Sustainably Cultivating and Harvesting Microalgae through Sedimentation and Forward Osmosis Using Wastes

Hannah R Molitor; Alyssa K Schaeffer; Jerald L Schnoor

doi:10.1021/acsomega.1c01474

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Sustainably Cultivating and Harvesting Microalgae through Sedimentation and Forward Osmosis Using Wastes

Journal article

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Sustainably Cultivating and Harvesting Microalgae through Sedimentation and Forward Osmosis Using Wastes

Hannah R Molitor, Alyssa K Schaeffer and Jerald L Schnoor

ACS omega, Vol.6(27), pp.17362-17371

06/25/2021

DOI: 10.1021/acsomega.1c01474

PMCID: PMC8280685

PMID: 34278122

Appears in UI Libraries Support Open Access

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Abstract

Cost-effective nutrient sources and dewatering are major obstacles to sustainable, scaled-up cultivation of microalgae. Employing waste resources as sources of nutrients offsets costs for nutrient supplies while adding value through simultaneous waste treatment. Forward osmosis (FO), using simulated reverse osmosis brine, is a low-energy membrane technology that can be employed to efficiently harvest microalgae from a dilute solution. In this study, Scenedesmus obliquus, a green microalga, was cultivated with a fertilizer plant wastewater formula and simulated coal-fired power plant flue gas and then separated through either FO, with reverse osmosis reject model water as the draw solution, or sedimentation. Microalgal batches grown with simulated wastewater removed NH4+ within 2 days and reached nitrogen and phosphorus limitation simultaneously on Day 5. Sparging with the flue gas caused S. obliquus to produce significantly greater quantities of extracellular polymeric substances (30.7 ± 1.8 μg mL–1), which caused flocculation and enhanced settling to an advantageous extent. Five-hour FO trials showed no statistically significant difference (p = 0.65) between water fluxes for cultures grown with simulated flue gas and CO2-supplemented air (3.0 ± 0.1 and 3.0 ± 0.3 LMH, respectively). Reverse salt fluxes were low for all conditions and, remarkably, the rate of reverse salt flux was −1.9 ± 0.6 gMH when the FO feed was culture grown with simulated flue gas. In this work, S. obliquus was cultivated and harvested with potential waste resources.

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Title: Subtitle: Sustainably Cultivating and Harvesting Microalgae through Sedimentation and Forward Osmosis Using Wastes
Creators: Hannah R Molitor - Department of Civil and Environmental Engineering, University of Iowa, 103 S. Capitol Street, Iowa City, Iowa 52242, United States
Alyssa K Schaeffer - Department of Civil and Environmental Engineering, University of Iowa, 103 S. Capitol Street, Iowa City, Iowa 52242, United States
Jerald L Schnoor - Department of Civil and Environmental Engineering, University of Iowa, 103 S. Capitol Street, Iowa City, Iowa 52242, United States
Resource Type: Journal article
Publication Details: ACS omega, Vol.6(27), pp.17362-17371
DOI: 10.1021/acsomega.1c01474
PMID: 34278122
PMCID: PMC8280685
NLM abbreviation: ACS Omega
ISSN: 2470-1343
eISSN: 2470-1343
Publisher: American Chemical Society
Grant note: DOI: 10.13039/100000082, name: Division of Graduate Education, award: 1546595; DOI: 10.13039/100008893, name: University of Iowa; DOI: 10.13039/100005740, name: Iowa Space Grant Consortium, award: 80NSSC20M0107; name: Center for Advancement, University of Iowa
Language: English
Date published: 06/25/2021
Academic Unit: Civil and Environmental Engineering; Occupational and Environmental Health
Record Identifier: 9984095142502771

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