Urban waste water treatment

Indicator Assessment
Prod-ID: IND-15-en
Also known as: CSI 024 , WAT 005
expired Created 29 Nov 2007 Published 29 Jan 2009 Last modified 05 Oct 2017
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Wastewater treatment in all parts of Europe has improved during the last 15-20 years. The percentage of the population connected to wastewater treatment in the southern, south-eastern and eastern Europe has increased during last ten years, but is still relative low compared to the central and northern Europe.

Key messages

Wastewater treatment in all parts of Europe has improved during the last 15-20 years. The percentage of the population connected to wastewater treatment in the southern, south-eastern and eastern Europe has increased during last ten years, but is still relative low compared to the central and northern Europe.

How effective are existing policies in reducing discharges of nutrients and organic matter into surface waters?

Changes in wastewater treatment in regions of Europe between 1990 and 2005

Note: Only countries with data from (almost) all periods were included, the numbers of countries are given in parentheses

Data source:

EEA-ETC/WTR based on country data reported to OECD/EUROSTAT Joint Questionnaire. Data are available at Eurostat data tables.

Downloads and more info

Changes in wastewater treatment in northern countries of Europe between 1980s and 2005

Note: N/A

Data source:

EEA-ETC/WTR based on country data reported to OECD/EUROSTAT Joint Questionnaire. Data are available at Eurostat data tables.

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Changes in Changes in wastewater treatment in countries of Europe between 1980s and 2005 (Western)

Note: N/A

Data source:

EEA-ETC/WTR based on country data reported to OECD/EUROSTAT Joint Questionnaire. Data are available at Eurostat data tables.

Downloads and more info

Changes in wastewater treatment in countries of Europe between 1980s and 2005 (Southern)

Note: N/A

Data source:

EEA-ETC/WTR based on country data reported to OECD/EUROSTAT Joint Questionnaire. Data are available at Eurostat data tables.

Downloads and more info

Changes in wastewater treatment in countries of Europe between 1980s and 2005 (East)

Note: N/A

Data source:

EEA-ETC/WTR based on country data reported to OECD/EUROSTAT Joint Questionnaire. Data are available at Eurostat data tables.

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Changes in wastewater treatment in countries of Europe between 1995 and 2005 (South-Eastern)

Note: N/A

Data source:

EEA-ETC/WTR based on country data reported to OECD/EUROSTAT Joint Questionnaire. Data are available at Eurostat data tables.

Downloads and more info

The main objective of the Urban Waste Water Treatment (UWWT) Directive is to protect the environment from the adverse effects of urban waste water discharges and discharges from certain industrial sectors and the measures concerns the collection, treatment and discharge of most of the waste water.

As a rule, the UWWT Directive provides for biological waste water treatment (secondary treatment), and thus a drastic reduction of the biodegradable pollution in waste water - which otherwise would severely impact on oxygen balance and ecosystems of our waters. In the catchments of particularly sensitive waters (sensitive areas), such as those suffering from eutrophication, more stringent treatment measures are required, to additionally eliminate nutrient pollution (nitrogen and phosphorus) from waste water (tertiary treatment).

 

The success indicators used in this assessment to measure the reduction in discharges of nutrients and organic matter from urban waste water to European surface waters are:

1. Percentage of population connected to waste water treatment.

2. Percentage of waste water given tertiary treatment.

 

1. Percentage of population connected to waste water treatment (Fig. 1 and the individual countries in Fig. 2-6). In northern and also in southern European countries more than 80 % of the population is connected to waste water treatment. In sparcely populated countries with a relative high proportion of the population living in scattered dwellings these dwelling are not connected to collecting systems and normally served by individual waste water treatment (e.g. septic tanks). In central Europe more than 90 % is connected. In eastern Europe only 50 % is connected (last data are from 2002, so this percentage may be higher now), whereas in south-eastern Europe (Turkey, Bulgaria and Romania) there is only 35 % that are connected to waste water treatment plants.

 

2. Percentage of waste water given tertiary treatment (yellow color on Fig. 1 to 6). Most of the population in the northern countries is connected to waste water treatment plants with the highest levels of treatment (tertiary), which efficiently removes nutrients (phosphorus or nitrogen or both) and organic matter. More than half of the waste water in central European countries is subject to tertiary treatment. In southern and eastern Europe only 20 % get tertiary treatment. Around half of the wastewater in southern European countries and 25 % in eastern Europe receive only secondary treatment. In south-eastern Europe the level of tertiary treatment is minor (< 5 %), whereas 20 % is subject to secondary treatment.

 

What is the level of urban waste water treatment in large cities in the EU?

Number of EU15 agglomerations of more than 150 000 p.e. by treatment level, situation on 1st January 2003.

Note: N/A

Data source:

DGENV 2007

Downloads and more info

The lastest from 2007 EU Commissions Urban Waste Water Treatment (UWWT) Directive implementation report  can be found on http://ec.europa.eu/environment/water/water-framework/implrep2007/index_en.htm. According to this report waste water treatment in 349 out of the 571 big cities of Europe complied with the treatment requirements of the UWWT Directive without any need for updating the treatment. 122 of the 571 big cities with population equivalent more than 150 000 did not have a sufficient standard of treatment on 1st of January 2003 to meet the objectives of the UWWT Directive. 17 had no treatment at all. No information is available for four cities. These big cities account for 55% of the total waste water pollution load of organic matter covered by the 1998 and 2000 UWWT Directive deadlines (i.e. of > 470 mil. p.e.). 

 

Further information can be found in the WISE section on Urban Waste Water Treatment Directive http://www.eea.europa.eu/themes/water/water-pollution/prevention-strategies/urban-waste-water-treatment-directive.

 

Specific assessments of waste water treatment in different countries:

Northern Europe: Most of the waste water (80%) in Finland, Sweden and Norway receives tertiary treatment (Fig. 2), while in Iceland the waste water from half of the population is not treated at all and the other half only receive primary treatment. The trends in the rate of national population connected to the UWWTPs are affected by changes in the ratio of rural/urban population as well as by increasing use of separate individual treatment plants in rural areas.

 

Central Europe: In Switzerland, Germany, Denmark, Austria and the Netherlands most of the population is connected to the tertiary treatment (Fig. 3). In Ireland more than 30 % has no treatment at all and more than 40 % of waste water receives only primary treatment. In Belgium more than 60 % of the population had no treatment at all at the time of the last reporting (1998), but national state of the environment reports indicate marked improvement in waste water treatment over the last decade.

 

Southern Europe: The best situation is in Spain where more than 90% of population is connected to treatment systems (fig. 4). The worst situation is in Malta, where almost 90 % of population has no treatment of their waste water at all. In France 80 % is connected, whereas the percentage connected to waste water treatment in Italy, Greece and Portugal is higher than 60 %,  higher than  50 % and ca. 40 %, respectively. Tertiary treatment is minor in this region in general with maximum 20 % of the total waste water (Italy, France and Spain), and less than 10 % in Greece and Portugal

 

Eastern Europe:  More than 65 % of the population in the Czech Republic, Estonia, Latvia and Lithuania is connected to the waste water treatment, and roughly half of the waste water connected to treatment systems is given tertiary treatment (fig. 5). For Poland and Hungary around 60 % of the population is connected to waste water treatment systems. In Poland about half of the connected wastewater are given tertiary treatment, whereas in Hungary only 10 % gets tertiary treatment. The worst situation is in Slovenia, where almost 70 % of the population is not connected to waste water treatment systems. For Slovakia there is no detailed information on treatment type available.

 

South-Eastern Europe: In south eastern European countries (Turkey, Bulgaria, Romania) only around 40% of the population is connected to the waste water treatment, with most of the connected waste water receiving only secondary or primary treatment (fig. 6). Only in Turkey there is a small proportion of the waste water that receives tertiary treatment.

 

Indicator specification and metadata

Indicator definition

The indicator on waste water treatment CSI 024 is defined as the percentage of the population connected to sewage collection systems as well as primary, secondary and tertiary waste water treatment plants. The amount of the waste water is expressed as population equivalents (p.e.). The indicator illustrates:

  1. development of waste water collection and treatment in Europe since the 1970s;

  2. development of more stringent waste water treatment;

  3. level of waste water treatment in large cities (agglomerations >150 000 p.e.) in the EU.

 

Units

Percentages of population connected to primary, secondary and tertiary wastewater treatment.


Policy context and targets

Context description

The Urban Waste Water Treatment (UWWT) Directive (91/271/EEC) prescribes the level of treatment required before discharge to surface water. It requires Member States to provide all agglomerations of more than 2 000 population equivalents (p.e.) with collecting systems. Primary (mechanical) and secondary treatment (i.e. biological treatment) must be provided for all agglomerations of more than 2 000 p.e. discharging into fresh waters. Special requirements with intermediate deadlines depending on the sensitivity of the receiving waters are placed on agglomerations of more than 10 000 p.e. with various size classes of agglomerations. The performance of the treatment is assessed using five different determinands (Biochemical oxygen demand - BOD, Chemical oxygen demand - COD, Total suspended solids - TSS, Total nitrogen - Ntot and Total phosphorus - Ptot).

For agglomerations smaller than described above and those equipped with a collecting system, the treatment must be “appropriate”, meaning that the discharge allows the receiving waters to meet the relevant quality objectives.

The UWWTD, adopted in 1991, is also a basic measure under the Water Framework Directive (WFD). The WFD requires the estimation and identification of significant point and diffuse source pollution, in particular by substances listed in Annex VIII, from urban, industrial, agricultural and other installations and activities, based, inter alia, on information gathered i.a. under Articles 15 and 17 UWWTD. From the substances listed in Annex VIII WFD, the following are important for CSI 024:

  • substances which have an unfavourable influence on the oxygen balance (and can be measured using parameters such as BOD, COD, etc.),
  • materials in suspension, and
  • substances which contribute to eutrophication (in particular, nitrates and phosphates).

Member States should thus take the necessary steps to collect these data. Reducing pollutants stemming from waste water is one of the key challenges for reaching good ecological and good chemical status of surface waters, as required by the WFD.

Targets

The Urban Waste Water Treatment Directive aims to protect the environment from the adverse effects of urban waste water discharges. It prescribes the level of treatment required before discharge and should have been fully implemented in the EU-15 countries by 2005 and in the ten new Member States by 2008 - 2015. The directive requires Member States to provide all agglomerations of more than 2 000 population equivalent (p.e.) with collecting systems and all waste waters collected to be provided with appropriate treatment by 2005. Secondary treatment (i.e. biological treatment) must be provided for all agglomerations of more than 2 000 p.e. that discharge into fresh waters, while more advanced treatment (tertiary treatment) is required for discharges into sensitive areas. To help minimise pollution from various point sources, the Integrated Pollution Prevention and Control directive, which came into force 1996, has a set of common rules on permitting for industrial installations.

The achievements through the UWWTD and the IPPC directive have to be seen as an integrated part of objectives under the Water Framework Directive (WFD) which aim at a good chemical and biological status for all waters by 2015.

Related policy documents

  • COM(2004) 248 final
    Implementation of Council Directive 91/271/EEC of 21 May 1991 concerning urban waste water treatment, as amended by Commission Directive 98/15/EC of 27 February 1998
  • Council Directive (91/271/EEC) of 21 May 1991
    Council Directive of 21 May 1991 concerning urban waste water treatment (91/271/EEC)
  • Urban wastewater treatment summary report
    Summary report on: the identification of sensitive areas by the Member States; the measures implemented by the Member States with the view to the deadline of 31 December 1998; wastewater treatment in major cities; verification of the identification of sensitive areas by the Commission.

Methodology

Methodology for indicator calculation

The CSI 024 is based on data from Eurostat, which is then aggregated into groups of countries. Percentages connected to each treatment type, weighted by total population in each country were used from Eurostat tables. Compared to previous versions of the indicator, the time steps have been regularised and the number of countries reported in each region in Figure 1 has been kept constant across the time period.

 

Methodology for gap filling

The most recent year reported was used for gap filling e.g. 2013 data used for 2014. This approach used for up to 9 years gap filling.

 

Methodology references

No methodology references available.

Uncertainties

Methodology uncertainty

For the assessment shown in Figure 1, countries have been grouped to show the relative contribution on a larger statistical basis. So as to provide a complete and comparable dataset over the time period, some countries have been omitted from the European overview.

Regional results are biased towards countries with the largest population (e.g. Turkey constitutes about 70 % of the inhabitants in the whole South-eastern European region).

 

Data sets uncertainty

Eurostat data sometimes provides an incomplete picture of connected or treated inhabitants (e.g. the percentage of population connected to waste water systems is given, but the percentage where the waste water is collected without treatment is missing).

Slovakia reported much of its waste water treatment as “not specified” which leads to a probable under-estimate of the amount of treatment applied in that country.

 

 

Rationale uncertainty

Data gained from the UWWT Directive focuses on the performance of the treatment plant alone. However, waste water treatment systems could also include sewer networks with storm water overflows and storage which are complex and  overall performance is difficult to assess. In addition to the treatments covered by the UWWT Directive, there are other possible treatments, mostly industrial, but also independent treatments of smaller settlements outside urban agglomerations not included in UWWT Directive reporting. Compliance with the levels defined in the directive therefore does not guarantee that there is no pollution due to urban waste water.

In addition, urban waste water treatment (primary, secondary and tertiary, as described above) is the main waste water treatment used across the EEA area, but there are other possible treatments classified as “Other Waste Water Treatment”, which are mostly industrial or independent treatments. Furthermore, there are differences in how countries have interpreted and implemented the Directive leading to differences in the data reported. In particular, there are variations in the definitions of different classes of treatment between countries (classes based on performance or on design capacity and tertiary treatment for N, P or organic matter) that in turn lead to differences in the level of purification attributed by the countries to the classes. These differences emphasise the problem of using types of treatment plant as a proxy for the level of purification.

 

 

Data sources

Generic metadata

Topics:

information.png Tags:
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DPSIR: Response
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)

Contacts and ownership

EEA Contact Info

Caroline Whalley

EEA Management Plan

2010 (note: EEA internal system)

Dates

Frequency of updates

Updates are scheduled every 2 years
European Environment Agency (EEA)
Kongens Nytorv 6
1050 Copenhagen K
Denmark
Phone: +45 3336 7100