April 2017 NUI Galway study raises serious questions about the application of wastewater treatment plant sludge to land

An NUI Galway-led study, which was funded by the Environmental Protection Agency, has raised questions over the continued application of wastewater treatment plant residuals (sewage sludge) to land.

Sewage sludge is a by-product of wastewater treatment processes, and up to 80% of sludge produced in Irish wastewater treatment plants is applied each year as fertiliser to agricultural land. This practice is not permitted in some other European countries.

The research project was led by Dr Mark Healy, Senior Lecturer in Civil Engineering at the College of Engineering and Informatics at NUI Galway, and comprised of researchers from the University, Teagasc and UCD. The study found that despite the many potential benefits of recycling sewage sludge to land, there are many risks, which include the presence of emerging contaminants and metals in sewage sludge and the potential for surface runoff of harmful contaminants into receiving waters. 

Speaking about the research findings, Dr Mark Healy at NUI Galway said, “This is a significant finding which may have implications for the continuation of this practice in Ireland. There is a possibility that contaminants present in sewage sludge, some of which are not currently regulated by legislation, may be applied to land, and may accumulate in the soils and enter the food chain.”

The results of this study have been published by the Environmental Protection Agency Research Report 200 entitled, ‘Health and Water Quality Impacts Arising from Land Spreading of Biosolids’.

To read the published EPA report visit: http://www.epa.ie/researchandeducation/research/researchpublications/researchreports/research200.html  

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