Page 54 - Council Journal Winter 2019

FEATURE Development in Poor Soils
New Technology To Allow
Development In Poor Soils
Environmental Engineer Joe Walsh looks at two technologies that can provide solutions for development of areas with sewage-related pollution.
The object was “to address these problematic areas and allow development, while protecting water resources from the risk of pollution by existing septic tanks in these areas”. This assessment of three technologies was completed by Trinity College in 2014 and the report was released by the EPA in January 2016.
Many areas of rural Ireland are classified as unsuitable for new development because of the health risks
for development. The domestic wastewater of approximately one- third of the Irish population, or approximately 500,000 dwellings, is treated on site by domestic wastewater treatment systems according to the EPA. Most of this is discharging to the subsurface soil, while the EPA also estimates that 39 per cent of the country has inadequate conditions for year-round soil treatment with the potential to pollute groundwater or surface water.
associated with sewage-related pollution. As a result, there is a pent-up demand for construction on farm homesteads and other unsewered sites, due to the absence of suitable wastewater treatment solutions in those areas.
Additionally, there are many existing houses on sites that would not meet current standards. Many of these will require upgrading in the future, particularly when there is a change of ownership, when the house is being extended or they fail an inspection under the Environmental Protection Agency’s (EPA) National Inspection Plan for Domestic Wastewater Treatment Systems. This article focuses on two technologies that can provide solutions for many sites previously considered unsuitable
The agency states that the areas presenting the greatest challenge are areas with: Inadequate percolation because of low-permeability subsoils; and/or Insufficient attenuation because of high water tables and shallow subsoils.
Technologies & Positive Recommendations
54 Council Journal
An evaluation project to assess innovative technologies and provide solutions specifically for areas of low permeability was funded by the EPA in 2011.
Low pressure pipe (LPP) pressure distribution systems: LPP systems use PVC pipe networks with a larger diameter supply manifold and perforated lateral pipes which are similar to existing pressure pipe systems in the EPA Code of Practice 2009 (CoP) for sand and soil filter beds and raised mound polishing fillters. The main system difference is
The project focused on three technologies: