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