Biological oxygen demand bod is a measure of the oxygen used by microorganisms to decompose this waste. Also, it can be categorized in several ways such as biological, physical and. Biochemical oxygen demand bod waste water engineering. Biological oxygen demand measures the amount of oxygen used by microorganisms in the oxidation of organic matter. Difference between bod and cod definition, test method. Biochemical oxygen demand bod and chemical oxygen demand pdf 1. Course on industrial biotechnology by professor debabrata. So, that way we can have very particular values of bod and cod depending on the. Codbod ratio is generally high for industrial waste than domestic etc waste. This ratio varies a lot for domestic sewage as well for septic sewage and may decrease alarmingly with time for. Have covered the theory of biochemical oxygen demand including the carbonaceous and nitrogenous demand, dilution method to. It is the rate at which organisms use the oxygen in wastewater while digesting organic matter. Treatment performance of the first fullscale uasb plants treating municipal sewage. Biochemical oxygen demand bod, chemical oxygen demand cod, and by determination of total organic carbon toc.
Carbon toc, theoretical oxygen demand thod, nutrients. Understanding dilution and seeding procedures in bod test. Difference between bod and cod compare the difference. Determination of biological oxygen demand bod in waste. The chemical oxygen demand cod test is commonly used to indirectly measure the amount of organic compounds in water. Hence, the cod bod ratio for the sewage is around 1. Cod is chemical oxygen demand, measured by strong oxidation with dichromate, which oxidizes all organic compounds. Most applications of cod determine the amount of organic pollutants found in surface water e. Toc test will not be conducted but the procedures will be demonstrated to the students. Correlation between bod, cod and toc 191 exponential equation is fitted for the observed behaviour of bod as a function of cod. After fermentation remains waste from bottom of distillation columns, termed stillage. Chemical oxygen demand cod vs biological oxygen demand.
Pdf determination of bod, cod, do and other physico. The fm can be varied by varying mlvss concentration in the aeration tank. These test procedures and relevance of these tests are discussed below. It is a variation of the bod test that measures the oxygen demand due to carbon based. In this case, the demand for oxygen will be high due to all the bacteria so the bod level will be. The bod test measures the oxygen demand due to both carbon and nitrogen based compounds. Chemical oxygen demand cod vs biological oxygen demand bod. 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. What is biological oxygen demand and how does it affect.
The relation between kbase e and k base 10 is kbase 10 kbase e 2. Determine bod5 of wastewater and compute the ultimate bod. Lecture 5 water and wastewater characteristics youtube. Organic matter nonbiodegradable and biodegradable toc, cod, do, bod, bodu and serial bod dr. The qvalue curve for bod used in calculating a water quality index2 illustrates the relationship between bod and water qualitythe higher. Solid retention time srt or mean cell residence time. Cod, nutrients, nitrogen and phosphorus present in waste water different salts and different ions, cations and anions. 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 biological oxygen demand.
Chemical oxygen demand cod is the amount of oxygen consumed by the organic compounds and inorganic matter which were oxidized in waste. Here in such cases you know you can see this bod, cbod, nbod that we have explained. 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. Bod refers to the biochemical oxygen demand and cod is the chemical oxygen demand. Measurement of organic matter concentration organic matter in wastewater is heterogeneous suspended colloidal and dissolved organic matter. Fundamentals of environmental pollution and control prof.
In whole world, cane molasses base distilleries are included under one of the polluting industries in concern to water pollution. Reddy thapar university patiala punjab 147 004 india 2. 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. Ultimate bod ubod the ultimate biochemical oxygen demand ubod is a parameter that quantifies the. Correlation between bod, cod and toc industrial pollution. Unesco eolss sample chapters environmental and ecological chemistry vol. Bodcod bod is biodegradable organics during 5 days at 20 degr. Mihelcic encyclopedia of life support systems eolss 2. The cod what it means theoretical oxygen demand and total. 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. Biological oxygen demand is an important water quality parameter because it greatly influences the concentration of do that will be in the water. The national field manual for the collection of waterquality data nfm is an online report with separately published chapters that provides the protocols and guidelines by which u. Chapter 4 anaerobic sewage treatment using uasb reactors. 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.
Geological survey personnel obtain the data used to assess the quality of the nations surfacewater and groundwater resources. None of the alternatives provide a better assessment of the bioavailability of a waste like the bod test. Cod refers to total cod of the raw wastewater van haandel and lettinga 1994. Enrol today in our site and get access to our study package comprising of video lectures, study material, practice questions and test. Biochemical oxygen demand bod waste water engineering apsed. Bod is a measure of, the amount of oxygen required for the bacteria to degrade the organic components present in water waste water.
The allocation of samples to each batch is given in table 1. National field manual for the collection of waterquality. Biological oxygen demand bod is the amount of oxygen. Biological oxygen demand bod is the rate at which organisms use the.
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