Category: English

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.

We went on a study trip to the waste management company VAFAB in Västerås 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 Västerås region are stored before they are feed to the anaerobic digester.

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!

Cecilia Lalander from Kretsloppsteknik welcomed visitors from the Kjell and Märta 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 group´s 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 Märta Beijer Foundation was founded in 1974 through a donation from Kjell and Märta 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!

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.