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Castle Archdale Sustainable Wastewater Treatment Scheme

NI Water have completed an innovative new Integrated Constructed Wetland (ICW) at Castle Archdale, County Fermanagh.

The Castle Archdale site is the second ICW to be constructed by NI Water and represents an eco-friendly fully sustainable approach to wastewater treatment in the area. The wetland will now be available for the public to be at one with nature, enjoying the flora and fauna as part of the beautiful surroundings.

ICWs are designed, built and operated by man but are based on processes that occur naturally within indigenous wetlands providing an environment where the interaction of the wetland and the plants cleanse the wastewater. The investment has seen the construction of a series of shallow treatment ponds, the careful selection of plants providing the retention time and the capacity to treat wastewater from the Castle Archdale area.

Sara Venning, NI Water’s Chief Executive said:

“NI Water is pleased to be able to improve wastewater services for customers in the Castle Archdale area through sustainable projects like this. The new ICW will deliver improved wastewater treatment, whilst creating an aesthetically-pleasing area, rich in biodiversity, and potentially an educational resource.

“The ICW solution has been developed on natural treatment processes.  This is the second occasion that this method has been used in Northern Ireland and it is an important and significant step towards the development of more environmentally-friendly solutions to wastewater treatment throughout Northern Ireland.”

“I would like to thank all our stakeholders and elected representatives in the local community for their support throughout this project, particularly the Northern Ireland Environment Agency for allowing us to develop the wetland on this site.”

The new wetland can accommodate seasonal fluctuations in flow and is therefore ideally suited to the Castle Archdale area. The ICW method has an established record in Europe of providing a low cost, low energy and low maintenance alternative to mechanical wastewater treatment. NI Water believes that this natural environmentally-friendly solution will accommodate the future development needs of the Castle Archdale area, while promoting a natural ecosystem.


  • The Castle Archdale ICW contains just over 13,000m2 (3.25 acres) of wetland ponds.
  • Wastewater flows from the settlement pond through the densely planted treatment ponds under gravity flow. As the water progresses through each pond it becomes cleaner as pollutants are removed by natural biological processes.
  • Altogether the wetland planting comprises around 20,000 plants of emergent species within the treatment ponds and settlement ponds; native trees along the perimeter of the site and grass seeding, the most prominent plant species within the ponds are Iris pseudacorus (yellow iris), Glyceria maxima (reed sweetgrass), Typha latifolia (cattail) and Carex riparia (greater pond sedge).

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