Bod, cod, and toc may 10, 2020 the organic strength of wastewater is measured in three ways. Typically, municipal wastewater treatment plants will use bod5 as a measure of the organic concentration into, and through, the wastewater plant. A cod test can be used to easily quantify the amount of organics in water. It represents the quantity of oxygen which is consumed in the course of aerobic processes of decomposition of organic materials, caused by microorganisms. Chemical oxygen demand is an important water quality parameter because, similar to bod, it provides an index to assess the effect discharged wastewater will have on the receiving environment.
The typical range of bod 5 in domestic wastewater ranges from 100 to 300 mgl. Biochemical oxygen demand or biological oxygen demand bod is a measure of the amount of dissolved oxygen do required by aerobic microorganisms to decompose organic matter present in a sample of water at a certain temperature over a studied period. What is the relationship between the cod and bod values in waste water. Bod value is usually expressed in milligrams of oxygen per liter of water mgl. Since the introduction of the closedreflux micro method in the early 1980s, cod analysis has become increasingly used at municipal wastewater treatment plants for process monitoring and to aid in process control. Wastewater treatment and discharge 2006 ipcc guidelines for national greenhouse gas inventories 6. Unesco eolss sample chapters environmental and ecological chemistry vol. Tenburr university of engineering and technology, lahore, pakistan and university of birmingham, birmingham, u.
Cod or chemical oxygen demand is the total measurement of all chemicals in the water that can be oxidized. 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. Bod is the biochemical oxygen demand for a period of five days. A consumers guide to bod 5 5day biochemical oxygen. The chemical oxygen demand cod test is commonly used to indirectly measure the amount of organic compounds in water. None of the alternatives provide a better assessment of the bioavailability of a waste like the bod test. How to reduce chemical oxygen demand cod in wastewater. Correlation between biochemical oxygen demand and chemical. It is the broad measure of the strength of the organic matter in a waste stream. The temperature of stream water influences the amount of dissolved oxygen present. It is commonly expressed in mass of oxygen consumed over. Biochemical oxygen demand and chemical oxygen demand.
A full explanation of any of the parameters can be found by clicking on the blue links. Bod is the amount of oxygen consumed by bacteria while decomposing organic matter under aerobic conditions. The higher the bod value, the greater the amount of organic matter or food available for oxygen consuming bacteria. Note that the bod value is close to zero when the cod value is around. Bod n biochemical oxygen demand after n days is defined in detail in german standard din 38 409h51 1 and is associated with certain experimental conditions. Bod is the necessary oxygen demand of the microbes to break down the pollutants of the impure water. The chemical oxygen demand cod analysis, by the dichromate method, is more commonly used to control continuously monitor wastewater treatment systems, the cod of an effluent is usually higher than the bod 5 since the number of compounds that can be chemically oxidized is greater than those that can be degraded biologically, it is also common to. 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. Cod or chemical oxygen demand is the total measurement of all chemicals. Bod, cod, toc and tod sum parameters in environmental. Therefore, the significant different results for the bodcod ratio may be. If you continue browsing the site, you agree to the use of cookies on this website. Cod is chemical oxygen demand, measured by strong oxidation with dichromate, which oxidizes all organic compounds. The makes them significant when is comes to the treatment of water.
A consumers guide to bod 5 5day biochemical oxygen demand used in wastewater testing. The main difference between bod and cod is that bod is the amount of oxygen which is consumed by bacteria while decomposing organic matter under aerobic conditions whereas cod is the amount of oxygen required for the chemical oxidation of total organic matter in water. Bod biochemical oxygen demand is supposed to measure the amount of food or organic carbons that bacteria can oxidize. Also, it can be categorized in several ways such as biological. Innovox analyzer data and the actual cod measurement comparison chart. Mihelcic encyclopedia of life support systems eolss 2. Biochemical oxygen demand bod in wastewater treatment. The standard 5day bod 5 test for biological oxygen demand in wastewater is used to evaluate the effectiveness of wastewater treatment by a public or private sewer or septic system. Significance of cod, bod and toc correlations in kinetic. None of the alternatives provide a better assessment of the bioavailability of a waste like the. Bod refers to the biochemical oxygen demand and cod is the chemical oxygen demand. Pdf wastewater was collected from the sugar and cement industrial area situated in north karnataka.
Chemical oxygen demand cod vs biological oxygen demand. Chapter 3 selection of water quality variables world health. Bod stands for biological oxygen demand and its high value in the water body is significant to the oraganic wastes in the water source. The two most common parameters used to recognize the composition of wastewater are the biochemical oxygen demand. Biochemical oxygen demand bod and chemical oxygen demand pdf 1. Simultaneous determination of chemical oxygen demand. Closely related to biochemical oxygen demand bod, chemical oxygen demand cod is another important water quality parameter that industrial and municipal authorities should be familiar with to determine the best wastewater treatment methods for their needs. The procedure follows the ita study report1 recommendations and is adapted based on our customer feedback and other industry case studies. Chemical oxygen demand cod is the amount of oxygen necessary to oxidize all of the organic carbon completely to co2 and h2o. Bodcod bod is biodegradable organics during 5 days at 20 degr. Activated sludge microbiology problems and their control.
Attached is a page from a masters thesis which shows the relationship of measured values of bod and cod. The cod test only requires 23 hours, while the biochemical or biological oxygen demand bod test requires 5 days. Toc or total organic carbon is the measurement of organic carbons. How to reduce chemical oxygen demand cod in wastewater written by aos treatment solutions on november 1, 2018. Estimation of biological oxygen demand and chemical. What does a high value of bod of a water body imply. Organics 2 university of georgia cooperative extension circular 922. Enter bod or cod values into the correlation tool spreadsheet bod or cod mgl column upon receiving the lab results.
Bod is a measure of, the amount of oxygen that require for the bacteria. Difference between bod and cod definition, test method. Biochemical oxygen demand measures the quantity of oxygen consumed by microorganisms during the decomposition of organic matter. Bod and cod in hindi biochemical oxygen demand and chemical oxygen demand duration. Chemical oxygen demand an overview sciencedirect topics. Bod, cod, toc and tod sum parameters in environmental analysis. Most applications of cod determine the amount of organic pollutants found in surface water e. Chemical oxygen demand cod analysis science classes. Printed m great britain significance of cod, bod and toc correlations in kinetic models of biological oxidation j. Biochemical oxygen demand bod and chemical oxygen demand cod both measure the quantity of organic compounds found in water. Cod correlation provides operations, laboratory benefits. A seasonal assessment of groundwater pollution due to. Ultimate bod ubod the ultimate biochemical oxygen demand ubod is a parameter that quantifies the. High bodcod is indirect indicator of the organic content ammonia is inorganic and creates an oxygen demand as it is converted to nitrate.
The relationship of bod and cod of river water for three rivers in malaysia are investigated over a period of one year. The importance of biochemical oxygen demand bod in the. Thanks for the a2a anupal baruah the answer to this question is among the basic building blocks of environmental engineering, yet many experts working on wastewater management and stream supervision, stumble down when they face this question. Biochemical oxygen demand bod in wastewater i real tech. Correlation between bod, cod and toc 191 exponential equation is fitted for the observed behaviour of bod as a function of cod. Chemical oxygen demand cod is a measure of all oxygendemanding substances, including those not amenable to biological treatment, and.
Chemical oxygen demand cod vs biological oxygen demand bod. In practice, in order to arrive at significant miles tones which will. A whole variety of organic matter can be present in water, which cannot be defined individually with considerable analytical effort and in short time. 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 represents the quantity of oxygen which is consumed in the course of aerobic processes of decomposition of organic materials, caused by.
The organic strength of wastewater is measured in three ways. 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. Chemical oxygen demand cod in wastewater i real tech water. Bod primer page 4 of 61 biological background of all bodn determinations the primary difference between bodn determination and other measurements such as ph, conductivity, oxygen, cod, nitrate, etc. Biochemical oxygen demand bod and chemical oxygen demand pdf slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Higher cod levels mean a greater amount of oxidizable organic material in the sample, which will reduce dissolved oxygen do levels.
What is the relationship between the cod and bod values in. Particularly in enugunorth senatorial district, no single study have made bod and cod seasonal routine determinations over a. Biochemical oxygen demand bod and chemical oxygen demand pdf. Chemical oxygen demand or cod is a measurement of the oxygen required to oxidize soluble and particulate organic matter in water. Cod is the amount of oxygen required for the oxidation of total organic matter in water. Received 26 july 1979 altraetthe results of pilot scale studies on the activatedsludge. Significance of the bod test most commonly required test on wpdes and npdes discharge permits. The importance of biochemical oxygen demand bod aqualytic.
It measures all organic contaminants, including those that are not biodegradable. 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. Difference between bod and cod compare the difference. It is equal to the amount of dissolved oxygen required by organisms for aerobic decomposition of organic matter present in the water. There is a relationship between bod and cod for each specific sample, but it must be established empirically. The term also refers to a chemical procedure for determining this amount. Biochemical oxygen demand bod is the amount of dissolved oxygen needed i. Cod is closely related to bod or biochemical oxygen demand, the difference being that bod is a test of the level of organic matter that can be biologically oxidised while cod is a test of the amount of organic matter that can be chemically oxidised. Aerobic biotransformation dissolved oxygen is consumed in the process of convert organic matter into inorganic matter. As the name implies, a do test measures the concentration of oxy gen dissolved in a water or wastewater sample. One definition of a wastewater treatment plant operator is a bug farmer, one who controls the aeration basin environment to favor good microbiology.
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