The provision of waste management infrastructure is a major challenge. It must be legally compliant, environmentally and socially acceptable, technically and financially viable and resource efficient both at the time of commissioning and throughout its working life.
The totality of our waste management infrastructure must be sufficient and suitable to meet the needs of society now, and also to provide for a degree of flexibility going forward given the double impacts arising from changes in waste volumes and/or composition.
In committing to process waste in a particular way or to using a preferred treatment technology over a longer term, we must bear in mind the need for flexibility in the contractual arrangements to accommodate any variances and/or changes that might arise across the full term of the contract. The other alternative, depending upon circumstances (scale/tonnages/cost/term etc), is to consider a range of treatment technologies and/or methods over the period, in plant of a suitable scale, to provide a diversification of approach to changing circumstances.
One of the current key drivers of waste management policy is the EU landfill directive, which requires a reduction in the amount of biodegradable municipal waste (BMW) sent to landfill to 35% of 1995 levels by 2016 (2020 in the UK), and the pre-treatment of any remaining BMW that is disposed of in this way.
Defra’s New Technologies Demonstrator Programme (NTDP), described by Brooks and Powrie (2007), was established to encourage investment in pilot plants to showcase and potentially de-risk a range of new methods of treatment for BMW, some of which were operational in Europe but new to the UK. Technologies trialled included aerobic and anaerobic digestion, in-vessel composting, mechanical heat treatment (MHT), gasification and pyrolysis. At that time, these technologies were, so far as the UK was concerned, in their infancy in terms of both concept and application. In addition to the pilot plants themselves, and unusually for an exercise of this nature, an associated programme of research, monitoring and evaluation has generated data on their costs, effectiveness, strengths, weaknesses and general operational parameters. The associated research was a critical element as it provided evidence as to whether these technologies were commercially and operationally viable, their resource and energy efficiency and how they might be improved. In terms of commercial viability, we need to be mindful that at that time landfill tax was significantly lower than it is today.
The papers in this issue of Waste and Resource Management summarise the key outcomes of the NTDP. The paper by Powrie (2011) provides a summary and analysis of the NTDP as a whole. The performance of individual pilot plants are then described and discussed in more detail in the papers by Banks et al., 2011 (anaerobic digestion); Eades et al., 2011, Fletcher et al., 2011, Stentiford et al., 2011 (composting); Stringfellow et al., 2011 (MHT); Pugh et al., 2011 (gasification); and Williams and Barton, 2011 (pyrolysis).
The NTDP also supported, through the Technologies Research and Innovation Fund (Trif ), a programme of blue skies research projects investigating potential next-generation technologies for processing BMW. These included microwave pyrolysis, the use of membranes in anaerobic bioreactors to decouple solid and liquid retention times, biological hydrogen production, and autoclaving. The benefits of particle size reduction in aerobic and anaerobic digestion were also investigated. The key findings of the Trif projects are summarised in the paper by Powrie (2011).
The demonstrator projects met with varying degrees of success. For example, AD is now an established technology and some of the advanced thermal processes are now gaining traction.
Crucially, the associated research, monitoring and evaluation reported in this issue of Waste and Resource Management gathered high-quality data on each process, enabling the areas of strength, weakness and potential improvement to be identified clearly and with confidence. In this way, best practice can be shared with other potential project developers, ensuring a process of continuous improvement. Therefore, the information contained in this landmark volume will be of immense value to all those involved in the development, procurement and operation of waste management facilities that are and will remain legally compliant, environmentally and socially acceptable, financially viable, and resource and energy efficient.
