Untreated Sewage

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Escherichia coli (Rocky Mountain Laboratories) (Image Credit: www1)

Sewage is defined as waste water and excrement conveyed in sewers, and is a cause for concern due to its contribution to the proliferation of algal blooms in bodies of water. Untreated sewage also contains a host of harmful bacteria that can be severely detrimental to human and environmental health. Microbes like Escherichia coli (bacterium commonly found in the lower intestine of warm-blooded organisms) can enter the water column and be taken up by commercially farmed (and wild) shellfish. Any shellfish which exhibit unsafe levels of E. coli in their tissues, are deemed unfit for human consumption and cannot be sold. This can impact on commercial companies with some Irish seasonal markets being affected significantly in July 2015 (EPA, 2015).

In 2015, the EPA reported that raw untreated sewage was being discharged into 45 rivers, lakes and coastal areas around the state, leading to poor quality water which could pose a risk to human health and the aquatic environment (EPA, 2015, p.4). Some discharged bodies of water had received preliminary treatment which entails “a basic form of treatment typically designed to remove floating debris, oils, fats, grease, grit, rags and large solids from the raw waste water” (EPA, 2015, p.29; Gleeson, 2015), however raw, untreated sewage was being deposited directly into waterways which has been linked to the poor quality of water at a number of bathing sites across the Irish coastline.

Aerial View of Ringsend Wastewater Treatment Facility (Image Credit: www2)

In 2016, O’Brien reported that an independent monitoring of 263 treatment plants established that 71 failed to comply with effluent quality standards stipulated in their licences (EPA, 2015, p.ii). Since the publication of the EPA report, two additional treatment facilities have been built at locations that failed to comply with treatment regulations, however 12 areas have currently failed to meet their deadline for improvements which has lead to further pressures from the EU Commission (O’Brien, 2016). The results of the most recent EPA report indicated that, “less than half (44%) of improvement works due between 2009 and 2016” however notable improvements have occurred includeing “the commissioning of new treatment plants at Carrigtwohill, County Cork and Kilmacthomas, County Waterford” (EPA, 2017, p.15).

To learn more about water quality you can visit the Environmental Protection Agency website where you will find useful infographics on environmental issues such as domestic waste water management or national bathing water quality. You can also review the quality of bathing waters in your area by exploring this SPLASH interactive map.


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