Eoin Ryan
Question:5 Mr. E. Ryan asked the Minister for the Environment when his Department will consider tertiary treatment for the sewerage works at Ringsend, Dublin 4. [2349/95]
Ceisteanna—Questions. Oral Answers. - Ringsend (Dublin) Sewerage Works.
Planning of the improved sewage treatment and disposal facilities required for the Dublin area under the Urban Waste Water Regulations, 1994, is now at an advanced stage within Dublin Corporation. My Department is awaiting the submission of these proposals from the corporation.
I have already made it clear at a public ceremony in Dublin that I do not rule out the provision of nutrient removal facilities, such as denitrification at Ringsend if the detailed planning for the project shows this to be necessary.
I should point out that, in strict terms, the provision of tertiary treatment is unlikely to be an issue in relation to Ringsend or other coastal discharges. Tertiary treatment represents the most advanced biological process for reducing biochemical oxygen demand and suspended solids from a discharge. As such, it is appropriate to inland discharges to water bodies with a small dilution factor.
The discussion regarding Dublin Bay has been about the extent of nutrient removal facilities, over and above normal secondary treatment, which may be required to reduce particulate nitrogen in receiving waters. Nutrient removal, rather than tertiary treatment, would be an appropriate means of achieving extra reduction, if required.
I am determined to achieve the best possible water quality in Dublin Bay. If assessment of the detailed proposals to be submitted by Dublin Corporation shows that further denitrification over and above secondary treatment is required, I will be well disposed to providing this.
I take this opportunity to congratulate the Minister and the Minister of State on attaining their ministerial posts and I wish them well.
I am surprised the Minister is ruling out tertiary treatment in respect of sewerage works in Ringsend, as I understand such treatment is still under consideration at local level. Having regard to the amount of sewage being piped into Ringsend, there is a good deal of concern regarding how effectively the sewerage works can treat it and there is a demand for the best available, as opposed to the best possible, technology. I accept what the Minister said, but he should reconsider the matter because if a greater amount of sewage is disposed of in Ringsend it is important that it is properly treated. The sewage in that part of Dublin Bay can be held in by tidal patterns and so on and if it is not treated properly it could have a significant impact on the bay.
A comprehensive and expensive plan is underway. We have not got detailed costings yet because the proposals are not finalised, but it will cost well in excess of £200 million, probably in excess of £250 million. There is a clinical definition of "tertiary treatment" which is not required in respect of the sewerage works, but a post-secondary treatment, which some people characterise a tertiary treatment, may be required. Depending on the detailed submissions I get from Dublin Corporation and on their analysis, I am well disposed to providing the best possible treatment works to ensure we have the best possible water quality in Dublin Bay.
I welcome the Minister's clarification of tertiary and post-secondary treatment. Will he indicate the impact on water activities of the sewage being washed into the bay and how it will affect Dollymount Strand's chances regarding blue flag status?
Under the urban waste directives we are required to have minimum secondary treatment of all coastal discharges by the year 2005. Most of our coastline already qualifies for blue flag status and after the envisaged treatment works are completed, I have no doubt all the coastal waters around Dublin will qualify.
Dollymount does not.
Will the Minister distinguish between tertiary and secondary treatment with denitrification so that people are not confused? What time-scale will be involved in the completion of such a project? Also, following speculation in the media, when can we expect Dublin Bay to be designated a sensitive area under the European Union Directive on urban waste water. I understand the Dutch coastline is already designated as such. If all the sewage is piped into Ringsend, does the Minister accept that with secondary treatment eutrophication will be a major problem? Is that why he proposes tertiary treatment rather than denitrification only?
We should not go beyond the subject matter of the question.
The Deputy posed a number of questions. The Irish authorities took a careful precautionary approach to designation in regard to urban waste water. We have not designated any coastal waters as less sensitive, whereas the English and Welsh have, including coastal areas along the Irish Sea. No area along the Irish coastline has been designated less sensitive requiring only primary treatment. We have acted in a precautionary manner in the context of designation.
In regard to what constitutes tertiary treatment. I am advised that a clinical definition of such treatment represents the most advanced biological process for reducing biochemical oxygen demand and suspended solids from a discharge. I do not believe we necessarily need that level of filtration for an outflow into open waters. However, it would be required in the case of inland waterways where the mechanism for dispersal would not be similar to that for the open sea. However, I am reminded to consider carefully proposals from Dublin Corporation that need post secondary treatment to ensure that the type of suspended solids or eutrophication to which the Deputy referred would not exist after the treatment plant is put into operation.
I join with other Deputies in wishing the Minister and his colleagues well in their new posts. Will the Minister indicate whether the decision on the level of treatment — primary, secondary or tertiary — is a reserved or an executive function of a local authority.
Under the European Union Directive on waste water we are required to provide a minimum of secondary treatment in designated areas unless they are designated less sensitive. As I already indicated, there are no coastal waters around Ireland thus designated. In essence, under European regulations by the year 2005 all coastal discharges will have to be at least of a secondary treatment standard. Where it is deemed appropriate, I am willing to consider post secondary treatment.
In reply to a question from Deputy Sargent, the timeframe for this project is set in the European Union directive. This is a complex and expensive programme but we will work hard to have it completed within the time frame specified in European law.
Given that the Minister broadened the spectrum and referred to the programme of work for coastal waters — I have a particular interest in Cork — in the context of secondary treatment, is it possible that in a short number of years a regulation could be introduced making it necessary to provide tertiary treatment for all schemes? Will the Minister——
I hesitate to interrupt the Deputy but this question refers solely to sewerage works at Ringsend, Dublin 4. I cannot allow an extension of that question and the Deputy knows that.
My question also relates to Ringsend.
The Deputy heard the ruling of the Chair. I will not permit an extension of the question. If the Deputy wishes to put down a question appertaining to Cork he may do so.
Will the Minister acknowledge what I have said and outline the difference in cost between providing secondary and tertiary treatment for the project? As I understand the difference is not significant, perhaps the Minister might examine the feasibility of tertiary as opposed to secondary treatment.
Given that I have said there should be no extension of the question, I will allow the Minister to reply.
I will endeavour to adhere to the Chair's guidance. Post-secondary treatment is obviously less expensive than tertiary treatment. In a clinical sense tertiary treatment can work out expensive depending on the scale of the project and the one proposed for Dublin is large. There is a cost factor involved in denitrification, the details of which I will provide if the Deputy tables a separate question.
Whether tertiary treatment or otherwise is used, before all our sewage is pumped into the sea at Ringsend, will the Minister ensure the project works properly?
A final decision in relation to a single plant has not been made as yet; there could be two plants. If it is recommended that we establish a central plant in Dublin, I am confident the engineers will assure me it will work to the specifications and cost indicated.
By allowing the northern fringe pipeline into Ringsend, are we more or less designating the inner bay as less sensitive? The Minister said he has not designated any waters as less sensitive. However, as the Dún Laoghaire pipeline runs into Ringsend and it is proposed to allow the northern fringe pipe to do likewise, in effect, are we not sacrificing the inner bay? If tertiary treatment is ruled out perhaps we should consider running the northern fringe pipeline into a plant at the nose of Howth which has been the case up to now.
Less sensitive designation would require only primary treatment. There are no areas designated less sensitive. Consequently, there would be no discharges that would not be treated at least at secondary level. The question of less sensitive areas does not arise in the context of Ireland.
In terms of post-secondary treatment, whatever is needed to ensure the highest possible quality of water in Dublin Bay will be done. I will await a submission from Dublin Corporation engineers before making a decision on the final proposals.