BMP testingAnimal excreta (slurry, manure, poultry litter)

Pig manure (solid) — BMP: 5 studies, weighted mean 293 m³ CH₄/t VS

Pig manure and solid pig excreta (sows, piglets) are a material with a higher dry matter content than slurry, rich in nitrogen, with a moderate methane potential.

rating: good CH₄ ≈ 54 % (estimate)

Published 1 September 2024Updated 29 October 20263 min readFeedstockData Editorial Team

Illustration: FeedstockData (AI, Google Gemini)

Weighted mean: 293m³ CH₄/t VS
Range: 178–444m³ CH₄/t VS
Records: 5studies
Publications: 4sources
Temperatures: 36 °C, 37 °C, 38 °Cof the test

Methane in biogas

≈52–55% CH₄

Medium methane content · ≈ 5.4 kWh/m³ of biogas

estimate from the substrate type The collected studies contain no measurement. The interval follows from the approximate composition (protein from total nitrogen (N 2 % DM × 6.25; in manure part of the N is ammonium nitrogen)) and the yields of compound groups according to FNR.

How we calculate it and what the zones mean

Rating for biogas plants

good — editorial rating for biogas plantsStable, usually accepted without a fee

Potential per tonne of fresh matter: high (72 m³ CH₄/t); process risk: protein / nitrogen, inhibitors, sulphur. No additional handling requirements.

Why? Rating factors

Potential per tonne +2

+2potential 72 m³ CH₄/t fresh matter (BMP 293 × DM 31 % × VS 79.4 %)

Process stability −0.25

−1protein / nitrogen: risk of ammonia inhibition at higher shares
−0.5inhibitors: natural or residues (e.g. limonene, polyphenols, antibiotics, metals)
−0.25sulphur: H₂S in the biogas (toxicity to bacteria, corrosion, desulphurisation)
+1.5high alkalinity — stabilises the pH of the mixture

Handling and costs 0

0no factors

Total points: 1.75 · thresholds: ≥ 2.5 very good, ≥ 1 good, below — neutral; negative with cumulative process risk.

Editorial rating per the methodology · confidence of the rating: medium · excluding market prices

Add to the co-digestion calculator CSV data

BMP curves from 5 studies

Weighted mean Individual records

Dashed lines are a model curve (first-order kinetics, B(t) = B₀·(1 − e^−kt)); the end point comes from the publication. All curves are model curves.

Cumulative methane production over the test [m³ CH₄/t VS]. The thick line is the weighted mean of all records (293); dots mark the end values given in the publications. Point at the chart to read values; click a legend item to hide or show a record.

Records and sources

Download CSV

Source	BMP m³ CH₄/t VS	Temperature	Sample	Curve
Cu et al. (2014) · 1 DOI	178	37 °C · mesophilic	sow manure	end point (model curve)
Cu et al. (2014) · 2 DOI	444	37 °C · mesophilic	piglet manure	end point (model curve)
Kafle i Chen (2016) DOI	322	36 °C · mesophilic	swine manure	end point (model curve)
Lallement et al. (2023) DOI	218	38 °C · mesophilic	Pig manure	end point (model curve)
Li et al. (2013) DOI	322	37 °C · mesophilic	Swine Manure	end point (model curve)
Weighted mean	293	arithmetic mean 297, SD 104

Typical composition

Dry matter (DM): 31% (range 19.4–37.2)
Volatile solids (VS): 79.4 % DM (range 72.4–85)
Nitrogen: 2 % DM
C/N ratio: 19.4

Median and range of the determinations reported in the publications behind this substrate's BMP records (read from: MY-D); dry matter: 5 determinations, volatile solids: 4 determinations. C/N was calculated as the ratio of C and N content (% DM) from the same source.

Sources: Cu et al. (2014); Kafle et al. (2016); Lallement et al. (2023); Li et al. (2013).

The composition of the raw material varies between batches — for plant calculations use an analysis of your own sample. The calculator inserts typical values automatically.

Process properties

nitrogen-rich
high alkalinity (buffer)
high dry matter
sulphur-rich
contains inhibitors
editorial classification

Low confidence: the description is based on general characteristics of the substrate group, not on studies of this material. Treat it as a hint to be verified.

Advantages

Methane potential in the Substraty.pl BMP dataset: weighted mean 293.1 m³ CH₄/t VS (SD 104.0; 5 records, 4 sources).
Higher DM than slurry, N and buffer (Hansen et al. 1998).

Drawbacks and risks

Ammonia risk, especially under thermophilic conditions (Hansen et al. 1998; Angelidaki and Ahring 1993).
Residues of medicines and Cu/Zn from feed may inhibit (Chen et al. 2008).

Co-digestion — what to combine it with, what to watch out for

combines well
substrates: carbon-rich — e.g. Wheat straw, Maize silage (whole crop), Cereal straw (unspecified), Willow (short rotation), Cardboard and paperboard
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Dosing

No source-based threshold; monitor NH4-N. Start with a medium share.

Introduce gradually, starting with a small dose and monitoring the process (e.g. FOS/TAC, pH, gas composition).

Practical requirements

ABP cat. 2 (Art. 9 of Reg. 1069/2009): manure, slurry and digestive tract content may be digested without prior sterilisation if the authority does not recognise a risk of spreading a serious transmissible disease (Art. 13(e)(ii)); in that case a minimum of 70 °C for a minimum of 60 min applies (Reg. 142/2011, Annex V Ch. III Section 1), and where they are the only material of animal origin in the installation, the authority may approve other requirements (Section 2 point 3).

Sources of the process data

The co-digestion calculator will assess a specific mixture containing this substrate.

What it is and where it comes from

Solid pig excreta arise in bedded piggeries and after slurry separation. The dataset includes samples of sow and piglet excreta and unspecified "swine manure" and "pig manure" from several studies. In Poland most pigs are kept in litter-free systems, so this material makes up a smaller part of pig excreta than slurry, but is sometimes available from bedded farms and after separation.

Properties relevant to digestion

Pig excreta contain less fibre than cattle manure, but more nitrogen, which increases the ammonia risk, especially at higher temperature and at high doses. The dry matter content is higher than in slurry, particularly with added bedding. The material is well buffered. Feed additives such as copper and zinc, and residues of veterinary medicines, can affect the microflora. During storage, losses of nitrogen and organic matter occur, depending on temperature and aeration.

How to read the spread of results

The spread results from the category of animals (sows, piglets and fattening pigs have different feed and different excreta), the type and amount of bedding, the storage time and the way the sample was prepared. Test parameters also have an effect: temperature, inoculum (its adaptation to ammonia), substrate-to-inoculum ratio and duration. The dataset includes few records from several sources, so the values also reflect differences between laboratories, and the range is not a complete measure of uncertainty.

In biogas plant practice

Solid pig excreta work well in co-digestion with materials of a higher C/N ratio, which mitigate ammonia. Ammonium nitrogen and pH must be monitored. Comminution and even dosing improve stability. Pig excreta are a natural fertiliser, subject to the fertilisation rules, and in the context of ABP they are category 2 material, which may be used in a biogas plant under the conditions set out in EU and national regulations.

For comparison with pig slurry, the solid material is easier to transport, and the concentration of dry matter allows the volume of the feed to be reduced. In return it requires comminution and even mixing in the digester. These characteristics must be taken into account when choosing the dosing system.

Methodology in brief

BMP is the amount of methane obtained from volatile solids (VS) in a batch test, given in m³ CH₄ per tonne of VS (numerically the same as NmL CH₄/g VS in the publications) and converted to normal conditions (0 °C, 101.325 kPa). The weighted mean gives each publication a total weight of 1, split equally between its results for the substrate — a paper testing twenty varieties does not outweigh a paper with a single sample. In inter-laboratory programmes the unit is the laboratory (total weight 1), and within it the weight of a test grows with the number of bottles (replicates). Results after pretreatment (e.g. thermal, chemical, enzymatic) are shown separately and are not included in the mean.

Solid lines are curves measured in the tests. Where a publication gives only the final result, we draw a first-order kinetic model, B(t) = B₀·(1 − e^−kt): only the end point comes from the publication, and the shape of the curve serves purely as visualisation — do not read the production on a particular day from it. For this substrate k = 0.393 d⁻¹ was assumed (median of rate constants k reported in the sources and/or fitted to the mean measured curves).

The statistics describe the spread of published results — a descriptive compilation, not a meta-analysis or a guarantee of plant yield.

Full methodology and correction policy

Bibliography

All sources of the site: bibliography.