Residual waste treatment options vary in the extent to which they recover value from the waste stream. The two main sources of value are materials which can be reprocessed and energy recovery through a thermal and/or biological treatment process.
Recovery of materials reduces the amount that goes to landfill and therefore it should be recognised that one of the benefits of material recovery will have already been considered under Diversion from Landfill (See above). WS2007 set national targets for the reuse, recycling and composting of household waste - of at least 40% by 2010, 45% by 2015 and 50% by 2020. Each Authority should play its part in achieving these targets. Many will have set their own targets in their own MWMS for re-use, recycling and composting, and all Local Authority Agreements (LAAs) will measure the local performance on these options for waste management. Therefore it is legitimate to evaluate the extent to which options deliver additional recycling. As with diversion this can be quantified through a waste flow modelling exercise. However, there must be a market for the recovered material. Authorities should take account of the current and likely market conditions when evaluating the extent of material recovery. Without an outlet the material is likely to end up being used for thermal treatment or landfilled.
Energy recovery should be assessed by reference to the overall efficiency of the system in terms of converting inputs (principally waste) into energy outputs (i.e. heat and power). This is not an integral part of the waste flow modelling and the Authority should ensure it has the necessary skills or advice available to undertake this assessment on a like-for-like basis.
The Authority should seek to maximise energy recovery (overall efficiency) by exploring the potential for combined heat and power applications at the proposed site(s). This issue will only affect the options appraisal to the extent that the choice of technologies affects the likelihood of there being an appropriate heat off-taker. In general, site issues are likely to be more significant but the technology impact on CHP potential should also be considered.