2003 International Ash Utilization Symposium, Center for Applied Energy Research, University of Kentucky, Paper #20. Copyright is held by the Authors.

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The Environmental Impacts of Using Fly Ash – the UK Producers’ Perspective

Lindon K. A. Sear¹, BSc (Hons), PhD, FICT, Andrew J. Weatherley², BSc (Hons), MICE CEng and Andrew Dawson, MA, MSc³

¹ United Kingdom Quality Ash Association, Regent House, Bath Avenue, Wolverhampton, West Midlands, WV1 4EG, UK

² Power Technology Ltd, Ratcliffe on Soar Power Station, Ratcliffe, Nottingham, NG11 0EE, UK

³ Nottingham Centre for Pavement Engineering, School of Civil Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.

Fly ash, or Pulverised Fuel Ash (PFA) as it is known in the UK, has been used for over 50 years for a wide range of applications. With the recent upsurge of interest in the impact of industry on the environment, some have questioned using PFA as a construction material. This paper reviews existing knowledge and presents some recent findings of research on the environmental impact of PFA.

The chemistry of PFA reflects the mineral origins of the coals when formed millions of years ago. The combustion process concentrates these minerals. However, most elements are held in the glassy particles that are formed in the furnace. While the trace element composition may indicate potential for environmental effects, the available leachable elements are minimal. With proper design, unbound PFA can be used as a fill material posing only negligible risk, even to sensitive aquifers.

Recently, an examination of leachates adjacent to large PFA embankments of varying ages has been carried out by Nottingham University. This project has shown no significant contaminants associated with the PFA. It also reviewed the release of radon gas from PFA and reported there are no significant radiation risks. A generic environmental risk assessment, bringing together data from these reports, UK power stations, various environmental sources, research papers, etc also concludes there are no significant environmental risks associated with the proper use of PFA as a fill material. This looked at trace elements, poly-aromatic hydrocarbons, dioxins, phenols, etc.

This paper concludes that PFA is an environmentally harmless material that can be safely used in bound and unbound applications.

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