Overall & Specific Objectives

The overall aim of the EVAPOTREAT project is to evaluate the applicability of nature-based, on-site wastewater treatment systems in areas with low soil permeability where solutions specified in the current legislation (i.e. the 2021 Code of Practice for Domestic Waste Water Treatment Systems (PE ≤ 10)) involving soil percolation will not work.  The main focus will be on carrying out full-scale field trials using willow evapotranspiration (ET) systems in an appropriate climate and representative soils in order to provide data from which robust design guidelines can be developed for zero discharge wastewater treatment systems in such areas of Ireland. The research project, EVAPOTREAT will be completed over a 36-month timeframe.
The specific objectives are as follows:

  1. Establish the current state of knowledge with respect to alternative, low / zero effluent wastewater treatment, eco-sanitation and nature-based technologies via a combination of literature review and international contacts.
  2. Determine realistic crop factors for established willows grown in domestic wastewater from the continued long-term monitoring of existing mature field scale ET systems being used to treat on-site domestic wastewater in Ireland.
  3. Evaluate the water runoff quality from the existing open ET systems in periods following rainfall events and compare this to runoff from adjacent fields and flows in nearest surface water.
  4. Assess and quantify the water pollution impact of such open systems with respect to local receiving water quality in their respective low permeability areas.
  5. Design, construct and monitor new full-scale, partially covered, mounded ET willow systems in County Leitrim (in collaboration with the Local Authority) in order to minimise the predicted storm overflow from the systems and to quantify the realistic fraction of rainfall recharge that can be diverted away from the system using such a design approach.
  6. Model the willow ET systems with respect to water level and rainfall using a combination of simple water budget and more detailed finite element models.
  7. Synthesise the data from the fieldwork studies, as well as simulations from the numerical models, to produce robust design guidelines for zero discharge solutions (if feasible) for different geographic locations across the country, based on the concept of a mounded impermeable cover diverting a fraction of the rainfall off to the sides.

Evaluate the long-term environmental sustainability of these nature-based systems (compared to other more conventional on-site wastewater treatment systems) using Life Cycle Assessment methodologies. 

Project Team

The project is led by Professor Laurence Gill, Department of Civil Structural and Environmental Engineering, Trinity College Dublin who is the Project PI and experienced academic in wastewater treatment systems. He will work alongside:

  • Assistant Professor John Gallagher, Department of Civil Structural and Environmental Engineering, Trinity College Dublin (Experienced researcher in LCA (Life Cycle Analysis)
  • Joseph Gilhooly, Deputy Chief Executive and Director of Economic Development, Planning and Infrastructural Services, Leitrim County Council (key stakeholder as a county with large areas of low permeability subsoils)
  • Arne Backlund, Backlund ApS (International independent consultant and expert in alternative wastewater treatment and sanitation technologies)
  • Aaron Coyle, PhD Researcher, Department of Civil Structural and Environmental Engineering, Trinity College Dublin.
  • Post-Doctoral Researcher,(to be confirmed),  Department of Civil Structural and Environmental Engineering, Trinity College Dublin;

Project Outcomes

The overall objectives will be addressed in six work packages (WPs), as follows:
  • WP-1: Project Management
  • WP-2: Review of low discharge wastewater / eco-sanitation technology
  • WP-3: Monitoring of mature open willow ET systems
  • WP-4: Construction and monitoring of partially covered ET systems
  • WP-5: Synthesis (ET design guidelines and predicted impact)
  • WP-6: Communication, Dissemination and Knowledge Transfer activities


Contact Us

If you would like to find out more about the EVAPOTREAT project, please contact the project leader, Professor Laurence Gill, Department of Civil Structural and Environmental Engineering, Museum Building, Trinity College Dublin, The University of Dublin. College Green, Dublin 2, Ireland.