5.B.2 - Biological Treatment of Waste: Anaerobic Digestion at Biogas Facilities

Short description

Within NFR category 5.B.2, ammonia (NH3) emissions from the anaerobic digestion at biogas facilities are reported.

Category Code Method AD EF
5.B.2 CS NS CS

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Method(s) applied
D Default
T1 Tier 1 / Simple Methodology *
T2 Tier 2*
T3 Tier 3 / Detailed Methodology *
C CORINAIR
CS Country Specific
M Model
* as described in the EMEP/EEA Emission Inventory Guidebook - 2019, in category chapters.
(source for) Activity Data
NS National Statistics
RS Regional Statistics
IS International Statistics
PS Plant Specific
As Associations, business organisations
Q specific Questionnaires (or surveys)
M Model / Modelled
C Confidential
(source for) Emission Factors
D Default (EMEP Guidebook)
CS Country Specific
PS Plant Specific
M Model / Modelled
C Confidential

NOx NMVOC SO2 NH3 PM2.5 PM10 TSP BC CO Heavy Metals POPs
NA NA NA -/- NA NA NA NA NA NA NA

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L/- key source by Level only
-/T key source by Trend only
L/T key source by both Level and Trend
-/- no key source for this pollutant
IE emission of specific pollutant Included Elsewhere (i.e. in another category)
NE emission of specific pollutant Not Estimated (yet)
NA specific pollutant not emitted from this source or activity = Not Applicable

Separately collected organic waste (biowaste) from e.g. households, public garden and park service, food industry, restaurants, canteens and from agriculture can be treated in two different ways:
aerobically (composting) and anaerobically (biogas production).

The aim of the treatment is the production of digestate, leading to the recycling of nutrients and organic matter.

The produced digestate is used as fertilizer or soil improver in agriculture or horticulture and also in private gardening. In Germany, about 40% of the organic waste is treated in anaerobic digestion plants and ammonia (NH3) is an important emission to air.

Method

Emissions from anaerobic digestion at biogas facilities are not a key source and of minor priority.

Activity data

Official statistical data (Statistisches Bundesamt, Fachserie 19, Reihe 1: Abfallentsorgung (Waste management), Table 2.1; 1)) are used for the estimation. The data are published on a yearly basis with an exception for the actual year of reporting. The activity data for the actual year of reporting are obtained, initially, by carrying the relevant data from the previous year forward, in unchanged form. In the following year, when the actual activity data for the given year becomes available, they replace the data that were carried forward. This procedure has only a very small impact on the total emissions in the relevant current report year.

Emission factors

The emission factor used for calculating NH3 emissions is based on emission data from a research project 2). The NH3-EF is 274 g/t and used for the whole time series (which is starting in 1998).

Uncertainties

The AD from Statistisches Bundesamt have an uncertainty of ±2% whereas the uncertainty for the EF is -18/+920% (ibid.).

Recalculations

When preparing the current inventory data, statistical data are only available for the previous reporting year. The current reporting year must therefore be extrapolated on the basis of the previous year. The result of this approach is revised by the correct data in the following year. For this reason, annual recalculations are required for the previous year.

Table 1: Revised biowaste activity data, in [kt]

2021
current submission 6,503
previous submission 5,532


Table 2: Accordingly revised NH3 emissions, in [t]

2021
current submission 1,782
previous submission 1,516

For pollutant-specific information on recalculated emission estimates for Base Year and for the current year, please see the recalculation tables following chapter 8.1 - Recalculations.

Planned improvements

Currently no improvements are planned.



1) Statistisches Bundesamt, Fachserie FS 19, Reihe 1: Abfallentsorgung; Wiesbaden; URL: https://www.destatis.de/DE/Publikationen/Thematisch/UmweltstatistischeErhebungen/Abfallwirtschaft/Abfallentsorgung.html
2) Carsten Cuhls, Birte Mähl, Joachim Clemens; gewitra Ingenieurgesellschaft für Wissenstransfer mbH: Ermittlung der Emissionssituation bei der Verwertung von Bioabfällen; https://www.umweltbundesamt.de/publikationen/ermittlung-der-emissionssituation-bei-der; im Auftrag des Umweltbundesamtes, April 2015