Percolation tests for site assessment for domestic wastewater treatment systems

Project AttributeProject Details
Project TitlePercolation tests for site assessment for domestic wastewater treatment systems
EPA Project Code2019-W-DS-35
Lead OrganisationUniversity of Dublin, Trinity College (TCD)
CoordinatorLaurence Gill
EPA Research 2014 – 2020 Theme(s)Water: Theme 4: Understanding, Managing and Conserving our Water Resources
EPA Research Pillars
Project Start and End DatesStart: 02/03/2020
End (if applicable): 01/03/2021
Revised End Date (if applicable): 01/06/2021
EPA Project TypeDesk Study
EPA Award TypeSTRIVE – Project Based Awards
Current Project StatusGrant Awarded
Total Funding Amount90131.20
Project Abstract/DescriptionThis research will evaluate different methods of how to assess the percolation characteristics of soils as part of the site assessment process used for the design domestic wastewater treatment systems (DWWS). Currently, site assessment (and subsequent DWWTS design) is prescribed in the EPA Code of Practice (EPA, 2009) which requires an on-site falling head percolation test, known nationally as the T-test, to be carried out. However, this method has limitations for more low permeability subsoils and so an alternative method needs to be evaluated. Several different approaches can be taken to determine a soil’s saturated hydraulic conductivity, either by percolation tests (carried out in the laboratory or in the field) or via soil size distribution analysis. The project will focus on a review of the different methodologies used internationally and also provide a clear explanation of the theoretical background for water percolation. It will then investigate the Irish situation specifically and translate the existing data / findings in to a proposed new approach to site assessment and associated percolation testing, in addition to how it might be incorporated into the Code of Practice, in order to overcome the issues with the existing falling head test for low permeability subsoils. As set out in the Communication Plan (see Section C of the proposal) the project will produce the following: a Final report for the EPA, a minimum of 1 peer-reviewed publication in a high quality international journal, and a database of over 800 falling head test and around 20 constant head percolation tests carried out across the country which will be compiled for EPA and stored on its Research Data Archive (SAFER). In addition, the project will set up a Stakeholder advisory group of members hopefully representing the following organisations: EPA, Local Authority Waters Programme (LAWPRO), Local Authorities, An Bord Pleanala, Geological Survey Ireland, Site Assessors, National Standards Association of Ireland (NSAI), Irish Onsite Wastewater Association (IOWA), Irish Water Treatment Association (IWTA), National Federation of Group Water Schemes (NFGWS) and Irish Water.
EPA Scientific OfficerKarenRoche

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