title: Microalgal bacterial flocs treating paper mill effluent: A sunlight-based approach for removing carbon, nitrogen, phosphorus, and calcium.
abstract: Treatment of upflow anaerobic sludge blanket (UASB) effluent from a paper mill in aerated activated sludge reactors involves high aeration costs. Moreover, this calcium-rich effluent leads to problematic scale formation. Therefore, a novel strategy for the aerobic treatment of paper mill UASB effluent in microalgal bacterial floc sequencing batch reactors (MaB-floc SBRs) is proposed, in which oxygen is provided via photosynthesis, and calcium is removed via bio-mineralization. Based on the results of batch experiments in the course of this study, a MaB-floc SBR was operated at an initial neutral pH. This SBR removed 58±21% organic carbon, 27±8% inorganic carbon, 77±5% nitrogen, 73±2% phosphorus, and 27±11% calcium. MaB-flocs contained 10±3% calcium, including biologically-influenced calcite crystals. The removal of calcium and inorganic carbon by MaB-flocs significantly decreased when inhibiting extracellular carbonic anhydrase (CA), an enzyme that catalyses the hydration and dehydration of CO2. This study demonstrates the potential of MaB-floc SBRs for the alternative treatment of calcium-rich paper mill effluent, and highlights the importance of extracellular CA in this treatment process.
authors.affiliation: Center for Microbial Ecology and Technology (CMET), Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Gent, Belgium(2); Laboratory of Industrial Water and Eco-Technology (LIWET), Faculty of Bioscience Engineering, Ghent University, Graaf Karel de Goedelaan 5, B-8500 Kortrijk, Belgium(3); ESPOL Polytechnic University, Escuela Superior Politécnica del Litoral, ESPOL, Centro Nacional de Acuicultura e Investigaciones Marinas (CENAIM), Campus Gustavo Galindo, Km. 30.5 Vía Perimetral, P.O. Box 09-01-5863, Guayaquil, Ecuador(4); ESPOL Polytechnic University, Escuela Superior Politécnica del Litoral, ESPOL, Facultad de Ciencias de la Vida, Campus Gustavo Galindo, Km. 30.5 Vía Perimetral, P.O. Box 09-01-5863, Guayaquil, Ecuador(5). Electronic address: shende@espol.edu.ec.
authors.forename: Sofie
authors.initials: S
authors.lastname: Van Den Hende
authors.affiliation: Laboratory of Industrial Water and Eco-Technology (LIWET), Faculty of Bioscience Engineering, Ghent University, Graaf Karel de Goedelaan 5, B-8500 Kortrijk, Belgium(3); Centre for the Study of Education, Technologies and Health (CSETH), Polytechnic Institute of Viseu, Av. J. M. Vale de Andrade, 3504-510 Viseu, Portugal(6). Electronic address: andre.rodrigues@estv.ipt.pt.
authors.forename: André
authors.initials: A
authors.lastname: Rodrigues
authors.affiliation: Earth and Environmental Sciences, KU Leuven, Celestijnenlaan 200E, B-3001 Heverlee, Belgium(7). Electronic address: helen.hamaekers@ees.kuleuven.be.
authors.forename: Helen
authors.initials: H
authors.lastname: Hamaekers
authors.affiliation: ESPOL Polytechnic University, Escuela Superior Politécnica del Litoral, ESPOL, Centro Nacional de Acuicultura e Investigaciones Marinas (CENAIM), Campus Gustavo Galindo, Km. 30.5 Vía Perimetral, P.O. Box 09-01-5863, Guayaquil, Ecuador(4). Electronic address: ssonnen@espol.edu.ec.
authors.forename: Stanislaus
authors.initials: S
authors.lastname: Sonnenholzner
authors.affiliation: Laboratory of Industrial Water and Eco-Technology (LIWET), Faculty of Bioscience Engineering, Ghent University, Graaf Karel de Goedelaan 5, B-8500 Kortrijk, Belgium(3); Centre for Advanced Process Technology for Urban Resources (CAPTURE), Ghent University, Coupure Links 653, B-9000 Gent, Belgium(8). Electronic address: Han.Vervaeren@UGent.be.
authors.forename: Han
authors.initials: H
authors.lastname: Vervaeren
authors.affiliation: Center for Microbial Ecology and Technology (CMET), Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Gent, Belgium(2). Electronic address: Nico.Boon@UGent.be.
authors.forename: Nico
authors.initials: N
authors.lastname: Boon
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D061249:Batch Cell Culture Techniques; D001673:Biodegradation, Environmental; D019149:Bioreactors / Q000382:microbiology; D002118:Calcium / Q000302:isolation & purification; D002119:Calcium Carbonate / Q000737:chemistry; D002244:Carbon / Q000302:isolation & purification; D057486:Carbon Cycle; D002256:Carbonic Anhydrases / Q000378:metabolism; D011232:Chemical Precipitation; D005427:Flocculation; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste / Q000032:analysis*; D058086:Microalgae / Q000378:metabolism*; D009584:Nitrogen / Q000302:isolation & purification; D010209:Paper; D010758:Phosphorus / Q000302:isolation & purification; D013472:Sunlight; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*; D014961:X-Ray Diffraction
chemical_list: D007220:Industrial Waste; D014874:Water Pollutants, Chemical; D010758:Phosphorus; D002244:Carbon; D002256:Carbonic Anhydrases; D002119:Calcium Carbonate; D009584:Nitrogen; D002118:Calcium
keywords: Algae; Calcite; Carbonic anhydrase; Paper mill; Wastewater