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BMP testingAnimal excreta (slurry, manure, poultry litter)

Rabbit manure — BMP: 2 studies, weighted mean 218 m³ CH₄/t VS

Rabbit excreta (manure and slurry) are a little-studied substrate; the dataset contains several records from several studies, so the data are indicative.

rating: neutralCH₄ ≈ 54 % (estimate)

Published Updated 3 min readFeedstockData Editorial Team

Photo Parkywiki / Wikimedia Commons, licence CC BY-SA 3.0, source file; changes: cropping

Weighted mean
218m³ CH₄/t VS
Range
173–264m³ CH₄/t VS
Records
2studies
Publications
2sources
Temperatures
37 °C, 38 °Cof the test

Methane in biogas

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 1.7 % DM × 6.25)) and the yields of compound groups according to FNR.

How we calculate it and what the zones mean

Rating for biogas plants

neutral — editorial rating for biogas plantsNo clear advantages — worth charging a fee for accepting it

Potential per tonne of fresh matter: moderate (35 m³ CH₄/t); process risk: protein / nitrogen. Handling costs: fibres, floating layer.

Why? Rating factors

Potential per tonne +1

  • +1potential 35 m³ CH₄/t fresh matter (BMP 218 × DM 25.5 % × VS 62.7 %)

Process stability −1

  • −1protein / nitrogen: risk of ammonia inhibition at higher shares

Handling and costs −0.5

  • −0.5fibres, floating layer — shredding and intensive mixing

Total points: −0.5 · thresholds: ≥ 2.5 very good, ≥ 1 good, below — neutral; negative with cumulative process risk.

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

Add to the co-digestion calculator CSV data

BMP curves from 2 studies

Weighted mean Individual records

BMP curves: Rabbit manureCumulative methane production over time for 2 records and the weighted mean of 218 m³ CH₄/t VS. 2 of the curves are model curves (first-order kinetics).0100200300051015202530time [d]m³ CH₄/t VSCu et al. (2014): 173 m³ CH₄/t VS (model curve)Lallement et al. (2023): 264 m³ CH₄/t VS (model curve)mean218

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 (218); 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
SourceBMP
m³ CH₄/t VS		TemperatureSampleCurve
Cu et al. (2014) DOI17337 °C · mesophilicrabbit manureend point (model curve)
Lallement et al. (2023) DOI26438 °C · mesophilicrabbit slurryend point (model curve)
Weighted mean218arithmetic mean 218, SD 64

Typical composition

Dry matter (DM)
25.5% (range 18.4–32.7)
Volatile solids (VS)
62.7 % DM (range 39.5–86)
Nitrogen
1.7 % DM
C/N ratio
24.5

Median and range of the determinations reported in the publications behind this substrate's BMP records (read from: MY-D); dry matter: 2 determinations, volatile solids: 2 determinations. C/N was calculated as the ratio of C and N content (% DM) from the same source.

Sources: Cu et al. (2014); Lallement et al. (2023).

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

  • fibrous
  • nitrogen-rich
  • variable composition
  • 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 218.3 m³ CH₄/t VS (SD 64.3; 2 records, 2 sources).
  • Shredded rabbit droppings provide microflora and buffering.

Drawbacks and risks

  • N-rich urine may increase ammonia; little data - indicative value.
  • At a high share, free ammonia inhibits methanogenesis, especially at higher temperature and pH (Rajagopal et al. 2013).

Dosing

No source threshold.

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

  1. Rajagopal, Masse, Singh (2013). A critical review on inhibition of anaerobic digestion process by excess ammonia. Bioresour. Technol.
  2. Rozporządzenie (WE) nr 1069/2009 określające przepisy sanitarne dotyczące produktów ubocznych pochodzenia zwierzęcego (art. 9, 10, 12–14, 24)
  3. Rozporządzenie Komisji (UE) nr 142/2011 wykonujące rozporządzenie (WE) nr 1069/2009 (zał. IV rozdz. III, zał. V rozdz. I i III)

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

What it is and where it comes from

Rabbit excreta arise on farms breeding rabbits for meat, fur and laboratory use. They can occur as solid manure with bedding, as a suspension from cage washing, or as slurry, depending on the housing system. The dataset contains several samples from different studies, one of which is described as rabbit slurry. The scale of production in Poland is small, so this material is not an important biogas plant substrate.

Properties relevant to digestion

Rabbits are herbivores, and their excreta contain undigested fibre, so, like the manure of other herbivores, they consist mainly of cellulose, hemicellulose and lignin. The nitrogen content is moderate, but rabbit urine is rich in nitrogen and can increase the ammonia concentration. Dry matter depends on the system: slurry is dilute, and manure with bedding has a higher content. The material contains microflora useful in co-digestion, and comminution of the bedding improves flow.

How to read the spread of results

The records differ in the form of the material (manure or slurry), which in itself explains part of the spread. It is also affected by the feed (hay, pellets), the share of urine, the bedding, the storage time, the temperature, the inoculum and the substrate-to-inoculum ratio. With a small number of records from several studies, variability of the material cannot be distinguished from differences between laboratories.

In biogas plant practice

Rabbit excreta can supplement a manure mixture on the farm where they arise. Because of the small scale of production they are not a stand-alone substrate. They require comminution of the bedding and monitoring of ammonium nitrogen. As a natural fertiliser they are 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 the excreta of other farm animals, rabbit material is drier and more fibrous than slurry, and less so than cattle manure. Because of the small number of records the result should be treated as indicative only, and a test on your own batch carried out before practical use.

It is also worth checking what bedding is used on the particular farm, because sawdust lowers the result more markedly than straw.

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

  1. Cu, T.T.T.; Nguyen, T.X.; Triolo, J.M.; Pedersen, L.; Le, V.D.; Le, P.D.; Sommer, S.G. (2014). Biogas Production from Vietnamese Animal Manure, Plant Residues and Organic Waste: Influence of Biomass Composition on Methane Yield. Asian-Australasian Journal of Animal Sciences 28(2), 280–289. DOI: 10.5713/ajas.14.0312 DOI
  2. Lallement, A.; Peyrelasse, C.; Lagnet, C.; Barakat, A.; Schraauwers, B.; Maunas, S.; Monlau, F. (2023). A Detailed Database of the Chemical Properties and Methane Potential of Biomasses Covering a Large Range of Common Agricultural Biogas Plant Feedstocks. Waste 1(1), 195–227. DOI: 10.3390/waste1010014 DOI

All sources of the site: bibliography.

Other substrates in the group “Animal excreta (slurry, manure, poultry litter)”