|
Waste Compaction
Waste compaction is the process of compacting waste, reducing it in size. Garbage compactors and waste collection vehicles compress waste so that more of it can be stored in the same space. Waste is compacted again, more thoroughly, at the landfill to conserve valuable airspace and to extend the landfill's life span. Consumer and post-collection compaction Pre-landfill waste compaction is often beneficial, both for people disposing of waste and the company collecting it. This is because waste collection companies frequently charge by volume or require use of standard-volume containers, and compaction allows more waste to fit in the same space. Trash compactors are available for both residential and commercial use. Compacting garbage after it is collected allows more waste to fit inside the collection vehicle, meaning fewer trips to a dump or transfer station are required. The collection company also incurs lower landfill fees, if the landfill charges by volume. Landfill compa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waste
Waste are unwanted or unusable materials. Waste is any substance discarded after primary use, or is worthless, defective and of no use. A by-product, by contrast is a joint product of relatively minor Value (economics), economic value. A waste product may become a by-product, joint product or resource through an invention that raises a waste product's value above zero. Examples include municipal solid waste (household trash/refuse), hazardous waste, wastewater (such as sewage, which contains bodily wastes (feces and urine) and surface runoff), radioactive waste, and others. Definitions What constitutes waste depends on the eye of the beholder; one person's waste can be a resource for another person. Though waste is a physical object, its generation is a physical and psychological process. The definitions used by various agencies are as below. United Nations Environment Program According to the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Explosion
An explosion is a rapid expansion in volume of a given amount of matter associated with an extreme outward release of energy, usually with the generation of high temperatures and release of high-pressure gases. Explosions may also be generated by a slower expansion that would normally not be forceful, but is not allowed to expand, so that when whatever is containing the expansion is broken by the pressure that builds as the matter inside tries to expand, the matter expands forcefully. An example of this is a Volcano, volcanic eruption created by the expansion of magma in a magma chamber as it rises to the surface. Supersonic explosions created by high explosives are known as detonations and travel through shock waves. wikt:subsonic, Subsonic explosions are created by low explosives through a slower combustion process known as deflagration. Causes For an explosion to occur, there must be a rapid, forceful expansion of matter. There are numerous ways this can happen, both natura ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earthworks (engineering)
Earthworks are engineering works created through the processing of parts of the earth's surface involving quantities of soil or unformed rock (geology), rock. Shoring structures An incomplete list of possible temporary or permanent geotechnical engineering, geotechnical shoring structures that may be designed and utilised as part of earthworks: *Mechanically stabilized earth *Earth anchor *Cliff stabilization *Grout curtain *Retaining wall *Slurry wall *Soil nailing *Tieback (geotechnical) *Trench shoring *Caisson (engineering), Caisson *Dam *Gabion *Ground freezing Gallery File:Mechanically stabilized earth diagram.gif, Mechanically stabilized earth File:GroutCurtain.gif, Grout curtain File:Retaining Wall Type Function.jpg, Retaining wall types File:Soil Nail.jpg, Soil nailing File:FEMA - 6044 - Photograph by Larry Lerner taken on 03-15-2002 in New York.jpg, Tieback (geotechnical), Tieback File:Sbh s600.JPG, Trench shoring File:Caisson Schematic.svg, Caisson (engineering), Ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Runoff
Surface runoff (also known as overland flow or terrestrial runoff) is the unconfined flow of water over the ground surface, in contrast to ''channel runoff'' (or ''stream flow''). It occurs when excess rainwater, stormwater, meltwater, or other sources, can no longer sufficiently rapidly infiltrate in the soil. This can occur when the soil is #Saturation excess overland flow, saturated by water to its full capacity, and the rain arrives #Infiltration excess overland flow, more quickly than the soil can absorb it. Surface runoff often occurs because wikt:impervious#Adjective, impervious areas (such as roofs and Road surface, pavement) do not allow water to soak into the ground. Furthermore, runoff can occur either through natural or human-made processes. Surface runoff is a major component of the water cycle. It is the primary agent of Soil erosion#Rainfall and runoff, soil erosion by water. The land area producing runoff that drains to a common point is called a drainage basin. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soil Compaction
In geotechnical engineering, soil compaction is the process in which stress applied to a soil causes densification as air is displaced from the pores between the soil grains. When stress is applied that causes densification due to water (or other liquid) being displaced from between the soil grains, then consolidation (soil), consolidation, not compaction, has occurred. Normally, compaction is the result of heavy machinery compressing the soil, but it can also occur due to the passage of, for example, animal feet. In soil science and agronomy, soil compaction is usually a combination of both engineering compaction and consolidation, so may occur due to a lack of water in the soil, the applied stress being internal suction due to water evaporation as well as due to passage of animal feet. Affected soils become less able to absorb rainfall, thus increasing Runoff (water), runoff and erosion. Plants have difficulty in compacted soil because the mineral grains are pressed together, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biodegradation
Biodegradation is the breakdown of organic matter by microorganisms, such as bacteria and fungi. It is generally assumed to be a natural process, which differentiates it from composting. Composting is a human-driven process in which biodegradation occurs under a specific set of circumstances. The process of biodegradation is threefold: first an object undergoes biodeterioration, which is the mechanical weakening of its structure; then follows biofragmentation, which is the breakdown of materials by microorganisms; and finally assimilation, which is the incorporation of the old material into new cells. In practice, almost all chemical compounds and materials are subject to biodegradation, the key element being time. Things like vegetables may degrade within days, while glass and some plastics take many millennia to decompose. A standard for biodegradability used by the European Union is that greater than 90% of the original material must be converted into , water and minerals b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygenation (environmental)
Hypoxia (''hypo'': 'below', ''oxia'': 'oxygenated') refers to low oxygen conditions. Hypoxia is problematic for air-breathing organisms, yet it is essential for many anaerobic organisms. Hypoxia applies to many situations, but usually refers to the atmosphere and natural waters. Atmospheric hypoxia Atmospheric hypoxia occurs naturally at high altitudes. Total atmospheric pressure decreases as altitude increases, causing a lower partial pressure of oxygen, which is defined as hypobaric hypoxia. Oxygen remains at 20.9% of the total gas mixture, differing from hypoxic hypoxia, where the percentage of oxygen in the air (or blood) is decreased. This is common in the sealed burrows of some subterranean animals, such as blesmol The blesmols, also known as mole-rats, or African mole-rats, are burrowing rodents of the family Bathyergidae. They represent a distinct evolution of a Subterranean fauna, subterranean life among rodents much like the pocket gophers of North Am ...s. At ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pounds Per Square Inch
The pound per square inch (abbreviation: psi) or, more accurately, pound-force per square inch (symbol: lbf/in2), is a unit of measurement of pressure or of stress based on avoirdupois units and used primarily in the United States. It is the pressure resulting from a force with magnitude of one pound-force applied to an area of one square inch. In SI units, 1 psi is approximately . The pound per square inch absolute (psia) is used to make it clear that the pressure is relative to a vacuum rather than the ambient atmospheric pressure. Since atmospheric pressure at sea level is around , this will be added to any pressure reading made in air at sea level. The converse is pound per square inch gauge (psig), indicating that the pressure is relative to atmospheric pressure. For example, a bicycle tire pumped up to 65 psig in a local atmospheric pressure at sea level (14.7 psi) will have a pressure of 79.7 psia (14.7 psi + 65 psi). When gauge pressure is referenced to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Landfill Gas Migration
Landfill gas migration is a complex process in which gases produced by waste in a landfill move from the site of original deposition to other places via diffusion, usually from areas of high concentration to low. The process is also affected by the permeability of the ground and other factors, such as pressure differences in the soil, cavities, pipes, and tunnels. Changes in atmospheric pressure and the water table can encourage this migration. These gases can include methane (), carbon dioxide (), hydrogen (), and volatile organic compounds (there are approximately 500 others that can be present in trace forms) from the waste on site and its degradation over time. Steps must be taken to prevent this migration from the landfill site as it might enter buildings in the vicinity. This can be done on the site by means of combinations of geomembranes and clay based products, see gas protection. Gas protection Gas protection for buildings should consist of an impermeable gas mem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Landfill Gas
Landfill gas is a mix of different gases created by the action of microorganisms within a landfill as they decompose organic waste, including for example, food waste and paper waste. Landfill gas is approximately forty to sixty percent methane, with the remainder being mostly carbon dioxide. Trace amounts of other volatile organic compounds (VOCs) comprise the remainder (<1%). These trace gases include a large array of species, mainly simple s.Hans-Jürgen Ehrig, Hans-Joachim Schneider and Volkmar Gossow "Waste, 7. Deposition" in Ullmann's Encyclopedia of Industrial Chemistry, 2011, Wiley-VCH, Weinheim. Landfill gases have an influence on . The major components are [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cave-in
A cave-in is a collapse of a geologic formation, mine or structure which may occur during mining, tunneling, or steep-walled excavation such as trenching. Geologic structures prone to spontaneous cave-ins include alvar, tsingy and other limestone formations, but can also include lava tubes and a variety of other subsurface rock formations. Glacier caves and other ice formations are very prone to collapse from exposure to warm temperatures or running water. In mining, the term roof fall is used to refer to many types of collapses, ranging from the fall of a single flake of shale to collapses that form sink holes that reach to the surface. However, roof falls in mining are not all accidental. In longwall mining and retreat mining, miners systematically remove all support from under large areas of the mine roof, allowing it to settle just beyond the work area. The goal in such mining methods is not to prevent roof fall and the ensuing surface subsidence, but rather to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compactor
A compactor is a machine or mechanism used to reduce the size of material such as waste material or bio mass through compaction. A trash compactor is used in business and public places like hospitals (and in the United States also in homes) to reduce the volume of trash they produce. A baler-wrapper compactor is used for making compact and wrapped bales in order to improve logistics. Normally powered by hydraulics, compactors take many shapes and sizes. In landfill sites for example, a large tractor (typically a converted front end loader with some variant of a bulldozer blade attached) with spiked steel wheels called a landfill compactor is used to drive over waste deposited by waste collection vehicles (WCVs). WCVs themselves incorporate a compacting mechanism which is used to increase the payload of the vehicle and reduce the number of times it has to empty. This usually takes the form of hydraulically powered sliding plates which sweep out the collection hopper and co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
