How park and garden waste are dealt with today
Each year, approximately 450,000 tonnes of park and garden waste are generated in Sweden’s municipalities. Additionally, there is also a considerable amount of park and garden waste being produced by cemetery administrations and other private actors. Handling all the material in an effective way is challenging from a management standpoint, because it involves such large quantities and the material in question is heterogeneous. Some of it is composted, while the rest is incinerated. However, the latter often leads to issues with the incineration plant as the high levels of sand and nutrients in the park and garden waste cause significant wear on the equipment.
Why make biochar out of park and garden waste?
As of now, a significant proportion of the park and garden waste cannot be recycled as it contains too high levels of various contaminants, including heavy metals such as cadmium and lead. Several heavy metals, one of which is cadmium, are separated out when park and garden waste is converted into biochar using pyrolysis. Phosphorus and other nutrients can therefore be reintroduced without the heavy metals.