Enda Kenny (Mayo, Fine Gael)
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Question 351: To ask the Minister for Agriculture and Food the research and analysis his Department has carried out on the relevance of anaerobic digesters as an assistance to dealing with pollution in the river system; if his Department has examined the potential of combining anaerobic digesters with reverse osmosis membrane technology in the delivery of pure water; and if she will make a statement on the matter. [17958/05]

Mary Coughlan (Donegal South West, Fianna Fail)
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A possible role for anaerobic digesters in dealing with organic waste from the both the agricultural and agrifood sector and, in particular, from the pig and poultry sectors has been under consideration by my Department for some time. Some years ago my Department grant aided an anaerobic digestion facility on a pilot project basis with a view to examining its feasibility and potential to process livestock manure. My Department's examination of the issue has continued over recent years in the context of the national climate change strategy, October 2000, and more recently in the context of water pollution and the nitrates action programme. The evaluation of anaerobic digestion to date indicates that while it is a proven technology applicable to the processing of livestock manure, its economic feasibility is dependent on a number of factors including sources of high-energy feedstock for co-digestion, price support for green energy and-or a viable outlet for excess heat produced as an offshoot of electricity production.

As a stand-alone process, anaerobic digestion has a limited potential for improving water quality as it does not reduce the volume or nutrient content of slurries. To reduce the volume or nutrient content of slurries, anaerobic digestion would need to be combined with some other treatment technology. The removal of water from digestate using reverse osmosis technology has been suggested as a way to address this issue. However, while reverse osmosis is a proven technology for the treatment of water, its suitability for the further processing of digestate has not been fully established.

An additional factor with implications for the financial viability of anaerobic digestion in Ireland is legislation governing the type of animal-derived wastes that can be digested and spread on land. Ireland's requirements, which are stricter than those laid down by the EU, are designed to ensure the safety of consumers of beef and to prevent the exposure of cattle to the infective BSE agent through feed. The need to prevent the spread of this disease has been of central importance to Ireland since its discovery here in 1989. As a result, high-energy abattoir wastes or other wastes containing meat cannot be anaerobically digested if the resulting digestate has to be spread on any land, which is almost always the case. These restrictions are currently under review in my Department.