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BMP testingMilk, whey and dairy waste

Dairy product waste (cheese, cream, ice cream) — BMP: 5 studies, weighted mean 504 m³ CH₄/t VS

Out-of-date cheeses, cream, curd cheese and ice cream are a fat-and-protein substrate of high potential, but with a risk of VFA and ammonia inhibition.

rating: neutralCH₄ ≈ 66 % (estimate)

Published Updated 3 min readFeedstockData Editorial Team

Illustration: FeedstockData (AI, Google Gemini)

Weighted mean
504m³ CH₄/t VS
Range
350–714m³ CH₄/t VS
Records
5studies
Publications
3sources
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: very high (198 m³ CH₄/t); process risk: fats, protein / nitrogen, salt / sodium. Handling costs: ABP cat. 3.

Why? Rating factors

Potential per tonne +3

  • +3potential 198 m³ CH₄/t fresh matter (BMP 504 × DM 41 % × VS 96 %)

Process stability −2.5

  • −1fats: risk of accumulation of long-chain fatty acids (LCFA), flotation and overloading
  • −0.5protein / nitrogen: risk of ammonia inhibition at higher shares
  • −0.5salt / sodium: inhibition at high 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 −0.5

  • −0.5ABP cat. 3: pasteurisation at 70 °C / 60 min (dairy products — derogations possible)

Total points: 0 · 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

BMP curves: Dairy product waste (cheese, cream, ice cream)Cumulative methane production over time for 5 records and the weighted mean of 504 m³ CH₄/t VS. 5 of the curves are model curves (first-order kinetics).0200400600800051015202530time [d]m³ CH₄/t VSAlkanok et al. (2014): 350 m³ CH₄/t VS (model curve)Labatut et al. (2011): 502 m³ CH₄/t VS (model curve)Luna-delRisco et al. (2011) · 1: 602 m³ CH₄/t VS (model curve)Luna-delRisco et al. (2011) · 2: 659 m³ CH₄/t VS (model curve)Luna-delRisco et al. (2011) · 3: 714 m³ CH₄/t VS (model curve)mean504

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 (504); 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) DOI35036 °C · mesophilicdairy product wasteend point (model curve)
Labatut et al. (2011) DOI50235 °C · mesophilicIce creamend point (model curve)
Luna-delRisco et al. (2011) · 160236 °C · mesophiliccottage cheeseend point (model curve)
Luna-delRisco et al. (2011) · 265936 °C · mesophiliccheeseend point (model curve)
Luna-delRisco et al. (2011) · 371436 °C · mesophilicsour creamend point (model curve)
Weighted mean504arithmetic mean 566, SD 144

Typical composition

Dry matter (DM)
41% (range 26.5–56.2)
Volatile solids (VS)
96 % DM (range 48.6–99.2)

Median and range of the determinations reported in the publications behind this substrate's BMP records (read from: MY-D); dry matter: 3 determinations, volatile solids: 5 determinations.

Sources: Alkanok et al. (2014); Labatut et al. (2011); Luna-delRisco et al. (2011).

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

  • fat-rich
  • protein-rich
  • easily degradable
  • ABP cat. 3
  • tendency to foam
  • saline
  • 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 503.5 m³ CH₄/t VS (SD 143.7; 5 records, 3 sources).
  • Readily available lactose and milk fat (Prazeres et al. 2012; Long et al. 2012).
  • Milk and dairy products in co-digestion with slurry are described as a substrate of high potential (Hagos et al. 2017).

Drawbacks and risks

  • Excess milk fat gives LCFA and foaming (Long et al. 2012).
  • Milk protein releases ammonia (Rajagopal et al. 2013).

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

Dosing

No source-based threshold. Start with a low share in a mix with slurry; shared limit for lipids.

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).
  • Milk, dairy products and colostrum may be used without hygienisation unless the authority considers there to be a risk of spreading a serious transmissible disease (Reg. 142/2011, Annex V, Chapter III, Section 1, point 1).
  • Do not feed hygienised substrate into the digester hot (FNR 2010, Ch. 3: hygienisation).
  • Remove foreign contaminants before dosing: material from biowaste may contain interfering substances, and the co-substrate should be free of them (FNR 2010, Ch. 3).

Sources of the process data

  1. Hagos et al. (2017). Anaerobic co-digestion process for biogas production: progress, challenges and perspectives. Renew. Sustain. Energy Rev.
  2. 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.
  3. Prazeres, Carvalho, Rivas (2012). Cheese whey management: A review. J. Environ. Manage.
  4. Rajagopal, Masse, Singh (2013). A critical review on inhibition of anaerobic digestion process by excess ammonia. Bioresour. Technol.
  5. Rozporządzenie (WE) nr 1069/2009 określające przepisy sanitarne dotyczące produktów ubocznych pochodzenia zwierzęcego (art. 9, 10, 12–14, 24)
  6. Rozporządzenie Komisji (UE) nr 142/2011 wykonujące rozporządzenie (WE) nr 1069/2009 (zał. IV rozdz. III, zał. V rozdz. I i III)
  7. 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

Out-of-date dairy products are cheeses, cream, curd cheese, yoghurts, ice cream and milk desserts, withdrawn from sale because the use-by date has been exceeded, packaging damaged or production errors made. They arise in supermarkets, distribution centres and dairy plants. The dataset contains samples of dairy waste from a supermarket and individual products: ice cream, curd cheese, cheese and cream. The material often reaches a biogas plant together with packaging, which has to be separated in a packaging separator.

Properties relevant to digestion

The composition depends on the product: cheeses and cream have a lot of fat, curd cheese a lot of protein, ice cream quite a lot of sugar and fat. Fats give a high methane potential, but in excess inhibit digestion through long-chain fatty acids and foaming. Protein releases ammonia. Fermented products are already acidified, and the large share of sugars in ice cream and desserts risks a rapid fall in pH. Salt in cheeses and preservatives (e.g. sorbates) can inhibit microorganisms, especially at larger doses.

How to read the spread of results

The spread is large because the entry covers products of radically different composition: from fatty cream to sweet ice cream. The result also depends on the proportions of fat, protein and sugar, the salt content, the presence of packaging, size reduction and the degree of spoilage. The substrate-to-inoculum ratio, the adaptation of the inoculum to fat and ammonia, the temperature and the length of the test also matter. Results for single products do not describe a mixture of supermarket waste.

In biogas plant practice

Such wastes are a valuable co-substrate at waste-treatment and agricultural biogas plants with suitable infrastructure, but dosing should be cautious, with monitoring of volatile acids, ammonia and foaming. Separation of packaging and size reduction are necessary. Dairy products are animal by-products within the meaning of Regulation (EC) No 1069/2009, so the plant must be approved for their processing and apply the required procedures, including hygienisation, unless the authority permits a derogation. It is worth confirming the details with the district veterinary officer.

For the operator it is also important that batches of such wastes are irregular and heterogeneous, so it is best to store them in a buffer tank and dose them as a constant, small share, rather than introducing large quantities at once.

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 = 0.270 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. 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. Labatut, R.A.; Angenent, L.T.; Scott, N.R. (2011). Biochemical methane potential and biodegradability of complex organic substrates. Bioresource Technology 102(3), 2255–2264. DOI: 10.1016/j.biortech.2010.10.035 DOI
  3. Luna-delRisco, M.; Normak, A.; Orupõld, K. (2011). Biochemical methane potential of different organic wastes and energy crops from Estonia. Agronomy Research 9(1–2), 331–342. https://www.semanticscholar.org/paper/25cf2d7bba4758136830a9a02caf3ecd997173bb source

All sources of the site: bibliography.

Other substrates in the group “Milk, whey and dairy waste”