Hach bod instruments combined with hach bod reagent for biochemical oxygen demand testing help wastewater treatment plants achieve optimum bod measurement while allowing. The higher value of chemical oxygen demand indicates the higher organic pollution in the water sample. The test has its widest application in measuring waste loadings to treatment plants and in evaluating the bodremoval. Methods for assessing biochemical oxygen demand bod. To understand the need for seeding in the bod test c. Understanding the need and procedure for dilution and seeding in bod measurement key concepts.
Difference between bod and cod compare the difference. Summary of contract required detection limits, holding times. Limitations test period is too long not good for process control test is imprecise and unpredictable the test is simply not very easya lot of qc makes it timeconsuming can take years of experience to master it cannot evaluate accuracy no universally accepted standard other than gga accuracy at 200 ppm vs. A glance to the united states shows that the standard methods include the dilution method as the 5210 b 5day bod test and the respirometric. However, this analytical method is timeconsuming generally 5 days, bod5, and the. Biochemical oxygen demand bod is usually expressed in mgl but can also be expressed in lbsday. If chlorine is present in the sample, a dechlorination chemical e. Appropriate protective equipment should be worn when undertaking the bod biochemical oxygen demand electrode method. Determination of biochemical oxygen demand bod omnilab. Obviously, the bod test is not the most scientifically based test we perform. To determine the biochemical oxygen demand bod of various samples of water b. National field manual for the collection of waterquality. The test for biochemical oxygen demand bod is a bioassay procedure that measures the oxygen consumed by bacteria from the decomposition of.
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. Bod test bottles at the laboratory of a wastewater treatment plant. Since less dissolved oxygen is available in the water, fish and other aquatic organisms may not survive. The bod5 method measures most of the carbonaceous stage of the bod typically about 60% to. The biochemical oxygen demand bod test is a measurement of the quantity of oxygen required by bacteria to biologically oxidize organic material under aerobic conditions. It is a variation of the bod test that measures the oxygen demand due to carbon based. Determination of biological oxygen demand bod in waste. Summary of contract required detection limits, holding times, and preservation for biochemical oxygen demand bod analytical parameter contract required detection limit crdl. On the determination of the kinetic parameters for the bod test.
What you should know the actual procedure is so much more involved than the summary given above. A consumers guide to bod 5 5day biochemical oxygen demand. The bod test measures the molecular oxygen used during a specified incubation. Bod is a timeconsuming test while cod can finish within a few hours. Cod often is used as a measurement of pollutants in wastewater and natural waters. Its widest application is in measuring waste loadings to treatment plants and in evaluating a plants efficiency in removing bod. On the determination of the kinetic parameters for the bod. The test for biochemical oxygen demand bod is a bioassay procedure that measures the oxygen consumed by bacteria from the decomposition of organic matter sawyer and mccarty, 1978. The samples were collected and the bod test carried out according to standard methods 1980.
Understanding the need and procedure for dilution and. Aug 27, 2018 biochemical oxygen demand bod testing determines the relative oxygen requirements of wastewaters, effluents, and polluted waters. As an alternative, use the method bod calculationgraphical method on page 6 to calculate the test results. Two additional longterm bod procedure documents may be consulted for reference and comparison. Biochemical oxygen demand environmental protection agency. What is the difference in bod, bod5, cbod and nbod, i am. Composed of two metal electrodes in contact with supporting electrolyte and separated from the test solution by a gas permeable. Scope and application this method determines the bod of a water sample. Protocolprocedure and test specifications, environmental protection division, atlanta, georgia, november 1989, 31 pp. So that you can avoid the formation of air bubbles. Pdf the biochemical oxygen demand bod is one of the most widely used. There can be confusion about bod and its relationship with dissolved oxygen do readings. Pdf methods for assessing biochemical oxygen demand bod. The bod test measures the oxygen demand due to both carbon and nitrogen based compounds.
Oxygen demand, biochemicaldilution method 8043 hach. A consumers guide to bod 5 5day biochemical oxygen. The bod test reflects the amount of dissolved oxygen do consumed by bacteria while oxidizing these materials. Biochemical oxygen demand bod testing and measurement in. Biochemical oxygen demand bod testing and measurement in water.
Dissolved oxygen is essential for the life of aquatic fauna and flora, and the bod test is a measure of the ecological impact that effluent water may have on the receiving body of water river, lake, etc. 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. Cod is the amount of oxygen required for the oxidation of total organic matter in water. It is the rate at which organisms use the oxygen in wastewater while digesting organic matter. Difference between bod and cod definition, test method and. 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. It describes the procedure for undiluted samples whose bod must, however, lie at a low level of between 0. Standard methods online standard methods for the examination of water and wastewater.
For the airsaturated water calibration procedure, you either vigorously shake the solution or bubble air through it. Bod is the amount of oxygen consumed by bacteria while decomposing organic matter under aerobic conditions. Even though the end result of bod testing is a final bod reading, the calculations are all based on do readings. Since bod is a biochemical process, it is not a precise quantitative test. Measuring bod is required as part of the environmental discharge permit and is an important parameter to evaluate the effectiveness of the wastewater treatment operation. The holding time for a bod sample is 48 hours from collection. Georgia epd longterm bod test specifications revised january. Conduct a chlorine residual analysis on a portion of the sample collected. The format has merely been streamlined and made more reliable to improve accuracy and save time. The bod analyses were made on foodprocessing effluents bakeries and fishprocessing plants with bod 5 ranging from 629 mg1 to 938 mg1. The biggest challenge in the bod test is that of time. There are, however, some concepts you should be familiar with to obtain the best quality results. Biochemical oxygen demand encyclopedia of life support.
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. The most popular current testing method for cod involves using sealed and heated i. 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. Accurate bod measurements with electrochemical and. The determination of chemical oxygen demand in waters and effluents 2007 methods for the examination of waters and associated materials this booklet contains guidance on methods for the determination of chemical oxygen demand using potassium dichromate solution, and notes for the disposal and recovery of selected reagents. Potassium iodidestarch paper can be used as a quick qualitative test for residual chlorine. The term also refers to a chemical procedure for determining this amount. If no residual is found, proceed with the bod analysis utilizing seeded dilution water.
Difference between bod and cod definition, test method. Biochemical oxygen demand bod 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. Carefully fill a bod bottle with sample water without making air bubbles. The respirometric method can be compared to the dilution method, and standard methods are discussed in contrast to selfmonitoring methods. Understanding dilution and seeding procedures in bod test target group. Mar 17, 2015 biochemical oxygen demand bod bod is an empiric laboratory assay which measures the amount of organic matter contained in a water sample. The test result should be considered as an independent measurement of organic matter in the sample, rather than as a substitute for the bod or toc test. Understanding dilution and seeding procedures in bod test. Pdf determination of biochemical oxygen demand bod without. The test usually runs for a fiveday period, but can run 7 or 10 days as well, depending on specific sample circumstances. The change in do concentration is measured over a given period of time in water samples at a specified temperature.
The bod electrode method is suitable for determining the bod of water and wastewater. The method consists of filling with diluted and seeded sample, to overflowing. The determination of chemical oxygen demand in waters and. Biochemical oxygen demand bod standard method 5210 b 5day bod test table 1. They include standard methods 20th edition, and the longterm bod procedure used by. The bod determination is an empirical test in which.
Biochemical oxygen demand bod is also sometimes referred to as biological oxygen demand, but the latter term is considered inappropriate by many scientists and. 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. Chemical oxygen demand cod is used to determine the quantity of pollution in water after wastewater treatment. Sewage was dumped in a river and it took five days for it to reach the ocean, hence the fiveday incubation requirement in the bod method. If a residual is found, proceed with the following steps before initiating the bod test. Bod is determined by incubating a sealed water under specific temperature sample for five days and measuring the loss of oxygen from. The graphical calculation method is also a tool for. An extended ubod ultimate bod test that measures oxygen consumption after 60 days or more is sometimes required in wastewater permits. Dissolved oxygen is measured initially and after incubation, and the bod is computed from the difference between initial and final do.
Protocol procedure and test specifications, environmental protection division, atlanta, georgia, november 1989, 31 pp. The bod level is determined by comparing the do level of a water sample taken immediately with the do level of a water sample that has been incubated in a dark location for 5 days. Biochemical oxygen demand bod is the amount of dissolved oxygen needed i. Syringefilter procedure for processing samples for analysis of organic compounds by dai lcmsms this section of chapter 5 of the national field manual for the collection of waterquality data nfm describes the field procedures for collecting smallvolume samples using a syringetip filtration method. Only chemically digest able matter can be determined by the cod test. 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. Therefore, do readings must be as accurate as possible to ultimately get accurate bod results. Bod primer page 2 of 61 preface the determination of biochemical oxygen demand is always a topic of discussion with regard to the method and its applicability.
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. The bod determination is an empirical test in which standardised laboratory procedures are. The determination of biochemical oxygen demand is always a topic of discussion with. How to measure biochemical oxygen demand the hydrology project.
Determination of chemical oxygen demand of wastewater. Procedure lab test for cod and bod bod test procedure 1. No dilution is required for samples whose 5day bod is less than 6 mgl. Summary of contract required detection limits, holding. In the manual, therefore, the bis procedure for measurement of bod is 3205 part 44. Pdf biochemical oxygen demand bod is a generalized parameter in the. To check the procedure by determining the bod value of a standard glucoseglutamic acid sample 2. To ensure proper biological activity during the bod test, a wastewater sample. Test procedure the bod test takes 5 days to complete and is performed using a dissolved oxygen test kit. Running the biochemical oxygen demand bod test ebs. Other related analytical values are biochemical oxygen demand bod, total organic carbon toc, and total oxygen demand tod.
Also, it can be categorized in several ways such as. Biochemical oxygen demand bod testing determines the relative oxygen requirements of wastewaters, effluents, and polluted waters. In summary, the hach system for the apha bod test uses the same reagents, sample volumes, test conditions, and principles of operation as the traditional approach. The biochemical oxygen demand bod test tries to closely model an aerobic wastewater treatment system and the natural aquatic ecosystem. The difference between the two do levels represents the. Thus, this summarizes the difference between bod and cod. The bod value is calculated from the depletion and the amount of sample used. Add 2ml of manganese sulfate to the bod bottle carefully by inserting the pipette just below the surface of water. Jun 07, 2017 bod refers to the biochemical oxygen demand, which measures the amount of dissolved oxygen do required by aerobic organisms to break down organic material present in a given water sample at a given temperature and specified time. Biochemical oxygen demand bod test as described in 5210b standard methods, 20th edition, with a number of specific test requirements and differences in application. Among the considerations for a reliable test are the following. Overview of the two procedures for the 5day bod bod 5 test about the official procedure the procedure specified by the united states geological survey for the bod 5 test is done in the laboratory and is quite complex to perform and difficult to control for reliable results.
Understand the need and procedure for dilution and seeding in bod measurement. Accurate bod measurements with electrochemical and optical probes. Biochemical oxygen demand bod bod is an empiric laboratory assay which measures the amount of organic matter contained in a water sample. Geological surveystandard protocols and procedures. Biochemical oxygen demandbod test as described in 5210b standard methods, 20th edition, with a number of specific test requirements and differences in application. This publication is designed to provide a solid working knowledge of one of the major wastewater analytical test categories. Geological survey usgs develops the sampling procedures and collects the data necessary for the accurate assessment and wise management of our nations surfacewater and groundwater resources. Bod test requirements by tim loftus legend has it that the 5day bod biological oxygen demand test was developed in england. Standard dilution technique should be applied to samples with do depletion greater than 6 mgl. After the training the participants will be able to.
It measures oxygen taken up by the bacteria during the oxidation of organic matter. Since cod uses a strong oxidizing agent, it oxidizes pollutants completely into co 2 and h 2 o unlike in bod. Method summary a known volume of sample has its initial dissolved oxygen content recorded. The determination of chemical oxygen demand in waters. The oxygen content was measured using the azide method winkler modification.
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