Pre-treatment of fruit and vegetable waste prior to BSFL composting does not improve efficiency but simplified processing

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In our latest publication on black soldier fly larvae (BSFL; Hermetia illucens) composting, we investigated the impact of pre-treatment on process efficiency and greenhouse gas emissions. We evaluated BSFL composting of broccoli and cauliflower cuttings and orange peel with and without pre-treatment, and compared the results to those for food waste (control). The two pre-treatments we investigated were a 2 w inoculation with 1) the fungi Trichoderma reesei or 2) ammonia solution. The hypothesis was that the fungi would break down cellulose and hemicellulose to easily available carbohydrates, while the idea with the ammonia pre-treatment was that it would both break cellular structure and add nitrogen for the microbial community to assimilate into proteins.

Studyvisit to VAFAB in VÀsterÄs

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We went on a study trip to the waste management company VAFAB in VĂ€sterĂ„s with students from our two courses about waste management, ”Safe nutrient recycling 15HP” and ”Waste management 5HP”. A very interesting tour that gave insights about the volumes of waste that we all generate, among the things we visited we had a bus tour over the 45 hectar old landfill. Additionally we had a nice tour of the newly re-built biogas plant and hear about the challenges they had with sediments in the reactors from egg shells, sand and dirt that consumes reactor volumes. The produced biogas is used for the local buses and the bio-fertiliser is collected by local farmers for free.

Food waste bags that have been collected in the VÀsterÄs region are stored before they are feed to the anaerobic digester.

MVM 10 year jublee

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Last week our main building MVM, which contains our offices and laboratories, turned 10 and we all celebrated together! Many bright brains have entered and left this building in the past 10 years, so to catch up with the current staff, some of us took the celebration as an opportunity to present their group to our fellow colleagues. Nothing better than a stroll through our diverse work place, with Fika and coffee afterwards!

Speaking of Fika: The fly larva had their own version of Swedish Fika, two boxes containing 10.000 larva each were fed (vegetarian) hamburgers and cake and our colleagues could vote on menti.com which of the two meals would be gone first! It was a tight race but in the end the larva clearly preferred the cake! Who can say no to some easily available carbs in winter!

Studyvisit from Kjell och MĂ€rta Beijers Stiftelse

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Cecilia Lalander from Kretsloppsteknik welcomed visitors from the Kjell and MĂ€rta Beijers Stiftelse at SLU campus in Ultuna. In the spotlight was the latest project “5 ton fish on the counter” (see blogpost from 04. March https://blogg.slu.se/kretsloppsteknik/2021/03/04/red-containers-at-campus/), where feed for trout was produced from insect meal at Campus Ultuna.

The visit was a great opportunity to show the groupÂŽs strong competences and relevance in regards of circular economy (wastemanagement and feed production). After a quick visit, the group hurried on to visit other research groups and get an insight to the wide and important research conducted at SLU.

The Kjell and MĂ€rta Beijer Foundation was founded in 1974 through a donation from Kjell and MĂ€rta Beijer. In addition to scientific research and education, the foundation supports culture, above all in connection with Swedish design and home furnishing tradition. Among other things, the foundation is behind the Beijer Institute, one of the world’s leading research centers in ecological economics. It had been a great day and Cecilia received a lot of interesting questions and also witnessed some of the visitors testing our dried larvae first hand!

Our BSF project “5 ton grön fisk i disk” featured in Dagens nyheter

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From February to May 2021, the project “5 ton grön fisk i disk” (partly financed by Vinnova) produced 1,7 tons of larvae on a mix of 10 tonnes vegetable and bread waste. The vegetables were discarded vegetable cuttings from

Sorunda Grönsakshallen and the bread was out-of-date Fazer bread from local supermarkets. The larv ae were not only produced at SLU campus but they were also further processed here: after drying at 60°C for 48 h, the dry larva were pressed in a screw press to separate the protein from the fat. The defatted protein meal was then turned into fish feed, containing many other locally sourced ingredients, for rainbow trout. The trout were grown by Älvdalslax in Dalarna.

The residue from the treatment, the frass, was used as soil amendment on the nearby student run permaculture garden. Dagens nyheter found out about this cool project and came to visit us. Jessica Ritzen followed Cecilia Lalander and Anders Kiessling through the different stages of the protein production for the 5 ton fish on the counter project. Read the full article here.

New Formas project in the call From research to implementation for a sustainable society 2021

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Cecilia Lalander from the Department of Energy and Technology and Anders Kiessling from the Department of Animal Nutrition and Management are part of a project with partners from all over Sweden who have just been granted SEK 3.8 million from FORMAS for a pilot project in which artificial intelligence (AI) will support the development of a sustainable urban food production system.

Northern Sweden has recently attracted large industries and server halls as well as the next generation fossil-free steel industry (H2GreenSteel), due to its easy access to renewable energy and natural resources, as well as a cool climate. Boden municipality aims to be Europe’s most resource-efficient and carbon-neutral municipality by 2025. In fact, since 2020, Boden has initiated a large-scale symbiosis project called the Boden Energy Symbiosis, part of the Boden Business Park. In fact, since 2020 Boden has initiated a large-scale symbiosis project called the Boden Symbiosis Cluster, part of the Boden Business Park. One of the initiatives aim at creating an urban food competence platform of commercial size to be used as a national asset for implementing and testing innovative solutions for food production systems.

Our latest publication on black soldier fly larvae composting

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Check out our latest publication in Waste Management Process efficiency in relation to enzyme pre-treatment duration in black soldier fly larvae composting. We investigated the impact of enzyme pre-treatment time duration on the efficiency, in terms of biomass conversion efficiency and material reduction, in black soldier fly larvae (BSFL) composting of lettuce and cabbage (vegetable cuttings from Grönsakshallen Sorunda). We found that direct addition of enzyme (i.e. no pre-treatment time, but adding the enzymes as the same time as the larvae) was the only treatment that significantly improved process efficiency.

New publication on Co-composting of banana peel and orange peel waste with fish waste to improve conversion by black soldier fly (Hermetia illucens (L.), Diptera: Stratiomyidae) larvae

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This study aimed to enhance the biodegradable solid waste management of low-quality food and agro-industrial waste streams, in terms of BSFL process performance efficiencies by means of co-composting. A fibre-rich, hard to degrade waste stream such as fruit peels by BSFL, was co-composted with a low-quality protein-rich waste stream (fish waste). Results show that co-composting has the ability to increase the BSFL composting efficiencies from nutrient-imbalanced substrates such those used in this study. Protein content increased as more fish waste was added into the substrate mixtures. Biomass conversion rate was generally increased by the addition of fish waste in the substrate mixtures and the highest conversion and BSFL weight achieved was 25 % and 269 mg larva-1, respectively, with 75 % fish waste (12 % protein addition) inclusion. However, BSFL treatment efficiency parameters showed wide variation with inclusion of 75 % fish waste in the substrate, possibly owing to differences in nutritional composition (especially fat content) of different fish waste batches. Lower variations in process efficiency renders higher reliability of the treatment process. Therefore, 25 % inclusion of fish waste (4 % protein addition) was concluded to be beneficial and sufficient enough to improve the overall BSFL process efficiency.

To read more, press here.

Isibika A., VinnerĂ„s B., Kibazohi O., ZurbrĂŒgg C. & Lalander C. (2021) Co-composting of banana peel and orange peel waste with fish waste to improve conversion by black soldier fly (Hermetia illucens (L.), Diptera: Stratiomyidae) larvae. Journal of Cleaner Production 318, 128570

Interested in practical aspects of Black Soldier Fly (BSF) waste processing?

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As BSF has become mainstream as an exciting way to treat organic waste, we receive more and more inquiries with questions on “what shall I” and “how shall I”. Academic journal articles seldom give enough easily digestible answers for practitioners, interested in starting or already operating a BSF facility.

For this purpose a practical knowledge hub webpage has been established which contains information all around BSF waste processing in a hopefully easy and practical format for people “in the field”.