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. Cod is the amount of oxygen required to chemically breakdown the pollutants whereas bod is the amount of oxygen required to do this. The typical range of bod 5 in domestic wastewater ranges from 100 to 300 mgl. What is the difference in bod, bod5, cbod and nbod, i am so. This ratio varies a lot for domestic sewage as well for septic sewage and may decrease alarmingly with time for. Correlation between bod, cod and toc industrial pollution. Quality of a given water sample depends on some variable factors. Optimizen for municipal wastewater treatment plants. Cod is a chemical test, defined as a chemical oxidation of the sample material. The main objective of the analysis was to investigate the relation between biochemical oxygen demand bod and chemical oxygen demand cod. In this case, the demand for oxygen will be high due to all the bacteria so the bod level will be. Results during the period of the study, the mean influent level of biochemical oxygen demand bod for both the highefficiency system and the lowcost system was.
Total solids, as defined by standard methods and epa, is the material. Codbod ratio is generally high for industrial waste than domestic etc waste. The amount of oxygen required by microorganisms to stabilize decomposable organic matter present in a certain volume of a sample of water, is called biochemical oxygen demand bod. Abbreviations bod biochemical oxygen demand bst bacteria source tracking.
Because of its unique chemical properties, the dichromate ion cr2o7. The crvicod method measures close to the maximum possible oxygen demand of a sample, but generally at least 50% of the demand is from organic. Both cod and bod test methods aim to give an indication of the amount of pollution in a water sample. Real time bod estimations by automated cod analysis. 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. Example of a bod determination a much better nickname the. This requires cod versus bod testing over a specified period of time. Measurement of organic matter concentration organic matter in wastewater is heterogeneous suspended colloidal and dissolved organic matter. Cod or chemical oxygen demand is the total measurement of all chemicals in the water that can be oxidized. Chemical oxygen demand cod and biological oxygen demand bod are the two main characteristic properties that indicate the strength of sewage. The main difference between bod and cod is that bod is the amount of oxygen which is consumed by bacteria while decomposing organic. Differentiate between bod and cod chemistry environmental. Almost all treatment plants are required to measure one of these three items as a measure of the pollution value in the water. Chemical oxygen demand cod vs biological oxygen demand bod.
The basic features of cod, bod and their basic differences are explained in this article. No reasonably constant relationship exists between cod and bod values for either untreated. The key difference between respiration and photosynthesis is that respiration is a biochemical process that utilizes oxygen and converts food into energy while photosynthesis is a process that produces carbohydrates and releases oxygen into the atmosphere respiration and photosynthesis are two of the most important processes of life. The relationship of bod and cod of river water for three rivers in malaysia are investigated over a period of one year. A mathematical correlation is established between the influent and treated effluent parameters, specifically in relation to the bod parameter indicated the prior basis and the assessment criteria of the effluent product. It does not distinguish between biodegradable and nonbiodegradable organic matter. Standardization of bod 5 cod ratio as a biological stability. Bod biochemical oxygen demand is supposed to measure the amount of food or organic carbons that bacteria can oxidize.
Percentage removal of bod, cod, tss and ammonicaln explains the satisfying overall efficiency of the plant. A study on the relationship between bod5 and cod in coastal. Reddy thapar university patiala punjab 147 004 india 2. What is the difference in bod, bod5, cbod and nbod, i am. The mission of the department of ecology is to protect, preserve, and enhance washington s environment. If there is a large quantity of organic waste in the water supply, there will also be a lot of bacteria present working to decompose this waste. Bod, chemical oxygen demand cod, total organic carbon. 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.
Cod is usually measured and the test is simple and easy to perform with the right equipment and can be done in 2. Cod or chemical oxygen demand is the total measurement of all chemicals in the water. What are the differences between chemical oxygen demand cod and biological oxygen demand bod. Cod or chemical oxygen demand is the total measurement of all chemicals in the water that can be oxidized bod biochemical oxygen demand is supposed to measure the amount of food or organic carbons that bacteria can oxidize. Wastewater cod fractionation in the biological wastewater. Dec 28, 2015 biochemical oxygen demand bod and chemical oxygen demand pdf slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. After 5 days, the dissolved oxygen content had dropped to 2. Total dissolved solids tds are a measure of the combined content of all inorganic and organic substances contained in a liquid in molecular, ionized or microgranular colloidal sol suspended form.
A special chemical is added to kill the autotrophic bacteria so nitrification is inhibited so that only the oxidation of cod occurs. Jun 07, 2017 bod refers to the biochemical oxygen demand and cod is the chemical oxygen demand. Bod 5 cod and bod 5 cod sol are both consistent and significant as stability indices. Both the parameters test the oxygendemanding strength of the wastewaters. Organic matter nonbiodegradable and biodegradable toc, cod, do, bod, bodu and serial bod dr. Carbovis 705 iq ts uvvis sensor for insitu measurement of cod, toc, doc, bod, sac, uvt and tss in the effluent. Chemical oxygen demand measure of oxygen equivalent of the organic matter content of the sample that is susceptible to oxidation by a strong chemical. And from those parameters and total cod, the slowly biodegradable sbcod and nonbiodegradable fractions can be calculated. The bod5 value of 1747 mg l 1, cod a value of 3595 m l 1 and journal of applied biotechnology issn 23270640 2020 bodcod ratio of 0. What is biological oxygen demand bod its pretty similar to cod. Almost all wastewater treatment plants are required to measure one of. These can be separated into those based on the 5day biochemical oxygen demand bod as the measure of organic strength and those based on the chemical oxygen demand cod. Chemical oxygen demand cod is a measure of all oxygendemanding substances, including those not amenable to biological treatment, and these, too, are reduced through wastewater treatment. Bod or biological oxygen demand is supposed to measure the amount of food or organic carbons that bacteria can oxidize.
The measured cod is usually more than bod if there is non biodegradable impurity present. Real time bod estimations by automated cod analysis using the pc bod cod duo michael essler aqua diagnostic lindsay peddle mansci inc. If you continue browsing the site, you agree to the use of cookies on this website. The organic matterrelated water quality was substantially recovered after joining the effluent st. Parameters like ph, bod, cod, do, conductivity, tds, alkalinity, hardness, calcium, magnesium, chloride, fluoride, sulphate, nitrate and turbidity were observed in. Accessibility options persons with hearing loss can call 711 for washington relay service. The term also refers to a chemical procedure for determining this amount.
The concentrations of bod exceeded the cod concentrations for the sampling sites near the wwtp, indicating that the bod measurements may be influenced by nitrogenous bod in sewage due to the presence of ammonia. The use of mathematical models for the simulation of wastewater treatment processes has gained widespread acceptance as a tool to aid the design of new works daigger and nolasco, 1995 and the optimisation of existing facilities chambers and jones, 1988, barnett et al. Biological oxygen demand is an important water quality parameter because it greatly influences the concentration of do that will be in the water. It is the broad measure of the strength of the organic matter in a waste stream. What are the differences between chemical oxygen demand. The chemical oxygen demand cod test is commonly used to indirectly measure the amount of organic compounds in water. Correlation between biochemical oxygen demand and chemical.
The biochemical oxygen demand results from the respiratory processes of microorganisms and microorganisms are alive. Zno is an extensively used photocatalyst because of its chemical stability, nontoxicity, and low cost. Highlights bod 5 cod on eluate of leaching test to assess the biological stability of waste. The mean bod level for the highefficiency systems effluent was. Example of a bod determination 200 ml of waste water was collected, aerated and seeded with bacteria. Bod is the amount of oxygen consumed by bacteria while decomposing organic matter under aerobic conditions. Chemical characteristics of sewage bod, cod, nutrients in.
Also, it can be categorized in several ways such as. Its the organic carbon fraction of the sample thats sought after, and its the organics that found the correlation basis for biochemical oxygen demand bod and total organic carbon toc. 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. To help us meet that goal, please consider the environment before you print or request a copy. The qvalue curve for bod used in calculating a water quality index2 illustrates the relationship between bod and water qualitythe higher.
Cod is the amount of oxygen required to chemically breakdown the pollutants whereas bod is the amount of oxygen required. Further, as part of the ultimate bod measurement, other associated tests like dissolved oxygen and ammonical, nitrate and nitrite forms of nitrogen are also discussed. What are the differences between chemical oxygen demand cod. The cod test is much quicker than bod test, but it does not distinguish between the biodegradable and non biodegradable organic matter. Understanding some of the differences between the cod and. Difference between bod and cod definition, test method and. Bod measures the amount of oxygen required by the aerobic. Difference between bod and cod compare the difference. Troubleshooting bacteria levels at wastewater treatment plants information and tools to help wastewater system operators and utility managers minimize bacteria in effluent.
Chemical characteristics of sewage bod, cod, nutrients. What are 5 differences between bod biological oxygen demand and cod chemical oxygen dem. Analysis of total suspended solids and dissolved oxygen. D bod is only a measure ment of consumed oxygen by. Users can purchase an ebook on diskette or cd, but the most popular. The biochemical oxygen demand bod test tries to closely model an aerobic wastewater treatment system and the natural. The bod5 value of 1747 mg l 1, cod a value of 3595 m l 1 and journal of applied biotechnology issn 23270640 2020 bod cod ratio of 0. Biochemical oxygen demand bod testing and measurement in.
Jun 18, 20 chemical oxidant is not specific to oxygenconsuming chemicals that are organic or inorganic, both of these sources of oxygen demand are measured in a cod assay. Biochemical oxygen demand bod and carbonaceous bod. 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. 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. Cod should always measure higher than toc and then bod. Oct 14, 2011 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. Standardization of bod 5 cod ratio as a biological. Bod refers to the dissolved oxygen used by microorganisms in the biochemical oxidation of organic matter whereas cod refers to the oxygen equivalent of the organic material using dichromate in acid solution. The primary difference between bodn determination and other measurements such as ph, conductivity, oxygen, cod, nitrate, etc. For example, the organics in a wastewater sample represented by bod will also be. Biological oxygen demand bod is a measure of the oxygen used by microorganisms to decompose this waste. Whereas, chemical oxygen demand cod is the amount of oxygen required to oxidize and stabilize. The quantity of oxidant consumed is expressed in terms of its oxygen equivalence.
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. Real time bod estimations by automated cod analysis using the. Chemical oxygen demand cod vs biological oxygen demand. Wastewater treatment modeling acknowledgments glossary bibliography biographical sketches. After dilution, the resulting difference between the initial and final do reading simply has.
The asal models jones, 1978, chambers and jones, 1988 are based on bod whilst the iawq1 henze et al. Pdf can be found in find, read and cite all the research you need on researchgate. Technologybased effluent limits when developing effluent limits for a npdes permit, a permit writer must consider limits based on both the technology available to treat the pollutants i. Carbovis 701 iq uvvis sensor for insitu measurement of cod, toc, doc, bod, sac and uvt in the influent, aeration and effluent of municipal wastewater treatment plants. The cod test is not a direct substitute for the bod test.
Correlation between bod, cod and toc 191 exponential equation is fitted for the observed behaviour of bod as a function of cod. Irrespective of the sewer pipes and the types of the areas, it will be changes. For regulatory and treatment purposes, total solids ts can first be classified as suspended or dissolved. If all are the biodegradable organic matter, then cod remains the same as that of bod. The test does not measure the oxygen demand caused. Biochemical oxygen demand measures the quantity of oxygen consumed by microorganisms during the decomposition of organic matter. A study on the relationship between bod5 and cod in. Cod is the amount of oxygen required for the oxidation of total organic matter in water. Biochemical oxygen demand and chemical oxygen demand.
Difference between bod and cod definition, test method. Dec 16, 2015 deals with the measurement of organic matter concentration in water and wastewater. Carbovis 705 iq ts uvvis sensor for insitu measurement of cod, toc, doc, bod, sac, uvt and tss in the. Bod, bod kinetics and cod tests are discussed at length. To distinguish between nitrate and nitrite these sensors with a higher resolution are required.
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. Troubleshooting bacteria levels at wastewater treatment. The temporal variations in bod and cod for urban areas whereas they were relatively irregular for nonurban areas. Bod can, under the uwwtd, be replaced by toc or tod if a relationship can be established. Relationship between ts, tss and tds water chemistry. Whereas, chemical oxygen demand cod is the amount of oxygen required to oxidize and stabilize the organic and inorganic matter present in a certain volume of. These three solids tests can be related with equation. What is the difference in bod, bod5, c bod and n bod, i am so.