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Research article - Peer-reviewed, 2020

Process efficiency and ventilation requirement in black soldier fly larvae composting of substrates with high water content

Lalander, Cecilia; Ermolaev, Evgheni; Wiklicky, Viktoria; Vinneras, Bjorn

Abstract

In order to transition from a linear to a circular economy in the organic waste management sector, more of the elements in waste need to be recycled. Use of black soldier fly (Hermetia illucens L.; Diptera: Stratiomyidae) larvae (BSFL) for organic waste treatment has potential to harvest more complex molecules than conventional methods. Many organic waste substrates have high water content (>80%), but the impact on BSFL treatment efficiency of substrate water contents >80% is not known. This study evaluated the impact of high water content food waste on BSFL composting efficiency in terms of waste-to-biomass conversion ratio, material reduction, larval survival and the ventilation required for enabling dry separation of larvae from residue. In total, six water contents ranging from 76% to 97.5% were evaluated in two experimental trials. It was found that increasing water content reduced biomass conversion ratio and survival rate of the larvae, from 33.4% of volatile solids (VS) and 97.2% survival in 76% water to 17.5% of VS and 19.3% survival in 97.5% water. Furthermore, we found that the ventilation requirement for achieving dry separation of larvae from residue could be modelled by estimating the amount of water that would need to be removed, taking into account the water bound in the larvae, and knowing the specifics of the ventilation set-up of the modelled system. The findings could have implications on the waste management sector interested in implementing BSFL treatment, as the findings demonstrate that it is possible to treat wet substrates (such as fruit and vegetable wastes) without any pre-treatment other than grinding and attain an adequately dry residue for enabling dry separation of the larvae from the residue. (C) 2020 The Authors. Published by Elsevier B.V.

Keywords

Animal feed; Biodegradable waste; Circular economy; Eco-technologies; Hermetia illucens; Nutrient recycling

Published in

Science of the Total Environment
2020, volume: 729, article number: 138968
Publisher: ELSEVIER

Authors' information

Swedish University of Agricultural Sciences, Department of Energy and Technology
Swedish University of Agricultural Sciences, Department of Energy and Technology
Swedish University of Agricultural Sciences, Department of Energy and Technology
Swedish University of Agricultural Sciences, Department of Energy and Technology

Associated SLU-program

Food Waste

Sustainable Development Goals

SDG12 Ensure sustainable consumption and production patterns

UKÄ Subject classification

Environmental Sciences

Publication Identifiers

DOI: https://doi.org/10.1016/j.scitotenv.2020.138968

URI (permanent link to this page)

https://res.slu.se/id/publ/108296