Concentrate or dilute contaminants? Strategies for Swedish wood waste

This thesis aims to assess the environmental consequences of management strategies for wood waste in Sweden. There is a special focus on separation strategies and in what way they influence environmental aspects related to the presence of heavy metals in the waste. Actors’ incentives and capacity to influence wood waste management are analysed, emphasising the importance of driving forces such as governmental regulation and market interactions. The results show that, in comparison to present dilution practice, separation of contaminants would lead to decreased heavy metal emissions during treatment of wood waste while still recovering a similar energy yield from the waste. Such measures would also increase possibilities for resource-saving reuse of generated ash. For most heavy metals, however, long-term pollution concerns related to accumulations in landfills and unintentional co-recycling seem difficult to address, regardless of separation strategy. An exception is wood waste that according to regulation is to be separately handled as hazardous, i. e. industrial preservative–treated wood, for which separation measures also would address such future concerns. It can be concluded that regulation influences the environmental consequences of separation measures. This indicates that governments could play an important role in environmental policy by, for instance, stimulating separate handling of certain discarded products such as industrial preservative–treated wood. How far to push for separation is however a matter of policy rather than science, especially regarding pollution concerns related to long-term uncertainties. Other factors influencing the environmental consequences of separation measures in wood waste management are a well-developed district heating system and availability of sophisticated incinerators for energy recovery of contaminated materials. Actors in the energy sector involved in fuel and heat production have quite restricted capacities for separation of contaminants. Instead, achieving substantially less contaminated wood waste seems to require actors in the waste and construction sectors to develop source separation measures. The fact that such measures involve actors lacking professional standards for waste management, who therefore must be educated and trained, constitutes a fundamental obstacle to efficient separation. Perhaps even more hampering is that source separation at present leads to increased waste disposal costs for actors in the construction sector. Such economic outcomes of source separation are unfavourable, since these actors primarily consider discarded wood material as a disposal problem for which the costs should be minimised. Despite these obstacles, however, this thesis contains empirical evidence showing that some actors have proved capable of achieving relatively efficient separation. At present, only a minor share of industrial preservative–treated wood waste is separately handled as hazardous in Sweden. For most actors in the energy, waste and construction sectors, the incentives for such measures appear low even though introduced regulations potentially could have created such incentives. It appears as if a lack of steering mechanisms such as communication and supervision have neutralised the inherent pressure from regulation in many cases. Quality requirements, on the other hand, can be concluded to be of outmost importance for motivating separation measures. Unfortunately, present market forces encourage actors in the energy sector to practice inconsistent enforcement of stated quality requirements. As a consequence, actors in the waste and construction sectors do not experience any strong pressure for separation of contaminants from their customers. In fact, such an inconsistent enforcement of quality requirements seems to have counteracted legal pressures for separation, due to present customer-oriented business management.