WASTEWATER TREATMENT PLANTS - COMPLIANCE OF URBAN WASTEWATER TREATMENT SYSTEMS

Update date
Authors

Riccardo Boiocchi, Giancarlo De Gironimo, Massimo Peleggi, Silvana Salvati

Compliance monitoring allows for an understanding of the technological adaptation status of urban wastewater treatment systems for agglomerations greater than or equal to 2,000 PE (Population Equivalent). This is particularly useful for planning potential actions aimed at water protection.

Between 2022 and 2023, out of the 3,037 agglomerations analyzed, approximately 77% were found to be compliant, 13.8% non-compliant, 4.6% partially compliant, and 4.6% with data unavailable. A 100% compliance rate is recorded in Piedmont, Emilia-Romagna, Umbria, and the Autonomous Provinces of Trento and Bolzano.

Description

This response indicator provides information on the compliance of urban wastewater treatment systems with legal requirements for agglomerations with a biodegradable organic load of 2,000 PE or more. Compliance data for BOD5, COD, TSS, total nitrogen, and total phosphorus are declared on a plant-by-plant basis by comparing discharge parameter emission values with the emission limit values set by legislation, or by comparing the reduction percentages of these parameters with the minimum levels required by law.
Purpose

To verify the compliance of wastewater treatment plants with the requirements outlined in Legislative Decree No. 152 of April 3, 2006, which implemented Directive 91/271/EEC concerning urban wastewater treatment.
Policy relevance and utility for users
It is of national scope or applicable to environmental issues at the regional level but of national significance.
It is able to describe the trend without necessarily providing an evaluation of it.
It is simple and easy to interpret.
It is sensitive to changes occurring in the environment and/or human activities
It provides a representative overview of environmental conditions, environmental pressures, and societal responses.
Analytical soundness
Be based on international standards and international consensus about its validity;
Be theoretically well founded in technical and scientific terms
Presents reliability and validity of measurement and data collection methods
Temporal comparability
Spatial comparability
Measurability (data)
Adequately documented and of known quality
Updated at regular intervals in accordance with reliable procedures
An “adequate” spatial coverage
An “appropriate” temporal coverage
Main regulatory references and objectives
  • Directive 91/271/EEC
  • Legislative Decree 152/2006 (Part III)
DPSIR
Response
Indicator type
Descriptive (A)
References

https://cdr.eionet.europa.eu/help/UWWTD/UWWTD_613

 https://ec.europa.eu/environment/water/water-urbanwaste/info/pdf/terms.pdf
Limitations

The national overview could be more exhaustive if agglomerations with less than 2,000 Population Equivalent (PE) were included.
Further actions

Completion of information useful to the indicator.
Data source

Regions

Autonomous Provinces

ARPA/APPA (Regional Agencies and Autonomous Provinces for Environmental Protection)
Data collection frequency
Two year
Data availabilty

The data were acquired through the Urban Waste Water Treatment Directive 2024 (UWWTD 2024) questionnaire prepared by the European Commission to periodically check the state of implementation of the Directive on the national territory and made available on the SINTAI.
Spatial coverage

National, Regional
Time coverage

2022-2023
Core SET
SDGs Indicators
SDG goals
Goal 6: Clean water and sanitation
Processing methodology

Compliance with legal requirements was calculated for the wastewater treatment plant(s) associated with each agglomeration. For each degree of compliance was assigned a weight:

  • Compliant: 100% of the generated load is compliant (weight = 1).
  • Partially compliant: 75% of the generated load is compliant (weight = 0.75).
  • Non-compliant or data unavailable: (weight = 0).
Update frequency
Two-year
Data quality

The quality of information is deemed adequate for the requirements of current legislation. Data are collected and validated using uniform national procedures, enabling good temporal and spatial comparisons.

Status
Good
Trend
Steady
State assessment/description

The compliance data for wastewater treatment systems pertain to 2022–2023. The national compliance rate for wastewater treatment systems is 80.4% (Figure 1).
Trend assessment/description

The national compliance rate for wastewater treatment systems slightly decreased between 2020 (81.8%) and 2022–2023 (80.4%).
Comments

The compliance data for urban wastewater pertain to the period 2022–2023. Out of the 3,037 agglomerations analyzed:

  • 2,339 are compliant with the emission standards set by the directive.
  • 139 are partially compliant.
  • 419 are non-compliant.
  • 140 lack data for compliance assessment (Figure 3).

The compliance index exceeded 90% in 9 regions and in the Autonomous Provinces of Trento and Bolzano (100% in Emilia-Romagna, Piedmont, Umbria, and the autonomous provinces of Trento and Bolzano). In 6 regions, the compliance index ranged between 70% and 90%, whereas in Tuscany, Basilicata, Calabria, and Sicily, it was below 70%.

Even in 2022, the lowest compliance index was recorded in the region of Sicily (40%), which remained virtually unchanged compared to 2020 (40.2%) (Table 1, Figure 2).
Data
Data
Tabella 1 Conformità sistemi depurazione (nuova).xlsx (14.421 KB)
Headline

Table 1: Compliance with purification systems for agglomerations greater than or equal to 2,000 a.e. - regional detail (2022-2023)

Data source

ISPRA processing on ARPA/APPA and regional data (UWWTD 2024 questionnaire)
Headline

Figure 1: National compliance degree of sewage systems (2022-2023)

Data source

ISPRA processing on ARPA/APPA data and regional data (UWWTD 2024 questionnaire)
Headline

Figure 2: Grade of conformity of purification systems for agglomerations greater than or equal to 2,000 a.e. - regional detail (2022-2023)

Data source

ISPRA processing on ARPA/APPA data and regional data (UWWTD 2024 questionnaire)
Headline

Figure 3: Conformity of agglomerates greater than or equal to 2,000 a.e. related to purification systems (2022-2023)

Data source

ISPRA processing on ARPA/APPA data and regional data (UWWTD 2024 questionnaire)