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BMP testingMilk, whey and dairy waste

Whey — BMP: 19 studies, weighted mean 416 m³ CH₄/t VS

Whey, a by-product of cheesemaking, is a liquid substrate rich in lactose, which ferments quickly but readily acidifies the reactor and requires buffering.

rating: neutralCH₄ ≈ 53 % (estimate)

Published Updated 3 min readFeedstockData Editorial Team

Photo chuck b. / Wikimedia Commons, licence CC BY 2.0, source file; changes: cropping

Weighted mean
416m³ CH₄/t VS
Range
274–526m³ CH₄/t VS
Records
19studies
Publications
8sources
Temperatures
35 °C, 40 °Cof the test

Methane in biogas

Medium methane content · ≈ 5.3 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 1.8 % 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 (26 m³ CH₄/t); process risk: salt / sodium, acidification. No additional handling requirements.

Why? Rating factors

Potential per tonne +1

  • +1potential 26 m³ CH₄/t fresh matter (BMP 416 × DM 6.9 % × VS 91.8 %)

Process stability −1.5

  • −1salt / sodium: inhibition at high shares
  • −0.5acidification: rapid degradation / acidic pH, risk of VFA accumulation, needs buffering

Handling and costs 0

  • 0no factors

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: high · excluding market prices

Add to the co-digestion calculator CSV data

BMP curves from 19 studies

Weighted mean Individual records

BMP curves: WheyCumulative methane production over time for 19 records and the weighted mean of 416 m³ CH₄/t VS. 14 of the curves are model curves (first-order kinetics).0200400600051015202530time [d]m³ CH₄/t VSHafner et al. (2026) · lab. E18 · 1: 395 m³ CH₄/t VS (measurement)Hafner et al. (2026) · lab. E18 · 2: 424 m³ CH₄/t VS (measurement)Hafner et al. (2026) · lab. R05: 433 m³ CH₄/t VS (measurement)Hafner et al. (2026) · lab. E07: 464 m³ CH₄/t VS (measurement)Hafner et al. (2026) · lab. R03: 480 m³ CH₄/t VS (measurement)Fernández-Rodríguez et al. (2021): 274 m³ CH₄/t VS (model curve)Rico et al. (2014) · 1: 337 m³ CH₄/t VS (model curve)Rico et al. (2014) · 2: 351 m³ CH₄/t VS (model curve)Dinuccio et al. (2010): 501 m³ CH₄/t VS (model curve)Holliger et al. (2017): 526 m³ CH₄/t VS (model curve)Labatut et al. (2011): 424 m³ CH₄/t VS (model curve)Mainardis et al. (2019) · 1: 350 m³ CH₄/t VS (model curve)Mainardis et al. (2019) · 2: 353 m³ CH₄/t VS (model curve)Mainardis et al. (2019) · 3: 365 m³ CH₄/t VS (model curve)Mainardis et al. (2019) · 4: 380 m³ CH₄/t VS (model curve)Mainardis et al. (2019) · 5: 408 m³ CH₄/t VS (model curve)Mainardis et al. (2019) · 6: 430 m³ CH₄/t VS (model curve)Mainardis et al. (2019) · 7: 437 m³ CH₄/t VS (model curve)Llanos-Lizcano et al. (2024): 335 m³ CH₄/t VS (model curve)mean416

Dashed lines are a model curve (first-order kinetics, B(t) = B₀·(1 − e−kt)); the end point comes from the publication. Solid lines are measurements (5).

Cumulative methane production over the test [m³ CH₄/t VS]. The thick line is the weighted mean of all records (416); 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.

  • Show the remaining records in the legend (7)

Records and sources

Download CSV
SourceBMP
m³ CH₄/t VS		TemperatureSampleCurve
Hafner et al. (2026) · lab. E18 · 1 DOI395— · mesophilicWheymeasurement (31 pts)
Hafner et al. (2026) · lab. E18 · 2 DOI424— · mesophilicWheymeasurement (31 pts)
Hafner et al. (2026) · lab. R05 DOI433— · mesophilicWheymeasurement (31 pts)
Hafner et al. (2026) · lab. E07 DOI464— · mesophilicWheymeasurement (31 pts)
Hafner et al. (2026) · lab. R03 DOI480— · mesophilicWheymeasurement (31 pts)
Fernández-Rodríguez et al. (2021) DOI274—Cheese whey (100% whey)end point (model curve)
Rico et al. (2014) · 1 DOI33735 °C · mesophiliccheese whey (sample CW1)end point (model curve)
Rico et al. (2014) · 2 DOI35135 °C · mesophiliccheese whey (sample CW3)end point (model curve)
Dinuccio et al. (2010) DOI50140 °C · mesophilicWheyend point (model curve)
Holliger et al. (2017) DOI526—Wheyend point (model curve)
Labatut et al. (2011) DOI42435 °C · mesophilicCheese wheyend point (model curve)
Mainardis et al. (2019) · 1 DOI35035 °C · mesophilicFat CW4 (F4)end point (model curve)
Mainardis et al. (2019) · 2 DOI35335 °C · mesophilicSkimmed CW3 (S3)end point (model curve)
Mainardis et al. (2019) · 3 DOI36535 °C · mesophilicFat CW1 (F1)end point (model curve)
Mainardis et al. (2019) · 4 DOI38035 °C · mesophilicFat CW3 (F3)end point (model curve)
Mainardis et al. (2019) · 5 DOI40835 °C · mesophilicMozzarella CW1 (M1)end point (model curve)
Mainardis et al. (2019) · 6 DOI43035 °C · mesophilicFat CW2 (F2)end point (model curve)
Mainardis et al. (2019) · 7 DOI43735 °C · mesophilicFat CW5 (F5)end point (model curve)
Llanos-Lizcano et al. (2024) DOI335—Dairy industry waste (DIW, lacto serum), ISR 2end point (model curve)
Weighted mean416arithmetic mean 404, SD 64

Typical composition

Dry matter (DM)
6.9% (range 5.8–7.3)
Volatile solids (VS)
91.8 % DM (range 84–92.7)
Nitrogen
1.8 % DM

Median and range of the determinations reported in the publications behind this substrate's BMP records (read from: MY-D); dry matter: 8 determinations, volatile solids: 8 determinations.

Sources: Dinuccio et al. (2010); Labatut et al. (2011); Mainardis et al. (2019).

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

  • easily degradable
  • acidic
  • dilutes the feed (low DM)
  • saline
  • editorial classification

Advantages

  • Methane potential in the Substraty.pl BMP dataset: weighted mean 416.2 m³ CH₄/t VS (SD 64.0; 19 records, 8 sources).
  • Whey co-digested with dairy slurry - biogas optimisation was carried out (Kavacik and Topaloglu 2010; Hublin et al. 2012).
  • Low DM allows pumping and combining with solid substrates (Prazeres et al. 2012).

Drawbacks and risks

  • Lactose ferments quickly and acidifies; whey has low alkalinity (Prazeres et al. 2012).
  • High salt content in whey from salted cheeses (Prazeres et al. 2012).

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

Dosing

No source-based percentage. A mix with slurry in optimisation studies (Hublin et al. 2012); start with a low share.

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).

Sources of the process data

  1. Kavacik, Topaloglu (2010). Biogas production from co-digestion of a mixture of cheese whey and dairy manure. Biomass Bioenergy
  2. Hublin, Zokic, Zelic (2012). Optimization of biogas production from co-digestion of whey and cow manure. Biotechnol. Bioprocess Eng.
  3. Prazeres, Carvalho, Rivas (2012). Cheese whey management: A review. J. Environ. Manage.
  4. Rozporządzenie (WE) nr 1069/2009 określające przepisy sanitarne dotyczące produktów ubocznych pochodzenia zwierzęcego (art. 9, 10, 12–14, 24)
  5. Rozporządzenie Komisji (UE) nr 142/2011 wykonujące rozporządzenie (WE) nr 1069/2009 (zał. IV rozdz. III, zał. V rozdz. I i III)
  6. 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

Whey is the liquid fraction remaining after casein is precipitated during the production of cheeses and curd cheeses. It arises in a quantity of several litres per kilogram of cheese, so for a dairy it is a mass by-product. Part of the whey goes to processing (whey proteins, lactose, feed), and surpluses and acid whey are sometimes directed to biogas plants. In Poland the dairy industry is well developed, so whey is an available feedstock in regions with large plants. The dataset contains samples of sweet and acid whey and measured curves from an inter-laboratory comparison programme.

Properties relevant to digestion

The dry matter of whey is only a few per cent, and most of it is lactose, alongside whey proteins, trace amounts of fat and mineral salts. Lactose is hydrolysed and fermented very quickly, which causes a rapid formation of organic acids. Whey has a low pH and little buffering capacity, so at too high a dose the pH in the digester falls, inhibiting methanogenic archaea. On the other hand, the ammonia content is low, and the low C/N can be corrected by mixing with slurry. A high salt content (particularly in whey from salted cheeses) may be inhibitory.

How to read the spread of results

The results are distributed moderately widely. Sweet and acid whey differ in composition, and whey from different cheese dairies also differs in protein, residual fat and salt content. Freshness matters: old whey has partly fermented and lost its readily available sugars. The result depends on the inoculum (its buffering and adaptation), the substrate-to-inoculum ratio, temperature, test length and the method of conversion to VS. The measured curves come from many laboratories that used different protocols.

In biogas plant practice

Whey is a good co-substrate in a mixture with slurry or manure, which provide buffer and nitrogen. It is dosed evenly, in a small share, with monitoring of pH and volatile acids. Storage requires cooling or a short time, because it sours quickly. As a product of animal origin, it is an animal by-product (ABP) within the meaning of Regulation (EC) No 1069/2009; the plant must be approved for processing such materials and meet requirements concerning, among other things, hygienisation, unless the authority permits a derogation.

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. Hafner, S.D.; Leca, E.; Sambusiti, C.; Astals, S.; Azam, O.; Koch, K.; Liu, J.; Møller, H.B.; Nistor, M.; Olaya-Rincon, M.; Peyrelasse, C.; Ward, A.J.; Zennaro, B.; Monlau, F. (2026). Reliable biochemical methane potential testing: insights and recommendations from global interlaboratory study. Bioresource Technology 446, 134136. DOI: 10.1016/j.biortech.2026.134136 DOI
  2. Fernández-Rodríguez, M.; Puntano, N.; Mancilla-Leytón, J.; Borja, R. (2021). Batch mesophilic anaerobic co-digestion of spent goat batch mesophilic anaerobic co-digestion of spent goat straw bedding and goat cheese whey: Comparison with the mono-digestion of the two sole substrates. Journal of Environmental Management 280, 111733. DOI: 10.1016/j.jenvman.2020.111733 DOI
  3. Rico, C.; Diego, R.; Valcarce, A.; Rico, J.L. (2014). Biogas Production from Various Typical Organic Wastes Generated in the Region of Cantabria (Spain): Methane Yields and Co-Digestion Tests. Smart Grid and Renewable Energy 05(06), 128–136. DOI: 10.4236/sgre.2014.56012 DOI
  4. Dinuccio, E.; Balsari, P.; Gioelli, F.; Menardo, S. (2010). Evaluation of the biogas productivity potential of some Italian agro-industrial biomasses. Bioresource Technology 101(10), 3780–3783. DOI: 10.1016/j.biortech.2009.12.113 DOI
  5. Holliger, C.; Fruteau de Laclos, H.; Hack, G. (2017). Methane Production of Full-Scale Anaerobic Digestion Plants Calculated from Substrate’s Biomethane Potentials Compares Well with the One Measured On-Site. Frontiers in Energy Research 5, 12. DOI: 10.3389/fenrg.2017.00012 DOI
  6. 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
  7. Mainardis, M.; Flaibani, S.; Trigatti, M.; Goi, D. (2019). Techno-economic feasibility of anaerobic digestion of cheese whey in small Italian dairies and effect of ultrasound pre-treatment on methane yield. Journal of Environmental Management 246, 557–563. DOI: 10.1016/j.jenvman.2019.06.014 DOI
  8. Llanos-Lizcano, R.; Senila, L.; Modoi, O.C. (2024). Evaluation of Biochemical Methane Potential and Kinetics of Organic Waste Streams for Enhanced Biogas Production. Agronomy 14(11), 2546. DOI: 10.3390/agronomy14112546 DOI

All sources of the site: bibliography.

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