BMP (biochemical methane potential) is the amount of methane that can be obtained from a unit of organic mass of a substrate in a batch test. We compile the results of many publications for each substrate, calculate a weighted mean and show all the curves at once.
RSSEach article in this category concerns one substrate and combines records from several independent studies: the final value, temperature, sample description and the full source. Results are given in m³ CH₄ per tonne of volatile solids (m³ CH₄/t VS, numerically equal to NmL CH₄/g VS), at normal conditions.
A missing measurement in a BMP test is a common situation. We show what interpolation can and cannot change in the result, how to flag it and why the end of the curve must not be "written in".
A BMP test measures how much methane can be obtained from a given substrate under anaerobic conditions. We explain the course of the test, the units, interpretation of the curve and situations in which it is worth ordering one.
A review of three Japanese studies on the methane potential of rice straw, manure and food waste: BMP from 1999, co-digestion of feed rice (2012) and solid-state thermophilic co-digestion (2022).
What a reliable BMP report must contain, how to assess the cellulose control and the blank, what to look at in the curves and when to commission a repeat test.
The BMP result refers to volatile solids (VS), so its determination is the foundation. How drying and ignition work, where losses of volatiles come from and how to avoid them.
How biogas and methane production is measured in BMP bottles, what errors are made when converting to standard conditions and how to avoid overstating the result.
Two documents often cited in fermentation test reports: the German guideline VDI 4630 and the standard ISO 11734. We explain their scope and why they are not interchangeable.
How to calculate the maximum yield of CH₄ and CO₂ from a molecular formula or elemental composition. Three numerical examples, the limitations of the method and comparison with the BMP result.
Why does the same silage give different BMP in different laboratories? A review of the sources of scatter, measures (SD, RSD, z-score), an example and rules for comparing results.
When a BMP curve has a lag phase and a sigmoidal shape, the modified Gompertz model is used. We explain the parameters P, Rm and λ, and show a calculation and the pitfalls.
How can a BMP curve be described with a single equation? The first-order model gives B₀, the rate constant k and the t90 time. We show the fitting, an example and the limitations of the model.
Why does laboratory BMP usually exceed the actual yield of a plant? We break the difference down into factors: time, kinetics, losses, data errors and measurements. With a worked example.
Two studies on Korean food waste: Cho et al. (1995) – a mixture BMP of 472 mL CH₄/g VS and dry digestion – and Lee et al. (2009) – a leachate BMP of 358–478 mL/g VS and the effect of temperature, alkalinity and salinity.
Calculation errors can change a BMP result by several to a dozen or so per cent. We discuss the corrections: dry gas, water vapour, headspace, solubility and gas mass.
An Australian study in Bioresource Technology (volume 391, 2024) measures the methane potential of dairy cattle manure across the country and shows that mechanical separation preserves B₀, while passive separation lowers it.
What a recognised review of BMP standardisation recommends: number of replicates, I/S, cellulose control, termination criterion and reporting. We discuss them and show how to use them.
Two elements determine the reliability of a test: the blank (inoculum background) and the positive control with cellulose. We explain their role, acceptance criteria and the consequences of failure.
I/S decides whether a BMP test ends in a result or an acidified bottle. The formula, guideline recommendations, a calculation example and the consequences of too low or too high an I/S.
The inoculum determines the reliability of a BMP test. We discuss sources, degassing, control parameters (VS, pH, alkalinity, VFA, NH₄⁺) and the effect on kinetics and result.
The full path of a batch test: sample preparation, inoculum, filling, incubation, gas measurement, termination and calculations. With a checklist and typical mistakes.
BMP is the maximum amount of methane that can be obtained from a unit of a substrate's organic matter in an anaerobic batch test. We explain what it is used for and what it does not tell you.
We analyse Brazilian BMP studies of vinasse: optimisation of the F/M ratio (95% of theoretical BMP), a review range of 215–324 L CH₄/kg organic matter, and warnings about comparing units.
A paper from the University of Waikato in “Energies” (2023) combines a literature review, surveys, chemical analyses and BMP tests to assess biogas from dairy farm manure.
A 2018 study assessed the methane potential of coffee processing waste in Ethiopia: from about 31 NmL CH₄/g VS (parchment) to about 295 (mucilage). We add the context of research on water hyacinth.
