Energetic potential of algal biomass from high-rate algal ponds for the production of solid biofuels

Abstract

In this investigation, chemical characteristics, higher, lower and net heating value, bulk and energy density, and thermogravimetric analysis were applied to study the thermal characteristics of three algal biomasses. These biomasses, grown as by-products of wastewater treatment in high-rate algal ponds (HRAPs), were: (i) biomass produced in domestic effluent and collected directly from an HRAP (PO); (ii) biomass produced in domestic effluent in a mixed pond-panel system and collected from the panels (PA); and (iii) biomass originating from the treatment effluent from the meat processing industry and collected directly from an HRAP (IN). The biomass IN was the best alternative for thermal power generation. Subsequently, a mixture of the algal biomasses and Jatropha epicarp was used to produce briquettes containing 0%, 25%, 50%, 75%, and 100% of algal biomass, and their properties were evaluated. In general, the addition of algal biomass to briquettes decreased both the hygroscopicity and fixed carbon content and increased the bulk density, ash content, and energy density. A 50% proportion of biomass IN was found to be the best raw material for producing briquettes. Therefore, the production of briquettes consisting of algal biomass and Jatropha epicarp at a laboratory scale was shown to be technically feasible.

Properties of densified solid biofuels in relation to chemical composition, moisture content, and bulk density of the biomass

“…The general fuel quality and specifications for solid biofuels of raw and processed materials are also evaluated through ISO 17225-2 standard (Alakangas 2014). (Mani et al 2004;Erlich et al 2005;Kaliyan and Morey 2009;Kargbo et al 2010;Serrano et al 2011;Brosse et al 2012;Cardoso et al 2013;Ivanova et al 2014;Bhagwanrao and Singaravelu 2014;Lizotte et al 2015) The bulk density also governs the energy density in solid biofuels, as the bulk density and lower heating value determine the energy density of biomass (Costa et al 2017), and a high bulk density in any form of solid biofuel (i.e., pellet or briquettes) denotes a higher energy density. Table 3 summarizes bulk density, heating value, ash content, and mechanical durability of selected biomass types.…”

Microalgal–bacterial consortia for efficient wastewater treatment: Optimization using response surface methodology

“…However, the performance of the MBC is governed by culture time that affects the growth of algae (Qi et al, 2021; Valigore et al, 2012). Consequently, the effect on wastewater treatment, especially nutrient removal, needs to be optimized to meet the increasingly stringent wastewater treatment standards of MBC (Costa et al, 2017). Researches, at present, have shown that the wastewater treatment processed by MBC within hydraulic retention time (HRT) 2–7 days, increasing the time cost.…”