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Urban waste water treatment in Europe

Indicator Assessment
Prod-ID: IND-15-en
Also known as: WAT 005
Created 11 Oct 2010 Published 20 Dec 2010 Last modified 21 Jan 2019
15 min read
This is an old version, kept for reference only.

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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 policies to improve urban waste water treatment at reducing discharges of nutrients and organic matter into surface waters in Europe?

Changes in wastewater treatment in regions of Europe between 1990 and 2007

Note: This figure illustrates the percentage population per European region connected to an Urban Wastewater Treatment Plant over the period 1990 to 2007. In addition, a breakdown by treatment type is portrayed.

Data source:

EEA-ETC/WTR (CSI024) based on data reported to OECD/EUROSTAT Joint Questionnaire 2008. Data are available at Eurostat data tables.

Downloads and more info

Changes in wastewater treatment in Northern European countries between 1980s and 2006

Note: Percentage of population connected to different types of wastewater treatment.

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 Western European countries between 1980s and 2007

Note: Percentage of population connected to different types of wastewater treatment.

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 Southern European countries between 1980s and 2007

Note: Percentage of population connected to different types of wastewater treatment.

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 Eastern European countries between 1980s and 2007

Note: Percentage of population connected to different types of wastewater treatment.

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 South-eastern European countries between 1980s and 2007

Note: Percentage of population connected to different types of wastewater treatment.

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 and national legislation for non-EU countries is to protect surface waters from the adverse effects of wastewater discharges. This is achieved through the requirement for collection and treatment of wastewater in all settlements (agglomerations) and areas of economic activity with a population equivalent (p.e.) larger than 2000. As a rule, the UWWT Directive provides for biological treatment of waste water  (secondary treatment), which would otherwise deplete oxygen levels in receiving waters, threatening aquatic ecosystems. In catchments with particularly sensitive waters (sensitive areas), such as those suffering from eutrophication, more stringent tertiary waste water treatment measures are required, in order to substantially reduce nutrient pollution (nitrogen and phosphorus) from waste water.


Percentage of national population connected to waste water treatment.
About 80 % of the population is connected to waste water treatment in Northern and Southern European countries. The connection rate in Central European countries is even higher, at 90 %. On the basis of data reported in 2006-2007, about 65 % of total population is connected to wastewater treatment in the countries of Eastern Europe. Average connection in  South-Eastern Europe (Turkey, Bulgaria and Romania) is about 40 % .
Percentage of national population connected to tertiary waste water treatment
More than 70 % of the population in Northern and Central Europe is connected to a wastewater treatment plant that implements tertiary treatment, substantially removing nutrients and organic matter. Wastewater generated by more than 40% of the population in Southern and Eastern Europe receives tertiary treatment. This represents a 20% increase over last five years. In South-Eastern Europe the percentage of population connected to treatment plants with tertiary treatment is low (8,5%), with 21% of the population of the region being connected to secondary treatment.

Timetable for the compliance with the UWWT Directive varies for EU15  and for new EU Member States (EU12). For Austria, Belgium, Denmark, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, Netherlands, Portugal, Spain, Sweden and UK the latest date to fully comply with the Directive was 31/12/2005. For the new Member States in Central and Eastern Europe and in the Mediterranean, staged transitional periods have been set in a clear and legally binding way within the Accession Treaties; In principle these transitional periods do not exceed the year 2015; only in Romania, smaller agglomerations (with less than 10,000 p.e.) have to comply with the Directive by the end of 2018.

Specific regional assessment
Northern Europe (Fig. 2):  The connection rate is around 80 % in Norway, Sweden and Finland and, in the case of the latter two, treatment is entirely at a tertiary level. In Norway, however, about a quarter of those connected receive primary treatment only. In Iceland waste water from half of the population is not treated at all whilst the other half receives primary treatment. 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 (Fig. 3): Central Europe has the highest overall connection rates in Europe. In Germany, Denmark, Switzerland, Austria and the Netherlands the rate of population connected to tertiary treatment range between 77-96 %.  England and Wales and Scotland report connection rates to tertiary treatment are about 45%, whilst in Ireland the figure is considerably lower at 12 %., Secondary treatment in Ireland, however, increased considerably (more than tripled) between 2001 and 2005. Connection rate to tertiary treatment is relatively low in Belgium and Luxembourg 36% and 22%, respectively.

Southern Europe (Fig. 4): The overall rate of population connected to wastewater treatment ranges from 13% to 85 % in the countries of Southern Europe, being highest in Greece (85%) and Spain (81%)  and lowest in Malta (13%).Tertiary treatment occurs most often in Greece and Spain with rates of 78% and 42% respectively. In other countries of the region the percentage of population connected to tertiary treatment is lower than 20%.

Eastern Europe (Fig. 5): The overall rate of population connected to wastewater treatment ranges from 50 to 75 % in countries of Eastern Europe. About 60 % of population in the Czech Republic and Estonia is connected to tertiary treatment. In Poland, Latvia and Lithuania, the rate of connection to tertiary treatment is lower, about 40%; while Hungary and Slovenia report the lowest connection rate to tertiary treatment in the Eastern Europe region 20% and 13%, respectively. For Slovakia there is no detailed information on treatment type available in Joint Questionnaire, however according to the data reported in 2007 under the Urban Wastewater Treatment Directive, 23% of total load generated in agglomerations larger than 2000 p.e.receives tertiary treatment and 63 % of total load is treated in plants equipped with secondary treatment.

South-Eastern Europe (Fig. 6).; The rate of population connected to waste water treatment plants ranges from 28 to 42 % in countries of South-Eastern Europe. Secondary or primary treatment prevails. Some tertiary treatment is applied in Turkey (10%).

What levels of urban waste water treatment are applied in 'big cities' in the EU?

Number of EU agglomerations of more than 150 000 p.e. by treatment level, situation on 31st December 2005/2006

Note: The pie-chart summarizes the type of treatment applied in the wastewater treatment plants of 297 big cities/big dischargers (129,3 mil. p.e.) reported in 2007 by 18 Member States (AT, BE, CY, DK, EE, FI, FR, DE, HU, LV, LT, LX, NL, PT, RO, SK, SI, SE)

Data source:

EEA-ETC/WTR based on country data reported via the Urban Wastewater Treatment Directive

Downloads and more info

The lastest 2009 EU Commissions Urban Waste Water Treatment (UWWT) Directive implementation report  can be found here DGENV 2009, 5th synthesis report on UWWTD implementation .

Figure 7 summarizes the type of treatment applied in the wastewater treatment plants of 297 big cities/big dischargers (129,3 mil. p.e.) reported in 2007 by 18 Member States (AT, BE, CY, DK, EE, FI, FR, DE, HU, LV, LT, LX, NL, PT, RO, SK, SI, SE).  86 % of the total generated load produced in big cities (111,9 mil.p.e.) is discharged in sensitive areas out of which , 76 % of the total generated load receives more stringent – tertiary - treatment. Remaining load of 14% (17,4 mil p.e.) produced in big cities/big dischargers is discharged in normal or less sensitive areas. In ‘normal’ and ‘less sensitive’ areas 38 % (6,6 mil p.e.) of the generated big city load receives secondary treatment, and   46 % (7,98 mil.p.e.) receives more stringent tertiary treatment, at a standard, therefore, higher than that required by the UWWT Directive.
Out of big cities reported in 2007, five had no waste water treatment at all: one in Portugal and four in Romania. Another four had only primary treatment: two in Portugal and one  in France and Romania. 

Further information can be found in the WISE section on Urban Waste Water Treatment Directive and WISE Viewer maps Urban Waste Water

Indicator specification and metadata

Indicator definition

The indicator on urban waste water treatment, WAT005, collects data on the percentage of the population connected to sewage collection systems, as well as on the prevalence of primary, secondary and tertiary urban waste water treatment plants.

The amount of urban waste water treated from 'big cities' is expressed as population equivalents (p.e.).

The indicator illustrates:

  1. urban waste water collection and treatment in Europe in 2017;
  2. the development of more stringent (tertiary) urban waste water treatment practice;
  3. the level of urban waste water treatment in 'big cities (agglomerations of > 150 000 p.e.) in the EU.

Units

The percentages of the population connected to primary, secondary and tertiary urban waste water treatment facilities (Figures 1 and 2).

The percentage of population equivalent (p.e.) was used for “big city” treatment (Figure 3).


Policy context and targets

Context description

The main objective of the Urban Waste Water Treatment Directive (91/271/EEC) (UWWTD), and equivalent national legislation for non-EU countries, is to protect surface waters from the adverse effects of waste water discharges. The UWWTD prescribes the level of treatment required before discharge to surface waters. It requires Member States to provide all urban settlements (called 'agglomerations' in the UWWTD) of more than 2 000 p.e. with collecting systems. Primary (mechanical) and secondary (i.e. biological) treatments must be provided for all agglomerations of more than 2 000 p.e. that discharge into fresh waters. Special requirements, with intermediate deadlines depending on the sensitivity of the receiving waters, are placed on urban settlements of more than 10 000 p.e., with various size classes. The performance of the treatment is assessed using several determinands (biochemical oxygen demand (BOD) and chemical oxygen demand (COD); plus total nitrogen and total phosphorus in the case of more stringent treatment).

For urban settlements smaller than those described above and equipped with a collecting system, the treatment must be 'appropriate', meaning that the discharge must allow the receiving waters to meet the relevant quality standards.

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 the substances listed in Annex VIII, from urban, industrial, agricultural and other installations and activities, based, inter alia, on information gathered, for instance, under Articles 15 and 17 of the UWWTD. Based on the substances listed in Annex VIII WFD, the following are important for this indicator:

  • substances that have an unfavourable influence on oxygen balance (and can be measured using parameters such as BOD, COD, etc.);
  • materials in suspension;
  • substances that 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 of reaching good ecological and good chemical status of surface waters, as required by the WFD.

Collecting and treating waste water has required huge investment across Europe in recent decades. The kinds of new challenges facing urban waste water treatment, such as climate change, resource efficiency and improved environmental protection, are set out in the EEA briefing Urban waste water treatment for 21st century challenges.

Further information on emissions from industry to water, including to urban waste water treatment plants, is available in Industrial waste water treatment - pressures on Europe's environment.

Targets

The UWWT Directive (91/271/EEC) 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. For the newer Member States (i.e. the EU-13), staged transition periods were set within the Accession Treaties which, in principle, did not extend beyond 2015. However, in Romania, smaller agglomerations (with less than 10 000 p.e.) should have complied with the directive by the end of 2018, and Croatia has different transition periods, from 2018 to 2023.

Under the directive, EU-15 Member States were required to provide all urban settlements of more than 2 000 p.e. with collecting systems and all waste waters collected had to be provided with appropriate treatment by 2005. Secondary treatment (i.e. biological treatment) must be provided for all urban settlements 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.


The achievements resulting from the UWWTD should be seen as an integral part of achieving good status for all waters under the WFD. 

 

        

Related policy documents

Methodology

Methodology for indicator calculation

The indicator is based on data from Eurostat, which show the percentage of the population connected to each treatment type. Compared with previous versions of the indicator, Figure 1 now shows the treatment level in EEA member and cooperating countries in 2017, rather than grouping countries according to region.

A p.e. of 1 is equivalent to an organic biodegradable load having a 5-day BOD of 60 g per day.

Tertiary treatment is known in the UWWT Directive as 'treatment more stringent than secondary' and includes the application of secondary treatment.

'Big cities' is a term used in the UWWT Directive for cities of at least 150 000 p.e. or agglomerations responsible for large waste water discharges. Countries themselves identify their 'big cities'.

Methodology for gap filling

Gap filling was undertaken on the basis that once an urban waste water infrastructure had been put in place, it was likely to be used in subsequent years. Therefore, any gaps were filled with data from the most recent year reported, e.g. 2016 data carried forward to 2017. This approach was used for up to 5 years of gap filling, i.e. 2012 data could be carried forward to up to 2017.

 

Methodology references

  • Eurostat Water statistics on national level (env_nwat) Yearly data on freshwater resources, water abstraction and use, connection rates of resident population to wastewater treatment, sewage sludge production and disposal, generation and discharge of wastewater collected biennially by means of the OECD/Eurostat Joint Questionnaire - Inland Waters. Data aggregation: national territories.

Uncertainties

Methodology uncertainty

The main uncertainties relate to data reported to Eurostat. In 2005, treatment for 24 % of the population was 'unknown', which fell to 15 % in 2017.  The second area of uncertainty relates to numbers of inhabitants, as these do not necessarily align with reported population data, though error here is generally small.

The 'EU-27' value is strongly influenced by the situation in Member States with large populations (France, Germany, Italy and Spain).  

At country level, the population figure and the generated p.e. load are not usually the same, as there can be other sources of organic pollution, such as food industry and temporal changes in population owing e.g. to tourism.

Data sets uncertainty

Data reported to Eurostat sometimes provide an incomplete picture of inhabitants connected to waste water treatment (e.g. the percentage of the population connected to urban waste water systems is given, but the percentage for which the waste water is collected without treatment is missing).

'Big cities' data sometimes include data from agglomerations that are much smaller than 150 000 p.e. However, the impact of such errors on the final percentages is rather small.

 

 

Rationale uncertainty

Data from the UWWT Directive focuses on the performance of the treatment plant and of the agglomeration. However, urban waste water treatment systems could also include sewer networks with storm water overflows and storage, which are complex and therefore 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 or 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 the definitions of different classes of treatment (classes based on performance or design capacity and tertiary treatment for nitrogen, phosphorus or organic matter) that, in turn, lead to differences in the level of purification attributed by the countries to the different classes. These differences emphasise the problem of using types of treatment plant as a proxy for the level of purification.

 

 

Data sources

Metadata

Topics:

information.png Tags:
, ,
DPSIR: Response
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)
Indicator codes
  • WAT 005
Temporal coverage:

Dates

Frequency of updates

Updates are scheduled every 3 years

EEA Contact Info

Caroline Whalley
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