An investigation into the performance of highly permeable subsoils and reed bed treatment systems in treating domestic wastewater in Ireland

Abstract

In Ireland, domestic wastewater from over one-third of the population, or approximately 400,000 dwellings, is treated by on-site systems. Given that over 25% of all water supplies in the country is currently provided by groundwater, it is critical to protect this resource from contamination since the percolate released from on-site wastewater treatment systems enters the underlying groundwater which can, in turn, migrate under natural gradients toward points of exposure for receptors of concern, e.g. humans and drinking water supplies. Ireland’s Environmental Protection Agency (EPA) has published recommendations aimed at defining subsoil conditions that will provide an acceptable level of treatment for on-site wastewater in order to protect such groundwater resources from contamination. One of the crucial elements of this risk assessment approach is the percolation test.