Difference Between BOD and COD | Definition, Test Method and Procedure, Purpose
Ask the expert: What are the differences between Chemical Oxygen There is a strong correlation between COD and BOD, however COD. What is the difference between BOD and COD? BOD and COD measurements are taken to determine the pollution level of wastewater. BOD is. RELATIONSHIPS BETWEEN BOD, COD, TOD, TOC. BOD (Biochemical Oxygen Demand). This test is based on the amount of oxygen needed by.
Nitrogen either in the form of nitrate, nitrite, or ammonia can be health hazard. Presence of nitrate can cause methemoglobinemia if converted to nitrite [ 31516 ] and might contaminate groundwater [ 17 ]. Nitrite can also cause intestinal cancer [ 18 ]. Strict guidelines have been established by government agencies to prevent water contamination [ 38 ].
It is necessary to monitor the wastewater properly before discharge. Among the wastewater parameters, BOD is widely used as a primary indicator to gauge water pollution.
BOD provides information about the amount of biodegradable substance present in wastewater. As this is a bioassay test, the results depend not only on the kinetics exerted during the incubation period, but also on the microorganisms used; thus, the test exhibits poor repeatability.
Some of the industrial wastewaters have sufficient microbial population to perform the BOD5 test without providing an acclimated microbial seed. In comparison, there are other types of wastes, namely, untreated industrial wastes, disinfected wastes, and wastes that have been treated to a high temperature, that contain negligible bacterial population to perform the test.
Thus, these samples need to be seeded with a population of microorganisms to exert an oxygen demand. Seeding is a process in which the microorganisms that oxidize the organic matter present in a wastewater are added to the BOD bottle.
It has been confirmed that seeding in the BOD test, and in particular the source of seeding material, is a possible major source of error [ 20 ].
However, variations have been observed in BOD values when bacterial populations for seeding were procured either from different sources or from the same source at different time intervals. For all sources of seed, the possibility exists that some wastes will not be able to degrade by the microorganisms.
Difference Between BOD and COD - 572233.info
The BOD5 values of dairy wastewaters are often misleading since the normal seeding materials used for BOD5 estimation are nonspecific bacteria that cannot biodegrade some of the nitrogenous compounds present in the effluent. Some of these compounds are refractory to biodegradation because of high molecular weight coupled with lesser bioavailability.
The BOD analysis of dairy wastewater is problematic for many reasons; these include the heterogeneity of the samples at different times and nonspecific microorganism's present in general seeding material. The aforementioned problems can be overcome by formulating a uniform microbial seed comprising selected bacterial isolates thatare acclimatized to the dairy industrial wastewater.
Further, these bacterial isolates must be specific for the biodegradation of the organic compounds present in dairy effluent. Reproducible and reliable results may be obtained if a specifically designed formulated microbial consortium comprising selected bacterial strains is used as seed for the BOD5 analysis.
BOD and COD to characterise wastewater
The objective of this study is to isolate autochthonous bacteria from the industrial premises in order to develop a microbial consortium specifically formulated for use as seeding material for the BOD5 analysis of dairy industrial wastewater which will incorporate the utilization of nitrogen present in the dairy effluent.
Screening is done by conventional method and compared with already available seeding material. Statistical t-test is used to check the significance of the developed consortium.
Specific consortium was formulated so that the treatment can be effective and wastewater can be discharged after proper treatment. Normally water contains gases, inorganic ions, organic compounds, living organisms and some of the other trace chemical compounds.
The composition is varying depending on the different factors such as temperature, source and level of pollution. Particularly the microbial population and the dissolved oxygen concentration are changed with the alterations of the above-mentioned factors.
There is a significant relationship among organic matter, microbial population and finally with the dissolved oxygen content in water.
It can be nicely explained like this. Aerobic microbes need oxygen for their metabolism. They use dissolved oxygen and convert organic matter into energy.
BOD, COD, TOC and TOD – sum parameters in environmental analysis
They utilize the provided energy from organic food, for their further metabolic reactions and especially for their reproduction. The population density is increasing with respect to the gained energy, but it depends on the available food content. This metabolic requirement for the newly created population, again creates a demand for the dissolved oxygen, which is proportional to the available food. Therefore, the biological oxygen demand can be defined as the amount of dissolved oxygen required by aerobic organisms, to breakdown organic materials, in order to obtain energy for their metabolism.
This value should be tested under given temperature for a given period of time, and it will depend on the nutrient concentration and enzymatic reactions too.
BOD value in polluted water is normally higher than the fresh water.