Case Study
Killala Wastewater Treatment Plant
OVERVIEW
Construction of a new Wastewater Treatment Plant (WWTP), pump station and pipework to serve Killala Town. Prior to completion of this project, wastewater from Killala was discharged untreated to Killala Bay, and thus completion of this project brings benefits to Killala in terms of health, integrity of the environment and improved water quality for fishing, watersports and marine life.
The new infrastructure ensures that wastewater is adequately treated and meets appropriate standards before being safely discharged into the marine environment. Delivery of the project was a key element in delivery of Uisce Éireann’s target of eliminating raw sewage discharges.
Benefits
Community:
Prior to completion of this project, raw sewage was discharged untreated onto the mudflats directly adjacent to Killala Town and directly into a designated SAC and SPA and impacting on shellfish waters. The commissioning of the first ever municipal wastewater treatment plant for Killala has had massive benefits on the water quality of Killala Bay which is renowned for its marine life and also for its watersports. The design of the wastewater infrastructure also allows for growth in the area, both in terms of residential growth and attracting jobs to the area. The selection of a site for the WWTP on a brownfield site at a largely disused industrial complex outside of the town was pivotal in ensuring local support for the project in a town renowned for its scenic beauty and cultural heritage.
Environmental:
In addition to Killala Bay being designated as SAC, SPA and shellfish waters, there are two designated bathing areas (Ross Strand and Enniscrone) in the vicinity. This brought significant challenges in terms of managing the statutory processes, selecting a suitable outfall location and determining an appropriate level of treatment.
To support this, detailed environmental assessments were required on the receiving waters as well as marine modelling and assessments. The project has resulted in improvements to all of these sensitive environments.
Sustainability:
The siting of the plant at the old Asahi industrial complex facilitated the use of the disused Asahi outfall pipeline to discharge effluent outside of the shellfish waters and SAC, thus allowing for less stringent treatment standards. Re-use of this outfall eliminated the requirement to install a new outfall in an environmentally sensitive location at considerable cost. Prior to selecting this option, Ryan Hanley commissioned specialist surveys to be undertaken on the existing pipeline to assess its condition and suitability for re-use.
BACKGROUND
Ryan Hanley (RH) was appointed in 2014 to advance the project through design, planning, procurement and construction. Prior to that appointment, RH (through a previous commission with Mayo County Council (MCC)) had undertaken works on preliminary design, site selection, site investigation and receiving water assessments
RH undertook the following services in delivery of this project:
- Preliminary Report – preparation of a Preliminary Report for MCC setting out the rationale for the scheme, assessment of options and recommended solution;
- Site Selection – undertaking a robust site selection process using multi-
criteria analysis to select an optimum site for the WWTP; - Marine Assessment – procurement of marine surveys and preparation of a Hydrodynamic Dispersion Model of Killala Bay to assess different potential outfall locations and their impact on the receiving waters. The modelling was critical in determining the level of treatment required and to demonstrate acceptable water quality standards at the designated bathing waters and s shellfish waters;
- Environmental Assessments – preparation of AA Screening, Natura Impact
Statement and Flood Risk Assessments to support the planning process;
- Wastewater Discharge Licence (WWDL) – preparation of the licence application together with supporting documentation;
- Planning – preparation of planning application documentation & successfully managing the planning process;
- Marine Outfall Pipe Assessment – procurement and management of specialists to undertake surveys of the existing Asahi industrial outfall pipe and assessment of its suitability for re use for discharge of treated effluent;
- Specimen Design – preparation of a specimen design for the WWTP site, pumping stations and pipelines;
- Tender Documents – preparation of tender documents (FIDIC Gold form of contract)
- Construction Management – undertaking the Employer’s Representative role during construction and commissioning;
- Project Management – overall management of the project from feasibility stage through through to handover.
