Epsilon Archive for Student Projects

Abstract

Municipal solid waste- and especially organic solid waste management has be- come a major challenge in both developing and developed countries and is often related to the spread of diseases. At the same time, an increase in the demand for animal feed protein causes disturbances in (marine) ecosystems and nutrient recy- cling in soils is unsatisfactory in many places. These issues have a major negative impact on the environment. Black soldier fly composting could solve these prob- lems; by using the larvae of the black soldier fly (Hermetia illucens) to process organic waste and produce two valuable products: black soldier fly larvae, which could be used as chicken and fish feed, and the residue that can function as an or- ganic fertiliser.
The aim of this study was to identify specific process parameters leading to op- timised performance of a continuous black soldier fly composting system. This was accomplished by measuring specific parameters (pH, compost maturity, total solids, organic content) on various points along two plug flow reactors operated with dif- ferent larval feeding regimes (40 mg dry food/larva/day and 60 mg dry food/larva/day) and identifying differences between the two regimes.
The pH, compost maturity, total solids, organic content, prepupal weight, mate- rial reduction and biomass conversion rate did not differ significantly (P<0.05) between the two feeding regimes. However, survival rate of the larvae was significantly higher (100%) when fed with 60 mg total solids food/larva/day in comparison to when following the feeding regime with 40 mg total solids food/larva/day (70%). A material reduction of 68% (85% on wet basis) and a waste- to-biomass conversion rate of 19% on a total solids basis was achieved in the system.
It was found that black soldier fly composting can process more waste than what was expected per larva and day. However, further studies are needed in order to increase the total amount of waste treated in the unit.