Oxygen Demand

	Oxygen Demand Oxygen demand is an environmental chemistry term that may refer to: Biochemical oxygen demand (BOD), the amount of oxygen needed by organisms to break down organic material present in a water sample Carbonaceous biochemical oxygen demand (CBOD), the amount of oxygen needed to break down carbon compounds, excluding nitrogen compounds * Chemical and biological oxygen demand, the combination of biochemical (BOD) and chemical oxygen demand (COD) 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, wh ... (COD), a test commonly used to indirectly measure the amount of organic compounds in a water sample Nitrogenous oxygen demand (NOD), the amount of oxygen required to break down nitrogenous compounds in a water sample, like ammonia * Theoretical oxygen demand (ThOD), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Biochemical Oxygen Demand Biochemical oxygen demand (also known as BOD or biological oxygen demand) is an analytical parameter representing the amount of dissolved oxygen (DO) consumed by aerobic bacteria growing on the organic material present in a water sample at a specific temperature over a specific time period. The BOD value is most commonly expressed in milligrams of oxygen consumed per liter of sample during 5 days of incubation at 20 °C and is often used as a surrogate of the degree of organic water pollution. Biochemical Oxygen Demand (BOD) reduction is used as a gauge of the effectiveness of wastewater treatment plants. BOD of wastewater effluents is used to indicate the short-term impact on the oxygen levels of the receiving water. BOD analysis is similar in function to chemical oxygen demand (COD) analysis, in that both measure the amount of organic compounds in water. However, COD analysis is less specific, since it measures everything that can be chemically oxidized, rather than j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Chemical And Biological Oxygen Demand A chemical substance is a unique form of matter with constant chemical composition and characteristic properties. Chemical substances may take the form of a single element or chemical compounds. If two or more chemical substances can be combined without reacting, they may form a chemical mixture. If a mixture is separated to isolate one chemical substance to a desired degree, the resulting substance is said to be chemically pure. Chemical substances can exist in several different physical states or phases (e.g. solids, liquids, gases, or plasma) without changing their chemical composition. Substances transition between these phases of matter in response to changes in temperature or pressure. Some chemical substances can be combined or converted into new substances by means of chemical reactions. Chemicals that do not possess this ability are said to be inert. Pure water is an example of a chemical substance, with a constant composition of two hydrogen atoms bonded to a sin ... [...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 liter ( mg/ L). A COD test can be used to quickly 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Nitrogenous Oxygen Demand Nitrogen is a chemical element; it has symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at seventh in total abundance in the Milky Way and the Solar System. At standard temperature and pressure, two atoms of the element bond to form N2, a colourless and odourless diatomic gas. N2 forms about 78% of Earth's atmosphere, making it the most abundant chemical species in air. Because of the volatility of nitrogen compounds, nitrogen is relatively rare in the solid parts of the Earth. It was first discovered and isolated by Scottish physician Daniel Rutherford in 1772 and independently by Carl Wilhelm Scheele and Henry Cavendish at about the same time. The name was suggested by French chemist Jean-Antoine-Claude Chaptal in 1790 when it was found that nitrogen was present in nitric acid and nitrates. Antoine Lavoisier suggested instead the name ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]