QUANTITY OF WASTE SENT FOR COMPOSTING AND ANAEROBIC DIGESTION PROCESSES

    Descrizione 1
    Update date
    Authors

    Letteria Adella

    Abstract
    Immagine
    Abstract

    The indicator measures the amount of waste sent for biological treatment, specifically composting, integrated anaerobic/aerobic treatment, and anaerobic digestion. In 2022, the total amount of waste recovered through biological treatment processes (approximately 8.4 million tons) showed no significant variation, with a slight increase of 47,000 tons (+0.6%) compared to 2021. However, the share of organic waste, which decreased from about 6.8 million tons to approximately 6.7 million tons (79.6% of the total treated), saw a decline of around 132,000 tons (-1.9%), mainly due to a lower contribution of biodegradable waste from garden and park maintenance.

    Description

    The indicator measures the quantity of waste subjected to biological treatment as a whole and, in detail, the amounts sent for composting, integrated anaerobic/aerobic treatment, and anaerobic digestion. 

    Purpose

    To assess the effectiveness of policies promoting material recovery from waste.

    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 provides a representative picture of environmental conditions, environmental pressures, and societal responses
    It provides a basis for international comparisons.
    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
    Readily available or made available at a reasonable cost/benefit ratio
    An “adequate” spatial coverage
    An “appropriate” temporal coverage
    Main regulatory references and objectives

    EU Directive 2018/851 on waste

    EU Directive 2018/852 on packaging and packaging waste

    Legislative Decree 152/2006 and subsequent amendments

    Legislative Decree of April 29, 2010, No. 75 and subsequent amendments

    Ministerial Decree of February 5, 1998

    DPSIR
    Pressure
    Response
    Indicator type
    Descriptive (A)
    References

    Rapporto Rifiuti Urbani - EdiTion 2023

    Frequenza di rilevazione dei dati
    Annuale
    Fonte dei dati
    ISPRA
    Data availabilty

    I dati utilizzati derivano dalla banca dati delle dichiarazioni MUD e da appositi questionari inviati ad ARPA/APPA e gestori degli impianti e sono disponibili sul sito del catasto rifiuti (http://www.catasto-rifiuti.isprambiente.it).

    Spatial coverage

    NaTional, Regional

    Time coverage

    1997-2022

    Processing methodology

    The indicator measures the amount of waste sent for biological treatment, specifically composting, integrated anaerobic/aerobic treatment, and anaerobic digestion. Data on treatment facilities and waste quantities were collected through questionnaires sent to regional and provincial environmental protection agencies, regions, provinces, and regional and provincial waste observatories, as well as plant operators. The data were validated by cross-checking with the MUD database and through direct verification at individual plants.

    Update frequency
    Year
    Qualità dell'informazione

    The indicator addresses specific information needs (objective: sustainable waste management). Data are collected by ISPRA through the submission of dedicated questionnaires to the regional and provincial environmental protection agencies (ARPA/APPA), regional and provincial authorities, provincial waste observatories, and facility operators.

    The collected data are then subjected to a validation process, which includes cross-checking with the Environmental Declaration Form (MUD) database and, where necessary, targeted verifications at individual facilities. As a result, the indicator is considered accurate and comparable over time and across different geographical areas.

    State
    Good
    Trend
    Positive
    State assessment/description

    In recent years, the separate collection of organic waste has significantly increased, although some areas have yet to reach optimal levels. This trend has driven substantial development in the biological treatment sector, which has evolved through the adoption of innovative treatment technologies. In addition to traditional aerobic treatment systems aimed at producing soil amendments for agriculture, the national infrastructure has increasingly adopted integrated systems that combine aerobic treatment with anaerobic digestion. This integration enables both material and energy recovery while minimizing emissions and utilizing purified biogas for energy and biomethane production.

    In 2022, interest in this treatment method remained high, as evidenced by the closure of eight composting plants and the commissioning of nine new integrated treatment facilities (including four converted from aerobic treatment and one anaerobic digestion plant upgraded with an aerobic treatment section), along with one new anaerobic digestion plant. As a result, the sector’s total treatment capacity increased from approximately 11.2 million tons in 2021 to around 12 million tons. The national system consists of 358 facilities, specifically: 285 dedicated to aerobic treatment (composting); 51 for integrated anaerobic/aerobic treatment; 22 for anaerobic digestion.

    In 2022, the total amount of waste recovered through biological treatment processes (about 8.4 million tons) showed no significant variations, with a slight increase of 47,000 tons (+0.6%) compared to 2021. 

    Trend assessment/description

    Consistent with the trend in separate collection, the analysis of biological treatment data indicates a steady sectoral growth, both in terms of total waste treated (+92.9% between 2009 and 2022) and organic fraction recovery (+91% over the same period). The anaerobic digestion process, combined with aerobic treatment, has significantly contributed to progress in organic waste recovery in recent years. Between 2018 and 2022, integrated treatment grew by over 620,000 tons (+22.5%), whereas composting declined by 315,000 tons (-9.6%). Anaerobic digestion showed a slight increase (+3.7%).

    This data confirms that combining anaerobic and aerobic processes is crucial for increasing organic waste recovery. This approach allows for the production of high-quality soil amendments compliant with fertilizer regulations while simultaneously using biogas for electricity and heat generation or upgrading it into biomethane for transportation and other applications as a natural gas substitute. 

    Comments

    The analysis of data from the composting sector shows that, following the increase observed in 2021, the conversion of certain facilities from aerobic to integrated anaerobic/aerobic treatment, and the resulting diversion of organic waste flows (organic fraction + green waste) toward the latter treatment type, led to a decline in the quantities sent to composting during the 2021–2022 period. The total amount of waste treated via composting, amounting to 3.8 million tonnes, shows a reduction of over 197 thousand tonnes (-4.9%).

    The decrease is even more pronounced when considering the treatment of the organic fraction from separate collection, which amounted to approximately 3 million tonnes—down by 8.5%, or about 275 thousand tonnes. In particular, the aerobic treatment of the food waste fraction fell by around 141 thousand tonnes (-7.6%), while the green waste fraction recorded an even greater percentage reduction of 9.8%, equivalent to approximately 134 thousand tonnes (Table 1).

    In northern Italy—where integrated anaerobic/aerobic treatment plants are most concentrated and the majority of organic waste flows are diverted to this type of treatment—composting volumes dropped by over 228 thousand tonnes (-15.1%), reaching about 1.3 million tonnes (43.3% of the national total). A similar trend, though less pronounced, was observed in the central regions, where composted organic waste declined by approximately 67 thousand tonnes (-12.7%), with a total of about 458 thousand tonnes treated in 2022 (15.5% of the national total). Conversely, in the southern regions, over 1.2 million tonnes of separately collected waste (41.2% of the national total) were sent for composting, marking an increase of about 21 thousand tonnes (+1.7%) compared to 2021 (Table 1).

    The integrated anaerobic/aerobic treatment sector experienced further growth between 2021 and 2022. Total waste treated in this sector reached around 3.7 million tonnes, representing an increase of approximately 250 thousand tonnes (+7.3%) over the previous year. The portion consisting of organic waste from separate collection (about 3.4 million tonnes) increased by over 149 thousand tonnes (+4.6%) (Table 2).

    A detailed analysis by macro-geographical area shows that in 2022, sectoral growth was concentrated particularly in southern regions, which benefitted from upgrades to treatment infrastructure. In Apulia, the commissioning of four facilities—two newly constructed and two converted from aerobic systems—led to an increase of about 125 thousand tonnes of organic waste (+80.7%), bringing the total to approximately 280 thousand tonnes, or 8.3% of the national total.

    The central regions also saw the commissioning of a new facility converted from aerobic treatment and continued their positive trend, recording an increase of just over 5 thousand tonnes (+1.8%). The total organic waste treated in this area reached approximately 289 thousand tonnes, or 8.5% of the national total. In the northern regions, despite the addition of five new integrated treatment plants (including two converted from aerobic treatment), the trend remained relatively stable. Here, the quantity of organic waste from separate collection reached 2.8 million tonnes—an increase of 19 thousand tonnes (+0.7%)—accounting for 83.2% of the total treated nationwide (Table 2).

    Although anaerobic digestion processes a significantly lower volume of waste compared to integrated anaerobic/aerobic treatment, it still contributes to the recovery of organic fractions from separate collection. The total quantity of waste sent to anaerobic digestion amounted to over 884 thousand tonnes, showing a slight decrease compared to 2021 (-0.6%, or 5,290 tonnes). The portion consisting of organic waste from separate collection (over 315 thousand tonnes) also continued its negative trend, with a further reduction of more than 6 thousand tonnes (-1.9%) (Table 3).

    In northern Italy, where 19 out of the 22 operating anaerobic digestion plants are located, the trend was consistent with that observed during the 2020–2021 period. The quantity of organic waste processed in the North amounted to over 248 thousand tonnes (78.8% of the national total), reflecting a further decrease of around 18 thousand tonnes (-6.7%). The southern regions, which host two plants, recorded a slight decrease of 1 thousand tonnes (-1.9%). In the central regions, a new facility dedicated to treating organic fractions from separate collection came into operation in 2022, processing approximately 13 thousand tonnes—representing 4% of the national total (Table 3).

    Data
    Headline

    Table 1: Composting of waste, by region

    Data source

    ISPRA

    Data legend

    a Paper, cardboard, wood waste, waste from industrial sectors (agri-food, textile, paper, wood), and waste from aerobic and anaerobic waste treatment.

    Headline

    Table 2: Integrated anaerobic/aerobic treatment of waste, by region

    Data source

    ISPRA

    Headline

    Table 3: Anaerobic digestion of waste, by region

    Data source

    ISPRA

    Thumbnail
    Headline

    Figure 1: Quantities of waste subjected to biological treatment

    Data source

    ISPRA

    Thumbnail
    Headline

    Figure 2: Biological treatment of the organic fraction from separate collection, by type of management

    Data source

    ISPRA

    English