Ireland's State of the Environment Report 2024

344 Chapter 13: Environment and Industry Emissions to water Industrial pollutant emissions can impact both surface water and groundwater. Emissions from industry to surface water can be direct – from an on-site waste water treatment system or stormwater drainage network – or indirect, via sewers, subject to consent from Uisce Éireann, for discharge into its sewer and subsequent treatment in an EPA-regulated municipal waste water treatment plant. The impact that emissions from industry can have on water depends greatly on the nature of the water into which the pollutant is discharged. The effect that pollutants may have on surface water can be measured by examining physical, chemical and biological impacts. Surface water. In Ireland, industrial emissions to surface water are not a main pressure on water quality when compared with the emissions of other sectors. As discussed in Chapters 8 and 9, emissions from industry rank ninth out of 11 significant pressures on water quality. Industry’s impact on water quality is far less than that of other sectors, as industrial facilities that discharge to surface water have emission limit values with which they must comply. Where they have failed to comply with their emissions limit values, installations may have negatively impacted surface water quality by depleting oxygen levels and/or having toxic effects on aquatic life in receiving waters. Industrial pollutant releases to surface water include compounds that contain nutrients such as nitrogen (referred to as total nitrogen) and phosphorus (total phosphorus) which can cause eutrophication in surface waters. Releases are also described in terms of their total organic carbon content. High levels of organic content in a natural water body will undermine an ecosystem’s operation by, for example, affecting oxygen levels in the water. The IED permits issued by the EPA to operators set out limits for emissions to water that ensure that industrial activities do not have detrimental effects on the receiving environment. Emissions to water from industry can be direct or indirect via sewer and urban waste water treatment plants, as illustrated in Figure 13.6. Figure 13.6  Direct and indirect releases of treated waste water to water from industrial sites Industrial plant Industrial plant Urban area Indirect release Urban waste water treatment plant On-site industrial waste water treatment plant Direct release Direct release from UWWTP Direct release Indirect release UWWTP, urban waste water treatment plant.