Faulgas

Faulgas is the term used in German-speaking contexts to describe gas produced by the anaerobic decomposition of organic matter under putrefying conditions. In common usage, it refers to methane-rich gases that originate from rotting vegetation, manure, sewage, landfills, and sediments. The principal components are methane (CH4) and carbon dioxide (CO2), typically with trace amounts of hydrogen sulfide (H2S), ammonia, and other volatile organic compounds.

Formation and composition: Faulgas forms when microorganisms decompose organic substrates without oxygen. Methanogenic archaea convert substrates to methane, while other microbes produce CO2 and small amounts of H2S and VOCs. The exact composition depends on the substrate, temperature, moisture, and microbial community. Biogenic faulgas is generated near the surface or within controlled environments; deeper geologic methane is sometimes distinguished as thermogenic and usually not called Faulgas in the same sense.

Occurrence and hazards: In landfills and wastewater facilities, Faulgas can accumulate in enclosed spaces, creating fire and explosion risks. H2S adds toxicity and odor concerns; methane is odorless but highly flammable and can form explosive mixtures with air. Monitoring and ventilation are required in mines, tunnels, and confined spaces.

Control and use: Gas collection systems capture faulgas for flaring or energy use in biogas plants. In mining practice, drainage and ventilation reduce accumulation. Environmentally, methane is a potent greenhouse gas, so capturing faulgas is valued for climate reasons.

Etymology and usage notes: The term derives from German faulen, to rot, and gas. In multilingual technical contexts, faulgas may be equated with sewer gas or biogas but is not exactly synonymous with all such gases.