Indicator Fact Sheet

Emissions of nitrogen (N) and phosphorus (P) from urban wastewater treatment (UWWT) plants

Indicator Fact Sheet
Prod-ID: IND-258-en
  Also known as: WEU 009
This page was archived on 08 May 2015 with reason: No more updates will be done

Assessment made on  01 May 2004

Generic metadata



DPSIR: Driving force


Indicator codes
  • WEU 009

Policy issue:  Are discharges of nutrients from urban waste water treatment plants being reduced?


Key assessment

During the period 1970 to 2000, several countries showed a marked increase in the percentage of population connected to urban waste water treatment plants, especially those employing tertiary treatment involving the removal of nutrients. In the European countries included in Figure 1, the percentage of population connected to tertiary treatment increased from almost 0 to 70 or 80 % depending on the country. Over the same period the discharge of phosphorus and nitrogen from waste water treatment plants decreased by 70 % and 50 % respectively. This difference reflects the fact that nearly all the tertiary treatment plants employ phosphorus removal whilst only some of the plants, in particular the large plants, employ nitrogen removal. These results can be linked with the objectives of some of the Marine Conventions, like HELCOM and OSPAR, that require a reduction by 50 % of emissions of nutrients from land-based sources. The level of emissions, however, is still high and shows that the pressure exerted on the environment from nutrients emitted from UWWT plants may still contribute to eutrophication problems.


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