title: Up-scaling aquaculture wastewater treatment by microalgal bacterial flocs: from lab reactors to an outdoor raceway pond.
abstract: Sequencing batch reactors with microalgal bacterial flocs (MaB-floc SBRs) are a novel approach for photosynthetic aerated wastewater treatment based on bioflocculation. To assess their technical potential for aquaculture wastewater treatment in Northwest Europe, MaB-floc SBRs were up-scaled from indoor photobioreactors of 4 L over 40 and 400 L to a 12 m(3) outdoor raceway pond. Scale-up decreased the nutrient removal efficiencies with a factor 1-3 and the volumetric biomass productivities with a factor 10-13. Effluents met current discharge norms, except for nitrite and nitrate. Flue gas sparging was needed to decrease the effluent pH. Outdoor MaB-flocs showed enhanced settling properties and an increased ash and chlorophyll a content. Bioflocculation enabled successful harvesting by gravity settling and dewatering by filtering at 150-250 μm. Optimisation of nitrogen removal and biomass valorisation are future challenges towards industrial implementation of MaB-floc SBRs for aquaculture wastewater treatment.
authors.affiliation: Laboratory for Industrial Water and Eco-Technology (LIWET), Enbichem, Faculty of Bioscience Engineering, Ghent University, Graaf Karel de Goedelaan 5, B-8500 Kortrijk, Belgium; Laboratory of Microbial Ecology and Technology (LabMET), Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Gent, Belgium. Electronic address: sofie.vandenhende@ugent.be.
authors.forename: Sofie
authors.initials: S
authors.lastname: Van Den Hende
authors.affiliation: Laboratory for Industrial Water and Eco-Technology (LIWET), Enbichem, Faculty of Bioscience Engineering, Ghent University, Graaf Karel de Goedelaan 5, B-8500 Kortrijk, Belgium. Electronic address: veerle.beelen@ugent.be.
authors.forename: Veerle
authors.initials: V
authors.lastname: Beelen
authors.affiliation: Laboratory for Industrial Water and Eco-Technology (LIWET), Enbichem, Faculty of Bioscience Engineering, Ghent University, Graaf Karel de Goedelaan 5, B-8500 Kortrijk, Belgium; Ecole des Métiers de l'Environnement (EME), Campus de Ker Lann, Avenue Robert Schuman, F-35170 Bruz, France. Electronic address: gaellebore@ecole-eme.com.
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Bore
authors.affiliation: Laboratory of Microbial Ecology and Technology (LabMET), Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Gent, Belgium. Electronic address: nico.boon@ugent.be.
authors.forename: Nico
authors.initials: N
authors.lastname: Boon
authors.affiliation: Laboratory for Industrial Water and Eco-Technology (LIWET), Enbichem, Faculty of Bioscience Engineering, Ghent University, Graaf Karel de Goedelaan 5, B-8500 Kortrijk, Belgium. Electronic address: han.vervaeren@ugent.be.
authors.forename: Han
authors.initials: H
authors.lastname: Vervaeren
mesh_terms: D017756:Aquaculture; D001419:Bacteria / Q000378:metabolism*; D061249:Batch Cell Culture Techniques / Q000295:instrumentation; D001673:Biodegradation, Environmental; D057919:Biological Oxygen Demand Analysis; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology*; D004553:Electric Conductivity; D005427:Flocculation; D006863:Hydrogen-Ion Concentration; D058086:Microalgae / Q000378:metabolism*; D009584:Nitrogen / Q000032:analysis; D010100:Oxygen / Q000032:analysis; D010758:Phosphorus / Q000032:analysis; D017785:Photons; D010788:Photosynthesis; D061005:Ponds / Q000382:microbiology*; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000737:chemistry* / Q000382:microbiology; D018508:Water Purification / Q000379:methods*
chemical_list: D009584:Nitrogen; D010100:Oxygen; D010758:Phosphorus; D062065:Wastewater
keywords: Algae; Aquaculture wastewater; Bioflocculation; Biomass; Raceway pond