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Anaerobic digestion

Anaerobic digestion is a sequence of processes by which microorganisms break down biodegradable material in the absence of oxygen. The process is used for industrial or domestic purposes to manage waste or to produce fuels. Much of the fermentation used industrially to produce food and drink products, as well as home fermentation, uses anaerobic digestion.

Anaerobic digestion occurs naturally in some soils and in lake and oceanic basin sediments, where it is usually referred to as "anaerobic activity". This is the source of marsh gas methane as discovered by Alessandro Volta in 1776.

The digestion process begins with bacterial hydrolysis of the input materials. Insoluble organic polymers, such as carbohydrates, are broken down to soluble derivatives that become available for other bacteria. Acidogenic bacteria then convert the sugars and amino acids into carbon dioxide, hydrogen, ammonia, and organic acids. In acetogenesis, bacteria convert these resulting organic acids into acetic acid, along with additional ammonia, hydrogen, and carbon dioxide amongst other compounds. Finally, methanogens convert these products to methane and carbon dioxide. The methanogenic archaea populations play an indispensable role in anaerobic wastewater treatments.

Anaerobic digestion is used as part of the process to treat biodegradable waste and sewage sludge. As part of an integrated waste management system, anaerobic digestion reduces the emission of landfill gas into the atmosphere. Anaerobic digesters can also be fed with purpose-grown energy crops, such as maize.

Anaerobic digestion is widely used as a source of renewable energy. The process produces a biogas, consisting of methane, carbon dioxide, and traces of other 'contaminant' gases. This biogas can be used directly as fuel, in combined heat and power gas engines or upgraded to natural gas-quality biomethane. The nutrient-rich digestate also produced can be used as fertilizer.

With the re-use of waste as a resource and new technological approaches that have lowered capital costs, anaerobic digestion has in recent years received increased attention among governments in a number of countries, among these the United Kingdom (2011), Germany, Denmark (2011), and the United States.

Process
Many microorganisms affect anaerobic digestion, including acetic acid-forming bacteria (acetogens) and methane-forming archaea (methanogens). These organisms promote a number of chemical processes in converting the biomass to biogas.

Gaseous oxygen is excluded from the reactions by physical containment. Anaerobes utilize electron acceptors from sources other than oxygen gas. These acceptors can be the organic material itself or may be supplied by inorganic oxides from within the input material. When the oxygen source in an anaerobic system is derived from the organic material itself, the 'intermediate' end products are primarily alcohols, aldehydes, and organic acids, plus carbon dioxide. In the presence of specialised methanogens, the intermediates are converted to the 'final' end products of methane, carbon dioxide, and trace levels of hydrogen sulfide. In an anaerobic system, the majority of the chemical energy contained within the starting material is released by methanogenic archaea as methane.

Populations of anaerobic microorganisms typically take a significant period of time to establish themselves to be fully effective. Therefore, common practice is to introduce anaerobic microorganisms from materials with existing populations, a process known as "seeding" the digesters, typically accomplished with the addition of sewage sludge or cattle slurry.

Process stages
The four key stages of anaerobic digestion involve hydrolysis, acidogenesis, acetogenesis and methanogenesis. The overall process can be described by the chemical reaction, where organic material such as glucose is biochemically digested into carbon dioxide (CO2) and methane (CH4) by the anaerobic microorganisms. C6H12O6 → 3CO2 + 3CH4 In most cases, biomass is made up of large organic polymers. For the bacteria in anaerobic digesters to access the energy potential of the material, these chains must first be broken down into their smaller constituent parts. These constituent parts, or monomers, such as sugars, are readily available to other bacteria. The process of breaking these chains and dissolving the smaller molecules into solution is called hydrolysis. Therefore, hydrolysis of these high-molecular-weight polymeric components is the necessary first step in anaerobic digestion. Through hydrolysis the complex organic molecules are broken down into simple sugars, amino acids, and fatty acids.
 * Hydrolysis

Acetate and hydrogen produced in the first stages can be used directly by methanogens. Other molecules, such as volatile fatty acids (VFAs) with a chain length greater than that of acetate must first be catabolised into compounds that can be directly used by methanogens.

The biological process of acidogenesis results in further breakdown of the remaining components by acidogenic (fermentative) bacteria. Here, VFAs are created, along with ammonia, carbon dioxide, and hydrogen sulfide, as well as other byproducts. The process of acidogenesis is similar to the way milk sours.
 * Acidogenesis

The third stage of anaerobic digestion is acetogenesis. Here, simple molecules created through the acidogenesis phase are further digested by acetogens to produce largely acetic acid, as well as carbon dioxide and hydrogen.
 * Acetogenesis

The terminal stage of anaerobic digestion is the biological process of methanogenesis. Here, methanogens use the intermediate products of the preceding stages and convert them into methane, carbon dioxide, and water. These components make up the majority of the biogas emitted from the system. Methanogenesis is sensitive to both high and low pHs and occurs between pH 6.5 and pH 8. The remaining, indigestible material the microbes cannot use and any dead bacterial remains constitute the digestate.
 * Methanogenesis

Configuration
Anaerobic digesters can be designed and engineered to operate using a number of different configurations and can be categorized into batch vs. continuous process mode, mesophilic vs. thermophilic temperature conditions, high vs. low portion of solids, and single stage vs. multistage processes. Continuous process requires more complex design, but still, it may be more economical than batch process, because batch process requires more initial building money and a larger volume of the digesters (spread across several batches) to handle the same amount of waste as a continuous process digester. Higher heat energy is required in a thermophilic system compared to a mesophilic system, but the thermophilic system requires much less time and has a larger gas output capacity and higher methane gas content, so one has to consider that trade-off carefully. For solids content, low will handle up to 15% solid content. Above this level is considered high solids content and can also be known as dry digestion. In a single stage process, one reactor houses the four anaerobic digestion steps. A multistage process utilizes two or more reactors for digestion to separate the methanogenesis and hydrolysis phases.

Batch or continuous
Anaerobic digestion can be performed as a batch process or a continuous process. In a batch system, biomass is added to the reactor at the start of the process. The reactor is then sealed for the duration of the process. In its simplest form batch processing needs inoculation with already processed material to start the anaerobic digestion. In a typical scenario, biogas production will be formed with a normal distribution pattern over time. Operators can use this fact to determine when they believe the process of digestion of the organic matter has completed. There can be severe odour issues if a batch reactor is opened and emptied before the process is well completed. A more advanced type of batch approach has limited the odour issues by integrating anaerobic digestion with in-vessel composting. In this approach inoculation takes place through the use of recirculated degasified percolate. After anaerobic digestion has completed, the biomass is kept in the reactor which is then used for in-vessel composting before it is opened As the batch digestion is simple and requires less equipment and lower levels of design work, it is typically a cheaper form of digestion. Using more than one batch reactor at a plant can ensure constant production of biogas.

In continuous digestion processes, organic matter is constantly added (continuous complete mixed) or added in stages to the reactor (continuous plug flow; first in – first out). Here, the end products are constantly or periodically removed, resulting in constant production of biogas. A single or multiple digesters in sequence may be used. Examples of this form of anaerobic digestion include continuous stirred-tank reactors, upflow anaerobic sludge blankets, expanded granular sludge beds, and internal circulation reactors.

Temperature
The two conventional operational temperature levels for anaerobic digesters determine the species of methanogens in the digesters:
 * Mesophilic digestion takes place optimally around 30 to 38 °C, or at ambient temperatures between 20 and 45 °C, where mesophiles are the primary microorganisms present.
 * Thermophilic digestion takes place optimally around 49 to 57 °C, or at elevated temperatures up to 70 °C, where thermophiles are the primary microorganisms present.

A limit case has been reached in Bolivia, with anaerobic digestion in temperature working conditions of less than 10 °C. The anaerobic process is very slow, taking more than three times the normal mesophilic time process. In experimental work at University of Alaska Fairbanks, a 1,000-litre digester using psychrophiles harvested from "mud from a frozen lake in Alaska" has produced 200–300 litres of methane per day, about 20 to 30% of the output from digesters in warmer climates. Mesophilic species outnumber thermophiles, and they are also more tolerant to changes in environmental conditions than thermophiles. Mesophilic systems are, therefore, considered to be more stable than thermophilic digestion systems. In contrast, while thermophilic digestion systems are considered less stable, their energy input is higher, with more biogas being removed from the organic matter in an equal amount of time. The increased temperatures facilitate faster reaction rates, and thus faster gas yields. Operation at higher temperatures facilitates greater pathogen reduction of the digestate. In countries where legislation, such as the Animal By-Products Regulations in the European Union, requires digestate to meet certain levels of pathogen reduction there may be a benefit to using thermophilic temperatures instead of mesophilic.

Additional pre-treatment can be used to reduce the necessary retention time to produce biogas. For example, certain processes shred the substrates to increase the surface area or use a thermal pretreatment stage (such as pasteurisation) to significantly enhance the biogas output. The pasteurisation process can also be used to reduce the pathogenic concentration in the digestate, leaving the anaerobic digester. Pasteurisation may be achieved by heat treatment combined with maceration of the solids.

Solids content
In a typical scenario, three different operational parameters are associated with the solids content of the feedstock to the digesters:
 * High solids (dry—stackable substrate)
 * High solids (wet—pumpable substrate)
 * Low solids (wet—pumpable substrate)

High solids (dry) digesters are designed to process materials with a solids content between 25 and 40%. Unlike wet digesters that process pumpable slurries, high solids (dry – stackable substrate) digesters are designed to process solid substrates without the addition of water. The primary styles of dry digesters are continuous vertical plug flow and batch tunnel horizontal digesters. Continuous vertical plug flow digesters are upright, cylindrical tanks where feedstock is continuously fed into the top of the digester, and flows downward by gravity during digestion. In batch tunnel digesters, the feedstock is deposited in tunnel-like chambers with a gas-tight door. Neither approach has mixing inside the digester. The amount of pretreatment, such as contaminant removal, depends both upon the nature of the waste streams being processed and the desired quality of the digestate. Size reduction (grinding) is beneficial in continuous vertical systems, as it accelerates digestion, while batch systems avoid grinding and instead require structure (e.g. yard waste) to reduce compaction of the stacked pile. Continuous vertical dry digesters have a smaller footprint due to the shorter effective retention time and vertical design. Wet digesters can be designed to operate in either a high-solids content, with a total suspended solids (TSS) concentration greater than ~20%, or a low-solids concentration less than ~15%.

High solids (wet) digesters process a thick slurry that requires more energy input to move and process the feedstock. The thickness of the material may also lead to associated problems with abrasion. High solids digesters will typically have a lower land requirement due to the lower volumes associated with the moisture. High solids digesters also require correction of conventional performance calculations (e.g. gas production, retention time, kinetics, etc.) originally based on very dilute sewage digestion concepts, since larger fractions of the feedstock mass are potentially convertible to biogas.

Low solids (wet) digesters can transport material through the system using standard pumps that require significantly lower energy input. Low solids digesters require a larger amount of land than high solids due to the increased volumes associated with the increased liquid-to-feedstock ratio of the digesters. There are benefits associated with operation in a liquid environment, as it enables more thorough circulation of materials and contact between the bacteria and their food. This enables the bacteria to more readily access the substances on which they are feeding, and increases the rate of gas production.

Complexity
Digestion systems can be configured with different levels of complexity. In a single-stage digestion system (one-stage), all of the biological reactions occur within a single, sealed reactor or holding tank. Using a single stage reduces construction costs, but results in less control of the reactions occurring within the system. Acidogenic bacteria, through the production of acids, reduce the pH of the tank. Methanogenic archaea, as outlined earlier, operate in a strictly defined pH range. Therefore, the biological reactions of the different species in a single-stage reactor can be in direct competition with each other. Another one-stage reaction system is an anaerobic lagoon. These lagoons are pond-like, earthen basins used for the treatment and long-term storage of manures. Here the anaerobic reactions are contained within the natural anaerobic sludge contained in the pool.

In a two-stage digestion system (multistage), different digestion vessels are optimised to bring maximum control over the bacterial communities living within the digesters. Acidogenic bacteria produce organic acids and more quickly grow and reproduce than methanogenic archaea. Methanogenic archaea require stable pH and temperature to optimise their performance.

Under typical circumstances, hydrolysis, acetogenesis, and acidogenesis occur within the first reaction vessel. The organic material is then heated to the required operational temperature (either mesophilic or thermophilic) prior to being pumped into a methanogenic reactor. The initial hydrolysis or acidogenesis tanks prior to the methanogenic reactor can provide a buffer to the rate at which feedstock is added. Some European countries require a degree of elevated heat treatment to kill harmful bacteria in the input waste. In this instance, there may be a pasteurisation or sterilisation stage prior to digestion or between the two digestion tanks. Notably, it is not possible to completely isolate the different reaction phases, and often some biogas is produced in the hydrolysis or acidogenesis tanks.

Residence time
The residence time in a digester varies with the amount and type of feed material, and with the configuration of the digestion system. In a typical two-stage mesophilic digestion, residence time varies between 15 and 40 days, while for a single-stage thermophilic digestion, residence times is normally faster and takes around 14 days. The plug-flow nature of some of these systems will mean the full degradation of the material may not have been realised in this timescale. In this event, digestate exiting the system will be darker in colour and will typically have more odour.

In the case of an upflow anaerobic sludge blanket digestion (UASB), hydraulic residence times can be as short as 1 hour to 1 day, and solid retention times can be up to 90 days. In this manner, a UASB system is able to separate solids and hydraulic retention times with the use of a sludge blanket. Continuous digesters have mechanical or hydraulic devices, depending on the level of solids in the material, to mix the contents, enabling the bacteria and the food to be in contact. They also allow excess material to be continuously extracted to maintain a reasonably constant volume within the digestion tanks.

Pressure
A recent development in anaerobic reactor design is High-pressure anaerobic digestion (HPAD) also referred to a Autogenerative High Pressure Digestion (AHPD). This technique produces a biogas with a elevated methane content. The produced carbon dioxide in biogas dissolves more into the water phase under pressure then methane does. Hence the produced biogas is richer in methane. Research at the University of Groningen demonstrated that the bacterial community changes in composition under the influence of pressure. Individual bacteria species have their optimum circumstances in which they grow and replicate the fastest. Commonly known are pH, temperature, salinity etc. but pressure is also one of them. Some species have adapted to life in the deep oceans where pressure is much higher than at sea level. This makes it possible in similar vein as other process parameters such as Temperature, Retention Time, pH to influence the anaerobic digestion process.

Inhibition
The anaerobic digestion process can be inhibited by several compounds, affecting one or more of the bacterial groups responsible for the different organic matter degradation steps. The degree of the inhibition depends, among other factors, on the concentration of the inhibitor in the digester. Potential inhibitors are ammonia, sulfide, light metal ions (Na, K, Mg, Ca, Al), heavy metals, some organics (chlorophenols, halogenated aliphatics, N-substituted aromatics, long chain fatty acids), etc.

Total ammonia nitrogen (TAN) has been shown to inhibit production of methane. Furthermore, it destabilises the microbial community, impacting the synthesis of acetic acid. Acetic acid is one of the driving forces in methane production. At an excess of 5000 mg/L TAN, pH adjustment is needed to keep the reaction stable. A TAN concentration above 1700– 1800 mg/L inhibits methane production and yield decreases at greater TAN concentrations. High TAN concentrations cause the reaction to turn acidic and lead to a domino effect of inhibition. Total ammonia nitrogen is the combination of free ammonia and ionized ammonia. TAN is produced through degrading material high in nitrogen, typically proteins and will naturally build in anaerobic digestion. This is depending on the organic feed stock fed to the system. In typical wastewater treatment practices, TAN reduction is done with via nitrification. Nitrification is an aerobic process where TAN is consumed by aerobic heterotrophic bacteria. These bacteria release nitrate and nitrite which are later converted to nitrogen gas through the denitrification process. Hydrolysis and acidogenesis can also be impacted by TAN concentration. In mesophilic conditions, inhibition for hydrolysis was found to occur at 5500 mg/L TAN, while acidogenesis inhibition occurs at 6500 mg/L TAN.

Feedstocks

The most important initial issue when considering the application of anaerobic digestion systems is the feedstock to the process. Almost any organic material can be processed with anaerobic digestion; however, if biogas production is the aim, the level of putrescibility is the key factor in its successful application. The more putrescible (digestible) the material, the higher the gas yields possible from the system.

Feedstocks can include biodegradable waste materials, such as waste paper, grass clippings, leftover food, sewage, and animal waste. Woody wastes are the exception, because they are largely unaffected by digestion, as most anaerobes are unable to degrade lignin. Xylophagous anaerobes (lignin consumers) or high temperature pretreatment, such as pyrolysis, can be used to break lignin down. Anaerobic digesters can also be fed with specially grown energy crops, such as silage, for dedicated biogas production. In Germany and continental Europe, these facilities are referred to as "biogas" plants. A codigestion or cofermentation plant is typically an agricultural anaerobic digester that accepts two or more input materials for simultaneous digestion.

The length of time required for anaerobic digestion depends on the chemical complexity of the material. Material rich in easily digestible sugars breaks down quickly, whereas intact lignocellulosic material rich in cellulose and hemicellulose polymers can take much longer to break down. Anaerobic microorganisms are generally unable to break down lignin, the recalcitrant aromatic component of biomass.

Anaerobic digesters were originally designed for operation using sewage sludge and manures. Sewage and manure are not, however, the material with the most potential for anaerobic digestion, as the biodegradable material has already had much of the energy content taken out by the animals that produced it. Therefore, many digesters operate with codigestion of two or more types of feedstock. For example, in a farm-based digester that uses dairy manure as the primary feedstock, the gas production may be significantly increased by adding a second feedstock, e.g., grass and corn (typical on-farm feedstock), or various organic byproducts, such as slaughterhouse waste, fats, oils and grease from restaurants, organic household waste, etc. (typical off-site feedstock).

Digesters processing dedicated energy crops can achieve high levels of degradation and biogas production. Slurry-only systems are generally cheaper, but generate far less energy than those using crops, such as maize and grass silage; by using a modest amount of crop material (30%), an anaerobic digestion plant can increase energy output tenfold for only three times the capital cost, relative to a slurry-only system.

Moisture content
A second consideration related to the feedstock is moisture content. Drier, stackable substrates, such as food and yard waste, are suitable for digestion in tunnel-like chambers. Tunnel-style systems typically have near-zero wastewater discharge, as well, so this style of system has advantages where the discharge of digester liquids are a liability. The wetter the material, the more suitable it will be to handling with standard pumps instead of energy-intensive concrete pumps and physical means of movement. Also, the wetter the material, the more volume and area it takes up relative to the levels of gas produced. The moisture content of the target feedstock will also affect what type of system is applied to its treatment. To use a high-solids anaerobic digester for dilute feedstocks, bulking agents, such as compost, should be applied to increase the solids content of the input material. Another key consideration is the carbon:nitrogen ratio of the input material. This ratio is the balance of food a microbe requires to grow; the optimal C:N ratio is 20–30:1. Excess N can lead to ammonia inhibition of digestion.

Contamination
The level of contamination of the feedstock material is a key consideration when using wet digestion or plug-flow digestion.

If the feedstock to the digesters has significant levels of physical contaminants, such as plastic, glass, or metals, then processing to remove the contaminants will be required for the material to be used. If it is not removed, then the digesters can be blocked and will not function efficiently. This contamination issue does not occur with dry digestion or solid-state anaerobic digestion (SSAD) plants, since SSAD handles dry, stackable biomass with a high percentage of solids (40-60%) in gas-tight chambers called fermenter boxes. It is with this understanding that mechanical biological treatment plants are designed. The higher the level of pretreatment a feedstock requires, the more processing machinery will be required, and, hence, the project will have higher capital costs. National Non-Food Crops Centre.

After sorting or screening to remove any physical contaminants from the feedstock, the material is often shredded, minced, and mechanically or hydraulically pulped to increase the surface area available to microbes in the digesters and, hence, increase the speed of digestion. The maceration of solids can be achieved by using a chopper pump to transfer the feedstock material into the airtight digester, where anaerobic treatment takes place.

Substrate composition
Substrate composition is a major factor in determining the methane yield and methane production rates from the digestion of biomass. Techniques to determine the compositional characteristics of the feedstock are available, while parameters such as solids, elemental, and organic analyses are important for digester design and operation. Methane yield can be estimated from the elemental composition of substrate along with an estimate of its degradability (the fraction of the substrate that is converted to biogas in a reactor). In order to predict biogas composition (the relative fractions of methane and carbon dioxide) it is necessary to estimate carbon dioxide partitioning between the aqueous and gas phases, which requires additional information (reactor temperature, pH, and substrate composition) and a chemical speciation model. Direct measurements of biomethanation potential are also made using gas evolution or more recent gravimetric assays.

Applications

Using anaerobic digestion technologies can help to reduce the emission of greenhouse gases in a number of key ways:
 * Replacement of fossil fuels
 * Reducing or eliminating the energy footprint of waste treatment plants
 * Reducing methane emission from landfills
 * Displacing industrially produced chemical fertilizers
 * Reducing vehicle movements
 * Reducing electrical grid transportation losses
 * Reducing usage of LP Gas for cooking
 * An important component of the Zero Waste initiatives.

Waste and wastewater treatment
Anaerobic digestion is particularly suited to organic material, and is commonly used for industrial effluent, wastewater and sewage sludge treatment. Anaerobic digestion, a simple process, can greatly reduce the amount of organic matter which might otherwise be destined to be dumped at sea, dumped in landfills, or burnt in incinerators.

Pressure from environmentally related legislation on solid waste disposal methods in developed countries has increased the application of anaerobic digestion as a process for reducing waste volumes and generating useful byproducts. It may either be used to process the source-separated fraction of municipal waste or alternatively combined with mechanical sorting systems, to process residual mixed municipal waste. These facilities are called mechanical biological treatment plants.

If the putrescible waste processed in anaerobic digesters were disposed of in a landfill, it would break down naturally and often anaerobically. In this case, the gas will eventually escape into the atmosphere. As methane is about 20 times more potent as a greenhouse gas than carbon dioxide, this has significant negative environmental effects.

In countries that collect household waste, the use of local anaerobic digestion facilities can help to reduce the amount of waste that requires transportation to centralized landfill sites or incineration facilities. This reduced burden on transportation reduces carbon emissions from the collection vehicles. If localized anaerobic digestion facilities are embedded within an electrical distribution network, they can help reduce the electrical losses associated with transporting electricity over a national grid.

Anaerobic digestion can be used for the remediation sludge polluted with PFAS. A 2024 study has shown that anaerobic digestion, combined with adsorption in activated carbon and voltage application can remove up to 61% of PFAS from sewage sludge.

Power generation
In developing countries, simple home and farm-based anaerobic digestion systems offer the potential for low-cost energy for cooking and lighting. From 1975, China and India have both had large, government-backed schemes for adaptation of small biogas plants for use in the household for cooking and lighting. At present, projects for anaerobic digestion in the developing world can gain financial support through the United Nations Clean Development Mechanism if they are able to show they provide reduced carbon emissions.

Methane and power produced in anaerobic digestion facilities can be used to replace energy derived from fossil fuels, and hence reduce emissions of greenhouse gases, because the carbon in biodegradable material is part of a carbon cycle. The carbon released into the atmosphere from the combustion of biogas has been removed by plants for them to grow in the recent past, usually within the last decade, but more typically within the last growing season. If the plants are regrown, taking the carbon out of the atmosphere once more, the system will be carbon neutral. In contrast, carbon in fossil fuels has been sequestered in the earth for many millions of years, the combustion of which increases the overall levels of carbon dioxide in the atmosphere. Power generation through anaerobic digestors is best suited to large-scale operations, rather than small farms, as large operations have the volume of manure that is able to make the systems financially viable.

Biogas from sewage sludge treatment is sometimes used to run a gas engine to produce electrical power, some or all of which can be used to run the sewage works. Some waste heat from the engine is then used to heat the digester. The waste heat is, in general, enough to heat the digester to the required temperatures. The power potential from sewage works is limited – in the UK, there are about 80 MW total of such generation, with the potential to increase to 150 MW, which is insignificant compared to the average power demand in the UK of about 35,000 MW. The scope for biogas generation from nonsewage waste biological matter – energy crops, food waste, abattoir waste, etc. - is much higher, estimated to be capable of about 3,000 MW. Farm biogas plants using animal waste and energy crops are expected to contribute to reducing CO2 emissions and strengthen the grid, while providing UK farmers with additional revenues.

Some countries offer incentives in the form of, for example, feed-in tariffs for feeding electricity onto the power grid to subsidize green energy production.

In Oakland, California at the East Bay Municipal Utility District's main wastewater treatment plant (EBMUD), food waste is currently codigested with primary and secondary municipal wastewater solids and other high-strength wastes. Compared to municipal wastewater solids digestion alone, food waste codigestion has many benefits. Anaerobic digestion of food waste pulp from the EBMUD food waste process provides a higher normalized energy benefit, compared to municipal wastewater solids: 730 to 1,300 kWh per dry ton of food waste applied compared to 560 to 940 kWh per dry ton of municipal wastewater solids applied.

Grid injection
Biogas grid-injection is the injection of biogas into the natural gas grid. The raw biogas has to be previously upgraded to biomethane. This upgrading implies the removal of contaminants such as hydrogen sulphide or siloxanes, as well as the carbon dioxide. Several technologies are available for this purpose, the most widely implemented being pressure swing adsorption (PSA), water or amine scrubbing (absorption processes) and, in recent years, membrane separation. As an alternative, the electricity and the heat can be used for on-site generation, resulting in a reduction of losses in the transportation of energy. Typical energy losses in natural gas transmission systems range from 1–2%, whereas the current energy losses on a large electrical system range from 5–8%.

In October 2010, Didcot Sewage Works became the first in the UK to produce biomethane gas supplied to the national grid, for use in up to 200 homes in Oxfordshire. By 2017, UK electricity firm Ecotricity plan to have digester fed by locally sourced grass fueling 6000 homes

Vehicle fuel
After upgrading with the above-mentioned technologies, the biogas (transformed into biomethane) can be used as vehicle fuel in adapted vehicles. This use is very extensive in Sweden, where over 38,600 gas vehicles exist, and 60% of the vehicle gas is biomethane generated in anaerobic digestion plants.

Fertiliser and soil conditioner
The solid, fibrous component of the digested material can be used as a soil conditioner to increase the organic content of soils. Digester liquor can be used as a fertiliser to supply vital nutrients to soils instead of chemical fertilisers that require large amounts of energy to produce and transport. The use of manufactured fertilisers is, therefore, more carbon-intensive than the use of anaerobic digester liquor fertiliser. In countries such as Spain, where many soils are organically depleted, the markets for the digested solids can be equally as important as the biogas.

Cooking gas
By using a bio-digester, which produces the bacteria required for decomposing, cooking gas is generated. The organic waste like fallen leaves, kitchen waste, food waste etc. are fed into a crusher unit, where it is mixed with a small amount of water. The mixture is then fed into the bio-digester, where the archaea decomposes it to produce cooking gas. This gas is piped to kitchen stove. A 2 cubic meter bio-digester can produce 2 cubic meters of cooking gas. This is equivalent to 1 kg of LPG. The notable advantage of using a bio-digester is the sludge which is a rich organic manure.

Products
The three principal products of anaerobic digestion are biogas, digestate, and water.

Biogas

Biogas is the ultimate waste product of the bacteria feeding off the input biodegradable feedstock (the methanogenesis stage of anaerobic digestion is performed by archaea, a micro-organism on a distinctly different branch of the phylogenetic tree of life to bacteria), and is mostly methane and carbon dioxide, with a small amount hydrogen and trace hydrogen sulfide. (As-produced, biogas also contains water vapor, with the fractional water vapor volume a function of biogas temperature). Most of the biogas is produced during the middle of the digestion, after the bacterial population has grown, and tapers off as the putrescible material is exhausted. The gas is normally stored on top of the digester in an inflatable gas bubble or extracted and stored next to the facility in a gas holder.

The methane in biogas can be burned to produce both heat and electricity, usually with a reciprocating engine or microturbine often in a cogeneration arrangement where the electricity and waste heat generated are used to warm the digesters or to heat buildings. Excess electricity can be sold to suppliers or put into the local grid. Electricity produced by anaerobic digesters is considered to be renewable energy and may attract subsidies. Biogas does not contribute to increasing atmospheric carbon dioxide concentrations because the gas is not released directly into the atmosphere and the carbon dioxide comes from an organic source with a short carbon cycle.

Biogas may require treatment or 'scrubbing' to refine it for use as a fuel. Hydrogen sulfide, a toxic product formed from sulfates in the feedstock, is released as a trace component of the biogas. National environmental enforcement agencies, such as the U.S. Environmental Protection Agency or the English and Welsh Environment Agency, put strict limits on the levels of gases containing hydrogen sulfide, and, if the levels of hydrogen sulfide in the gas are high, gas scrubbing and cleaning equipment (such as amine gas treating) will be needed to process the biogas to within regionally accepted levels. Alternatively, the addition of ferrous chloride FeCl2 to the digestion tanks inhibits hydrogen sulfide production.

Volatile siloxanes can also contaminate the biogas; such compounds are frequently found in household waste and wastewater. In digestion facilities accepting these materials as a component of the feedstock, low-molecular-weight siloxanes volatilise into biogas. When this gas is combusted in a gas engine, turbine, or boiler, siloxanes are converted into silicon dioxide (SiO2), which deposits internally in the machine, increasing wear and tear. Practical and cost-effective technologies to remove siloxanes and other biogas contaminants are available at the present time. In certain applications, in situ treatment can be used to increase the methane purity by reducing the offgas carbon dioxide content, purging the majority of it in a secondary reactor.

In countries such as Switzerland, Germany, and Sweden, the methane in the biogas may be compressed for it to be used as a vehicle transportation fuel or input directly into the gas mains. In countries where the driver for the use of anaerobic digestion are renewable electricity subsidies, this route of treatment is less likely, as energy is required in this processing stage and reduces the overall levels available to sell.

Digestate
Digestate is the solid remnants of the original input material to the digesters that the microbes cannot use. It also consists of the mineralised remains of the dead bacteria from within the digesters. Digestate can come in three forms: fibrous, liquor, or a sludge-based combination of the two fractions. In two-stage systems, different forms of digestate come from different digestion tanks. In single-stage digestion systems, the two fractions will be combined and, if desired, separated by further processing.

The second byproduct (acidogenic digestate) is a stable, organic material consisting largely of lignin and cellulose, but also of a variety of mineral components in a matrix of dead bacterial cells; some plastic may be present. The material resembles domestic compost and can be used as such or to make low-grade building products, such as fibreboard. The solid digestate can also be used as feedstock for ethanol production.

The third byproduct is a liquid (methanogenic digestate) rich in nutrients, which can be used as a fertiliser, depending on the quality of the material being digested. Levels of potentially toxic elements (PTEs) should be chemically assessed. This will depend upon the quality of the original feedstock. In the case of most clean and source-separated biodegradable waste streams, the levels of PTEs will be low. In the case of wastes originating from industry, the levels of PTEs may be higher and will need to be taken into consideration when determining a suitable end use for the material.

Digestate typically contains elements, such as lignin, that cannot be broken down by the anaerobic microorganisms. Also, the digestate may contain ammonia that is phytotoxic, and may hamper the growth of plants if it is used as a soil-improving material. For these two reasons, a maturation or composting stage may be employed after digestion. Lignin and other materials are available for degradation by aerobic microorganisms, such as fungi, helping reduce the overall volume of the material for transport. During this maturation, the ammonia will be oxidized into nitrates, improving the fertility of the material and making it more suitable as a soil improver. Large composting stages are typically used by dry anaerobic digestion technologies.

Wastewater
The final output from anaerobic digestion systems is water, which originates both from the moisture content of the original waste that was treated and water produced during the microbial reactions in the digestion systems. This water may be released from the dewatering of the digestate or may be implicitly separate from the digestate.

The wastewater exiting the anaerobic digestion facility will typically have elevated levels of biochemical oxygen demand (BOD) and chemical oxygen demand (COD). These measures of the reactivity of the effluent indicate an ability to pollute. Some of this material is termed 'hard COD', meaning it cannot be accessed by the anaerobic bacteria for conversion into biogas. If this effluent were put directly into watercourses, it would negatively affect them by causing eutrophication. As such, further treatment of the wastewater is often required. This treatment will typically be an oxidation stage wherein air is passed through the water in a sequencing batch reactors or reverse osmosis unit.

History

Reported scientific interest in the manufacturing of gas produced by the natural decomposition of organic matter dates from the 17th century, when Robert Boyle (1627-1691) and Stephen Hales (1677-1761) noted that disturbing the sediment of streams and lakes released flammable gas. In 1778, the Italian physicist Alessandro Volta (1745-1827), the father of electrochemistry, scientifically identified that gas as methane.

In 1808 Sir Humphry Davy proved the presence of methane in the gases produced by cattle manure. The first known anaerobic digester was built in 1859 at a leper colony in Bombay in India. In 1895, the technology was developed in Exeter, England, where a septic tank was used to generate gas for the sewer gas destructor lamp, a type of gas lighting. Also in England, in 1904, the first dual-purpose tank for both sedimentation and sludge treatment was installed in Hampton, London. By the early 20th century, anaerobic digestion systems began to resemble the technology as it appears today. In 1906, Karl Imhoff created the Imhoff tank; an early form of anaerobic digester and model wastewater treatment system throughout the early 20th century. After 1920, closed tank systems began to replace the previously common use of anaerobic lagoons – covered earthen basins used to treat volatile solids. Research on anaerobic digestion began in earnest in the 1930s.

Around the time of World War I, production from biofuels slowed as petroleum production increased and its uses were identified. While fuel shortages during World War II re-popularized anaerobic digestion, interest in the technology decreased again after the war ended. Similarly, the 1970s energy crisis sparked interest in anaerobic digestion. In addition to high energy prices, factors affecting the adoption of anaerobic digestion systems include receptivity to innovation, pollution penalties, policy incentives, and the availability of subsidies and funding opportunities.

Modern geographical distribution
Today, anaerobic digesters are commonly found alongside farms to reduce nitrogen run-off from manure, or wastewater treatment facilities to reduce the costs of sludge disposal. Agricultural anaerobic digestion for energy production has become most popular in Germany, where there were 8,625 digesters in 2014. In the United Kingdom, there were 259 facilities by 2014, and 500 projects planned to become operational by 2019. In the United States, there were 191 operational plants across 34 states in 2012. Policy may explain why adoption rates are so different across these countries.

Feed-in tariffs in Germany were enacted in 1991, also known as FIT, providing long-term contracts compensating investments in renewable energy generation. Consequently, between 1991 and 1998 the number of anaerobic digester plants in Germany grew from 20 to 517. In the late 1990s, energy prices in Germany varied and investors became unsure of the market's potential. The German government responded by amending FIT four times between 2000 and 2011, increasing tariffs and improving the profitability of anaerobic digestion, and resulting in reliable returns for biogas production and continued high adoption rates across the country.

Incidents involving digesters
Anaerobic digesters have caused Fish kills (e.g. River Mole, Devon, River Teifi, Afon Llynfi, and loss of human life (e.g. Avonmouth explosion)

There have been explosions of Anaerobic Digesters in the US (Jay, Maine Pixelle Specialty Solutions' Androscoggin Mill; Pensacola (Cantonment) 22 January 2017 (Kamyr digester explosion); EPDM failure March 2013 Aumsville, Oregon; February 6, 1987, Pennsylvania two workers at a wastewater treatment plant were re-draining a sewage digester when an explosion lifted the 30-ton floating cover, killing both workers instantly; Southwest Wastewater Treatment Plant in Springfield, Missouri), in the UK (for example at Avonmouth and at Harper Adams College, Newport, Shropshire ), plus In Europe, there were about 800 accidents on biogas plants between 2005 and 2015, e.g. in France (Saint-Fargeau) (though few of them were 'serious' with direct consequences for the human population). Fortunately, according to one source, 'less than a dozen of them had consequences on humans'- for example, the incident at Rhadereistedt, Germany (4 dead).

Safety analyses have included  a 2016 study compiled a database of 169 accidents involving ADs.

title: Anaerobic digestion


text:
Culture of fear

Culture of fear (or climate of fear) is the concept that people may incite fear in the general public to achieve political or workplace goals through emotional bias. It was developed as a sociological framework by Frank Furedi and has been more recently popularized by the American sociologist Barry Glassner.

In politics
Nazi German politician Hermann Göring explained how people can be made fearful and to support a war they would otherwise oppose:

"The people don't want war, but they can always be brought to the bidding of the leaders. This is easy. All you have to do is tell them they are being attacked, and denounce the pacifists for lack of patriotism and for exposing the country to danger.  It works the same in every country."

In her book State and Opposition in Military Brazil, Maria Helena Moreira Alves found a "culture of fear" was implemented as part of political repression since 1964. She used the term to describe methods implemented by the national security apparatus of Brazil in its effort to equate political participation with risk of arrest and torture. Cassação (English: cassation) is one such mechanism used to punish members of the military by legally declaring them dead. This enhanced the potential for political control through intensifying the culture of fear as a deterrent to opposition.

Alves found the changes of the National Security Law of 1969, as beginning the use of "economic exploitation, physical repression, political control, and strict censorship" to establish a "culture of fear" in Brazil. The three psychological components of the culture of fear included silence through censorship, sense of isolation, and a "generalized belief that all channels of opposition were closed." A "feeling of complete hopelessness" prevailed, in addition to "withdrawal from opposition activity."

Former U.S. National Security Advisor Zbigniew Brzezinski argues that the U.S. government's use of the term "war on terror" was deliberately intended to generate a culture of fear because it "obscures reason, intensifies emotions and makes it easier for demagogic politicians to mobilize the public on behalf of the policies they want to pursue".

Frank Furedi, a former professor of Sociology and writer for Spiked magazine, says that the present-day culture of fear did not begin with the September 11 attacks. Before, he argues, public panics were widespread on everything from genetically modified food and mobile phones, to global warming and foot-and-mouth disease. Like Durodié, Furedi argues that perceptions of risk, ideas about safety and controversies over health, the environment and technology have little to do with science or empirical evidence. Rather, they are shaped by cultural assumptions about human vulnerability. Furedi says that "we need a grown-up discussion about our post-September 11 world, based on a reasoned evaluation of all the available evidence rather than on irrational fears for the future."

British academics Gabe Mythen and Sandra Walklate argue that following the September 11 attacks, 2004 Madrid train bombings, and 2005 London bombings, government agencies developed a discourse of "new terrorism" in a cultural climate of fear and uncertainty. British researchers argued that these processes reduced notions of public safety and created the simplistic image of a non-white "terroristic other" that has negative consequences for ethnic minority groups in the UK.

In his 2004 BBC documentary film series The Power of Nightmares, subtitled The Rise of the Politics of Fear, the journalist Adam Curtis argues that politicians use fears to increase their power and control over society. Though he does not use the term "culture of fear," what Curtis describes in his film is a reflection of this concept. He looks at the American neo-conservative movement and its depiction of the threat first from the Soviet Union and then from radical Islamists. Curtis insists there has been a largely illusory fear of terrorism in the West since the September 11 attacks and that politicians such as George W. Bush and Tony Blair had stumbled on a new force to restore their power and authority; using the fear of an organised "web of evil" from which they could protect their people. Curtis's film castigated the media, security forces, and the Bush administration for expanding their power in this way. The film features Bill Durodié, then Director of the International Centre for Security Analysis, and Senior Research Fellow in the International Policy Institute, King's College London, saying that to call this network an "invention" would be too strong a term, instead asserting that it probably does not exist and is largely a "(projection) of our own worst fears, and that what we see is a fantasy that's been created."

In the workplace
Ashforth discussed potentially destructive sides of leadership and identified what he referred to as petty tyrants: leaders who exercise a tyrannical style of management, resulting in a climate of fear in the workplace. Partial or intermittent negative reinforcement can create an effective climate of fear and doubt. When employees get the sense that bullies are tolerated, a climate of fear may be the result. Several studies have confirmed a relationship between bullying, on one hand, and an autocratic leadership and an authoritarian way of settling conflicts or dealing with disagreements, on the other. An authoritarian style of leadership may create a climate of fear, with little or no room for dialogue and with complaining being considered futile.

In a study of public-sector union members, approximately one in five workers reported having considered leaving the workplace as a result of witnessing bullying taking place. Rayner explained the figures by pointing to the presence of a climate of fear in which employees considered reporting to be unsafe, where bullies had been tolerated previously despite management knowing of the presence of bullying. Individual differences in sensitivity to reward, punishment and motivation have been studied under the premises of reinforcement sensitivity theory and have also been applied to workplace performance. A culture of fear at the workplace runs contrary to the "key principles" established by W. Edwards Deming for managers to transform business effectiveness. One of his fourteen principles is to drive out fear in order to allow everyone to work effectively for the company.

Impact of the media
The consumption of mass media has had a profound effect on instilling the fear of terrorism in the United States, though acts of terror are a rare phenomenon. Beginning in the 1960s, George Gerbner and his colleagues have accelerated the study of the relationship that exists between media consumption and the fear of crime. According to Gerbner, television and other forms of mass media create a worldview that is reflective of "recurrent media messages", rather than one that is based on reality. Many Americans are exposed to some form of media on a daily basis, with television and social media platforms being the most used methods to receive both local and international news, and as such this is how most receive news and details that center around violent crime and acts of terror. With the rise in use of smartphones and social media, people are bombarded with constant news updates, and able to read stories related to terrorism, stories that come from all corners of the globe. Media fuels fear of terrorism and other threats to national security, all of which have negative psychological effects on the population, such as depression, anxiety, and insomnia. Politicians conduct interviews, televised or otherwise, and utilize their social media platforms immediately after violent crimes and terrorist acts, to further cement the fear of terrorism into the minds of their constituents.

Publications
Sorted upwards by date, most recent last.

 * The Formation of the National Security State: the State and the Opposition in Military Brazil, Volume 2 (1982) by Maria Helena Moreira Alves
 * Risk Society, Towards a New Modernity (1989), by Ulrich Beck, ISBN 978-0-8039-8346-5 [the term was coined in German by the same author in Risikogesellschaft. Die organisierte Unverantwortlichkeit (this subtitle means in English: "Organized irresponsibility"), a speech given at St. Gallen College, Switzerland, 16pp., in 1989, then published as full-length book with the title: Risikogesellschaft, Suhrkamp, 1989, 391pp., ISBN 3-518-11365-8]
 * The Culture of Fear (2000), by Barry Glassner ISBN 0-465-01490-9
 * Creating Fear: News and the Construction of a Crisis (2002), by David L. Altheide, Aldine de Gruyter, 223pp., ISBN 978-0-202-30660-5
 * Kingdom of Fear: Loathsome Secrets of a Star-Crossed Child in the Final Days of the American Century (2003), by Hunter S. Thompson, Simon & Schuster, ISBN 0-684-87324-9
 * The Climate of Fear (2004), by Wole Soyinka, BBC Reith Lectures 2004, London, Profile Books, 155pp., ISBN 1-86197-783-2
 * State of Fear (2004), Michael Crichton, ISBN 0-06-621413-0
 * Culture of Fear: Risk taking and the morality of low expectation (1997), by Frank Furedi, ISBN 0-8264-7616-3
 * Politics of Fear: Beyond Left and Right (2005), by Frank Furedi, ISBN 0-8264-8728-9
 * You Have the Power: Choosing Courage in a Culture of Fear (2005), by Frances Moore Lappe and Jeffrey Perkins, ISBN 978-1-58542-424-5
 * Urban Nightmares: The Media, the Right and the Moral Panic over the City (2006), by Steve Macek, ISBN 0-8166-4361-X
 * Cultures of Fear: A Critical Reader (2009), by Uli Linke, Danielle Smith, Anthropology, Culture and Society, ISBN 978-0-7453-2965-9
 * Social Theory of Fear: terror, torture and death in a post Capitalist World (2010), by Geoffrey Skoll, New York, Palgrave MacMillan ISBN 978-0-230-10349-8
 * Witnesses to Terror (2012), by Luke Howie, Baskinstoke, Palgrave MacMillan ISBN 978-0-8232-2434-0

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Culture of fear


text:
Devin the Dude

Devin Derico Copeland (born June 4, 1970), better known by his stage name Devin the Dude, is an American rapper known for his unique rapping style and his 2002 songs "Lacville '79" and "Doobie Ashtray" (sometimes "Doubie Ashtray").

Early life
Devin Copeland was born in Pontiac, Michigan on June 4, 1970. He spent most of his early childhood in St. Petersburg, Florida and moved to Houston, Texas while in the fourth grade. He spent the rest of his youth moving back and forth between New Boston and Houston, finally settling in Houston after graduating from high school. He smoked marijuana for the first time at a skating rink in seventh grade; marijuana later became a major influence on his music. As a teenager, Copeland became interested in breakdancing, joining several dance crews until he began rapping, which soon became his main interest. After graduating from high school, he met Rob Quest, a rapper, and record producer Jugg Mugg. The trio formed the group the Odd Squad.

Musical career
After forming the Odd Squad (later known as the Coughee Brothaz), the group signed to Rap-A-Lot Records. The label is notable for being the home of hip-hop artists such as Geto Boys, Scarface, and Too Much Trouble. Copeland moved on to become part of Scarface's Facemob before going solo in 1998. Copeland has released ten solo albums: The Dude (1998), Just Tryin' ta Live (2002), To tha X-Treme (2004), Waitin' to Inhale (2007), Landing Gear (2008), Suite 420 (2010), Gotta Be Me (2010), One for the Road (2013), Acoustic Levitation (2017) and Still Rollin' Up: Somethin' To Ride With (2019). He also made a number of guest appearances, including on Dr. Dre's "Fuck You" in 1999, De La Soul's "Baby Phat" in 2001, Slim Thug's "I'm Back" off of Boss of All Bosses in 2009, Gucci Mane's "Kush Is My Cologne" of off The State vs Radric Davis in 2009 alongside Bun B & E-40, Tech N9ne's "After Party" in 2010 off of The Gates Mixed Plate, and Young Jeezy's "Higher Learning" off of the late 2011 album Thug Motivation 103: Hustlerz Ambition.

In 2007, he appeared in a documentary titled Screwed In Houston produced by VBS/Vice Magazine that details the history of the Houston rap scene.

In 2008, he ended his 15-year relationship with Houston-based Rap-A-Lot Records after he decided not to renew his contract. Later that year, he signed with indie label Razor & Tie. Devin is currently being distributed by E1 Entertainment, formerly Koch. In 2012 Devin starred in the stoner comedy Highway, in which two pot smoking buddies go on a quest to find the best bud in the country on the legendary Highway 420. The soundtrack featured songs by 2 Chainz, UGK, Smoke DZA, Tha Dogg Pound, Slim Thug, Curren$y, David Banner, Asher Roth and more. On June 24, 2013, Devin announced that his eighth studio album would be titled One for the Road and be released in September 2013. It was later confirmed for an October 8, 2013, release.

Reception
Despite being a critical success, Devin the Dude has not achieved mainstream success. The New York Times has called him "A brilliant oddball with a spaced-out flow." In addition, he has been called "Rap's best-kept secret" and "Your favorite rapper's favorite rapper".

title: Devin the Dude


text: Wikipedia:Articles for deletion/Log/2005 February 26


text:
Premio Nadal

Premio Nadal is a Spanish literary prize awarded annually by the publishing house Ediciones Destino, part of Planeta. It has been awarded every year on 6 January since 1944. The Josep Pla Award for Catalan literature is given at the same ceremony.

The current monetary award stand at €18,000 for the winner; since 2010 the award does not choose or recognize a runner-up. It is one of the oldest and most prestigious Spanish literary awards.

Winners
List of Premio Nadal winners since the award was established:

 * 1944: Carmen Laforet for Nada
 * 1945: José Félix Tapia for La Luna ha entrado en casa
 * 1946: José María Gironella for Un hombre
 * 1947: Miguel Delibes for La sombra del ciprés es alargada
 * 1948: Sebastián Juan Arbó for Sobre las piedras grises
 * 1949: José Suárez Carreño for Las últimas horas
 * 1950: Elena Quiroga for Viento del Norte
 * 1951: Luis Romero for La noria
 * 1952: Dolores Medio for Nosotros, los Rivero
 * 1953: Lluïsa Forrellad for Siempre en capilla
 * 1954: Francisco José Alcántara for La muerte le sienta bien a Villalobos
 * 1955: Rafael Sánchez Ferlosio for El Jarama
 * 1956: José Luis Martín Descalzo for La frontera de Dios
 * 1957: Carmen Martín Gaite for Entre visillos
 * 1958: José Vidal Cadellans for No era de los nuestros
 * 1959: Ana María Matute for Primera memoria
 * 1960: Ramiro Pinilla for Ciegas hormigas
 * 1961: Juan Antonio Payno for El curso
 * 1962: José María Mendiola for Muerte por fusilamiento
 * 1963: Manuel Mejía Vallejo for El día señalado
 * 1964: Alfonso Martínez Garrido for El miedo y la esperanza
 * 1965: Eduardo Caballero Calderón for El buen salvaje
 * 1966: Vicente Soto for La zancada
 * 1967: José María Sanjuán for Réquiem por todos nosotros
 * 1968: Álvaro Cunqueiro for Un hombre que se parecía a Orestes
 * 1969: Francisco García Pavón for Las hermanas coloradas
 * 1970: Jesús Fernández Santos for Libro de las memorias de las cosas
 * 1971: José María Requena for El cuajarón
 * 1972: José María Carrascal for Groovy
 * 1973: José Antonio García Blázquez for El rito
 * 1974: Luis Gasulla for Culminación de Montoya
 * 1975: Francisco Umbral for Las ninfas
 * 1976: Raúl Guerra Garrido for Lectura insólita de "El Capital"
 * 1977: José Asenjo Sedano for Conversación sobre la guerra
 * 1978: Germán Sánchez Espeso for Narciso
 * 1979: Carlos Rojas for El ingenioso hidalgo y poeta Federico García Lorca asciende a los infiernos
 * 1980: Juan Ramón Zaragoza for Concerto grosso
 * 1981: Carmen Gómez Ojea for Cantiga de agüero
 * 1982: Fernando Arrabal for La torre herida por el rayo
 * 1983: Salvador García Aguilar for Regocijo en el hombre
 * 1984: José Luis de Tomás for La otra orilla de la droga
 * 1985: Pau Faner Coll for Flor de sal
 * 1986: Manuel Vicent for Balada de Caín
 * 1987: Juan José Saer for La ocasión
 * 1988: Juan Pedro Aparicio for Retratos de ambigú
 * 1989: Not awarded
 * 1990: Juan José Millás for La soledad era esto
 * 1991: Alfredo Conde for Los otros días
 * 1992: Alejandro Gándara for Ciegas esperanzas
 * 1993: Rafael Argullol for La razón del mal
 * 1994: Rosa Regàs for Azul
 * 1995: Ignacio Carrión for Cruzar el Danubio
 * 1996: Pedro Maestre Herrero for Matando dinosaurios con tirachinas
 * 1997: Carlos Cañeque for Quién
 * 1998: Lucía Etxebarria for Beatriz y los cuerpos celestes
 * 1999: Gustavo Martín Garzo for Las historias de Marta y Fernando
 * 2000: Lorenzo Silva for El alquimista impaciente
 * 2001: Fernando Marías Amondo for El niño de los coroneles
 * 2002: Ángela Vallvey for Los estados carenciales
 * 2003: Andrés Trapiello for Los amigos del crimen perfecto
 * 2004: Antonio Soler for El camino de los ingleses
 * 2005: Pedro Zarraluki for Un encargo difícil
 * 2006: Eduardo Lago for Llámame Brooklyn
 * 2007: Felipe Benítez Reyes for Mercado de espejismos
 * 2008: Francisco Casavella for Lo que sé de los vampiros
 * 2009: Maruja Torres for Esperadme en el cielo
 * 2010: Clara Sanchez for Lo que esconde tu nombre
 * 2011: Alicia Giménez Bartlett for Donde nadie te encuentre
 * 2012: Álvaro Pombo for El temblor del héroe
 * 2013: Sergio Vila-Sanjuán for Estaba en el aire
 * 2014: Carmen Amoraga for La vida era eso
 * 2015: José C. Vales for Cabaret Biarritz
 * 2016: Víctor del Árbol for La víspera de casi todo
 * 2017: Care Santos for Media vida
 * 2018: Alejandro Palomas for Un amor
 * 2019: Guillermo Martínez for Los crímenes de Alicia
 * 2020: Ana Merino for El mapa de los afectos
 * 2021: Najat El Hachmi for El lunes nos querrán
 * 2022: Inés Martín Rodrigo for Las formas del querer
 * 2023: Manuel Vilas for Nosotros
 * 2024: César Pérez Gellida for Bajo tierra seca

Runners-up
List of runners-up (finalistas) of Premio Nadal since the award was instituted:

 * 1944: José María Álvarez Blázquez for En el pueblo hay caras nuevas
 * 1945: Francisco García Pavón for Cerca de Oviedo
 * 1946: Eulalia Galvarriato for Cinco sombras and Luis Manteiga for Un hombre à la deriva
 * 1947: Ana María Matute for Los Abel, Rosa María Cajal for Juan Risco and Juan Manuel Pombo Angulo for Hospital General
 * 1948: Manuel Mur Oti for Destino negro and Antonio Rodríguez Huescar for Vida con una diosa
 * 1949: Carlos de Santiago for El huerto de Pisadiel
 * 1950: Francisco Montero Galvache for El mar está solo
 * 1951: Tomás Salvador for Historias de Valcanillo, José María Jové for Mientras llueve en la tierra and José Antonio Giménez Arnau for De pantalón largo
 * 1952: Severiano Fernández Nicolás for La ciudad sin horizonte and Vicente Risco for La puerta de paja
 * 1953: Alejandro Núñez Alonso for La gota de mercurio
 * 1954: Ángel Oliver for Días turbulentos
 * 1955: Héctor Vázquez Azpiri for Víbora
 * 1956: Jesús López Pacheco for Central eléctrica
 * 1957: Lauro Olmo for Ayer, 27 de octubre
 * 1958: Claudio Bassols for El carnaval de los gigantes
 * 1959: Armando López Salinas for La mina
 * 1960: Gonzalo Torrente Malvido for Hombres varados
 * 1961: Pedro Antoñana for La cuerda rota
 * 1962: Manuel Barrios for El crimen
 * 1963: Mariano Viguera for Coral
 * 1964: Manuel Barrios for La espuela
 * 1965: Juan Farias for Los buscadores de agua
 * 1966: Carmelo M. Lozano for Gambito de alfil de rey
 * 1967: Francisco García Pavón for El reinado de Witiza
 * 1968: Eduardo García for Sede vacante
 * 1969: Luis Ricardo Alonso for El candidato
 * 1970: Gabriel García-Badell for De las Armas de Montemolín
 * 1971: Gustavo Álvarez de Gardeazábal for Dabeiba
 * 1972: Gabriel García-Badell for Las cartas cayeron boca abajo and Bernardo Víctor Carande for Suroeste
 * 1973: Gabriel García-Badell for Funeral por Francia y Aquilino Duque for El mono azul
 * 1974: Guillermo Ariel Ramón Carrizo for Crónica sin héroes
 * 1975: Manuel Villar Raso for Mar ligeramente Sur
 * 1976: Emilio Mansera Conde for La crisopa
 * 1977: Gabriel García-Badell for La zarabanda
 * 1978: Manuel Vicent for El anarquista coronado con adelfas and Rocío Vélez de Piedrahita for Terrateniente
 * 1979: Manuel Vicent for Ángeles o neófitos and Gabriel García-Badell for Nuevo auto de fe
 * 1980: Ramón Eiroa for Notas para la aclaración de un suicidio and Jorge González Aranguren for En otros parques donde estar ardiendo
 * 1981: Alfonso Zapater for El accidente and Juan Luis González Ripoll for El dandy del lunar
 * 1982: José Luis Aguirre for La excursión
 * 1983: José Avello Flórez for La subversión de Beti García
 * 1984: Telmo Herrera for Papá murió hoy
 * 1985: Vicente Sánchez Pinto for Los desiertos del amor
 * 1986: Horacio Vázquez-Rial for Historia del Triste and Rafael Humberto Moreno-Durán for Los felinos del Canciller
 * 1987: José Ferrater Mora for El juego de la verdad
 * 1988: Jesús Carazo for Los límites del paraíso
 * 1989: Not awarded
 * 1990: Pedro Crespo García for El cuaderno de Forster
 * 1991: Mariano Arias for El silencio de las palabras
 * 1992: Jesús Díaz for Las palabras perdidas
 * 1993: Jorge Ordaz for La perla del Oriente
 * 1994: José Ángel Mañas for Historias del Kronen
 * 1995: Félix Bayón for Adosados
 * 1996: Juana Salabert for Arde lo que será
 * 1997: Lorenzo Silva for La flaqueza del bolchevique
 * 1998: Ignacio García-Valiño for La caricia del escorpión
 * 1999: Lilian Neuman for Levantar ciudades
 * 2000: José Carlos Somoza for Dafne desvanecida
 * 2001: Lola Beccaria for La luna en Jorge
 * 2002: José Luis de Juan for Kaleidoscopio
 * 2003: David Torres for El gran silencio
 * 2004: Javier Puebla for Sonríe Delgado
 * 2005: Nicolás Casariego for Cazadores de luz
 * 2006: Marta Sanz for Susana y los viejos
 * 2007: Carmen Amoraga for Algo tan parecido al amor
 * 2008: Eva Díaz Pérez for El Club de la Memoria
 * 2009: Rubén Abella for El libro del amor esquivo
 * 2013: Esteban Navarro for La noche de los peones

title: Premio Nadal


text:
Croatian-North American Soccer Tournament

The Croatian-North American Soccer Tournament is a soccer tournament established in 1964 featuring teams representing the Croatian Canadian and Croatian American communities. It is organized by the Croatian National Soccer Federation of Canada & the U.S., and hosted annually by a CNSF member club.

It is traditionally played on the Labour Day weekend to accommodate teams who have to travel long distances. There is no prize money for winning the tournament. The event attracts large Croatian crowds and is intended to allow each host club to gain financially so that they can maintain stability and promote their Croatian name and heritage in their own cities.

The dynasties of the competition are Toronto Croatia and Chicago CBP. Similar tournaments for Croatian diaspora teams are held in the west coast of North America and in Australia.

Tournament winners

 * Chicago CBP, 16 titles
 * Toronto Croatia, 13 titles
 * Hrvat Chicago, 7 titles
 * Cleveland Croatia, 5 titles
 * Hamilton Croatia, 2 titles
 * Chicago Zrinski, 2 title
 * Kitchener Hrvat, 1 title
 * London Croatia, 1 title
 * Oakville Velebit, 1 title
 * Windsor Croatia, 1 title
 * Vancouver Croatia, 1 title
 * Cleveland Zagreb, 1 title
 * New York Croatia, 1 title
 * Streetsville Dalmacija, 1 title


text:
Military Collegium of the Supreme Court of the Soviet Union

The Military Collegium of the Supreme Court of the Soviet Union (Russian: Военная коллегия Верховного суда СССР, Voennaya kollegiya Verkhovnogo suda SSSR) was created in 1924 by the Supreme Court of the Soviet Union as a court for the higher military and political personnel of the Red Army and Fleet. In addition it was an immediate supervisor of military tribunals and the supreme authority of military appeals.

During 1926–1948 the Chairman of the Collegium was Vasiliy Ulrikh.

The role of the Military Collegium drastically changed after June 1934, when it was assigned the duty to consider cases that fell under Article 58, counter-revolutionary activity.

During the Great Purge of 1937–1938 the Military Collegium tried relatively prominent figures, usually based on the lists approved personally by Joseph Stalin, the majority of Article 58 cases having been processed extrajudicially by NKVD troikas. In particular, the Military Collegium conducted the major Soviet show trials.

The Collegium was also involved in a subsequent trial of Polish General Leopold Okulicki, the last commander of the Polish Home Army, and Jan Stanisław Jankowski, Government Delegate for Poland.

Chairmen

 * 1923–1926: Valentin Trifonov
 * 1926–1948: Vasiliy Ulrikh
 * 1948–1957: Aleksandr Cheptsov
 * 1957–1964: Viktor Borisoglebskiy
 * 1964–1971: Nikolay Chistyakov


text:
Talk:American Railway Union

Untitled
Changed a sentence to read "first and only victory," from "first, and unfortunately only, victory" which is pov. Paul 23:09, 25 Feb 2005 (UTC)

Comment
I moved this comment here from the article page. The American Railway Union was not the first industrial union in America. Both the United Mineworkers of America and the United Brewery Workers used the industrial form of organization from the mid-19th centruty onward. Rich Klimmer141.156.180.149 09:52, 24 October 2006 (UTC) --Bookandcoffee 17:44, 24 October 2006 (UTC)

title: Talk:American Railway Union


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File:ThatGangofMine.JPG

Fair use in That Gang of Mine
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 * 1) It's a low resolution copy of a Film Poster / VHS or DVD Cover.
 * 2) It doesn't limit the copyright owner's rights to sell the film in any way, in fact, it may encourage sales.
 * 3) Because of the low resolution, copies could not be used to make illegal copies of the artwork/image.
 * 4) The image is itself a subject of discussion in the article or used in the infobox thereof.
 * 5) The image  is significant because it was used to promoted a notable film.

Source

 * 1) Derived from a digital capture (photo/scan) of the Film Poster/ VHS or DVD Cover (creator of this digital version is irrelevant as the copyright in all equivalent images is still held by the same party). Copyright held by the film company or the artist.  Claimed as fair use regardless.

title: File:ThatGangofMine.JPG


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User talk:Nortonew

Welcome!

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Image Tagging Image:Ypotryll.gif
Thanks for uploading Image:Ypotryll.gif. I notice the image page currently doesn't specify who created the image, so the copyright status is therefore unclear. If you have not created the image yourself then you need to argue that we have the right to use the image on Wikipedia (see copyright tagging below). If you have not created the image yourself then you should also specify where you found it, i.e., in most cases link to the website where you got it, and the terms of use for content from that page.

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Wikipedia_talk:Censorship
A watered-down version of the proposed policy against censorship is now open for voting. Will you kindly review the policy and make your opinions known? Thank you very much. Loom91 12:41, 5 April 2006 (UTC)

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Proposed deletion of World ufo day
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Articles for deletion nomination of World ufo day
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July 2013
Hello, I'm Doniago. I noticed that you made a change to an article, Rogue wave, but you didn't provide a reliable source. It's been removed for now, but if you'd like to include a citation and re-add it, please do so! If you think I made a mistake, or if you have any questions, you can leave me a message on my talk page. Thank you. -- DonIago (talk) 16:56, 10 July 2013 (UTC)

title: User talk:Nortonew


text: User talk:70.241.109.62

title: User talk:70.241.109.62


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Mount Macdonald Tunnel

The Mount Macdonald Tunnel is in southeastern British Columbia, on the Revelstoke–Donald segment. This single-track 9.11 mi tunnel, which carries the Canadian Pacific Kansas City (CPKC) main line under Mount Macdonald in the Selkirk Mountains, handles most westbound traffic, whereas the Connaught Tunnel handles mostly eastbound. The tunnel was opened by the Canadian Pacific Railway (CP) in 1988.

Shortcomings of the Connaught Track
By the 1970s, it was evident that the Connaught Tunnel alone could not meet the increasing traffic demands. The major growth opportunities were primarily in the bulk commodities of coal, sulfur, and potash. In 1980, the estimated construction cost of $300 million was almost 20% of CP's gross income for 1979. Furthermore, westbound grain transportation had been an ongoing liability for the railways. Consequently, CP was unwilling to proceed with a new tunnel unless the Crow Rate, which did not cover the variable cost of grain movement, was addressed. In response, the federal government gradually increased this rate from 1983, before abandoning rate regulation in 1993.

The need for pusher locomotives was another encumbrance. During the pusher station's existence, six engineers, six maintenance workers, and nine locomotives, were based at Rogers. Five-unit engines were used on heavy trains carrying grain, coal, and potash. Four-unit engines were used on other freights. A significant grade improvement would eliminate the need for pushers.

Proposals
To enable the reintroduction of double tracks, three schemes required a 6 ft lowering of the Connaught Tunnel floor, complemented by a new approach to serve the east portal: However, lowering the floor would be extremely difficult while maintaining traffic flow.
 * south side of the Beaver Valley with a loop up to the portal.
 * higher than the existing track, requiring higher bridges over the five major streams, before levelling to the portal.
 * below the existing track from Rogers with 1.0% grade to Stoney Creek, followed by two 1 mi spiral tunnels up to the portal.

Three schemes offered a straight new tunnel at a lower elevation: Mike Wakely, Regional Engineer, Special Projects, suggested the selected option, which provided a 1.0% grade from Rogers, and a west portal 3.0 mi west of Glacier station. The budget, including approaches, was $600 million. In 1975, preparatory work began in earnest.
 * approximating the 9.1 mi tunnel as built.
 * a 9.8 mi tunnel from about the chosen west portal to about the Mount Shaughnessy Tunnel south portal.
 * a 7.7 mi tunnel from about 250 m west of Loop Creek to about the chosen east portal.

Macdonald Track
The 21.6 mi route of surface track and tunnels, within a 100 ft wide right-of-way, uses continuous welded rail.

. Connaught Track and Macdonald Track diverge; named for former Pacific Region V.P.; previously called Rogers.

. Length: 130 ft; two span; double track; Cana Construction completed in July 1984.

. Connaught Track had to be moved 30 ft into the mountainside along this section to accommodate the new lower track.

. Length: 315 ft; 2 X 250-ton spans. Height: about 145 ft below Mountain Creek bridge on Connaught Track. Cana Construction completed in fall 1985.

. A 8800 ft siding; named after Mike Wakely, a former chief construction engineer, who oversaw the years of preparatory work, but retired before the work was properly underway, and died soon after, never to see the completed project.

. Length: 700 ft; seven spans. Height: about 500 ft below Stoney Creek bridge on Connaught Track.

. Length: 4032 ft; Pitts Engineering Construction began work in 1985; 45 X 89 ft steel spans, each weighing 82 tonnes; brought from Calgary via the Crowsnest Pass, because too wide for the Spiral Tunnels, and unloaded at the south end of the new Stoney Creek bridge; supported on 44 custom-designed piers and two abutments; pier heights range from 15 ft to 70 ft; cut and fill not adopted because it would undermine Connaught Track above, and encroach on highway below; spans installed from early 1987 to that July; walkway on north side; named after John Fox.

. Length 1.14 mi.

. Length 156 ft; single span; comprises a pair of 70-ton deck plate girders, offloaded near the east portal of the Connaught Tunnel, and hauled up to the highway and down to the site; Cana Construction built.

. A railway point.

. A railway point.

Construction

CP built a substation in Revelstoke and from it constructed a 35 kV operating distribution line along the railway right-of-way; originally built using both 69 kV insulators and construction standards.

On August 27, 1984, the Selkirk Construction joint venture (comprising S.A. Healey, Foundation Company of Canada, and Atlas Construction) began blasting from the east portal. By mid-October, sufficient room existed to install their 22 ft, 60 ft tunnel-boring machine (TBM). In December 1985, the tunnel passed 360 ft below the Connaught one, almost directly beneath the mountain peak. On completion, Selkirk Construction had advanced 5.25 mi westward.

On October 5, 1984, the Manning-Kumagai (MK) joint venture (comprising Manning Construction and Kumagai Gumi) began from the west portal. Using the drilling and blasting method, 30 men, rostered in 3 shifts, completed 3.6 mi eastward. Meanwhile, the highway was temporarily relocated to construct a 880 ft reinforced concrete box in a cut-and-cover trench. This structure carries both the highway and protects the portal from avalanches. In 1985, the words "Mount Macdonald Tunnel 1988" were stamped into the concrete cladding above the portal. The eastern work camp was near the Mount Shaughnessy Tunnel, and the western one at Flat Creek. A third camp for summer surface workers existed near Rogers.

Breaking through on October 24, 1986, the approaching tunnels joined. Cementation Canada sank the 28 ft, 1150 ft ventilation shaft. MK drilled and blasted the gate chamber below, and air tunnels to, this shaft. After concrete lining, the tunnel height is 25 ft, and the width is 17 ft on the straights, and 18 ft on the curves. In September 1988, the final track concrete was poured. The paved concrete track (PaCT) rests on a 7 ft, 9 in reinforced concrete slab. The height clearance can accommodate any future electrification.

A fleet of 50 dump cars were built exclusively for the project. About 5,000 tons of material were removed daily from the western side. Parks Canada allowed some dumping about 2.8 mi from the portal, creating a bed for track twinning. The remainder was dumped outside the park boundary at various proposed double-tracking sites between Golden and Revelstoke. The 660 cuyd of rubble produced daily at the eastern end was dumped into a large depression to create the grade. Minus the 156 ft bridge, this fill covered the 4386 ft distance to the Mount Shaughnessy Tunnel.

Tunnel ventilation
Because of the tunnel's length and lack of electrification, it uses a ventilation system consisting of a series of huge fans which clear the tunnel of diesel exhaust left behind by the locomotives. The tunnel also has large doors at the portals and the mid-point which can open and close whenever the tunnel needs to be cleared out.

The purpose of the ventilation system is to prevent locomotives overheating and remove air pollutants. The opening and closing of the gates at the portals and mid-point assists the extraction process. The mid-tunnel gate structure stands inside a 82 ft, 88 ft, and 52 ft cavern. In a power failure, counterweights return all gates to the up position. Each gate has a central wooden panel designed to break if struck by a train. Although monitored at the Revelstoke control centre, the ventilation system is computer controlled, and adjusts to the type and size of train. Standing at the top of the shaft, near the Rogers Pass highway summit, the ventilation building houses four fans, a standby 3,800 hp diesel generator, and two elevators. Used by maintenance staff, each open cage takes $11 1/2$ minutes to slowly descend an open elevator shaft to tunnel level. A straight tunnel would have made the shaft location clearly visible from the summit monument. To hide the complex, a slight kink was made in the tunnel alignment.

Operation
On November 9, 1988, the first official train travelled the Macdonald Track westward. About 535 m west of the west portal, R.S Allison, CP president, connected the last track clip. On December 12, 1988, the first revenue train, hauling coal, passed through the tunnel, and saved an hour on the journey. The official opening of the $422 million tunnel was in May 1989. The crest at the west portal is 295 ft lower than the Connaught crest. The 0.7% gradient westward eliminated the need for pusher locomotives. Nowadays, locomotives can climb the grade at 20 mph. Loaded coal trains travel at 9 to 13 mph through the tunnel. To ensure frequency vibrations do not cause damage to the track structure, the speed limit for all traffic is 30 mph.

Maintenance
CP repairs 50 to 200 ft of PaCT each year. Drain holes cored down to a longitudinal collector drain under the tunnel reduce failures from excessive surface water. Slab cracking, owing to insufficient lateral and longitudinal reinforcing in the PaCT slab, can be repaired with epoxy resin in minor cases. Injecting the resin restores structural integrity. Slab removal and replacement is needed in serious cases. From 1993 to 2020, a total of 378 ft of PaCT were replaced in the two tunnels.

The hardware for power, communications, and signalling is obsolete. The slow ventilation systems can take 45 minutes to purge the air after each train. In 2019, consultants were advising on possible improvements, but it will probably take 5 to 10 years to modernize the tunnel.

Notability
Twelfth longest railway tunnel when opened:

Seikan Tunnel (1988) (Japan) 53.85 km

Daishimizu Tunnel (1982) (Japan) 22.20 km

Simplon Tunnel (1906) (Switzerland) 19.80 km

Shin Kanmon Tunnel (1975) (Japan) 18.71 km

Apennine Base Tunnel (1934) (Italy) 18.51 km

Rokkō Tunnel (1972) 16.25 km

Furka Base Tunnel (1982) (Switzerland) 15.44 km

Haruna (1982) 15.35 km

Monte Santomarco Tunnel (1987) (Italy) 15.04 km

Gotthard Tunnel (1882) (Switzerland) 15.00 km

Nakayama (1982) 14.86 km

Mount Macdonald Tunnel (1988) 14.66 km

However, it took the title from the Cascade Tunnel (1929) 12.6 km as the longest railway tunnel in the North America. The project was the largest CP expansion of capacity since the building of the transcontinental in the early 1880s. In 2016, the tunnel was inducted into the North America Railway Hall of Fame. Tunnel 4 of the Cuajone–El Sargento line in Peru is of similar length, and which is the longer of the two is disputed.

Accidents
2005: While clearing ice in the tunnel, an employee died when struck by a falling 225 kg chunk.

2019: An avalanche descending upon a stopped train at Wakely derailed seven container-carrying flatcars.

title: Mount Macdonald Tunnel