Determination of chemical oxygen demand cod using an alternative wet chemical method free of mercury and dichromate article pdf available in water research 122 june 2017 with 6,802 reads. The amount of oxygen consumed by these organisms in breaking down the waste is known as the biochemical oxygen demand or. Typically this measurement is used to monitor and control oxygen consuming pollutants, both inorganic and organic, in domestic and industrial wastewaters. 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. Chemical oxygen demand cod reagents reagecons product offering includes reagents for the two accepted methods for measuring cod at concentrations less than 400mgl. There are three widelyused methods of measuring oxygen demand. Biochemical oxygen demand bod refers to the amount of oxygen that would be. Biochemical oxygen demand bod is a procedure used to measure the biodegradable organic material in a given water sample. Chemical oxygen demand titrimetric, high level for saline waters analyte. The quantity of organic matter or the demand of oxygen is calculated by determining how much oxidizing chemical was. However, this analytical method is timeconsuming generally 5 days, bod5.
This is one of the most commonly permitted parameters due to the drastic negative effects bod laden water can have on natural streams. Only chemically digest able matter can be determined by the cod test. Odell inorganic chemistry branch chemistry research division. This component of envirolab shows the analysis of a biochemical oxygen demand bod data set for three different water samples. 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.
A study of dairy effluent of various products on the basis. Many other variations of oxygen demand measurements exist, including using shorter and longer incubation periods and tests to determine rates of oxygen uptake. Where the concentration is greater than 400mgl, dilute the sample. Biochemical oxygen demand environmental protection agency.
Alternatively, the total bod is wellsuited, due to the determination of the nitrogen as. Biochemical oxygen demand bod is a simple and practical indicator of the total organic content that is available to organisms plus any chemicals that spontaneously react with o 2. Biochemical oxygen demand bod and chemical oxygen demand pdf. Standard test methods for chemical oxygen demand dichromate. 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. Biological oxygen demand bod is an important and widely used sum parameter to evaluate water quality. The chemical oxygen demand cod is a measure of water and wastewater quality. Simultaneous determination of chemical oxygen demand. The siphon hose must be made of surgical gum latex rubber, polypropylene or polyethylene to avoid introducing bod into the dilution water. Find out information about biochemical oxygen demand test. Biochemical oxygen demand bod testing and measurement in water. When volumes of sample used exceed 150 ml, additional nutrients should be added to the sample bottle. Carefully fill a bod bottle with sample water without making air bubbles.
Epa on march 31, 2005 for wastewater compliance monitoring. A bod determination is performed by taking a water sample and incubating it over a 5 or 20day period while monitoring the dissolved oxygen concentration every 12 hours. Oxygen demand, biochemicaldilution method 8043 hach. Test method b micro cod by sealed digestion and spectrometry.
Determine cod values of 50 mg o2l by using procedures 5220b. The bod value is most commonly expressed in milligrams of oxygen consumed per litre of sample during 5 days. The biochemical oxygen demand results from the respiratory processes of microorganisms and microorganisms are alive. Add 2 ml of alkaliiodideazide reagent in the same manner. Simultaneous determination of chemical oxygen demand cod. Dissolved oxygen demand do and chemical oxygen demand cod pdf. Abbreviated bod test explanation of biochemical oxygen demand test. Pdf methods for assessing biochemical oxygen demand bod. A novel spectrophotometric assay method using homemade reagents that can be used to determine the chemical oxygen demand cod in real wastewater was described in the study of jun li et al.
Typical sources of bod are readily biodegradable organic carbon carbonaceous, cbod and ammonia nitrogenous, nbod. Dec 28, 2015 dissolved oxygen demand do and chemical oxygen demand cod pdf 1. The biochemical oxygen demand is an empirical test that measures the amount of oxygen used by bacteria as they metabolize organic matter at 20 ocelsius, in the dark, usually over a 5 day period. Bacteria rapidly degrade organic material through the process of aerobic respiration. Chemical oxygen demand cod is used to determine the quantity of pollution in water after wastewater treatment.
To begin the stored program initiate the program mode by making the following key strokes. Running the biochemical oxygen demand bod test ebs. Carbonaceous biochemical oxygen demand cbod, the amount of oxygen needed to break down carbon compounds, excluding nitrogen compounds. A bod determination is performed by taking a water sample and incubating it over a 5 or 20day period while monitoring the. General discussion the biochemical oxygen demand bod determination is an empirical test in which standardized laboratory procedures are used to determine the relative oxygen requirements of wastewaters, ef. Dissolved oxygen depletion due to biological oxygen demand, chemical oxygen demand and metabolic wastes also is a potential problem. The industrial and municipal waste water effluents may contain very high amounts of organic matter and if discharged into natural water bodies, it can cause complete depletion of dissolved oxygen leading to. A study of dairy effluent of various products on the basis of.
Subtleties of the biochemical oxygen demand test ebs. Add 2ml of manganese sulfate to the bod bottle carefully by inserting the pipette just below the surface of water. It can, however, pose an indirect threat to living organisms by reducing the level of dissolved oxygen. This oxygen transaction is the source of the tests name, chemical oxygen demand. How to determine biochemical oxygen demand in water and wastewater. Dissolved oxygen refers to the level of free, noncompound oxygen present in water or other liquids. Procedure blank preparation and titration using distilled water as sample, prepare and titrate a blank with the same procedure and reagents see below accept the obtained titrant volume as blank volume chemical oxygen demand of water. Water for cod chemical oxygen demand application water. The quantity of oxidant consumed is expressed in terms of its oxygen equivalence. 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. Dissolved oxygen demand do and chemical oxygen demand cod pdf 1. Biochemical oxygen demand test article about biochemical.
Biochemical oxygen demand bod is an empirical test to provide a measure of the level of degradable organic material in a body of water. The bod electrode method is suitable for determining the bod of water and wastewater. Estimation of biochemical oxygen demand based on dissolved. 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. D dissolved oxygen demand and chemical oxygen demand chetan singh pundeer 12 ce 036 chetan singh pundeer 12 ce 036 1 2. The biochemical oxygen demand bod indicates the amount of oxygen which is needed for the biological degradation of organic substances in water since the generally used bod 5 excludes the nitrification part of the process, this parameter is poorly suited for the control of waste water treatment plants. Tygon and black rubber can add oxygen demand to the water. Dissolved oxygen demand do and chemical oxygen demand. In essence a cod test determines the amount of carbon based materials by measuring the amount of oxygen the sample will react with. Biochemical oxygen demand bod testing and measurement in. Biochemical oxygen demand bod is the amount of dissolved oxygen needed i. A standard laboratory procedure for measuring biochemical oxygen demand. The cod test is often used to monitor water treatment plant efficiency.
Samples with higher cod concentrations may be processed by appropriate dilution of the sample. Cod determination takes less time than the biological oxygen. 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. A novel spectrophotometric assay method using homemade reagents that can be used to determine the chemical oxygen demand cod in real wastewater was. The higher value of chemical oxygen demand indicates the higher organic pollution in the water sample. Epa requires wastewater treatment plants to bring bod within limits before discharging treated wastewater, and accurate test results must be recorded for regulatory reporting. 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. 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. Biochemical oxygen demand values are a measure of food for naturally occurring microorganisms. The estimated detection limit for program number 2700 is 0. Chemical oxygen demand thermo orion method codl00 and codh00 revision 5, 03252005 accepted by u.
The wastewater sampling method relates to the sampling of all wastewater treatment plants in. The quantity of organic matter or the demand of oxygen is calculated by determining how much oxidizing chemical was consumed during the test. Biochemical oxygen demand bod, the amount of oxygen needed by organisms to break down organic material present in a water sample. The test for biochemical oxygen demand bod is a bioassay procedure that measures the oxygen consumed by bacteria from the decomposition of. 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. It also allows the use of dilution water having an oxygen demand 0. Method specified is applicable to water with a value between 30 mgl and 700 mgl.
Pdf the biochemical oxygen demand bod is one of the most widely used. Standard operating procedure chemical oxygen demand, cod chemsop 7. Pdf determination of biochemical oxygen demand bod without. The biochemical oxygen demand bod determination is an empirical test in which standardized laboratory procedures are used to determine the relative. Determination of chemical oxygen demand of wastewater. Pdf determination of chemical oxygen demand cod using. Chemical oxygen demand testing is typically performed using a strong oxidizing chemical. Organic matter is oxidized into carbon dioxide and water in an acidic condition. The oxygen required for the degradation of the organic matter biologically is called the biochemical oxygen demand bod. Because of its unique chemical properties, the dichromate ion cr2o7. Interferences and limitations oxidation of most organic compounds is 95 to 100% of the theoretical value. Determination of biological oxygen demand bod in waste. The bod determination is an empirical test in which standardised laboratory procedures are used to determine the relative oxygen requirements of wastewaters, effluents and polluted.
In order to promote public education and public safety, equal justice for all, a better informed citizenry, the rule of law, world trade and world peace, this legal document is hereby made available on a noncommercial basis, as it is the right of all humans to know and speak the laws that govern them. Biochemical oxygen demand bod is a simple and practical indicator of the total organic content that is available to organisms plus any chemicals that spontaneously react with o2. This method involves the incubation of a water sample that is diluted with deionised. Loss of a toxicant through volatilization and adsorption to exposure chambers may occur peltier and weber, 1985. So that you can avoid the formation of air bubbles. Oxygen demand is an environmental chemistry term that may refer to. Because oxygen demand is not a pollutant, it poses no direct threat to fish or other life. A cod test can be used to easily quantify the amount of organics in water. This system eliminates the need for running an incubated fiveday dilution water blank. Bod biological oxygen demand lar process analysers.
Biochemical oxygen demand an overview sciencedirect topics. Test method a macro cod by reflux digestion and titration. The bod analysis is an attempt to simulate by a laboratory test the effect that organic material in a water body will have on the do in that water body. In order to promote public education and public safety, equal justice for all, a better informed citizenry, the rule of law, world trade and world peace, this legal document is hereby made available on a noncommercial basis, as it is the right of all humans to. The term also refers to a chemical procedure for determining this amount.
Bod is a measure for the quantity of oxygen required for the biodegradation of organic matter carbonaceous demand in water but it is affected by oxygen consumed for oxidising inorganic material such as sulphides and ferrous iron and by the amount of oxygen used. The theoretical blank volume can be calculated according to the following formula. If the value exceeds 700 mgl, the water sample is diluted. Biochemical oxygen demand bod is a measure of the dissolved oxygen consumed by microorganisms during the oxidation of reduced substances in waters and wastes. 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. In addition to our indian standard, we also discuss in brief regarding the procedure stated in 1 apha standard methods for the examination of water and wastewater 20. Biological oxygen demand 30 ps2829a modified bod 5 procedure for the classroom materials list item quantity dissolved oxygen sensor 1 temperature sensor or thermometer 1 plastic lab bottle with screw top, 2l 2 plastic lab bottle with screw top, 1l 1 dark plastic or glass lab bod bottle with airtight top, 300ml 3.
Other related analytical values are biochemical oxygen demand bod, total organic carbon toc, and total oxygen demand tod. Pdf determination of chemical oxygen demand cod using an. Biological oxygen demand bod is a measure of the oxygen used by microorganisms to decompose this waste. These compounds are common constituents or metabolic. Due to the 5d test period, however, bod5 is not considered as a suitable parameter for a process control of water treatment processes and for a. Other than that, they are really the identical process. In this case, the demand for oxygen will be high due to all the bacteria so the bod level will be. Biochemical oxygen demand is a definitive indicator of required treatment in wastewater, and estimating bod is an important part of wastewater treatment process control. The carbohydrates cellulose, starch, sugars, proteins, petroleum hydrocarbons and other materials that comprise organic matter get into water from natural sources and from.
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