This paper describes the adaptation and development of a rotary in-vessel advanced composting system for sourceseparated garden and kitchen waste, food industry waste and other biodegradable municipal waste (BMW) as part of the UK Department for Environment, Food and Rural Affairs (Defra) New Technologies Demonstrator Programme. Over the life of the project, the plant aims to convert 10 000 t of BMW into high-grade fertiliser to be supplied to the agricultural market. Investigation and development work carried out in connection with an end market for the product is also summarised.