Composition and distribution of organic waste in Ireland : implications for land application practices

Questions about the economic and environmental sustainability of current waste management scenarios in Europe for various organic wastes, the policy drive at the EU, and the subsequent adoption of EU policy at national levels, has given momentum for diversion of organic wastes away from landfills and ultimately on to the land. The land has always been the receptor of choice for animal manures, but it is now becoming a popular management route for other organic wastes. Currently in Ireland, land is examined by specific sectors and regarded as a resource available uniquely to each sector. In contrast, it is reasoned in this paper that treating the diverse organic wastes potentially suited for land application as a unit waste stream and developing a detailed accounting of waste quantities and characteristics would serve as a gateway towards a consistent and holistic strategy from which a comprehensive land application strategy at national level or regional level could be developed. The methodology used is a desk-based inventory that relied on existing secondary data in published reports. A literature based survey and quantification of organic wastes potentially suited for land application, in Ireland, was completed. The survey included a broad range of organic wastes from agricultural and non-agricultural activities - with animal manure, spent mushroom compost, biodegradable municipal waste, biosolids, sludge from onsite treatment plants, organic wastes from industrial sources the major ones. Reports from the Central Statistical Office of Ireland, study reports at the Environmental Protection Agency, Regional Waste Management Plans, Sludge Management Plans, County Waste Registries and European sources were consulted in association with codes and guidelines to determine the quantity and composition of organic wastes potentially suited for land application. Major and minor plant nutrients were used as a basis to describe the composition of the organic wastes. Finally a GIS-based database of the organic wastes potentially suited for land application was developed and a distributional analysis was performed at different spatial scales. Results of our analysis confirm that animal waste remains the largest source of organic waste in Ireland - as in most other European countries - and the major concern for management through land application due to the sheer volume of the waste. Between the small percentage of organic wastes of non-animal origin biosolids, sludge from industrial sources, biodegradable municipal wastes and spent mushroom compost constitute the major share. There is a spatial distribution of the organic wastes in terms of both the total quantity of organic waste and type of the organic wastes. While the volume of the non-agricultural wastes appears to be insignificant – compared to organic waste of animal origin – at a National level it constitutes a high local problem at lesser spatial scales, i.e. counties and regions. The research suggests that there is a need to a leap from the present, sector-specific approach used in managing the land application of waste to a comprehensive land application strategy that considers the total quantity and quality of waste relative to the land base suitable for receiving them.