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Biochemical oxygen demand is the amount of oxygen required for microbial metabolism of organic compounds in water. This demand occurs over some variable period of time depending on temperature, nutrient concentrations, and the enzymes available to indigenous microbial populations. The amount of oxygen required to completely oxidize the organic ...
The model describes how dissolved oxygen (DO) decreases in a river or stream along a certain distance by degradation of biochemical oxygen demand (BOD). The equation was derived by H. W. Streeter, a sanitary engineer, and Earle B. Phelps, a consultant for the U.S. Public Health Service, in 1925, based on field data from the Ohio River. The ...
Both have been widely adopted as a measure of pollution effect. The BOD test measures the oxygen demand of biodegradable pollutants whereas the COD test measures the oxygen demand of oxidizable pollutants. The so-called 5-day BOD measures the amount of oxygen consumed by biochemical oxidation of waste contaminants in a 5-day period.
To determine five-day biochemical oxygen demand (BOD 5), several dilutions of a sample are analyzed for dissolved oxygen before and after a five-day incubation period at 20 °C in the dark. In some cases, bacteria are used to provide a standardized community to uptake oxygen while consuming the organic matter in the sample; these bacteria are ...
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 ...
Secondary treatment (mostly biological wastewater treatment) is the removal of biodegradable organic matter (in solution or suspension) from sewage or similar kinds of wastewater. [ 1 ]: 11 The aim is to achieve a certain degree of effluent quality in a sewage treatment plant suitable for the intended disposal or reuse option.
BOD bottle. BOD test bottles at the laboratory of a wastewater treatment plant. BOD Bottle or an incubation bottle is a main apparatus used for the Biological Oxygen Demand (BOD) test. During the five-day BOD or BOD5 test process, the BOD bottle is used for incubating diluted samples under the 20 °C or 68 °F of temperature.
A rotating biological contactor or RBC is a biological fixed-film treatment process used in the secondary treatment of wastewater following primary treatment. [1][2][3][4][5] The primary treatment process involves removal of grit, sand and coarse suspended material through a screening process, followed by settling of suspended solids.