Waste Water Discharge. Licence Application. for. Portrane Donabate Rush Lusk Agglomeration.

Transcription

1 Waste Water Discharge Licence Application for Portrane Donabate Rush Lusk Agglomeration. Attachment A1: Non-Technical Summary.

2 WWDL_Application Portrane Donabate Rush Lusk: Section A1 Non Technical Summary Under the Waste Water Discharge (Authorisation) Regulations of 2007, Fingal County Council was granted a Waste Water Discharge Licence by the EPA, Licence No D , on 30 th October 2009 for the Portrane Donabate Agglomeration. In the application for that Licence, Fingal County Council highlighted that the Portrane Donabate Rush & Lusk Waste Water Treatment Scheme was in progress. This Scheme will ultimately collect sewage from the area shown on the accompanying drawing (CSO ) and transfer it to a new Waste Water Treatment Plant (WWTP) adjacent to the existing WWTP in the grounds of St Ita s Hospital. The new WWTP in under construction at present (Sept 11) and is expected to become fully operational in Q Fingal County Council is now applying for a Review of it s existing Licence, D , to take account of the new WWTP and the increased agglomeration size. Fingal County Council also proposes changing the name of the agglomeration from the Portrane Donabate agglomeration to the Portrane Donabate Rush Lusk agglomeration. The Portrane Donabate Rush Lusk agglomeration, as the name suggests, relates to the four towns and their immediate environs. The extent of the agglomeration is shown on the accompanying drawing. Also attached is a Scheme Schematic for the Portrane Donabate Rush & Lusk Waste Water Treatment Scheme. In the new Portrane Donabate Rush Lusk agglomeration are three former agglomerations: Portrane/Donabate, Rush and Lusk, as well as a large area about these towns which will eventually be serviced by a new network all feeding into the new Waste Water Treatment Plant at Portrane. This area includes the Turvey Cottages scheme. Parts of the new agglomeration has been previously licensed by the EPA as follows: Portrane/Donabate D th Oct Rush D nd Sept 2010 Lusk D st Nov 2010 Turvey Cottages A th Aug Balleally Landfill W st Dec 2009 The Licences and Certificate of Authorisation can be viewed on the EPA s website at Balleally Landfill is included as part of this application as Fingal County Council proposes to re-activate the leachate treatment plant there and pump the treated leachate into the sewer network feeding the new WWTP in Portrane.

3 There is an existing Waste Water Treatment Plant (WWTP) in the grounds of St Ita s Hospital, Portrane which treats sewage from the Portrane/Donabate agglomeration. This plant is at capacity. There is a septic tank and three temporary WWTPs in Lusk treating sewage from that agglomeration. Sewage from the Rush agglomeration is discharged untreated to sea. The septic tank at the Turvey Cottages is now used as a holding tank and is being emptied by tanker regularly. Leachate from Balleally is being tankered off site for treatment. A new WWTP is under construction (Sept 2011) adjacent to the existing WWTP in Portrane. This new WWTP will treat sewage from the three former agglomerations and will also cater for future development in these agglomerations as well as capturing areas which are at present being served by individual private on-site waste water treatment systems. The new WWTP has a design capacity of 65,000p.e. but current loading is expected to be 25,000p.e. The current loading is estimated as there are no flowmeters on the Lusk or Rush agglomerations. The discharge from the agglomeration is mainly domestic with some commercial. The foul water collection system includes gravity sewers and pumping stations which will direct the flows to the new Portrane WWTP. Phase I of the Portrane Donabate Rush & Lusk Waste Water Treatment Scheme consists of the construction of a new WWTP, three major Pumping Stations (PSs) and associated rising mains and gravity sewers. It is a Design Build Operate Contract with AECOM Design Build Ireland Ltd as the Contractor. The WWTP will be manned 9am to 5pm Monday to Friday, with a visit by operatives on Saturdays and Sundays. The plant will be fully automated with a system for dialling out to an operator in the event of an emergency outside normal working hours. The WWTP will be a CASS (Continuous Activated Sludge System) plant using four Sequential Batch Reactors (SBRs) to treat the influent. It will consist of an inlet works of inlet screening and grit removal. The screenings and grit will be washed and disposed of offsite. A flow proportional composite sampler will be located on the influent stream. The screened influent will be pumped to the SBRs which will have a cyclic routine of filling, aerating, settling and decanting. The final effluent will be discharged by gravity to the Irish Sea by a 600m outfall pipe with a 10 port diffuser at the discharge point. The total quantity discharged will be of the order of 5,625 cubic metres per day initially, increasing to 14,625 cubic metres per day ultimately. The discharged effluent is required to meet the standards set down in the Urban Wastewater Treatment Regulations (SI 254 of 2001) for BOD 5, COD and Suspended Solids. A flow proportional composite sampler will be located on the effluent stream before discharge, and samples will be tested for BOD 5, COD and Suspended Solids three to five times a week. There will be disinfection in the form of Ultra Violet (UV) sterilisation of the final effluent. The quantity of emissions to the receiving environment will be of the order of 5,625 cubic metres per day from the primary discharge initially. Eventually, the new WWTP

4 will treat the sewage from all of the old Rush agglomeration. However, at the start-up of the new WWTP, not all of Rush will be pumped to it, and a secondary discharge of raw sewage of the order of 2,000m 3 per day will continue until funding has been secured from the Dept of Environment, Community and Local Government to complete the required pipework and two new pumping stations. At present there is 1 Storm Water Overflow (SWO) and 5 Pump Station Overflows (PSOs) in the area covered by the new agglomeration. The SWO operates to relieve the Lusk treatment plant during periods of abnormally high flows in the sewers, generally associated with major rainfall events. The PSOs similarly relieve the pumping stations during periods of abnormally high flows or in the event of a power or mechanical malfunction. The overflows direct untreated sewage to streams, rivers or coastal waters. Initially there will be 5 emergency pump station overflows in the new agglomeration. There will be one storm water overflow. This will be located at the new WWTP and will protect the new WWTP in periods of abnormally high flows. Screened and degritted sewage will be diverted from the inlet works to a storm tank. If this fills, then the excess will escape via the primary discharge pipe to coastal waters. There will at least five further emergency PSOs in the future as funding is secured and the Portrane Donabate Rush & Lusk Waste Water Treatment Scheme is advanced. The leachate from the Balleally landfill site is being tankered off site at present for treatment. It is proposed to re-activate the leachate treatment plant at the site and pump the resulting treated leachate to the new WWTP in Portrane. Flows of the order of 150m 3 per day are estimated. The receiving environment is monitored. Bathing Water Quality is tested during the bathing season at the following designated bathing beaches: Rush South Beach, Brook Beach in Portrane, and Balcarrick Beach Donabate. Non designated beaches are also tested but more intermittently, at North Beach Rush and Tower Bay Portrane. All three designated bathing beaches met the Blue Flag criteria in 2010, and results to date in 2011 suggest that they will again meet the Blue Flag criteria in Of the non designated bathing beaches in 2010, Tower Bay narrowly failed to meet the Blue Flag requirements and North Beach Rush also failed. There is a program of testing ongoing in Rogerstown Estuary under the former Dangerous Substances Regulations. Routine monitoring is carried out by the EPA and the Marine Institute of the ambient waters off the coastline. The test results from the above testing indicate that the waters to which the Primary Discharge will discharge are achieving good status. Results of all this testing is included in Attachment E2 of this application. For the previous application for Portrane Donabate Agglomeration, a sample was taken at the non designated bathing beach of Tower Bay in Portrane and tested for

5 dangerous substances to assess the ambient conditions. The sample met the requirements. The results are included again. As the final effluent will meet the requirements of the Urban Wastewater Treatment Regulations, no significant effects are expected on the environment.

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7 Co en t ns of co For py in rig sp ht ect ow ion ne pu r r rp eq os ui es re o d nl fo y. ra ny he ru ot se.