Sligo Wastewater Treatment Works

Sligo, Ireland

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The Sligo Wastewater Treatment Works has been operated by Celtic Anglian Water (CAW) on behalf of Irish Water (previously Sligo County Council) since December 2008. The Works provides extensive treatment in the form of primary settlement, biological secondary treatment, final settlement and final recycled water UV disinfection. The Works accepts wastewater from a population equivalent of 50,000 from the town of Sligo and the grater county catchment area.

The Works also includes a Sludge Reception and Advanced Treatment facility which not only treats the sludges generated from the Works but also acts as a designated Sludge Treatment Hub for sludges from the wider county area.

Environmental and Ecological Awareness

The Works is located on a site within a bunded area of reclaimed marsh lands on the mouth of Sligo Harbour. This site has been designated as a Special Area of Conservation (SAC) which includes the estuary, sand spits and inter-tidal mud flats, all of which represent important habitats for migrant waterfowl, including brent & barnacle geese, and nationally important colonies of harbour seals and Great cormorants. Rare Bar-tailed godwit and golden plover feed in the shallow coastal mud flats.

The outfall transfers the recycled water stream to a location adjacent to the Cummeen Strand to Drumcliff Bay Irish Natura 2000 site. CAW ensures that the operations and performance of the Works is such that it is sensitive to and does not cause any harm to the ecology and the natural environment of the surrounding area.

Protection of Marine and Aquatic Life

Given its location adjacent to a Natura 2000 site, and the extent of bird and aquatic life in the environs the Works provides four stages of treatment for the wastewater, the final stage of which subjects the treated recycled water stream to UV disinfection providing a yet another stage of bacteriological content reduction as an added protection for the shellfish and aquatic life within Sligo Bay.

Wastewater is treated to the highest standards to protect the shellfisheries and natural environment of Sligo Bay.

A Hub Centre for Resource Recovery

The Works at Sligo includes an Advanced Sludge Treatment Facility incorporating sludge reception, thickening, blending, pasteurisation, digestion and de-watering. The final product from this process is classified as a Class A Biosolids which is then recycled as a nutrient rich organic fertiliser, to agricultural lands. The facility has sufficient capacity to allow the Works to become a Sludge Reception and Treatment Hub for sludges generated within the county.

Ecologically Sensitive

The plant also is home to the County’s Sludge Hub, receiving organic sludge’s for treatment from smaller works in Sligo, and neighbouring counties. Sludges are heat-treated and digested to make “Biocake” before being recycled as an organic nutrient rich fertilizer to agricultural land.