separation, product assessment and economic and life cycle analyses. Here we present results and interpretation from the outdoor cultivation and harvesting of several top candidate strains. Methods: Numerous taxonomically diverse strains of marine microalgae were grown in outdoor raceway ponds across an annual cycle to investigate factors that lead to enhanced production and recovery of algae biomass for downstream applications. These marine microalgae were grown in a hybrid PBR – raceway pond system that experienced natural environmental variability and thus the range of values recovered represent a real world assessment of production. Results: We show that there is a dramatic variability in the productivity across taxa, environmental conditions, and pond operational parameters with some combinations leading to substantial improvements over ‘standard’ conditions in overall biomass yields. Discussion: These results demonstrate the variability across strains/conditions and the importance of using industrially relevant conditions when design testing infrastructure and operational conditions. The best combinations suggest areas that may be further optimized for future increases in algae productivity. Finally, the biomass generated has excellent biochemical characteristics that support an improved economic assessment of the use of marine algae for the sustainable production of fuel, feed and food.
