Accurate measurement of biochemical methane potential (BMP) is essential for biogas research and practice. This site provides information and documents (mostly free and open-access) aimed at standardizing BMP measurement. 

To get started with accurate BMP measurement, select Methods. If you are new to BMP, start with Basics.

The biomethane potential or biochemical methane potential (BMP) of a specific substrate defines the maximum amount of methane that can be produced by anaerobic digestion. The definition refers to the existing state of the sample as it is analysed or applied in fermentation processes. Thus, substrate pre-treatment or disintegration processes prior to analysis can change the BMP. The BMP can be measured in validated BMP tests carried out in a laboratory, or estimated using stoichiometric calculations (including degradability and substrate share for microbial growth and maintenance).

The actual methane yield that is obtained from a digester represents the recovered fraction of the BMP under practical process and operating conditions. Thus, the yield is dependent on numerous factors, including retention time, organic loading rate, degradation kinetics, mixing, inhibitory effects or nutrient (including trace element) deficiency. By definition, the actual methane yield cannot exceed the BMP of a substrate. A higher specific methane yield during continuous operation compared to the BMP is a clear indication of improper conditions in the BMP test (such as an unsuitable inoculum) or measurement error in continuous experiments.

The BMP is a key parameter for substrate characterisation and efficiency evaluation of anaerobic digestion plants. It is crucial for assessing quality and monetary value of different substrate types, and enables reliable process balancing.

BMP is typically measured in anaerobic batch tests in a laboratory setup (BMP test), but can also be estimated from principles of microbial stoichiometry, in conjunction with detailed substrate characterization and assumptions on substrate degradability and microbial growth. The fundamental principle of a BMP test is rather simple: A sample of the investigated substrate is digested with an active and well-functioning inoculum in bottles incubated at an appropriate temperature. Additionally, blank samples, only containing inoculum, are incubated as well. Assuming no synergistic/antagonistic effects, the resulting methane production of the substrate can be determined by subtracting methane production of the blank (inoculum) from the substrate sample (substrate + inoculum). The final value of cumulative methane production after test termination is defined as the experimental BMP of the substrate.

As summarized in a recent publication: BMP tests are a powerful and useful tool in AD research and practice. They can be applied for the experimental determination of the BMP of pure or mixed substrates. Based on stoichiometric calculations, the anaerobic biodegradability can be estimated by dividing the obtained BMP by a theoretical value. Kinetic parameters achieved from BMP tests allow for a qualitative evaluation of process kinetics. However, kinetic parameters estimated in batch operation cannot be applied for detailed description of continuous processes. While acute toxicity of an inhibitor present in the substrate or mutually added can be detected in BMP tests, this is not possible for chronic toxicity. As in contrast to continuously operator systems, the substrate in a BMP test is only added once, and owing to the typically high share of inoculum present in the assay, synergistic or antagonistic occurring in co-digestion BMP tests can be different from those occurring in continuous processes. BMP tests cannot be utilized to assess long-term effects of nutrients or trace elements availability due to constant feeding. Similarly, the methane yield, process stability, rheology or kinetics in a continuously operated system cannot be elucidated by BMP tests.

Koch, K., Hafner, S.D., Weinrich, S., Astals, S. and Holliger, C. (2020): Power and limitations of biochemical methane potential (BMP) tests. In: Frontiers in Energy Research 8, 63. https://doi.org/10.3389/fenrg.2020.00063 

Many labs have long-term experience with BMP tests, and numerous methods are available. However, details about individual test methodology is often incomplete in papers and report, which hinders evaluation of experimental results. Inter-laboratory comparisons have shown low reproducibility among labs, which is related to a lack of standardization in both laboratory methods and calculations (processing of raw measurements). The Standard BMP Methods website was developed to help standardize measurements methods and calculations for more accurate and reproducible BMP determination. For detailed recommendations, select the Methods link. For background information, select Literature.

• The use of an accepted protocol and measurement method
• Application of standardized equations for calculating BMP from raw laboratory data
• Evaluation of results using accepted validation criteria, and elimination of results that are likely to be inaccurate

Below you can find practical documents that describe all of these components. All documents listed below are free and open-access, and should be cited in reports or papers in lieu of a detailed description of methods (see "Citing these documents" below or each individual document for citation information). Each has an associated approval list of researchers, showing that it describes widely accepted methods (to add your name, please contact us). For papers and other information related to these documents, see the Literature and Tools and Links pages.

All BMP tests should follow the guidelines given in the document below, which represents the consensus view of more than 50 biogas researchers. It includes both required components for any BMP protocol, as well as validation criteria. Use of validation criteria to eliminate results that are likely inaccurate is important for improving inter-laboratory reproducibility. Any test that does not meet the criteria listed in this document should be repeated. For a short summary of the validation criteria see document 101 instead.

• BMP requirements (document 100) EN | DE | ES | FR | IT | PT

BMP calculations are relatively simple, but the level of detail given in peer-reviewed papers is often insufficient. Calculation of BMP should follow the steps given in the following document.

• BMP calculation (document 200) EN

Determination of the standardized volume of methane produced requires method-specific calculations. The following open-source documents provide detailed equations for four approaches, including two common variations for each.

• Volumetric (document 201) EN
• Manometric (document 202) EN
• Gravimetric (document 203) EN
• Gas density (document 204) EN | ES

BMP can be measured using a variety of approaches. Commercial automated systems – typically volumetric – require the least labor and deliver the highest temporal resolution, but the initial cost is high. Manual methods are based on volumetric, manometric, or gravimetric principles. Any of these approaches can provide results just as accurate and precise as automated systems, but the gravimetric approach is not sensitive to leaks or other interferences. All measurement methods require separate gas analysis or removal of carbon dioxide. When gas analysis is not available, the gas density (GD) method can be used instead. The documents below provide detailed protocols for manual methods, with new additions under development.

• Gravimetric (document 303) EN
• Gas density (document 304) EN | DE | ES

If you use these documents in your work, they should be cited. Doing so can help spread the word about the Standard BMP Methods site and contribute to standardization of BMP measurement. See the files listed below for recommended citation information. If you use Endnote, Zotero, or other reference management software, you can import the information in BibTeX file (either copy file contents to your clipboard for importing, or right-click on the link to save the file for later import). Please pay attention to version numbers when citing these documents. Changes (generally minor) will occur over time.

• Recommended citations view online
• BibTeX file for reference management software view online

Each of the documents presented here has been approved by a number of biogas researchers. For details, see the following list (use the search box to filter by document number, name or country):

• Document approval list view online

These documents represent the consensus view of many biogas researchers. Documents are developed and revised using Git and GitHub, which provide a means of tracking all changes and more. If you would like to contribute to the documents, send a message or visit the GitHub repository at https://github.com/sashahafner/BMP-methods

Numerous investigations on BMP test application and standardization have been conducted in the past few decades. Reference to state of the art guidelines and measurement methods is an essential key to achieve precise and valuable results. The papers listed below include current guidelines, describe measurement methods and report on BMP accuracy or variability. The documents listed on the Methods page synthesize much of the experience represented by these papers. Papers marked with an ► are open access and can be downloaded without a subscription. Papers marked with an ♦ can be sent to you upon request. Please use the contact page to send further suggestions.
 

Holliger, C.; Alves, M.; Andrade, D.; Angelidaki, I., Astals S.; Baier, U.; Bougrier, C.; Buffière, P.; Carballa, M.; de Wilde, V.; Ebertseder, F.; Fernández, B.; Ficara, E.; Fotidis, I.; Frigon, J.-C.; Fruteau de Laclos, H.; Ghasimi, D. S. M.; Hack, G.; Hartel, M.; Heerenklage, J.; Sarvari Horvath, I.; Jenicek, P.; Koch, K.; Krautwald, J.; Lizasoain, J.; Liu, J.; Mosberger, L.; Nistor, M.; Oechsner, H.; Vítor Oliveira, J.; Paterson, M.; Pauss, A.; Pommier, S.; Porqueddu, I.; Raposo, F.; Ribeiro, T.; Rüsch-Pfund, F.; Strömberg, S.; Torrijos, M.; van Eekert, M.; van Lier, J.; Wedwitschka, H. and Wierinck, I. (2016): Towards a standardization of biomethane potential tests. Water Science & Technology, 74 (11), 2515-2522. https://doi.org/10.2166/wst.2016.336 ►

Holliger, C.; Astals, S.; Fruteau de Laclos, H.; Hafner, S. D.; Koch, K.; Weinrich, S. (2021): Towards a standardization of biomethane potential tests: a commentary. Water Science & Technology, 83 (1), 247-250. https://doi.org/10.2166/wst.2020.569 ►

VDI 4630 (2016): Fermentation of organic substances – substrate characterisation, sampling, data collection, fermentation tests. Beuth Verlag, Düsseldorf https://www.vdi.de/richtlinien/details/vdi-4630-vergaerung-organischer-stoffe-substratcharakterisierung-probenahme-stoffdatenerhebung-gaerversuche

VDLUFA (2011): Measurement of biogas and methane yields in fermentation tests. VDLUFA Association Method, VDLUFA-Method book, Vol VII, Environmental Analysis, Method 4.1.1 Verband deutscher landwirtschaftlicher Untersuchungs- und Forschungsanstalten e.V. (Ed.), VDLUFA-Verlag, Darmstadt

Angelidaki, I.; Alves, M.; Bolzonella, D.; Borzacconi, L.; Campos, J.L.; Guwy, A.J.; Kalyuzhnyi, S.; Jenicek, P.; van Lier, J.B. Defining the biomethane potential (BMP) of solid organic wastes and energy crops: a proposed protocol for batch assays. Water Science and Technology 2009, 59, 927–934. https://doi.org/10.2166/wst.2009.040

Hafner, S.D.; Astals, S. Systematic error in manometric measurement of biochemical methane potential: Sources and solutions. Waste Management 2019, 91, 147–155. https://doi.org/10.1016/j.wasman.2019.05.001 ♦

Hafner, S.D.; Rennuit, C.; Olsen, P.J.; Pedersen, J.M. Quantification of leakage in batch biogas assays. Water Practice and Technology 2018, 13, 52–61. https://doi.org/10.2166/wpt.2018.012 ♦

Hafner, S.D.; Rennuit, C.; Triolo, J.M.; Richards, B.K. Validation of a simple gravimetric method for measuring biogas production in laboratory experiments. Biomass and Bioenergy 2015, 83, 297–301. https://doi.org/10.1016/j.biombioe.2015.10.003  ♦

Himanshu, H.; Voelklein, M.A.; Murphy, J.D.; Grant, J.; O’Kiely, P. Factors controlling headspace pressure in a manual manometric BMP method can be used to produce a methane output comparable to AMPTS. Bioresour. Technol. 2017, 238, 633–642. https://doi.org/10.1016/j.biortech.2017.04.088

Justesen, C.G.; Astals, S.; Mortensen, J.R.; Thorsen, R.; Koch, K.; Weinrich, S.; Triolo, J.M.; Hafner, S.D. Development and Validation of a Low-Cost Gas Density Method for Measuring Biochemical Methane Potential (BMP). Water 2019, 11, 2431. https://doi.org/10.3390/w11122431 ►

Owen, W.F.; Stuckey, D.C.; Healy Jr, J.B.; Young, L.Y.; McCarty, P.L. Bioassay for monitoring biochemical methane potential and anaerobic toxicity. Water Research (1979) 13, 485–492. https://doi.org/10.1016/0043-1354(79)90043-5

Richards, B.K.; Cummings, R.J.; White, T.E.; Jewell, W.J. Methods for kinetic-analysis of methane fermentation in high solids biomass digesters. Biomass and Bioenergy (1991) 1, 65–73. https://doi.org/10.1016/0961-9534(91)90028-B

Rozzi, A.; Remigi, E. Methods of assessing microbial activity and inhibition under anaerobic conditions: a literature review. Rev Environ Sci Biotechnol 2004, 3, 93–115. https://doi.org/10.1007/s11157-004-5762-z

Strömberg, S.; Nistor, M.; Liu, J. Towards eliminating systematic errors caused by the experimental conditions in Biochemical Methane Potential (BMP) tests. Waste Management 2014, 34, 1939–1948. https://doi.org/10.1016/j.wasman.2014.07.018

Raposo, F.; Fernandez-Cegri, V.; De la Rubia, M.A.; Borja, R.; Beline, F.; Cavinato, C.; Demirer, G.; Fernandez, B.; Fernandez-Polanco, M.; Frigon, J.C.; et al. Biochemical methane potential (BMP) of solid organic substrates: evaluation of anaerobic biodegradability using data from an international interlaboratory study. J. Chem. Technol. Biotechnol. 2011, 86, 1088–1098. https://doi.org/10.1002/jctb.2622

Cresson, R., S. Pommier, F. Béline, T. Bouchez, C. Bougrier, P.Buffière, J. Cacho, P. Camacho, L. Mazéas, A. Pauss, P. Pouech, T. Ribeiro, M. Rouez, M. Torrijos (2014). Etude interlaboratoires pour l'harmonisation des protocoles de mesure du potentiel bio-méthanogène des matrices solides hétérogènes. Rapport final, ADEME

Fruteau de Laclos, H., Holliger, C. (2018). Etude inter-laboratoire internationale sur les tests «BMP» - Rapport Final 2018. Project website: https://www.aramis.admin.ch/Texte/?ProjectID=33015 ►

Paterson, M., Oechsner, H. and Tillmann, P. (2020) Inter-Laboratory Test: KTBL/VDLUFA-Proficiency Test Biogas. Liebtrau, J., Pfeiffer, D. and Thrän, D. (Ed.) Collection of Measurement Methods for Biogas, Schriftenreihe des BMU-Förderprogramms „Energetische Biomassenutzung“, accepted

Hafner, S.D., Fruteau de Laclos, H., Koch, K., Holliger, C. (2020). Improving Inter-Laboratory Reproducibility in Measurement of Biochemical Methane Potential (BMP). Water, 12, 1752. https://doi.org/10.3390/w12061752 ►

Hafner, S.D., Astals, S., Holliger, C., Koch, K., Nielsen, L., Refsahl, L., Weinrich, S. (2022). Assessing the value of kinetic results from biochemical methane potential tests: Reproducibility from a large inter-laboratory study. Cleaner Chemical Engineering, 4, 100065. https://doi.org/10.1016/j.clce.2022.100065 ►

Filer, J., Ding, H. H., and Chang, S. (2019). Biochemical methane potential (BMP) assay method for anaerobic digestion research. Water, 11, 921. https://doi.org/10.3390/w11050921 ►

Weinrich, S., Schäfer, F., Bochmann, G. and Liebetrau, J. (2018). Value of batch tests for biogas potential analysis; method comparison and challenges of substrate and efficiency evaluation of biogas plants. Murphy, J.D. (Ed.) IEA Bioenergy Task 37 http://task37.ieabioenergy.com/files/daten-redaktion/download/Technical%20Brochures/Batch_tests_web_END.pdf ►

Koch, K., Hafner, S.D., Weinrich, S., Astals, S. and Holliger, C. (2020): Power and limitations of biochemical methane potential (BMP) tests. In: Frontiers in Energy Research 8, 63. https://doi.org/10.3389/fenrg.2020.00063 ►

Hafner, S.D.; Koch, K.; Carrere, H.; Astals, S.; Weinrich, S.; Rennuit, C. Software for biogas research: Tools for measurement and prediction of methane production. SoftwareX 2018, 7, 205–210. https://doi.org/10.1016/j.softx.2018.06.005 ►

These free software tools implement the equations given in the method documents, and so can be used to carry out data processing (or to check calculations). For more details, use the links below or see this paper.

Online Biogas App (OBA)

OBA is a free web application that runs in any internet browser. It can be used to: plan BMP experiments, process laboratory measurements to calculate BMP, predict biogas production based on substrate composition, and make simple conversions.

Video tutorials are available here.

The biogas package is an add-on package for the R environment that can do all that OBA can do and much more. Use requires some familiarity with the R programming language.

The package is available on CRAN, and so can be installed with install.packages("biogas") in R. For the latest version (or to submit bug reports or feature requests) see this repo on GitHub.

This website grew out a large international project on BMP standardization mainly funded by the Swiss Federal Office of Energy (SFOE), and related work carried out by a small group of researchers. While many individuals have contributed to the material presented on this website (see the author and approval lists for the methods documents), the core group responsible for content is listed below. Sören Weinrich and Sasha Hafner are responsible for site maintenance.

Sergi Astals Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Barcelona, Spain 

Sasha Hafner Department of Engineering, Aarhus University, Denmark and Hafner Consulting LLC, Reston, VA, USA.

Christof Holliger Laboratory for Environmental Biotechnology, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland

Konrad Koch Chair of Urban Water Systems Engineering, Technical University of Munich (TUM), Garching, Germany.

Sören Weinrich Biochemical Conversion Department, Deutsches Biomasseforschungszentrum gemeinnützige GmbH (DBFZ), Leipzig, Germany.

Acknowledgements

We are thankful to the following institutions for financial and technical support.

As this website is created intentionally to share current findings and enhance measurement methods for precise and standardized BMP determination, we are looking forward for comments and suggestions for improvement.

Please contact us. We are looking forward to your inquiry and will get back to you as soon as possible.