Domestic-Type Effluent Discharges to Waters (Surface Freshwaters & Groundwaters)
Introduction
Kerry County Council has responsibility under the Water Pollution Acts for the licencing of discharges in County Kerry. As specified by legislation, licencing is required for all discharges of effluent to waters (both surface and groundwater), with one significant exemption, namely :
“ domestic sewage not exceeding in volume 5 cubic metres in any 24 hours which is discharged to an aquifer from a septic tank or other disposal unit by means of a percolation area, soakage pit or other method” – First Schedule,Local Government (Water Pollution)Regulations, 1978 (S.I. No. 108 of 1978).
This note has been prepared to give guidance and information on the issue of licencing for domestic-type effluent discharges in County Kerry.
Application Procedure
Copies of the standard application form and details of the application procedure are available on request from the Environment Department of Kerry County Council (Tel. 066-7162000). Completed applications should be forwarded directly by post to :
The Environment Department, Kerry County Council, Maine Street, Tralee, Co. Kerry.
Direct discharge of domestic-type effluent to surface waters (Freshwaters Only)
Kerry County Council will only consider the granting of licences for the direct discharge of treated domestic effluent to surface waters (freshwaters) in rare and exceptional circumstances. Discharges of this type should not, therefore, be generally considered for new developments. It is recommended that anyone considering making such an application should contact the Environment Department of Kerry County Council at the earliest opportunity to discuss the proposal.
Any application for the licencing of a domestic-type effluent discharge to surface freshwaters must be accompanied by the following information :
• Baseline chemical analysis data for the receiving waters – a minimum of 12 sets of sample results should be submitted. Samples should be gathered at regular intervals over a six month period (to include the month of August and September) at a point immediately upstream of the proposed discharge location. Details of the dates on which the sample were taken should be indicated. Analysis results should be provided for the following parameters : 5-day B.O.D., Molybdate Reactive Phosphate (MRP), Total Phosphorus (as P), Suspended Solids, Ammonia, Nitrate and Nitrite.
• Low Flow Assessment (95 percentile flow) – An estimation of the 95 percentile flow must be provided for the receiving waters. Where available, this should be based on historical hydrometric data obtained from the EPA, OPW or other reliable source. Where historical data is not available (ie. un-gauged catchments) in-stream flow measurement should be carried out at a location immediately up stream of the proposed discharge point. The method employed should be strictly in accordance with the relevant ISO Standard (ISO 748) or British Standard (BS 3680, Part 3A). Flow measurements must only be carried out following a period of prolonged dry weather, typically between the 1st July and the 30th September. On the same day, in-stream flow measurement should also be carried out on a gauged catchment of similar type (slope, geology, scale etc.) in the nearby area. The 95 percentile flow for the gauged catchment should be obtained from the relevant body (EPA, OPW etc.) and a comparison made between this and the in-stream measured flow (relative percentage). A determination of the 95 percentile flow for the receiving waters should then be made on a pro-rata basis. Full details of the calculations and method used must be submitted with the application. If possible, prior notification should also be given to the Environment Protection Section of Kerry County Council as to the proposed testing dates.
• Biological Assessment – An assessment of the biological rating for the receiving waters should be undertaken and a Q value submitted. The assessment should be carried out at a location immediately up-stream of the proposed discharge point. [Note : It may not always be possible to carry out a satisfactory biological assessment, particularly for watercourses with low or imtermittent flows. In such circumstances, a biological assessment should be carried out at the nearest suitable downstream location and the results submitted].
• Wastewater Treatment System - Details of the proposed treatment system and anticipated effluent quality and discharge volume should be submitted.
• Land Drains – details should be provided of the location and size of all land drains within the boundary of the site and/or in close proximity to the site.
• Detailed map – A detailed map (to scale 1:2500) showing the precise location of the proposed treatment system, the proposed discharge point, the location of the sampling point and the location(s) of any and all relevant land drains should be provided. A map to scale 1:50,000 (eg. Discovery Series) should also be provided, indicating the location of the proposed discharge.
• Assimilative Capacity – Details of the calculated assimilative capacity of the receiving waters and the anticipated cumulative concentrations in the proposed receiving water (based on the 95 percentile flow) should be provided for the following parameters : 5-Day B.O.D., MRP, Ammonia and Nitrite. Full details of all calculations should be included.
The above information is essential if an application is to be dealt with in a satisfactory manner. Failure to fully comply with the application procedure or to submit all information outlined above will, at a minimum, result in a delay in the application assessment process.
The information provided by the applicant must clearly indicate, on the basis of the assessment carried out, whether the proposed receiving waters are suitable for the discharge in question. Receiving waters which are shown, or are known, to be of poor or variable water quality, or where the proposed discharge may result in an exceedance of any relevant quality limits at the point of discharge, or downstream of the discharge point, would generally be considered unsuitable for discharge. In addition, the sensitivity of the catchment in question in terms of water quality will also be taken into account at the assessment stage.
Discharge of domestic-type effluent to Groundwaters
Applications for licencing of discharge of domestic-type effluent to groundwaters will only be considered where the following information has been provided :
• Wastewater Treatment System – Full details of the proposed treatment system, including details of any proposed percolation area/polishing filter, and anticipated effluent quality and discharge volume should be submitted.
• Land Drains – details should be provided of the location and size of all land drains within the boundary of the site in question and/or in close proximity to the site.
• Detailed map – A detailed map (to scale 1:2500) showing the precise location of the proposed treatment system (including any wetland, percolation area or polishing filter), the location of the proposed sampling point and the location(s) of any and all relevant land drains should be provided. A map to scale 1:50,000 (eg. Discovery Series) should also be provided, indicating the location of the site in question.
• Site Characterisation Data – Full details of the information obtained from the site characterization process should be provided as per the standard site characterisation form (Annex C – EPA Code of Practice “Wastewater Treatment and Disposal Systems serving Single Houses (p.e. < 10)”). The site characterisation procedure as outlined in the EPA Code of Practice “Wastewater Treatment and Disposal Systems serving Single Houses (p.e.< 10)” should be undertaken for every 150 square metres of percolation area / polishing filter proposed, or part thereof.
• Hydrogeological Report - a detailed hydrogeological report should be prepared and submitted in support of the application. This report, which should be prepared by a suitably qualified person, must include a detailed hydrogeological assessment of the site containing details of the following :
- An aquifer classification (ie whether the aquifer in question is considered regionally important, locally important etc.), - An assessment of groundwater vulnerability on the site (expressed as a vulnerability rating – extreme, high, moderate, low);
- Details of any groundwater supplies in the vicinity of the site (both public and private);
- An assessment of existing groundwater quality on the site and the likely impact of the proposed development on groundwater quality. As part of this process groundwater quality analysis should be carried out for the following range of parameters : Coliforms (both faecal and total), E-coli, Electrical Conductivity, pH, Ammonia (as ammonium), Chloride, Nitrate (as NO3), Nitrite (as NO2), Orthophosphate, Potassium, Sodium, Sulphate, Copper, Zinc, Lead.
The information and report provided with the application must clearly indicate, on the basis of a thorough assessment of the data gathered, whether ground conditions on the site are suitable for the discharge of effluent without causing adverse impacts on groundwater quality generally (reference should be made to the Interim Guideline Values produced by the EPA, or to any subsequent or amending values) and, in particular, without causing adverse impacts on any groundwater supplies in the vicinity of the site. The assessment should also indicate whether ground conditions on-site are suitable for the proposed discharge of effluent to groundwater without resulting in ponding or flooding on the site or in its vicinity.
Permit Assessment
All discharge licence applications received are assessed by Kerry County Council and, on completion of the assessment procedure, a recommendation on whether the applicant has been successful of not is made. In circumstances where a licence is to be granted, a set of appropriate legally binding conditions is applied. This may include an annual charge to off-set monitoring costs incurred by Kerry County Council.
Environment Department,
Kerry County Council,
October, 2006.
Contact Information
Environment Dept,
Maine Street,
Tralee,
Co. Kerry
Tel: 066/7162000
Fax: 066/7162001
Email: environ@kerrycoco.ie
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