Biochemistry Biochemical Oxygen Demand, BOD, as it is commonly abbreviated, is one of the most important and useful parameters measured characteristics indicating the organic strength of a wastewater. BOD measurement permits an estimate of the waste strength in terms of the amount of dissolved oxygen required to break down the wastewater. The specifics of the analysis are discussed in detail in Standard Methods for the Examination of Water and Wastewater.
Ammonia oxidation is inhibited. The sample is kept in a sealed container fitted with a pressure sensor.
A substance that absorbs carbon dioxide typically lithium hydroxide is added in the container above the sample level. The sample is stored in conditions identical to the dilution method.
Oxygen is consumed and, as ammonia oxidation is inhibited, carbon dioxide is released. The total amount of gas, and thus the pressure, decreases because carbon dioxide is absorbed. From the drop of pressure, the sensor electronics computes and displays the consumed quantity of oxygen.
The main advantages of this method compared to the dilution method are: Biosensor[ edit ] An alternative to measure BOD is the development of biosensors, which are devices for the detection of an analyte that combines a biological component with a physicochemical detector component.
Enzymes are the most widely used biological sensing elements in the fabrication of biosensors. Their application in biosensor construction is limited by the tedious, time consuming and costly enzyme purification methods.
Microorganisms provide an ideal alternative to these bottlenecks. Moreover, the use of microbes in biosensor field has opened up new possibilities and advantages such as ease of handling, preparation and low cost of device.
A number of pure cultures, e. Trichosporon cutaneum, Bacillus cereus, Klebsiella oxytoca, Pseudomonas sp. On the other hand, many workers have immobilized activated sludge, or a mixture of two or three bacterial species and on various membranes for the construction of BOD biosensor.
The most commonly used membranes were polyvinyl alcohol, porous hydrophilic membranes etc. Such a formulated consortium can be immobilized on suitable membrane, i.
Suitability of charges nylon membrane lies in the specific binding between negatively charged bacterial cell and positively charged nylon membrane. So the advantages of the nylon membrane over the other membranes are: The dual binding, i.
Adsorption as well as entrapment, thus resulting in a more stable immobilized membrane. Such specific Microbial consortium based BOD analytical devices, may find great application in monitoring of the degree of pollutional strength, in a wide variety of Industrial waste water within a very short time.Biological Oxygen Demand (BOD) is a measure of the rate at which oxygen is being removed from sample of water.
This is the standard test used at Sewerage Treatment Plants.
This is the standard test used at Sewerage Treatment Plants. Finding the biological oxygen demand of a sample(BOD) Two determinations of the dissolved oxygen content of a mL sample of water made five days apart, gave ppm and ppm of dissolved O2, respectively. What is the biological oxygen demand of the sample?
Finding the biological oxygen demand of a sample(BOD) Related . Biological oxygen demand (BOD) is defined as the quantity of dissolved oxygen that is required by the micro-organisms for the biodegradation of organic matter present in a water body.
Biological Oxygen Demand (BOD) is a measure of the rate at which oxygen is being removed from sample of water. This is the standard test used at .
Dissolved Oxygen in Water Essay example; Dissolved Oxygen in Water Essay example. Words Jul 10th, 3 Pages. Decreased DO levels may also be indicative of too many bacteria and an excess amount of biological oxygen demand Comparative analysis of portable water of Dhaka City Course: ENV Section: 34 Semester: .
Because most samples of wastewater will have a BOD higher that the amount of oxygen available in the BOD bottle during the incubation period, the samples must be diluted. This dilution is done by adding dilution water to the sample in the BOD bottle.