Measuring biochemical oxygen demand requires taking two measurements. One is measured immediately for dissolved oxygen (initial), and the second is incubated in the lab for 5 days and then tested for the amount of dissolved oxygen remaining (final).
How do you calculate BOD of water?
BOD measurement requires taking two samples at each site. One is tested immediately for dissolved oxygen, and the second is incubated in the dark at 20 C for 5 days and then tested for the amount of dissolved oxygen remaining.
What is BOD and How Is It measured?
The test for biochemical oxygen demand (BOD) is a bioassay procedure that measures the oxygen consumed by bacteria from the decomposition of organic matter (Sawyer and McCarty, 1978). The change in DO concentration is measured over a given period of time in water samples at a specified temperature.
How do you calculate dissolved oxygen?
Dissolved oxygen levels can be measured by a basic chemical analysis method (titration method), an electrochemical analysis method (diaphragm electrode method), and a photochemical analysis method (fluorescence method). The diaphragm electrode method is the most widely used method.
Why BOD is calculated for 5 days?
The BOD is an empirical test to determine the molecular oxygen used during a specified incubation period (usually five days), for the biochemical degradation of organic matter (carbonaceous demand) and the oxygen used to oxidise inorganic matter (e.g., sulphides and ferrous iron).
What is measured by BOD Mcq?
This set of Environmental Engineering Multiple Choice Questions & Answers (MCQs) focuses on “ Oxygen Demand ”. Explanation: BOD is the amount of oxygen required to oxidize only organic matter in sewage.
Why do we measure BOD?
BOD is a measure of the amount of oxygen required to remove waste organic matter from water in the process of decomposition by aerobic bacteria (those bacteria that live only in an environment containing oxygen). BOD is used, often in wastewater-treatment plants, as an index of the degree of organic pollution in water.
What is BOD and COD?
The biochemical oxygen demand (BOD) represents the amount of dissolved oxygen (DO) consumed by biological organisms when they decompose organic matter in water. The chemical oxygen demand (COD) is the amount of oxygen consumed when the water sample is chemically oxidised.
What is Winkler A and B?
The Winkler test is used to determine the concentration of dissolved oxygen in water samples. In the test, an excess of manganese(II) salt, iodide (I−) and hydroxide (OH−) ions are added to a water sample causing a white precipitate of Mn(OH)2 to form.