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BMP testingFruit, vegetables and their residues

Whole tropical fruit (papaya, mango) — BMP: 2 studies, weighted mean 333 m³ CH₄/t VS

Whole tropical fruit (papaya, mango) is a material rich in sugars and water; records from different studies describe rejected fruit or fruit processed whole.

rating: neutralCH₄ ≈ 56 % (estimate)

Published Updated 3 min readFeedstockData Editorial Team

Photo Ivar Leidus / Wikimedia Commons, licence CC BY-SA 4.0, source file; changes: cropping

Weighted mean
333m³ CH₄/t VS
Range
306–360m³ CH₄/t VS
Records
2studies
Publications
2sources
Temperatures
35 °C, 37 °Cof the test

Methane in biogas

Medium methane content · ≈ 5.6 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 4.2 % 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 (33 m³ CH₄/t); process risk: acidification. No additional handling requirements.

Why? Rating factors

Potential per tonne +1

  • +1potential 33 m³ CH₄/t fresh matter (BMP 333 × DM 10.7 % × VS 92.4 %)

Process stability −1

  • −1acidification: rapid degradation / acidic pH, risk of VFA accumulation, needs buffering

Handling and costs 0

  • 0no factors

Total points: 0 · thresholds: ≥ 2.5 very good, ≥ 1 good, below — neutral; negative with cumulative process risk.

Editorial rating per the methodology · confidence of the rating: low · excluding market prices

Add to the co-digestion calculator CSV data

BMP curves from 2 studies

Weighted mean Individual records

BMP curves: Whole tropical fruit (papaya, mango)Cumulative methane production over time for 2 records and the weighted mean of 333 m³ CH₄/t VS. 2 of the curves are model curves (first-order kinetics).0100200300400051015202530time [d]m³ CH₄/t VSGe et al. (2014): 360 m³ CH₄/t VS (model curve)Kouas et al. (2017): 306 m³ CH₄/t VS (model curve)mean333

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

Cumulative methane production over the test [m³ CH₄/t VS]. The thick line is the weighted mean of all records (333); 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.

Records and sources

Download CSV
SourceBMP
m³ CH₄/t VS		TemperatureSampleCurve
Ge et al. (2014) DOI36037 °C · mesophilicpapayaend point (model curve)
Kouas et al. (2017) DOI30635 °C · mesophilicmangoend point (model curve)
Weighted mean333arithmetic mean 333, SD 38

Typical composition

Dry matter (DM)
10.7% (range 10.7–10.7)
Volatile solids (VS)
92.4 % DM (range 92.4–92.4)
Nitrogen
4.2 % DM
C/N ratio
12.4

Median and range of the determinations reported in the publications behind this substrate's BMP records (read from: MY-D); dry matter: 1 determination, volatile solids: 1 determination. C/N was calculated as the ratio of C and N content (% DM) from the same source. DM from a single determination – indicative value.

Sources: Ge et al. (2014).

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

Low confidence: the description is based on general characteristics of the substrate group, not on studies of this material. Treat it as a hint to be verified.

No published process studies

The literature we use does not describe the advantages or drawbacks of digesting this substrate beyond the BMP test results. Below are process characteristics assigned on the basis of the type of material — an editorial classification, not a study result.

easily degradable
sugars, starch, glycerol → fast hydrolysis and acidification (VFA), needs buffering
acidic
low pH of the substrate (silages, stillage, whey, fruit)
dilutes the feed (low DM)
low dry matter, dilutes the feed
seasonal
seasonal availability — requires storage
poor in trace elements
poor in trace elements — mono-digestion requires supplementation
carbon-rich
high C/N → nitrogen deficiency; combine well with nitrogen-rich substrates
low in nitrogen
high C/N → nitrogen deficiency; combine well with nitrogen-rich substrates

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

Dosing

No source limits on the dose for this substrate.

Introduce gradually, starting with a small dose and monitoring the process (e.g. FOS/TAC, pH, gas composition).

Sources of the process data

  1. Improvement of fruit and vegetable waste anaerobic digestion performance and stability with co-substrates addition
  2. Biochemical methane potential and biodegradability of complex organic substrates
  3. Biogas energy production from tropical biomass wastes by anaerobic digestion
  4. Robust assessment of both biochemical methane potential and degradation kinetics of solid residues in successive batches
  5. Effects of size and thermophilic pre-hydrolysis of banana peel during anaerobic digestion, and biomethanation potential of key tropical fruit wastes
  6. Effect of particle size on biogas generation from biomass residues

The co-digestion calculator will assess a specific mixture containing this substrate.

What it is and where it comes from

Papaya (Carica papaya) and mango (Mangifera indica) are tropical fruits grown on a large scale in Asia, Africa and the Americas. A considerable part of production is lost at harvest, transport and sale because of spoilage and damage, and fruit that fails commercial standards is sent for feed, compost or to biogas plants. The entry concerns whole fruit, without separating peel, pulp and stone; the peels of other tropical fruits are covered in a separate entry.

Properties relevant to digestion

The pulp of the fruit contains simple sugars, pectins and small amounts of protein, so it degrades quickly and gives a rapid increase in organic acid production. Too sudden a load can lower the pH and inhibit methanogenesis. Pectins can increase the viscosity of the suspension. Whole mango fruit contains a hard stone, which degrades more slowly than the pulp, and papaya contains numerous small seeds. A high water content means a low concentration of energy per tonne of fresh matter.

How to read the spread of results

The records concern two different species from different studies and temperatures close to mesophilic, so their comparison is not a repetition of the same measurement. The result is influenced by the variety, the degree of ripeness or spoilage (overripe fruit has a different composition), the share of seeds and peel, size reduction, moisture and the way of converting to volatile solids. Literature values can therefore indicate only an order of magnitude for fruit with well-mixed fractions.

In biogas plant practice

In tropical countries rejected fruit is a seasonal supplement to the mix. In Poland such streams are small quantities from wholesalers and exotic fruit processors, usually mixed with other fruit and vegetable waste. The basic rules are to crush the stones, feed gradually, monitor pH and volatile fatty acids, and choose a tank with a buffer reserve. Food waste is waste within the meaning of the waste act, so its acceptance requires a permit.

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 = 0.245 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. Ge, X.; Matsumoto, T.; Keith, L.; Li, Y. (2014). Biogas energy production from tropical biomass wastes by anaerobic digestion. Bioresource Technology 169, 38–44. DOI: 10.1016/j.biortech.2014.06.067 DOI
  2. Kouas, M.; Torrijos, M.; Sousbie, P.; Steyer, J.P.; Sayadi, S.; Harmand, J. (2017). Robust assessment of both biochemical methane potential and degradation kinetics of solid residues in successive batches. Waste Management 70, 59–70. DOI: 10.1016/j.wasman.2017.09.001 DOI

All sources of the site: bibliography.

Other substrates in the group “Fruit, vegetables and their residues”