FAQ: Technology and operation

We are not aware of a national provision that would require a separate licence for this. The operator should, however, complete training in operating the OGI camera and interpreting the image, and in explosion-hazard zones use equipment and procedures consistent with the facility's safety rules. In the USA, the EPA Appendix K protocol explicitly describes training requirements for operators.

Sources: Rozporządzenie (UE) 2024/1787 w sprawie redukcji emisji metanu w sektorze energetycznym — EUR-Lex; Jobert et al., Optical Gas Imaging with Cooled and Uncooled Thermal Infrared Cameras, Sensors 2026; Li et al., Chemical Gas Telemetry System Based on Multispectral Infrared Imaging, Toxics 2023; Hagen, Real-Time Quantification of Gas Leaks Using a Snapshot Infrared Spectral Imager, Sensors 2025; Ravikumar, Wang, Brandt, Are Optical Gas Imaging Technologies Effective For Methane Leak Detection?, Environ. Sci. Technol. 2017; Ravikumar et al., „Good versus Good Enough?” Empirical Tests of Methane Leak Detection Sensitivity of a Commercial Infrared Camera, Environ. Sci. Technol. 2018; Ilonze, Wang, Ravikumar, Zimmerle, Methane Quantification Performance of the Quantitative Optical Gas Imaging (QOGI) System Using Single-Blind Controlled Release Assessment, Sensors 2024; Scheutz, Fredenslund, Total methane emission rates and losses from 23 biogas plants, Waste Management 2019; Baldé, Wagner-Riddle, MacDonald, VanderZaag, Fugitive methane emissions from two agricultural biogas plants, Waste Management 2022; Reinelt, Liebetrau, Nelles, Analysis of operational methane emissions from pressure relief valves from biogas storages of biogas plants, Bioresource Technology 2016; Decyzja wykonawcza Komisji 2014/738/UE — konkluzje BAT dla rafinacji ropy naftowej i gazu — EUR-Lex; Dyrektywa (UE) 2018/2001 (RED II), załącznik VI — EUR-Lex; US EPA, NSPS OOOOb i EG OOOOc — Federal Register, 8 marca 2024; US EPA, Appendix K do 40 CFR Part 60 (OGI) — eCFR; EN 17628:2022 — Fugitive and diffuse emissions of common concern to industry sectors: standard method to determine diffuse emissions of VOCs into the atmosphere (katalog SIS); ISO 18436-7:2014 — kwalifikacje personelu termografii; IPCC AR6 WG1, rozdział 7, tab. 7.15 (GWP-100 metanu: 29,8 ± 11 dla pochodzenia kopalnego, 27,0 ± 11 dla niekopalnego); Gordon et al., The HITRAN2020 molecular spectroscopic database, J. Quant. Spectrosc. Radiat. Transf. 2022

Discussed in the article: Optical gas imaging (OGI): a guide for biogas plants, biomethane plants and landfills

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The inhibition threshold depends on the adaptation of the biomass, temperature and pH, and inhibition usually begins at ammonium nitrogen concentrations in the order of several g/l, with the undissociated form (NH₃) being the main toxic one.

A higher temperature and pH increase the share of free ammonia. Microorganisms adapt to higher concentrations, which is why digesters with poultry or protein waste operate stably at values that would cause a failure in other plants. The result is a fall in production and a rise in acids. Remedies: reducing the share of nitrogen-rich substrates, dilution, lowering the temperature, adding carbon-rich substrates.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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No. The cable supplies heat equal to the losses, and without insulation the losses are several times greater, so the required power rises and in strong wind may turn out to be insufficient.

Sources: Dyrektywa 2014/34/UE (ATEX — urządzenia w przestrzeniach zagrożonych wybuchem) — EUR-Lex

Discussed in the article: Will a heating cable protect the system from frost?

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Usually too late. The buffer masks the build-up of acids, so pH falls only at the end. Earlier, FOS/TAC and propionate rise, and the share of CH₄ in the gas falls.

Sources: Chen Y., Cheng J.J., Creamer K.S. (2008), Inhibition of anaerobic digestion process: A review; FNR — Fachagentur Nachwachsende Rohstoffe

Discussed in the article: Digester acidification: symptoms, causes and a step-by-step action plan

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Cooled cameras have a detector chilled to a low temperature and work in a narrow MWIR band; in manufacturers' offerings these are usually solutions for methane and other hydrocarbons. Uncooled cameras use a microbolometer in the LWIR band and are lighter, but have lower sensitivity; manufacturers describe them for, among others, SF₆, ammonia and refrigerants, and some models also for methane. The specific gases and sensitivity must be checked in the datasheet of the given camera.

Sources: Teledyne FLIR — Optical Gas Imaging (przegląd kategorii); Teledyne FLIR — karta produktu GF77 (dane techniczne, stan na 12.08.2026); Teledyne FLIR — seria G (dane techniczne, certyfikaty, stan na 12.08.2026); Konica Minolta — kamera QOGI (GMP03, GMP02); Konica Minolta — komunikat o kamerze GMP03 (2025); Opgal — rodziny produktów OGI (stan na 12.08.2026); Sensia — opis oferty na stronie firmy CORONA (strona producenta niedostępna automatycznie); Sierra-Olympic Technologies — Ventus OGI (rdzeń OEM); Workswell — GIS-320, ładunek OGI dla dronów

Discussed in the article: OGI solutions: handheld, fixed and drone cameras and QOGI — an overview

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Adding trace elements (Fe, Ni, Co, Se, Mo, W and others) is sometimes necessary when the substrates are poor in them, e.g. in mono-digestion of maize silage, but it is not always needed.

Methanogens require trace amounts of metals for their enzymes to work. Slurry and manure usually supply them. A deficiency shows as a fall in gas production and a build-up of acids despite correct loading. The decision should be supported by analysis of concentrations in the digester and by checking the effectiveness of supplementation; overdosing does not improve the process and may inhibit it or increase costs.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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No. The manufacturers and sellers whose websites we checked do not publish OGI camera prices. Instead of approximations, we give a list of cost components worth asking about: the device, lenses, training, cooler servicing, calibration, software.

Sources: Teledyne FLIR — Optical Gas Imaging (przegląd kategorii); Teledyne FLIR — karta produktu GF77 (dane techniczne, stan na 12.08.2026); Teledyne FLIR — seria G (dane techniczne, certyfikaty, stan na 12.08.2026); Konica Minolta — kamera QOGI (GMP03, GMP02); Konica Minolta — komunikat o kamerze GMP03 (2025); Opgal — rodziny produktów OGI (stan na 12.08.2026); Sensia — opis oferty na stronie firmy CORONA (strona producenta niedostępna automatycznie); Sierra-Olympic Technologies — Ventus OGI (rdzeń OEM); Workswell — GIS-320, ładunek OGI dla dronów

Discussed in the article: OGI solutions: handheld, fixed and drone cameras and QOGI — an overview

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This does not follow directly from Regulation (EU) 2024/1787: Article 1(2) covers the extraction and processing of oil and fossil gas, drilling, transmission and distribution of natural gas, storage, LNG installations and coal mines, and the text does not mention biogas or biomethane. Any obligations may arise from other sources (permits, insurance, contracts). The interpretation in a specific situation should be confirmed with the authority or a legal adviser.

Sources: Rozporządzenie (UE) 2024/1787 w sprawie redukcji emisji metanu w sektorze energetycznym — EUR-Lex; EN 17628:2022 — Standardowa metoda wyznaczania emisji rozproszonych LZO (opis normy); Przegląd zastosowań EN 17628:2022 (Sensors 2025, 25(5), 1561; PubMed Central); Teledyne FLIR — broszura OGI w języku polskim (kurs ITC)

Discussed in the article: Implementing OGI at a plant: purchase, rental or external service

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No, a constant reading may mean a fault or a blocked sensor, so results from measuring devices should be periodically verified by independent measurements.

Fouled pH electrodes, drift of gas sensors or blocked sampling tubes give readings that do not change despite real changes in the process. Good practice is comparing online readings with laboratory measurements, calibration on a schedule and alarm logic that detects "frozen" signals. Data from a single sensor should not decide important actions without verification.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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No. In some studies of mixtures a higher yield than the sum is observed, in others no effect or a decrease. It is therefore worth testing the specific mixture with a BMP test.

Sources: IEA Bioenergy Task 37 — Energy from Biogas (materiały o kofermentacji); Holliger C. et al. (2016), Towards a standardization of biomethane potential tests

Discussed in the article: Co-digestion of substrates: how to increase biogas plant stability and yield

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No. The regulation covers oil, fossil gas, natural gas transmission and distribution, storage, LNG installations and coal mines; the words biogas and biomethane do not appear in its text, nor does it name OGI cameras as the only technology. For biogas plants it is good practice and a requirement arising at most from contracts, financing or permits.

Sources: Rozporządzenie (UE) 2024/1787 w sprawie redukcji emisji metanu w sektorze energetycznym — EUR-Lex; Jobert et al., Optical Gas Imaging with Cooled and Uncooled Thermal Infrared Cameras, Sensors 2026; Li et al., Chemical Gas Telemetry System Based on Multispectral Infrared Imaging, Toxics 2023; Hagen, Real-Time Quantification of Gas Leaks Using a Snapshot Infrared Spectral Imager, Sensors 2025; Ravikumar, Wang, Brandt, Are Optical Gas Imaging Technologies Effective For Methane Leak Detection?, Environ. Sci. Technol. 2017; Ravikumar et al., „Good versus Good Enough?” Empirical Tests of Methane Leak Detection Sensitivity of a Commercial Infrared Camera, Environ. Sci. Technol. 2018; Ilonze, Wang, Ravikumar, Zimmerle, Methane Quantification Performance of the Quantitative Optical Gas Imaging (QOGI) System Using Single-Blind Controlled Release Assessment, Sensors 2024; Scheutz, Fredenslund, Total methane emission rates and losses from 23 biogas plants, Waste Management 2019; Baldé, Wagner-Riddle, MacDonald, VanderZaag, Fugitive methane emissions from two agricultural biogas plants, Waste Management 2022; Reinelt, Liebetrau, Nelles, Analysis of operational methane emissions from pressure relief valves from biogas storages of biogas plants, Bioresource Technology 2016; Decyzja wykonawcza Komisji 2014/738/UE — konkluzje BAT dla rafinacji ropy naftowej i gazu — EUR-Lex; Dyrektywa (UE) 2018/2001 (RED II), załącznik VI — EUR-Lex; US EPA, NSPS OOOOb i EG OOOOc — Federal Register, 8 marca 2024; US EPA, Appendix K do 40 CFR Part 60 (OGI) — eCFR; EN 17628:2022 — Fugitive and diffuse emissions of common concern to industry sectors: standard method to determine diffuse emissions of VOCs into the atmosphere (katalog SIS); ISO 18436-7:2014 — kwalifikacje personelu termografii; IPCC AR6 WG1, rozdział 7, tab. 7.15 (GWP-100 metanu: 29,8 ± 11 dla pochodzenia kopalnego, 27,0 ± 11 dla niekopalnego); Gordon et al., The HITRAN2020 molecular spectroscopic database, J. Quant. Spectrosc. Radiat. Transf. 2022

Discussed in the article: Optical gas imaging (OGI): a guide for biogas plants, biomethane plants and landfills

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No, a larger amount of biogas does not always mean more energy, because when the methane share falls, the gas volume may rise while the amount of energy falls.

Energy is determined by the product of biogas volume and methane content. Overloading a digester can increase the production of CO₂ and hydrogen, reducing the share of CH₄. For this reason operators track methane production (m³ CH₄/d) or energy, not biogas alone. An indicator of process quality is also the yield per unit of VS in the feed, compared with BMP.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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A standard OGI camera shows where a leak is, but does not measure its rate. Quantitative OGI (QOGI) estimates the rate in kg CH₄/h, but in a field study 75% of measurements fell within a range from −67% to +200% relative to the actual value.

Sources: Rozporządzenie (UE) 2024/1787 w sprawie redukcji emisji metanu w sektorze energetycznym — EUR-Lex; Jobert et al., Optical Gas Imaging with Cooled and Uncooled Thermal Infrared Cameras, Sensors 2026; Li et al., Chemical Gas Telemetry System Based on Multispectral Infrared Imaging, Toxics 2023; Hagen, Real-Time Quantification of Gas Leaks Using a Snapshot Infrared Spectral Imager, Sensors 2025; Ravikumar, Wang, Brandt, Are Optical Gas Imaging Technologies Effective For Methane Leak Detection?, Environ. Sci. Technol. 2017; Ravikumar et al., „Good versus Good Enough?” Empirical Tests of Methane Leak Detection Sensitivity of a Commercial Infrared Camera, Environ. Sci. Technol. 2018; Ilonze, Wang, Ravikumar, Zimmerle, Methane Quantification Performance of the Quantitative Optical Gas Imaging (QOGI) System Using Single-Blind Controlled Release Assessment, Sensors 2024; Scheutz, Fredenslund, Total methane emission rates and losses from 23 biogas plants, Waste Management 2019; Baldé, Wagner-Riddle, MacDonald, VanderZaag, Fugitive methane emissions from two agricultural biogas plants, Waste Management 2022; Reinelt, Liebetrau, Nelles, Analysis of operational methane emissions from pressure relief valves from biogas storages of biogas plants, Bioresource Technology 2016; Decyzja wykonawcza Komisji 2014/738/UE — konkluzje BAT dla rafinacji ropy naftowej i gazu — EUR-Lex; Dyrektywa (UE) 2018/2001 (RED II), załącznik VI — EUR-Lex; US EPA, NSPS OOOOb i EG OOOOc — Federal Register, 8 marca 2024; US EPA, Appendix K do 40 CFR Part 60 (OGI) — eCFR; EN 17628:2022 — Fugitive and diffuse emissions of common concern to industry sectors: standard method to determine diffuse emissions of VOCs into the atmosphere (katalog SIS); ISO 18436-7:2014 — kwalifikacje personelu termografii; IPCC AR6 WG1, rozdział 7, tab. 7.15 (GWP-100 metanu: 29,8 ± 11 dla pochodzenia kopalnego, 27,0 ± 11 dla niekopalnego); Gordon et al., The HITRAN2020 molecular spectroscopic database, J. Quant. Spectrosc. Radiat. Transf. 2022

Discussed in the article: Optical gas imaging (OGI): a guide for biogas plants, biomethane plants and landfills

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No, it complements them. OGI quickly scans many points and shows a leak from a distance, while a portable detector or EPA Method 21 (sniffing) measures the concentration at the source and helps confirm the repair.

Sources: Rozporządzenie (UE) 2024/1787 w sprawie redukcji emisji metanu w sektorze energetycznym — EUR-Lex; Jobert et al., Optical Gas Imaging with Cooled and Uncooled Thermal Infrared Cameras, Sensors 2026; Li et al., Chemical Gas Telemetry System Based on Multispectral Infrared Imaging, Toxics 2023; Hagen, Real-Time Quantification of Gas Leaks Using a Snapshot Infrared Spectral Imager, Sensors 2025; Ravikumar, Wang, Brandt, Are Optical Gas Imaging Technologies Effective For Methane Leak Detection?, Environ. Sci. Technol. 2017; Ravikumar et al., „Good versus Good Enough?” Empirical Tests of Methane Leak Detection Sensitivity of a Commercial Infrared Camera, Environ. Sci. Technol. 2018; Ilonze, Wang, Ravikumar, Zimmerle, Methane Quantification Performance of the Quantitative Optical Gas Imaging (QOGI) System Using Single-Blind Controlled Release Assessment, Sensors 2024; Scheutz, Fredenslund, Total methane emission rates and losses from 23 biogas plants, Waste Management 2019; Baldé, Wagner-Riddle, MacDonald, VanderZaag, Fugitive methane emissions from two agricultural biogas plants, Waste Management 2022; Reinelt, Liebetrau, Nelles, Analysis of operational methane emissions from pressure relief valves from biogas storages of biogas plants, Bioresource Technology 2016; Decyzja wykonawcza Komisji 2014/738/UE — konkluzje BAT dla rafinacji ropy naftowej i gazu — EUR-Lex; Dyrektywa (UE) 2018/2001 (RED II), załącznik VI — EUR-Lex; US EPA, NSPS OOOOb i EG OOOOc — Federal Register, 8 marca 2024; US EPA, Appendix K do 40 CFR Part 60 (OGI) — eCFR; EN 17628:2022 — Fugitive and diffuse emissions of common concern to industry sectors: standard method to determine diffuse emissions of VOCs into the atmosphere (katalog SIS); ISO 18436-7:2014 — kwalifikacje personelu termografii; IPCC AR6 WG1, rozdział 7, tab. 7.15 (GWP-100 metanu: 29,8 ± 11 dla pochodzenia kopalnego, 27,0 ± 11 dla niekopalnego); Gordon et al., The HITRAN2020 molecular spectroscopic database, J. Quant. Spectrosc. Radiat. Transf. 2022

Discussed in the article: Optical gas imaging (OGI): a guide for biogas plants, biomethane plants and landfills

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No, mixing that is too intensive can break up aggregates of microorganisms, disturb the cooperation of bacteria and methanogens and increase energy consumption; what counts is uniformity, not power.

The aim of mixing is to even out the temperature, distribute the substrate and prevent sediments or scum. Different designs (propeller, slow-speed, hydraulic, gas mixers) consume different amounts of energy. Optimal is intermittent mixing or mixing of variable intensity, adjusted to the TS content. Wearing agitators and seals require scheduled servicing.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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Not automatically. The regulation requires specific parameters for every batch of material and an approved system. Running fermentation at 52–55 °C alone is usually not enough to demonstrate compliance without additional arrangements with the veterinary authority.

Sources: Rozporządzenie (WE) nr 1069/2009 — EUR-Lex; Rozporządzenie (UE) nr 142/2011 — EUR-Lex

Discussed in the article: Hygienisation at 70 °C for 1 hour: animal by-products (ABP) in a biogas plant step by step

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The Regulation entered into force on the twentieth day after publication on 15/07/2024, that is 4/08/2024. Article 14 requires an LDAR programme by 5/05/2025 (existing sites) and the first type 2 survey by 5/08/2025; new sites are subject to shorter deadlines from the start of operation. This applies to operators within the scope of the Regulation.

Sources: Rozporządzenie (UE) 2024/1787 w sprawie redukcji emisji metanu w sektorze energetycznym — EUR-Lex; EN 17628:2022 — Standardowa metoda wyznaczania emisji rozproszonych LZO (opis normy); Przegląd zastosowań EN 17628:2022 (Sensors 2025, 25(5), 1561; PubMed Central); Teledyne FLIR — broszura OGI w języku polskim (kurs ITC)

Discussed in the article: Implementing OGI at a plant: purchase, rental or external service

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A geomembrane biodigester is a prefabricated plastic sleeve, buried or placed in a trench; it is quicker to install than a brick dome, but more sensitive to mechanical damage and UV. A brick dome is durable, but requires a skilled bricklayer and a longer construction time.

Sources: Sistema.bio Kenya — strona firmy (aktualizacja); Biodigester technology firm expands to create climate-smart energy solutions — The Standard (Kenia, 7.08.2024) (aktualizacja); Blazing the blue biogas flame: 15 counties, three countries and counting — Sistema.bio

Discussed in the article: Sistema.bio in Kenya: modular geomembrane biodigesters as an alternative to masonry domes

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OLR describes how much organic matter the digester receives, and HRT how long the liquid stays in it. Both depend on the size of the feed dose, but they are separate parameters and both must be controlled.

Sources: Weiland P. (2010), Biogas production: current state and perspectives; FNR — Fachagentur Nachwachsende Rohstoffe

Discussed in the article: OLR: loading the digester with organic load — how to calculate and choose

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Start-up of a digester consists of filling it with inoculum (e.g. digestate from a working plant), heating it to the working temperature and gradually increasing the substrate loading.

The start-up phase usually lasts from a few weeks to a few months, depending on the substrates and the size of the tank. Increasing the loading too quickly is the most common cause of problems. At the beginning the gas produced may contain little methane and has to be burned in the flare. Start-up requires constant monitoring of pH, acids and gas composition and keeping documentation.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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FOS/TAC is measured by titrating a digester sample with sulphuric acid to specified pH values, and TAC and FOS are calculated from the volume of acid used.

The sample must be centrifuged or filtered and then titrated to pH 5.0 (TAC), then to pH 4.4 (FOS). Methods differ in detail (Nordmann, Kapp), which affects the results, so compare measurements only within a single method. The frequency of measurement depends on the stability of the plant — every few days in new processes or when the recipe changes, and once a week in stabilised ones.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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Moisture is removed by cooling the gas below the dew point (e.g. to 5°C), condensing the vapour on a heat exchanger and reheating the gas before it enters the engine.

The gas cooler is often combined with a condensate separator. An alternative is adsorbents (e.g. silica gel). Effective drying protects against corrosion and ensures a constant calorific value. The efficiency of the system depends on temperature and pressure, and a failure of the cooler results in condensation inside the engine. It is worth monitoring the gas temperature and the condition of the drains.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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Before digestion, waste goes through unpacking, size reduction, separation of contaminants (metals, plastic, glass, stones) and mixing with water or slurry.

The preparation line usually includes a hopper, a shredder, screens, magnetic separators and a hydrocyclone. Packaged waste requires depackagers. Mineral contaminants and plastics cause wear of pumps and agitators and sedimentation. The better the cleaning, the cleaner the digestate. The digester does not remove fragments of plastics and glass — they remain in the digestate.

Sources: Dyrektywa 2008/98/WE w sprawie odpadów — EUR-Lex

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Regulation 2024/1787 requires the operators it covers to keep a register of detected leaks for at least 10 years (Article 14(13)). For other plants, it is good practice to adopt a similar period.

Sources: Rozporządzenie (UE) 2024/1787 w sprawie redukcji emisji metanu w sektorze energetycznym — EUR-Lex; EN 17628:2022 — Standardowa metoda wyznaczania emisji rozproszonych LZO (opis normy); Przegląd zastosowań EN 17628:2022 (Sensors 2025, 25(5), 1561; PubMed Central); Teledyne FLIR — broszura OGI w języku polskim (kurs ITC)

Discussed in the article: Implementing OGI at a plant: purchase, rental or external service

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It depends on the share of slurry and on the yield. In the example from the article (a mix with approx. 15,000 t of slurry a year, yield 45 t/ha) this comes to approx. 190 ha after allowing for losses (approx. 210 ha with a 10% reserve for a poorer yield), but with a higher share of silage it can be several hundred hectares.

Sources: FNR — Fachagentur Nachwachsende Rohstoffe; KTBL — Kuratorium für Technik und Bauwesen in der Landwirtschaft

Discussed in the article: Planning substrate demand: the annual balance and area of cropland

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The more often and in the smaller portions, the better for the process. In practice, from a dozen or so to several dozen doses per day are used, controlled by time or by weight, to avoid load peaks.

Sources: FNR — Fachagentur Nachwachsende Rohstoffe (Leitfaden Biogas); KTBL — Kuratorium für Technik und Bauwesen in der Landwirtschaft

Discussed in the article: Solid substrate feeders in a biogas plant: types, selection and operation

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Stoichiometrically very little (a fraction of a per cent of the gas volume), in practice usually from a fraction of a per cent to a few per cent, depending on the H₂S load and the effectiveness of contact. The dose is selected by measuring oxygen and H₂S in the gas, not as a fixed value.

Sources: FNR — Fachagentur Nachwachsende Rohstoffe (Leitfaden Biogas); IEA Bioenergy Task 37; Dyrektywa 1999/92/WE (ATEX 137) — EUR-Lex

Discussed in the article: Biological biogas desulphurisation: air dose, bacteria and risks

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It depends on the scale of the installation. In an example biogas plant (illustrative assumptions, 2.2 million m³ CH₄ a year) every 1% loss of the methane produced is approx. 22,000 m³, that is, about 219 MWh of energy and approx. 428 t CO₂e a year. The real value is calculated from your own data and your own energy price.

Sources: Rozporządzenie (UE) 2024/1787 w sprawie redukcji emisji metanu w sektorze energetycznym — EUR-Lex; Jobert et al., Optical Gas Imaging with Cooled and Uncooled Thermal Infrared Cameras, Sensors 2026; Li et al., Chemical Gas Telemetry System Based on Multispectral Infrared Imaging, Toxics 2023; Hagen, Real-Time Quantification of Gas Leaks Using a Snapshot Infrared Spectral Imager, Sensors 2025; Ravikumar, Wang, Brandt, Are Optical Gas Imaging Technologies Effective For Methane Leak Detection?, Environ. Sci. Technol. 2017; Ravikumar et al., „Good versus Good Enough?” Empirical Tests of Methane Leak Detection Sensitivity of a Commercial Infrared Camera, Environ. Sci. Technol. 2018; Ilonze, Wang, Ravikumar, Zimmerle, Methane Quantification Performance of the Quantitative Optical Gas Imaging (QOGI) System Using Single-Blind Controlled Release Assessment, Sensors 2024; Scheutz, Fredenslund, Total methane emission rates and losses from 23 biogas plants, Waste Management 2019; Baldé, Wagner-Riddle, MacDonald, VanderZaag, Fugitive methane emissions from two agricultural biogas plants, Waste Management 2022; Reinelt, Liebetrau, Nelles, Analysis of operational methane emissions from pressure relief valves from biogas storages of biogas plants, Bioresource Technology 2016; Decyzja wykonawcza Komisji 2014/738/UE — konkluzje BAT dla rafinacji ropy naftowej i gazu — EUR-Lex; Dyrektywa (UE) 2018/2001 (RED II), załącznik VI — EUR-Lex; US EPA, NSPS OOOOb i EG OOOOc — Federal Register, 8 marca 2024; US EPA, Appendix K do 40 CFR Part 60 (OGI) — eCFR; EN 17628:2022 — Fugitive and diffuse emissions of common concern to industry sectors: standard method to determine diffuse emissions of VOCs into the atmosphere (katalog SIS); ISO 18436-7:2014 — kwalifikacje personelu termografii; IPCC AR6 WG1, rozdział 7, tab. 7.15 (GWP-100 metanu: 29,8 ± 11 dla pochodzenia kopalnego, 27,0 ± 11 dla niekopalnego); Gordon et al., The HITRAN2020 molecular spectroscopic database, J. Quant. Spectrosc. Radiat. Transf. 2022

Discussed in the article: Optical gas imaging (OGI): a guide for biogas plants, biomethane plants and landfills

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At 52% CH₄, biogas has approx. 5.2 kWh/m³ of chemical energy; at an electrical efficiency of 40% that is approx. 2.1 kWh of electricity and a similar or larger amount of heat.

Sources: FNR — Fachagentur Nachwachsende Rohstoffe; IEA Bioenergy Task 37; Weiland P. (2010), Biogas production: current state and perspectives

Discussed in the article: The CHP engine at a biogas plant: electrical and thermal efficiency and part-load operation

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Values in the literature vary widely, from a fraction of a per cent to several per cent of production, depending on the design, the covering of the digestate and the quality of operation. The best answer is a measurement at your own plant.

Sources: Rozporządzenie (UE) 2024/1787 w sprawie redukcji emisji metanu w sektorze energetycznym — EUR-Lex; IEA Bioenergy Task 37; European Biogas Association

Discussed in the article: Methane losses and fugitive emissions at a biogas plant: detection and reduction

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Under Article 14(9) of Regulation 2024/1787: repair immediately after detection, and if that is not possible, an attempt no later than within 5 days and completion within 30 days, with exceptions and a reporting obligation. For installations outside the scope of the Regulation, it is good practice to set your own deadlines in the procedure.

Sources: Rozporządzenie (UE) 2024/1787 w sprawie redukcji emisji metanu w sektorze energetycznym — EUR-Lex; EN 17628:2022 — Standardowa metoda wyznaczania emisji rozproszonych LZO (opis normy); Przegląd zastosowań EN 17628:2022 (Sensors 2025, 25(5), 1561; PubMed Central); Teledyne FLIR — broszura OGI w języku polskim (kurs ITC)

Discussed in the article: Implementing OGI at a plant: purchase, rental or external service

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A cogeneration engine requires inspections at set intervals depending on the manufacturer, usually counted in operating hours (from several hundred to over ten thousand, depending on the scope).

Routine tasks are changing oil and filters, checking spark plugs, valves and the cooling system, and after a longer time — major overhauls. Biogas quality (H₂S, siloxanes, moisture) strongly affects wear. Oil analyses make it possible to predict problems. The service plan should follow the manufacturer's manual, not general experience, and be taken into account in the availability calculation.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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No EU rule sets a frequency for biogas plants. The editorial team's recommendation (not a requirement): a reasonable starting point is a survey of the whole installation once a year, an additional check after major overhauls and a quick verification after failures; for gas stations connected to the grid, however, the intervals from Regulation 2024/1787 apply (e.g. every 4 months for a type 1 survey or every 8 months for type 2 at pressure regulating and metering stations; details and exceptions in Annex I).

Sources: Rozporządzenie (UE) 2024/1787 w sprawie redukcji emisji metanu w sektorze energetycznym — EUR-Lex; Jobert et al., Optical Gas Imaging with Cooled and Uncooled Thermal Infrared Cameras, Sensors 2026; Li et al., Chemical Gas Telemetry System Based on Multispectral Infrared Imaging, Toxics 2023; Hagen, Real-Time Quantification of Gas Leaks Using a Snapshot Infrared Spectral Imager, Sensors 2025; Ravikumar, Wang, Brandt, Are Optical Gas Imaging Technologies Effective For Methane Leak Detection?, Environ. Sci. Technol. 2017; Ravikumar et al., „Good versus Good Enough?” Empirical Tests of Methane Leak Detection Sensitivity of a Commercial Infrared Camera, Environ. Sci. Technol. 2018; Ilonze, Wang, Ravikumar, Zimmerle, Methane Quantification Performance of the Quantitative Optical Gas Imaging (QOGI) System Using Single-Blind Controlled Release Assessment, Sensors 2024; Scheutz, Fredenslund, Total methane emission rates and losses from 23 biogas plants, Waste Management 2019; Baldé, Wagner-Riddle, MacDonald, VanderZaag, Fugitive methane emissions from two agricultural biogas plants, Waste Management 2022; Reinelt, Liebetrau, Nelles, Analysis of operational methane emissions from pressure relief valves from biogas storages of biogas plants, Bioresource Technology 2016; Decyzja wykonawcza Komisji 2014/738/UE — konkluzje BAT dla rafinacji ropy naftowej i gazu — EUR-Lex; Dyrektywa (UE) 2018/2001 (RED II), załącznik VI — EUR-Lex; US EPA, NSPS OOOOb i EG OOOOc — Federal Register, 8 marca 2024; US EPA, Appendix K do 40 CFR Part 60 (OGI) — eCFR; EN 17628:2022 — Fugitive and diffuse emissions of common concern to industry sectors: standard method to determine diffuse emissions of VOCs into the atmosphere (katalog SIS); ISO 18436-7:2014 — kwalifikacje personelu termografii; IPCC AR6 WG1, rozdział 7, tab. 7.15 (GWP-100 metanu: 29,8 ± 11 dla pochodzenia kopalnego, 27,0 ± 11 dla niekopalnego); Gordon et al., The HITRAN2020 molecular spectroscopic database, J. Quant. Spectrosc. Radiat. Transf. 2022

Discussed in the article: Optical gas imaging (OGI): a guide for biogas plants, biomethane plants and landfills

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Foaming must be reacted to immediately after the first signs are noticed — a rise of foam in the digester or in the gas system — because it can lead to flooding of the gas installation and an interruption of engine operation.

First steps: limit or stop dosing substrates suspected of foaming (fats, proteins, sugar), and check mixing, temperature and FOS/TAC. If necessary, antifoaming agents are used, but their use is a stopgap measure. The cause must be established: overload, a change of recipe, too intensive mixing, sudden temperature changes. It is worth having an emergency procedure and a stock of antifoam.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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Divide the price of a delivered tonne of fresh matter by the methane yield from that tonne. Yield = TS × VS × BMP (TS and VS as fractions, BMP in m³ CH₄ per kg VS, result per tonne after multiplying by 1000).

Sources: Holliger C. et al. (2016), Towards a standardization of biomethane potential tests; IEA Bioenergy Task 37 — Energy from Biogas

Discussed in the article: How to choose the optimal substrate for a biogas plant? Parameters, mistakes and cost calculation

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Acidification of a digester shows up as a rise in the concentration of volatile acids (FOS/TAC rises), a fall in pH and in the methane content of the gas, a fall in biogas production and an increased amount of CO₂ and hydrogen.

The fall in pH occurs later than the rise in acids, because the mixture has a buffer. The response consists of limiting or stopping substrate dosing, checking the temperature and adding alkalising agents or buffering substances (e.g. calcium or sodium hydroxide – after consulting an adviser). After stabilisation, the loading is increased gradually. A quick reaction shortens the time to return to normal production.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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Entering a digester requires a confined space procedure: switching off power, isolating the gas, ventilation, atmosphere measurements, safeguarding and the presence of a second person outside.

Even after emptying, H₂S, CH₄ and CO₂ may remain in the tank, and the lack of oxygen creates a life-threatening hazard without any warning smell. Before work gas concentrations are measured, and during it they are monitored continuously. The work should be carried out by trained workers with appropriate equipment (breathing apparatus, harnesses). When commissioning servicing from an external company, check its qualifications and procedures.

Sources: Hydrogen Sulfide — OSHA; Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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No, the thermophilic process (approx. 50–55°C) usually runs faster than the mesophilic one (approx. 35–42°C), but it is more sensitive to disturbances and ammonia and requires more heat.

The advantages of thermophilic operation are a shorter retention time, better hygienisation and often higher gas production; the disadvantages are instability and more expensive temperature maintenance. Most agricultural biogas plants operate in the mesophilic range for process safety. A change of temperature requires a gradual transition, because microorganisms must adapt — an abrupt change can inhibit production for weeks.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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The regulation does not name OGI: it requires devices that make it possible to identify a leak as close to the source as possible and refers to thresholds in ppmv and g/h. The operator must provide the authority with information about the device (Annex I, Part 2). OGI alone is usually supplemented with quantitative measurement, and “advanced technologies” (a term from the regulation) require the consent of the competent authority.

In practice the camera is combined with an FID/PID analyser or with a quantification function (QOGI), and with software for recording leaks and repairs.

Sources: Rozporządzenie (UE) 2024/1787 w sprawie redukcji emisji metanu w sektorze energetycznym — EUR-Lex; EN 17628:2022 — Standardowa metoda wyznaczania emisji rozproszonych LZO (opis normy); Przegląd zastosowań EN 17628:2022 (Sensors 2025, 25(5), 1561; PubMed Central); Teledyne FLIR — broszura OGI w języku polskim (kurs ITC); Teledyne FLIR — Optical Gas Imaging (przegląd kategorii); Teledyne FLIR — karta produktu GF77 (dane techniczne, stan na 12.08.2026); Teledyne FLIR — seria G (dane techniczne, certyfikaty, stan na 12.08.2026); Konica Minolta — kamera QOGI (GMP03, GMP02); Konica Minolta — komunikat o kamerze GMP03 (2025); Opgal — rodziny produktów OGI (stan na 12.08.2026); Sensia — opis oferty na stronie firmy CORONA (strona producenta niedostępna automatycznie); Sierra-Olympic Technologies — Ventus OGI (rdzeń OEM); Workswell — GIS-320, ładunek OGI dla dronów

Discussed in the article: Implementing OGI at a plant: purchase, rental or external service, OGI solutions: handheld, fixed and drone cameras and QOGI — an overview

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Usually yes. Full load gives the highest electrical efficiency; operation below about 50–60% of capacity noticeably worsens efficiency and promotes fouling of the engine.

Sources: FNR — Fachagentur Nachwachsende Rohstoffe; IEA Bioenergy Task 37; Weiland P. (2010), Biogas production: current state and perspectives

Discussed in the article: The CHP engine at a biogas plant: electrical and thermal efficiency and part-load operation

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No. The tank must be isolated from the plant, ventilation must be forced, and before entry and during work the concentrations of oxygen, methane, H₂S and CO must be measured (and, if necessary, also CO₂). Sludge on the bottom can release gas when disturbed.

Sources: Państwowa Inspekcja Pracy; Centralny Instytut Ochrony Pracy — PIB (CIOP); Dyrektywa 1999/92/WE (ATEX 137) — EUR-Lex

Discussed in the article: Entering a tank or digester: rules for work in confined spaces

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No, the ATEX marking applies to a specific device, while the safety of the whole facility requires hazard assessment, zoning, an explosion protection document and procedures.

Directive 2014/34/EU sets requirements for equipment, and Directive 1999/92/EC for the protection of workers. A certified device may be used only in the zone for which it is intended, and it must be properly installed and maintained. In addition, training, inspections and control of ignition sources (e.g. static electricity, mechanical sparks) are needed. Servicing work also accounts for a significant part of the risk.

Sources: Dyrektywa 1999/92/WE — ochrona pracowników w atmosferach wybuchowych — EUR-Lex; Dyrektywa 2014/34/UE — urządzenia w atmosferach potencjalnie wybuchowych — EUR-Lex

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No, the safe range of FOS/TAC depends on the substrates, temperature, retention time and process history, so each plant should establish its own working range.

Digesters fed with slurry usually have a low FOS/TAC, and those running on maize monosubstrates may run higher but are less resistant to disturbances. Instead of relying on the absolute value, changes are observed: a sudden rise in FOS or fall in TAC indicates acidification. Equally important are pH, gas composition (CH₄/CO₂) and biogas production per unit of feed.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

Discussed in the article: Optimising the methane fermentation process in agricultural biogas plants

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An ordinary thermal imager measures infrared radiation in a broad band and shows surface temperature. An OGI camera additionally has a spectral filter matched to the absorption band of the selected gas, so it shows not temperature but a gas cloud that absorbs background radiation.

Sources: Rozporządzenie (UE) 2024/1787 w sprawie redukcji emisji metanu w sektorze energetycznym — EUR-Lex; Jobert et al., Optical Gas Imaging with Cooled and Uncooled Thermal Infrared Cameras, Sensors 2026; Li et al., Chemical Gas Telemetry System Based on Multispectral Infrared Imaging, Toxics 2023; Hagen, Real-Time Quantification of Gas Leaks Using a Snapshot Infrared Spectral Imager, Sensors 2025; Ravikumar, Wang, Brandt, Are Optical Gas Imaging Technologies Effective For Methane Leak Detection?, Environ. Sci. Technol. 2017; Ravikumar et al., „Good versus Good Enough?” Empirical Tests of Methane Leak Detection Sensitivity of a Commercial Infrared Camera, Environ. Sci. Technol. 2018; Ilonze, Wang, Ravikumar, Zimmerle, Methane Quantification Performance of the Quantitative Optical Gas Imaging (QOGI) System Using Single-Blind Controlled Release Assessment, Sensors 2024; Scheutz, Fredenslund, Total methane emission rates and losses from 23 biogas plants, Waste Management 2019; Baldé, Wagner-Riddle, MacDonald, VanderZaag, Fugitive methane emissions from two agricultural biogas plants, Waste Management 2022; Reinelt, Liebetrau, Nelles, Analysis of operational methane emissions from pressure relief valves from biogas storages of biogas plants, Bioresource Technology 2016; Decyzja wykonawcza Komisji 2014/738/UE — konkluzje BAT dla rafinacji ropy naftowej i gazu — EUR-Lex; Dyrektywa (UE) 2018/2001 (RED II), załącznik VI — EUR-Lex; US EPA, NSPS OOOOb i EG OOOOc — Federal Register, 8 marca 2024; US EPA, Appendix K do 40 CFR Part 60 (OGI) — eCFR; EN 17628:2022 — Fugitive and diffuse emissions of common concern to industry sectors: standard method to determine diffuse emissions of VOCs into the atmosphere (katalog SIS); ISO 18436-7:2014 — kwalifikacje personelu termografii; IPCC AR6 WG1, rozdział 7, tab. 7.15 (GWP-100 metanu: 29,8 ± 11 dla pochodzenia kopalnego, 27,0 ± 11 dla niekopalnego); Gordon et al., The HITRAN2020 molecular spectroscopic database, J. Quant. Spectrosc. Radiat. Transf. 2022

Discussed in the article: Optical gas imaging (OGI): a guide for biogas plants, biomethane plants and landfills

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Siloxanes are organosilicon compounds (from cosmetics, detergents) that, when burned, form a hard silica deposit on engine components, shortening its service life.

They occur mainly in biogas from wastewater treatment plants and landfills, and to a lesser extent in agricultural biogas. They are removed with activated carbon, cooling or adsorbents. Detection requires laboratory analyses. At high concentrations the cost of replacing the bed significantly affects operation. If the plant processes waste, it is worth including this indicator in gas analyses.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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The optimal carbon-to-nitrogen (C:N) ratio in the feed mixture most often lies in the range of about 20–30:1, but it does not in itself guarantee stable operation.

A C:N that is too low (excess nitrogen) increases the risk of ammonia inhibition, and one that is too high limits the growth of microorganisms. It helps to mix nitrogen-rich substrates (poultry, proteins) with carbon-rich ones (silages, straw). The indicator is approximate, because part of the carbon and nitrogen is not biologically available, so ammonia, pH and FOS/TAC must also be monitored.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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Foaming is most often caused by organic overload, a sudden change of recipe, an excess of fats or proteins, the presence of surfactants, uneven mixing and temperature fluctuations.

Foam forms when gas bubbles are held by particles and surface-active substances. Particularly risky are waste from the food industry (including fats and dairy waste), beet pulp, and contamination with detergents. It is also promoted by acidification and short-term spikes in gas production. Prevention includes gradual recipe changes, even feeding and monitoring of FOS/TAC.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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Explosion hazard zones (0, 1, 2 for gases) classify locations according to the probability of an explosive atmosphere occurring, which determines the requirements for equipment and work.

Zone 0 is a place where an explosive atmosphere is present continuously, frequently or for long periods (e.g. the inside of a gas holder), zone 1 — occasionally in normal operation, zone 2 — rarely and for a short time. The boundaries of zones are set in the explosion protection document on the basis of a risk analysis. Around valves, compressors, sensors and ventilation openings the zones are usually larger. After a modernisation of the plant the classification must be verified.

Sources: Dyrektywa 1999/92/WE — ochrona pracowników w atmosferach wybuchowych — EUR-Lex

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An FOS/TAC of 0.4 means that the ratio of volatile fatty acids (FOS) to buffering capacity (TAC) is 0.4, which in many plants lies at the upper limit of stable operation, but there is no single universal standard.

FOS is most often expressed in mg of acetic acid per litre, and TAC in mg of CaCO₃ per litre (the Nordmann method or similar). Values of 0.2–0.4 are often regarded as typical for stable processes, and above 0.5–0.6 as a signal of acidification risk. More important than a single reading is the trend and the historical values of a given digester. The interpretation should be related to the substrates and temperature.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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OLR (organic loading rate) is the mass of volatile solids (VS) added to the digester per day per unit of its volume, usually in kg VS/(m³·d).

It is calculated by dividing the daily amount of VS in the feed by the working volume of the digester. Typically agricultural biogas plants operate at loadings in the order of several kg VS/(m³·d), and the limits depend on the substrate, temperature and mixing. Too high an OLR leads to acidification, too low to incomplete use of the tank. OLR is changed slowly, and process control should also include FOS/TAC.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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There is no universal threshold. Values above approx. 0.4–0.5 in a plant that usually has 0.25 require a response; in another one, running stably at higher values, a rapid rise matters more.

Sources: FNR — Fachagentur Nachwachsende Rohstoffe; Chen Y., Cheng J.J., Creamer K.S. (2008), Inhibition of anaerobic digestion process: A review

Discussed in the article: FOS/TAC in a biogas plant: how to measure, how to interpret, what not to do

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A biogas plant should have fixed detectors for methane, hydrogen sulphide and oxygen in hazardous locations, and workers in risk zones should carry portable detectors.

The type and placement of sensors result from the explosion risk assessment and the explosion protection document (in line with ATEX requirements). Sensors require periodic calibration and testing (e.g. with calibration gas), because drift causes false readings. Alarms should trigger ventilation and evacuation procedures. Verification of alarms during inspections is crucial.

Sources: Dyrektywa 1999/92/WE — ochrona pracowników w atmosferach wybuchowych — EUR-Lex

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Hydraulic retention time (HRT) is the average time a substrate stays in the digester, calculated as the working volume divided by the daily feed flow rate.

In agricultural biogas plants HRT is often several dozen days (e.g. 40–100), although it depends on the substrates and configuration. Too short a time causes washout of microorganisms and incomplete degradation, too long wastes capacity. The real residence time of particles varies because of imperfect mixing, and increasing HRT is sometimes the simplest way to improve the yield from hard-to-degrade substrates.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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Hygienisation is a heat treatment (e.g. 70 °C for an hour) that destroys pathogens in waste, required when processing, among others, certain animal by-products and biowaste.

The conditions depend on the category of the material (the provisions of Regulation 1069/2009 and implementing acts) and on the method of processing. Hygienisation is usually carried out before or after digestion, in a separate tank (a pasteurisation/hygienisation unit). The operation of the digester at mesophilic temperature does not replace it; however, the competent authority may approve parameters other than the standard ones if it has been shown that they ensure an adequate reduction of biological risk. Documentation of temperature and time and microbiological control are required.

Sources: Rozporządzenie (WE) nr 1069/2009 — uboczne produkty pochodzenia zwierzęcego — EUR-Lex

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The degree of degradation is the percentage of VS in the feed that has been converted into biogas, and it describes how effectively the digester uses the substrate.

It is calculated from a VS balance or by comparing the methane yield with BMP. A low degree of degradation means energy losses and greater emissions from the digestate (further release of methane in the tank). It is improved by a longer retention time, better mixing, an additional digester or pretreatment. Values depend on the substrate, and incomplete degradation is also sometimes a source of problems in the digestate tank.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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A biogas analyser usually measures CH₄, CO₂, O₂ and H₂S, and in some models also H₂ and NH₃, which makes it possible to assess gas quality and process stability.

A fall in the methane share with a rise in CO₂ signals problems in the digester, and rising oxygen — a leak or excessive dosing of air for desulphurisation. Sensors require calibration with calibration gases, and sample conditions (moisture, temperature) affect the readings. The trend of readings is more important than a single result. Analysers should raise alarms and log data.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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For methane fermentation the optimum pH is approximately 6.8 to 8, and in typical agricultural biogas plants usually 7.2–8.0.

Methanogens are sensitive to acidification, but pH changes with a delay relative to disturbances, because the mixture has buffering capacity. For this reason pH alone is a poor early-warning indicator — FOS/TAC and gas composition react faster. A high pH (above 8) with a high ammonium nitrogen content increases the share of toxic free ammonia. pH measurements require regular calibration of the electrode.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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It is worth monitoring temperature, pH, FOS/TAC, gas quantity and composition, substrate dosing, level and mixing, and basic analyses of the digestate (TS, VS, ammonium nitrogen).

Data from online sensors are supplemented by laboratory tests: ammonium nitrogen, fatty acids, trace elements, TS and VS. Changes in trends make it possible to detect a problem early. Operating records are also the basis for diagnostics in the event of failures and documentation for the authorities. The frequency of tests depends on the stability of the plant and the contract with the laboratory or service provider.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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Hydrogen sulphide and moisture in the gas, operation at low load, infrequent oil changes and neglected cooling. Good desulphurisation and gas drying are the cheapest way to ensure engine durability.

Sources: FNR — Fachagentur Nachwachsende Rohstoffe; KTBL — Kuratorium für Technik und Bauwesen in der Landwirtschaft

Discussed in the article: Servicing a CHP gas engine: oil, spark plugs, valves and major overhauls

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Scum (a floating layer) and bottom sediment reduce the effective volume of the digester and hinder mixing, so they require monitoring and, where necessary, removal or a change of the mixing arrangement.

Scum is formed by fibrous, light fractions, e.g. straw or plant residues, and sediment by sand, stones and mineral particles from silage or manure. They are prevented by proper preparation of substrates (grinding, sand removal) and effective mixing. Periodic cleaning of tanks involves hazards (lack of oxygen, gases), and the work is carried out according to confined space entry procedures.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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When the temperature difference between the gas and the background is too small, in strong wind that dilutes the plume, at a large distance, against a complex background (vegetation, shiny surfaces) and with very small leaks. In tests of one commercial camera, the median detectability (50%) was approx. 20 g CH₄/h from a distance of 6 m.

Sources: Rozporządzenie (UE) 2024/1787 w sprawie redukcji emisji metanu w sektorze energetycznym — EUR-Lex; Jobert et al., Optical Gas Imaging with Cooled and Uncooled Thermal Infrared Cameras, Sensors 2026; Li et al., Chemical Gas Telemetry System Based on Multispectral Infrared Imaging, Toxics 2023; Hagen, Real-Time Quantification of Gas Leaks Using a Snapshot Infrared Spectral Imager, Sensors 2025; Ravikumar, Wang, Brandt, Are Optical Gas Imaging Technologies Effective For Methane Leak Detection?, Environ. Sci. Technol. 2017; Ravikumar et al., „Good versus Good Enough?” Empirical Tests of Methane Leak Detection Sensitivity of a Commercial Infrared Camera, Environ. Sci. Technol. 2018; Ilonze, Wang, Ravikumar, Zimmerle, Methane Quantification Performance of the Quantitative Optical Gas Imaging (QOGI) System Using Single-Blind Controlled Release Assessment, Sensors 2024; Scheutz, Fredenslund, Total methane emission rates and losses from 23 biogas plants, Waste Management 2019; Baldé, Wagner-Riddle, MacDonald, VanderZaag, Fugitive methane emissions from two agricultural biogas plants, Waste Management 2022; Reinelt, Liebetrau, Nelles, Analysis of operational methane emissions from pressure relief valves from biogas storages of biogas plants, Bioresource Technology 2016; Decyzja wykonawcza Komisji 2014/738/UE — konkluzje BAT dla rafinacji ropy naftowej i gazu — EUR-Lex; Dyrektywa (UE) 2018/2001 (RED II), załącznik VI — EUR-Lex; US EPA, NSPS OOOOb i EG OOOOc — Federal Register, 8 marca 2024; US EPA, Appendix K do 40 CFR Part 60 (OGI) — eCFR; EN 17628:2022 — Fugitive and diffuse emissions of common concern to industry sectors: standard method to determine diffuse emissions of VOCs into the atmosphere (katalog SIS); ISO 18436-7:2014 — kwalifikacje personelu termografii; IPCC AR6 WG1, rozdział 7, tab. 7.15 (GWP-100 metanu: 29,8 ± 11 dla pochodzenia kopalnego, 27,0 ± 11 dla niekopalnego); Gordon et al., The HITRAN2020 molecular spectroscopic database, J. Quant. Spectrosc. Radiat. Transf. 2022

Discussed in the article: Optical gas imaging (OGI): a guide for biogas plants, biomethane plants and landfills

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The operator as employer: assesses the risk, classifies the zones, selects the equipment and maintains the explosion protection document. The manufacturer is responsible for the conformity of the equipment with the requirements of Directive 2014/34/EU.

Sources: Dyrektywa 1999/92/WE (ATEX 137) — EUR-Lex; Dyrektywa 2014/34/UE (ATEX 114) — EUR-Lex; Państwowa Inspekcja Pracy

Discussed in the article: ATEX at a biogas plant: directives, obligations and the explosion protection document

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Toxicity depends on the concentration of free ammonia (NH₃), which depends on pH and temperature, and not only on the total ammonium nitrogen content (NH₄⁺ + NH₃).

In the same sample, free ammonia can be several times higher at 55°C than at 37°C and at pH 8.0 than at 7.2. To assess the risk, the share of NH₃ is calculated from the chemical equilibrium. In addition, biomass adapted to nitrogen tolerates higher concentrations. For this reason the assessment should combine analysis of nitrogen, pH, temperature and gas production data.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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Biogas is saturated with water vapour, which condenses in the pipes and collects at low points, and accumulated condensate blocks flow and causes corrosion.

Pipes are laid with a slope towards drains (traps), which must be checked regularly, especially in winter when they freeze. In addition, cooling the gas before the engine removes moisture and part of the contaminants. Condensate contains acidic compounds and ammonia, so it requires proper disposal. A blocked pipe can disrupt engine operation or cause a rise in pressure.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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For work in explosive atmosphere zones, and the areas around biogas tanks and upgrading installations can be such a zone. The Ex version is certified for a specific category and gas group; the scope of certification differs between models, so the marking on the nameplate and in the declaration of conformity must always be checked.

Sources: Teledyne FLIR — Optical Gas Imaging (przegląd kategorii); Teledyne FLIR — karta produktu GF77 (dane techniczne, stan na 12.08.2026); Teledyne FLIR — seria G (dane techniczne, certyfikaty, stan na 12.08.2026); Konica Minolta — kamera QOGI (GMP03, GMP02); Konica Minolta — komunikat o kamerze GMP03 (2025); Opgal — rodziny produktów OGI (stan na 12.08.2026); Sensia — opis oferty na stronie firmy CORONA (strona producenta niedostępna automatycznie); Sierra-Olympic Technologies — Ventus OGI (rdzeń OEM); Workswell — GIS-320, ładunek OGI dla dronów

Discussed in the article: OGI solutions: handheld, fixed and drone cameras and QOGI — an overview

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Regular, even dosing of feed maintains constant conditions for microorganisms and prevents sudden fluctuations in volatile acids, pH and gas production.

Large, infrequent doses cause a rapid rise in acids and temporary inhibition of methanogenesis. Good practice is dosing several times a day, preferably automatically, with weighing. Recipe changes are introduced gradually — over days or weeks — so that microorganisms can adapt. In the event of a feeder failure, after a break the loading is restored step by step.

The same daily mass of feed can produce a different biological response depending on how the doses are spread over time, and the daily average does not reveal such a pulse.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR; AgSTAR Operator Guidebook — US EPA (listopad 2020)

Discussed in the article: Biogas plant feeding stability: why the daily total of feed is not enough

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A post-digestion tank (secondary digester) extends the residence time of the substrate and allows additional biogas to be recovered that would otherwise be released in the digestate tank.

It is usually a tank with an agitator and a gas roof, connected in series with the main digester. It increases methane yield by a few per cent up to a dozen or so, but requires additional investment and insulation. It also reduces emissions from digestate storage. Profitability depends on the type of substrate and the retention time in the main digester.

Sources: Anaerobic Digester/Biogas System Operator Guidebook — US EPA AgSTAR

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No. Only a gas that absorbs infrared in the camera's band is visible. Methane and other hydrocarbons can be seen with cameras tuned to the 3.2–3.55 µm band, whereas hydrogen, nitrogen and oxygen do not form an image at all. Hydrogen sulphide is usually detected with sensors, not with a camera.

Sources: Rozporządzenie (UE) 2024/1787 w sprawie redukcji emisji metanu w sektorze energetycznym — EUR-Lex; Jobert et al., Optical Gas Imaging with Cooled and Uncooled Thermal Infrared Cameras, Sensors 2026; Li et al., Chemical Gas Telemetry System Based on Multispectral Infrared Imaging, Toxics 2023; Hagen, Real-Time Quantification of Gas Leaks Using a Snapshot Infrared Spectral Imager, Sensors 2025; Ravikumar, Wang, Brandt, Are Optical Gas Imaging Technologies Effective For Methane Leak Detection?, Environ. Sci. Technol. 2017; Ravikumar et al., „Good versus Good Enough?” Empirical Tests of Methane Leak Detection Sensitivity of a Commercial Infrared Camera, Environ. Sci. Technol. 2018; Ilonze, Wang, Ravikumar, Zimmerle, Methane Quantification Performance of the Quantitative Optical Gas Imaging (QOGI) System Using Single-Blind Controlled Release Assessment, Sensors 2024; Scheutz, Fredenslund, Total methane emission rates and losses from 23 biogas plants, Waste Management 2019; Baldé, Wagner-Riddle, MacDonald, VanderZaag, Fugitive methane emissions from two agricultural biogas plants, Waste Management 2022; Reinelt, Liebetrau, Nelles, Analysis of operational methane emissions from pressure relief valves from biogas storages of biogas plants, Bioresource Technology 2016; Decyzja wykonawcza Komisji 2014/738/UE — konkluzje BAT dla rafinacji ropy naftowej i gazu — EUR-Lex; Dyrektywa (UE) 2018/2001 (RED II), załącznik VI — EUR-Lex; US EPA, NSPS OOOOb i EG OOOOc — Federal Register, 8 marca 2024; US EPA, Appendix K do 40 CFR Part 60 (OGI) — eCFR; EN 17628:2022 — Fugitive and diffuse emissions of common concern to industry sectors: standard method to determine diffuse emissions of VOCs into the atmosphere (katalog SIS); ISO 18436-7:2014 — kwalifikacje personelu termografii; IPCC AR6 WG1, rozdział 7, tab. 7.15 (GWP-100 metanu: 29,8 ± 11 dla pochodzenia kopalnego, 27,0 ± 11 dla niekopalnego); Gordon et al., The HITRAN2020 molecular spectroscopic database, J. Quant. Spectrosc. Radiat. Transf. 2022

Discussed in the article: Optical gas imaging (OGI): a guide for biogas plants, biomethane plants and landfills

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Some manufacturers describe such models: for example, FLIR states that the GF77 with a lens in the 7–8.5 µm band detects, among others, methane and propane. The sensitivity of such cameras is, however, different from that of cooled cameras, so suitability for a given task (e.g. small leaks at a biogas plant) should be checked in the technical data and, ideally, in a field trial.

Sources: Teledyne FLIR — Optical Gas Imaging (przegląd kategorii); Teledyne FLIR — karta produktu GF77 (dane techniczne, stan na 12.08.2026); Teledyne FLIR — seria G (dane techniczne, certyfikaty, stan na 12.08.2026); Konica Minolta — kamera QOGI (GMP03, GMP02); Konica Minolta — komunikat o kamerze GMP03 (2025); Opgal — rodziny produktów OGI (stan na 12.08.2026); Sensia — opis oferty na stronie firmy CORONA (strona producenta niedostępna automatycznie); Sierra-Olympic Technologies — Ventus OGI (rdzeń OEM); Workswell — GIS-320, ładunek OGI dla dronów

Discussed in the article: OGI solutions: handheld, fixed and drone cameras and QOGI — an overview

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