This edition is a collection in two volumes of the presentations at the 8th international conference of an FAO network on recycling agricultural, municipal and industrial waste that was held in Rennes, France, from 26th to 29th May 1998. The theme of the conference was management strategies for organic waste used in agriculture and it was organised in five parts: management strategies for organic waste used in agriculture, agronomic value of organic waste, measuring, modelling and management of gas emissions, waste treatment and management, environmental impacts.