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BMP testingAnimal excreta (slurry, manure, poultry litter)

Human faeces/excreta — BMP: 2 studies, weighted mean 322 m³ CH₄/t VS

Human faeces and excreta were studied in the context of sanitation in developing countries; it is a nitrogen-rich material requiring hygienisation and caution.

CH₄ ≈ 56 % (estimate)

Published Updated 3 min readFeedstockData Editorial Team

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

Weighted mean
322m³ CH₄/t VS
Range
254–390m³ CH₄/t VS
Records
2studies
Publications
2sources
Temperatures
30 °Cof the test

Methane in biogas

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 (nitrogen-rich (process classification)) 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

BMP curves: Human faeces/excretaCumulative methane production over time for 2 records and the weighted mean of 322 m³ CH₄/t VS. 2 of the curves are model curves (first-order kinetics).0100200300400500051015202530time [d]m³ CH₄/t VSDonacho et al. (2023): 390 m³ CH₄/t VS (model curve)Osei-Owusu et al. (2024): 254 m³ CH₄/t VS (model curve)mean322

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 (322); 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
Donacho et al. (2023) DOI390—Human feces (mean of 3 BMP experiments)end point (model curve)
Osei-Owusu et al. (2024) DOI25430 °C · mesophilicHuman excreta (HE)end point (model curve)
Weighted mean322arithmetic mean 322, SD 96

Process properties

  • nitrogen-rich
  • variable composition
  • dilutes the feed (low DM)
  • editorial classification

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.

Advantages

  • Methane potential in the Substraty.pl BMP set: weighted mean 321.9 m³ CH₄/t VS (SD 96.2; 2 records, 2 sources).
  • It degrades more readily than herbivore lignocellulosic excreta; it is a source of N (Rose et al. 2015).

Drawbacks and risks

  • Pathogens survive mesophilic digestion: hygienisation of the digestate is necessary (Rose et al. 2015).
  • Composition depends on diet and the collection system (latrines).

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

Dosing

No source threshold; data from sanitation, not from agricultural biogas plants. Do not dose into a feed containing ABP without agreement with the authority.

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

Sources of the process data

  1. Rajagopal, Masse, Singh (2013). A critical review on inhibition of anaerobic digestion process by excess ammonia. Bioresour. Technol.
  2. Rose et al. (2015). The characterization of feces and urine: a review of the literature to inform advanced treatment technology. Crit. Rev. Environ. Sci. Technol.

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

What it is and where it comes from

Human faeces and excreta are material from toilets, latrines and septic tanks, considered as a substrate in sanitation projects, particularly where there is no sewerage. The dataset contains several records: fresh faeces from Ethiopia (a mean of several experiments) and excreta from latrines in Ghana. In countries with sewerage these excreta go to wastewater treatment plants and pass into sludge, rather than into separate digestion.

Properties relevant to digestion

Faeces consist in large part of bacterial biomass, undigested food residues and water. They are rich in nitrogen, but degrade relatively easily compared with the lignocellulosic excreta of herbivorous animals. The composition depends on the diet. Material from latrines is usually a mixture of faeces, urine, water, paper and contaminants, and during storage it undergoes partial degradation, which reduces the potential. The main problem is pathogens (bacteria, viruses, parasite eggs), a significant proportion of which survive mesophilic digestion.

How to read the spread of results

The records come from different countries and systems: some concern fresh faeces, and some excreta from latrines after storage. The differences reflect the diet, the degree of decomposition in the latrine, dilution with water, and the presence of urine, paper, sand and other contaminants. In addition, temperature, inoculum and the substrate-to-inoculum ratio have an effect. A small number of records does not allow the results to be generalised.

In biogas plant practice

In Poland human excreta are not a substrate for agricultural biogas plants; they go to the sewerage system, and after treatment sewage sludge arises, which is digested in the digesters of treatment plants. In developing countries, biogas plants at toilets (for example institutional ones) serve sanitation and the production of gas for cooking. The digestate requires hygienisation before it is used as a fertiliser. Legal requirements depend on the country; in the European Union, sewage sludge and the regulations on its use are governed by separate legislation.

For comparison with municipal wastewater, in which faeces are strongly diluted, material from latrines is concentrated, but variable. The results from this compilation are therefore significant mainly for sanitation projects, not for installations in Europe.

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 = 0.393 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. Donacho, D.O.; Tucho, G.T.; Olani, D.D.; Kabtiyimer, H.E.; Hailu, A.B.; Wolde, A.D. (2023). Experimental evaluation of fresh human feces biogas and compost potential: Evidence for circular economy from waste streams in Ethiopia. Heliyon 9(12), e22494. DOI: 10.1016/j.heliyon.2023.e22494 DOI
  2. Osei-Owusu, B.A.; Arthur, R.; Baidoo, M.F.; Oduro-Kwarteng, S.; Amenaghawon, A.N. (2024). Anaerobic co-digestion of human excreta, food leftovers and kitchen residue: 1 ternary mixture design, synergistic effects and RSM approach. Heliyon 10(2), e24080. DOI: 10.1016/j.heliyon.2024.e24080 DOI

All sources of the site: bibliography.

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