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Expanded Granular Sludge Bed Digestion
An expanded granular sludge bed (EGSB) reactor is a variant of the upflow anaerobic sludge blanket digestion (UASB) concept for anaerobic wastewater treatment. The distinguishing feature is that a faster rate of upward-flow velocity is designed for the wastewater passing through the sludge bed. The increased flux permits partial expansion (fluidisation) of the granular sludge bed, improving wastewater-sludge contact as well as enhancing segregation of small inactive suspended particle from the sludge bed. The increased flow velocity is either accomplished by utilizing tall reactors, or by incorporating an effluent recycle (or both). A scheme depicting the EGSB design concept is shown in thiEGSB diagram The EGSB design is appropriate for low strength soluble wastewaters (less than 1 to 2 g soluble COD/l) or for wastewaters that contain inert or poorly biodegradable suspended particles which should not be allowed to accumulate in the sludge bed. See also *Anaerobic digester types * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upflow Anaerobic Sludge Blanket Digestion
Upflow anaerobic sludge blanket (UASB) technology, normally referred to as UASB reactor, is a form of anaerobic digester that is used for wastewater treatment. The UASB reactor is a methanogenic (methane-producing) digester that evolved from the anaerobic clarigester. A similar but variant technology to UASB is the expanded granular sludge bed (EGSB) digester. Process description UASB uses an anaerobic process whilst forming a blanket of granular sludge which suspends in the tank. Wastewater flows upwards through the blanket and is processed (degraded) by the anaerobic microorganisms. The upward flow combined with the settling action of gravity suspends the blanket with the aid of flocculants. The blanket begins to reach maturity at around three months. Small sludge granules begin to form whose surface area is covered in aggregations of bacteria. In the absence of any support matrix, the flow conditions create a selective environment in which only those microorganisms capable of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 aci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Oxygen Demand
In environmental chemistry, the chemical oxygen demand (COD) is an indicative measure of the amount of oxygen that can be consumed by reactions in a measured solution. It is commonly expressed in mass of oxygen consumed over volume of solution which in SI units is milligrams per litre ( mg/ L). A COD test can be used to easily quantify the amount of organics in water. The most common application of COD is in quantifying the amount of oxidizable pollutants found in surface water (e.g. lakes and rivers) or wastewater. COD is useful in terms of water quality by providing a metric to determine the effect an effluent will have on the receiving body, much like biochemical oxygen demand (BOD). Overview The basis for the COD test is that nearly all organic compounds can be fully oxidized to carbon dioxide with a strong oxidizing agent under acidic conditions. The amount of oxygen required to oxidize an organic compound to carbon dioxide, ammonia, and water is given by: :\mbox_n\mbox_a\mb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anaerobic Digester Types
The following is a partial list of types of anaerobic digesters. These processes and systems harness anaerobic digestion for purposes such as treatment of biowaste, animal manure, sewage and biogas generation. Anaerobic digesters can be categorized according to several criteria: by whether the biomass is fixed to a surface ("attached growth") or can mix freely with the reactor liquid ("suspended growth"); by the organic loading rate (the influent mass rate of chemical oxygen demand per unit volume); by centralized plants and decentralized plants. Most anaerobic digesters worldwide are built based on wet-type anaerobic digestion, wherein biomass (usually animal dung) and water are mixed in equal amounts to form a slurry in which the content of total solids (TS) is about 10-15%. While this type is suitable for most regions, it becomes a challenge in large plants where it necessitates the use of large quantities of water every day, often in water-scare areas. Solid-state type digesters ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biogas
Biogas is a mixture of gases, primarily consisting of methane, carbon dioxide and hydrogen sulphide, produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste and food waste. It is a renewable energy source. Biogas is produced by anaerobic digestion with anaerobic organisms or methanogen inside an anaerobic digester, biodigester or a bioreactor. Biogas is primarily methane () and carbon dioxide () and may have small amounts of hydrogen sulfide (), moisture and siloxanes. The gases methane, hydrogen, and carbon monoxide () can be combusted or oxidized with oxygen. This energy release allows biogas to be used as a fuel; it can be used in fuel cells and for any heating purpose, such as cooking. It can also be used in a gas engine to convert the energy in the gas into electricity and heat. Biogas can be compressed after removal of carbon dioxide and hydrogen sulphide, the same way as natural gas is compressed to CN ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Wastewater Treatment Technologies
This page consists of a list of wastewater treatment technologies: See also *Agricultural wastewater treatment *Industrial wastewater treatment *List of solid waste treatment technologies * Waste treatment technologies *Water purification *Sewage sludge treatment Sewage sludge treatment describes the processes used to manage and dispose of sewage sludge produced during sewage treatment. Sludge treatment is focused on reducing sludge weight and volume to reduce transportation and disposal costs, and on red ... References * * Industrial Wastewater Treatment Technology DatabaseEPA. {{DEFAULTSORT:List Of Waste Water Treatment Technologies Chemical processes Environmental engineering *List Water pollution Water technology Waste-water treatment technologies Sanitation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Pollution
Water pollution (or aquatic pollution) is the contamination of water bodies, usually as a result of human activities, so that it negatively affects its uses. Water bodies include lakes, rivers, oceans, aquifers, reservoirs and groundwater. Water pollution results when contaminants are introduced into these water bodies. Water pollution can be attributed to one of four sources: sewage discharges, industrial activities, agricultural activities, and urban runoff including stormwater. It can be grouped into surface water pollution (either fresh water pollution or marine pollution) or groundwater pollution. For example, releasing inadequately treated wastewater into natural waters can lead to degradation of these aquatic ecosystems. Water pollution can also lead to water-borne diseases for people using polluted water for drinking, bathing, washing or irrigation. Water pollution reduces the ability of the body of water to provide the ecosystem services (such as drinking water) that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Environmental Engineering
Environmental engineering is a professional engineering discipline that encompasses broad scientific topics like chemistry, biology, ecology, geology, hydraulics, hydrology, microbiology, and mathematics to create solutions that will protect and also improve the health of living organisms and improve the quality of the environment. Environmental engineering is a sub-discipline of civil engineering and chemical engineering. While on the part of civil engineering, the Environmental Engineering is focused mainly on Sanitary Engineering. Environmental engineering is the application of scientific and engineering principles to improve and maintain the environment to: * protect human health, *protect nature's beneficial ecosystems, *and improve environmental-related enhancement of the quality of human life. Environmental engineers devise solutions for wastewater management, water and air pollution control, recycling, waste disposal, and public health. They design municipal water supply ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
