In Flanders, garden fruit and vegetable (GFV) waste is selectively collected and composted in 7 composting plants, in six of which aerobic indoor composting is used. In the seventh plant waste is anaerobically digested first followed by an aerobic post-treatment. The total amount of waste composted was about 275 000 tons in 1997 (OVAM, 1999). The nominal capacity of the composting plants varies from to 20 000 to 60 000 tons a year. In the same year official complaints about odour nuisance caused by the composting activities were registered by local environmental authorities for 6 of the seven composting plants. Important factors in this respect are: the relative large sizes of the plants, the limited spatial separation between composting plants and residential areas and the fact that some composting plants were in their start off period.
Different actions were undertaken by the authorities and in two cases plants shut down temporarily or had to reduce their capacity drastically during summer period. As a result the sector became sensitive to the problem and initiatives were taken in order to initiate measuring programmes and to implement codes of good practice. One action was to set up a monitoring campaign in order to evaluate the impact of the odorous emissions of the different composting plants on the neighbourhood. A second action was to evaluate current waste gas treatment systems installed in the composting plants.
In this paper a general overview of the results of both projects is given.