Biochemical oxygen demand bod is an empirical test to provide a measure of the level of degradable organic material in a body of water. Biological oxygen demand journal of chemical education. Biological oxygen demand bod, also known as biochemical oxygen demand, is a bioassay procedure that measures the dissolved oxygen do consumed by bacteria from the decomposition of organic matter. It provides information about the ready biodegradable fraction of the organic load in water.
Biochemical oxygen demand bod is the amount of oxygen, expressed in mgl or parts per million ppm, that bacteria take from water when they oxidize organic matter. Exp 3 biochemical oxygen demand civil engineers pk. The amount of oxygen consumed by these organisms in breaking down the waste is known as the biochemical oxygen demand or bod. Biological oxygen demand bod overview author unknown biochemical oxygen demand bod refers to the amount of oxygen that would be consumed if all the organics in one liter of water were oxidized by bacteria and protozoa revelle and revelle, 1988. Biochemical oxygen demand bod testing and measurement in water. Daoliang li, shuangyin liu, in water quality monitoring and management, 2019. Theoretical oxygen demand, thod nonempirical, but based on chemical reaction, a novel molecular parameter has been proposed for the use in qsar studies. The dissolved oxygen do of the sample is measured initially after mixing the solution and again after five days for the bod 5 or after one day for the bod 1 test. Estimation of biological oxygen demand and chemical oxygen demand for combined sewer systems using synchronous fluorescence spectra. Pdf estimation of biological oxygen demand and chemical. Apr 14, 2018 the chemical oxygen demand cod is an indicative measure of the amount of oxygen that can be consumed by reactions in a measured solution. The interference from nitrogenous demand can be prevented by an inhibitory chemical. Biochemical oxygen demand bod, the amount of dissolved oxygen used by microorganisms in the biological process of metabolizing organic matter in water.
The determination of chemical oxygen demand in waters and. D biochemical oxygen demand bod is the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period. The bod analysis is an attempt to simulate by a laboratory. Measurements that include nitrogenous demand generally are not useful for assessing the oxygen demand associated with organic material. Correlation between biochemical oxygen demand and chemical. Chemical oxygen demand cod is the amount of oxygen consumed by the organic compounds and. The carbohydrates cellulose, starch, sugars, proteins, petroleum hydrocarbons and other materials that comprise organic matter get into water from natural sources and from. Estimation of biological oxygen demand and chemical oxygen demand for combined sewer systems using synchronous fluorescence spectra jin hur 1, bomi lee 1, taehwan lee 1 and daehee park 2 1 department of earth and environmental sciences, sejong university, 98 gunjadong, gwangjingu. Biochemical oxygen demand bod and chemical oxygen demand pdf. Chemical oxygen demand cod analysis science classes. Other sources of oxygen consuming waste include stormwater runoff from farmland or urban streets, feedlots, and failing septic systems. The cod test is often used to monitor water treatment plant efficiency.
Cod is the amount of oxygen required to chemically breakdown the pollutants whereas bod is the amount of oxygen required. Oxygen demand biological and chemical eutrophication. Biochemical oxygen demand or bod is a chemical procedure for determining the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period. Water for cod chemical oxygen demand application water. Bod testing biochemical oxygen demand hill laboratories. Running the biochemical oxygen demand bod test ebs.
Bod atau biochemical oxygen demand adalah suatu karakteristik yang menunjukkan jumlah oksigen terlarut yang diperlukan oleh mikroorganisme biasanya bakteri untuk mengurai atau mendekomposisi bahan organik dalam kondisi aerobik umaly dan cuvin, 1988. The first step in measuring bod is to obtain equal volumes of water from the area to be. Chemical oxygen demand an overview sciencedirect topics. What are the differences between chemical oxygen demand cod and biological oxygen demand bod. The basic features of cod, bod and their basic differences are explained in this article. Dilutions are determined by estimating the amount of biochemical oxygen demand bod in the sample using the measured chemical oxygen demand cod or another suitable surrogate. The biochemical oxygen demand bod is an empirical test used to determine the relative oxygen requirements of the wastewaters, effluents and polluted waters. Chemical oxygen demand cod vs biological oxygen demand. Difference between bod and cod compare the difference. Oxygen demand is a measure of the amount of oxidizable substances in a water sample that can lower do concentrations nemerow, 1974.
Biochemical oxygen demand and chemical oxygen demand. The decay of organic matter in water is measured as biochemical or chemical oxygen demand. Chemical oxygen demand cod is the amount of oxygen necessary to oxidize all of the organic carbon completely to co2 and h2o. The determination of chemical oxygen demand in waters and effluents 2007 methods for the examination of waters and associated materials this booklet contains guidance on methods for the determination of chemical oxygen demand using potassium dichromate solution, and notes for the disposal and recovery of selected reagents. The chemical oxygen demand cod is a measure of water and wastewater quality. Aug 15, 2019 biochemical oxygen demand bod is a chemical procedure for determining the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period. Both cod and bod test methods aim to give an indication of the amount of pollution in a water sample. When you look at water in a lake the one thing you dont see is oxygen. Jun 18, 20 biochemical oxygen demand measures the quantity of oxygen consumed by microorganisms during the decomposition of organic matter.
Determination of the biochemical oxygen demand bod in polluted waste water as a pollution indicator by incubating the bod bottles for five days at 20 degree c the amount of oxygen, taken up by the microorganisms that decompose the organic waste matter in wastewater is known as biological oxygen demand or biochemical oxygen demand. Chemical oxygen demand cod and biological oxygen demand bod are the two main characteristic properties that indicate the strength of sewage. Biochemical oxygen demand bod is the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period. Bod measures the amount of oxygen required or consumed for.
The two main methods used to measure the oxy gen demand of water and wastewater are biochemical oxygen demand bod and chemical oxygen demand. Because of its unique chemical properties, the dichromate ion cr2o7. Dec 28, 2015 dissolved oxygen demand do and chemical oxygen demand cod pdf 1. Corrosionpedia what is a biochemical oxygen demand bod. What are the differences between chemical oxygen demand cod. Biochemical oxygen demand measures the quantity of oxygen consumed by microorganisms during the decomposition of organic matter. Chemical oxygen demand cod vs biological oxygen demand bod. The bod value is most commonly expressed in milligrams of oxygen consumed per litre of sample during 5 days. This is important, because a high bod number means potential septic system problems for homeowners, while a low bod. Chemical oxygen demand cod is defined as the quantityof a specified oxidant that reacts with a sample under controlled conditions. Simultaneous determination of chemical oxygen demand cod. Biochemical oxygen demand bod5 and chemical oxygen demand cod are the most commonly used parameters for the characterization of wastewaters.
Biochemical oxygen demand bod refers to the amount of oxygen that would be consumed if all the organics in one liter of water were oxidized by bacteria and. Nearinfrared spectrometry, wastewater, biological oxygen demand, chemical oxygen demand. Dissolved oxygen demand do and chemical oxygen demand. Cod is the amount of oxygen required to chemically breakdown the pollutants whereas bod is the amount of oxygen required to do this biologically. Simultaneous determination of chemical oxygen demand. Biochemical oxygen demand measures the amount of oxygen consumed in the water by chemical and biological processes. It gains oxygen from the atmosphere and from plants as a result of photosynthesis. Biochemical oxygen demand in water bodies fresh water water. The term also refers to a chemical procedure for determining this amount. Typical sources of bod are readily biodegradable organic carbon carbonaceous, cbod and ammonia nitrogenous, nbod. Allow the brown precipitate to settle out to the bottom.
Bod refers to the amount of oxygen microorganisms must consume in order to oxidize that is, break down all the organic compounds in a liter of wastewater. Mihelcic encyclopedia of life support systems eolss summary biochemical oxygen demand bod is a measure of the dissolved oxygen consumed by microorganisms during the oxidation of reduced substances in waters and wastes. This test is based on the fact that a strong oxidizing agent, under acidic conditions, can fully oxidize almost any organic compound to carbon dioxide. Biochemical oxygen demand bod is a chemical procedure for determining the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period. Estimation of biological oxygen demand and chemical. Oxygen demand is a measure of the amount of oxidizable substances in a water sample that can lower do concentrations. The biochemical oxygen demand results from the respiratory processes of microorganisms and microorganisms are alive. Env20 introduction to environmental engineering adnieva. Both the parameters test the oxygen demanding strength of the wastewaters.
Qsar studies on biological oxygen demand of alcohols. Biochemical oxygen demand bod testing and measurement in. Database the biological oxygen demand bod values collected from literature1 are results of five days incubation of the organic matters at 20c and are given in table i. A discussion of bod and how to monitor it is included at the end of this section. Both the parameters test the oxygendemanding strength of the wastewaters. Biological oxygen demand bod generally represents how much oxygen is needed to break down organic matter in water. It is commonly expressed in mass of oxygen consumed over.
The test for biochemical oxygen demand bod is a bioassay procedure that measures the oxygen consumed by bacteria. Determination of biochemical oxygen demand of area waters. The key difference between bod and cod is that the bod is the oxygen demand of microorganisms to oxidize organic matter in the water under aerobic conditions while the cod is the oxygen demand to oxidize all the pollutants in the water chemically quality of a given water sample depends on some variable factors. The method has been applied to simultaneous determination of chemical oxygen demand and biological oxygen demand in wastewater with satisfactory results. Biochemical oxygen demand biological oxygen demand is an important water quality parameter because it provides an index to assess the effect discharged wastewater will have on the receiving environment. Biochemical oxygen demand bod represents the amount of oxygen consumed by bacteria and other microorganisms while they decompose organic matter under aerobic oxygen is present conditions at a specified temperature. It can, however, pose an indirect threat to living organisms by reducing the level of dissolved oxygen. Ditegaskan lagi oleh boyd 1990, bahwa bahan organik yang terdekomposisi dalam bod adalah bahan organik yang siap. Summary biochemical oxygen demand bod is a measure of the dissolved oxygen consumed by microorganisms during the oxidation of reduced substances in waters and wastes. Estimation of biological oxygen demand and chemical oxygen. What are the differences between chemical oxygen demand. This is the sum of carbonaceous and nitrogenous demand.
Biological oxygen demand bod5 is the amount of oxygen. There are three widelyused methods of measuring oxygen demand. Respiration by aquatic animals, decomposition, and various chemical reactions consume oxygen. Dissolved oxygen demand do and chemical oxygen demand cod pdf. Study of chemical oxygen demand cod in relation to biochemical oxygen demand bod in tigris river at missan governorate. Running water, because of its churning, dissolves more oxygen than still water, such as that in a reservoir behind a dam. Dissolved oxygen concentrations indicate how well aerated the water is, and vary according to a number of factors, including season, time of day, temperature, and salinity. However, it is very difficult to obtain continuous water quality data because of the scarcity of accessible space within the sewer systems and the necessity of separate laboratory. Determination of biological oxygen demand bod in waste.
Biochemical oxygen demand bod is the amount of dissolved oxygen needed i. Biochemical oxygen demand bod dan chemical oxygen demand. The quantity of oxidant consumed is expressed in terms of its oxygen equivalence. Dissolved oxygen refers to the level of free, noncompound oxygen present in water or other liquids. Also, it can be categorized in several ways such as biological. Chemical oxygen demand cod is the amount of oxygen consumed by the organic compounds and inorganic matter which were oxidized in water. Dissolved oxygen demand do and chemical oxygen demand cod pdf 1. Both of these parameters have advantages and disadvantages, and the choice usually depends on many factors such as the time period required todetermine each one of them. Pdf study of chemical oxygen demand cod in relation to. Yang, simultaneous determination of chemical oxygen demand cod and biological oxygen demand bod5 in wastewater by nearinfrared spectrometry, journal of water resource and protection, vol. Biochemical oxygen demand bod and chemical oxygen demand cod, indirect indicators of organic matters, are representative parameters for sewer water quality. Aug 27, 2018 the interference from nitrogenous demand can be prevented by an inhibitory chemical. The higher the bod value, the greater the amount of organic matter or food available for oxygen consuming bacteria.
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 rajasekharan, 2015. Pdf methods for assessing biochemical oxygen demand bod. Biochemical oxygen demand, or bod, is a chemical procedure for determining the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period. Bod and chemical oxygen demand cod, indirect indicators of organic matters, are representative parameters. Bod is a measure of the molecular oxygen utilized during a specific incubation period five or twenty five days to. Biological oxygen demand bod5 amount of dissolved oxygen usedup by microorganism to break up organic materials in water at 20oc over a period of 5 days standard unit of measurement. Because oxygen demand is not a pollutant, it poses no direct threat to fish or other life. Bod is defined as biochemical oxygen demand because the decline in oxygen is from a combination of chemical and biological processes. Mar 24, 2010 biochemical oxygen demand bod and chemical oxygen demand cod, indirect indicators of organic matters, are representative parameters for sewer water quality. A bod test is often used in conjunction with a chemical oxygen demand cod test to provide an indication of the oxygen demand, usually in a waste stream, effluent or surface water such as a river. The biochemical oxygen demand bod is one of the most widely used criteria for water quality assessment. Biological oxygen demand what is biological oxygen demand bod. Biochemical oxygen demand bod in wastewater i real tech. A brownish cloud will appear in the solution as an indicator of the presence of oxygen.
604 463 1429 715 415 447 267 1604 419 341 104 75 1399 811 1402 805 233 541 688 1200 1534 50 860 301 1374 811 1157 283 629 1225 843 1014 686 1251 1283 13 137 824 1370 425 923 124 1177 86 868 765 1193