From waste to worm

PhD defence

From waste to worm

PhD candidate mr. B (Bob) Laarhoven
Promotor CJN (Cees) Buisman
Co-promotor BG (Hardy) Temmink
dr. HJH (Hellen) Elissen
Organisation Wageningen University, Sub-department of Environmental Technology

Fri 15 December 2017 11:00 to 12:30

Venue Auditorium, building number 362
Generaal Foulkesweg 1
6703 BG Wageningen

Valorisation of waste streams from by-products to worm biomass

Aquatic worms possess a great potential to be used as a sustainable fish feed once mass production is feasible using clean (no pathogens, low levels of heavy metals) and low value waste streams from e.g. food industries. A large range of waste streams can potentially be used for the production of in particular blackworms (Lumbriculus variegatus). A new reactor design was tested with the use of sludge from the potato starch processing industry. In this design a gravel layer mimics the worm’s natural habitat and simultaneously acts as a separation layer between the worm-feed compartment and the water column. The design showed improved separation of worms, sludge and compact worm faeces, while securing a high worm production rate at a stable density. The worm’s macronutrient composition also makes it a promising aquaculture feed source. A very stable fatty acid composition rich in unsaturated fatty acids and high protein levels makes worms suitable as fish feed for especially freshwater fish. The commercial success will largely depend on the acceptance of blackworms as a safe feed for cultured animals and the legalization of food waste products for worm feed applications.