Assessment of the environmental impact of management options for waste wood
Defra has published an assessment of the environmental impacts of possible management options for waste wood across the lifecycle of the processes and end products; and the practicality of such options in the light of current arrangements and available processing facilities.
2. identify the range of waste wood management routes â including alternatives to current routes;
3. identify the more sustainable routes â using Life Cycle Assessment (LCA) and other analysis;
4. outline the practical and commercial issues associated with selected routes; and
5. assess various scenarios of waste wood management options for the future.
- Grade A and B waste wood is well managed through the current re-processing sector. This sector has good links with waste management companies, and with C&I and C&D waste wood producers. The major issues faced by the sector is the balance of demand and supply â i.e. that there is a great demand for waste wood for re-processing and not enough Grade A and B waste wood to meet this demand. This means that costs are increasing and the quality of waste wood being sent to re-processors is decreasing (which adds to re-processing costs). Better source segregation and greater incentives to segregate on small sites would improve the situation, but only if the logistics for storage and collection are solved for these small sites.
- The re-processing sector could probably also process Grade C waste wood for fuel if there were sufficient WID-compliant plants that could take this waste wood.
- There are considerable problems with obtaining reliable statistics on waste wood arisings, particularly from civic amenity waste and on understanding how some waste wood is managed (e.g. how much do small scale construction and demolition companies burn on site? How much waste wood goes to landfill? How much is exported?). Improved statistics would allow better planning for diversion of this waste stream from landfill, would enable developers to scope out better plans for energy recovery, and would enable relevant policies to be adopted for its management.
- There is a great potential to co-combust Grade C waste wood with SRF. However, in this work we have come across considerable confusion about the term SRF, including what it refers to and how it arises. In theory it should be possible to develop high biomass SRF for generation of power eligible for ROCs. However, the term âhigh biomass SRF‟ is used loosely without definition. Generally most experts expect SRF to contain closer to 50% biomass content (by energy). Better understanding of the potential of SRF, its biomass content, its co-combustion with waste wood and its production in the UK would allow a better understanding of its role in the recovery of energy from waste wood, particularly the more contaminated waste wood fractions. It is also important to understand when it is cost- and energy-effective to separate waste wood from mixed waste streams; and when energy recovery from an SRF produced from the mixed waste stream is more effective.
- Evidence indicates that large companies involved in construction and demolition can successfully segregate waste wood on site. However, small and medium size enterprises find this more difficult because of logistical constraints (man power, space on site etc.) and often find it easier to dispose of mixed waste. Investment in overcoming these issues could divert more good quality wood waste from landfill.
- Waste wood can be burnt on site at construction and demolition sites. More could be done to stop this practice and to achieve more efficient energy recovery from this wood waste in a boiler or large-scale power plant.
- The impact of the RHI on C&I waste wood arisings is not yet understood. However, it is likely that it may stimulate an increase in on site use of the wood waste for energy recovery, thus limiting the amount available to re-processors further.
- Zero waste to landfill policies are being adopted in a number of countries, but there is little information on how successful these policies are because they are too new for assessment. It would be interesting to follow such policies to see which stimulated most recycling and recovery of waste wood before England also adopts such a policy. In our analysis we assumed that there would be a ban on any biodegradable waste that was not stabilised and that this would include waste wood. However, waste wood is often very stable to degradation under the anaerobic conditions typical of landfill, particularly when it is heavily impregnated with preservatives.
- Data on WID energy recovery for waste wood is not good. WID compliance is not included in national statistics, which makes it difficult to know how many plants can take contaminated waste wood. This could be tackled by adding WID compliance as a recorded category in ReStats. This would provide a better indicator of how much capacity there is to take Grade C waste wood, and might provide an option for re-processors to send rejected loads to.
- Important issues affecting the success of management routes examined in this report include segregation/separation of waste, lack of energy recovery plants for waste wood that comes under WID, planning permission, capital costs and transport.
There is a large amount of uncertainty around the end use for hazardous waste arising from demolition. Railway sleepers and telegraph poles are generally well handled, but there is no data on hazardous waste wood from other sites and no record of where this waste wood ends up. Poor management of such waste wood may cause environmental and human health issues.
- A zero waste to landfill policy would have a large impact on the separation and reprocessing industry, increasing the potential for re-processing particularly Grade C waste wood and perhaps for improved separation of Grades B and C. However, the Grade C waste wood must have somewhere to go and policies to incentivise WID energy recovery plants would provide an answer.
- Other than a zero waste to landfill policy, a balance of both energy incentives, and waste disincentives would achieve the most desirable outcome in terms of both reduction of waste wood to landfill, and increased energy recovery. These policies would need to be accompanied by investment in infrastructure and logistics to ensure their success.
- The panelboard sector is only protected by waste policies â energy policies and market forces both have a negative impact on the amount of waste wood available for the panelboard sector.