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Bio-desalination of brackish and seawater using halophytic algae
Citation:
Sahle-Demessie, Endalkac, A. Hassan, AND A. Badawy. Bio-desalination of brackish and seawater using halophytic algae. DESALINATION. Elsevier Science Ltd, New York, NY, 465:104-113, (2019). https://doi.org/10.1016/j.desal.2019.05.002
Impact/Purpose:
Although desalination by membrane processes, such as reverse osmosis, is a possible solution to the problem of freshwater supply, the related cost and energy demands prohibit its use on a global scale. Hence, there is an emerging necessity for alternative, energy and cost-efficient methods for water desalination. This manuscript explores the possibility of using biological systems for the targeted removal of Na+ and Cl− from seawater. We used halophytic algae that actively grow in vast blooms both in fresh and seawater bodies that allow a cost and energy-efficient desalination. The algae can be used for generating energy. The technology desalinate brackish water, generate renewable energy and sequester carbon dioxide.
Description:
Global demand for water is rising. A sustainable and energy efficient approach is needed to desalinate brackish sources for agricultural and municipal water use. Genetic variation among two algae species, Scenedesmus species (S. sp.) and Chlorella vulgaris (C. vulgaris), in their tolerance and uptake of salt (NaCl) was examined for potential bio-desalination of brackish water. Salt-tolerant hyper-accumulators were evaluated in a batch photobioreactors over salinity concentration ranging from 2 g/L to 20 g/L and different nutrient composition for their growth rate and salt-uptake. During algae growth phase, the doubling time varied between 0.63 and 1.81 days for S. sp. and 3.1 to 5.9 for C. vulgaris. The initial salt-uptake followed pseudo first order kinetics where the rate constant ranged between −3.58 and −7.68 day−1 reaching up to 30% in a single cycle. The halophyte algae S. sp. and C. vulgaris that were selected for pilot-scale studies here represent a promising new method for desalination of brackish waters. Halophytic technologies combined with the potential use of algae for biofuel, which offsets energy demand, can provide a sustainable solution for clean, affordable water and energy.
URLs/Downloads:
DOI: Bio-desalination of brackish and seawater using halophytic algae
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