BMP testingFruit, vegetables and their residues

Fruit and vegetable waste (mixed) — BMP: 5 studies, weighted mean 305 m³ CH₄/t VS

Mixed fruit and vegetable waste (e.g. from supermarkets) digests easily, but the composition is variable; contaminants and acidification must be expected.

rating: neutral CH₄ ≈ 55 % (estimate)

Published 27 February 2020Updated 29 October 20263 min readFeedstockData Editorial Team

Illustration: FeedstockData (AI, Google Gemini)

Weighted mean: 305m³ CH₄/t VS
Range: 160–400m³ CH₄/t VS
Records: 5studies
Publications: 3sources
Temperatures: 36 °C, 37 °Cof the test

Methane in biogas

≈54–57% CH₄

Medium methane content · ≈ 5.5 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 3.3 % 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 (48 m³ CH₄/t); process risk: acidification. No additional handling requirements.

Why? Rating factors

Potential per tonne +1

+1potential 48 m³ CH₄/t fresh matter (BMP 305 × DM 17.6 % × VS 89.2 %)

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: high · excluding market prices

Add to the co-digestion calculator CSV data

BMP curves from 5 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 (305); 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
Alkanok et al. (2014) DOI	400	36 °C · mesophilic	fruit, vegetable and flower waste	end point (model curve)
Li et al. (2013) · 1 DOI	267	—	Fruit and vegetable mixed waste (Fruit and vegetable mixed waste)	end point (model curve)
Bouallagui et al. (2005) · 1 DOI	160	—	Fruit and vegetable wastes	end point (model curve)
Bouallagui et al. (2005) · 2 DOI	260	—	Fruit and vegetable wastes	end point (model curve)
Li et al. (2013) · 2 DOI	342	37 °C · mesophilic	Fruit and vegetable waste	end point (model curve)
Weighted mean	305	arithmetic mean 286, SD 91

Typical composition

Dry matter (DM): 17.6% (range 3.7–31.6)
Volatile solids (VS): 89.2 % DM (range 85–89.2)
Nitrogen: 3.3 % DM
C/N ratio: 13.1

Median and range of the determinations reported in the publications behind this substrate's BMP records (read from: BCBPD, MY-D); dry matter: 2 determinations, volatile solids: 3 determinations. C/N was calculated as the ratio of C and N content (% DM) from the same source.

Sources: Alkanok et al. (2014); Li et al. (2013); Li et al. (2013).

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

easily degradable
acidic
dilutes the feed (low DM)
seasonal
poor in trace elements
carbon-rich
low in nitrogen
variable composition
editorial classification

Advantages

Methane yield in the compendium: median 267 (range 160–400) m³ CH₄/t VS, 5 records from 4 papers (weighted mean 305).
Supermarket waste (fruit and vegetables) was studied as a biogas source (Alkanok et al. (2014))
Fruit and vegetable waste was digested stably in ASBR reactors (load approx. 2.5 g VS/l·d, HRT 10 d, approx. 90% VS from fruit and vegetable waste) after the addition of a nitrogen-rich co-substrate (Bouallagui et al. (2009))

Drawbacks and risks

Mixed waste varies in composition between batches, which makes it difficult to maintain a constant dose (Alkanok et al. (2014))
Fruit and vegetable waste is low in nitrogen (C/N 34.2 in the Bouallagui study; a C/N range of 22–25 was considered better for co-digestion) — digestion on its own requires a nitrogen-containing co-substrate (Bouallagui et al. (2009))
Digestion of fruit and vegetable waste on its own can be unstable (imbalance between bacterial groups); the addition of fish waste lowered the VFA/alkalinity ratio to 0.28 and allowed digestion without adding alkali (Bouallagui et al. (2009))

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
Nitrogen-rich co-substrates (fish waste, slaughterhouse wastewater, activated sludge) improved the stability or yield of fruit and vegetable waste digestion; best co-digestion C/N 22–25.^[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

The sources do not give a safe share of this substrate in the feed. For fruit and vegetable waste as a class: stable operation of ASBR reactors (load approx. 2.5 g VS/l·d, HRT 10 d, approx. 90% VS from fruit and vegetable waste) was achieved after the addition of a nitrogen-rich co-substrate; the best co-digestion C/N was considered to be 22–25 (Bouallagui et al. 2009). Adding 10% VS of slaughterhouse wastewater or activated sludge increased biogas production by approx. 51.5% and 43.8%.

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

Practical requirements

Supermarket waste requires sorting to remove packaging (Alkanok et al. (2014))
Monitor the VFA/alkalinity ratio (in the Bouallagui study a value of 0.28 corresponded to stable operation) (Bouallagui et al. (2009))

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

Mixed fruit and vegetable waste arises in retail and wholesale trade, in markets, in sorting plants and in processing. A typical example is waste from supermarkets: fruit and vegetables unfit for sale, often together with potted plants and flowers. This stream is variable over time and depends on the season, the range of products and the shop's purchasing policy.

Properties relevant to digestion

The material is very watery, and its dry matter contains mainly simple sugars, starch, pectins and fibre, with a low content of lignin and fats. The protein content is usually small, so the C/N ratio is high and combining with nitrogenous material is justified. Rapid hydrolysis leads to the formation of acids and a drop in pH, especially when the batch contains a lot of fruit with a low pH, such as citrus or apples. With admixtures, one must expect plastic packaging, labels, stones from stone fruit, and sand and soil, which require separation before the digester.

How to read the spread of results

The spread for this category is predictably large, because "fruit and vegetable waste" does not describe a single material, but a moving mixture. The dataset includes records from several studies, some with no temperature stated, one under mesophilic conditions, and of different origin (supermarket, mixed vegetable waste). The result depends on the proportions of fruit, leafy vegetables, roots and flowers, on freshness, comminution and the inoculum. For such a complex stream, a test of your own batch is therefore always the most reliable.

In biogas plant practice

Fruit and vegetable waste is well suited to co-digestion with slurry or sludge, but requires segregation and shredding. Contaminants are usually removed before the digester, and if packaging is present, separation or depackaging is applied. Dosing should be even, because large one-off deliveries risk acidification. The material spoils quickly, so it is not suitable for long storage. Food waste of plant origin is waste, and its acceptance is subject to the waste rules and the entries in the installation's permit; if the stream contains products of animal origin, additional veterinary requirements come into play.

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.