Title: Innovative blends to wastewater sludge energy valorisation towards a sustainable circular bioeconomy

Authors: Carlos André Silvestre M. De Almeida; Ivo Da Silva; Fernanda S. Peiter; Karina Ribeiro Salomon

Addresses: Centre of Technology, Federal University of Alagoas, Av. Lourival Melo Mota, Maceió, Alagoas, CEP 57072-900, Brazil ' Centre of Technology, Federal University of Alagoas, Av. Lourival Melo Mota, Maceió, Alagoas, CEP 57072-900, Brazil ' Centre of Technology, Federal University of Alagoas, Av. Lourival Melo Mota, Maceió, Alagoas, CEP 57072-900, Brazil ' Centre of Technology, Federal University of Alagoas, Av. Lourival Melo Mota, Maceió, Alagoas, CEP 57072-900, Brazil

Abstract: This work aimed to determine the elementary, chemical and energy characteristics of pellets produced using sewage sludge combined with elephant grass and residual cooking oil. At first, sludge and grass were mixed in respective proportions of 25%-75% and 50%-50%. Afterwards, two more samples were created by adding 5% residual cooking oil to that mixtures. The parameters analysed were moisture, bulk density, elemental composition, immediate chemical analysis (ash, volatile and fixed carbon content), calorific value, fines content and mechanical durability. The material properties were compared to the European standards for pellets EN 14961-6. The results showed the pellets with a lower proportion of sludge presented higher calorific value and less ash content, but less bulk density and higher fines content. The oil provided an increase in calorific value, however, an increase in the sulphur content. Among the four samples, those with 25% sludge and 75% grass fitted all parameters according to the EN 14961-6 standards.

Keywords: pellets; sewage sludge; elephant grass; residual cooking oil; renewable energy.

DOI: 10.1504/IJETM.2022.120712

International Journal of Environmental Technology and Management, 2022 Vol.25 No.1/2, pp.122 - 133

Received: 23 Sep 2020
Accepted: 16 Feb 2021
Published online: 04 Feb 2022 *

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