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Dewatering
Dewatering is the removal of water from a location. This may be done by wet classification, centrifugation, filtration, or similar solid-liquid separation processes, such as removal of residual liquid from a filter cake by a filter press as part of various industrial processes. Construction dewatering, unwatering, or water control are common terms used to describe removal or draining groundwater or surface water from a riverbed, construction site, caisson, or mine shaft, by pumping or evaporation. On a construction site, this dewatering may be implemented before subsurface excavation for foundations, shoring, or cellar space to lower the water table. This frequently involves the use of submersible "dewatering" pumps, centrifugal ("trash") pumps, eductors, or application of vacuum to well points. The international business research company Visiongain valued the global dewatering pump market at $6.4 billion in 2018. Processes Deep wells A deep well typically consists of a bor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filter Press
An industrial filter press is a tool used in separation processes, specifically to separate solids and liquids. The machine stacks many filter elements and allows the filter to be easily opened to remove the filtered solids, and allows easy cleaning or replacement of the filter media. Filter presses cannot be operated in a continuous process but can offer very high performance, particularly when low residual liquid in the solid is desired. Among other uses, filter presses are utilised in marble factories in order to separate water from mud in order to reuse the water during the marble cutting process. Concept behind filter press technology Generally, the slurry that will be separated is injected into the centre of the press and each chamber of the press is filled. Optimal filling time will ensure the last chamber of the press is loaded before the mud in the first chamber begins to cake. As the chambers fill, pressure inside the system will increase due to the formation of thick sl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Watertable Control
Watertable control is the practice of controlling the height of the water table by drainage. Its main applications are in agricultural land (to improve the crop yield using agricultural drainage systems) and in cities to manage the extensive underground infrastructure that includes the foundations of large buildings, underground transit systems, and extensive utilities (water supply networks, sewerage, storm drains, and underground electrical grids). Description and definitions Subsurface land drainage aims at controlling the water table of the groundwater in originally waterlogged land at a depth acceptable for the purpose for which the land is used. The depth of the water table with drainage is ''greater'' than without. Purpose In agricultural land drainage, the purpose of water table control is to establish a depth of the water table (Figure 1) that does no longer interfere negatively with the necessary farm operations and crop yields (Figure 2, made with the SegReg mode ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centrifugation
Centrifugation is a mechanical process which involves the use of the centrifugal force to separate particles from a solution according to their size, shape, density, medium viscosity and rotor speed. The denser components of the mixture migrate away from the axis of the centrifuge, while the less dense components of the mixture migrate towards the axis. Chemists and biologists may increase the effective gravitational force of the test tube so that the precipitate (pellet) will travel quickly and fully to the bottom of the tube. The remaining liquid that lies above the precipitate is called a supernatant or supernate. There is a correlation between the size and density of a particle and the rate that the particle separates from a heterogeneous mixture, when the only force applied is that of gravity. The larger the size and the larger the density of the particles, the faster they separate from the mixture. By applying a larger effective gravitational force to the mixture, like a ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pore Space
Porosity or void fraction is a measure of the void (i.e. "empty") spaces in a material, and is a fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0% and 100%. Strictly speaking, some tests measure the "accessible void", the total amount of void space accessible from the surface (cf. closed-cell foam). There are many ways to test porosity in a substance or part, such as industrial CT scanning. The term porosity is used in multiple fields including pharmaceutics, ceramics, metallurgy, materials, manufacturing, petrophysics, hydrology, earth sciences, soil mechanics, and engineering. Void fraction in two-phase flow In gas-liquid two-phase flow, the void fraction is defined as the fraction of the flow-channel volume that is occupied by the gas phase or, alternatively, as the fraction of the cross-sectional area of the channel that is occupied by the gas phase. Void fraction usually varies from location to location in the flow ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geotechnical Engineering
Geotechnical engineering is the branch of civil engineering concerned with the engineering behavior of earth materials. It uses the principles of soil mechanics and rock mechanics for the solution of its respective engineering problems. It also relies on knowledge of geology, hydrology, geophysics, and other related sciences. Geotechnical (rock) engineering is a subdiscipline of geological engineering. In addition to civil engineering, geotechnical engineering also has applications in military, mining, petroleum, coastal engineering, and offshore construction. The fields of geotechnical engineering and engineering geology have knowledge areas that overlap, however, while geotechnical engineering is a specialty of civil engineering, engineering geology is a specialty of geology: They share the same principles of soil mechanics and rock mechanics, but differ in the application. History Humans have historically used soil as a material for flood control, irrigation purposes, buria ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wastewater Treatment
Wastewater treatment is a process used to remove contaminants from wastewater and convert it into an effluent that can be returned to the water cycle. Once returned to the water cycle, the effluent creates an acceptable impact on the environment or is reused for various purposes (called water reclamation). The treatment process takes place in a wastewater treatment plant. There are several kinds of wastewater which are treated at the appropriate type of wastewater treatment plant. For domestic wastewater (also called municipal wastewater or sewage), the treatment plant is called a sewage treatment plant. For industrial wastewater, treatment either takes place in a separate industrial wastewater treatment plant, or in a sewage treatment plant (usually after some form of pre-treatment). Further types of wastewater treatment plants include agricultural wastewater treatment plants and leachate treatment plants. Processes commonly used in wastewater treatment include phase sepa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ejector Wells
An injector is a system of ducting and nozzles used to direct the flow of a high-pressure fluid in such a way that a lower pressure fluid is entrained in the jet and carried through a duct to a region of higher pressure. It is a fluid-dynamic pump with no moving parts except a valve to control inlet flow. A steam injector is a typical application of the principle used to deliver cold water to a boiler against its own pressure, using its own live or exhaust steam, replacing any mechanical pump. When first developed, its operation was intriguing because it seemed paradoxical, almost like perpetual motion, but it was later explained using thermodynamics. Other types of injector may use other pressurised motive fluids such as air. Depending on the application, an injector can also take the form of an ''eductor-jet pump'', a ''water eductor'' or an ''aspirator''. An ''ejector'' operates on similar principles to create a vacuum feed connection for braking systems etc. History The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pore Pressure
Pore water pressure (sometimes abbreviated to pwp) refers to the pressure of groundwater held within a soil or rock, in gaps between particles ( pores). Pore water pressures below the phreatic level of the groundwater are measured with piezometers. The vertical pore water pressure distribution in aquifers can generally be assumed to be close to hydrostatic. In the unsaturated ("vadose") zone, the pore pressure is determined by capillarity and is also referred to as tension, suction, or matric pressure. Pore water pressures under unsaturated conditions are measured with tensiometers, which operate by allowing the pore water to come into equilibrium with a reference pressure indicator through a permeable ceramic cup placed in contact with the soil. Pore water pressure is vital in calculating the stress state in the ground soil mechanics, from Terzaghi's expression for the effective stress of a soil. General principles Pressure develops due to: *''Water elevation differenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cofferdam Olmsted Locks Ohio River
A cofferdam is an enclosure built within a body of water to allow the enclosed area to be pumped out. This pumping creates a dry working environment so that the work can be carried out safely. Cofferdams are commonly used for construction or repair of permanent dams, oil platforms, bridge piers, etc., built within water. These cofferdams are usually welded steel structures, with components consisting of sheet piles, wales, and cross braces. Such structures are usually dismantled after the construction work is completed. The origin of the word comes from ''coffer'' (originally from Latin ''cophinus'' meaning "basket") and ''dam'' from Proto-German ''*dammaz'' meaning "barrier across a stream of water to obstruct its flow and raise its level"). Uses For dam construction, two cofferdams are usually built, one upstream and one downstream of the proposed dam, after an alternative diversion tunnel or channel has been provided for the river flow to bypass the foundation area of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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