Development and Validation of a Low-Cost Gas Density Method for Measuring Biochemical Methane Potential (BMP)

Camilla G. Justesen, Sergi Astals*, Jacob Rosholm Mortensen, Rasmus Thorsen, Konrad Koch , Sören Weinrich, Jin Mi Triolo, Sasha D. Hafner

*Corresponding author for this work

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Accurate determination of biochemical methane potential (BMP) is important for both biogas research and practice. However, access to laboratory equipment limits the capacity of small laboratories or biogas plants to conduct reliable BMP assays, especially in low- and middle-income countries. This paper describes the development and validation of a new gas density-based method for measuring BMP (GD-BMP). In the GD-BMP method, biogas composition is determined from biogas density. Biogas density is based on bottle mass loss and biogas volume, and these can be accurately measured using only a standard laboratory scale, inexpensive syringes, and a simple manometer. Results from four experiments carried out in three different laboratories showed that the GD-BMP method is both accurate (no significant bias compared to gravimetric or volumetric methods with biogas analysis by gas chromatography) and precise (<3% relative standard deviation is possible). BMP values from the GD-BMP method were also comparable to those measured for the same substrates with an industry standard automated system (AMPTS II) in two independent laboratories (maximum difference 10%). Additionally, the GD-BMP method was shown to be accurate even in the presence of leakage by excluding leakage from mass loss measurements. The proposed GD-BMP method represents a significant breakthrough for both biogas research and the industry. With it, accurate BMP measurement is possible with only a minimal investment in supplies and equipment.
Original languageEnglish
Article number2431
Issue number12
Number of pages17
Publication statusPublished - 20. Nov 2019



  • Anaerobic digestion
  • Batch assays
  • Biogas technology
  • Biomethane potential
  • Gravimetric determination
  • Inexpensive laboratory method
  • Inter-laboratory comparison

Cite this

G. Justesen, C., Astals, S., Mortensen, J. R., Thorsen, R., Koch , K., Weinrich, S., Triolo, J. M., & Hafner, S. D. (2019). Development and Validation of a Low-Cost Gas Density Method for Measuring Biochemical Methane Potential (BMP). Water, 11(12), [2431].