title: An ultra-low energy method for rapidly pre-concentrating microalgae.
abstract: This study demonstrates that Nannochloropsis sp. can be effectively separated from its growth medium (0.2-0.3g/L) using electro-coagulation-flocculation in a 100mL batch reactor with nickel electrodes and a treatment time of only 4s. Minimum energy density input for effective separation is 0.03 kWh/m(3). Both energy input and treatment time are much smaller than reported elsewhere. The process results in rapid separation of microalgae (over 90% in 120 min) with minimal damage to algal cells (>90% still alive after processing). At around 4V input, algae can be effectively separated even in very low concentrations. Pulsing is equally effective in separating microalgae as continuous direct current of same magnitude and total exposure time. Algae can separate from their growth medium even if the suspension itself is not treated, but is mixed with treated saltwater with same conductivity. The described method has significant advantages including applicability to continuous processing and water reuse.
authors.affiliation: Seattle University, 901 12th Ave, P.O. Box 222000, Seattle, WA 98122, USA. Electronic address: teodora@seattleu.edu.
authors.forename: Teodora Rutar
authors.initials: TR
authors.lastname: Shuman
authors.affiliation: Seattle University, 901 12th Ave, P.O. Box 222000, Seattle, WA 98122, USA. Electronic address: mason@seattleu.edu.
authors.forename: Gregory
authors.initials: G
authors.lastname: Mason
authors.affiliation: Seattle University, 901 12th Ave, P.O. Box 222000, Seattle, WA 98122, USA. Electronic address: marsolem@seattleu.edu.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Marsolek
authors.affiliation: Seattle University, 901 12th Ave, P.O. Box 222000, Seattle, WA 98122, USA. Electronic address: liny2@seattleu.edu.
authors.forename: Yizhou
authors.initials: Y
authors.lastname: Lin
authors.affiliation: Seattle University, 901 12th Ave, P.O. Box 222000, Seattle, WA 98122, USA. Electronic address: reeved@seattleu.edu.
authors.forename: Daniel
authors.initials: D
authors.lastname: Reeve
authors.affiliation: Seattle University, 901 12th Ave, P.O. Box 222000, Seattle, WA 98122, USA. Electronic address: schachta@seattleu.edu.
authors.forename: Alexander
authors.initials: A
authors.lastname: Schacht
mesh_terms: D004566:Electrodes; D005427:Flocculation; D058086:Microalgae / Q000378:metabolism*; D009532:Nickel / Q000737:chemistry
chemical_list: D009532:Nickel
keywords: Algae; Dewatering; Electro-coagulation; Flocculation; Separation