Dr. Seán Ó hÓgáin:

This deals with waste water in reed beds. The diagram shows a hybrid reed bed, which is a combination of vertical and horizontal. It is a lined structure, with sand and-or gravel within it, so the groundwater cannot be contaminated. At the end of the bed, we have taken to putting in willows, which will take the discharge from the reed beds and it is then evapo-transpired. We end up with a zero discharge because the willows themselves transpire it. The diagram shows an example of one of the sites being installed in the South Dublin County Council area. Over a period of two years, we had no discharge at all from this wastewater treatment plant, which was in a county council depot with a Traveller halting site also contributing to it.