Blog from the Environmental Engineering Research Group at SLU
Evgheni Ermolaev from Environmental Engineering group answers a reader’s question in an article in Forskning & Framsteg.
Read the whole article (in Swedish, use google translate) at Forskning & Framsteg
Contact: Evgheni Ermolaev
Our latest publication on BSFL composting entitled Process efficiency and ventilation requirement in black soldier fly larvae composting of substrates with high water content has been recently published in Science of the Total Environment. In this study we investigated the impact on increasing substrate water content on the process efficiency in black soldier fly larvae composting. We used the gathered data to make a model predicting the required ventilation for achieving a residue dry enough to allow for dry separation of larvae from treatment residue at the end of the composting. In contrast to what other studies have found, we fund that it is possible to BSFL compost substrates with water content 80 – 90 % and dry separate the larvae from the residue. For substrates with water content >90% it was more difficult, as the process efficiency decreased greatly, while the ventilation requirement increased.
ProCivitas private school for grade 10-12 is a small school with students in the science program and the social science program. The school provide the students with lectures about research once every month, called the lecture of the month, with different themes. This month, the theme was sustainable systems and Lovisa Lindberg from the group went there to talk about fly larvae composting but also Maria Westerholm from a different department at SLU went there to talk about biogas research.
The aim of the project is to evaluate how simple the system can be and how fast the process goes. The students are driving this experiment with aim to produce feed protein that can be used for chicken or fish production. The substrate is the canteen leftovers that would otherwise become food waste. The project at the school is a part of an EU collaboration project ”Envising” with focus on sustainability.
Follow the link to check out the larvae:
A paper was published in the Journal of Cleaner Production as a result of the partnership established between the Environmental Engineering Research Group at SLU and the PhD candidate IvĂŁ Guidini Lopes, a researcher from SĂŁo Paulo, Brazil. This paper addresses the management of waste generated in aquaculture enterprises (fish carcasses) by larvae of the black soldier fly (BSF, Hermetia illucens).
Earlier this week, a few members of Kretsloppsteknik hosted a group of SIDA’s International Training Programme participants in Uppsala. NIRAS on behalf of SIDA implements a number of International Training Programmes. Kretsloppsteknik is involved as part of this program through NIRAS with focus on participants from both Asian and African countries. During these visits, we teach, present, and do technology demonstration through field visits talking about safe nutrient recycling, source-separating sanitation systems, management of organic wastes, socio-technical systems analysis, etc.
In this seminar, moderated by Alejandro Jiménez of the Stockholm International Water Institute, different aspects of employment in the sanitation sector are discussed. Rémi Kaupp from WaterAid tells us about the findings presented in a new WHO report on the Health, Safety and Dignity of Sanitation Workers. Martin Mawajje from the University of KwaZulu-Natal (South Africa) describe how the emptying services in informal settlements can be formalised using a case from Kampala, Uganda as example. Daniel Ddiba, from the Stockholm Environment Institute tells us about a tool they have developed called REWAMP that can estimate and compare the circular economy potential of sanitation derived products from different sanitation technologies. The last presenter is Cecilia Lalander from our group that gives an example on how black soldier fly larvae treatment can be implemented by a sanitation entrepreneur.
Thursday last week (31/10), Björn and Cecilia from the Environmental Engineering group visited Västerås and presented about waste management using insects in the seminar held in Honour of Professor Erik Dahlquist. Erik Dahlquist is Professor in Energy Technology at the Mälardalen University and has with the help of his long experience in improvements of process efficiency development co-developed the ventilation system used in the fly larvae treatment system. We got to listen to other very interesting presentations on the batteries needed for our fossil free future and we got to listen to the tale of the development of the collaborative robot YuMi at ABB. Erik finished the seminar presenting the development of energy production and usage in primely Sweden from the 1950s till today and gave a prognoses of what can be expected up till 2090. Very interesting! Erik is to be retired but will work part time as Senior Professor from the start of next year. We hope for continued great collaboration and wish Erik good luck in future and more time with family and his triathlon endeavours.
How does the fat content and composition in the larvae of the black solider fly (Hermetia illucens) change with the diet provided to them? In our latest article published in Waste Management, Nils Ewald and co-authors brings new knowledge on this topic. The study is based on eleven feeding trials were the larvae were fed diets based on mussels, fish, bread and food waste. The larval fat was found to contain mainly saturated fatty acids, especially lauric acid, but was also affected by the weight of the larvae and the diet. For example, the larvae fed with mussels and fish contained EPA and DHA – Omega- 3 fatty acids that are valuable for aquaculture. However, the levels of these fatty acids were found to be too low to replace fish oil in fish feed but could potentially be used for replacing the vegetable oil fraction. Other possible applications of the larval fat could be in the production of food or fuel.
Alice Isibika and co-authors have published a new study in the journal Waste Management, on the application of pre-treatments prior BSFL treatment of banana peels as a fibrous and nutrient imbalanced substrate to enhance bioconversion ratio. The applied pre-treatments were non-protein nitrogen for balancing the carbon/nitrogen , heat and microbes(fungi and bacteria) pre-treatments for breaking down complex compounds into more readily available forms in the banana peels to be consumed by the BSFL. They found that direct addition of ammonia solution in the banana peel and addition of both fungi (Trichoderma, Rhizopus) and bacteria (BSFL gut bacteria) improved the BSFL response efficiencies while heat treatment did not improve. For microbial pre-treatment 14 days was found to be the total time to achieve sufficient degradation of the banana peels for BSFL consumption.
