Ballykelly Sustainable Wastewater Treatment

Business, Public Sector • Causeway Coast and Glens

Upgrading Ballykelly's wastewater treatment facilities to use a more sustainable combination of traditional and natural processes.

  • Sara Venning (NI Water CEO) along with infrastructure minister Mallon.
  • Ballykelly WWTW with Solar Array (foreground) and ICW (background).
  • Student site visit with local companies - Maghera based BSG

Northern Ireland Water's story

NI Water has been working on a major sustainable solution to wastewater treatment which maximises the use of renewables as part of an integrated solution. This £5million investment to upgrade Ballykelly Wastewater Treatment Works (WWTW) provides a new sustainable wastewater treatment approach, utilising reed beds as part of the treatment process, providing a natural, long-term sustainable and resilient solution. This major investment also includes a 100kW solar energy system to help power the new works with solar energy.

The innovative solution delivered at Ballykelly includes a solar farm equipped with over 300 solar panels which will power the entire works during the summer months and be supplemented by the grid supply during the winter period. The marrying of traditional and natural wastewater treatment processes at Ballykelly not only provides a robust long-term solution for the village, but also provides an area rich in biodiversity to enhance the local land and water environment.

Offering the best of both worlds, the more traditional, mechanical side of the WwTW includes an inlet works, activated sludge plant, final settlement tanks and return activated sludge pumping station. These processes are controlled by a state-of-the-art mechanical control centre (MCC) and powered using solar means. In a further sustainable move, the backup generator provided for the works has been recycled from another NI Water site.

Once the wastewater has made its way through the mechanical processes, the effluent gravitates to the ICW where it is refined and polished to produce the highest quality discharge.

With a variety of native planting, the ICW creates a wide range of vegetative habitats for macroinvertebrates such as mayfly and stonefly to survive and for wildfowl to nest providing enriched biodiversity in the area.

The Ballykelly WwTW site also includes a dedicated area for trialling wastewater treatment innovations to help enhance NI Water's process selection in the future. The facility includes access to raw sewerage entering the works, power and an area of hardstanding suitable for a containerised trial system to be installed. The custom-designed facility provides NI water and suppliers with the opportunity to test innovative new processes and equipment in a safe environment, as any outputs can be safely returned to the head of the main treatment works.

Useful learnings from Northern Ireland Water

The NI Water journey piloting Integrated Constructed Wetlands (ICW) commenced over five years ago with a number of visits to ICW's in the Republic of Ireland. NI Water staff organised a visit involving the local community from Stoneyford, which resulted in the community embracing the first pilot ICW being constructed in Northern Ireland.

The initial solution at Stoneyford was for the entire treatment solution but NI Water has had challenges achieving the final ammonia effluent standard, so a traditional polishing solution has been added.

With Ballykelly being a much larger population than Stoneyford a traditional aeration plant has been constructed with the ICW process providing the final polishing for the effluent.

Students from local companies - BSG Civil Engineering, Doran Consulting and RPS - got an opportunity to visit the site as part of a recent training day. Future educational visits in the local area are also planned.

Northern Ireland Water's metrics

Cost of energy per volume and load (population equivalent) of treated wastewater compared to other wastewater facilities.
Amount of solar energy produced (100kW).
Cost savings.

Feeling inspired? Discover more about this story...

Response to climate crisis

Mitigation & Adaptation




Business, Public Sector, 250 to 10,000 people

Shared by

Northern Ireland Local Government Association

Updated Feb, 2024

Recommended for you

  • Hay Community Assemblies

    Hay Community Assemblies

    Running community assemblies to make better decisions that serve the needs of all.

    Buildings & Places
  • NWG Innovation Festival
    Newcastle upon Tyne

    NWG Innovation Festival

    Finding innovative solutions to water industry challenges.

    Buildings & Places
  • Canopy Housing

    Canopy Housing

    Providing housing, training and green-building skills through a retrofit programme in Leeds.

    Buildings & Places
  • Slow The Flow Calderdale

    Slow The Flow Calderdale

    Advancing public education in nature-based methods of managing flooding.

    Buildings & Places