The Biochemical Methane Potential (BMP) Test
What is the BMP test?
Operators of biogas digesters can use a wide range of biodegradable feedstocks. Their potential methane yield will vary with their organic composition. The Biochemical Methane Potential (BMP) test (also known as the Biomethane Potential test) provides a standardized method for comparing the methane-generating potential of different types of feedstocks.
The value of the BMP testing protocol lies in its use of fresh digestate to closely simulate the actual microbial and environmental conditions under which the test sample is required to generate methane. The presence of non-biodegradable organics, toxic substances, and interfering byproducts will negatively affect methane yield, providing a more accurate prediction of the sample’s performance in a purely microbiological process.
- The BMP (Biochemical Methane Potential or Biomethane Potential) Test measures the maximum amount of methane that can be generated from a feedstock sample when incubated with a microbially active digestate under controlled anaerobic conditions. The final BMP biogas test results are normalized to STP (0 °C and 1 atm), enabling direct comparison of feedstocks based on their total methane potential value.
- Our Biochemical Methane Potential (BMP tests are conducted according to the German engineering standard VDI 4630 In 2024, our testing protocol was certified following participation in an international interlaboratory testing program organized by TotalEnergies (France) and Aarhus University (Denmark), and coordinated by Dr. Sasha D. Hafner. Publication: Reliable biochemical methane potential testing: insights and recommendations from global interlaboratory study.
- The standard BMP tests are performed in triplicate with inoculum blanks and a reference. Cumulative biogas and methane production is tracked throughout incubation at 37°C, yielding a final methane yield per unit feedstock. This value represents the feedstock’s biochemical methane potential (BMP).
- To accommodate clients who are working with unconventional feedstocks and digester applications, we can modify our BMP protocols while maintaining testing standards. Thai has included the use of alternative temperatures, extended incubation times, double feeding, and substrate pretreatment. This flexibility is supported by our various custom-designed test vessels and incubation systems, including integrations with the Automatic Methane Potential Test System (AMPTS® III).
The Biochemical Methane Potential (BMP) test
BMP std - Our standard and most cost-effective BMP syringe test
BMP std – This is our standard Biochemical Methane Potential test, using a syringe protocol that is most cost-effective and enables simultaneous analysis of large numbers of samples.
BMP 0.5L - 500 ml bottle test to include particles up to 1 cm
BMP 0.5L – This 500 ml bottle protocol is used to minimize sample preparation and preserve the original particle size of feedstock samples up to 1.0 cm. This more closely simulates full-scale conditions and provides sufficient sample volume for post-incubation analysis.
BMP 2.0L - 2,000 ml flask test to include particles up to 2.5 cm
BMP 2.0L – This 2,000 ml flask protocol allows inclusion of sample particles up to 2.5 cm (1”). It is often used to test fibrous organic waste and SSO samples, where the sample’s original texture must be preserved.
BMP 4.0L - 4,000 ml large volume test to include particles up 5 cm
BMP 4.0L – Our 4,000 ml large volume protocol is used to test untreated feedstock samples with particles up to 5 cm (2”). It is mainly used when the original coarse texture of the samples must be preserved and when accommodating very dilute feedstocks.
BMP adv1 - Advanced test, 2L reactor for SSO & OFMSW waste
BMP adv-1 – This Advanced 2,000 ml protocol utilizes computerized monitoring and data analysis and is combined with reactor vessels with high torque stirring designed to accept particles up to a 5 cm (2”) range. This BMP test was explicitly established to evaluate high-solids SSO and OFMSW samples. This Biogas Potential test accepts untreated samples and includes analysis of biogas VOC content.
BMP adv2 - Advanced test, customized experimental protocols
BMP adv-2 – This is an Advanced, open-ended experimental testing category that accommodates modifications to Biogas Potential analysis, such as incubation temperatures, intermittent feeding, and mid-incubation sampling.
ATR – ANAEROBIC TOXICITY RANGE
This is modified testing protocol developed by our lab to screen suspect feedstocks for their potential to cause toxic or inhibitory effects during our BMP analysis. Results ensure samples are loaded at safe concentrations to avoid having to abort tests in progress. It can also be used to quickly confirm the presence of toxic substances affecting a failing digester within in one week.
ATA – ANAEROBIC TOXICITY ASSAY
This test determines the precise concentration at which a feedstock exhibits toxicity in a digester. Their results can be interpreted in terms of an LC50 toxicity value which defines the concentration at which the sample would reduce the normal activity of a digester by 50%.
SMA – SPECIFIC METHANE ACTIVITY
The specific methane activity test is used to directly assess the viability of only the methanogens present in digestate by adding a substrate that only they can convert to methane. The rate at which methane is produced in response to the substrate spike indicates the presence and viability of the methanogens present.
RMP – RESIDUAL METHANE POTENTIAL
The residual methane potential test is used to determine the amount of methane that is being generated by a sample of spent digestate. High residual methane yields indicate incomplete conversion of substrate to methane resulting in inefficient energy conversion and potential GHG (greenhouse gas) release if land applied.