BMP testingFruit, vegetables and their residues

Peaches — BMP: 2 studies, weighted mean 344 m³ CH₄/t VS

Peaches (waste from markets and processing) contain a lot of sugars and water, so they digest well; the risks are hard stones and rapid acidification.

CH₄ ≈ 52 % (estimate)

Published 17 May 2024Updated 29 October 20263 min readFeedstockData Editorial Team

Photo Jack Dykinga, USDA / Wikimedia Commons, public domain, source file; changes: cropping

Weighted mean: 344m³ CH₄/t VS
Range: 334–353m³ CH₄/t VS
Records: 2studies
Publications: 2sources
Temperatures: 35 °Cof the test

Methane in biogas

≈51–54% CH₄

Medium methane content · ≈ 5.2 kWh/m³ of biogas

estimate from the substrate type The collected studies contain no measurement. The interval follows from the approximate composition (carbohydrate-dominated (no protein or fat characteristics)) and the yields of compound groups according to FNR.

How we calculate it and what the zones mean

Rating for biogas plants

not rated — editorial rating for biogas plants

Not rated: no dry matter or volatile solids in the data. We calculate the rating when the dry matter and volatile solids of the material are known.

Editorial rating per the methodology

Add to the co-digestion calculator CSV data

BMP curves from 2 studies

Weighted mean Individual records

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 (344); 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

Source	BMP m³ CH₄/t VS	Temperature	Sample	Curve
Aybek et al. (2017) DOI	353	—	Peach	end point (model curve)
Kouas et al. (2017) DOI	334	35 °C · mesophilic	peach	end point (model curve)
Weighted mean	344	arithmetic mean 344, SD 13

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

combines well
substrates: nitrogen-rich — e.g. Pig slurry, Poultry manure, Waste activated sludge (secondary sludge), Chlorella vulgaris, Nannochloropsis salina
A nitrogen-rich co-substrate balances the low C/N of fruit and vegetable waste (Bouallagui et al. 2009).^[1]
combines well
substrates: high alkalinity (buffer) — e.g. Cattle manure, Pig slurry, Cattle slurry, Duck slurry, Rumen and digestive tract content
Co-digestion of easily degradable substrates with dairy slurry increased the methane yield relative to slurry alone.^[2]

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

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

What it is and where it comes from

Peaches are fruit grown in orchards in warmer regions, also in Poland on a small scale. Waste arises during sorting, in processing (pulps, canned goods) and in retail, where damaged and overripe fruit is rejected. The dataset contains several records: peach waste from a market, ground to particle sizes of 1 and 3 mm, and a sample with no detailed description, tested at mesophilic temperature.

Properties relevant to digestion

The flesh consists of water (over 85%), simple sugars and pectins, which are rapidly degraded. The ready availability of sugars promotes abrupt acidification at a high dose. The stones have hard shells rich in lignin, which degrade very poorly, and the seeds contain amygdalin, which releases hydrogen cyanide, although in amounts that are not a barrier in typical waste streams. The skins contain pectins and polyphenols. A low protein content means a low risk of ammonia.

How to read the spread of results

The records are similar, but come from different studies, and the result depends on the share of stones, the ripeness of the fruit, the variety and the degree of size reduction (one study compared grinding to two sizes). Temperature, inoculum, the substrate-to-inoculum ratio and test length are significant, as is the method of conversion to VS. A small number of records does not indicate a typical range for peaches.

In biogas plant practice

Peaches can be used as a co-substrate in installations accepting waste from fruit sorting and processing, best in a mixture with buffering materials. Stones should be removed or well size-reduced so that they do not damage pumps. Dosing should be even and prompt after delivery. Fruit waste is usually classified as waste (group 02 or 20), and its acceptance requires installation permits; plant raw material is not subject to the regulations on animal by-products.

For comparison with apples, peaches have soft flesh, so they are easier to size-reduce, but the stone makes up a larger part of the mass. The flesh alone degrades very well, and its share in the waste is the main factor determining the result. The method of separating the stones should therefore be agreed with the supplier.

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

All sources of the site: bibliography.