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Forced air flow and distribution in landfilled wastes - WR0302

This research project will investigate air injection in landfills. It will improve the theoretical knowledge and practical understanding of the effects of air injection in municipal wastes. Creating aerobic conditions in landfilled waste has the potential to stabilise closed and operational landfills offering considerable long-term environmental benefits. Where research has been carried out, methane emissions have been virtually eliminated to significantly reduce the global warming potential of uncontrolled methane release from landfill. In addition, aeration has markedly reduced the pollution risks to ground and surface waters from leachate generated from sites.

Yet, there is very little understanding of the mechanisms and controls that affect aeration in landfills. There are no current guidelines for implementing an air inject scheme, or indeed any design standards. Greater knowledge of the distribution of air through a landfill and the effectiveness of air injection systems are crucial factors for successful design and engineering.

The central aim of this research project is to improve our understanding of air injection in municipal waste, by developing the scientific and technical knowledge of the flow of air in waste materials. The project has been designed to combine the research and engineering skills of both academic and commercial organizations. The project is being led by the University of Southampton and supported in the field by Purcell Limited.

The work involves a number of stages and will commence with a review of the current understanding of aeration in landfills, with reference to both theoretical work and laboratory/ field scale applications. This review will identify the key components that will affect air flow through drained waste materials. The findings from this review will be used to: (1) inform the detailed design of experimental research in a newly constructed field scale research facility (Purcell Ltd’s Aerox facility); and (2) develop and incorporate air flow modelling capabilities into the University of Southampton’s `Landfill Degradation and Transport` (LDAT) model.

The next stage will involve a six month experimental phase to generate key process data. The aeration model (LDAT) will be used to analyse the data and gain a better understanding of air injection in municipal waste. The research outputs will be set out in a final contract report and the landfill aeration model will be released.

The knowledge gained from this research will be transferable to applications at full-scale sites. Ultimately, this research aims to provide key data for policy makers, regulators and operators for designing and engineering aeration schemes for landfills. With effective design and management, aeration schemes could deliver significant long-term environmental and societal benefits.

The project addresses Programme Area 3.2 (`Managing residual waste in landfill`) of Theme 3 (“Residual Wastes Management”) of the Defra Waste and Resources R&D Strategy and addresses the potential sustainability of landfills and ways in which the burden of long term management problems of landfills can be shortened for future generations. Because the research is, in part, fundamental in nature the work will also be relevant to assessing the potential for aerating and reducing the pollution load of post Landfill Directive treated wastes placed in landfills.
The overall aim of the proposed research is to contribute to the development of the scientific and technical understanding of the flow of air in waste materials using field data and numerical modelling.

The specific objectives of the research are as follows:

1. Review the theory of air/ gas flow in drained waste materials to identify a theoretical framework that takes into account waste heterogeneity and composition and appraise empirical data from published work on aerobic treatment of waste in field and full-scale conditions (within 3 months).

2. Incorporate the theoretical framework into the established University of Southampton model for landfill degradation and transport (LDAT) (within 6 months)

3. Manage a series of coordinated short-term field trials to generate key data on efficient air distribution related to operational conditions on homogenised municipal waste (over a 6 month period)

4. Use the LDAT model to analyse experimental data generated from the trial to gain a better understanding of controlled air distribution through municipal waste (9-12 months from project start)

Project Documents
• Final Report : Forced air flow and distribution in landfilled wastes (WR0302)   (2802k)
• Final Report - Annex : WR0302 - Annex A   (119k)
• Final Report - Annex : WR0302 - Annex B   (126k)
• Final Report - Annex : WR0302 - Annex C   (257k)
• Final Report - Annex : WR0302 - Annex D   (165k)
• Final Report - Annex : WR0302 - Annex E   (156k)
• Final Report - Annex : WR0302 - Annex F   (2429k)
• Final Report - Annex : WR0302 - Annex G   (727k)
• Final Report - Annex : WR0302 - Appendix 1   (1844k)
• Final Report - Annex : WR0302 - Appendix 2   (96k)
• Final Report - Annex : WR0302 - Appendix 3   (401k)
• Final Report - Annex : WR0302 - Appendix 4   (423k)
• Final Report - Annex : WR0302 - Appendix 5   (884k)
• Final Report - Annex : WR0302 - Appendix 6   (1153k)
Time-Scale and Cost
From: 2006

To: 2008

Cost: £129,800
Contractor / Funded Organisations
University - Southampton
Environmental Protection              
Landfill Management              
Managing residual waste in landfill              
Pollution Prevention and Control              
Residual Wastes Management              
Techniques & methodolgies for waste management              
Waste Management              
Fields of Study
Waste Management