The absolute decoupling of nutrient emissions from the domestic sector and population growth, over a period of almost two decades (1990-2011), is observed in fourteen countries (Austria, Belgium, Czech Republic, Germany, Denmark, Greece, Finland, Ireland, Malta, the Netherlands, Norway, Portugal, Slovenia and Turkey). The actual extent of decoupling, and the differences in trends among countries, may be partially explained by the different numbers of inhabitants connected to tertiary wastewater treatment technologies.
When making an EU wide comparison of the extent of decoupling of nutrient emissions from population growth, the actual proportion of the population connected to different types of wastewater treatment (elaborated in indicator CSI 024 ) and the completeness of data available on the population connected to collecting systems without treatment should be taken into consideration. The implementation status of the Urban Waste Water treatment Directive (UWWTD), which protects the water environment from the adverse effects of discharges of urban waste water, as well as the level of investment in water and wastewater management, may have an impact. Similarly, the implementation status of the Water Framework Directive (WFD) and Groundwater Directive may also have an impact. Furthermore household patterns and household income level affect the production and composition of wastewater and should also be considered.
It is assumed that the use of actual data on loads discharged from wastewater treatment plants, combined with the load values calculated for the population not connected to wastewater treatment, would add value to the decoupling indicator as it would better reflect the real situation.
Data and maps
Emission intensity of the domestic sector in Europe