title: Tertiary wastewater treatment in membrane photobioreactor using microalgae: Comparison of forward osmosis & microfiltration.
abstract: Discharge of wastewater with high nitrogen and phosphorus content is a major cause of eutrophication. In this study, a microfiltration-based membrane photobioreactor (MPBR) and forward osmosis-based osmotic membrane photobioreactor (OMPBR) have been operated with Chlorella vulgaris for continuous tertiary wastewater treatment. Both the bioreactors exhibited good biomass accumulation (over 2g/L), although the OMPBR achieved better nutrients removal due to high rejection properties of the membranes. At 2days HRT, the OMPBR achieved nitrogen and phosphorus removal efficiencies of 86-99% and 100%, respectively, whereas the corresponding values in the MPBR were 48-97% and 46%, respectively. Based on the energy input, the total operating costs for OMPBR were 32-45% higher than that of the MPBR, and filtration cost for OMPBR was 3.5-4.5 folds higher than that of the MPBR. These results indicate that the integration of membrane filtration with photobioreactors is promising in microalgae-based tertiary wastewater treatment.
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore.
authors.forename: Prashant
authors.initials: P
authors.lastname: Praveen
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore.
authors.forename: Jonathan Yun Ping
authors.initials: JYP
authors.lastname: Heng
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore. Electronic address: chelohkc@nus.edu.sg.
authors.forename: Kai-Chee
authors.initials: KC
authors.lastname: Loh
mesh_terms: D018533:Biomass; D048408:Chlorella vulgaris / Q000254:growth & development* / Q000378:metabolism; D003365:Costs and Cost Analysis; D004867:Equipment Design; D005374:Filtration / Q000295:instrumentation / Q000379:methods; D008567:Membranes, Artificial; D058086:Microalgae / Q000254:growth & development* / Q000378:metabolism; D009584:Nitrogen / Q000302:isolation & purification; D009995:Osmosis; D010758:Phosphorus / Q000302:isolation & purification; D058433:Photobioreactors / Q000191:economics; D014865:Waste Disposal, Fluid / Q000191:economics / Q000295:instrumentation* / Q000379:methods; D062065:Wastewater / Q000737:chemistry
chemical_list: D008567:Membranes, Artificial; D009584:Nitrogen; D010758:Phosphorus; D062065:Wastewater
keywords: Forward osmosis; Membrane bioreactor; Microalgae; Photobioreactor; Wastewater treatment