Urban waste water treatment

Indicator Assessment
Prod-ID: IND-15-en
Also known as: WAT 005
expired Created 26 Mar 2012 Published 31 Jan 2013 Last modified 21 Jan 2019
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This page was archived on 15 Dec 2017 with reason: Other (New version data-and-maps/indicators/urban-waste-water-treatment/urban-waste-water-treatment-assessment-4 was published)
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 over the last ten years. Latest values of population connected to wastewater treatment in the Southern countries are comparable to the values of Central and Northern countries, whereas the values of Eastern and South-Eastern Europe are still relatively low compared to 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 over the last ten years. Latest values of population connected to wastewater treatment in the Southern countries are comparable to the values of Central and Northern countries, whereas the values of Eastern and South-Eastern Europe are still relatively low compared to Central and Northern Europe.

How effective are policies aimed at improving urban waste water treatment at reducing discharges of nutrients and organic matter into surface waters?

Changes in wastewater treatment in regions of Europe between 1990 and 2012

Note: This figure illustrates the percentage population per European region connected to a waste water collection and treatment systems (UWWTPs) over the period 1980 to 2012. In addition, a breakdown by treatment type is portrayed. Numbers in brackets indicate number of countries in the aggregations.

Data source:
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Changes in wastewater treatment in Northern European countries between 1980s and 2009

Note: This figure illustrates the percentage population in Norhern European countries connected to a waste water collection and treatment systems (UWWTPs) over the period 1980 to 2009. In addition, a breakdown by treatment type is portrayed.

Data source:
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Changes in wastewater treatment in Central European countries between 1980s and 2009

Note: This figure illustrates the percentage population in Central European countries connected to a waste water collection and treatment systems (UWWTPs) over the period 1980 to 2009. In addition, a breakdown by treatment type is portrayed.

Data source:
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Changes in wastewater treatment in Southern European countries between 1980s and 2009

Note: This figure illustrates the percentage population in Southern European countries connected to a waste water collection and treatment systems (UWWTPs) over the period 1980 to 2009. In addition, a breakdown by treatment type is portrayed.

Data source:
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Changes in wastewater treatment in Eastern European countries between 1980s and 2009

Note: This figure illustrates the percentage population in Eastern European countries connected to a waste water collection and treatment systems (UWWTPs) over the period 1980 to 2009. In addition, a breakdown by treatment type is portrayed. Slovakia does not report wastewater treatment by treatment type.

Data source:

Data provenance info is missing.

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Changes in wastewater treatment in South- Eastern European countries between 1990s and 2009

Note: This figure illustrates the percentage population in South - Eastern European countries connected to a waste water collection and treatment systems (UWWTPs) over the period 1990 to 2009. In addition, a breakdown by treatment type is portrayed.

Data source:
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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. The connection of population to sewerage systems is dependent both on sanitation services provided and on demography (population density). A low percent of connection in agglomerations can be due to lack of financial resources (or priority) for providing the sanitation services or due to a high proportion of the population living outside agglomerations where individual sanitation systems is the most feasible solution.
Some independent appropriate systems (IAS) may exhibit same treatment efficiencies as larger urban waste water treatment plants.

Success indicators used in this assessment to measure the reduction of discharged loads of nutrients and organic matter from urban waste water treatment plants to European surface waters are:

  1. Percentage of national population connected to waste water treatment
  2. Percentage of national population connected to tertiary waste water treatment


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, and exceeds 90%. On the basis of data reported in 2010, about 67% of total population is connected to wastewater treatment in the countries of Eastern Europe. Average connection rate in South-East Europe (Turkey, Bulgaria and Romania) is about 40%. About a quarter of population in South Eastern countries is connected to collecting systems without treatment. For the remaining countries the value of percentage of population connected to collecting systems without treatment ranges from 1,5 to 5,6.

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 nearly half of the population in Southern and Eastern Europe receives tertiary treatment. This represents about 30% increase over last 10 years. In South-Eastern Europe the percentage of population connected to treatment plants with tertiary treatment is low (less that 9%), 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 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 Finland, 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 about 30% of the population is collected in collecting systems, but is not treated, whilst the majority of Icelandic population connected to waste water treatment (about 50%) receives primary treatment. 

Central Europe (Fig. 3): Central Europe has one of the with highest overall connection rates in Europe and in Germany, Denmark, Switzerland, Austria and the Netherlands the rate of population connected to tertiary treatment ranges between 77-96%.
Connection rate to tertiary treatment is about 60% in Belgium. On the other hand Belgium reported the highest percentage of population connected to collecting systems without treatment (17%) among the Central counties.
England and Wales and Scotland report connection rates to tertiary treatment of about 40%, whilst in Ireland the figure is considerably lower at 12%. Secondary treatment in Ireland, however, increased considerably (more than three times) between 2001 and 2005. Percentage of population connected to collecting systems without treatment (11%) is also relatively high in Ireland in comparison to other Central countries. Connection rate to tertiary treatment is relatively low also in Luxembourg ( 22%).

Southern Europe (Fig. 4): The overall rate of population connected to wastewater treatment ranges from 13% to 94% in the countries of Southern Europe, being highest in Italy(94%), Spain (92%) and Greece (88%) and lowest in Malta (13%).Tertiary treatment occurs most often in Italy, Greece with rates around 80%. Spain and France reported connection rate to tertiary treatment 51% and 42% respectively. In other countries of the region the percentage of population connected to tertiary treatment is lower than 20%. Moreover, Malta reported that more than 50% of population is connected to collecting systems without treatment.

Eastern Europe (Fig. 5): The overall rate of population connected to wastewater treatment ranges from 52 to 81% in countries of Eastern Europe. Percentage of national population connected to collecting systems without treatment does not exceed 10% in Eastern countries. About 60% of population in the Czech Republic and Estonia is connected to tertiary treatment. Poland and Lithuania reported connection rate to tertiary treatment about 50%. In Latvia, the rate of connection to tertiary treatment is lower, about 40% whilst in Hungary and Slovenia only about a quarter of the national population is connected to tertiary treatment. For Slovakia there is no detailed information on treatment type available in Joint Questionnaire, however according to the data reported under the UWWTD for the reference year 2008 about 16% of total load generated in agglomerations larger than 2000 p.e. receives tertiary treatment and 69,7% 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 29 to 46% in countries of South-Eastern Europe. Secondary or primary treatment prevails. Some tertiary treatment is applied in Turkey (12%).
About a quarter of population of Bulgaria and Turkey is connected to collecting systems without treatment. In Romania it is a bit less, 14%.

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

Type of waste water treatment in EU big cities (agglomerations of more than 150 000 p.e.) expressed as % of total generated load treated, situation on 31st December 2009/2010

Note: The pie-chart summarizes the type of treatment applied in the wastewater treatment plants of 586 big cities/big dischargers (250,2 mil. p.e.) reported in 2011 by the Member States and Norway. In total 640 big cities and big dischargers was reported, however complete data on waste water pathways was available only for 586.

Data source:
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Figure 7 summarizes the type of treatment applied in the wastewater treatment plants of 586 big cities/big dischargers with (250,2 mil. p.e.) reported in 2011 by the Member States. Five big cities reported no waste water treatment at all: 1 in Portugal , 1 in the United Kingdom and  3 in Italy.  Another seven had only primary treatment: 2 in Portugal, 1 in Spain, 2 in France and 2 in Romania. (deadline for compliance has expired in all above mentioned cases except for Romania)

Indicator specification and metadata

Indicator definition

The indicator on urban waste water treatment, WAT 005, 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 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 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

No methodology references available.

Uncertainties

Methodology uncertainty

The main uncertainties relate to data reported to Eurostat data.  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 includes data from agglomerations which are much smaller than 150 000 p.e. However, the impact of such errors on the final percentages is rather small.

 

 

Rationale uncertainty

Data gained 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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