Fly larvae composting

Last changed: 14 April 2021

The overall objective in this project is to increase the value of the organic waste, to enable closing the plant nutrient loop between the city and the agricultural production and to reduce the import of food, feed and chemical fertiliser.

In a circular economy system, the nutrient flow needs to be circular, meaning that the nutrients extracted from the soil into our food, should be cycled back into the soil again. The monetary flow, is however, not cyclic in a circular economy system. We pay for the food we eat, while the farmers pay for fertilisers.

The generated food waste has to be treated, and this treatment also have a value. In a linear flow system, the least expensive option is often used for waste management, in most cases this mean landfilling or dumping (globally 60 % of all the waste is landfilled). In the long-term, however, the disposal of organic matter at landfills lead air and water pollution.

Due to the short-time cost of adequate treatment of organic waste, valuable products, in addition to the gate fee for waste disposal, should be generated in the treatment to cover the treatment cost in a circular economic system. In the long-term, the treatment will be less expensive than disposal, as it will not pollute the environment and valuable plant nutrients will be used in a more efficient way.  

The fly larvae composting technology, which is new and still not established in Sweden, is a large step towards the transition to a circular economy system. In such a system, the biomass that is viewed as a waste in today’s food chain can be converted into valuable resources using a process found in nature. In the fly larvae composting the fly larvae are grown in food waste and the grown larvae separated from the treatment residue.

The separated larvae have a high content of protein and fat and can be used as ingredient in animal feed and replace fish and soy meal as well as fish oil. This technology has double benefits: the waste is treated in a technology with low environmental impact, while at the same time reducing the current environmental stress of producing animal protein and oil.

Fly larvae composting for organic waste management is new technology in Sweden with great potential. The aim of this project is to use the knowledge on fly larvae composting, accumulated at the Environmental Engineering group at SLU in the past seven years, and apply it in full scale. The technology will be further developed and then be presented to stakeholders in the organic waste management for further exploitation. The solutions developed at SLU will be brand protected, with the aim to further develop the treatment technology in Sweden as well as abroad while guaranteeing the quality and safety of the treatment process and generated products.

Photo: Anna Simonsson


Five different scalable standardised modules will be developed within the project, for: fly rearing; BSF composting; separation of larvae and residue, and separate modules for refinement of larvae and residue, respectively.

The main project partner is Eskilstuna Strängnäs Energi och Milljö (ESEM).

The project is financed by Vinnova.

Start time: 2018-03-01