Urban Waste Water Discharges in Ireland for Population Equivalents Greater than 500 Persons - A Report for the Years 2006 and 2007

Summary: This report provides a reveiw of the treatment of waste water at villages, town and cities in Ireland and the quality of discharges from secondary waste water treatment plants with a population equivalent of 500 or more during 2006 and 2007.

Published: 2009

ISBN: 1-84095-058-8

Pages: 94

Filesize: 1,717KB

Price: Free to download / €25 for a printed version

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This report provides a review of the treatment of waste water at 482 villages, towns and cities in Ireland and the quality of discharges from 370 secondary waste water treatment plants with a population equivalent of 500 or more during the reporting period 2006/2007. The overall findings show that there is none or inadequate waste water infrastructure at 112 locations and there are 192 treatment plants (51%) where the effluent quality is not meeting the EU standards due to waste water treatment plants either not operating properly or being overloaded. 

EPA biological monitoring in 2007 identified 13 seriously polluted river sites that can be attributed to urban waste water discharges.  In addition, 7 bathing water areas failed the EU mandatory limits during 2006/2007 due to the impact of waste water discharges.

While there has been significant investment in waste water infrastructure in Ireland over the past decade, the level of infrastructure has to increase and be deployed at a faster rate to:

  • Meet the EU standards;
  • Prevent the pollution of rivers, lakes, estuaries and bathing water;
  • Protect drinking water supplies.

In addition, the management of waste water treatment systems needs to improve as a quarter of the non-compliances are attributed to insufficient sampling.

Level of Treatment of Waste Water

In 2007 the level of treatment provided was as follows:

  • 4% of waste water arisings did not receive any form of treatment;
  • 5% of waste water arisings received preliminary treatment;
  • 1% of waste water arisings received primary treatment;
  • 75% of waste water arisings received secondary treatment;
  • 15% of waste water arisings received nutrient reduction in addition to secondary treatment.

At the start of 2008, waste water from 112 locations with a population equivalent of 500 p.e. or greater was being discharged with either no treatment or basic treatment, and in most cases was discharging to estuarine or coastal waters.

Of the 158 locations requiring secondary treatment or higher by theDecember 2005 deadline set by the Urban Waste Water Treatment Directive, the required level of treatment was not in place at 28 of these agglomerations at the end of 2007. 

Level of Operation of Waste Water Plants

In 2006/2007, non-compliance for the very large plants increased by 16 per cent over the previous reporting period, while the majority (81%) of smaller treatment plants did not comply with the required standards.  One-in-five plants failed to take an adequate number of samples in 2007.

Level of Impact of Waste Water Discharges

In 2006 and 2007 the EPA audited 22 local authorities, the following recurring problems were identified:

  • Inadequate collecting systems for waste water (e.g. poorly performing combined sewer overflows);
  • Insufficient treatment capacity;
  • Insufficient sampling frequencies;
  • Poor effluent quality;
  • Poor assimilative capacity for effluent in some receiving waters, and;
  • Poor sludge management on site. 

Recommendations

In order to achieve compliance with the requirements of the Urban Waste Water Treatment Regulations the EPA makes the following recommendations.

 Level of Waste Water Treatment in Place

  • Eliminate untreated discharges – The discharge of untreated waste water to the aquatic environment should be stopped and local authorities should install appropriate treatment at the 112 locations where waste water is being discharged with either no treatment or basic treatment.
  • Complete infrastructure works – Local authorities should as a priority provide secondary treatment for the 24 locations identified in Table 2-1 that remain without the required level of treatment.

 Level of Operation of Waste Water Plants

  • Monitoring Local authorities should ensure that monitoring and analysis is carried out in accordance with the Regulations.
  • Operation of treatment plants – Local authorities should review the operation, maintenance and management of urban waste water treatment plants.

Level of Impact of Waste Water Discharges

  • Target plants impacting on water quality – Local authorities should in particular target corrective action programmes at plants that are polluting rivers, lakes and sensitive receptors such as bathing waters.
  • Measures under the Water Framework Directive – At-risk waters as defined by the Water Framework Directive, should be a priority for protection. Failure to control the discharges into sensitive or protected areas will damage sensitive species, habitats, water abstractions, fisheries, shellfish production or spoil recreation.

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