FAQ: About the site

The BMP values in the service are good for preliminary comparisons and estimates, but investment and recipe decisions should be based on tests of your own substrates in an accredited or trusted laboratory.

Data from the literature come from different conditions and often from samples that are not representative of a specific supplier. The range of results on a substrate page shows how large the differences are. The service accepts no liability for damage resulting from using the data without verification. Use them as a starting point, not as the basis of a guarantee.

Sources: Substraty.pl — kompendium wiedzy o biogazie i biometanie

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No, the content of Substraty.pl is informational and does not replace a technical design, an expert opinion, a laboratory test or legal advice.

Biogas plants are facilities with explosion hazards and toxic gases; technical and safety decisions require specialists and documentation. The descriptions on the site present typical ranges and principles, which may differ in specific conditions. If in doubt, consult a designer, a service technician or a laboratory.

Sources: Substraty.pl — kompendium wiedzy o biogazie i biometanie

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Yes, but each record has its temperature and regime (mesophilic, thermophilic) recorded, so it is possible to assess whether differences result from the conditions rather than from the substrate.

The chart legend shows the sample description and the source. The weighted average takes into account all records with weights, so where temperatures differ greatly it is worth analysing the mesophilic and thermophilic records separately. If the records differ strongly, the average should not be treated as a single "true" value.

Sources: Towards a standardization of biomethane potential tests — Holliger et al., Water Sci. Technol. (2016)

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In the weighted average each publication has a total weight of 1, divided equally among its records for a given substrate — so a single paper with many varieties or harvest dates does not dominate the result.

Example: if article A gives three results for silage and article B one, each result from A has a weight of 1/3, and the result from B a weight of 1. For data from interlaboratory studies with actual curves, the weights depend on the number of test bottles, normalised per laboratory. The weighting rule is described next to the chart, and the weighted average is shown alongside the arithmetic mean, standard deviation and min–max range. The weighted average is an indicative tool — it does not replace testing your own sample, because the real BMP depends on the variety, harvest date and conditions.

Sources: Substraty.pl — kompendium wiedzy o biogazie i biometanie

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Content is added on an ongoing basis, and articles on regulations include a publication date and, where the legal status has changed, an update note.

Entries describe the situation as at the publication date, and later changes (amendments, new data) are marked in the "Current status" field. The FAQ has a review date. For important decisions, always check legal acts in official sources (e.g. EUR-Lex, ISAP, gov.pl) — the site does not replace official texts.

Sources: Substraty.pl — kompendium wiedzy o biogazie i biometanie

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When citing, give the name of the site, the page title, the date of access and the URL; for BMP data, also cite the original publication indicated in the chart legend.

Example: "Substraty.pl, page title, accessed: date, address". For BMP results it is best to refer to the primary source (DOI), because the site is a compilation and does not replace the publication. The site's content is protected by copyright; short quotations with the source given are permitted within the limits of the law. Longer use requires the publisher's consent.

Sources: Substraty.pl — kompendium wiedzy o biogazie i biometanie

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You can contact the editorial team by e-mail: biuro@substraty.pl. Messages may concern content, BMP data, paid services and cooperation.

To speed up the reply, give the subject (e.g. correction, advertising, BMP test), the page address and your contact details. The editorial team does not provide individual technical or legal advice, but it can point to sources that deal with such matters. Response time depends on the number of enquiries.

Sources: Substraty.pl — kompendium wiedzy o biogazie i biometanie

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A multi-BMP chart shows on one figure the methane production curves from several publications (thin lines) and a thick line for the weighted average, which makes it possible to assess both the typical level and the spread of results.

The vertical axis is cumulative methane in m³ CH₄ per tonne of organic dry matter (m³ CH₄/t s.m.o.), and the horizontal axis is time in days. The "measured" lines are based on points from publications, and the "modelled" ones are drawn from the first-order model and have an end point consistent with the result from the article; they are clearly marked. The legend links to the bibliography. A narrow bundle does not always mean low variability, because some authors use similar methods.

Sources: Substraty.pl — kompendium wiedzy o biogazie i biometanie

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An error or a proposed correction can be reported through the contact form in the service, giving the page address, a description of the problem and, if possible, the source (e.g. the DOI of the publication).

The editorial team verifies reports, checks the data in the source publication and corrects the content, and in the case of significant changes adds an update note. Reports concerning BMP values, units, conversions and the currency of regulations are particularly valuable. Anonymous reports are also considered, but they are easier to verify when they include a reference to a source.

Sources: Substraty.pl — kompendium wiedzy o biogazie i biometanie

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Yes, access to articles, the FAQ and substrate data is free for readers; only optional services are paid: a sponsored article and a commissioned BMP test.

Paid services are described in the Paid Services Terms. Revenue from them does not affect editorial content or BMP values. Educational content may contain links to external sources; the editorial team is not responsible for their content.

Sources: Substraty.pl — kompendium wiedzy o biogazie i biometanie

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Editorial content (articles, FAQ, BMP data) is prepared independently of companies and sponsors, and paid services give no influence over its content.

Sponsored articles are clearly labelled. The editorial team does not accept payment for positive descriptions in editorial articles or for modifications of BMP data. If you notice a conflict of interest, write to biuro@substraty.pl and the editorial team will look into the matter.

Sources: Substraty.pl — kompendium wiedzy o biogazie i biometanie

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No, the BMP database does not cover all published results, but a selection of records with documented methodology, and it is expanded as new publications are verified.

The number of records differs between substrates: it is larger for popular ones (maize silage, slurry) and smaller for rarer ones, which affects the reliability of the average. The substrate page shows the number of records and sources. The absence of a result does not mean the absence of potential, only the absence of adequately documented data.

Sources: Substraty.pl — kompendium wiedzy o biogazie i biometanie

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The site is based on published sources, so your own result can be submitted if it has been described in a publication, report or document that allows the method and conditions to be verified.

The submission should include the substrate, the result in m³ CH₄/t VS or NmL CH₄/g VS (or in another unit with a description of the conversion), the temperature, ISR, test duration, information on the cellulose control and a link to the source. The editorial team decides on inclusion in the database; an included result is subject to the same weighting rule as the others (a total weight of 1 per publication). Results that cannot be verified are not included in the weighted average.

Sources: Substraty.pl — kompendium wiedzy o biogazie i biometanie

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Substraty.pl is a Polish-language compendium of knowledge about biogas, biomethane and substrates, combining a database of BMP results with articles, guides and FAQ.

The service has been operating since December 2019. It contains substrate pages with charts of methane potential and a weighted average from many publications, as well as news and analyses. The content is informational and educational in nature; it does not replace a technical design, a laboratory test or legal advice.

Sources: Substraty.pl — kompendium wiedzy o biogazie i biometanie

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The site covers biogas, biomethane, bioLNG and bioCNG, biohydrogen, BMP testing, digestate, technology and operation, waste, law, the market and climate. Each category has articles, guides and FAQ, and substrate pages — BMP data with charts. A bibliography of sources is also available. Content is prepared by the "Substraty.pl Editorial Team" on the basis of primary sources (legal acts, scientific publications, institutional reports). The site is being expanded, and new topics appear as regulations and the market change.

Sources: Substraty.pl — kompendium wiedzy o biogazie i biometanie

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BMP data come from peer-reviewed scientific publications and studies by research institutions; each record has an assigned source with a full bibliographic description and a link (DOI or address).

The editorial team collects the results, records the test conditions (temperature, pretreatment, sample description), converts them to a common unit of m³ CH₄/t s.m.o. (numerically the same as NmL CH₄/g VS) and retains the original value together with its unit. These are not the results of the service's own laboratory tests. The full list of publications is available in the bibliography, and every record can be traced back to its source.

Sources: Substraty.pl — kompendium wiedzy o biogazie i biometanie; Towards a standardization of biomethane potential tests — Holliger et al., Water Sci. Technol. (2016)

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The site is intended for farmers and investors planning a biogas plant, plant operators, laboratories, technology suppliers, students and anyone interested in energy from biogas.

The content has varying levels of detail: from simple answers in the FAQ to extensive guides. Operators will find information on process parameters, laboratories on BMP methodology, and investors on legal requirements and economics. All users should verify the details in primary sources. The site does not require registration, and the content is available free of charge to all readers.

Sources: Substraty.pl — kompendium wiedzy o biogazie i biometanie

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The Substraty.pl service is published and run by Samael Sp. z o.o., based in Tarnów.

The content in the service is signed "Redakcja Substraty.pl" (the Substraty.pl editorial team). The service is an independent source of information about the industry; sponsored materials are clearly marked, and the editorial team does not promise that paid cooperation will influence test results or assessments. The publisher's contact details are in the footer and on the service's contact page.

Sources: Substraty.pl — kompendium wiedzy o biogazie i biometanie

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Methane per tonne of volatile solids (m³ CH₄/t VS, under normal conditions) is a practical unit for biogas plants and is numerically exactly the same as NmL CH₄/g VS — the standard in the scientific literature (1 NmL/g = 1 m³/t). Referring to volatile solids makes it possible to compare substrates regardless of water and ash content, and giving methane (not biogas) makes the result independent of how much CO₂ has dissolved in the liquid. We show the methane share of the biogas separately, on the indicator for each substrate.

Values from publications in other units (e.g. m³ CH₄/t VS, NL/kg oS, mL/g TS) are converted while the original value and unit are retained in the data. If the author gives the result per dry matter (TS) rather than VS, the conversion requires information on the VS share of TS; where no such information is available, the record is not included.

Sources: Towards a standardization of biomethane potential tests — Holliger et al., Water Sci. Technol. (2016)

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A substrate may have synonyms (e.g. "kiszonka z kukurydzy", "kiszonka kukurydziana", "maize silage"), which the site takes into account in the search and on the page so as not to duplicate records.

Names differ in the literature, and translations into English are not always unambiguous. The editorial team tries to assign results to the correct substrate on the basis of the sample description, and uncertain cases are flagged or omitted. If you notice an incorrect assignment, submit a correction.

Sources: Substraty.pl — kompendium wiedzy o biogazie i biometanie

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The min–max range and the standard deviation show the spread of results from different publications, which matters because the average alone hides the variability of the substrate.

A large deviation indicates that the result depends on the variety, harvest date, pretreatment or methodology. For planning, the whole range is useful, not just the average. With a small number of records the deviation is less reliable, so always check the number of records and sources.

Sources: Substraty.pl — kompendium wiedzy o biogazie i biometanie

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