MBT - white knight or white elephant?

Is MBT the solution to meeting the Landfill Directive?
By Pat Wheeler and Dr Neil Varey, AEA Technology.

So called "non- incineration" treatment and disposal techniques such as Mechanical and Biological Treatment (MBT) and Biological and Mechanical Treatment (BMT) technologies are now being hailed as a solution offering the reduction in biodegradability needed to meet the Landfill Directive requirements.

With the targets posed by the Landfill Directive and the penalties that may be imposed through the Waste and Emissions Trading Bill likely to be in excess of £100/tonne, these technologies are seen as offering valid options within an integrated and sustainable waste management strategy. The jury, though, is still out as to whether they may conflict or be included within recycling targets, and if their products may only be considered as "stabilised waste" for landfilling or "fuel feed stocks" for cement kilns and power stations. They may therefore not provide the solution they claim to be able to.

On the limited success of recycling/composting in England and Wales only reaching 12% in 2000/01, Local Authorities in England are now facing the immediate challenge of the Best Value Performance Indicators for 2003/04 and 2005/06 and the longer term targets of 30% and 33% by 2010 and 2015 respectively as set down in Waste Strategy 2000. Interest in 'new' technologies has, consequently, never been higher as solutions are sought to help achieve these short and longer-term objectives.

However, prior to determinations by Local Authorities whether to include such technologies in their strategies, clarity is still needed as to exactly what is meant by "recycled"; "recovered" and by "disposal" so that Local Authority targets can be achieved through the incorporation of these technologies.

Currently, "recycled" means reprocessed in a production process for the original purpose, or for other purposes, with composting being separately accounted but included in the overall total. It excludes energy recovery and some wastes recycled such as soil and rubble and material anaerobically digested (although this is out to consultation).

'Disposal' is defined under the 1975 Waste Framework Directive (75/442/EEC), as operations included in Annex IIA that include, inter alia, "incineration on land (D10)", whilst "recovery” operations listed in Annex IIB include "use principally as a fuel or other means to generate energy (R1)". The European Court of Justice confirmed the latter in February 2003, giving some Local Authorities the confidence to look at alternative technologies to bridge the gap between recycling/composting, residual waste management and disposal.

However, all is still not clear in the UK and there are still unanswered questions. The issue of how the biodegradability will be measured and thus how far such treated and stabilised waste will contribute towards meeting the Landfill Directive requirements for diverting biodegradable wastes from landfill and the role of anaerobic digestion in contributing towards recycling/composting targets is still being considered at DEFRA. The matter being further complicated as the Waste and Emission Trading Bill defines biodegradable waste as 'any waste that is capable of undergoing anaerobic or aerobic decomposition, such as food and garden waste and paper and cardboard'.

It is now very important that DEFRA's new "Waste Implementation Programme", covering New Technologies, quickly provides the guidance and advice Local Authorities need to determine the potential role that MBT/BMT technology potentially offers. Advice is needed to cover risk, economics, environmental and health issues, operational aspects and the clarification of definitions with regards to its contribution to recycling targets and the biodegradability of its products for meeting the Landfill Directive requirements.

The costs for MBT/BMT in the UK are still based on European examples and are very much site dependant, involving permitting, emission limits and controls, aesthetic requirements, and local and regional issues for mainland Europe. Also, the models costed are based on pretreatment before landfill or incineration, rather than producing useable products. Reported capital costs are quoted at £100 per tonne (excluding gasification/pyrolysis) for a 60,000 tonne MBT/BMT compared with £350 for a 100,000 tonne incinerator in the UK. The Leicester MBT project, received £30 million over 25 year PFI award and the East London Waste Authority was awarded £47 million under PFI which included two BMT plants. Operating costs, again excluding any pyrolysis/gasification or collection costs, are quoted at between £40 -70 per tonne compared to £40-60 for incinerators in the UK.

As with all waste facility permitting in the UK, public perception and acceptability of these new technologies is very important. They may already be fated in that these technologies are likely to include some RDF combustion and, as a consequence, could be perceived by the public as incineration by any other name and suffer the same fate. This has already been experienced in Derby where initial optimism for SWERF, dealing with residual wastes, has been met more recently by local opposition concerning emissions and potential health problems and Shanks, in Milton Keynes, needed to submit a revised proposal which excluded the waste to energy facility. The alternative is to burn the waste in pre-existing facilities such as cement kilns or power stations. Cement kilns are limited in capacity and power stations require financial incentives that are provided from the renewable obligations to make burning waste viable.

However, waste does not count as renewable, even though a significant portion of the waste is renewable the plastics and other non-renewable combustible materials make it ineligible. Thus, expansion of this market requires some modification to allow the renewable portion of waste to be counted towards ROCs so that power stations will be willing to accept waste as a fuel.

To put this potential issue into perspective, the Environment Agency are anticipating that over 1,000 new waste management facilities will be needed to meet the requirements of the Landfill Directive. This will place a massive strain on both the waste industry, planning system and on environmental licensing processes, making Defra’s "Waste Implementation Programme" on new technologies all the more important.



Waste & resource management
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