WASTEWATER TREATMENT PLANTS - COMPLIANCE OF THE URBAN WASTEWATER SEWAGE SYSTEM

    Descrizione 1
    Update date
    Authors

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

    Abstract
    Immagine
    Abstract

    The presence or absence of a sewage network and the percentage of wastewater conveyed into collection systems indicate the degree of compliance with the requirements of the applicable regulations. In 2022-2023, the national compliance rate is 99.1%. Of the organic load, 95.7% is conveyed into the sewer system, 3.6% is treated through individual systems, while 0.7% is not connected.

    Description

    This is a response indicator that provides information about the coverage level of the sewer network within the agglomeration, and thus, the capacity to meet the need for wastewater collection. It is considered:

    • Compliant: the agglomeration has a sewer network with a coverage rate equal to or greater than 90%.
    • Partially compliant: the agglomeration has a sewer network with a coverage rate between 70% and 90%.
    • Non-compliant: the agglomeration has a coverage rate below 70%.
    Purpose

    To verify the compliance of sewage systems serving agglomerations across the national territory with the requirements established by the regulations.

    Policy relevance and utility for users
    It is of national scope or it is applicable to environmental issues at the regional level but of national relevance.
    It can describe the trend without necessarily evaluating it.
    It is simple and easy to interpret.
    It is sensitive to changes occurring in the environment and/or in human activities
    It provides a representative picture 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

    Legislative Decree No. 152 of April 3, 2006, titled "Environmental Regulations," as the transposition of Directive 91/271/EEC concerning urban wastewater treatment, sets a series of deadlines for the adjustment of collection and treatment systems serving agglomerations. The aim is to ensure complete territorial coverage of the sewage and treatment system and to upgrade existing facilities to meet the new qualitative standards set for water discharges and the environmental quality objectives for receiving water bodies established by the regulations.

    The European reference legislation also set December 31, 2005, as the final deadline for the technological upgrading of collection systems serving agglomerations with populations of 2,000 or more inhabitants (population equivalent - PE). The goal of Directive 91/271/EEC is to equip all urban agglomerations with sewer networks to convey wastewater to treatment plants, with technical requirements appropriate to the population size and the sensitivity of the receiving waters.

    DPSIR
    Response
    Indicator type
    Descriptive (A)
    References

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

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

    Limitations

    The national framework could be more comprehensive if agglomerations with fewer than 2,000 population equivalents were also considered.

    Further actions

    Completion of information useful to the indicator.

    Frequenza di rilevazione dei dati
    Biennale
    Fonte dei dati
    Agenzie Regionali e delle Province Autonome per la Protezione dell'Ambiente
    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

    Processing methodology

    The compliance of collection networks with the requirements established by the regulations was calculated. Each degree of compliance was assigned a weight (compliant = 1, partially compliant = 0.75, non-compliant and data not available = 0). For each agglomeration, the ratio between the "total collected load" and the "generated load," both expressed in population equivalents, was calculated. Compliance was expressed as a percentage of the total agglomerations.

    Update frequency
    Two-year
    Qualità dell'informazione

    The quality of information is deemed adequate to meet the requirements of the current legislation. Data are acquired and validated according to nationally homogeneous procedures, ensuring good temporal and spatial comparability.

    State
    Good
    Trend
    Positive
    State assessment/description

    The compliance of sewage systems related to agglomerations of 2,000 or more PE is 99.1% in 2022-2023 (Table 1).

    Trend assessment/description

    Compared to 2020, when compliance of sewage systems related to agglomerations of 2,000 or more population equivalents (PE) stood at 99.3%, no significant variations have been recorded.

    Comments

    Compliance of collection systems (sewage networks) with the requirements of the relevant legislation has reached 100% in 14 regions and the autonomous provinces of Trento and Bolzano. In Lazio, Campania, Basilicata, Calabria, and Sicily, compliance was 99.5%, 97.9%, 97.3%, 92.5%, and 98.7%, respectively (Table 1 – Figure 1). The national compliance rate of collection systems is 99.1%.

    Compliance was calculated by summing the percentage of organic load conveyed into the sewer system with that treated by "individual or appropriate systems," which, according to Directive 91/271/EEC, must represent a valid alternative to traditional urban wastewater collection and treatment systems when suitable environmental and economic conditions for installing usual systems are absent.

    Of the 3,037 agglomerations considered, 2,971 are compliant, 13 non-compliant, and 53 partially compliant (Table 1). Additionally, the percentage of organic load conveyed into the sewer system and that treated by individual or appropriate systems was calculated. Nationally, 95.7% of the organic load is conveyed into the sewer system (a total of 75,110,675 PE), 3.58% is treated in individual systems (2,811,932 PE), while 0.72% (563,188 PE) is not conveyed into a sewer system or individual systems (Table 2).

    At the regional level, the percentage of organic load conveyed into the sewer system was above 95% in 12 regions and the autonomous provinces of Trento and Bolzano, between 90% and 95% in 5 regions. Values below 90% were recorded in Basilicata (88.38%) and Sicily (82.94%) (Table 2 – Figure 2). Regarding the load conveyed to individual systems, in 10 regions and the autonomous provinces of Trento and Bolzano, it ranged between 0% and 1%; in 3 regions, it ranged between 1% and 5%; and in the remaining 6 regions, it exceeded 5%. The highest percentage of organic load conveyed into individual systems was recorded in Sicily, at 14.2%.

    Data
    Headline

    Table 1: Conformity of sewerage systems for agglomerations greater than or equal to 2,000 BC - regional detail (2022-2023)

    Data source

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

    Headline

    Table 2: Breakdown of the conveyed load in sewer mesh and in individual systems - regional detail (2022-2023)

    Data source

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

    Thumbnail
    Headline

    Figure 1: Grade of conformity of sewerage 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)

    Thumbnail
    Headline

    Figure 2: Collected organic load percentage - regional detail (2022-2023)

    Data source

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

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    Headline

    Figure 3: Total Overall Overall Combined Loading (2022-2023)

    Data source

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

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