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Composting
Published in Sandy Cairncross, Richard Feachem, Environmental Health Engineering in the Tropics, 2018
Sandy Cairncross, Richard Feachem
Anaerobic composting or digestion, also known as fermentation or putrefaction, takes place in the absence of air or oxygen. It is the process by which organic muds are broken down by bacteria in marshes, producing marsh gas, consisting mainly of methane (CH4), but also of ammonia (NH3) and various sulfur-containing gases, which smell unpleasantly. A small amount of warmth is produced, but more of the energy is stored in the methane gas, which may be used for cooking or heating. Anaerobic composting is slow and unreliable as a method of pathogen destruction because it does not achieve sufficiently high temperatures. One method, the Bangalore method, requires alternate layers of refuse and nightsoil to be buried in trenches and left for at least six months.
The Evolution of Oil
Published in Michael Frank Hordeski, Alternative Fuels—The Future of Hydrogen, 2020
The methane, or paraffin, series starts as a simple, saturated, straight-chain, homologous series, advancing by a CH2 increment from its simplest member methane (CH2) to CH4 to complex molecules with more than 60 carbon atoms. A carbon atom has four arms (four valencies) which can retain four hydrogen atoms, since each hydrogen atom has only a single valency. The resulting hydrocarbon is methane, the chemical formula of which is expressed as CH4 or, alternatively, as CH3-H. This is the simplest of all the hydrocarbons and the most stable. It is the main component of natural gas and occurs in swamps as marsh gas from decaying vegetable matter.
Energy Resources
Published in Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough, Earth Materials, 2019
Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough
Anaerobic digestion can convert MSW into fuel just as pyrolysis does. However, anaerobic digestion takes place at low temperature and requires no heating. During this process, bacteria and other microorganisms break down organic material in the absence of oxygen. The products, generally termed biogas, comprise mostly methane and CO2 with a few other minor components including hydrogen sulfide. Sometimes, instead of using waste, crops are grown specifically for biogas production using anaerobic digestion. Anaerobic digestion is also the process responsible for creating marsh gas that causes some swamps to stink and is part of the standard process used to treat municipal sewage.
Mini review: Recent advances in long period fiber grating biological and chemical sensors
Published in Instrumentation Science & Technology, 2019
Methane is widely distributed in nature and is the main component of natural gas, oil field gas, and marsh gas. It is necessary to ensure the safety and reliability of the natural gas storage and transportation equipment for leak detection. Yang et al.[82] investigated a high-sensitivity LPFG methane sensor that contains a styrene-acrylonitrile/cryptophane nanofilm. The sensor was fabricated with an automatic dip-coater with a compact and uniform coating layer. The best results were obtained when the film thickness of the sensor was 484 nm. The best sensitivity and limits of detection of the sensor were 0.633 nm/% and 0.2%, respectively.