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BMP testingFats, oils and animal by-products

Meat and meat waste — BMP: 2 studies, weighted mean 295 m³ CH₄/t VS

Meat and meat waste are protein- and fat-rich substrates with a high gas potential, but risky because of ammonia. They require hygienisation and compliance with the rules on by-products.

rating: neutralCH₄ ≈ 66 % (estimate)

Published Updated 3 min readFeedstockData Editorial Team

Photo Bi-frie (talk) / Wikimedia Commons, licence CC BY 3.0, source file; changes: cropping

Weighted mean
295m³ CH₄/t VS
Range
250–340m³ CH₄/t VS
Records
2studies
Publications
2sources
Temperatures
35 °C, 36 °Cof the test

Methane in biogas

High methane content · ≈ 6.6 kWh/m³ of biogas

estimate from the substrate type The collected studies contain no measurement. The interval follows from the approximate composition (protein-rich (process classification); fat-rich (process classification)) 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: high (79 m³ CH₄/t); process risk: fats, protein / nitrogen, foaming. Handling costs: ABP cat. 3.

Why? Rating factors

Potential per tonne +2

  • +2potential 79 m³ CH₄/t fresh matter (BMP 295 × DM 42.2 % × VS 63.1 %)

Process stability −2

  • −1fats: risk of accumulation of long-chain fatty acids (LCFA), flotation and overloading
  • −0.5protein / nitrogen: risk of ammonia inhibition at higher shares
  • −0.25foaming: tendency to form foam in the digester
  • −0.25acidification: rapid degradation / acidic pH, risk of VFA accumulation, needs buffering

Handling and costs −1

  • −1ABP cat. 3: pasteurisation at 70 °C / 60 min

Total points: −1 · 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 2 studies

Weighted mean Individual records

BMP curves: Meat and meat wasteCumulative methane production over time for 2 records and the weighted mean of 295 m³ CH₄/t VS. 2 of the curves are model curves (first-order kinetics).01002003004000510152025303540time [d]m³ CH₄/t VSAlkanok et al. (2014): 250 m³ CH₄/t VS (model curve)Kouas et al. (2017): 340 m³ CH₄/t VS (model curve)mean295

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 (295); 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
Alkanok et al. (2014) DOI25036 °C · mesophilicmeat wasteend point (model curve)
Kouas et al. (2017) DOI34035 °C · mesophilicbeefend point (model curve)
Weighted mean295arithmetic mean 295, SD 64

Typical composition

Dry matter (DM)
42.2% (range 42.2–42.2)
Volatile solids (VS)
63.1 % DM (range 63.1–63.1)

Median and range of the determinations reported in the publications behind this substrate's BMP records (read from: MY-D); dry matter: 1 determination, volatile solids: 1 determination. DM from a single determination – indicative value.

Sources: Alkanok et al. (2014).

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

  • protein-rich
  • fat-rich
  • nitrogen-rich
  • ABP cat. 3
  • tendency to foam
  • easily degradable
  • editorial classification

Advantages

  • Methane potential in the Substraty.pl BMP dataset: weighted mean 295.0 m³ CH₄/t VS (SD 63.6; 2 records, 2 sources).
  • Meat and meat waste have a high methane potential because they combine protein and fat (Hejnfelt and Angelidaki 2009).
  • Meat waste co-digested with slurry performs stably at a controlled dose (Hejnfelt and Angelidaki 2009; Pitk et al. 2014).

Drawbacks and risks

  • Double inhibition: ammonia from protein and LCFA from fat (Palatsi et al. 2011).
  • In a laboratory study at 7.5% (w/w) of sterilised slaughterhouse material the free NH3 concentration rose, and at 10% intense foaming and LCFA accumulation appeared (Pitk et al. 2013).
  • Putrefies quickly before use - requires cooling or rapid processing (Salminen and Rintala 2002).

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

Dosing

Indicative limit from the literatureup to 5% fresh mass of the feed[5]

Basis: share in the feed mixture (w/w). Pitkä et al. (2013) studied sterilised material (an ABP category 2 and 3 processing product, mainly fat and protein) in co-digestion with sewage sludge: up to 5% w/w (68% of the organic load) with no signs of inhibition, at 7.5% free NH3 increased and methane production fell, at 10% intense foaming and LCFA accumulation (experiment discontinued). Sterilised material is more concentrated than raw meat, so 5% is an indicative value; data from a single laboratory study.

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

Practical requirements

  • ABP cat. 3 (Art. 10 of Reg. 1069/2009; admitted to biogas plants by Art. 14): hygienisation before the digester in a mandatory unit: shredding to a maximum of 12 mm, temperature throughout the mass of at least 70 °C for at least 60 min without interruption (Reg. 142/2011, Annex V Ch. I Section 1 and Ch. III Section 1); the installation requires approval by the competent authority (Art. 24(1)(g) of Reg. 1069/2009).
  • Do not feed hygienised substrate into the digester hot (FNR 2010, Ch. 3: hygienisation).
  • Shred: shredding increases the surface available for degradation and speeds it up, but does not necessarily raise the final gas yield (FNR 2010, Ch. 3 “Triturado”).

Sources of the process data

  1. Pitk et al. (2014). Mesophilic co-digestion of dairy manure and lipid rich solid slaughterhouse wastes. Bioresour. Technol.
  2. Hejnfelt, Angelidaki (2009). Anaerobic digestion of slaughterhouse by-products. Biomass Bioenergy
  3. Rajagopal, Masse, Singh (2013). A critical review on inhibition of anaerobic digestion process by excess ammonia. Bioresour. Technol.
  4. Angelidaki, Ahring (1993). Thermophilic anaerobic digestion of livestock waste: the effect of ammonia. Appl. Microbiol. Biotechnol.
  5. Pitk et al. (2013). Co-digestion of sewage sludge and sterilized solid slaughterhouse waste: methane production efficiency and process limitations. Bioresour. Technol.
  6. Long et al. (2012). Anaerobic co-digestion of fat, oil, and grease (FOG): A review of gas production and process limitations. Process Saf. Environ. Prot.
  7. Palatsi et al. (2011). Anaerobic digestion of slaughterhouse waste: main process limitations and microbial community interactions. Bioresour. Technol.
  8. Salminen, Rintala (2002). Anaerobic digestion of organic solid poultry slaughterhouse waste - a review. Bioresour. Technol.
  9. Rozporządzenie (WE) nr 1069/2009 określające przepisy sanitarne dotyczące produktów ubocznych pochodzenia zwierzęcego (art. 9, 10, 12–14, 24)
  10. Rozporządzenie Komisji (UE) nr 142/2011 wykonujące rozporządzenie (WE) nr 1069/2009 (zał. IV rozdz. III, zał. V rozdz. I i III)
  11. FNR (2010). Guía sobre el Biogás – Desde la producción hasta el uso (hiszp. wydanie „Leitfaden Biogas”, GIZ 2013)

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

What it is and where it comes from

The category covers meat and meat waste: out-of-date products from supermarkets, processing residues and minced meat used in studies as a model material. The dataset contains several records: meat waste from a supermarket and minced beef. These are different materials, joined under one general designation, so the description is general in nature.

Properties relevant to digestion

Meat consists mainly of protein and fat, with a small amount of carbohydrates. Proteins decompose with the release of ammonia, which at high concentration inhibits methanogenesis, particularly under thermophilic conditions and at high pH. Fats have a high energy potential, but long-chain fatty acids can cause inhibition and foaming. For this reason meat is usually co-digested with material of lower nitrogen concentration, and the dose is introduced gradually. The material putrefies quickly, so it requires rapid processing or cooling.

How to read the spread of results

The records describe different things: a commercial waste (a mixture of different products, with bone, fat and packaging) and uniform minced meat. Differences in fat and bone content, the degree of comminution, sample preparation (freezing, homogenisation) and test conditions can give significant discrepancies. The substrate-to-inoculum ratio is very important here, because overloading the inoculum leads to the accumulation of acids and ammonia. The results of such a small sample must not be generalised to all meat waste.

In biogas plant practice

Meat waste and food waste of animal origin are animal by-products (ABP). Their use in a biogas plant requires compliance with EU and national rules: classification into a category, appropriate treatment (usually pasteurisation and size reduction for category 3 material), commercial documents and the relevant permits or registrations of the installation. The rules depend on the category of the material, so before acceptance they should be checked for your own biogas plant. Technically important are dosing in small portions, mixing with a liquid substrate, and monitoring the concentration of ammonia and volatile fatty acids. In the documentation it is worth distinguishing commercial waste from processing feedstock, because they differ in composition, cleanliness and category within the meaning of the rules, and in whether the supplier can guarantee a constant quality of the batch.

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 = 0.091 d−1 was assumed (no kinetic data for the group – the median of all available rate constants k (93 values) was used).

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. Alkanok, G.; Demirel, B.; Onay, T.T. (2014). Determination of biogas generation potential as a renewable energy source from supermarket wastes. Waste Management 34(1), 134–140. DOI: 10.1016/j.wasman.2013.09.015 DOI
  2. Kouas, M.; Torrijos, M.; Sousbie, P.; Steyer, J.P.; Sayadi, S.; Harmand, J. (2017). Robust assessment of both biochemical methane potential and degradation kinetics of solid residues in successive batches. Waste Management 70, 59–70. DOI: 10.1016/j.wasman.2017.09.001 DOI

All sources of the site: bibliography.

Other substrates in the group “Fats, oils and animal by-products”