Algal biofuels from urban wastewaters: Maximizing biomass yield using nutrients recycled from hydrothermal processing of biomass. (April 2015)

• Record Type: Journal Article
• Authors: Selvaratnam, T.; Pegallapati, A.K.; Reddy, H.; Kanapathipillai, N.; Nirmalakhandan, N.; Deng, S.; Lammers, P.J.
• Is Part Of: Bioresource technology. Volume 182(2015)
• Page Start: 232
• Page End: 238
• Publication Date: 2015-04
• Subjects: Algal bioenergy -- Wastewater treatment -- Hydrothermal liquefaction -- Regrowth in recycled nutrients -- Galdieria sulphuraria; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2015.01.134
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Highlights: Demonstrated higher biomass growth in wastewater than in control. Demonstrated >90% nutrient removal from wastewater. Evaluated biomass growth in aqueous product obtained at six HTL-temperatures. Demonstrated higher biomass productivity in aqueous product of HTL. Abstract: Recent studies have proposed algal cultivation in urban wastewaters for the dual purpose of waste treatment and bioenergy production from the resulting biomass. This study proposes an enhancement to this approach that integrates cultivation of an acidophilic strain, Galdieria sulphuraria 5587.1, in a closed photobioreactor (PBR); hydrothermal liquefaction (HTL) of the wet algal biomass; and recirculation of the nutrient-rich aqueous product (AP) of HTL to the PBR to achieve higher biomass productivity than that could be achieved with raw wastewater. The premise is that recycling nutrients in the AP can maintain optimal C, N and P levels in the PBR to maximize biomass growth to increase energy returns. Growth studies on the test species validated growth on AP derived from HTL at temperatures from 180 to 300 °C. Doubling N and P concentrations over normal levels in wastewater resulted in biomass productivity gains of 20–25% while N and P removal rates also doubled.