Biochar and gypsum amendment of agro- industrial waste for enhanced black soldier fly larval biomass and quality frass fertilizer
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Date
2020
Authors
Beesigamukama, Dennis
Mochoge, Benson
Korir, Nicholas K.
Komi, K
Fiaboe, M.
Nakimbugwe, Dorothy
Khamis, Fathiya M.
Dubois, Thomas
Subramanian, Sevgan
Wangu, Musyoka M.
Journal Title
Journal ISSN
Volume Title
Publisher
PloseOne
Abstract
Black soldier fly (BSF) (Hermetia illucens L.) is one of the most efficient bio-waste recyclers.
Although, waste substrate amendments with biochar or gypsum during composting process
are known to enhance nutrient retention, their impact on agro-industrial waste have not
been documented. Hence, this study focuses on a comparative effect of agro-industrial
waste amended with biochar and gypsum on BSF larval performance, waste degradation,
and nitrogen (N) and potassium retention in frass fertilizer. Brewery spent grain was
amended with biochar or gypsum at 0, 5, 10, 15 and 20% to determine the most effective
rates of inclusion. Amending feedstock with 20% biochar significantly increased wet (89%)
and dried (86%) larval yields than the control (unamended feedstock). However, amendment with 15% gypsum caused decrease in wet (34%) and dried (30%) larval yields but conserved the highest amount of N in frass. Furthermore, the inclusion of 20% biochar recorded
the highest frass fertilizer yield and gave a 21% increase in N retention in frass fertilizer,
while biomass conversion rate was increased by 195% compared to the control. Feedstock
amendment with 5% biochar had the highest waste degradation efficiency. Potassium content in frass fertilizer was also significantly enhanced with biochar amendment. At maturity,
frass compost with more than 10% inclusion rate of biochar had the highest cabbage seed
germination indices (>100%). The findings of this study revealed that initial composting of
biochar amended feedstocks using BSF larvae can significantly shorten compost maturity
time to 5 weeks with enhanced nutrient recycling compared to the conventional composting
methods.
Description
A research article published in PloseOne
Keywords
Biochar, agroindustrial waste, frass fertilizer
Citation
Beesigamukama D, Mochoge B, Korir NK, Fiaboe KKM, Nakimbugwe D, Khamis FM, et al. (2020) Biochar and gypsum amendment of agroindustrial waste for enhanced black soldier fly larval biomass and quality frass fertilizer. PLoS ONE 15 (8): e0238154. https://doi.org/10.1371/journal. pone.0238154