Noel Dempsey
Question:2 Mr. Dempsey asked the Minister for the Environment the plans, if any, which are proposed for the disposal of sludge from Mutton Island, County Galway. [3438/96]
Ceisteanna—Questions. Oral Answers. - Mutton Island (Galway) Sludge Disposal.
David Andrews
Question:35 Mr. Andrews asked the Minister for the Environment the plans, if any, which are proposed for the disposal of sludge from Mutton Island. [3343/96]
I propose to take Questions Nos. 2 and 35 together.
Detailed sludge management arrangements for the Galway secondary treatment plant are at present being finalised by Galway Corporation in accordance with my recent authorisation to advance the design of this plant.
As already determined by the EIA process, sludge management at Galway will involved anaerobic digestion to produce methane for power generation, together with dewatering to yeild a product with dry solids in the range of 23 per cent to 35 per cent. This product would be transported from Mutton Island in sealed containers, involving an estimated 14 trips per week.
The original intention was to dispose of dewatered sludge at the Carrowbrowne landfill. However, it was always accepted that this disposal route should be contingent on the conclusions of a review of that landfill facility to be carried out by Galway Corporation. That review has now established that there is limited further landfill capacity at Carrowbrowne, which cannot therefore be relied upon for the disposal of sewage sludge.
In order to promote the maximum re-use of sewage sludge as a secondary raw material, in accordance with the requirements of the EU Directive on Urban Waste Water Treatment, my Department circulated an advisory strategy document on sewage sludge management to local authorities in June 1994. This envisages, in the case of Galway city, the re-use of all dewatered sludge by landspreading on suitable forestry plantations and farmland. I anticipate that the detailed sewage sludge management arrangements to be finalised by Galway Corporation will have regard to this recommendation.
Can the Minister confirm unequivocally that the transport of sealed containers of waste sludge from Mutton Island will entail only 14 trips per day?
Per week.
For how long will that continue? It is my understanding that the number of trips will considerably increase during the next five, ten or 15 years. Would he also confirm that the route from Mutton Island to the Carrowbrowne landfill site runs through the centre of Galway city?
The plan was designed to cater for the anticipated population growth and development needs of the city of Galway, on which our estimate of 14 trips per week is based. At some future date, if there is a huge growth in the population of Galway, that might increase. As the Deputy will appreciate, to cater for a population of 68,000 people will require 14 trips per week, or two trips per day, taking the dewatered sludge from the treatment plant at Mutton Island and disposing of it. With proper traffic management flows, the route to be taken can be planned. However, no matter where the treatment plant is located, the sludge has to be removed as under European law since 1988 we are no longer entitled to dump it at sea. The best environmental policy is to use it as a secondary material by way of landspreading, a proper nutrient that would be of benefit to forestry plantations. This has to be worked out in some detail before the plant becomes operational.
What is the lifespan of the Carrowbrowne landfill site? In the meantime, bearing in mind what the Minister said about spreading the slurry on land at a later stage, has he any alternative site in mind to the Carrowbrowne site, or had consultations with Galway County Council about an alternative when its lifespan expires?
I indicated that I do not believe the Carrowbrowne site would be suitable, that it is nearing the end of its useful life. Although that was the proposal in the original environmental impact assessment, we have advanced in terms of our attitude to sludge. The volume of sludge to be disposed of in Ireland will increase substantially as more treatment plants become operational and we can no longer dump raw sewage into our coastal zones. We will then approach European norms in terms of the quantities of treated sludge — a secondary raw material that is a good nutrient for such practices — to be land-spread.