Volume 42, Issue 4 e13070
ORIGINAL ARTICLE

Evaluation of the efficacy of subcritical water to enhance the lipid fraction from activated sludge for biodiesel and oleochemicals production

Ifeanyichukwu Edeh

Corresponding Author

Ifeanyichukwu Edeh

School of Chemical Engineering, University of Birmingham, Birmingham, UK

Correspondence

Ifeanyichukwu Edeh, University of Port Harcourt, East-West Road, P.M.B. 5323, Choba, Port Harcourt, Rivers State, Nigeria.

Email: [email protected]

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Tim Overton

Tim Overton

School of Chemical Engineering, University of Birmingham, Birmingham, UK

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Steve Bowra

Steve Bowra

Research and Experimental Developments on Biotechnology, Phytatec (Ltd), Aberystwyth, Ceredigion, UK

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First published: 22 April 2019
Citations: 5

Funding information Petroleum Technology Development Fund

Abstract

Activated sludge is currently being investigated as a potential feedstock to produce biodiesel. Reports have shown that its lipid yield is usually low, compared to the commercially available feedstocks, such as soybean, sunflower, and rapeseed oils. The current work is geared toward investigating the potential of enhancing the total lipid yield (neutral and phospholipid) by the application of subcritical water. The results show that subcritical water treatment increased the total lipid yield by 145% at the optimum conditions 280°C, 40 min, 15 mL of water and biomass loading of 5%. The lipid classes identified were waxes, acylglycerol, sterol, free fatty acid, and phospholipids. The results of the fatty acid methyl esters analysis revealed palmitic acid as the predominant fatty acid.

Practical applications

The practical applications of the results are informed from the improved lipid yield obtained, suggesting that subcritical water treatment is essential if activated sludge were to be a viable feedstock for biodiesel, renewable diesel, and oleochemicals productions. This will serve as a sustainable activated sludge disposal strategy.

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